fix(mise): migrate from unix only asdf backend to a universal one

- Add `rekey.proto` with `ContributePassphrase` / `ContributeRecoveryPassphrase` / `RekeyResult`
- Wire `rekey` as a 4th vault stream payload in `vault.proto` and gRPC dispatch
- Add `RekeyRootKey` message to `Vault` actor: generates new random seal key, re-encrypts root key, writes new `root_key_history` row
- Add `StartRekey`, `ContributeRekey`, `ContributeRecoveryRekey` messages to `VaultCoordinator`; `finalize_rekey` uses threshold-1 fast path identical to bootstrap
- `execute_replace_operator` now UPDATEs `operator_identity.public_key` in-place (avoids FK constraint violation), deletes stale `operator` share row, then triggers `StartRekey`
- `execute_update_shamir_parameters` triggers `StartRekey` instead of warning stub
- `ProposalKind::ReplaceOperator` carries `old_operator_id`; encode/decode updated accordingly
- `GlobalActors::spawn` extracts `vault_coordinator` before `Ok(Self { … })` so it can be cloned into `ProposalManager::new`
- Add `handle_rekey` in session handlers forwarding passphrase contributions to `VaultCoordinator`
- Fix test: rename `replace_operator_inserts_identity_row` → `replace_operator_updates_pubkey_and_starts_rekey`, assert count stays 1 and pubkey is updated

.claude/memory/feedback_widget_decomposition.md

@@ -0,0 +1,11 @@
+---
+name: Widget decomposition and provider subscriptions
+description: Prefer splitting screens into multiple focused files/widgets; each widget subscribes to its own relevant providers
+type: feedback
+---
+
+Split screens into multiple smaller widgets across multiple files. Each widget should subscribe only to the providers it needs (`ref.watch` at lowest possible level), rather than having one large screen widget that watches everything and passes data down as parameters.
+
+**Why:** Reduces unnecessary rebuilds; improves readability; each file has one clear responsibility.
+
+**How to apply:** When building a new screen, identify which sub-widgets need their own provider subscriptions and extract them into separate files (e.g., `widgets/grant_card.dart` watches enrichment providers itself, rather than the screen doing it and passing resolved strings down).

.gitattributes

@@ -0,0 +1 @@
+* text=auto eol=lf

.gitignore

@@ -1,3 +1,6 @@
 target/
 scripts/__pycache__/
-.DS_Store
+.DS_Store
+.cargo/config.toml
+.vscode/
+docs/superpowers

.vscode/settings.json

@@ -1,3 +0,0 @@
-{
-    "git.enabled": false
-}

.woodpecker/server-lint.yaml

@@ -22,4 +22,4 @@ steps:
       - apt-get update && apt-get install -y pkg-config
       - mise install rust 
       - mise install protoc
-      - mise exec rust -- cargo clippy --all-targets --all-features -- -D warnings
+      - mise exec rust -- cargo clippy --all -- -D warnings

.woodpecker/server-test.yaml

@@ -24,4 +24,4 @@ steps:
       - mise install rust 
       - mise install protoc
       - mise install cargo:cargo-nextest
-      - mise exec cargo:cargo-nextest -- cargo nextest run --no-fail-fast
+      - mise exec cargo:cargo-nextest -- cargo nextest run --no-fail-fast --all-features

.woodpecker/useragent-analyze.yaml

@@ -0,0 +1,18 @@
+when:
+  - event: pull_request
+    path:
+      include: ['.woodpecker/useragent-*.yaml', 'useragent/**']
+  - event: push
+    branch: main
+    path:
+      include: ['.woodpecker/useragent-*.yaml', 'useragent/**']
+
+steps:
+  - name: analyze
+    image: jdxcode/mise:latest
+    commands:
+      - mise install flutter 
+      - mise install protoc
+      # Reruns codegen to catch protocol drift
+      - mise codegen 
+      - cd useragent/ && flutter analyze

AGENTS.md

@@ -0,0 +1,149 @@
+# AGENTS.md
+
+This file provides guidance to Codex (Codex.ai/code) when working with code in this repository.
+
+## Project Overview
+
+Arbiter is a **permissioned signing service** for cryptocurrency wallets. It consists of:
+- **`server/`** — Rust gRPC daemon that holds encrypted keys and enforces policies
+- **`operator/`** — Flutter desktop app (macOS/Windows) with a Rust backend via Rinf
+- **`protobufs/`** — Protocol Buffer definitions shared between server and client
+
+The vault never exposes key material; it only produces signatures when requests satisfy configured policies.
+
+## Toolchain Setup
+
+Tools are managed via [mise](https://mise.jdx.dev/). Install all required tools:
+```sh
+mise install
+```
+
+Key versions: Rust 1.93.0 (with clippy), Flutter 3.38.9-stable, protoc 29.6, diesel_cli 2.3.6 (sqlite).
+
+## Server (Rust workspace at `server/`)
+
+### Crates
+
+| Crate | Purpose |
+|---|---|
+| `arbiter-proto` | Generated gRPC stubs + protobuf types; compiled from `protobufs/*.proto` via `tonic-prost-build` |
+| `arbiter-server` | Main daemon — actors, DB, EVM policy engine, gRPC service implementation |
+| `arbiter-operator` | Rust client library for the operator side of the gRPC protocol |
+| `arbiter-client` | Rust client library for SDK clients |
+
+### Common Commands
+
+```sh
+cd server
+
+# Build
+cargo build
+
+# Run the server daemon
+cargo run -p arbiter-server
+
+# Run all tests (preferred over cargo test)
+cargo nextest run
+
+# Run a single test
+cargo nextest run <test_name>
+
+# Lint
+cargo clippy
+
+# Security audit
+cargo audit
+
+# Check unused dependencies
+cargo shear
+
+# Run snapshot tests and update snapshots
+cargo insta review
+```
+
+### Architecture
+
+The server is actor-based using the **kameo** crate. All long-lived state lives in `GlobalActors`:
+
+- **`Bootstrapper`** — Manages the one-time bootstrap token written to `~/.arbiter/bootstrap_token` on first run.
+- **`Vault`** — Holds the encrypted root key and manages the Sealed/Unsealed vault state machine. On unseal, decrypts the root key into a `memsafe` hardened memory cell.
+- **`FlowCoordinator`** — Coordinates cross-connection flow between operators and SDK clients.
+- **`EvmActor`** — Handles EVM transaction policy enforcement and signing.
+
+Per-connection actors live under `actors/operator/` and `actors/client/`, each with `auth` (challenge-response authentication) and `session` (post-auth operations) sub-modules.
+
+**Database:** SQLite via `diesel-async` + `bb8` connection pool. Schema managed by embedded Diesel migrations in `crates/arbiter-server/migrations/`. DB file lives at `~/.arbiter/arbiter.sqlite`. Tests use a temp-file DB via `db::create_test_pool()`.
+
+**Cryptography:**
+- Authentication: ed25519 (challenge-response, nonce-tracked per peer)
+- Encryption at rest: XChaCha20-Poly1305 (versioned via `scheme` field for transparent migration on unseal)
+- Password KDF: Argon2
+- Unseal transport: X25519 ephemeral key exchange
+- TLS: self-signed certificate (aws-lc-rs backend), fingerprint distributed via `ArbiterUrl`
+
+**Protocol:** gRPC with Protocol Buffers. The `ArbiterUrl` type encodes host, port, CA cert, and bootstrap token into a single shareable string (printed to console on first run).
+
+### Proto Regeneration
+
+When `.proto` files in `protobufs/` change, rebuild to regenerate:
+```sh
+cd server && cargo build -p arbiter-proto
+```
+
+### Database Migrations
+
+```sh
+# Create a new migration
+diesel migration generate <name> --migration-dir crates/arbiter-server/migrations
+
+# Run migrations manually (server also runs them on startup)
+diesel migration run --migration-dir crates/arbiter-server/migrations
+```
+
+### Code Conventions
+
+**`#[must_use]` Attribute:**
+Apply the `#[must_use]` attribute to return types of functions where the return value is critical and should not be accidentally ignored. This is commonly used for:
+
+- Methods that return `bool` indicating success/failure or validation state
+- Any function where ignoring the return value indicates a logic error
+
+Do not apply `#[must_use]` redundantly to items (types or functions) that are already annotated with `#[must_use]`.
+
+Example:
+
+```rust
+#[must_use]
+pub fn verify(&self, nonce: i32, context: &[u8], signature: &Signature) -> bool {
+    // verification logic
+}
+```
+
+This forces callers to either use the return value or explicitly ignore it with `let _ = ...;`, preventing silent failures.
+
+## Operator (Flutter + Rinf at `operator/`)
+
+The Flutter app uses [Rinf](https://rinf.cunarist.org) to call Rust code. The Rust logic lives in `operator/native/hub/` as a separate crate that uses `arbiter-operator` for the gRPC client.
+
+Communication between Dart and Rust uses typed **signals** defined in `operator/native/hub/src/signals/`. After modifying signal structs, regenerate Dart bindings:
+
+```sh
+cd operator && rinf gen
+```
+
+### Common Commands
+
+```sh
+cd operator
+
+# Run the app (macOS or Windows)
+flutter run
+
+# Regenerate Rust↔Dart signal bindings
+rinf gen
+
+# Analyze Dart code
+flutter analyze
+```
+
+The Rinf Rust entry point is `operator/native/hub/src/lib.rs`. It spawns actors defined in `operator/native/hub/src/actors/` which handle Dart↔server communication via signals.

ARCHITECTURE.md

@@ -1,155 +0,0 @@
-# Arbiter
-
-Arbiter is a permissioned signing service for cryptocurrency wallets. It runs as a background service on the user's machine with an optional client application for vault management.
-
-**Core principle:** The vault NEVER exposes key material. It only produces signatures when a request satisfies the configured policies.
----
-
-## 1. Peer Types
-
-Arbiter distinguishes two kinds of peers:
-
-- **User Agent** — A client application used by the owner to manage the vault (create wallets, approve SDK clients, configure policies).
-- **SDK Client** — A consumer of signing capabilities, typically an automation tool. In the future, this could include a browser-based wallet.
-
----
-
-## 2. Authentication
-
-### 2.1 Challenge-Response
-
-All peers authenticate via public-key cryptography using a challenge-response protocol:
-
-1. The peer sends its public key and requests a challenge.
-2. The server looks up the key in its database. If found, it increments the nonce and returns a challenge (replay-attack protection).
-3. The peer signs the challenge with its private key and sends the signature back.
-4. The server verifies the signature:
-   - **Pass:** The connection is considered authenticated.
-   - **Fail:** The server closes the connection.
-
-### 2.2 User Agent Bootstrap
-
-On first run — when no User Agents are registered — the server generates a one-time bootstrap token. It is made available in two ways:
-
-- **Local setup:** Written to `~/.arbiter/bootstrap_token` for automatic discovery by a co-located User Agent.
-- **Remote setup:** Printed to the server's console output.
-
-The first User Agent must present this token alongside the standard challenge-response to complete registration.
-
-### 2.3 SDK Client Registration
-
-There is no bootstrap mechanism for SDK clients. They must be explicitly approved by an already-registered User Agent.
-
----
-
-## 3. Server Identity
-
-The server proves its identity using TLS with a self-signed certificate. The TLS private key is generated on first run and is long-term; no rotation mechanism exists yet due to the complexity of multi-peer coordination.
-
-Peers verify the server by its **public key fingerprint**:
-
-- **User Agent (local):** Receives the fingerprint automatically through the bootstrap token.
-- **User Agent (remote) / SDK Client:** Must receive the fingerprint out-of-band.
-
-> A streamlined setup mechanism using a single connection string is planned but not yet implemented.
-
----
-
-## 4. Key Management
-
-### 4.1 Key Hierarchy
-
-There are three layers of keys:
-
-| Key | Encrypts | Encrypted by |
-|---|---|---|
-| **User key** (password) | Root key | — (derived from user input) |
-| **Root key** | Wallet keys | User key |
-| **Wallet keys** | — (used for signing) | Root key |
-
-This layered design enables:
-
-- **Password rotation** without re-encrypting every wallet key (only the root key is re-encrypted).
-- **Root key rotation** without requiring the user to change their password.
-
-### 4.2 Encryption at Rest
-
-The database stores everything in encrypted form using symmetric AEAD. The encryption scheme is versioned to support transparent migration — when the vault unseals, Arbiter automatically re-encrypts any entries that are behind the current scheme version. See [IMPLEMENTATION.md](IMPLEMENTATION.md) for the specific scheme and versioning mechanism.
-
----
-
-## 5. Vault Lifecycle
-
-### 5.1 Sealed State
-
-On boot, the root key is encrypted and the server cannot perform any signing operations. This state is called **Sealed**.
-
-### 5.2 Unseal Flow
-
-To transition to the **Unsealed** state, a User Agent must provide the password:
-
-1. The User Agent initiates an unseal request.
-2. The server generates a one-time key pair and returns the public key.
-3. The User Agent encrypts the user's password with this one-time public key and sends the ciphertext to the server.
-4. The server decrypts and verifies the password:
-   - **Success:** The root key is decrypted and placed into a hardened memory cell. The server transitions to `Unsealed`. Any entries pending encryption scheme migration are re-encrypted.
-   - **Failure:** The server returns an error indicating the password is incorrect.
-
-### 5.3 Memory Protection
-
-Once unsealed, the root key must be protected in memory against:
-
-- Memory dumps
-- Page swaps to disk
-- Hibernation files
-
-See [IMPLEMENTATION.md](IMPLEMENTATION.md) for the current and planned memory protection approaches.
-
----
-
-## 6. Permission Engine
-
-### 6.1 Fundamental Rules
-
-- SDK clients have **no access by default**.
-- Access is granted **explicitly** by a User Agent.
-- Grants are scoped to **specific wallets** and governed by **policies**.
-
-Each blockchain requires its own policy system due to differences in static transaction analysis. Currently, only EVM is supported; Solana support is planned.
-
-Arbiter is also responsible for ensuring that **transaction nonces are never reused**.
-
-### 6.2 EVM Policies
-
-Every EVM grant is scoped to a specific **wallet** and **chain ID**.
-
-#### 6.2.1 Transaction Sub-Grants
-
-Arbiter maintains an ever-expanding database of known contracts and their ABIs. Based on contract knowledge, transaction requests fall into three categories:
-
-**1. Known contract (ABI available)**
-
-The transaction can be decoded and presented with semantic meaning. For example: *"Client X wants to transfer Y USDT to address Z."*
-
-Available restrictions:
-- Volume limits (e.g., "no more than 10,000 tokens ever")
-- Rate limits (e.g., "no more than 100 tokens per hour")
-
-**2. Unknown contract (no ABI)**
-
-The transaction cannot be decoded, so its effects are opaque — it could do anything, including draining all tokens. The user is warned, and if approved, access is granted to all interactions with the contract (matched by the `to` field).
-
-Available restrictions:
-- Transaction count limits (e.g., "no more than 100 transactions ever")
-- Rate limits (e.g., "no more than 5 transactions per hour")
-
-**3. Plain ether transfer (no calldata)**
-
-These transactions have no `calldata` and therefore cannot interact with contracts. They can be subject to the same volume and rate restrictions as above.
-
-#### 6.2.2 Global Limits
-
-In addition to sub-grant-specific restrictions, the following limits can be applied across all grant types:
-
-- **Gas limit** — Maximum gas per transaction.
-- **Time-window restrictions** — e.g., signing allowed only 08:00–20:00 on Mondays and Thursdays.

CLAUDE.md

@@ -0,0 +1 @@
+Refer to @AGENTS.md for instructions.

README.md

@@ -4,7 +4,7 @@
 ## Security warning
 Arbiter can't meaningfully protect against host compromise. Potential attack flow:
 - Attacker steals TLS keys from database
-- Pretends to be server; just accepts user agent challenge solutions
+- Pretends to be server; just accepts operator challenge solutions
 - Pretend to be in sealed state and performing DH with client
 - Steals user password and derives seal key
 

app/.dart_tool/extension_discovery/README.md

@@ -1,31 +0,0 @@
-Extension Discovery Cache
-=========================
-
-This folder is used by `package:extension_discovery` to cache lists of
-packages that contains extensions for other packages.
-
-DO NOT USE THIS FOLDER
-----------------------
-
- * Do not read (or rely) the contents of this folder.
- * Do write to this folder.
-
-If you're interested in the lists of extensions stored in this folder use the
-API offered by package `extension_discovery` to get this information.
-
-If this package doesn't work for your use-case, then don't try to read the
-contents of this folder. It may change, and will not remain stable.
-
-Use package `extension_discovery`
----------------------------------
-
-If you want to access information from this folder.
-
-Feel free to delete this folder
--------------------------------
-
-Files in this folder act as a cache, and the cache is discarded if the files
-are older than the modification time of `.dart_tool/package_config.json`.
-
-Hence, it should never be necessary to clear this cache manually, if you find a
-need to do please file a bug.

app/.dart_tool/extension_discovery/vs_code.json

@@ -1 +0,0 @@
-{"version":2,"entries":[{"package":"app","rootUri":"../","packageUri":"lib/"}]}

app/.dart_tool/package_config.json

@@ -1,178 +0,0 @@
-{
-  "configVersion": 2,
-  "packages": [
-    {
-      "name": "async",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/async-2.13.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "boolean_selector",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/boolean_selector-2.1.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "characters",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/characters-1.4.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "clock",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/clock-1.1.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "collection",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/collection-1.19.1",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "cupertino_icons",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/cupertino_icons-1.0.8",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "fake_async",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/fake_async-1.3.3",
-      "packageUri": "lib/",
-      "languageVersion": "3.3"
-    },
-    {
-      "name": "flutter",
-      "rootUri": "file:///Users/kaska/.local/share/mise/installs/flutter/3.38.9-stable/packages/flutter",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "flutter_lints",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/flutter_lints-6.0.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "flutter_test",
-      "rootUri": "file:///Users/kaska/.local/share/mise/installs/flutter/3.38.9-stable/packages/flutter_test",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "leak_tracker",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/leak_tracker-11.0.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.2"
-    },
-    {
-      "name": "leak_tracker_flutter_testing",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/leak_tracker_flutter_testing-3.0.10",
-      "packageUri": "lib/",
-      "languageVersion": "3.2"
-    },
-    {
-      "name": "leak_tracker_testing",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/leak_tracker_testing-3.0.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.2"
-    },
-    {
-      "name": "lints",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/lints-6.1.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "matcher",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/matcher-0.12.17",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "material_color_utilities",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/material_color_utilities-0.11.1",
-      "packageUri": "lib/",
-      "languageVersion": "2.17"
-    },
-    {
-      "name": "meta",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/meta-1.17.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.5"
-    },
-    {
-      "name": "path",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/path-1.9.1",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "sky_engine",
-      "rootUri": "file:///Users/kaska/.local/share/mise/installs/flutter/3.38.9-stable/bin/cache/pkg/sky_engine",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "source_span",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/source_span-1.10.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "stack_trace",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/stack_trace-1.12.1",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "stream_channel",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/stream_channel-2.1.4",
-      "packageUri": "lib/",
-      "languageVersion": "3.3"
-    },
-    {
-      "name": "string_scanner",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/string_scanner-1.4.1",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "term_glyph",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/term_glyph-1.2.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "test_api",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/test_api-0.7.7",
-      "packageUri": "lib/",
-      "languageVersion": "3.5"
-    },
-    {
-      "name": "vector_math",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/vector_math-2.2.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "vm_service",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/vm_service-15.0.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.5"
-    },
-    {
-      "name": "app",
-      "rootUri": "../",
-      "packageUri": "lib/",
-      "languageVersion": "3.10"
-    }
-  ],
-  "generator": "pub",
-  "generatorVersion": "3.10.8",
-  "flutterRoot": "file:///Users/kaska/.local/share/mise/installs/flutter/3.38.9-stable",
-  "flutterVersion": "3.38.9",
-  "pubCache": "file:///Users/kaska/.pub-cache"
-}

app/.dart_tool/package_graph.json

@@ -1,230 +0,0 @@
-{
-  "roots": [
-    "app"
-  ],
-  "packages": [
-    {
-      "name": "app",
-      "version": "1.0.0+1",
-      "dependencies": [
-        "cupertino_icons",
-        "flutter"
-      ],
-      "devDependencies": [
-        "flutter_lints",
-        "flutter_test"
-      ]
-    },
-    {
-      "name": "flutter_lints",
-      "version": "6.0.0",
-      "dependencies": [
-        "lints"
-      ]
-    },
-    {
-      "name": "flutter_test",
-      "version": "0.0.0",
-      "dependencies": [
-        "clock",
-        "collection",
-        "fake_async",
-        "flutter",
-        "leak_tracker_flutter_testing",
-        "matcher",
-        "meta",
-        "path",
-        "stack_trace",
-        "stream_channel",
-        "test_api",
-        "vector_math"
-      ]
-    },
-    {
-      "name": "cupertino_icons",
-      "version": "1.0.8",
-      "dependencies": []
-    },
-    {
-      "name": "flutter",
-      "version": "0.0.0",
-      "dependencies": [
-        "characters",
-        "collection",
-        "material_color_utilities",
-        "meta",
-        "sky_engine",
-        "vector_math"
-      ]
-    },
-    {
-      "name": "lints",
-      "version": "6.1.0",
-      "dependencies": []
-    },
-    {
-      "name": "stream_channel",
-      "version": "2.1.4",
-      "dependencies": [
-        "async"
-      ]
-    },
-    {
-      "name": "meta",
-      "version": "1.17.0",
-      "dependencies": []
-    },
-    {
-      "name": "collection",
-      "version": "1.19.1",
-      "dependencies": []
-    },
-    {
-      "name": "leak_tracker_flutter_testing",
-      "version": "3.0.10",
-      "dependencies": [
-        "flutter",
-        "leak_tracker",
-        "leak_tracker_testing",
-        "matcher",
-        "meta"
-      ]
-    },
-    {
-      "name": "vector_math",
-      "version": "2.2.0",
-      "dependencies": []
-    },
-    {
-      "name": "stack_trace",
-      "version": "1.12.1",
-      "dependencies": [
-        "path"
-      ]
-    },
-    {
-      "name": "clock",
-      "version": "1.1.2",
-      "dependencies": []
-    },
-    {
-      "name": "fake_async",
-      "version": "1.3.3",
-      "dependencies": [
-        "clock",
-        "collection"
-      ]
-    },
-    {
-      "name": "path",
-      "version": "1.9.1",
-      "dependencies": []
-    },
-    {
-      "name": "matcher",
-      "version": "0.12.17",
-      "dependencies": [
-        "async",
-        "meta",
-        "stack_trace",
-        "term_glyph",
-        "test_api"
-      ]
-    },
-    {
-      "name": "test_api",
-      "version": "0.7.7",
-      "dependencies": [
-        "async",
-        "boolean_selector",
-        "collection",
-        "meta",
-        "source_span",
-        "stack_trace",
-        "stream_channel",
-        "string_scanner",
-        "term_glyph"
-      ]
-    },
-    {
-      "name": "sky_engine",
-      "version": "0.0.0",
-      "dependencies": []
-    },
-    {
-      "name": "material_color_utilities",
-      "version": "0.11.1",
-      "dependencies": [
-        "collection"
-      ]
-    },
-    {
-      "name": "characters",
-      "version": "1.4.0",
-      "dependencies": []
-    },
-    {
-      "name": "async",
-      "version": "2.13.0",
-      "dependencies": [
-        "collection",
-        "meta"
-      ]
-    },
-    {
-      "name": "leak_tracker_testing",
-      "version": "3.0.2",
-      "dependencies": [
-        "leak_tracker",
-        "matcher",
-        "meta"
-      ]
-    },
-    {
-      "name": "leak_tracker",
-      "version": "11.0.2",
-      "dependencies": [
-        "clock",
-        "collection",
-        "meta",
-        "path",
-        "vm_service"
-      ]
-    },
-    {
-      "name": "term_glyph",
-      "version": "1.2.2",
-      "dependencies": []
-    },
-    {
-      "name": "string_scanner",
-      "version": "1.4.1",
-      "dependencies": [
-        "source_span"
-      ]
-    },
-    {
-      "name": "source_span",
-      "version": "1.10.2",
-      "dependencies": [
-        "collection",
-        "path",
-        "term_glyph"
-      ]
-    },
-    {
-      "name": "boolean_selector",
-      "version": "2.1.2",
-      "dependencies": [
-        "source_span",
-        "string_scanner"
-      ]
-    },
-    {
-      "name": "vm_service",
-      "version": "15.0.2",
-      "dependencies": []
-    }
-  ],
-  "configVersion": 1
-}

app/.dart_tool/version

@@ -1 +0,0 @@
-3.38.9

docs/ARCHITECTURE.md

@@ -0,0 +1,334 @@
+# Arbiter
+
+Arbiter is a permissioned signing service for cryptocurrency wallets. It runs as a background service on the user's machine with an optional client application for vault management.
+
+**Core principle:** The vault NEVER exposes key material. It only produces signatures when a request satisfies the configured policies.
+---
+
+## 1. Peer Types
+
+Arbiter distinguishes two kinds of peers:
+
+- **Operator** — A client application used by the owner to manage the vault (create wallets, approve SDK clients, configure policies).
+- **SDK Client** — A consumer of signing capabilities, typically an automation tool. In the future, this could include a browser-based wallet.
+- **Recovery Operator** — A dormant recovery participant with narrowly scoped authority used only for custody recovery and operator replacement.
+
+---
+
+## 2. Authentication
+
+### 2.1 Challenge-Response
+
+All peers authenticate via public-key cryptography using a challenge-response protocol:
+
+1. The peer sends its public key and requests a challenge.
+2. The server looks up the key in its database. If found, it generates a fresh challenge from random bytes plus the current timestamp.
+3. The peer signs the canonical challenge payload with its private key and sends the signature back.
+4. The server verifies the signature:
+   - **Pass:** The connection is considered authenticated.
+   - **Fail:** The server closes the connection.
+
+Authentication challenges are per-connection, ephemeral values. They are not persisted in the peer tables, and peer records store no challenge state.
+
+### 2.2 Operator Bootstrap
+
+On first run — when no Operators are registered — the server generates a one-time bootstrap token. It is made available in two ways:
+
+- **Local setup:** Written to `~/.arbiter/bootstrap_token` for automatic discovery by a co-located Operator.
+- **Remote setup:** Printed to the server's console output.
+
+The first Operator must present this token alongside the standard challenge-response to complete registration.
+
+### 2.3 SDK Client Registration
+
+There is no bootstrap mechanism for SDK clients. They must be explicitly approved by an already-registered Operator.
+
+---
+
+## 3. Multi-Operator Governance
+
+When more than one Operator is registered, the vault is treated as having multiple operators. In that mode, sensitive actions are governed by voting rather than by a single operator decision.
+
+### 3.1 Voting Rules
+
+Voting is based on the total number of registered operators:
+
+- **1 operator:** no vote is needed; the single operator decides directly.
+- **2 operators:** full consensus is required; both operators must approve.
+- **3 or more operators:** quorum is `floor(N / 2) + 1`.
+
+For a decision to count, the operator's approval or rejection must be signed by that operator's associated key. Unsigned votes, or votes that fail signature verification, are ignored.
+
+Examples:
+
+- **3 operators:** 2 approvals required
+- **4 operators:** 3 approvals required
+
+### 3.2 Actions Requiring a Vote
+
+In multi-operator mode, a successful vote is required for:
+
+- approving new SDK clients
+- granting an SDK client visibility to a wallet
+- approving a one-off transaction
+- approving creation of a persistent grant
+- approving operator replacement
+- approving server updates
+- updating Shamir secret-sharing parameters
+
+### 3.3 Special Rule for Key Rotation
+
+Key rotation always requires full quorum, regardless of the normal voting threshold.
+
+This is stricter than ordinary governance actions because rotating the root key requires every operator to participate in coordinated share refresh/update steps. The root key itself is not redistributed directly, but each operator's share material must be changed consistently.
+
+### 3.4 Root Key Custody
+
+When the vault has multiple operators, the vault root key is protected using Shamir secret sharing.
+
+The vault root key is encrypted in a way that requires reconstruction from user-held shares rather than from a single shared password.
+
+For ordinary operators, the Shamir threshold matches the ordinary governance quorum. For example:
+
+- **2 operators:** `2-of-2`
+- **3 operators:** `2-of-3`
+- **4 operators:** `3-of-4`
+
+In practice, the Shamir share set also includes Recovery Operator shares. This means the effective Shamir parameters are computed over the combined share pool while keeping the same threshold. For example:
+
+- **3 ordinary operators + 2 recovery shares:** `2-of-5`
+
+This ensures that the normal custody threshold follows the ordinary operator quorum, while still allowing dormant recovery shares to exist for break-glass recovery flows.
+
+### 3.5 Recovery Operators
+
+Recovery Operators are a separate peer type from ordinary vault operators.
+
+Their role is intentionally narrow. They can only:
+
+- participate in unsealing the vault
+- vote for operator replacement
+
+Recovery Operators do not participate in routine governance such as approving SDK clients, granting wallet visibility, approving transactions, creating grants, approving server updates, or changing Shamir parameters.
+
+### 3.6 Sleeping and Waking Recovery Operators
+
+By default, Recovery Operators are **sleeping** and do not participate in any active flow.
+
+Any ordinary operator may request that Recovery Operators **wake up**.
+
+Any ordinary operator may also cancel a pending wake-up request.
+
+This creates a dispute window before recovery powers become active. The default wake-up delay is **14 days**.
+
+Recovery Operators are therefore part of the break-glass recovery path rather than the normal operating quorum.
+
+The high-level recovery flow is:
+
+```mermaid
+sequenceDiagram
+    autonumber
+    actor Op as Ordinary Operator
+    participant Server
+    actor Other as Other Operator
+    actor Rec as Recovery Operator
+
+    Op->>Server: Request recovery wake-up
+    Server-->>Op: Wake-up pending
+    Note over Server: Default dispute window: 14 days
+
+    alt Wake-up cancelled during dispute window
+        Other->>Server: Cancel wake-up
+        Server-->>Op: Recovery cancelled
+        Server-->>Rec: Stay sleeping
+    else No cancellation for 14 days
+        Server-->>Rec: Wake up
+        Rec->>Server: Join recovery flow
+        critical Recovery authority
+            Rec->>Server: Participate in unseal
+            Rec->>Server: Vote on operator replacement
+        end
+        Server-->>Op: Recovery mode active
+    end
+```
+
+### 3.7 Committee Formation
+
+There are two ways to form a multi-operator committee:
+
+- convert an existing single-operator vault by adding new operators
+- bootstrap an unbootstrapped vault directly into multi-operator mode
+
+In both cases, committee formation is a coordinated process. Arbiter does not allow multi-operator custody to emerge implicitly from unrelated registrations.
+
+### 3.8 Bootstrapping an Unbootstrapped Vault into Multi-Operator Mode
+
+When an unbootstrapped vault is initialized as a multi-operator vault, the setup proceeds as follows:
+
+1. An operator connects to the unbootstrapped vault using an Operator and the bootstrap token.
+2. During bootstrap setup, that operator declares:
+   - the total number of ordinary operators
+   - the total number of Recovery Operators
+3. The vault enters **multi-bootstrap mode**.
+4. While in multi-bootstrap mode:
+   - every ordinary operator must connect with an Operator using the bootstrap token
+   - every Recovery Operator must also connect using the bootstrap token
+   - each participant is registered individually
+   - each participant's share is created and protected with that participant's credentials
+5. The vault is considered fully bootstrapped only after all declared operator and recovery-share registrations have completed successfully.
+
+This means the operator and recovery set is fixed at bootstrap completion time, based on the counts declared when multi-bootstrap mode was entered.
+
+### 3.9 Special Bootstrap Constraint for Two-Operator Vaults
+
+If a vault is declared with exactly **2 ordinary operators**, Arbiter requires at least **1 Recovery Operator** to be configured during bootstrap.
+
+This prevents the worst-case custody failure in which a `2-of-2` operator set becomes permanently unrecoverable after loss of a single operator.
+
+---
+
+## 4. Server Identity
+
+The server proves its identity using TLS with a self-signed certificate. The TLS private key is generated on first run and is long-term; no rotation mechanism exists yet due to the complexity of multi-peer coordination.
+
+Peers verify the server by its **public key fingerprint**:
+
+- **Operator (local):** Receives the fingerprint automatically through the bootstrap token.
+- **Operator (remote) / SDK Client:** Must receive the fingerprint out-of-band.
+
+> A streamlined setup mechanism using a single connection string is planned but not yet implemented.
+
+---
+
+## 5. Key Management
+
+### 5.1 Key Hierarchy
+
+There are three layers of keys:
+
+| Key | Encrypts | Encrypted by |
+|---|---|---|
+| **User key** (password) | Root key | — (derived from user input) |
+| **Root key** | Wallet keys | User key |
+| **Wallet keys** | — (used for signing) | Root key |
+
+This layered design enables:
+
+- **Password rotation** without re-encrypting every wallet key (only the root key is re-encrypted).
+- **Root key rotation** without requiring the user to change their password.
+
+### 5.2 Encryption at Rest
+
+The database stores everything in encrypted form using symmetric AEAD. The encryption scheme is versioned to support transparent migration — when the vault unseals, Arbiter automatically re-encrypts any entries that are behind the current scheme version. See [IMPLEMENTATION.md](IMPLEMENTATION.md) for the specific scheme and versioning mechanism.
+
+---
+
+## 6. Vault Lifecycle
+
+### 6.1 Sealed State
+
+On boot, the root key is encrypted and the server cannot perform any signing operations. This state is called **Sealed**.
+
+### 6.2 Unseal Flow
+
+To transition to the **Unsealed** state, an Operator must provide the password:
+
+1. The Operator initiates an unseal request.
+2. The server generates a one-time key pair and returns the public key.
+3. The Operator encrypts the user's password with this one-time public key and sends the ciphertext to the server.
+4. The server decrypts and verifies the password:
+   - **Success:** The root key is decrypted and placed into a hardened memory cell. The server transitions to `Unsealed`. Any entries pending encryption scheme migration are re-encrypted.
+   - **Failure:** The server returns an error indicating the password is incorrect.
+
+### 6.3 Memory Protection
+
+Once unsealed, the root key must be protected in memory against:
+
+- Memory dumps
+- Page swaps to disk
+- Hibernation files
+
+See [IMPLEMENTATION.md](IMPLEMENTATION.md) for the current and planned memory protection approaches.
+
+---
+
+## 7. Permission Engine
+
+### 7.1 Fundamental Rules
+
+- SDK clients have **no access by default**.
+- Access is granted **explicitly** by an Operator.
+- Grants are scoped to **specific wallets** and governed by **policies**.
+
+Each blockchain requires its own policy system due to differences in static transaction analysis. Currently, only EVM is supported; Solana support is planned.
+
+Arbiter is also responsible for ensuring that **transaction nonces are never reused**.
+
+### 7.2 EVM Policies
+
+Every EVM grant is scoped to a specific **wallet** and **chain ID**.
+
+#### 7.2.0 Transaction Signing Sequence
+
+The high-level interaction order is:
+
+```mermaid
+sequenceDiagram
+    autonumber
+    actor SDK as SDK Client
+    participant Server
+    participant operator as Operator
+
+    SDK->>Server: SignTransactionRequest
+    Server->>Server: Resolve wallet and wallet visibility
+    alt Visibility approval required
+        Server->>operator: Ask for wallet visibility approval
+        operator-->>Server: Vote result
+    end
+    Server->>Server: Evaluate transaction
+    Server->>Server: Load grant and limits context
+    alt Grant approval required
+        Server->>operator: Ask for execution / grant approval
+        operator-->>Server: Vote result
+        opt Create persistent grant
+            Server->>Server: Create and store grant
+        end
+        Server->>Server: Retry evaluation
+    end
+    critical Final authorization path
+        Server->>Server: Check limits and record execution
+        Server-->>Server: Signature or evaluation error
+    end
+    Server-->>SDK: Signature or error
+```
+
+#### 7.2.1 Transaction Sub-Grants
+
+Arbiter maintains an ever-expanding database of known contracts and their ABIs. Based on contract knowledge, transaction requests fall into three categories:
+
+**1. Known contract (ABI available)**
+
+The transaction can be decoded and presented with semantic meaning. For example: *"Client X wants to transfer Y USDT to address Z."*
+
+Available restrictions:
+- Volume limits (e.g., "no more than 10,000 tokens ever")
+- Rate limits (e.g., "no more than 100 tokens per hour")
+
+**2. Unknown contract (no ABI)**
+
+The transaction cannot be decoded, so its effects are opaque — it could do anything, including draining all tokens. The user is warned, and if approved, access is granted to all interactions with the contract (matched by the `to` field).
+
+Available restrictions:
+- Transaction count limits (e.g., "no more than 100 transactions ever")
+- Rate limits (e.g., "no more than 5 transactions per hour")
+
+**3. Plain ether transfer (no calldata)**
+
+These transactions have no `calldata` and therefore cannot interact with contracts. They can be subject to the same volume and rate restrictions as above.
+
+#### 7.2.2 Global Limits
+
+In addition to sub-grant-specific restrictions, the following limits can be applied across all grant types:
+
+- **Gas limit** — Maximum gas per transaction.
+- **Time-window restrictions** — e.g., signing allowed only 08:00–20:00 on Mondays and Thursdays.

docs/IMPLEMENTATION.md

@@ -4,10 +4,68 @@ This document covers concrete technology choices and dependencies. For the archi
 
 ---
 
+## Client Connection Flow
+
+### Authentication Result Semantics
+
+Authentication no longer uses an implicit success-only response shape. Both `client` and `operator` return explicit auth status enums over the wire.
+
+- **Client:** `AuthResult` may return `SUCCESS`, `INVALID_KEY`, `INVALID_SIGNATURE`, `APPROVAL_DENIED`, `NO_OPERATORS_ONLINE`, or `INTERNAL`
+- **Operator:** `AuthResult` may return `SUCCESS`, `INVALID_KEY`, `INVALID_SIGNATURE`, `BOOTSTRAP_REQUIRED`, `TOKEN_INVALID`, or `INTERNAL`
+
+This makes transport-level failures and actor/domain-level auth failures distinct:
+
+- **Transport/protocol failures** are surfaced as stream/status errors
+- **Authentication failures** are surfaced as successful protocol responses carrying an explicit auth status
+
+Clients are expected to handle these status codes directly and present the concrete failure reason to the user.
+
+### New Client Approval
+
+When a client whose public key is not yet in the database connects, all connected operators are asked to approve the connection. The first operator to respond determines the outcome; remaining requests are cancelled via a watch channel.
+
+```mermaid
+flowchart TD
+    A([Client connects]) --> B[Receive AuthChallengeRequest]
+    B --> C{pubkey in DB?}
+
+    C -- yes --> G[Generate AuthChallenge]
+
+    C -- no --> E[Ask all Operators:\nClientConnectionRequest]
+    E --> F{First response}
+    F -- denied --> Z([Reject connection])
+    F -- approved --> F2[Cancel remaining\nOperator requests]
+    F2 --> F3[INSERT client]
+    F3 --> G
+
+    G --> H[Send AuthChallenge\ntimestamp + random bytes]
+    H --> I[Receive AuthChallengeSolution]
+    I --> K{Signature valid?}
+    K -- no --> Z
+    K -- yes --> J([Session started])
+```
+
+Auth challenges are generated from fresh random bytes plus a nanosecond timestamp. The server keeps the issued challenge only in the in-flight authentication state for that connection, then verifies the signature against the same canonical challenge payload.
+
+The authentication schema stores peer identity, not replay counters:
+
+- `program_client` stores the SDK client's public key, metadata binding, and timestamps.
+- `operator_client` stores the Operator public key and timestamps.
+- Neither table stores an authentication nonce, and challenge generation does not update either table.
+
+---
+
 ## Cryptography
 
 ### Authentication
-- **Signature scheme:** ed25519
+- **Client protocol:** ML-DSA
+
+### User-Agent Authentication
+
+Operator authentication supports multiple signature schemes because platform-provided "hardware-bound" keys do not expose a uniform algorithm across operating systems and hardware.
+
+- **Supported schemes:** ML-DSA
+- **Why:** Secure Enclave (MacOS) support them natively, on other platforms we could emulate while they roll-out
 
 ### Encryption at Rest
 - **Scheme:** Symmetric AEAD — currently **XChaCha20-Poly1305**
@@ -22,9 +80,21 @@ This document covers concrete technology choices and dependencies. For the archi
 ## Communication
 
 - **Protocol:** gRPC with Protocol Buffers
+- **Request/response matching:** multiplexed over a single bidirectional stream using per-connection request IDs
 - **Server identity distribution:** `ServerInfo` protobuf struct containing the TLS public key fingerprint
 - **Future consideration:** grpc-web lacks bidirectional stream support, so a browser-based wallet may require protojson over WebSocket
 
+### Request Multiplexing
+
+Both `client` and `operator` connections support multiple in-flight requests over one gRPC bidi stream.
+
+- Every request carries a monotonically increasing request ID
+- Every normal response echoes the request ID it corresponds to
+- Out-of-band server messages omit the response ID entirely
+- The server rejects already-seen request IDs at the transport adapter boundary before business logic sees the message
+
+This keeps request correlation entirely in transport/client connection code while leaving actor and domain handlers unaware of request IDs.
+
 ---
 
 ## EVM Policy Engine
@@ -45,6 +115,52 @@ The central abstraction is the `Policy` trait. Each implementation handles one s
 4. **Evaluate** — `Policy::evaluate` checks the decoded meaning against the grant's policy-specific constraints and returns any violations.
 5. **Record** — If `RunKind::Execution` and there are no violations, the engine writes to `evm_transaction_log` and calls `Policy::record_transaction` for any policy-specific logging (e.g., token transfer volume).
 
+The detailed branch structure is shown below:
+
+```mermaid
+flowchart TD
+    A[SDK Client sends sign transaction request] --> B[Server resolves wallet]
+    B --> C{Wallet exists?}
+
+    C -- No --> Z1[Return wallet not found error]
+    C -- Yes --> D[Check SDK client wallet visibility]
+
+    D --> E{Wallet visible to SDK client?}
+    E -- No --> F[Start wallet visibility voting flow]
+    F --> G{Vote approved?}
+    G -- No --> Z2[Return wallet access denied error]
+    G -- Yes --> H[Persist wallet visibility]
+    E -- Yes --> I[Classify transaction meaning]
+    H --> I
+
+    I --> J{Meaning supported?}
+    J -- No --> Z3[Return unsupported transaction error]
+    J -- Yes --> K[Find matching grant]
+
+    K --> L{Grant exists?}
+    L -- Yes --> M[Check grant limits]
+    L -- No --> N[Start execution or grant voting flow]
+
+    N --> O{Operator decision}
+    O -- Reject --> Z4[Return no matching grant error]
+    O -- Allow once --> M
+    O -- Create grant --> P[Create grant with user-selected limits]
+    P --> Q[Persist grant]
+    Q --> M
+
+    M --> R{Limits exceeded?}
+    R -- Yes --> Z5[Return evaluation error]
+    R -- No --> S[Record transaction in logs]
+    S --> T[Produce signature]
+    T --> U[Return signature to SDK client]
+
+    note1[Limit checks include volume, count, and gas constraints.]
+    note2[Grant lookup depends on classified meaning, such as ether transfer or token transfer.]
+
+    K -. uses .-> note2
+    M -. checks .-> note1
+```
+
 ### Policy Trait
 
 | Method | Purpose |
@@ -76,7 +192,7 @@ The central abstraction is the `Policy` trait. Each implementation handles one s
 Every grant has two layers:
 
 - **Shared (`evm_basic_grant`)** — wallet, chain, validity period, gas fee caps, transaction count rate limit. One row per grant regardless of type.
-- **Specific** — policy-owned tables (`evm_ether_transfer_grant`, `evm_token_transfer_grant`, etc.) holding type-specific configuration.
+- **Specific** — policy-owned tables (`evm_ether_transfer_grant`, `evm_token_transfer_grant`) holding type-specific configuration.
 
 `find_all_grants` uses a `#[diesel::auto_type]` base join between the specific and shared tables, then batch-loads related rows (targets, volume limits) in two additional queries to avoid N+1.
 
@@ -99,7 +215,6 @@ These are checked centrally in `check_shared_constraints` before policy evaluati
 - **Only EIP-1559 transactions are supported.** Legacy and EIP-2930 types are rejected outright.
 - **No opaque-calldata (unknown contract) grant type.** The architecture describes a category for unrecognised contracts, but no policy implements it yet. Any transaction that is not a plain ETH transfer or a known ERC-20 transfer is unconditionally rejected.
 - **Token registry is static.** Tokens are recognised only if they appear in the hard-coded `arbiter_tokens_registry` crate. There is no mechanism to register additional contracts at runtime.
-- **Nonce management is not implemented.** The architecture lists nonce deduplication as a core responsibility, but no nonce tracking or enforcement exists yet.
 
 ---
 
@@ -107,5 +222,5 @@ These are checked centrally in `check_shared_constraints` before policy evaluati
 
 The unsealed root key must be held in a hardened memory cell resistant to dumps, page swaps, and hibernation.
 
-- **Current:** Using the `memsafe` crate as an interim solution
-- **Planned:** Custom implementation based on `mlock` (Unix) and `VirtualProtect` (Windows)
+- **Current:** A dedicated memory-protection abstraction is in place, with `memsafe` used behind that abstraction today
+- **Planned:** Additional backends can be introduced behind the same abstraction, including a custom implementation based on `mlock` (Unix) and `VirtualProtect` (Windows)

mise.lock

@@ -1,69 +1,191 @@
+# @generated - this file is auto-generated by `mise lock` https://mise.jdx.dev/dev-tools/mise-lock.html
+
+[[tools.ast-grep]]
+version = "0.42.1"
+backend = "aqua:ast-grep/ast-grep"
+
+[tools.ast-grep."platforms.linux-arm64"]
+checksum = "sha256:3ba383839044cf9817929435f5ce0027f91d06931e8efb32d942e58d73d92be5"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.1/app-aarch64-unknown-linux-gnu.zip"
+url_api = "https://api.github.com/repos/ast-grep/ast-grep/releases/assets/388772218"
+
+[tools.ast-grep."platforms.linux-arm64-musl"]
+checksum = "sha256:3ba383839044cf9817929435f5ce0027f91d06931e8efb32d942e58d73d92be5"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.1/app-aarch64-unknown-linux-gnu.zip"
+
+[tools.ast-grep."platforms.linux-x64"]
+checksum = "sha256:5de8b87cba67fc8dc3e239d54b6484802ad745a7ae3de76be4fe89661dc52657"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.1/app-x86_64-unknown-linux-gnu.zip"
+url_api = "https://api.github.com/repos/ast-grep/ast-grep/releases/assets/388771275"
+
+[tools.ast-grep."platforms.linux-x64-musl"]
+checksum = "sha256:5de8b87cba67fc8dc3e239d54b6484802ad745a7ae3de76be4fe89661dc52657"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.1/app-x86_64-unknown-linux-gnu.zip"
+
+[tools.ast-grep."platforms.macos-arm64"]
+checksum = "sha256:c3961d8e8a4ee0ce2d0d98c7beeb168bb331cdc766b53630118a7b6c4fd39015"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.1/app-aarch64-apple-darwin.zip"
+url_api = "https://api.github.com/repos/ast-grep/ast-grep/releases/assets/388770234"
+
+[tools.ast-grep."platforms.macos-x64"]
+checksum = "sha256:a038965bfd7fe44257c771cdf8918dc3467dd8ec0eef673b8b14f639b144cdbd"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.1/app-x86_64-apple-darwin.zip"
+url_api = "https://api.github.com/repos/ast-grep/ast-grep/releases/assets/388770498"
+
+[tools.ast-grep."platforms.windows-x64"]
+checksum = "sha256:fe34f631bb24c08ad146f92ca2a92971a53d179461b509fd8d32dc863bff9f83"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.1/app-x86_64-pc-windows-msvc.zip"
+url_api = "https://api.github.com/repos/ast-grep/ast-grep/releases/assets/388771363"
+
 [[tools."cargo:cargo-audit"]]
 version = "0.22.1"
 backend = "cargo:cargo-audit"
 
-[[tools."cargo:cargo-features"]]
-version = "1.0.0"
-backend = "cargo:cargo-features"
+[[tools."cargo:cargo-edit"]]
+version = "0.13.10"
+backend = "cargo:cargo-edit"
 
 [[tools."cargo:cargo-features-manager"]]
-version = "0.11.1"
+version = "0.12.0"
 backend = "cargo:cargo-features-manager"
 
 [[tools."cargo:cargo-insta"]]
-version = "1.46.3"
+version = "1.47.2"
 backend = "cargo:cargo-insta"
 
+[[tools."cargo:cargo-mutants"]]
+version = "27.0.0"
+backend = "cargo:cargo-mutants"
+
 [[tools."cargo:cargo-nextest"]]
-version = "0.9.126"
+version = "0.9.133"
 backend = "cargo:cargo-nextest"
 
 [[tools."cargo:cargo-shear"]]
-version = "1.9.1"
+version = "1.13.4"
 backend = "cargo:cargo-shear"
 
 [[tools."cargo:cargo-vet"]]
 version = "0.10.2"
 backend = "cargo:cargo-vet"
 
-[[tools."cargo:diesel-cli"]]
-version = "2.3.6"
-backend = "cargo:diesel-cli"
-
-[tools."cargo:diesel-cli".options]
-default-features = "false"
-features = "sqlite,sqlite-bundled"
-
 [[tools."cargo:diesel_cli"]]
-version = "2.3.6"
+version = "2.3.7"
 backend = "cargo:diesel_cli"
 
 [tools."cargo:diesel_cli".options]
 default-features = "false"
 features = "sqlite,sqlite-bundled"
 
+[[tools."cargo:flutter_rust_bridge_codegen"]]
+version = "2.12.0"
+backend = "cargo:flutter_rust_bridge_codegen"
+
 [[tools.flutter]]
-version = "3.38.9-stable"
-backend = "asdf:flutter"
+version = "3.41.7-stable"
+backend = "http:flutter"
+
+[tools.flutter."platforms.linux-x64"]
+checksum = "sha256:f344d5057db52abc2a63cd3a7c7370957b7685d1fca5e5fbe2ce4dfe74657a79"
+url = "https://storage.googleapis.com/flutter_infra_release/releases/stable/linux/flutter_linux_3.41.7-stable.tar.xz"
+
+[tools.flutter."platforms.linux-x64-musl"]
+checksum = "sha256:f344d5057db52abc2a63cd3a7c7370957b7685d1fca5e5fbe2ce4dfe74657a79"
+url = "https://storage.googleapis.com/flutter_infra_release/releases/stable/linux/flutter_linux_3.41.7-stable.tar.xz"
+
+[tools.flutter."platforms.macos-arm64"]
+checksum = "sha256:2e3e6af44d1adccf695deff52e5e4c8beb10e5625066b27ad082b38b83ef805e"
+url = "https://storage.googleapis.com/flutter_infra_release/releases/stable/macos/flutter_macos_arm64_3.41.7-stable.zip"
+
+[tools.flutter."platforms.macos-x64"]
+checksum = "sha256:a0b9af49e6e1a6800f31a408b98c1d7bd51e98650a8b9ebcd77168b48c916ff0"
+url = "https://storage.googleapis.com/flutter_infra_release/releases/stable/macos/flutter_macos_3.41.7-stable.zip"
+
+[tools.flutter."platforms.windows-x64"]
+checksum = "sha256:de17b513b740a931c5dbc3f96b5a659c1612dfe6b5e1f910c5ad954a8bac17ee"
+url = "https://storage.googleapis.com/flutter_infra_release/releases/stable/windows/flutter_windows_3.41.7-stable.zip"
 
 [[tools.protoc]]
 version = "29.6"
 backend = "aqua:protocolbuffers/protobuf/protoc"
-"platforms.linux-arm64" = { checksum = "sha256:2594ff4fcae8cb57310d394d0961b236190ad9c5efbfdf1f597ea471d424fe79", url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-linux-aarch_64.zip"}
-"platforms.linux-x64" = { checksum = "sha256:48785a926e73ffa3f68e2f22b14e7b849620c7a1d36809ac9249a5495e280323", url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-linux-x86_64.zip"}
-"platforms.macos-arm64" = { checksum = "sha256:b9576b5fa1a1ef3fe13a8c91d9d8204b46545759bea5ae155cd6ba2ea4cdaeed", url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-osx-aarch_64.zip"}
-"platforms.macos-x64" = { checksum = "sha256:312f04713946921cc0187ef34df80241ddca1bab6f564c636885fd2cc90d3f88", url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-osx-x86_64.zip"}
-"platforms.windows-x64" = { checksum = "sha256:1ebd7c87baffb9f1c47169b640872bf5fb1e4408079c691af527be9561d8f6f7", url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-win64.zip"}
+
+[tools.protoc."platforms.linux-arm64"]
+checksum = "sha256:2594ff4fcae8cb57310d394d0961b236190ad9c5efbfdf1f597ea471d424fe79"
+url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-linux-aarch_64.zip"
+url_api = "https://api.github.com/repos/protocolbuffers/protobuf/releases/assets/350795076"
+
+[tools.protoc."platforms.linux-arm64-musl"]
+checksum = "sha256:2594ff4fcae8cb57310d394d0961b236190ad9c5efbfdf1f597ea471d424fe79"
+url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-linux-aarch_64.zip"
+url_api = "https://api.github.com/repos/protocolbuffers/protobuf/releases/assets/350795076"
+
+[tools.protoc."platforms.linux-x64"]
+checksum = "sha256:48785a926e73ffa3f68e2f22b14e7b849620c7a1d36809ac9249a5495e280323"
+url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-linux-x86_64.zip"
+url_api = "https://api.github.com/repos/protocolbuffers/protobuf/releases/assets/350795083"
+
+[tools.protoc."platforms.linux-x64-musl"]
+checksum = "sha256:48785a926e73ffa3f68e2f22b14e7b849620c7a1d36809ac9249a5495e280323"
+url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-linux-x86_64.zip"
+url_api = "https://api.github.com/repos/protocolbuffers/protobuf/releases/assets/350795083"
+
+[tools.protoc."platforms.macos-arm64"]
+checksum = "sha256:b9576b5fa1a1ef3fe13a8c91d9d8204b46545759bea5ae155cd6ba2ea4cdaeed"
+url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-osx-aarch_64.zip"
+url_api = "https://api.github.com/repos/protocolbuffers/protobuf/releases/assets/350795082"
+
+[tools.protoc."platforms.macos-x64"]
+checksum = "sha256:312f04713946921cc0187ef34df80241ddca1bab6f564c636885fd2cc90d3f88"
+url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-osx-x86_64.zip"
+url_api = "https://api.github.com/repos/protocolbuffers/protobuf/releases/assets/350795085"
+
+[tools.protoc."platforms.windows-x64"]
+checksum = "sha256:1ebd7c87baffb9f1c47169b640872bf5fb1e4408079c691af527be9561d8f6f7"
+url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-win64.zip"
+url_api = "https://api.github.com/repos/protocolbuffers/protobuf/releases/assets/350795088"
 
 [[tools.python]]
-version = "3.14.3"
+version = "3.14.4"
 backend = "core:python"
-"platforms.linux-arm64" = { checksum = "sha256:be0f4dc2932f762292b27d46ea7d3e8e66ddf3969a5eb0254a229015ed402625", url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260303/cpython-3.14.3+20260303-aarch64-unknown-linux-gnu-install_only_stripped.tar.gz"}
-"platforms.linux-x64" = { checksum = "sha256:0a73413f89efd417871876c9accaab28a9d1e3cd6358fbfff171a38ec99302f0", url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260303/cpython-3.14.3+20260303-x86_64-unknown-linux-gnu-install_only_stripped.tar.gz"}
-"platforms.macos-arm64" = { checksum = "sha256:4703cdf18b26798fde7b49b6b66149674c25f97127be6a10dbcf29309bdcdcdb", url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260303/cpython-3.14.3+20260303-aarch64-apple-darwin-install_only_stripped.tar.gz"}
-"platforms.macos-x64" = { checksum = "sha256:76f1cc26e3d262eae8ca546a93e8bded10cf0323613f7e246fea2e10a8115eb7", url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260303/cpython-3.14.3+20260303-x86_64-apple-darwin-install_only_stripped.tar.gz"}
-"platforms.windows-x64" = { checksum = "sha256:950c5f21a015c1bdd1337f233456df2470fab71e4d794407d27a84cb8b9909a0", url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260303/cpython-3.14.3+20260303-x86_64-pc-windows-msvc-install_only_stripped.tar.gz"}
+
+[tools.python."platforms.linux-arm64"]
+checksum = "sha256:b8b597fdb2f8dccdc502c11947b60a4b65eb6bce79cfa60c7ccf9b6e8352c60a"
+url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260414/cpython-3.14.4+20260414-aarch64-unknown-linux-gnu-install_only_stripped.tar.gz"
+provenance = "github-attestations"
+
+[tools.python."platforms.linux-arm64-musl"]
+checksum = "sha256:a10687b226e0941632569836bc1d8fa6353a8e3e8424316467ca9cdf220b983d"
+url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260414/cpython-3.14.4+20260414-aarch64-unknown-linux-musl-install_only_stripped.tar.gz"
+provenance = "github-attestations"
+
+[tools.python."platforms.linux-x64"]
+checksum = "sha256:fe9a9c32d13870af632cbac3dfc7528ae53597e94472aa4c7d6a42e8166136cd"
+url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260414/cpython-3.14.4+20260414-x86_64-unknown-linux-gnu-install_only_stripped.tar.gz"
+provenance = "github-attestations"
+
+[tools.python."platforms.linux-x64-musl"]
+checksum = "sha256:d6005226cd24e780630626232c7a63243d4885fdf975dcf930a0758a0759ce14"
+url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260414/cpython-3.14.4+20260414-x86_64-unknown-linux-musl-install_only_stripped.tar.gz"
+provenance = "github-attestations"
+
+[tools.python."platforms.macos-arm64"]
+checksum = "sha256:6f304f4ec30854611f23316578302235fb517cd970519ecdd11a8c4db87fd843"
+url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260414/cpython-3.14.4+20260414-aarch64-apple-darwin-install_only_stripped.tar.gz"
+provenance = "github-attestations"
+
+[tools.python."platforms.macos-x64"]
+checksum = "sha256:d51250a32fa5d9f0799c7bcb71720c27b10a3afd4a7de288120f96085d508a5a"
+url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260414/cpython-3.14.4+20260414-x86_64-apple-darwin-install_only_stripped.tar.gz"
+provenance = "github-attestations"
+
+[tools.python."platforms.windows-x64"]
+checksum = "sha256:a976991dcd085c1bb5d9a8084823a6bc8b7f9b079d8c432574a6ddd68c3a6fe1"
+url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260414/cpython-3.14.4+20260414-x86_64-pc-windows-msvc-install_only_stripped.tar.gz"
+provenance = "github-attestations"
 
 [[tools.rust]]
-version = "1.93.0"
+version = "1.95.0"
 backend = "core:rust"
+
+[tools.rust.options]
+components = "clippy,rust-analyzer"

mise.toml

@@ -1,12 +1,26 @@
 [tools]
-"cargo:diesel_cli" = { version = "2.3.6", features = "sqlite,sqlite-bundled", default-features = false }
+"cargo:diesel_cli" = { version = "2.3.7", features = "sqlite,sqlite-bundled", default-features = "false" }
 "cargo:cargo-audit" = "0.22.1"
 "cargo:cargo-vet" = "0.10.2"
-flutter = "3.38.9-stable"
+flutter = "3.41.7-stable"
 protoc = "29.6"
-"rust" = {version = "1.93.0", components = "clippy"}
-"cargo:cargo-features-manager" = "0.11.1"
-"cargo:cargo-nextest" = "0.9.126"
+rust = { version = "1.95.0", components = "clippy,rust-analyzer" }
+"cargo:cargo-features-manager" = "0.12.0"
+"cargo:cargo-nextest" = "0.9.133"
 "cargo:cargo-shear" = "latest"
-"cargo:cargo-insta" = "1.46.3"
-python = "3.14.3"
+"cargo:cargo-insta" = "1.47.2"
+python = "3.14.4"
+ast-grep = "0.42.1"
+"cargo:cargo-edit" = "0.13.10"
+"cargo:cargo-mutants" = "27.0.0"
+"cargo:flutter_rust_bridge_codegen" = "2.12.0"
+
+[tasks.codegen]
+sources = ['protobufs/*.proto', 'protobufs/**/*.proto']
+outputs = ['useragent/lib/proto/**']
+run = '''
+dart pub global activate protoc_plugin && \
+protoc --dart_out=grpc:useragent/lib/proto --proto_path=protobufs/ $(find protobufs -name '*.proto' | sort)
+'''
+
+[tasks.generate_schema]

protobufs/arbiter.proto

@@ -3,7 +3,7 @@ syntax = "proto3";
 package arbiter;
 
 import "client.proto";
-import "user_agent.proto";
+import "operator.proto";
 
 message ServerInfo {
   string version = 1;
@@ -12,5 +12,5 @@ message ServerInfo {
 
 service ArbiterService {
   rpc Client(stream arbiter.client.ClientRequest) returns (stream arbiter.client.ClientResponse);
-  rpc UserAgent(stream arbiter.user_agent.UserAgentRequest) returns (stream arbiter.user_agent.UserAgentResponse);
+  rpc Operator(stream arbiter.operator.OperatorRequest) returns (stream arbiter.operator.OperatorResponse);
 }

protobufs/client.proto

@@ -2,37 +2,24 @@ syntax = "proto3";
 
 package arbiter.client;
 
-import "evm.proto";
-
-message AuthChallengeRequest {
-  bytes pubkey = 1;
-}
-
-message AuthChallenge {
-  bytes pubkey = 1;
-  int32 nonce = 2;
-}
-
-message AuthChallengeSolution {
-  bytes signature = 1;
-}
-
-message AuthOk {}
+import "client/auth.proto";
+import "client/evm.proto";
+import "client/vault.proto";
 
 message ClientRequest {
+  int32 request_id = 4;
   oneof payload {
-    AuthChallengeRequest auth_challenge_request = 1;
-    AuthChallengeSolution auth_challenge_solution = 2;
-    arbiter.evm.EvmSignTransactionRequest evm_sign_transaction = 3;
-    arbiter.evm.EvmAnalyzeTransactionRequest evm_analyze_transaction = 4;
+    auth.Request auth = 1;
+    vault.Request vault = 2;
+    evm.Request evm = 3;
   }
 }
 
 message ClientResponse {
+  optional int32 request_id = 7;
   oneof payload {
-    AuthChallenge auth_challenge = 1;
-    AuthOk auth_ok = 2;
-    arbiter.evm.EvmSignTransactionResponse evm_sign_transaction = 3;
-    arbiter.evm.EvmAnalyzeTransactionResponse evm_analyze_transaction = 4;
+    auth.Response auth = 1;
+    vault.Response vault = 2;
+    evm.Response evm = 3;
   }
 }

protobufs/client/auth.proto

@@ -0,0 +1,43 @@
+syntax = "proto3";
+
+package arbiter.client.auth;
+
+import "shared/client.proto";
+
+message AuthChallengeRequest {
+  bytes pubkey = 1;
+  arbiter.shared.ClientInfo client_info = 2;
+}
+
+message AuthChallenge {
+  uint64 timestamp_nanos = 1;
+  bytes random = 2;
+}
+
+message AuthChallengeSolution {
+  bytes signature = 1;
+}
+
+enum AuthResult {
+  AUTH_RESULT_UNSPECIFIED = 0;
+  AUTH_RESULT_SUCCESS = 1;
+  AUTH_RESULT_INVALID_KEY = 2;
+  AUTH_RESULT_INVALID_SIGNATURE = 3;
+  AUTH_RESULT_APPROVAL_DENIED = 4;
+  AUTH_RESULT_NO_OPERATORS_ONLINE = 5;
+  AUTH_RESULT_INTERNAL = 6;
+}
+
+message Request {
+  oneof payload {
+    AuthChallengeRequest challenge_request = 1;
+    AuthChallengeSolution challenge_solution = 2;
+  }
+}
+
+message Response {
+  oneof payload {
+    AuthChallenge challenge = 1;
+    AuthResult result = 2;
+  }
+}

protobufs/client/evm.proto

@@ -0,0 +1,19 @@
+syntax = "proto3";
+
+package arbiter.client.evm;
+
+import "evm.proto";
+
+message Request {
+  oneof payload {
+    arbiter.evm.EvmSignTransactionRequest sign_transaction = 1;
+    arbiter.evm.EvmAnalyzeTransactionRequest analyze_transaction = 2;
+  }
+}
+
+message Response {
+  oneof payload {
+    arbiter.evm.EvmSignTransactionResponse sign_transaction = 1;
+    arbiter.evm.EvmAnalyzeTransactionResponse analyze_transaction = 2;
+  }
+}

protobufs/client/vault.proto

@@ -0,0 +1,18 @@
+syntax = "proto3";
+
+package arbiter.client.vault;
+
+import "google/protobuf/empty.proto";
+import "shared/vault.proto";
+
+message Request {
+  oneof payload {
+    google.protobuf.Empty query_state = 1;
+  }
+}
+
+message Response {
+  oneof payload {
+    arbiter.shared.VaultState state = 1;
+  }
+}

protobufs/evm.proto

@@ -4,6 +4,7 @@ package arbiter.evm;
 
 import "google/protobuf/empty.proto";
 import "google/protobuf/timestamp.proto";
+import "shared/evm.proto";
 
 enum EvmError {
   EVM_ERROR_UNSPECIFIED = 0;
@@ -12,7 +13,8 @@ enum EvmError {
 }
 
 message WalletEntry {
-  bytes address = 1; // 20-byte Ethereum address
+  int32 id = 1;
+  bytes address = 2; // 20-byte Ethereum address
 }
 
 message WalletList {
@@ -46,7 +48,7 @@ message VolumeRateLimit {
 }
 
 message SharedSettings {
-  int32 wallet_id = 1;
+  int32 wallet_access_id = 1;
   uint64 chain_id = 2;
   optional google.protobuf.Timestamp valid_from = 3;
   optional google.protobuf.Timestamp valid_until = 4;
@@ -73,75 +75,10 @@ message SpecificGrant {
   }
 }
 
-message EtherTransferMeaning {
-  bytes to = 1; // 20-byte Ethereum address
-  bytes value = 2; // U256 as big-endian bytes
-}
-
-message TokenInfo {
-  string symbol = 1;
-  bytes address = 2; // 20-byte Ethereum address
-  uint64 chain_id = 3;
-}
-
-// Mirror of token_transfers::Meaning
-message TokenTransferMeaning {
-  TokenInfo token = 1;
-  bytes to = 2; // 20-byte Ethereum address
-  bytes value = 3; // U256 as big-endian bytes
-}
-
-// Mirror of policies::SpecificMeaning
-message SpecificMeaning {
-  oneof meaning {
-    EtherTransferMeaning ether_transfer = 1;
-    TokenTransferMeaning token_transfer = 2;
-  }
-}
-
-// --- Eval error types ---
-message GasLimitExceededViolation {
-  optional bytes max_gas_fee_per_gas = 1; // U256 as big-endian bytes
-  optional bytes max_priority_fee_per_gas = 2; // U256 as big-endian bytes
-}
-
-message EvalViolation {
-  oneof kind {
-    bytes invalid_target = 1; // 20-byte Ethereum address
-    GasLimitExceededViolation gas_limit_exceeded = 2;
-    google.protobuf.Empty rate_limit_exceeded = 3;
-    google.protobuf.Empty volumetric_limit_exceeded = 4;
-    google.protobuf.Empty invalid_time = 5;
-    google.protobuf.Empty invalid_transaction_type = 6;
-  }
-}
-
-// Transaction was classified but no grant covers it
-message NoMatchingGrantError {
-  SpecificMeaning meaning = 1;
-}
-
-// Transaction was classified and a grant was found, but constraints were violated
-message PolicyViolationsError {
-  SpecificMeaning meaning = 1;
-  repeated EvalViolation violations = 2;
-}
-
-// top-level error returned when transaction evaluation fails
-message TransactionEvalError {
-  oneof kind {
-    google.protobuf.Empty contract_creation_not_supported = 1;
-    google.protobuf.Empty unsupported_transaction_type = 2;
-    NoMatchingGrantError no_matching_grant = 3;
-    PolicyViolationsError policy_violations = 4;
-  }
-}
-
-// --- UserAgent grant management ---
+// --- Operator grant management ---
 message EvmGrantCreateRequest {
-  int32 client_id = 1;
-  SharedSettings shared = 2;
-  SpecificGrant specific = 3;
+  SharedSettings shared = 1;
+  SpecificGrant specific = 2;
 }
 
 message EvmGrantCreateResponse {
@@ -165,13 +102,13 @@ message EvmGrantDeleteResponse {
 // Basic grant info returned in grant listings
 message GrantEntry {
   int32 id = 1;
-  int32 client_id = 2;
+  int32 wallet_access_id = 2;
   SharedSettings shared = 3;
   SpecificGrant specific = 4;
 }
 
 message EvmGrantListRequest {
-  optional int32 wallet_id = 1;
+  optional int32 wallet_access_id = 1;
 }
 
 message EvmGrantListResponse {
@@ -197,7 +134,7 @@ message EvmSignTransactionRequest {
 message EvmSignTransactionResponse {
   oneof result {
     bytes signature = 1; // 65-byte signature: r[32] || s[32] || v[1]
-    TransactionEvalError eval_error = 2;
+    arbiter.shared.evm.TransactionEvalError eval_error = 2;
     EvmError error = 3;
   }
 }
@@ -209,8 +146,8 @@ message EvmAnalyzeTransactionRequest {
 
 message EvmAnalyzeTransactionResponse {
   oneof result {
-    SpecificMeaning meaning = 1;
-    TransactionEvalError eval_error = 2;
+    arbiter.shared.evm.SpecificMeaning meaning = 1;
+    arbiter.shared.evm.TransactionEvalError eval_error = 2;
     EvmError error = 3;
   }
 }

protobufs/operator.proto

@@ -0,0 +1,31 @@
+syntax = "proto3";
+
+package arbiter.operator;
+
+import "operator/auth.proto";
+import "operator/evm.proto";
+import "operator/governance.proto";
+import "operator/sdk_client.proto";
+import "operator/vault/vault.proto";
+
+message OperatorRequest {
+  int32 id = 16;
+  oneof payload {
+    auth.Request            auth        = 1;
+    vault.Request           vault       = 2;
+    evm.Request             evm         = 3;
+    sdk_client.Request      sdk_client  = 4;
+    governance.Request      governance  = 5;
+  }
+}
+
+message OperatorResponse {
+  optional int32 id = 16;
+  oneof payload {
+    auth.Response           auth        = 1;
+    vault.Response          vault       = 2;
+    evm.Response            evm         = 3;
+    sdk_client.Response     sdk_client  = 4;
+    governance.Response     governance  = 5;
+  }
+}

protobufs/operator/auth.proto

@@ -0,0 +1,41 @@
+syntax = "proto3";
+
+package arbiter.operator.auth;
+
+message AuthChallengeRequest {
+  bytes pubkey = 1;
+  optional string bootstrap_token = 2;
+}
+
+message AuthChallenge {
+  uint64 timestamp_nanos = 1;
+  bytes random = 2;
+}
+
+message AuthChallengeSolution {
+  bytes signature = 1;
+}
+
+enum AuthResult {
+  AUTH_RESULT_UNSPECIFIED = 0;
+  AUTH_RESULT_SUCCESS = 1;
+  AUTH_RESULT_INVALID_KEY = 2;
+  AUTH_RESULT_INVALID_SIGNATURE = 3;
+  AUTH_RESULT_BOOTSTRAP_REQUIRED = 4;
+  AUTH_RESULT_TOKEN_INVALID = 5;
+  AUTH_RESULT_INTERNAL = 6;
+}
+
+message Request {
+  oneof payload {
+    AuthChallengeRequest challenge_request = 1;
+    AuthChallengeSolution challenge_solution = 2;
+  }
+}
+
+message Response {
+  oneof payload {
+    AuthChallenge challenge = 1;
+    AuthResult result = 2;
+  }
+}

protobufs/operator/evm.proto

@@ -0,0 +1,33 @@
+syntax = "proto3";
+
+package arbiter.operator.evm;
+
+import "evm.proto";
+import "google/protobuf/empty.proto";
+
+message SignTransactionRequest {
+  int32 client_id = 1;
+  arbiter.evm.EvmSignTransactionRequest request = 2;
+}
+
+message Request {
+  oneof payload {
+    google.protobuf.Empty wallet_create = 1;
+    google.protobuf.Empty wallet_list = 2;
+    arbiter.evm.EvmGrantCreateRequest grant_create = 3;
+    arbiter.evm.EvmGrantDeleteRequest grant_delete = 4;
+    arbiter.evm.EvmGrantListRequest grant_list = 5;
+    SignTransactionRequest sign_transaction = 6;
+  }
+}
+
+message Response {
+  oneof payload {
+    arbiter.evm.WalletCreateResponse wallet_create = 1;
+    arbiter.evm.WalletListResponse wallet_list = 2;
+    arbiter.evm.EvmGrantCreateResponse grant_create = 3;
+    arbiter.evm.EvmGrantDeleteResponse grant_delete = 4;
+    arbiter.evm.EvmGrantListResponse grant_list = 5;
+    arbiter.evm.EvmSignTransactionResponse sign_transaction = 6;
+  }
+}

protobufs/operator/governance.proto

@@ -0,0 +1,131 @@
+syntax = "proto3";
+
+package arbiter.operator.governance;
+
+import "google/protobuf/empty.proto";
+
+message Request {
+  oneof payload {
+    CreateProposalRequest create = 1;
+    CastVoteRequest       vote   = 2;
+    QueryPendingRequest   query  = 3;
+  }
+}
+
+message CreateProposalRequest {
+  oneof kind {
+    ApproveSdkClientPayload         approve_sdk_client          = 1;
+    GrantWalletAccessPayload        grant_wallet_access         = 2;
+    ReplaceOperatorPayload          replace_operator            = 3;
+    google.protobuf.Empty           trigger_rekey               = 4;
+    ApprovePersistentGrantPayload   approve_persistent_grant    = 5;
+    ApproveOneOffTransactionPayload approve_one_off_transaction = 6;
+  }
+  optional uint32 ttl_secs = 7;
+}
+
+message ReplaceOperatorPayload {
+  int32 old_operator_id = 1;
+  bytes new_pubkey      = 2;
+}
+
+message ApproveSdkClientPayload {
+  int32 client_id = 1;
+}
+
+message GrantWalletAccessPayload {
+  int32 wallet_id = 1;
+  int32 client_id = 2;
+}
+
+message CastVoteRequest {
+  int32 proposal_id = 1;
+  bool  approve     = 2;
+  bytes signature   = 3;
+}
+
+message QueryPendingRequest {}
+
+message Response {
+  oneof payload {
+    CreateProposalResponse created = 1;
+    VoteResponse           voted   = 2;
+    QueryPendingResponse   pending = 3;
+  }
+}
+
+message CreateProposalResponse {
+  int32 proposal_id = 1;
+}
+
+message VoteResponse {
+  VoteOutcome outcome = 1;
+}
+
+enum VoteOutcome {
+  VOTE_OUTCOME_UNSPECIFIED = 0;
+  VOTE_OUTCOME_PENDING     = 1;
+  VOTE_OUTCOME_APPROVED    = 2;
+  VOTE_OUTCOME_REJECTED    = 3;
+}
+
+message ProposalSummary {
+  int32  id            = 1;
+  string kind          = 2;
+  int32  initiator_id  = 3;
+  int64  expires_at    = 4;
+  int64  approve_count = 5;
+  int64  reject_count  = 6;
+}
+
+message QueryPendingResponse {
+  repeated ProposalSummary proposals = 1;
+}
+
+message TransactionRateLimitProto {
+  uint32 count       = 1;
+  int64  window_secs = 2;
+}
+
+message VolumeLimitProto {
+  bytes max_volume  = 1;
+  int64 window_secs = 2;
+}
+
+message EtherTransferSpecProto {
+  repeated bytes   targets = 1;
+  VolumeLimitProto limit   = 2;
+}
+
+message TokenTransferSpecProto {
+  bytes                     token_contract = 1;
+  optional bytes            target         = 2;
+  repeated VolumeLimitProto volume_limits  = 3;
+}
+
+message ApproveOneOffTransactionPayload {
+  int32  client_id                = 1;
+  bytes  wallet_address           = 2;
+  uint64 chain_id                 = 3;
+  uint64 nonce                    = 4;
+  uint64 gas_limit                = 5;
+  bytes  max_fee_per_gas          = 6;
+  bytes  max_priority_fee_per_gas = 7;
+  bytes  to                       = 8;
+  bytes  value                    = 9;
+  bytes  input                    = 10;
+}
+
+message ApprovePersistentGrantPayload {
+  int32                              wallet_access_id         = 1;
+  uint64                             chain_id                 = 2;
+  optional int64                     valid_from_secs          = 3;
+  optional int64                     valid_until_secs         = 4;
+  optional bytes                     max_gas_fee_per_gas      = 5;
+  optional bytes                     max_priority_fee_per_gas = 6;
+  optional TransactionRateLimitProto rate_limit               = 7;
+  oneof specific {
+    EtherTransferSpecProto ether_transfer = 8;
+    TokenTransferSpecProto token_transfer = 9;
+  }
+}

protobufs/operator/sdk_client.proto

@@ -0,0 +1,100 @@
+syntax = "proto3";
+
+package arbiter.operator.sdk_client;
+
+import "shared/client.proto";
+import "google/protobuf/empty.proto";
+
+enum Error {
+  ERROR_UNSPECIFIED = 0;
+  ERROR_ALREADY_EXISTS = 1;
+  ERROR_NOT_FOUND = 2;
+  ERROR_HAS_RELATED_DATA = 3; // hard-delete blocked by FK (client has grants or transaction logs)
+  ERROR_INTERNAL = 4;
+}
+
+message RevokeRequest {
+  int32 client_id = 1;
+}
+
+message Entry {
+  int32 id = 1;
+  bytes pubkey = 2;
+  arbiter.shared.ClientInfo info = 3;
+  int32 created_at = 4;
+}
+
+message List {
+  repeated Entry clients = 1;
+}
+
+message RevokeResponse {
+  oneof result {
+    google.protobuf.Empty ok = 1;
+    Error error = 2;
+  }
+}
+
+message ListResponse {
+  oneof result {
+    List clients = 1;
+    Error error = 2;
+  }
+}
+
+message ConnectionRequest {
+  bytes pubkey = 1;
+  arbiter.shared.ClientInfo info = 2;
+}
+
+message ConnectionResponse {
+  bool approved = 1;
+  bytes pubkey = 2;
+}
+
+message ConnectionCancel {
+  bytes pubkey = 1;
+}
+
+message WalletAccess {
+  int32 wallet_id = 1;
+  int32 sdk_client_id = 2;
+}
+
+message WalletAccessEntry {
+  int32 id = 1;
+  WalletAccess access = 2;
+}
+
+message GrantWalletAccess {
+  repeated WalletAccess accesses = 1;
+}
+
+message RevokeWalletAccess {
+  repeated int32 accesses = 1;
+}
+
+message ListWalletAccessResponse {
+  repeated WalletAccessEntry accesses = 1;
+}
+
+message Request {
+  oneof payload {
+    ConnectionResponse connection_response = 1;
+    RevokeRequest revoke = 2;
+    google.protobuf.Empty list = 3;
+    GrantWalletAccess grant_wallet_access = 4;
+    RevokeWalletAccess revoke_wallet_access = 5;
+    google.protobuf.Empty list_wallet_access = 6;
+  }
+}
+
+message Response {
+  oneof payload {
+    ConnectionRequest connection_request = 1;
+    ConnectionCancel connection_cancel = 2;
+    RevokeResponse revoke = 3;
+    ListResponse list = 4;
+    ListWalletAccessResponse list_wallet_access = 5;
+  }
+}

protobufs/operator/vault/bootstrap.proto

@@ -0,0 +1,43 @@
+syntax = "proto3";
+
+package arbiter.operator.vault.bootstrap;
+
+message BootstrapEncryptedKey {
+  bytes nonce = 1;
+  bytes ciphertext = 2;
+  bytes associated_data = 3;
+}
+
+message DeclareCommittee {
+  uint32 count          = 1;
+  uint32 recovery_count = 2;
+}
+
+message ContributePassphrase {
+  bytes passphrase = 1;
+}
+
+message ContributeRecoveryPassphrase {
+  bytes passphrase = 1;
+}
+
+enum BootstrapResult {
+  BOOTSTRAP_RESULT_UNSPECIFIED = 0;
+  BOOTSTRAP_RESULT_SUCCESS = 1;
+  BOOTSTRAP_RESULT_ALREADY_BOOTSTRAPPED = 2;
+  BOOTSTRAP_RESULT_INVALID_KEY = 3;
+  BOOTSTRAP_RESULT_AWAITING_CONTRIBUTIONS = 4;
+}
+
+message Request {
+  oneof payload {
+    BootstrapEncryptedKey        encrypted_key                    = 2;
+    DeclareCommittee             declare_committee                = 3;
+    ContributePassphrase         contribute_passphrase            = 4;
+    ContributeRecoveryPassphrase contribute_recovery_passphrase   = 5;
+  }
+}
+
+message Response {
+  BootstrapResult result = 1;
+}

protobufs/operator/vault/rekey.proto

@@ -0,0 +1,29 @@
+syntax = "proto3";
+
+package arbiter.operator.vault.rekey;
+
+message ContributePassphrase {
+  bytes passphrase = 1;
+}
+
+message ContributeRecoveryPassphrase {
+  bytes passphrase = 1;
+}
+
+enum RekeyResult {
+  REKEY_RESULT_UNSPECIFIED            = 0;
+  REKEY_RESULT_SUCCESS                = 1;
+  REKEY_RESULT_AWAITING_CONTRIBUTIONS = 2;
+  REKEY_RESULT_NOT_IN_PROGRESS        = 3;
+}
+
+message Request {
+  oneof payload {
+    ContributePassphrase         contribute_passphrase          = 1;
+    ContributeRecoveryPassphrase contribute_recovery_passphrase = 2;
+  }
+}
+
+message Response {
+  RekeyResult result = 1;
+}

protobufs/operator/vault/unseal.proto

@@ -0,0 +1,48 @@
+syntax = "proto3";
+
+package arbiter.operator.vault.unseal;
+
+message UnsealStart {
+  bytes client_pubkey = 1;
+}
+
+message UnsealStartResponse {
+  bytes server_pubkey = 1;
+}
+message UnsealEncryptedKey {
+  bytes nonce = 1;
+  bytes ciphertext = 2;
+  bytes associated_data = 3;
+}
+
+message ContributePassphrase {
+  bytes passphrase = 1;
+}
+
+message ContributeRecoveryPassphrase {
+  bytes passphrase = 1;
+}
+
+enum UnsealResult {
+  UNSEAL_RESULT_UNSPECIFIED = 0;
+  UNSEAL_RESULT_SUCCESS = 1;
+  UNSEAL_RESULT_INVALID_KEY = 2;
+  UNSEAL_RESULT_UNBOOTSTRAPPED = 3;
+  UNSEAL_RESULT_AWAITING_CONTRIBUTIONS = 4;
+}
+
+message Request {
+  oneof payload {
+    UnsealStart                  start                          = 1;
+    UnsealEncryptedKey           encrypted_key                  = 2;
+    ContributePassphrase         contribute_passphrase          = 3;
+    ContributeRecoveryPassphrase contribute_recovery_passphrase = 4;
+  }
+}
+
+message Response {
+  oneof payload {
+    UnsealStartResponse start = 1;
+    UnsealResult result = 2;
+  }
+}

protobufs/operator/vault/vault.proto

@@ -0,0 +1,27 @@
+syntax = "proto3";
+
+package arbiter.operator.vault;
+
+import "google/protobuf/empty.proto";
+import "shared/vault.proto";
+import "operator/vault/bootstrap.proto";
+import "operator/vault/rekey.proto";
+import "operator/vault/unseal.proto";
+
+message Request {
+  oneof payload {
+    google.protobuf.Empty query_state = 1;
+    unseal.Request        unseal      = 2;
+    bootstrap.Request     bootstrap   = 3;
+    rekey.Request         rekey       = 4;
+  }
+}
+
+message Response {
+  oneof payload {
+    arbiter.shared.VaultState state     = 1;
+    unseal.Response           unseal    = 2;
+    bootstrap.Response        bootstrap = 3;
+    rekey.Response            rekey     = 4;
+  }
+}

protobufs/shared/client.proto

@@ -0,0 +1,9 @@
+syntax = "proto3";
+
+package arbiter.shared;
+
+message ClientInfo {
+  string name = 1;
+  optional string description = 2;
+  optional string version = 3;
+}

protobufs/shared/evm.proto

@@ -0,0 +1,74 @@
+syntax = "proto3";
+
+package arbiter.shared.evm;
+
+import "google/protobuf/empty.proto";
+
+message EtherTransferMeaning {
+  bytes to = 1; // 20-byte Ethereum address
+  bytes value = 2; // U256 as big-endian bytes
+}
+
+message TokenInfo {
+  string symbol = 1;
+  bytes address = 2; // 20-byte Ethereum address
+  uint64 chain_id = 3;
+}
+
+// Mirror of token_transfers::Meaning
+message TokenTransferMeaning {
+  TokenInfo token = 1;
+  bytes to = 2; // 20-byte Ethereum address
+  bytes value = 3; // U256 as big-endian bytes
+}
+
+// Mirror of policies::SpecificMeaning
+message SpecificMeaning {
+  oneof meaning {
+    EtherTransferMeaning ether_transfer = 1;
+    TokenTransferMeaning token_transfer = 2;
+  }
+}
+
+message GasLimitExceededViolation {
+  optional bytes max_gas_fee_per_gas = 1; // U256 as big-endian bytes
+  optional bytes max_priority_fee_per_gas = 2; // U256 as big-endian bytes
+}
+
+message EvalViolation {
+  message ChainIdMismatch {
+    uint64 expected = 1;
+    uint64 actual = 2;
+  }
+  oneof kind {
+    bytes invalid_target = 1; // 20-byte Ethereum address
+    GasLimitExceededViolation gas_limit_exceeded = 2;
+    google.protobuf.Empty rate_limit_exceeded = 3;
+    google.protobuf.Empty volumetric_limit_exceeded = 4;
+    google.protobuf.Empty invalid_time = 5;
+    google.protobuf.Empty invalid_transaction_type = 6;
+
+    ChainIdMismatch chain_id_mismatch = 7;
+  }
+}
+
+// Transaction was classified but no grant covers it
+message NoMatchingGrantError {
+  SpecificMeaning meaning = 1;
+}
+
+// Transaction was classified and a grant was found, but constraints were violated
+message PolicyViolationsError {
+  SpecificMeaning meaning = 1;
+  repeated EvalViolation violations = 2;
+}
+
+// top-level error returned when transaction evaluation fails
+message TransactionEvalError {
+  oneof kind {
+    google.protobuf.Empty contract_creation_not_supported = 1;
+    google.protobuf.Empty unsupported_transaction_type = 2;
+    NoMatchingGrantError no_matching_grant = 3;
+    PolicyViolationsError policy_violations = 4;
+  }
+}

protobufs/shared/vault.proto

@@ -0,0 +1,12 @@
+syntax = "proto3";
+
+package arbiter.shared;
+
+enum VaultState {
+  VAULT_STATE_UNSPECIFIED = 0;
+  VAULT_STATE_UNBOOTSTRAPPED = 1;
+  VAULT_STATE_BOOSTRAPPING = 2;
+  VAULT_STATE_SEALED = 3;
+  VAULT_STATE_UNSEALED = 4;
+  VAULT_STATE_ERROR = 5;
+}

protobufs/user_agent.proto

@@ -1,79 +0,0 @@
-syntax = "proto3";
-
-package arbiter.user_agent;
-
-import "google/protobuf/empty.proto";
-import "evm.proto";
-
-message AuthChallengeRequest {
-  bytes pubkey = 1;
-  optional string bootstrap_token = 2;
-}
-
-message AuthChallenge {
-  bytes pubkey = 1;
-  int32 nonce = 2;
-}
-
-message AuthChallengeSolution {
-  bytes signature = 1;
-}
-
-message AuthOk {}
-
-message UnsealStart {
-  bytes client_pubkey = 1;
-}
-
-message UnsealStartResponse {
-  bytes server_pubkey = 1;
-}
-message UnsealEncryptedKey {
-  bytes nonce = 1;
-  bytes ciphertext = 2;
-  bytes associated_data = 3;
-}
-
-enum UnsealResult {
-  UNSEAL_RESULT_UNSPECIFIED = 0;
-  UNSEAL_RESULT_SUCCESS = 1;
-  UNSEAL_RESULT_INVALID_KEY = 2;
-  UNSEAL_RESULT_UNBOOTSTRAPPED = 3;
-}
-
-enum VaultState {
-  VAULT_STATE_UNSPECIFIED = 0;
-  VAULT_STATE_UNBOOTSTRAPPED = 1;
-  VAULT_STATE_SEALED = 2;
-  VAULT_STATE_UNSEALED = 3;
-  VAULT_STATE_ERROR = 4;
-}
-
-message UserAgentRequest {
-  oneof payload {
-    AuthChallengeRequest auth_challenge_request = 1;
-    AuthChallengeSolution auth_challenge_solution = 2;
-    UnsealStart unseal_start = 3;
-    UnsealEncryptedKey unseal_encrypted_key = 4;
-    google.protobuf.Empty query_vault_state = 5;
-    google.protobuf.Empty evm_wallet_create = 6;
-    google.protobuf.Empty evm_wallet_list = 7;
-    arbiter.evm.EvmGrantCreateRequest evm_grant_create = 8;
-    arbiter.evm.EvmGrantDeleteRequest evm_grant_delete = 9;
-    arbiter.evm.EvmGrantListRequest evm_grant_list = 10;
-  }
-}
-message UserAgentResponse {
-  oneof payload {
-    AuthChallenge auth_challenge = 1;
-    AuthOk auth_ok = 2;
-    UnsealStartResponse unseal_start_response = 3;
-    UnsealResult unseal_result = 4;
-    VaultState vault_state = 5;
-    arbiter.evm.WalletCreateResponse evm_wallet_create = 6;
-    arbiter.evm.WalletListResponse evm_wallet_list = 7;
-    arbiter.evm.EvmGrantCreateResponse evm_grant_create = 8;
-    arbiter.evm.EvmGrantDeleteResponse evm_grant_delete = 9;
-    arbiter.evm.EvmGrantListResponse evm_grant_list = 10;
-  }
-}

server/.cargo/audit.toml

@@ -0,0 +1,13 @@
+[advisories]
+# RUSTSEC-2023-0071: Marvin Attack timing side-channel in rsa crate.
+# No fixed version is available upstream.
+# RSA support is required for Windows Hello / KeyCredentialManager
+# (https://learn.microsoft.com/en-us/uwp/api/windows.security.credentials.keycredentialmanager.requestcreateasync),
+# which only issues RSA-2048 keys.
+# Mitigations in place:
+#   - Signing uses BlindedSigningKey (PSS+SHA-256), which applies blinding to
+#     protect the private key from timing recovery during signing.
+#   - RSA decryption is never performed; we only verify public-key signatures.
+#   - The attack requires local, high-resolution timing access against the
+#     signing process, which is not exposed in our threat model.
+ignore = ["RUSTSEC-2023-0071"]

server/.cargo/config.toml

@@ -0,0 +1,2 @@
+[env]
+MACOSX_DEPLOYMENT_TARGET = "26.3"

server/.cargo/mutants.toml

@@ -0,0 +1 @@
+test_tool = "nextest"

server/.gitignore

@@ -0,0 +1,2 @@
+mutants.out/
+mutants.out.old/

server/Cargo.toml

@@ -6,33 +6,166 @@ resolver = "3"
 
 
 [workspace.dependencies]
-tonic = { version = "0.14.3", features = [
-    "deflate",
-    "gzip",
-    "tls-connect-info",
-    "zstd",
-] }
-tracing = "0.1.44"
-tokio = { version = "1.49.0", features = ["full"] }
-ed25519-dalek = { version = "3.0.0-pre.6", features = ["rand_core"] }
-chrono = { version = "0.4.43", features = ["serde"] }
-rand = "0.10.0"
-rustls = "0.23.36"
-smlang = "0.8.0"
-miette = { version = "7.6.0", features = ["fancy", "serde"] }
-thiserror = "2.0.18"
+alloy = "2.0.4"
 async-trait = "0.1.89"
-futures = "0.3.31"
-tokio-stream = { version = "0.1.18", features = ["full"] }
-kameo = "0.19.2"
+base64 = "0.22.1"
+chrono = { version = "0.4.44", features = ["serde"] }
+futures = "0.3.32"
+k256 = { version = "0.13.4", features = ["ecdsa", "pkcs8"] }
+kameo = {git = "https://github.com/hdbg/kameo.git", rev = "17af90e3"}
+kameo_actors = {git = "https://github.com/hdbg/kameo.git", rev = "17af90e3"}
+hmac = "0.13.0"
+miette = { version = "7.6.0", features = ["fancy", "serde"] }
+ml-dsa = { version = "0.1.0-rc.9", features = ["zeroize"] }
+mutants = "0.0.4"
+prost = "0.14.3"
 prost-types = { version = "0.14.3", features = ["chrono"] }
-x25519-dalek = { version = "2.0.1", features = ["getrandom"] }
+rand = "0.10.1"
+rcgen = { version = "0.14.7", features = [ "aws_lc_rs",  "pem", "x509-parser", "zeroize" ], default-features = false }
 rstest = "0.26.1"
-rustls-pki-types = "1.14.0"
-alloy = "1.7.3"
-rcgen = { version = "0.14.7", features = [
-    "aws_lc_rs",
-    "pem",
-    "x509-parser",
-    "zeroize",
-], default-features = false }
+rustls = { version = "0.23.40", features = ["aws-lc-rs", "logging", "prefer-post-quantum", "std"], default-features = false }
+rustls-pki-types = "1.14.1"
+sha2 = "0.11"
+smlang = "0.8.0"
+strum = { version = "0.28.0", features = ["derive"] }
+thiserror = "2.0.18"
+tokio = { version = "1.52.1", features = ["full"] }
+tokio-stream = { version = "0.1.18", features = ["full"] }
+tonic = { version = "0.14.5", features = [ "deflate", "gzip", "tls-connect-info", "zstd" ] }
+tracing = "0.1.44"
+x25519-dalek = { version = "2.0.1", features = ["getrandom"] }
+
+[workspace.lints.rust]
+missing_unsafe_on_extern = "deny"
+unsafe_attr_outside_unsafe = "deny"
+unsafe_op_in_unsafe_fn = "deny"
+unstable_features = "deny"
+
+deprecated_safe_2024 = "warn"
+ffi_unwind_calls = "warn"
+linker_messages = "warn"
+
+elided_lifetimes_in_paths = "warn"
+explicit_outlives_requirements = "warn"
+impl-trait-overcaptures = "warn"
+impl-trait-redundant-captures = "warn"
+redundant_lifetimes = "warn"
+single_use_lifetimes = "warn"
+unused_lifetimes = "warn"
+
+macro_use_extern_crate = "warn"
+redundant_imports = "warn"
+unused_import_braces = "warn"
+unused_macro_rules = "warn"
+unused_qualifications = "warn"
+
+unit_bindings = "warn"
+
+# missing_docs = "warn" # ENABLE BY THE FIRST MAJOR VERSION!!
+unnameable_types = "warn"
+
+[workspace.lints.clippy]
+derive_partial_eq_without_eq = "allow" 
+future_not_send = "allow"
+inconsistent_struct_constructor = "allow"
+inline_always = "allow"
+missing_errors_doc = "allow"
+missing_fields_in_debug = "allow"
+missing_panics_doc = "allow"
+must_use_candidate = "allow"
+needless_pass_by_ref_mut = "allow"
+pub_underscore_fields = "allow"
+redundant_pub_crate = "allow" 
+uninhabited_references = "allow" # safe with unsafe_code = "forbid" and standard uninhabited pattern (match *self {})
+
+# restriction lints
+alloc_instead_of_core = "warn"
+allow_attributes_without_reason = "warn"
+as_conversions = "warn"
+assertions_on_result_states = "warn"
+cfg_not_test = "warn"
+clone_on_ref_ptr = "warn"
+cognitive_complexity = "warn"
+create_dir = "warn"
+dbg_macro = "warn"
+decimal_literal_representation = "warn"
+default_union_representation = "warn"
+deref_by_slicing = "warn"
+disallowed_script_idents = "warn"
+doc_include_without_cfg = "warn"
+empty_drop = "warn"
+empty_enum_variants_with_brackets = "warn"
+empty_structs_with_brackets = "warn"
+exit = "warn"
+filetype_is_file = "warn"
+float_arithmetic = "warn"
+float_cmp_const = "warn"
+fn_to_numeric_cast_any = "warn"
+get_unwrap = "warn"
+if_then_some_else_none = "warn"
+indexing_slicing = "warn"
+infinite_loop = "warn"
+inline_asm_x86_att_syntax = "warn"
+inline_asm_x86_intel_syntax = "warn"
+large_include_file = "warn"
+lossy_float_literal = "warn"
+map_with_unused_argument_over_ranges = "warn"
+mem_forget = "warn"
+missing_assert_message = "warn"
+mixed_read_write_in_expression = "warn"
+modulo_arithmetic = "warn"
+multiple_unsafe_ops_per_block = "warn"
+mutex_atomic = "warn"
+mutex_integer = "warn"
+needless_raw_strings = "warn"
+non_ascii_literal = "warn"
+non_zero_suggestions = "warn"
+pathbuf_init_then_push = "warn"
+pointer_format = "warn"
+precedence_bits = "warn"
+pub_without_shorthand = "warn"
+rc_buffer = "warn"
+rc_mutex = "warn"
+redundant_test_prefix = "warn"
+redundant_type_annotations = "warn"
+ref_patterns = "warn"
+renamed_function_params = "warn"
+rest_pat_in_fully_bound_structs = "warn"
+return_and_then = "warn"
+semicolon_inside_block = "warn"
+str_to_string = "warn"
+string_add = "warn"
+string_lit_chars_any = "warn"
+string_slice = "warn"
+suspicious_xor_used_as_pow = "warn"
+try_err = "warn"
+undocumented_unsafe_blocks = "warn"
+uninlined_format_args = "warn"
+unnecessary_safety_comment = "warn"
+unnecessary_safety_doc = "warn"
+unnecessary_self_imports = "warn"
+unneeded_field_pattern = "warn"
+unused_result_ok = "warn"
+verbose_file_reads = "warn"
+
+# cargo lints
+negative_feature_names = "warn"
+redundant_feature_names = "warn"
+wildcard_dependencies = "warn"
+
+# ENABLE BY THE FIRST MAJOR VERSION!!
+# todo = "warn"
+# unimplemented = "warn"
+# panic = "warn"
+# panic_in_result_fn = "warn"
+# 
+# cargo_common_metadata = "warn"
+# multiple_crate_versions = "warn" # a controversial option since it's really difficult to maintain
+
+disallowed_methods = "deny"
+
+nursery = { level = "warn", priority = -1 }
+pedantic = { level = "warn", priority = -1 }
+
+type_repetition_in_bounds = "allow"   # sometimes, it's better for readability this way
+unused_async_trait_impl = "allow"

server/clippy.toml

@@ -0,0 +1,30 @@
+disallowed-methods = [
+    # RSA decryption is forbidden: the rsa crate has RUSTSEC-2023-0071 (Marvin Attack).
+    # We only use RSA for Windows Hello (KeyCredentialManager) public-key verification — decryption
+    # is never required and must not be introduced.
+    { path = "rsa::RsaPrivateKey::decrypt", reason = "RSA decryption is forbidden (RUSTSEC-2023-0071 Marvin Attack). Only PSS signing/verification is permitted." },
+    { path = "rsa::RsaPrivateKey::decrypt_blinded", reason = "RSA decryption is forbidden (RUSTSEC-2023-0071 Marvin Attack). Only PSS signing/verification is permitted." },
+    { path = "rsa::traits::Decryptor::decrypt", reason = "RSA decryption is forbidden (RUSTSEC-2023-0071 Marvin Attack). This blocks decrypt() on rsa::{pkcs1v15,oaep}::DecryptingKey." },
+    { path = "rsa::traits::RandomizedDecryptor::decrypt_with_rng", reason = "RSA decryption is forbidden (RUSTSEC-2023-0071 Marvin Attack). This blocks decrypt_with_rng() on rsa::{pkcs1v15,oaep}::DecryptingKey." },
+]
+
+allow-indexing-slicing-in-tests = true
+allow-panic-in-tests = true
+check-inconsistent-struct-field-initializers = true
+suppress-restriction-lint-in-const = true
+allow-renamed-params-for = [
+    "core::convert::From",
+    "core::convert::TryFrom",
+    "core::str::FromStr",
+    "kameo::actor::Actor",
+]
+
+module-items-ordered-within-groupings = ["UPPER_SNAKE_CASE"]
+source-item-ordering = ["enum"]
+trait-assoc-item-kinds-order = [
+    "const",
+    "type",
+    "fn",
+] # community tested standard
+
+too-many-lines-threshold = 150

server/crates/arbiter-client/Cargo.toml

@@ -5,4 +5,25 @@ edition = "2024"
 repository = "https://git.markettakers.org/MarketTakers/arbiter"
 license = "Apache-2.0"
 
+[lints]
+workspace = true
+
+[features]
+evm = ["dep:alloy"]
+
 [dependencies]
+arbiter-proto.path = "../arbiter-proto"
+arbiter-crypto.path = "../arbiter-crypto"
+alloy = { workspace = true, optional = true }
+tonic.workspace = true
+tonic.features = ["tls-aws-lc"]
+tokio.workspace = true
+tokio-stream.workspace = true
+thiserror.workspace = true
+http = "1.4.0"
+rustls-webpki = { version = "0.103.13", features = ["aws-lc-rs"] }
+async-trait.workspace = true
+chrono.workspace = true
+
+[lib]
+doctest = false

server/crates/arbiter-client/src/auth.rs

@@ -0,0 +1,160 @@
+use crate::{
+    storage::StorageError,
+    transport::{ClientTransport, next_request_id},
+};
+use arbiter_crypto::authn::{self, SigningContext, SigningKey};
+use arbiter_proto::{
+    ClientMetadata,
+    proto::{
+        client::{
+            ClientRequest,
+            auth::{
+                self as proto_auth, AuthChallenge, AuthChallengeRequest, AuthChallengeSolution,
+                AuthResult, request::Payload as AuthRequestPayload,
+                response::Payload as AuthResponsePayload,
+            },
+            client_request::Payload as ClientRequestPayload,
+            client_response::Payload as ClientResponsePayload,
+        },
+        shared::ClientInfo as ProtoClientInfo,
+    },
+};
+
+use chrono::DateTime;
+
+#[derive(Debug, thiserror::Error)]
+pub enum AuthError {
+    #[error("Server sent invalid auth challenge")]
+    InvalidChallenge,
+    #[error("Client approval denied by Operator")]
+    ApprovalDenied,
+    #[error("Auth challenge was not returned by server")]
+    MissingAuthChallenge,
+
+    #[error("No Operators online to approve client")]
+    NoOperatorsOnline,
+
+    #[error("Signing key storage error")]
+    Storage(#[from] StorageError),
+
+    #[error("Unexpected auth response payload")]
+    UnexpectedAuthResponse,
+}
+
+fn map_auth_result(code: i32) -> AuthError {
+    match AuthResult::try_from(code).unwrap_or(AuthResult::Unspecified) {
+        AuthResult::ApprovalDenied => AuthError::ApprovalDenied,
+        AuthResult::NoOperatorsOnline => AuthError::NoOperatorsOnline,
+        AuthResult::Unspecified
+        | AuthResult::Success
+        | AuthResult::InvalidKey
+        | AuthResult::InvalidSignature
+        | AuthResult::Internal => AuthError::UnexpectedAuthResponse,
+    }
+}
+
+async fn send_auth_challenge_request(
+    transport: &mut ClientTransport,
+    metadata: ClientMetadata,
+    key: &SigningKey,
+) -> Result<(), AuthError> {
+    transport
+        .send(ClientRequest {
+            request_id: next_request_id(),
+            payload: Some(ClientRequestPayload::Auth(proto_auth::Request {
+                payload: Some(AuthRequestPayload::ChallengeRequest(AuthChallengeRequest {
+                    pubkey: key.public_key().to_bytes(),
+                    client_info: Some(ProtoClientInfo {
+                        name: metadata.name,
+                        description: metadata.description,
+                        version: metadata.version,
+                    }),
+                })),
+            })),
+        })
+        .await
+        .map_err(|_| AuthError::UnexpectedAuthResponse)
+}
+
+async fn receive_auth_challenge(
+    transport: &mut ClientTransport,
+) -> Result<AuthChallenge, AuthError> {
+    let response = transport
+        .recv()
+        .await
+        .map_err(|_| AuthError::MissingAuthChallenge)?;
+
+    let payload = response.payload.ok_or(AuthError::MissingAuthChallenge)?;
+    match payload {
+        ClientResponsePayload::Auth(response) => match response.payload {
+            Some(AuthResponsePayload::Challenge(challenge)) => Ok(challenge),
+            Some(AuthResponsePayload::Result(result)) => Err(map_auth_result(result)),
+            None => Err(AuthError::MissingAuthChallenge),
+        },
+        _ => Err(AuthError::UnexpectedAuthResponse),
+    }
+}
+
+async fn send_auth_challenge_solution(
+    transport: &mut ClientTransport,
+    key: &SigningKey,
+    challenge: AuthChallenge,
+) -> Result<(), AuthError> {
+    let timestamp = DateTime::from_timestamp_nanos(challenge.timestamp_nanos as i64);
+    let challenge = authn::AuthChallenge {
+        nonce: *challenge
+            .random
+            .as_array()
+            .ok_or(AuthError::InvalidChallenge)?,
+        timestamp,
+    };
+    let challenge_payload: Vec<u8> = challenge.format();
+    let signature = key
+        .sign_message(&challenge_payload, SigningContext::Client)
+        .map_err(|_| AuthError::UnexpectedAuthResponse)?
+        .to_bytes();
+
+    transport
+        .send(ClientRequest {
+            request_id: next_request_id(),
+            payload: Some(ClientRequestPayload::Auth(proto_auth::Request {
+                payload: Some(AuthRequestPayload::ChallengeSolution(
+                    AuthChallengeSolution { signature },
+                )),
+            })),
+        })
+        .await
+        .map_err(|_| AuthError::UnexpectedAuthResponse)
+}
+
+async fn receive_auth_confirmation(transport: &mut ClientTransport) -> Result<(), AuthError> {
+    let response = transport
+        .recv()
+        .await
+        .map_err(|_| AuthError::UnexpectedAuthResponse)?;
+
+    let payload = response.payload.ok_or(AuthError::UnexpectedAuthResponse)?;
+    match payload {
+        ClientResponsePayload::Auth(response) => match response.payload {
+            Some(AuthResponsePayload::Result(result))
+                if AuthResult::try_from(result).ok() == Some(AuthResult::Success) =>
+            {
+                Ok(())
+            }
+            Some(AuthResponsePayload::Result(result)) => Err(map_auth_result(result)),
+            _ => Err(AuthError::UnexpectedAuthResponse),
+        },
+        _ => Err(AuthError::UnexpectedAuthResponse),
+    }
+}
+
+pub async fn authenticate(
+    transport: &mut ClientTransport,
+    metadata: ClientMetadata,
+    key: &SigningKey,
+) -> Result<(), AuthError> {
+    send_auth_challenge_request(transport, metadata, key).await?;
+    let challenge = receive_auth_challenge(transport).await?;
+    send_auth_challenge_solution(transport, key, challenge).await?;
+    receive_auth_confirmation(transport).await
+}

server/crates/arbiter-client/src/bin/test_connect.rs

@@ -0,0 +1,44 @@
+use arbiter_client::ArbiterClient;
+use arbiter_proto::{ClientMetadata, url::ArbiterUrl};
+
+use std::io::{self, Write};
+
+#[tokio::main]
+async fn main() {
+    println!("Testing connection to Arbiter server...");
+    print!("Enter ArbiterUrl: ");
+    let _ = io::stdout().flush();
+
+    let mut input = String::new();
+    if let Err(err) = io::stdin().read_line(&mut input) {
+        eprintln!("Failed to read input: {err}");
+        return;
+    }
+
+    let input = input.trim();
+    if input.is_empty() {
+        eprintln!("ArbiterUrl cannot be empty");
+        return;
+    }
+
+    let url = match ArbiterUrl::try_from(input) {
+        Ok(url) => url,
+        Err(err) => {
+            eprintln!("Invalid ArbiterUrl: {err}");
+            return;
+        }
+    };
+
+    println!("{url:#?}");
+
+    let metadata = ClientMetadata {
+        name: "arbiter-client test_connect".to_owned(),
+        description: Some("Manual connection smoke test".to_owned()),
+        version: Some(env!("CARGO_PKG_VERSION").to_owned()),
+    };
+
+    match ArbiterClient::connect(url, metadata).await {
+        Ok(_) => println!("Connected and authenticated successfully."),
+        Err(err) => eprintln!("Failed to connect: {err:#?}"),
+    }
+}

server/crates/arbiter-client/src/client.rs

@@ -0,0 +1,101 @@
+#[cfg(feature = "evm")]
+use crate::wallets::evm::ArbiterEvmWallet;
+use crate::{
+    StorageError,
+    auth::{AuthError, authenticate},
+    storage::{FileSigningKeyStorage, SigningKeyStorage},
+    transport::{BUFFER_LENGTH, ClientTransport},
+};
+use arbiter_crypto::authn::SigningKey;
+use arbiter_proto::{
+    ClientMetadata, proto::arbiter_service_client::ArbiterServiceClient, url::ArbiterUrl,
+};
+
+use std::sync::Arc;
+use tokio::sync::{Mutex, mpsc};
+use tokio_stream::wrappers::ReceiverStream;
+use tonic::transport::ClientTlsConfig;
+
+#[derive(Debug, thiserror::Error)]
+pub enum ArbiterClientError {
+    #[error("Authentication error")]
+    Authentication(#[from] AuthError),
+
+    #[error("Could not establish connection")]
+    Connection(#[from] tonic::transport::Error),
+
+    #[error("gRPC error")]
+    Grpc(#[from] tonic::Status),
+
+    #[error("Invalid CA certificate")]
+    InvalidCaCert(#[from] webpki::Error),
+
+    #[error("Invalid server URI")]
+    InvalidUri(#[from] http::uri::InvalidUri),
+
+    #[error("Storage error")]
+    Storage(#[from] StorageError),
+}
+
+pub struct ArbiterClient {
+    #[expect(
+        dead_code,
+        reason = "transport will be used in future methods for sending requests and receiving responses"
+    )]
+    transport: Arc<Mutex<ClientTransport>>,
+}
+
+impl ArbiterClient {
+    pub async fn connect(
+        url: ArbiterUrl,
+        metadata: ClientMetadata,
+    ) -> Result<Self, ArbiterClientError> {
+        let storage = FileSigningKeyStorage::from_default_location()?;
+        Self::connect_with_storage(url, metadata, &storage).await
+    }
+
+    pub async fn connect_with_storage<S: SigningKeyStorage>(
+        url: ArbiterUrl,
+        metadata: ClientMetadata,
+        storage: &S,
+    ) -> Result<Self, ArbiterClientError> {
+        let key = storage.load_or_create()?;
+        Self::connect_with_key(url, metadata, key).await
+    }
+
+    pub async fn connect_with_key(
+        url: ArbiterUrl,
+        metadata: ClientMetadata,
+        key: SigningKey,
+    ) -> Result<Self, ArbiterClientError> {
+        let anchor = webpki::anchor_from_trusted_cert(&url.ca_cert)?.to_owned();
+        let tls = ClientTlsConfig::new().trust_anchor(anchor);
+
+        let channel =
+            tonic::transport::Channel::from_shared(format!("https://{}:{}", url.host, url.port))?
+                .tls_config(tls)?
+                .connect()
+                .await?;
+
+        let mut client = ArbiterServiceClient::new(channel);
+        let (tx, rx) = mpsc::channel(BUFFER_LENGTH);
+        let response_stream = client.client(ReceiverStream::new(rx)).await?.into_inner();
+
+        let mut transport = ClientTransport {
+            sender: tx,
+            receiver: response_stream,
+        };
+
+        authenticate(&mut transport, metadata, &key).await?;
+
+        Ok(Self {
+            transport: Arc::new(Mutex::new(transport)),
+        })
+    }
+
+    #[cfg(feature = "evm")]
+    #[expect(clippy::unused_async, reason = "false positive")]
+    pub async fn evm_wallets(&self) -> Result<Vec<ArbiterEvmWallet>, ArbiterClientError> {
+        todo!("fetch EVM wallet list from server")
+    }
+}

server/crates/arbiter-client/src/lib.rs

@@ -1,14 +1,12 @@
-pub fn add(left: u64, right: u64) -> u64 {
-    left + right
-}
+mod auth;
+mod client;
+mod storage;
+mod transport;
+pub mod wallets;
 
-#[cfg(test)]
-mod tests {
-    use super::*;
+pub use auth::AuthError;
+pub use client::{ArbiterClient, ArbiterClientError};
+pub use storage::{FileSigningKeyStorage, SigningKeyStorage, StorageError};
 
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
-    }
-}
+#[cfg(feature = "evm")]
+pub use wallets::evm::{ArbiterEvmSignTransactionError, ArbiterEvmWallet};

server/crates/arbiter-client/src/storage.rs

@@ -0,0 +1,134 @@
+use arbiter_crypto::authn::SigningKey;
+use arbiter_proto::home_path;
+
+use std::path::{Path, PathBuf};
+
+#[derive(Debug, thiserror::Error)]
+pub enum StorageError {
+    #[error("Invalid signing key length in storage: expected {expected} bytes, got {actual} bytes")]
+    InvalidKeyLength { expected: usize, actual: usize },
+
+    #[error("I/O error")]
+    Io(#[from] std::io::Error),
+}
+
+pub trait SigningKeyStorage {
+    fn load_or_create(&self) -> Result<SigningKey, StorageError>;
+}
+
+#[derive(Debug, Clone)]
+pub struct FileSigningKeyStorage {
+    path: PathBuf,
+}
+
+impl FileSigningKeyStorage {
+    pub const DEFAULT_FILE_NAME: &str = "sdk_client_ml_dsa.key";
+
+    pub fn new(path: impl Into<PathBuf>) -> Self {
+        Self { path: path.into() }
+    }
+
+    pub fn from_default_location() -> Result<Self, StorageError> {
+        Ok(Self::new(home_path()?.join(Self::DEFAULT_FILE_NAME)))
+    }
+
+    fn read_key(path: &Path) -> Result<SigningKey, StorageError> {
+        let bytes = std::fs::read(path)?;
+        let raw: [u8; 32] =
+            bytes
+                .try_into()
+                .map_err(|v: Vec<u8>| StorageError::InvalidKeyLength {
+                    expected: 32,
+                    actual: v.len(),
+                })?;
+        Ok(SigningKey::from_seed(raw))
+    }
+}
+
+impl SigningKeyStorage for FileSigningKeyStorage {
+    fn load_or_create(&self) -> Result<SigningKey, StorageError> {
+        if let Some(parent) = self.path.parent() {
+            std::fs::create_dir_all(parent)?;
+        }
+
+        if self.path.exists() {
+            return Self::read_key(&self.path);
+        }
+
+        let key = SigningKey::generate();
+        let raw_key = key.to_seed();
+
+        // Use create_new to prevent accidental overwrite if another process creates the key first.
+        match std::fs::OpenOptions::new()
+            .create_new(true)
+            .write(true)
+            .open(&self.path)
+        {
+            Ok(mut file) => {
+                use std::io::Write as _;
+                file.write_all(&raw_key)?;
+                Ok(key)
+            }
+            Err(err) if err.kind() == std::io::ErrorKind::AlreadyExists => {
+                Self::read_key(&self.path)
+            }
+            Err(err) => Err(StorageError::Io(err)),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{FileSigningKeyStorage, SigningKeyStorage, StorageError};
+
+    fn unique_temp_key_path() -> std::path::PathBuf {
+        let nanos = std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .expect("clock should be after unix epoch")
+            .as_nanos();
+        std::env::temp_dir().join(format!(
+            "arbiter-client-key-{}-{}.bin",
+            std::process::id(),
+            nanos
+        ))
+    }
+
+    #[test]
+    fn file_storage_creates_and_reuses_key() {
+        let path = unique_temp_key_path();
+        let storage = FileSigningKeyStorage::new(path.clone());
+
+        let key_a = storage
+            .load_or_create()
+            .expect("first load_or_create should create key");
+        let key_b = storage
+            .load_or_create()
+            .expect("second load_or_create should read same key");
+
+        assert_eq!(key_a.to_seed(), key_b.to_seed());
+        assert!(path.exists());
+
+        std::fs::remove_file(path).expect("temp key file should be removable");
+    }
+
+    #[test]
+    fn file_storage_rejects_invalid_key_length() {
+        let path = unique_temp_key_path();
+        std::fs::write(&path, [42u8; 31]).expect("should write invalid key file");
+        let storage = FileSigningKeyStorage::new(path.clone());
+
+        let err = storage
+            .load_or_create()
+            .expect_err("storage should reject non-32-byte key file");
+
+        match err {
+            StorageError::InvalidKeyLength { expected, actual } => {
+                assert_eq!(expected, 32);
+                assert_eq!(actual, 31);
+            }
+            other @ StorageError::Io(_) => panic!("unexpected error: {other:?}"),
+        }
+
+        std::fs::remove_file(path).expect("temp key file should be removable");
+    }
+}

server/crates/arbiter-client/src/transport.rs

@@ -0,0 +1,41 @@
+use arbiter_proto::proto::client::{ClientRequest, ClientResponse};
+
+use std::sync::atomic::{AtomicI32, Ordering};
+use tokio::sync::mpsc;
+
+pub const BUFFER_LENGTH: usize = 16;
+static NEXT_REQUEST_ID: AtomicI32 = AtomicI32::new(1);
+
+pub fn next_request_id() -> i32 {
+    NEXT_REQUEST_ID.fetch_add(1, Ordering::Relaxed)
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum ClientSignError {
+    #[error("Transport channel closed")]
+    ChannelClosed,
+
+    #[error("Connection closed by server")]
+    ConnectionClosed,
+}
+
+pub struct ClientTransport {
+    pub(crate) sender: mpsc::Sender<ClientRequest>,
+    pub(crate) receiver: tonic::Streaming<ClientResponse>,
+}
+
+impl ClientTransport {
+    pub(crate) async fn send(&mut self, request: ClientRequest) -> Result<(), ClientSignError> {
+        self.sender
+            .send(request)
+            .await
+            .map_err(|_| ClientSignError::ChannelClosed)
+    }
+
+    pub(crate) async fn recv(&mut self) -> Result<ClientResponse, ClientSignError> {
+        match self.receiver.message().await {
+            Ok(Some(resp)) => Ok(resp),
+            Ok(None) | Err(_) => Err(ClientSignError::ConnectionClosed),
+        }
+    }
+}

server/crates/arbiter-client/src/wallets/evm.rs

@@ -0,0 +1,197 @@
+use crate::transport::{ClientTransport, next_request_id};
+use arbiter_proto::proto::{
+    client::{
+        ClientRequest,
+        client_request::Payload as ClientRequestPayload,
+        client_response::Payload as ClientResponsePayload,
+        evm::{
+            self as proto_evm, request::Payload as EvmRequestPayload,
+            response::Payload as EvmResponsePayload,
+        },
+    },
+    evm::{
+        EvmSignTransactionRequest,
+        evm_sign_transaction_response::Result as EvmSignTransactionResult,
+    },
+    shared::evm::TransactionEvalError,
+};
+
+use alloy::{
+    consensus::SignableTransaction,
+    network::TxSigner,
+    primitives::{Address, B256, ChainId, Signature},
+    signers::{Error, Result, Signer},
+};
+use async_trait::async_trait;
+use std::sync::Arc;
+use tokio::sync::Mutex;
+
+/// A typed error payload returned by [`ArbiterEvmWallet`] transaction signing.
+///
+/// This is wrapped into `alloy::signers::Error::Other`, so consumers can downcast by [`TryFrom`] and
+/// interpret the concrete policy evaluation failure instead of parsing strings.
+#[derive(Debug, thiserror::Error)]
+#[non_exhaustive]
+pub enum ArbiterEvmSignTransactionError {
+    #[error("transaction rejected by policy: {0:?}")]
+    PolicyEval(TransactionEvalError),
+}
+
+impl<'a> TryFrom<&'a Error> for &'a ArbiterEvmSignTransactionError {
+    type Error = ();
+
+    fn try_from(value: &'a Error) -> Result<Self, Self::Error> {
+        if let Error::Other(inner) = value
+            && let Some(eval_error) = inner.downcast_ref()
+        {
+            Ok(eval_error)
+        } else {
+            Err(())
+        }
+    }
+}
+
+pub struct ArbiterEvmWallet {
+    transport: Arc<Mutex<ClientTransport>>,
+    address: Address,
+    chain_id: Option<ChainId>,
+}
+
+impl ArbiterEvmWallet {
+    #[expect(
+        dead_code,
+        reason = "new will be used in future methods for creating wallets with different parameters"
+    )]
+    pub(crate) const fn new(transport: Arc<Mutex<ClientTransport>>, address: Address) -> Self {
+        Self {
+            transport,
+            address,
+            chain_id: None,
+        }
+    }
+
+    pub const fn address(&self) -> Address {
+        self.address
+    }
+
+    #[must_use]
+    pub const fn with_chain_id(mut self, chain_id: ChainId) -> Self {
+        self.chain_id = Some(chain_id);
+        self
+    }
+
+    fn validate_chain_id(&self, tx: &mut dyn SignableTransaction<Signature>) -> Result<()> {
+        if let Some(chain_id) = self.chain_id
+            && !tx.set_chain_id_checked(chain_id)
+        {
+            return Err(Error::TransactionChainIdMismatch {
+                signer: chain_id,
+                tx: tx.chain_id().unwrap(),
+            });
+        }
+
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl Signer for ArbiterEvmWallet {
+    async fn sign_hash(&self, _hash: &B256) -> Result<Signature> {
+        Err(Error::other(
+            "hash-only signing is not supported for ArbiterEvmWallet; use transaction signing",
+        ))
+    }
+
+    fn address(&self) -> Address {
+        self.address
+    }
+
+    fn chain_id(&self) -> Option<ChainId> {
+        self.chain_id
+    }
+
+    fn set_chain_id(&mut self, chain_id: Option<ChainId>) {
+        self.chain_id = chain_id;
+    }
+}
+
+#[async_trait]
+impl TxSigner<Signature> for ArbiterEvmWallet {
+    fn address(&self) -> Address {
+        self.address
+    }
+
+    async fn sign_transaction(
+        &self,
+        tx: &mut dyn SignableTransaction<Signature>,
+    ) -> Result<Signature> {
+        self.validate_chain_id(tx)?;
+
+        let mut transport = self.transport.lock().await;
+        let request_id = next_request_id();
+        let rlp_transaction = tx.encoded_for_signing();
+
+        transport
+            .send(ClientRequest {
+                request_id,
+                payload: Some(ClientRequestPayload::Evm(proto_evm::Request {
+                    payload: Some(EvmRequestPayload::SignTransaction(
+                        EvmSignTransactionRequest {
+                            wallet_address: self.address.to_vec(),
+                            rlp_transaction,
+                        },
+                    )),
+                })),
+            })
+            .await
+            .map_err(|_| Error::other("failed to send evm sign transaction request"))?;
+
+        let response = transport
+            .recv()
+            .await
+            .map_err(|_| Error::other("failed to receive evm sign transaction response"))?;
+        drop(transport);
+
+        if response.request_id != Some(request_id) {
+            return Err(Error::other(
+                "received mismatched response id for evm sign transaction",
+            ));
+        }
+
+        let payload = response
+            .payload
+            .ok_or_else(|| Error::other("missing evm sign transaction response payload"))?;
+
+        let ClientResponsePayload::Evm(proto_evm::Response {
+            payload: Some(payload),
+        }) = payload
+        else {
+            return Err(Error::other(
+                "unexpected response payload for evm sign transaction request",
+            ));
+        };
+
+        let EvmResponsePayload::SignTransaction(response) = payload else {
+            return Err(Error::other(
+                "unexpected evm response payload for sign transaction request",
+            ));
+        };
+
+        let result = response
+            .result
+            .ok_or_else(|| Error::other("missing evm sign transaction result"))?;
+
+        match result {
+            EvmSignTransactionResult::Signature(signature) => {
+                Signature::try_from(signature.as_slice())
+                    .map_err(|_| Error::other("invalid signature returned by server"))
+            }
+            EvmSignTransactionResult::EvalError(eval_error) => Err(Error::other(
+                ArbiterEvmSignTransactionError::PolicyEval(eval_error),
+            )),
+            EvmSignTransactionResult::Error(code) => Err(Error::other(format!(
+                "server failed to sign transaction with error code {code}"
+            ))),
+        }
+    }
+}

server/crates/arbiter-client/src/wallets/mod.rs

@@ -0,0 +1,2 @@
+#[cfg(feature = "evm")]
+pub mod evm;

server/crates/arbiter-crypto/.gitignore

@@ -0,0 +1 @@
+/target

server/crates/arbiter-crypto/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "arbiter-crypto"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+ml-dsa = {workspace = true, optional = true }
+rand = {workspace = true, optional = true}
+memsafe = {version = "0.4.0", optional = true}
+strum = { workspace = true, optional = true }
+hmac.workspace = true
+alloy.workspace = true
+x-wing = { version = "0.1.0-rc.0", features = ["zeroize"] }
+chrono.workspace = true
+thiserror.workspace = true
+
+[lints]
+workspace = true
+
+[features]
+default = ["authn", "safecell"]
+authn = ["dep:ml-dsa", "dep:rand", "dep:strum"]
+safecell = ["dep:memsafe"]
+
+[lib]
+doctest = false

server/crates/arbiter-crypto/src/authn/mod.rs

@@ -0,0 +1,2 @@
+pub mod v1;
+pub use v1::*;

server/crates/arbiter-crypto/src/authn/v1.rs

@@ -0,0 +1,288 @@
+use chrono::{DateTime, Utc};
+use hmac::digest::Digest;
+use ml_dsa::{
+    EncodedVerifyingKey, Error, KeyGen, MlDsa87, Seed, Signature as MlDsaSignature,
+    SigningKey as MlDsaSigningKey, VerifyingKey as MlDsaVerifyingKey, signature::Keypair as _,
+};
+use rand::RngExt;
+use strum::IntoStaticStr;
+
+/// Domain separation tag mixed into every ML-DSA signature.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, IntoStaticStr)]
+pub enum SigningContext {
+    #[strum(serialize = "arbiter_client")]
+    Client,
+    #[strum(serialize = "arbiter_operator")]
+    Operator,
+    #[strum(serialize = "arbiter_governance_vote")]
+    GovernanceVote,
+}
+
+impl SigningContext {
+    #[must_use]
+    pub fn as_bytes(self) -> &'static [u8] {
+        <&'static str>::from(self).as_bytes()
+    }
+}
+
+const NONCE_SIZE: usize = 32;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, thiserror::Error)]
+#[error("invalid length: expected {expected} bytes, got {actual} bytes")]
+pub struct InvalidLength {
+    pub expected: usize,
+    pub actual: usize,
+}
+
+#[derive(Debug, Clone)]
+pub struct AuthChallenge {
+    pub nonce: [u8; NONCE_SIZE],
+    pub timestamp: DateTime<Utc>,
+}
+
+impl AuthChallenge {
+    pub fn generate(rng: &mut impl rand::CryptoRng) -> Self {
+        let timestamp = Utc::now();
+        let nonce = {
+            let mut array = [0; NONCE_SIZE];
+            rng.fill(&mut array);
+            array
+        };
+
+        Self { nonce, timestamp }
+    }
+
+    pub fn format(&self) -> Vec<u8> {
+        {
+            let mut buffer = Vec::from(self.nonce);
+
+            let stamp = self
+                .timestamp
+                .timestamp_nanos_opt()
+                .expect("We would be long dead by the time this triggers :)");
+            buffer.extend_from_slice(stamp.to_be_bytes().as_slice());
+
+            buffer
+        }
+    }
+
+    pub fn from_parts(nonce: &[u8], timestamp: i64) -> Result<Self, InvalidLength> {
+        let random_nonce = nonce.as_array().ok_or(InvalidLength {
+            expected: NONCE_SIZE,
+            actual: nonce.len(),
+        })?;
+        Ok(Self {
+            nonce: *random_nonce,
+            timestamp: DateTime::from_timestamp_nanos(timestamp),
+        })
+    }
+}
+
+pub type KeyParams = MlDsa87;
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct PublicKey(Box<MlDsaVerifyingKey<KeyParams>>);
+
+impl crate::hashing::Hashable for PublicKey {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        hasher.update(self.to_bytes());
+    }
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct Signature(Box<MlDsaSignature<KeyParams>>);
+
+#[derive(Debug)]
+pub struct SigningKey(Box<MlDsaSigningKey<KeyParams>>);
+
+impl PublicKey {
+    pub fn to_bytes(&self) -> Vec<u8> {
+        self.0.encode().0.to_vec()
+    }
+
+    #[must_use]
+    pub fn verify(
+        &self,
+        challenge: &AuthChallenge,
+        context: SigningContext,
+        signature: &Signature,
+    ) -> bool {
+        let challenge = challenge.format();
+        self.0
+            .verify_with_context(&challenge, context.as_bytes(), &signature.0)
+    }
+
+    #[must_use]
+    pub fn verify_message(
+        &self,
+        message: &[u8],
+        context: SigningContext,
+        signature: &Signature,
+    ) -> bool {
+        self.0
+            .verify_with_context(message, context.as_bytes(), &signature.0)
+    }
+}
+
+impl Signature {
+    pub fn to_bytes(&self) -> Vec<u8> {
+        self.0.encode().0.to_vec()
+    }
+}
+
+impl SigningKey {
+    pub fn generate() -> Self {
+        Self(Box::new(KeyParams::key_gen(&mut rand::rng())))
+    }
+
+    pub fn from_seed(seed: [u8; 32]) -> Self {
+        Self(Box::new(KeyParams::from_seed(&Seed::from(seed))))
+    }
+
+    pub fn to_seed(&self) -> [u8; 32] {
+        self.0.to_seed().into()
+    }
+
+    pub fn public_key(&self) -> PublicKey {
+        self.0.verifying_key().into()
+    }
+
+    pub fn sign_message(
+        &self,
+        message: &[u8],
+        context: SigningContext,
+    ) -> Result<Signature, Error> {
+        self.0
+            .signing_key()
+            .sign_deterministic(message, context.as_bytes())
+            .map(Into::into)
+    }
+
+    pub fn sign_challenge(
+        &self,
+        challenge: &AuthChallenge,
+        context: SigningContext,
+    ) -> Result<Signature, Error> {
+        let challenge = challenge.format();
+
+        self.sign_message(&challenge, context)
+    }
+}
+
+impl From<MlDsaVerifyingKey<KeyParams>> for PublicKey {
+    fn from(value: MlDsaVerifyingKey<KeyParams>) -> Self {
+        Self(Box::new(value))
+    }
+}
+
+impl From<MlDsaSignature<KeyParams>> for Signature {
+    fn from(value: MlDsaSignature<KeyParams>) -> Self {
+        Self(Box::new(value))
+    }
+}
+
+impl From<MlDsaSigningKey<KeyParams>> for SigningKey {
+    fn from(value: MlDsaSigningKey<KeyParams>) -> Self {
+        Self(Box::new(value))
+    }
+}
+
+impl TryFrom<Vec<u8>> for PublicKey {
+    type Error = ();
+
+    fn try_from(value: Vec<u8>) -> Result<Self, Self::Error> {
+        Self::try_from(value.as_slice())
+    }
+}
+
+impl TryFrom<&'_ [u8]> for PublicKey {
+    type Error = ();
+
+    fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
+        let encoded = EncodedVerifyingKey::<KeyParams>::try_from(value).map_err(|_| ())?;
+        Ok(Self(Box::new(MlDsaVerifyingKey::decode(&encoded))))
+    }
+}
+
+impl TryFrom<Vec<u8>> for Signature {
+    type Error = ();
+
+    fn try_from(value: Vec<u8>) -> Result<Self, Self::Error> {
+        Self::try_from(value.as_slice())
+    }
+}
+
+impl TryFrom<&'_ [u8]> for Signature {
+    type Error = ();
+
+    fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
+        MlDsaSignature::try_from(value)
+            .map(|sig| Self(Box::new(sig)))
+            .map_err(|_| ())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use ml_dsa::{KeyGen, MlDsa87, signature::Keypair as _};
+
+    use crate::authn::AuthChallenge;
+
+    use super::{PublicKey, Signature, SigningContext, SigningKey};
+
+    #[test]
+    fn public_key_round_trip_decodes() {
+        let key = MlDsa87::key_gen(&mut rand::rng());
+        let encoded = PublicKey::from(key.verifying_key()).to_bytes();
+
+        let decoded = PublicKey::try_from(encoded.as_slice()).expect("public key should decode");
+
+        assert_eq!(decoded, PublicKey::from(key.verifying_key()));
+    }
+
+    #[test]
+    fn signature_round_trip_decodes() {
+        let key = SigningKey::generate();
+        let signature = key
+            .sign_message(b"challenge", SigningContext::Client)
+            .expect("signature should be created");
+
+        let decoded =
+            Signature::try_from(signature.to_bytes().as_slice()).expect("signature should decode");
+
+        assert_eq!(decoded, signature);
+    }
+
+    #[test]
+    fn challenge_verification_uses_context_and_canonical_key_bytes() {
+        let key = SigningKey::generate();
+        let public_key = key.public_key();
+        let challenge = AuthChallenge::generate(&mut rand::rng());
+        let signature = key
+            .sign_challenge(&challenge, SigningContext::Client)
+            .expect("signature should be created");
+
+        assert!(public_key.verify(&challenge, SigningContext::Client, &signature));
+        assert!(!public_key.verify(&challenge, SigningContext::Operator, &signature));
+    }
+
+    #[test]
+    fn signing_key_round_trip_seed_preserves_public_key_and_signing() {
+        let original = SigningKey::generate();
+        let restored = SigningKey::from_seed(original.to_seed());
+
+        assert_eq!(restored.public_key(), original.public_key());
+
+        let challenge = AuthChallenge::generate(&mut rand::rng());
+
+        let signature = restored
+            .sign_challenge(&challenge, SigningContext::Client)
+            .expect("signature should be created");
+
+        assert!(
+            restored
+                .public_key()
+                .verify(&challenge, SigningContext::Client, &signature)
+        );
+    }
+}

server/crates/arbiter-crypto/src/hashing.rs

@@ -0,0 +1,112 @@
+use std::collections::HashSet;
+
+pub use hmac::digest::Digest;
+
+/// Deterministically hash a value by feeding its fields into the hasher in a consistent order.
+#[diagnostic::on_unimplemented(
+    note = "for local types consider adding `#[derive(arbiter_macros::Hashable)]` to your `{Self}` type",
+    note = "for types from other crates check whether the crate offers a `Hashable` implementation"
+)]
+pub trait Hashable {
+    fn hash<H: Digest>(&self, hasher: &mut H);
+}
+
+macro_rules! impl_numeric {
+    ($($t:ty),*) => {
+        $(
+            impl Hashable for $t {
+                fn hash<H: Digest>(&self, hasher: &mut H) {
+                    hasher.update(&self.to_be_bytes());
+                }
+            }
+        )*
+    };
+}
+
+impl_numeric!(u8, u16, u32, u64, i8, i16, i32, i64);
+
+impl Hashable for &[u8] {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        hasher.update(self);
+    }
+}
+
+impl Hashable for String {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        hasher.update(self.as_bytes());
+    }
+}
+
+impl<T: Hashable + PartialOrd> Hashable for Vec<T> {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        let ref_sorted = {
+            let mut sorted = self.iter().collect::<Vec<_>>();
+            sorted.sort_by(|a, b| a.partial_cmp(b).unwrap());
+            sorted
+        };
+        for item in ref_sorted {
+            item.hash(hasher);
+        }
+    }
+}
+
+impl<T: Hashable + PartialOrd, S: std::hash::BuildHasher> Hashable for HashSet<T, S> {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        let ref_sorted = {
+            let mut sorted = self.iter().collect::<Vec<_>>();
+            sorted.sort_by(|a, b| a.partial_cmp(b).unwrap());
+            sorted
+        };
+        for item in ref_sorted {
+            item.hash(hasher);
+        }
+    }
+}
+
+impl<T: Hashable> Hashable for Option<T> {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        match self {
+            Some(value) => {
+                hasher.update([1]);
+                value.hash(hasher);
+            }
+            None => hasher.update([0]),
+        }
+    }
+}
+
+impl<T: Hashable> Hashable for Box<T> {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        self.as_ref().hash(hasher);
+    }
+}
+
+impl<T: Hashable> Hashable for &T {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        (*self).hash(hasher);
+    }
+}
+
+impl Hashable for alloy::primitives::Address {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        hasher.update(self.as_slice());
+    }
+}
+
+impl Hashable for alloy::primitives::U256 {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        hasher.update(self.to_be_bytes::<32>());
+    }
+}
+
+impl Hashable for chrono::Duration {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        hasher.update(self.num_seconds().to_be_bytes());
+    }
+}
+
+impl Hashable for chrono::DateTime<chrono::Utc> {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        hasher.update(self.timestamp_millis().to_be_bytes());
+    }
+}

server/crates/arbiter-crypto/src/lib.rs

@@ -0,0 +1,7 @@
+#[cfg(feature = "authn")]
+pub mod authn;
+pub mod hashing;
+#[cfg(feature = "safecell")]
+pub mod safecell;
+
+pub use x_wing;

server/crates/arbiter-crypto/src/safecell.rs

@@ -0,0 +1,126 @@
+use memsafe::MemSafe;
+use std::{
+    any::type_name,
+    fmt,
+    ops::{Deref, DerefMut},
+};
+
+pub trait SafeCellHandle<T> {
+    type CellRead<'a>: Deref<Target = T>
+    where
+        Self: 'a,
+        T: 'a;
+    type CellWrite<'a>: Deref<Target = T> + DerefMut<Target = T>
+    where
+        Self: 'a,
+        T: 'a;
+
+    fn new(value: T) -> Self
+    where
+        Self: Sized;
+
+    fn read(&mut self) -> Self::CellRead<'_>;
+    fn write(&mut self) -> Self::CellWrite<'_>;
+
+    fn new_inline_default<F>(f: F) -> Self
+    where
+        Self: Sized,
+        T: Default,
+        F: for<'a> FnOnce(&'a mut T),
+    {
+        let mut cell = Self::new(T::default());
+        {
+            let mut handle = cell.write();
+            f(&mut *handle);
+        }
+        cell
+    }
+
+    fn new_inline<F>(f: Box<F>) -> Self
+    where
+        Self: Sized,
+        F: for<'a> FnOnce() -> T,
+    {
+        Self::new(f())
+    }
+
+    #[inline(always)]
+    fn read_inline<F, R>(&mut self, f: F) -> R
+    where
+        F: FnOnce(&T) -> R,
+    {
+        f(&*self.read())
+    }
+
+    #[inline(always)]
+    fn write_inline<F, R>(&mut self, f: F) -> R
+    where
+        F: FnOnce(&mut T) -> R,
+    {
+        f(&mut *self.write())
+    }
+}
+
+pub struct MemSafeCell<T>(MemSafe<T>);
+
+impl<T> fmt::Debug for MemSafeCell<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("MemSafeCell")
+            .field("inner", &format_args!("<protected {}>", type_name::<T>()))
+            .finish()
+    }
+}
+
+impl<T> SafeCellHandle<T> for MemSafeCell<T> {
+    type CellRead<'a>
+        = memsafe::MemSafeRead<'a, T>
+    where
+        Self: 'a,
+        T: 'a;
+    type CellWrite<'a>
+        = memsafe::MemSafeWrite<'a, T>
+    where
+        Self: 'a,
+        T: 'a;
+
+    fn new(value: T) -> Self {
+        match MemSafe::new(value) {
+            Ok(inner) => Self(inner),
+            Err(err) => {
+                // If protected memory cannot be allocated, process integrity is compromised.
+                abort_memory_breach("safe cell allocation", &err)
+            }
+        }
+    }
+
+    #[inline(always)]
+    fn read(&mut self) -> Self::CellRead<'_> {
+        match self.0.read() {
+            Ok(inner) => inner,
+            Err(err) => abort_memory_breach("safe cell read", &err),
+        }
+    }
+
+    #[inline(always)]
+    fn write(&mut self) -> Self::CellWrite<'_> {
+        match self.0.write() {
+            Ok(inner) => inner,
+            Err(err) => {
+                // If protected memory becomes unwritable here, treat it as a fatal memory breach.
+                abort_memory_breach("safe cell write", &err)
+            }
+        }
+    }
+}
+
+fn abort_memory_breach(action: &str, err: &memsafe::error::MemoryError) -> ! {
+    eprintln!("fatal {action}: {err}");
+    // SAFETY: Intentionally cause a segmentation fault to prevent further execution in a compromised state.
+    unsafe {
+        let unsafe_pointer = std::ptr::null_mut::<u8>();
+        std::ptr::write_volatile(unsafe_pointer, 0);
+    }
+    std::process::abort();
+}
+
+pub type SafeCell<T> = MemSafeCell<T>;

server/crates/arbiter-macros/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "arbiter-macros"
+version = "0.1.0"
+edition = "2024"
+
+[lib]
+proc-macro = true
+doctest = false
+
+[dependencies]
+proc-macro2 = "1.0"
+quote = "1.0"
+syn = { version = "2.0", features = ["derive", "fold", "full", "visit-mut"] }
+
+[dev-dependencies]
+arbiter-crypto = { path = "../arbiter-crypto" }
+
+[lints]
+workspace = true

server/crates/arbiter-macros/src/hashable.rs

@@ -0,0 +1,131 @@
+use crate::utils::{HASHABLE_TRAIT_PATH, HMAC_DIGEST_PATH};
+
+use proc_macro2::{Span, TokenStream, TokenTree};
+use quote::quote;
+use syn::{DataStruct, DeriveInput, Fields, Generics, Index, parse_quote, spanned::Spanned};
+
+pub(crate) fn derive(input: &DeriveInput) -> TokenStream {
+    match &input.data {
+        syn::Data::Struct(struct_data) => hashable_struct(input, struct_data),
+        syn::Data::Enum(_) => {
+            syn::Error::new_spanned(input, "Hashable can currently be derived only for structs")
+                .to_compile_error()
+        }
+        syn::Data::Union(_) => {
+            syn::Error::new_spanned(input, "Hashable cannot be derived for unions")
+                .to_compile_error()
+        }
+    }
+}
+
+fn hashable_struct(input: &DeriveInput, struct_data: &DataStruct) -> TokenStream {
+    let ident = &input.ident;
+    let hashable_trait = HASHABLE_TRAIT_PATH.to_path();
+    let hmac_digest = HMAC_DIGEST_PATH.to_path();
+    let generics = add_hashable_bounds(input.generics.clone(), &hashable_trait);
+    let field_accesses = collect_field_accesses(struct_data);
+    let hash_calls = build_hash_calls(&field_accesses, &hashable_trait);
+
+    let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
+
+    quote! {
+        #[automatically_derived]
+        impl #impl_generics #hashable_trait for #ident #ty_generics #where_clause {
+            fn hash<H: #hmac_digest>(&self, hasher: &mut H) {
+                #(#hash_calls)*
+            }
+        }
+    }
+}
+
+fn add_hashable_bounds(mut generics: Generics, hashable_trait: &syn::Path) -> Generics {
+    for type_param in generics.type_params_mut() {
+        type_param.bounds.push(parse_quote!(#hashable_trait));
+    }
+
+    generics
+}
+
+struct FieldAccess {
+    access: TokenStream,
+    span: Span,
+}
+
+fn collect_field_accesses(struct_data: &DataStruct) -> Vec<FieldAccess> {
+    match &struct_data.fields {
+        Fields::Named(fields) => {
+            // Keep deterministic alphabetical order for named fields.
+            // Do not remove this sort, because it keeps hash output stable regardless of source order.
+            let mut named_fields = fields
+                .named
+                .iter()
+                .map(|field| {
+                    let name = field
+                        .ident
+                        .as_ref()
+                        .expect("Fields::Named(fields) must have names")
+                        .clone();
+                    (name.to_string(), name)
+                })
+                .collect::<Vec<_>>();
+
+            named_fields.sort_by(|a, b| a.0.cmp(&b.0));
+
+            named_fields
+                .into_iter()
+                .map(|(_, name)| FieldAccess {
+                    access: quote! { #name },
+                    span: name.span(),
+                })
+                .collect()
+        }
+        Fields::Unnamed(fields) => fields
+            .unnamed
+            .iter()
+            .enumerate()
+            .map(|(i, field)| FieldAccess {
+                access: {
+                    let index = Index::from(i);
+                    quote! { #index }
+                },
+                span: field.ty.span(),
+            })
+            .collect(),
+        Fields::Unit => Vec::new(),
+    }
+}
+
+fn build_hash_calls(
+    field_accesses: &[FieldAccess],
+    hashable_trait: &syn::Path,
+) -> Vec<TokenStream> {
+    field_accesses
+        .iter()
+        .map(|field| {
+            let access = &field.access;
+            let call = quote! {
+                #hashable_trait::hash(&self.#access, hasher);
+            };
+
+            respan(call, field.span)
+        })
+        .collect()
+}
+
+/// Recursively set span on all tokens, including interpolated ones.
+fn respan(tokens: TokenStream, span: Span) -> TokenStream {
+    tokens
+        .into_iter()
+        .map(|tt| match tt {
+            TokenTree::Group(g) => {
+                let mut new = proc_macro2::Group::new(g.delimiter(), respan(g.stream(), span));
+                new.set_span(span);
+                TokenTree::Group(new)
+            }
+            mut other => {
+                other.set_span(span);
+                other
+            }
+        })
+        .collect()
+}

server/crates/arbiter-macros/src/lib.rs

@@ -0,0 +1,10 @@
+use syn::{DeriveInput, parse_macro_input};
+
+mod hashable;
+mod utils;
+
+#[proc_macro_derive(Hashable)]
+pub fn derive_hashable(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let input = parse_macro_input!(input as DeriveInput);
+    hashable::derive(&input).into()
+}

server/crates/arbiter-macros/src/utils.rs

@@ -0,0 +1,24 @@
+pub(crate) struct ToPath(pub &'static str);
+
+impl ToPath {
+    pub(crate) fn to_path(&self) -> syn::Path {
+        syn::parse_str(self.0).expect("Invalid path")
+    }
+}
+
+macro_rules! ensure_path {
+    ($path:path as $name:ident) => {
+        const _: () = {
+            #[cfg(test)]
+            #[expect(
+                unused_imports,
+                reason = "Ensures the path is valid and will cause a compile error if not"
+            )]
+            use $path as _;
+        };
+        pub(crate) const $name: ToPath = ToPath(stringify!($path));
+    };
+}
+
+ensure_path!(::arbiter_crypto::hashing::Hashable as HASHABLE_TRAIT_PATH);
+ensure_path!(::arbiter_crypto::hashing::Digest as HMAC_DIGEST_PATH);

server/crates/arbiter-proto/Cargo.toml

@@ -9,28 +9,27 @@ license = "Apache-2.0"
 tonic.workspace = true
 tokio.workspace = true
 futures.workspace = true
-hex = "0.4.3"
-tonic-prost = "0.14.3"
-prost = "0.14.3"
+tonic-prost = "0.14.5"
+prost.workspace = true
 kameo.workspace = true
 url = "2.5.8"
 miette.workspace = true
 thiserror.workspace = true
 rustls-pki-types.workspace = true
-base64 = "0.22.1"
+base64.workspace = true
 prost-types.workspace = true
-tracing.workspace = true
 async-trait.workspace = true
+tokio-stream.workspace = true
 
 [build-dependencies]
-tonic-prost-build = "0.14.3"
+tonic-prost-build = "0.14.5"
 
 [dev-dependencies]
 rstest.workspace = true
-rand.workspace = true
 rcgen.workspace = true
 
+[lib]
+doctest = false
+
 [package.metadata.cargo-shear]
-ignored = ["tonic-prost", "prost", "kameo"]
-
-
+ignored = ["tonic-prost", "prost"]

server/crates/arbiter-proto/build.rs

@@ -3,7 +3,6 @@ use tonic_prost_build::configure;
 static PROTOBUF_DIR: &str = "../../../protobufs";
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-
     println!("cargo::rerun-if-changed={PROTOBUF_DIR}");
 
     configure()
@@ -11,13 +10,12 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         .compile_protos(
             &[
                 format!("{}/arbiter.proto", PROTOBUF_DIR),
-                format!("{}/user_agent.proto", PROTOBUF_DIR),
+                format!("{}/operator.proto", PROTOBUF_DIR),
                 format!("{}/client.proto", PROTOBUF_DIR),
                 format!("{}/evm.proto", PROTOBUF_DIR),
             ],
             &[PROTOBUF_DIR.to_string()],
         )
-        
         .unwrap();
     Ok(())
 }

server/crates/arbiter-proto/src/lib.rs

@@ -1,17 +1,67 @@
 pub mod transport;
 pub mod url;
 
-use base64::{Engine, prelude::BASE64_STANDARD};
-
 pub mod proto {
     tonic::include_proto!("arbiter");
 
-    pub mod user_agent {
-        tonic::include_proto!("arbiter.user_agent");
+    pub mod shared {
+        tonic::include_proto!("arbiter.shared");
+
+        pub mod evm {
+            tonic::include_proto!("arbiter.shared.evm");
+        }
+    }
+
+    pub mod operator {
+        tonic::include_proto!("arbiter.operator");
+
+        pub mod auth {
+            tonic::include_proto!("arbiter.operator.auth");
+        }
+
+        pub mod evm {
+            tonic::include_proto!("arbiter.operator.evm");
+        }
+
+        pub mod governance {
+            tonic::include_proto!("arbiter.operator.governance");
+        }
+
+        pub mod sdk_client {
+            tonic::include_proto!("arbiter.operator.sdk_client");
+        }
+
+        pub mod vault {
+            tonic::include_proto!("arbiter.operator.vault");
+
+            pub mod bootstrap {
+                tonic::include_proto!("arbiter.operator.vault.bootstrap");
+            }
+
+            pub mod rekey {
+                tonic::include_proto!("arbiter.operator.vault.rekey");
+            }
+
+            pub mod unseal {
+                tonic::include_proto!("arbiter.operator.vault.unseal");
+            }
+        }
     }
 
     pub mod client {
         tonic::include_proto!("arbiter.client");
+
+        pub mod auth {
+            tonic::include_proto!("arbiter.client.auth");
+        }
+
+        pub mod evm {
+            tonic::include_proto!("arbiter.client.evm");
+        }
+
+        pub mod vault {
+            tonic::include_proto!("arbiter.client.vault");
+        }
     }
 
     pub mod evm {
@@ -19,6 +69,13 @@ pub mod proto {
     }
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ClientMetadata {
+    pub name: String,
+    pub description: Option<String>,
+    pub version: Option<String>,
+}
+
 pub static BOOTSTRAP_PATH: &str = "bootstrap_token";
 
 pub fn home_path() -> Result<std::path::PathBuf, std::io::Error> {
@@ -33,8 +90,3 @@ pub fn home_path() -> Result<std::path::PathBuf, std::io::Error> {
 
     Ok(arbiter_home)
 }
-
-pub fn format_challenge(nonce: i32, pubkey: &[u8]) -> Vec<u8> {
-    let concat_form = format!("{}:{}", nonce, BASE64_STANDARD.encode(pubkey));
-    concat_form.into_bytes()
-}

server/crates/arbiter-proto/src/transport.rs

@@ -1,257 +1,146 @@
-//! Transport-facing abstractions for protocol/session code.
+//! Transport-facing abstractions shared by protocol/session code.
 //!
-//! This module separates three concerns:
+//! This module defines a small set of transport traits that actors and other
+//! protocol code can depend on without knowing anything about the concrete
+//! transport underneath.
 //!
-//! - protocol/session logic wants a small duplex interface ([`Bi`])
-//! - transport adapters push concrete stream items to an underlying IO layer
-//! - transport boundaries translate between protocol-facing and transport-facing
-//!   item types via direction-specific converters
+//! The abstraction is split into:
+//! - [`Sender`] for outbound delivery
+//! - [`Receiver`] for inbound delivery
+//! - [`Bi`] as the combined duplex form (`Sender + Receiver`)
 //!
-//! [`Bi`] is intentionally minimal and transport-agnostic:
-//! - [`Bi::recv`] yields inbound protocol messages
-//! - [`Bi::send`] accepts outbound protocol/domain items
+//! This split lets code depend only on the half it actually needs. For
+//! example, some actor/session code only sends out-of-band messages, while
+//! auth/state-machine code may need full duplex access.
+//!
+//! [`Bi`] remains intentionally minimal and transport-agnostic:
+//! - [`Receiver::recv`] yields inbound messages
+//! - [`Sender::send`] accepts outbound messages
+//!
+//! Transport-specific adapters, including protobuf or gRPC bridges, live in the
+//! crates that own those boundaries rather than in `arbiter-proto`.
+//!
+//! [`Bi`] deliberately does not model request/response correlation. Some
+//! transports may carry multiplexed request/response traffic, some may emit
+//! out-of-band messages, and some may be one-message-at-a-time state machines.
+//! Correlation concerns such as request IDs, pending response maps, and
+//! out-of-band routing belong in the adapter or connection layer built on top
+//! of [`Bi`], not in this abstraction itself.
 //!
 //! # Generic Ordering Rule
 //!
-//! This module uses a single convention consistently: when a type or trait is
-//! parameterized by protocol message directions, the generic parameters are
-//! declared as `Inbound` first, then `Outbound`.
+//! This module consistently uses `Inbound` first and `Outbound` second in
+//! generic parameter lists.
 //!
-//! For [`Bi`], that means `Bi<Inbound, Outbound>`:
+//! For [`Receiver`], [`Sender`], and [`Bi`], this means:
+//! - `Receiver<Inbound>`
+//! - `Sender<Outbound>`
+//! - `Bi<Inbound, Outbound>`
+//!
+//! Concretely, for [`Bi`]:
 //! - `recv() -> Option<Inbound>`
 //! - `send(Outbound)`
 //!
-//! For adapter types that are parameterized by direction-specific converters,
-//! inbound-related converter parameters are declared before outbound-related
-//! converter parameters.
+//! [`expect_message`] is a small helper for linear protocol steps: it reads one
+//! inbound message from a transport and extracts a typed value from it, failing
+//! if the channel closes or the message shape is not what the caller expected.
 //!
-//! [`RecvConverter`] and [`SendConverter`] are infallible conversion traits used
-//! by adapters to map between protocol-facing and transport-facing item types.
-//! The traits themselves are not result-aware; adapters decide how transport
-//! errors are handled before (or instead of) conversion.
-//!
-//! [`grpc::GrpcAdapter`] combines:
-//! - a tonic inbound stream
-//! - a Tokio sender for outbound transport items
-//! - a [`RecvConverter`] for the receive path
-//! - a [`SendConverter`] for the send path
-//!
-//! [`DummyTransport`] is a no-op implementation useful for tests and local actor
-//! execution where no real network stream exists.
-//!
-//! # Component Interaction
-//!
-//! ```text
-//! inbound (network -> protocol)
-//! ============================
-//!
-//! tonic::Streaming<RecvTransport>
-//!     -> grpc::GrpcAdapter::recv()
-//!          |
-//!          +--> on `Ok(item)`: RecvConverter::convert(RecvTransport) -> Inbound
-//!          +--> on `Err(status)`: log error and close stream (`None`)
-//!     -> Bi::recv()
-//!     -> protocol/session actor
-//!
-//! outbound (protocol -> network)
-//! ==============================
-//!
-//! protocol/session actor
-//!     -> Bi::send(Outbound)
-//!     -> grpc::GrpcAdapter::send()
-//!          |
-//!          +--> SendConverter::convert(Outbound) -> SendTransport
-//!     -> Tokio mpsc::Sender<SendTransport>
-//!     -> tonic response stream
-//! ```
+//! [`DummyTransport`] is a no-op implementation useful for tests and local
+//! actor execution where no real stream exists.
 //!
 //! # Design Notes
 //!
-//! - `send()` returns [`Error`] only for transport delivery failures (for
-//!   example, when the outbound channel is closed).
-//! - [`grpc::GrpcAdapter`] logs tonic receive errors and treats them as stream
-//!   closure (`None`).
-//! - When protocol-facing and transport-facing types are identical, use
-//!   [`IdentityRecvConverter`] / [`IdentitySendConverter`].
-
-use std::marker::PhantomData;
-
+//! - [`Bi::send`] returns [`Error`] only for transport delivery failures, such
+//!   as a closed outbound channel.
+//! - [`Bi::recv`] returns `None` when the underlying transport closes.
+//! - Message translation is intentionally out of scope for this module.
 use async_trait::async_trait;
+use kameo::{error::Infallible, prelude::*};
+use std::marker::PhantomData;
 
 /// Errors returned by transport adapters implementing [`Bi`].
 #[derive(thiserror::Error, Debug)]
 pub enum Error {
     #[error("Transport channel is closed")]
     ChannelClosed,
+    #[error("Unexpected message received")]
+    UnexpectedMessage,
+}
+
+/// Receives one message from `transport` and extracts a value from it using
+/// `extractor`. Returns [`Error::ChannelClosed`] if the transport closes and
+/// [`Error::UnexpectedMessage`] if `extractor` returns `None`.
+pub async fn expect_message<T, Inbound, Outbound, Target, F>(
+    transport: &mut T,
+    extractor: F,
+) -> Result<Target, Error>
+where
+    T: Bi<Inbound, Outbound> + ?Sized,
+    F: FnOnce(Inbound) -> Option<Target>,
+{
+    let msg = transport.recv().await.ok_or(Error::ChannelClosed)?;
+    extractor(msg).ok_or(Error::UnexpectedMessage)
+}
+
+#[async_trait]
+pub trait Sender<Outbound>: Send + Sync {
+    async fn send(&mut self, item: Outbound) -> Result<(), Error>;
+}
+
+#[async_trait]
+pub trait Receiver<Inbound>: Send + Sync {
+    async fn recv(&mut self) -> Option<Inbound>;
 }
 
 /// Minimal bidirectional transport abstraction used by protocol code.
 ///
-/// `Bi<Inbound, Outbound>` models a duplex channel with:
+/// `Bi<Inbound, Outbound>` is the combined duplex form of [`Sender`] and
+/// [`Receiver`].
+///
+/// It models a channel with:
 /// - inbound items of type `Inbound` read via [`Bi::recv`]
 /// - outbound items of type `Outbound` written via [`Bi::send`]
+///
+/// It does not imply request/response sequencing, one-at-a-time exchange, or
+/// any built-in correlation mechanism between inbound and outbound items.
+pub trait Bi<Inbound, Outbound>: Sender<Outbound> + Receiver<Inbound> + Send + Sync {}
+
 #[async_trait]
-pub trait Bi<Inbound, Outbound>: Send + Sync + 'static {
-    async fn send(&mut self, item: Outbound) -> Result<(), Error>;
-
-    async fn recv(&mut self) -> Option<Inbound>;
-}
-
-/// Converts transport-facing inbound items into protocol-facing inbound items.
-pub trait RecvConverter: Send + Sync + 'static {
-    type Input;
-    type Output;
-
-    fn convert(&self, item: Self::Input) -> Self::Output;
-}
-
-/// Converts protocol/domain outbound items into transport-facing outbound items.
-pub trait SendConverter: Send + Sync + 'static {
-    type Input;
-    type Output;
-
-    fn convert(&self, item: Self::Input) -> Self::Output;
-}
-
-/// A [`RecvConverter`] that forwards values unchanged.
-pub struct IdentityRecvConverter<T> {
-    _marker: PhantomData<T>,
-}
-
-impl<T> IdentityRecvConverter<T> {
-    pub fn new() -> Self {
-        Self {
-            _marker: PhantomData,
-        }
-    }
-}
-
-impl<T> Default for IdentityRecvConverter<T> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl<T> RecvConverter for IdentityRecvConverter<T>
+impl<T, Outbound> Sender<Outbound> for &mut T
 where
-    T: Send + Sync + 'static,
+    T: Sender<Outbound> + ?Sized,
+    Outbound: Send + 'static,
 {
-    type Input = T;
-    type Output = T;
-
-    fn convert(&self, item: Self::Input) -> Self::Output {
-        item
+    async fn send(&mut self, item: Outbound) -> Result<(), Error> {
+        (**self).send(item).await
     }
 }
 
-/// A [`SendConverter`] that forwards values unchanged.
-pub struct IdentitySendConverter<T> {
-    _marker: PhantomData<T>,
-}
-
-impl<T> IdentitySendConverter<T> {
-    pub fn new() -> Self {
-        Self {
-            _marker: PhantomData,
-        }
-    }
-}
-
-impl<T> Default for IdentitySendConverter<T> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl<T> SendConverter for IdentitySendConverter<T>
+#[async_trait]
+impl<T, Inbound> Receiver<Inbound> for &mut T
 where
-    T: Send + Sync + 'static,
+    T: Receiver<Inbound> + ?Sized,
+    Inbound: Send + 'static,
 {
-    type Input = T;
-    type Output = T;
-
-    fn convert(&self, item: Self::Input) -> Self::Output {
-        item
+    async fn recv(&mut self) -> Option<Inbound> {
+        (**self).recv().await
     }
 }
 
-/// gRPC-specific transport adapters and helpers.
-pub mod grpc {
-    use async_trait::async_trait;
-    use futures::StreamExt;
-    use tokio::sync::mpsc;
-    use tonic::Streaming;
+impl<T, Inbound, Outbound> Bi<Inbound, Outbound> for &mut T
+where
+    T: Bi<Inbound, Outbound> + ?Sized,
+    Inbound: Send + 'static,
+    Outbound: Send + 'static,
+{
+}
 
-    use super::{Bi, Error, RecvConverter, SendConverter};
+pub trait SplittableBi<Inbound, Outbound>: Bi<Inbound, Outbound> {
+    type Sender: Sender<Outbound>;
+    type Receiver: Receiver<Inbound>;
 
-    /// [`Bi`] adapter backed by a tonic gRPC bidirectional stream.
-    ///
-
-    /// Tonic receive errors are logged and treated as stream closure (`None`).
-    /// The receive converter is only invoked for successful inbound transport
-    /// items.
-    pub struct GrpcAdapter<InboundConverter, OutboundConverter>
-    where
-        InboundConverter: RecvConverter,
-        OutboundConverter: SendConverter,
-    {
-        sender: mpsc::Sender<OutboundConverter::Output>,
-        receiver: Streaming<InboundConverter::Input>,
-        inbound_converter: InboundConverter,
-        outbound_converter: OutboundConverter,
-    }
-
-    impl<InboundTransport, Inbound, InboundConverter, OutboundConverter>
-        GrpcAdapter<InboundConverter, OutboundConverter>
-    where
-        InboundConverter: RecvConverter<Input = InboundTransport, Output = Inbound>,
-        OutboundConverter: SendConverter,
-    {
-        pub fn new(
-            sender: mpsc::Sender<OutboundConverter::Output>,
-            receiver: Streaming<InboundTransport>,
-            inbound_converter: InboundConverter,
-            outbound_converter: OutboundConverter,
-        ) -> Self {
-            Self {
-                sender,
-                receiver,
-                inbound_converter,
-                outbound_converter,
-            }
-        }
-    }
-
-    #[async_trait]
-    impl<InboundConverter, OutboundConverter> Bi<InboundConverter::Output, OutboundConverter::Input>
-        for GrpcAdapter<InboundConverter, OutboundConverter>
-    where
-        InboundConverter: RecvConverter,
-        OutboundConverter: SendConverter,
-        OutboundConverter::Input: Send + 'static,
-        OutboundConverter::Output: Send + 'static,
-    {
-        #[tracing::instrument(level = "trace", skip(self, item))]
-        async fn send(&mut self, item: OutboundConverter::Input) -> Result<(), Error> {
-            let outbound = self.outbound_converter.convert(item);
-            self.sender
-                .send(outbound)
-                .await
-                .map_err(|_| Error::ChannelClosed)
-        }
-
-        #[tracing::instrument(level = "trace", skip(self))]
-        async fn recv(&mut self) -> Option<InboundConverter::Output> {
-            match self.receiver.next().await {
-                Some(Ok(item)) => Some(self.inbound_converter.convert(item)),
-                Some(Err(error)) => {
-                    tracing::error!(error = ?error, "grpc transport recv failed; closing stream");
-                    None
-                }
-                None => None,
-            }
-        }
-    }
+    fn split(self) -> (Self::Sender, Self::Receiver);
+    fn from_parts(sender: Self::Sender, receiver: Self::Receiver) -> Self;
 }
 
 /// No-op [`Bi`] transport for tests and manual actor usage.
@@ -262,22 +151,16 @@ pub struct DummyTransport<Inbound, Outbound> {
     _marker: PhantomData<(Inbound, Outbound)>,
 }
 
-impl<Inbound, Outbound> DummyTransport<Inbound, Outbound> {
-    pub fn new() -> Self {
+impl<Inbound, Outbound> Default for DummyTransport<Inbound, Outbound> {
+    fn default() -> Self {
         Self {
             _marker: PhantomData,
         }
     }
 }
 
-impl<Inbound, Outbound> Default for DummyTransport<Inbound, Outbound> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
 #[async_trait]
-impl<Inbound, Outbound> Bi<Inbound, Outbound> for DummyTransport<Inbound, Outbound>
+impl<Inbound, Outbound> Sender<Outbound> for DummyTransport<Inbound, Outbound>
 where
     Inbound: Send + Sync + 'static,
     Outbound: Send + Sync + 'static,
@@ -285,9 +168,51 @@ where
     async fn send(&mut self, _item: Outbound) -> Result<(), Error> {
         Ok(())
     }
+}
 
+#[async_trait]
+impl<Inbound, Outbound> Receiver<Inbound> for DummyTransport<Inbound, Outbound>
+where
+    Inbound: Send + Sync + 'static,
+    Outbound: Send + Sync + 'static,
+{
     async fn recv(&mut self) -> Option<Inbound> {
         std::future::pending::<()>().await;
         None
     }
 }
+
+impl<Inbound, Outbound> Bi<Inbound, Outbound> for DummyTransport<Inbound, Outbound>
+where
+    Inbound: Send + Sync + 'static,
+    Outbound: Send + Sync + 'static,
+{
+}
+
+pub mod grpc;
+
+#[derive(thiserror::Error, Debug)]
+pub enum ForwardError<I> {
+    #[error("Transport error: {0}")]
+    Transport(#[from] Error),
+    #[error("Actor delivery error: {0}")]
+    Actor(SendError<I>),
+}
+
+pub async fn forward_to_actor<Transport, Inbound, Outbound, Handler>(
+    transport: &mut Transport,
+    actor: &ActorRef<Handler>,
+) -> Result<(), ForwardError<Inbound>>
+where
+    Transport: Bi<Inbound, <Outbound as Reply>::Ok>,
+    Handler: Actor + Message<Inbound, Reply = Outbound>,
+    Inbound: Send + 'static,
+    Outbound: Send + 'static + Reply<Error = Infallible>, // `Infallible` to enforce contract that `Outbound` carries handler-level error
+{
+    while let Some(request) = transport.recv().await {
+        let resp = actor.ask(request).await.map_err(ForwardError::Actor)?;
+        transport.send(resp).await?
+    }
+
+    Err(Error::ChannelClosed.into())
+}

server/crates/arbiter-proto/src/transport/grpc.rs

@@ -0,0 +1,106 @@
+use super::{Bi, Receiver, Sender};
+
+use async_trait::async_trait;
+use futures::StreamExt;
+use tokio::sync::mpsc;
+use tokio_stream::wrappers::ReceiverStream;
+
+pub struct GrpcSender<Outbound> {
+    tx: mpsc::Sender<Result<Outbound, tonic::Status>>,
+}
+
+#[async_trait]
+impl<Outbound> Sender<Result<Outbound, tonic::Status>> for GrpcSender<Outbound>
+where
+    Outbound: Send + Sync + 'static,
+{
+    async fn send(&mut self, item: Result<Outbound, tonic::Status>) -> Result<(), super::Error> {
+        self.tx
+            .send(item)
+            .await
+            .map_err(|_| super::Error::ChannelClosed)
+    }
+}
+
+pub struct GrpcReceiver<Inbound> {
+    rx: tonic::Streaming<Inbound>,
+}
+#[async_trait]
+impl<Inbound> Receiver<Result<Inbound, tonic::Status>> for GrpcReceiver<Inbound>
+where
+    Inbound: Send + Sync + 'static,
+{
+    async fn recv(&mut self) -> Option<Result<Inbound, tonic::Status>> {
+        self.rx.next().await
+    }
+}
+
+pub struct GrpcBi<Inbound, Outbound> {
+    sender: GrpcSender<Outbound>,
+    receiver: GrpcReceiver<Inbound>,
+}
+
+impl<Inbound, Outbound> GrpcBi<Inbound, Outbound>
+where
+    Inbound: Send + Sync + 'static,
+    Outbound: Send + Sync + 'static,
+{
+    pub fn from_bi_stream(
+        receiver: tonic::Streaming<Inbound>,
+    ) -> (Self, ReceiverStream<Result<Outbound, tonic::Status>>) {
+        let (tx, rx) = mpsc::channel(10);
+        let sender = GrpcSender { tx };
+        let receiver = GrpcReceiver { rx: receiver };
+        let bi = GrpcBi { sender, receiver };
+        (bi, ReceiverStream::new(rx))
+    }
+}
+
+#[async_trait]
+impl<Inbound, Outbound> Sender<Result<Outbound, tonic::Status>> for GrpcBi<Inbound, Outbound>
+where
+    Inbound: Send + Sync + 'static,
+    Outbound: Send + Sync + 'static,
+{
+    async fn send(&mut self, item: Result<Outbound, tonic::Status>) -> Result<(), super::Error> {
+        self.sender.send(item).await
+    }
+}
+
+#[async_trait]
+impl<Inbound, Outbound> Receiver<Result<Inbound, tonic::Status>> for GrpcBi<Inbound, Outbound>
+where
+    Inbound: Send + Sync + 'static,
+    Outbound: Send + Sync + 'static,
+{
+    async fn recv(&mut self) -> Option<Result<Inbound, tonic::Status>> {
+        self.receiver.recv().await
+    }
+}
+
+impl<Inbound, Outbound> Bi<Result<Inbound, tonic::Status>, Result<Outbound, tonic::Status>>
+    for GrpcBi<Inbound, Outbound>
+where
+    Inbound: Send + Sync + 'static,
+    Outbound: Send + Sync + 'static,
+{
+}
+
+impl<Inbound, Outbound>
+    super::SplittableBi<Result<Inbound, tonic::Status>, Result<Outbound, tonic::Status>>
+    for GrpcBi<Inbound, Outbound>
+where
+    Inbound: Send + Sync + 'static,
+    Outbound: Send + Sync + 'static,
+{
+    type Sender = GrpcSender<Outbound>;
+    type Receiver = GrpcReceiver<Inbound>;
+
+    fn split(self) -> (Self::Sender, Self::Receiver) {
+        (self.sender, self.receiver)
+    }
+
+    fn from_parts(sender: Self::Sender, receiver: Self::Receiver) -> Self {
+        GrpcBi { sender, receiver }
+    }
+}

server/crates/arbiter-proto/src/url.rs

@@ -1,12 +1,12 @@
-use std::fmt::Display;
-
 use base64::{Engine as _, prelude::BASE64_URL_SAFE};
 use rustls_pki_types::CertificateDer;
+use std::fmt::Display;
 
 const ARBITER_URL_SCHEME: &str = "arbiter";
 const CERT_QUERY_KEY: &str = "cert";
 const BOOTSTRAP_TOKEN_QUERY_KEY: &str = "bootstrap_token";
 
+#[derive(Debug, Clone)]
 pub struct ArbiterUrl {
     pub host: String,
     pub port: u16,
@@ -20,7 +20,7 @@ impl Display for ArbiterUrl {
             "{ARBITER_URL_SCHEME}://{}:{}?{CERT_QUERY_KEY}={}",
             self.host,
             self.port,
-            BASE64_URL_SAFE.encode(self.ca_cert.to_vec())
+            BASE64_URL_SAFE.encode(&self.ca_cert)
         );
         if let Some(token) = &self.bootstrap_token {
             base.push_str(&format!("&{BOOTSTRAP_TOKEN_QUERY_KEY}={}", token));
@@ -104,7 +104,7 @@ mod tests {
 
     #[rstest]
 
-    fn test_parsing_correctness(
+    fn parsing_correctness(
         #[values("127.0.0.1", "localhost", "192.168.1.1", "some.domain.com")] host: &str,
 
         #[values(None, Some("token123".to_string()))] bootstrap_token: Option<String>,

server/crates/arbiter-server/Cargo.toml

@@ -5,16 +5,20 @@ edition = "2024"
 repository = "https://git.markettakers.org/MarketTakers/arbiter"
 license = "Apache-2.0"
 
+[lints]
+workspace = true
+
 [dependencies]
-diesel = { version = "2.3.6", features = ["chrono", "returning_clauses_for_sqlite_3_35", "serde_json", "time", "uuid"] }
-diesel-async = { version = "0.7.4", features = [
+diesel = { version = "2.3.9", features = ["chrono", "returning_clauses_for_sqlite_3_35", "serde_json", "time", "uuid"] }
+diesel-async = { version = "0.9.0", features = [
     "bb8",
     "migrations",
     "sqlite",
     "tokio",
 ] }
-ed25519-dalek.workspace = true
 arbiter-proto.path = "../arbiter-proto"
+arbiter-crypto.path = "../arbiter-crypto"
+arbiter-macros.path = "../arbiter-macros"
 tracing.workspace = true
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 tonic.workspace = true
@@ -22,30 +26,41 @@ tonic.features = ["tls-aws-lc"]
 tokio.workspace = true
 rustls.workspace = true
 smlang.workspace = true
-miette.workspace = true
 thiserror.workspace = true
-diesel_migrations = { version = "2.3.1", features = ["sqlite"] }
+diesel_migrations = { version = "2.3.2", features = ["sqlite"] }
 async-trait.workspace = true
-secrecy = "0.10.3"
-futures.workspace = true
 tokio-stream.workspace = true
-dashmap = "6.1.0"
 rand.workspace = true
 rcgen.workspace = true
 chrono.workspace = true
-memsafe = "0.4.0"
-zeroize = { version = "1.8.2", features = ["std", "simd"] }
 kameo.workspace = true
-x25519-dalek.workspace = true
 chacha20poly1305 = { version = "0.10.1", features = ["std"] }
 argon2 = { version = "0.5.3", features = ["zeroize"] }
 restructed = "0.2.2"
-strum = { version = "0.27.2", features = ["derive"] }
+strum.workspace = true
 pem = "3.0.6"
-k256 = "0.13.4"
+sha2.workspace = true
+hmac.workspace = true
 alloy.workspace = true
+prost.workspace = true
+prost-types.workspace = true
 arbiter-tokens-registry.path = "../arbiter-tokens-registry"
+anyhow = "1.0.102"
+mutants.workspace = true
+subtle = "2.6.1"
+x25519-dalek.workspace = true
+k256.workspace = true
+kameo_actors.workspace = true
+vsss-rs = "5.4.0"
+rand_core = "0.6"
 
 [dev-dependencies]
-insta = "1.46.3"
+proptest = "1.11.0"
+rstest.workspace = true
 test-log = { version = "0.2", default-features = false, features = ["trace"] }
+ml-dsa.workspace = true
+mockall = "0.15.0"
+tempfile = "3.27.0"
+
+[lib]
+doctest = false

server/crates/arbiter-server/migrations/2026-02-14-171124-0000_init/up.sql

@@ -28,7 +28,7 @@ create table if not exists tls_history (
     id INTEGER not null PRIMARY KEY,
     cert text not null,
     cert_key text not null, -- PEM Encoded private key
-    ca_cert text not null, 
+    ca_cert text not null,
     ca_key text not null, -- PEM Encoded private key
     created_at integer not null default(unixepoch ('now'))
 ) STRICT;
@@ -37,27 +37,67 @@ create table if not exists tls_history (
 create table if not exists arbiter_settings (
     id INTEGER not null PRIMARY KEY CHECK (id = 1), -- singleton row, id must be 1
     root_key_id integer references root_key_history (id) on delete RESTRICT, -- if null, means wasn't bootstrapped yet
-    tls_id integer references tls_history (id) on delete RESTRICT
+    tls_id integer references tls_history (id) on delete RESTRICT,
+    -- Shamir threshold of the split that produced the stored shares. Null before bootstrap.
+    -- Recorded rather than recomputed: an aborted operator replacement leaves fewer share
+    -- rows than the split has shares, and a recomputed threshold would then be wrong.
+    shamir_threshold integer
 ) STRICT;
 
-insert into arbiter_settings (id) values (1) on conflict do nothing; -- ensure singleton row exists
+insert into arbiter_settings (id) values (1) on conflict do nothing;
+-- ensure singleton row exists
 
-create table if not exists useragent_client (
+create table if not exists operator_identity (
     id integer not null primary key,
-    nonce integer not null default(1), -- used for auth challenge
     public_key blob not null,
     created_at integer not null default(unixepoch ('now')),
     updated_at integer not null default(unixepoch ('now'))
 ) STRICT;
+create unique index if not exists uniq_operator_identity_public_key on operator_identity (public_key);
+
+create table if not exists operator (
+    id integer primary key references operator_identity(id) on delete restrict, -- same id as operator_identity
+
+    share blob not null,
+    share_nonce blob not null,
+    share_salt blob not null,
+
+    created_at integer not null default(unixepoch ('now')),
+    updated_at integer not null default(unixepoch ('now'))
+
+) STRICT;
+
+create table if not exists client_metadata (
+    id integer not null primary key,
+    name text not null, -- human-readable name for the client
+    description text, -- optional description for the client
+    version text, -- client version for tracking and debugging
+    created_at integer not null default(unixepoch ('now'))
+) STRICT;
+
+-- created to track history of changes
+create table if not exists client_metadata_history (
+    id integer not null primary key,
+    metadata_id integer not null references client_metadata (id) on delete cascade,
+    client_id integer not null references program_client (id) on delete cascade,
+    created_at integer not null default(unixepoch ('now'))
+) STRICT;
+
+create unique index if not exists uniq_metadata_binding_client on client_metadata_history (client_id);
 
 create table if not exists program_client (
     id integer not null primary key,
-    nonce integer not null default(1), -- used for auth challenge
     public_key blob not null,
+    metadata_id integer not null references client_metadata (id) on delete cascade,
     created_at integer not null default(unixepoch ('now')),
     updated_at integer not null default(unixepoch ('now'))
 ) STRICT;
 
+create unique index if not exists program_client_public_key_unique
+    on program_client (public_key);
+
+create unique index if not exists uniq_program_client_public_key on program_client (public_key);
+
 create table if not exists evm_wallet (
     id integer not null primary key,
     address blob not null, -- 20-byte Ethereum address
@@ -66,93 +106,271 @@ create table if not exists evm_wallet (
 ) STRICT;
 
 create unique index if not exists uniq_evm_wallet_address on evm_wallet (address);
+
 create unique index if not exists uniq_evm_wallet_aead on evm_wallet (aead_encrypted_id);
 
+create table if not exists evm_wallet_access (
+    id integer not null primary key,
+    wallet_id integer not null references evm_wallet (id) on delete cascade,
+    client_id integer not null references program_client (id) on delete cascade,
+    revoked_at integer, -- unix timestamp when revoked, null = still active
+    created_at integer not null default(unixepoch ('now'))
+) STRICT;
+
+create unique index if not exists uniq_wallet_access on evm_wallet_access (wallet_id, client_id);
+
 create table if not exists evm_ether_transfer_limit (
     id integer not null primary key,
-    window_secs integer not null,           -- window duration in seconds
-    max_volume blob not null                -- big-endian 32-byte U256
+    window_secs integer not null, -- window duration in seconds
+    max_volume blob not null -- big-endian 32-byte U256
 ) STRICT;
 
 -- Shared grant properties: client scope, timeframe, fee caps, and rate limit
 create table if not exists evm_basic_grant (
     id integer not null primary key,
-    wallet_id integer not null references evm_wallet(id) on delete restrict, 
-    client_id integer not null references program_client(id) on delete restrict,
-    chain_id integer not null,              -- EIP-155 chain ID
-    valid_from integer,                     -- unix timestamp (seconds), null = no lower bound
-    valid_until integer,                    -- unix timestamp (seconds), null = no upper bound
-    max_gas_fee_per_gas blob,               -- big-endian 32-byte U256, null = unlimited
-    max_priority_fee_per_gas blob,          -- big-endian 32-byte U256, null = unlimited
-    rate_limit_count integer,               -- max transactions in window, null = unlimited
-    rate_limit_window_secs integer,         -- window duration in seconds, null = unlimited
-    revoked_at integer,                     -- unix timestamp when revoked, null = still active
-    created_at integer not null default(unixepoch('now'))
+    wallet_access_id integer not null references evm_wallet_access (id) on delete restrict,
+    chain_id integer not null, -- EIP-155 chain ID
+    valid_from integer, -- unix timestamp (seconds), null = no lower bound
+    valid_until integer, -- unix timestamp (seconds), null = no upper bound
+    max_gas_fee_per_gas blob, -- big-endian 32-byte U256, null = unlimited
+    max_priority_fee_per_gas blob, -- big-endian 32-byte U256, null = unlimited
+    rate_limit_count integer, -- max transactions in window, null = unlimited
+    rate_limit_window_secs integer, -- window duration in seconds, null = unlimited
+    revoked_at integer, -- unix timestamp when revoked, null = still active
+    created_at integer not null default(unixepoch ('now'))
 ) STRICT;
 
 -- Shared transaction log for all EVM grants, used for rate limit tracking and auditing
 create table if not exists evm_transaction_log (
     id integer not null primary key,
-    grant_id integer not null references evm_basic_grant(id) on delete restrict,
-    client_id integer not null references program_client(id) on delete restrict,
-    wallet_id integer not null references evm_wallet(id) on delete restrict,
+    wallet_access_id integer not null references evm_wallet_access (id) on delete restrict,
+    grant_id integer not null references evm_basic_grant (id) on delete restrict,
     chain_id integer not null,
-    eth_value blob not null,     -- always present on any EVM tx
-    signed_at integer not null default(unixepoch('now'))
+    eth_value blob not null, -- always present on any EVM tx
+    signed_at integer not null default(unixepoch ('now'))
 ) STRICT;
 
-create index if not exists idx_evm_basic_grant_wallet_chain on evm_basic_grant(client_id, wallet_id, chain_id);
+create index if not exists idx_evm_basic_grant_access_chain on evm_basic_grant (wallet_access_id, chain_id);
 
 -- ===============================
 -- ERC20 token transfer grant
 -- ===============================
 create table if not exists evm_token_transfer_grant (
     id integer not null primary key,
-    basic_grant_id integer not null unique references evm_basic_grant(id) on delete cascade,
-    token_contract blob not null,            -- 20-byte ERC20 contract address
-    receiver blob                            -- 20-byte recipient address or null if every recipient allowed
+    basic_grant_id integer not null unique references evm_basic_grant (id) on delete cascade,
+    token_contract blob not null, -- 20-byte ERC20 contract address
+    receiver blob -- 20-byte recipient address or null if every recipient allowed
 ) STRICT;
 
 -- Per-window volume limits for token transfer grants
 create table if not exists evm_token_transfer_volume_limit (
     id integer not null primary key,
-    grant_id integer not null references evm_token_transfer_grant(id) on delete cascade,
-    window_secs integer not null,           -- window duration in seconds
-    max_volume blob not null                -- big-endian 32-byte U256
+    grant_id integer not null references evm_token_transfer_grant (id) on delete cascade,
+    window_secs integer not null, -- window duration in seconds
+    max_volume blob not null -- big-endian 32-byte U256
 ) STRICT;
 
 -- Log table for token transfer grant usage
 create table if not exists evm_token_transfer_log (
     id integer not null primary key,
-    grant_id integer not null references evm_token_transfer_grant(id) on delete restrict,
-    log_id integer not null references evm_transaction_log(id) on delete restrict,
-    chain_id integer not null,              -- EIP-155 chain ID
-    token_contract blob not null,           -- 20-byte ERC20 contract address
-    recipient_address blob not null,        -- 20-byte recipient address
-    value blob not null,                    -- big-endian 32-byte U256
-    created_at integer not null default(unixepoch('now'))
+    grant_id integer not null references evm_token_transfer_grant (id) on delete restrict,
+    log_id integer not null references evm_transaction_log (id) on delete restrict,
+    chain_id integer not null, -- EIP-155 chain ID
+    token_contract blob not null, -- 20-byte ERC20 contract address
+    recipient_address blob not null, -- 20-byte recipient address
+    value blob not null, -- big-endian 32-byte U256
+    created_at integer not null default(unixepoch ('now'))
 ) STRICT;
 
-create index if not exists idx_token_transfer_log_grant on evm_token_transfer_log(grant_id);
-create index if not exists idx_token_transfer_log_log_id on evm_token_transfer_log(log_id);
-create index if not exists idx_token_transfer_log_chain on evm_token_transfer_log(chain_id);
+create index if not exists idx_token_transfer_log_grant on evm_token_transfer_log (grant_id);
 
+create index if not exists idx_token_transfer_log_log_id on evm_token_transfer_log (log_id);
+
+create index if not exists idx_token_transfer_log_chain on evm_token_transfer_log (chain_id);
 
 -- ===============================
 -- Ether transfer grant (uses base log)
 -- ===============================
 create table if not exists evm_ether_transfer_grant (
     id integer not null primary key,
-    basic_grant_id integer not null unique references evm_basic_grant(id) on delete cascade,
-    limit_id integer not null references evm_ether_transfer_limit(id) on delete restrict
+    basic_grant_id integer not null unique references evm_basic_grant (id) on delete cascade,
+    limit_id integer not null references evm_ether_transfer_limit (id) on delete restrict
 ) STRICT;
 
 -- Specific recipient addresses for an ether transfer grant
 create table if not exists evm_ether_transfer_grant_target (
     id integer not null primary key,
-    grant_id integer not null references evm_ether_transfer_grant(id) on delete cascade,
-    address blob not null                   -- 20-byte recipient address
+    grant_id integer not null references evm_ether_transfer_grant (id) on delete cascade,
+    address blob not null -- 20-byte recipient address
 ) STRICT;
 
-create unique index if not exists uniq_ether_transfer_target on evm_ether_transfer_grant_target(grant_id, address);
+create unique index if not exists uniq_ether_transfer_target on evm_ether_transfer_grant_target (grant_id, address);
 
+-- ===============================
+-- Integrity Envelopes
+-- ===============================
+create table if not exists integrity_envelope (
+    id integer not null primary key,
+    entity_kind text not null,
+    entity_id blob not null,
+    payload_version integer not null,
+    key_version integer not null,
+    mac blob not null, -- 20-byte recipient address
+    signed_at integer not null default(unixepoch ('now')),
+    created_at integer not null default(unixepoch ('now'))
+) STRICT;
+
+create unique index if not exists uniq_integrity_envelope_entity on integrity_envelope (entity_kind, entity_id);
+
+create table if not exists proposal (
+    id           integer not null primary key,
+    kind         text    not null,
+    initiator_id integer not null references operator_identity(id) on delete restrict,
+    created_at   integer not null default(unixepoch('now')),
+    expires_at   integer not null,
+    status       text    not null default 'pending'
+        check (status in ('pending', 'approved', 'rejected'))
+) STRICT;
+
+-- Parameters of an approved-or-pending proposal
+create table if not exists proposal_approve_sdk_client (
+    proposal_id integer not null primary key references proposal(id) on delete cascade,
+    client_id   integer not null references program_client(id) on delete restrict
+) STRICT;
+
+create table if not exists proposal_grant_wallet_access (
+    proposal_id integer not null primary key references proposal(id) on delete cascade,
+    wallet_id   integer not null references evm_wallet(id) on delete restrict,
+    client_id   integer not null references program_client(id) on delete restrict
+) STRICT;
+
+create table if not exists proposal_replace_operator (
+    proposal_id     integer not null primary key references proposal(id) on delete cascade,
+    old_operator_id integer not null references operator_identity(id) on delete restrict,
+    new_pubkey      blob    not null
+) STRICT;
+
+-- The transaction an operator votes to sign.
+create table if not exists proposal_one_off_transaction (
+    proposal_id              integer not null primary key references proposal(id) on delete cascade,
+    client_id                integer not null references program_client(id) on delete restrict,
+    wallet_address           blob    not null check (length(wallet_address) = 20),
+    chain_id                 integer not null,
+    nonce                    integer not null,
+    gas_limit                integer not null,
+    max_fee_per_gas          blob    not null check (length(max_fee_per_gas) = 16),
+    max_priority_fee_per_gas blob    not null check (length(max_priority_fee_per_gas) = 16),
+    to_address               blob    not null check (length(to_address) = 20),
+    value                    blob    not null check (length(value) = 32),
+    input                    blob    not null
+) STRICT;
+
+-- The grant an operator votes to creat
+create table if not exists proposal_persistent_grant (
+    proposal_id              integer not null primary key references proposal (id) on delete cascade,
+    wallet_access_id         integer not null references evm_wallet_access (id) on delete restrict,
+    chain_id                 integer not null, -- EIP-155 chain ID
+    valid_from               integer, -- unix timestamp (seconds), null = no lower bound
+    valid_until              integer, -- unix timestamp (seconds), null = no upper bound
+    max_gas_fee_per_gas      blob check (max_gas_fee_per_gas is null or length(max_gas_fee_per_gas) = 32),
+    max_priority_fee_per_gas blob check (max_priority_fee_per_gas is null or length(max_priority_fee_per_gas) = 32),
+    rate_limit_count         integer, -- max transactions in window, null = unlimited
+    rate_limit_window_secs   integer, -- window duration in seconds, null = unlimited
+    check ((rate_limit_count is null) = (rate_limit_window_secs is null))
+) STRICT;
+
+-- `specific = ether_transfer`
+create table if not exists proposal_persistent_grant_ether (
+    proposal_id integer not null primary key references proposal_persistent_grant (proposal_id) on delete cascade,
+    window_secs integer not null,
+    max_volume  blob    not null check (length(max_volume) = 32)
+) STRICT;
+
+create table if not exists proposal_persistent_grant_ether_target (
+    id          integer not null primary key,
+    proposal_id integer not null references proposal_persistent_grant_ether (proposal_id) on delete cascade,
+    address     blob    not null check (length(address) = 20)
+) STRICT;
+
+create unique index if not exists uniq_proposal_ether_target on proposal_persistent_grant_ether_target (proposal_id, address);
+
+-- `specific = token_transfer`
+create table if not exists proposal_persistent_grant_token (
+    proposal_id    integer not null primary key references proposal_persistent_grant (proposal_id) on delete cascade,
+    token_contract blob    not null check (length(token_contract) = 20),
+    receiver       blob check (receiver is null or length(receiver) = 20)
+) STRICT;
+
+create table if not exists proposal_persistent_grant_token_limit (
+    id          integer not null primary key,
+    proposal_id integer not null references proposal_persistent_grant_token (proposal_id) on delete cascade,
+    window_secs integer not null,
+    max_volume  blob    not null check (length(max_volume) = 32)
+) STRICT;
+
+create table if not exists proposal_vote (
+    id          integer not null primary key,
+    proposal_id integer not null references proposal(id) on delete cascade,
+    operator_id integer not null references operator_identity(id) on delete restrict,
+    approve     integer not null check (approve in (0, 1)),
+    signature   blob    not null,
+    voted_at    integer not null default(unixepoch('now')),
+    unique (proposal_id, operator_id)
+) STRICT;
+
+
+-- The signature the vault produced for an approved transaction, by component.
+--
+-- secp256k1 signatures have three common encodings (Electrum v=27/28, raw parity,
+-- ERC-2098 compact); a single blob would not say which one it holds. `y_parity` is
+-- the raw bit -- add 27 to rebuild the Electrum form `Signature::as_bytes` emits.
+create table if not exists proposal_one_off_transaction_result (
+    proposal_id integer not null primary key
+        references proposal_one_off_transaction (proposal_id) on delete cascade,
+    r           blob    not null check (length(r) = 32),
+    s           blob    not null check (length(s) = 32),
+    y_parity    integer not null check (y_parity in (0, 1)),
+    created_at  integer not null default(unixepoch('now'))
+) STRICT;
+
+-- ===============================
+-- Recovery Operators (§3.4/§3.5/§3.6)
+-- ===============================
+
+-- Encrypted Shamir shares for recovery operators (mirrors the `operator` table).
+create table if not exists recovery_operator (
+    id          integer not null primary key references recovery_operator_identity(id) on delete restrict,
+    share       blob    not null,
+    share_nonce blob    not null,
+    share_salt  blob    not null,
+    created_at  integer not null default(unixepoch('now')),
+    updated_at  integer not null default(unixepoch('now'))
+) STRICT;
+
+create table if not exists recovery_operator_identity (
+    id         integer not null primary key,
+    public_key blob    not null unique,
+    created_at integer not null default(unixepoch('now')),
+    updated_at integer not null default(unixepoch('now'))
+) STRICT;
+
+-- One active wakeup request at a time. A request is pending when cancelled_at IS NULL
+-- and requested_at + 14 days > now. It becomes active (recovery live) after 14 days.
+create table if not exists recovery_wakeup_request (
+    id           integer not null primary key,
+    requested_by integer not null references operator_identity(id) on delete restrict,
+    requested_at integer not null default(unixepoch('now')),
+    cancelled_by integer references operator_identity(id) on delete restrict,
+    cancelled_at integer
+) STRICT;
+
+-- Votes cast by recovery operators; only allowed on replace_operator proposals.
+create table if not exists recovery_proposal_vote (
+    id                   integer not null primary key,
+    proposal_id          integer not null references proposal(id) on delete cascade,
+    recovery_operator_id integer not null references recovery_operator_identity(id) on delete restrict,
+    approve              integer not null check (approve in (0, 1)),
+    signature            blob    not null,
+    voted_at             integer not null default(unixepoch('now')),
+    unique (proposal_id, recovery_operator_id)
+) STRICT;

server/crates/arbiter-server/src/actors/bootstrap.rs

@@ -1,48 +1,56 @@
+use crate::db::{self, DatabasePool, schema};
 use arbiter_proto::{BOOTSTRAP_PATH, home_path};
+
 use diesel::QueryDsl;
 use diesel_async::RunQueryDsl;
 use kameo::{Actor, messages};
-use miette::Diagnostic;
 use rand::{
-    RngExt,
-    distr::{Alphanumeric},
+    distr::{Alphanumeric, SampleString as _},
     make_rng,
     rngs::StdRng,
 };
+use std::path::Path;
+use subtle::ConstantTimeEq as _;
 use thiserror::Error;
 
-use crate::db::{self, DatabasePool, schema};
 const TOKEN_LENGTH: usize = 64;
 
-pub async fn generate_token() -> Result<String, std::io::Error> {
-    let rng: StdRng = make_rng();
+pub async fn generate_token(home: &Path) -> Result<String, std::io::Error> {
+    let mut rng: StdRng = make_rng();
 
-    let token: String = rng.sample_iter(Alphanumeric).take(TOKEN_LENGTH).fold(
-        Default::default(),
-        |mut accum, char| {
-            accum += char.to_string().as_str();
-            accum
-        },
-    );
+    // `Alphanumeric` samples raw `u8` ASCII codes, not `char`s -- `SampleString::sample_string`
+    // is `rand`'s own documented way to turn that into an actual TOKEN_LENGTH-character string
+    // (see the "Passwords" example on `Alphanumeric`'s docs). A prior version of this function
+    // called `.to_string()` on the sampled `u8` directly, which stringifies the numeric byte
+    // value (e.g. `65` instead of `'A'`) rather than the character it represents, silently
+    // producing a variable-length, all-decimal-digit string instead of a real token.
+    let token = Alphanumeric.sample_string(&mut rng, TOKEN_LENGTH);
 
-    tokio::fs::write(home_path()?.join(BOOTSTRAP_PATH), token.as_str()).await?;
+    tokio::fs::write(home.join(BOOTSTRAP_PATH), token.as_str()).await?;
 
     Ok(token)
 }
 
-#[derive(Error, Debug, Diagnostic)]
+/// A token file is only trustworthy if it looks like something `generate_token` could have
+/// produced. Anything else -- empty (a crash between the file's truncate and write), foreign
+/// content, or a trailing newline added by an editor -- must not be adopted as a live
+/// credential: an empty file would make every empty-string token verify, and mismatched
+/// content would silently lock out every operator holding the real, already-printed token.
+#[must_use]
+fn is_valid_token(candidate: &str) -> bool {
+    candidate.len() == TOKEN_LENGTH && candidate.chars().all(|c| c.is_ascii_alphanumeric())
+}
+
+#[derive(Error, Debug)]
 pub enum Error {
     #[error("Database error: {0}")]
-    #[diagnostic(code(arbiter_server::bootstrap::database))]
     Database(#[from] db::PoolError),
 
-    #[error("Database query error: {0}")]
-    #[diagnostic(code(arbiter_server::bootstrap::database_query))]
-    Query(#[from] diesel::result::Error),
-
     #[error("I/O error: {0}")]
-    #[diagnostic(code(arbiter_server::bootstrap::io))]
     Io(#[from] std::io::Error),
+
+    #[error("Database query error: {0}")]
+    Query(#[from] diesel::result::Error),
 }
 
 #[derive(Actor)]
@@ -51,46 +59,107 @@ pub struct Bootstrapper {
 }
 
 impl Bootstrapper {
+    /// Production constructor: resolves the real `~/.arbiter` directory and delegates.
     pub async fn new(db: &DatabasePool) -> Result<Self, Error> {
+        let home = home_path()?;
+        Self::new_in(db, &home).await
+    }
+
+    /// Carries all of `new`'s logic, parameterized on the directory the token file lives in.
+    /// `new` resolves the real home directory and calls this; tests call it directly with a
+    /// throwaway temp directory so they never touch the real `~/.arbiter/bootstrap_token`.
+    pub async fn new_in(db: &DatabasePool, home: &Path) -> Result<Self, Error> {
         let mut conn = db.get().await?;
 
-        let row_count: i64 = schema::useragent_client::table
+        let bootstrapped: bool = schema::arbiter_settings::table
+            .select(schema::arbiter_settings::root_key_id)
+            .first::<Option<i32>>(&mut conn)
+            .await?
+            .is_some();
+
+        if bootstrapped {
+            return Ok(Self { token: None });
+        }
+
+        let any_operator_registered: bool = schema::operator_identity::table
             .count()
-            .get_result(&mut conn)
-            .await?;
+            .get_result::<i64>(&mut conn)
+            .await?
+            > 0;
 
-        drop(conn);
+        if !any_operator_registered {
+            // Nobody has used the current token yet, so there is nothing to preserve across a
+            // restart: generate a fresh one, exactly as on a first run. Reusing an old file
+            // here would let a token survive a database reset, silently reviving trust in
+            // whoever still held it.
+            return Ok(Self {
+                token: Some(generate_token(home).await?),
+            });
+        }
 
-
-        let token = if row_count == 0 {
-            let token = generate_token().await?;
-            Some(token)
-        } else {
-            None
+        // At least one operator has already registered with the current token: every other
+        // declared operator still needs that same token, including across a restart, so an
+        // existing file is reused rather than replaced -- but only if it still looks like a
+        // real token. A truncated, foreign, or corrupted file must not become a live
+        // credential (see `is_valid_token`).
+        let path = home.join(BOOTSTRAP_PATH);
+        let token = match tokio::fs::read_to_string(&path).await {
+            Ok(existing) if is_valid_token(&existing) => existing,
+            Ok(_) => {
+                // Replacing the file invalidates whatever token the already-registered
+                // operators were handed, so it must not happen quietly. The content itself is
+                // a credential and stays out of the log; the path is enough to act on.
+                tracing::warn!(
+                    ?path,
+                    "Bootstrap token file is not a well-formed token; replacing it"
+                );
+                generate_token(home).await?
+            }
+            Err(err) if err.kind() == std::io::ErrorKind::NotFound => generate_token(home).await?,
+            Err(err) => return Err(Error::Io(err)),
         };
 
-        Ok(Self { token })
+        Ok(Self { token: Some(token) })
+    }
+
+    /// Drops the token from memory. Called once the vault is bootstrapped: from then on,
+    /// operators are added through governance rather than through the token.
+    pub(crate) fn forget_token(&mut self) {
+        self.token = None;
+    }
+
+    #[must_use]
+    fn is_correct_token(&self, token: &str) -> bool {
+        self.token.as_ref().is_some_and(|expected| {
+            let expected_bytes = expected.as_bytes();
+            let token_bytes = token.as_bytes();
+
+            let choice = expected_bytes.ct_eq(token_bytes);
+            bool::from(choice)
+        })
     }
 }
 
 #[messages]
 impl Bootstrapper {
+    /// Checks the token without retiring it: every operator in a declared committee
+    /// authenticates with the same token during bootstrap.
     #[message]
-    pub fn is_correct_token(&self, token: String) -> bool {
-        match &self.token {
-            Some(expected) => *expected == token,
-            None => false,
-        }
+    #[must_use]
+    pub fn verify_token(&self, token: String) -> bool {
+        self.is_correct_token(&token)
     }
+}
 
-    #[message]
-    pub fn consume_token(&mut self, token: String) -> bool {
-        if self.is_correct_token(token) {
-            self.token = None;
-            true
-        } else {
-            false
-        }
+impl kameo::prelude::Message<crate::actors::vault::events::Bootstrapped> for Bootstrapper {
+    type Reply = ();
+
+    async fn handle(
+        &mut self,
+        _msg: crate::actors::vault::events::Bootstrapped,
+        _ctx: &mut kameo::prelude::Context<Self, Self::Reply>,
+    ) -> Self::Reply {
+        self.forget_token();
     }
 }
 
@@ -101,3 +170,150 @@ impl Bootstrapper {
         self.token.clone()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use diesel::{ExpressionMethods as _, insert_into, update};
+
+    /// A multi-operator committee registers every member with the same token, so verifying it
+    /// must not consume it. Only a completed bootstrap retires the token.
+    #[tokio::test]
+    async fn token_verifies_repeatedly_until_bootstrap_completes() {
+        let mut bootstrapper = Bootstrapper {
+            token: Some("test-token".to_owned()),
+        };
+
+        assert!(bootstrapper.verify_token("test-token".to_owned()));
+        assert!(bootstrapper.verify_token("test-token".to_owned()));
+        assert!(!bootstrapper.verify_token("wrong-token".to_owned()));
+
+        bootstrapper.forget_token();
+
+        assert!(!bootstrapper.verify_token("test-token".to_owned()));
+        assert!(bootstrapper.get_token().is_none());
+    }
+
+    /// Once the vault is bootstrapped, `Bootstrapper::new_in` must return with no token -- and
+    /// it must do so from `arbiter_settings.root_key_id` alone, taking the early return before
+    /// `home` is ever consulted. Uses `new_in` with a throwaway temp directory (never the
+    /// production `new`, which unconditionally resolves the real home directory before this
+    /// method even runs) so this test cannot touch the real filesystem regardless of outcome.
+    #[tokio::test]
+    async fn new_returns_no_token_once_the_vault_is_bootstrapped() {
+        let db = db::create_test_pool().await;
+        let mut conn = db.get().await.unwrap();
+
+        let root_key_history_id: i32 = insert_into(schema::root_key_history::table)
+            .values(&db::models::NewRootKeyHistory {
+                ciphertext: vec![0u8; 32],
+                tag: vec![0u8; 16],
+                root_key_encryption_nonce: vec![0u8; 24],
+                data_encryption_nonce: vec![0u8; 24],
+                schema_version: 1,
+                salt: vec![0u8; 16],
+            })
+            .returning(schema::root_key_history::id)
+            .get_result(&mut conn)
+            .await
+            .unwrap();
+
+        update(schema::arbiter_settings::table)
+            .set(schema::arbiter_settings::root_key_id.eq(root_key_history_id))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+        drop(conn);
+
+        let home = tempfile::tempdir().unwrap();
+        let bootstrapper = Bootstrapper::new_in(&db, home.path()).await.unwrap();
+
+        assert!(bootstrapper.get_token().is_none());
+    }
+
+    /// The file-reuse path (an operator has already registered, so bootstrap is unfinished)
+    /// must not adopt a corrupted token file as a live credential: it must reject it and
+    /// generate a fresh one instead. This is the Critical from the review, now reachable
+    /// safely because `new_in` takes a throwaway temp directory instead of the real home.
+    #[tokio::test]
+    async fn new_in_rejects_and_replaces_a_corrupted_token_file() {
+        let db = db::create_test_pool().await;
+        let mut conn = db.get().await.unwrap();
+
+        // At least one operator must have registered, or `new_in` would regenerate
+        // unconditionally regardless of the file (Important 2) and never exercise validation.
+        insert_into(schema::operator_identity::table)
+            .values(schema::operator_identity::public_key.eq(vec![0u8; 32]))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+        drop(conn);
+
+        let home = tempfile::tempdir().unwrap();
+        tokio::fs::write(home.path().join(BOOTSTRAP_PATH), "")
+            .await
+            .unwrap();
+
+        let bootstrapper = Bootstrapper::new_in(&db, home.path()).await.unwrap();
+
+        let token = bootstrapper
+            .get_token()
+            .expect("a fresh token must be generated");
+        assert!(is_valid_token(&token));
+
+        // The replacement must also have landed on disk, not just in memory, so a restart
+        // reads back the same (now valid) token rather than the corrupted one again.
+        let on_disk = tokio::fs::read_to_string(home.path().join(BOOTSTRAP_PATH))
+            .await
+            .unwrap();
+        assert_eq!(on_disk, token);
+    }
+
+    /// The second defect the task exists to fix: a restart between the first registration and
+    /// the completed bootstrap must not invalidate the token the other declared operators were
+    /// already given. With an operator registered and a well-formed file on disk, `new_in` has
+    /// to hand back exactly what it read instead of generating a replacement.
+    #[tokio::test]
+    async fn new_in_reuses_a_valid_token_file_across_a_restart() {
+        let db = db::create_test_pool().await;
+        let mut conn = db.get().await.unwrap();
+
+        // Without a registered operator, `new_in` regenerates unconditionally (Important 2 of
+        // the round-2 review) and never reaches the reuse path this test is about.
+        insert_into(schema::operator_identity::table)
+            .values(schema::operator_identity::public_key.eq(vec![0u8; 32]))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+        drop(conn);
+
+        let home = tempfile::tempdir().unwrap();
+        // Stands in for the token a previous run wrote and printed to the console.
+        let handed_out = "Zq7Z2rXaB90kLmNpQwErTyUiOpAsDfGhJkLzXcVbNmQwErTyUiOpAsDfGhJkLzXc";
+        assert!(is_valid_token(handed_out));
+        tokio::fs::write(home.path().join(BOOTSTRAP_PATH), handed_out)
+            .await
+            .unwrap();
+
+        let bootstrapper = Bootstrapper::new_in(&db, home.path()).await.unwrap();
+
+        assert_eq!(bootstrapper.get_token().as_deref(), Some(handed_out));
+    }
+
+    /// An empty file must not be adopted as a live credential: `is_correct_token`'s
+    /// `is_some_and` would enter its closure for `Some(String::new())`, and comparing two empty
+    /// byte slices is true, so an unauthenticated `Some("")` from the wire would otherwise
+    /// verify. Also pins the other corrupted-content shapes `is_valid_token` must reject.
+    #[test]
+    fn is_valid_token_rejects_anything_that_is_not_a_real_token() {
+        assert!(!is_valid_token(""));
+        assert!(!is_valid_token("too-short"));
+        assert!(!is_valid_token(&"a".repeat(TOKEN_LENGTH - 1)));
+        assert!(!is_valid_token(&"a".repeat(TOKEN_LENGTH + 1)));
+        // A trailing newline (e.g. from an editor) must not be silently accepted either.
+        assert!(!is_valid_token(&format!("{}\n", "a".repeat(TOKEN_LENGTH))));
+        assert!(!is_valid_token(&"!".repeat(TOKEN_LENGTH)));
+
+        assert!(is_valid_token(&"a".repeat(TOKEN_LENGTH)));
+    }
+}

server/crates/arbiter-server/src/actors/client/auth/mod.rs

@@ -1,102 +0,0 @@
-use arbiter_proto::proto::client::{
-    AuthChallengeRequest, AuthChallengeSolution, ClientRequest,
-    client_request::Payload as ClientRequestPayload,
-};
-use ed25519_dalek::VerifyingKey;
-use tracing::error;
-
-use crate::actors::client::{
-    ClientConnection,
-    auth::state::{AuthContext, AuthStateMachine},
-    session::ClientSession,
-};
-
-#[derive(thiserror::Error, Debug, Clone, PartialEq, Eq)]
-pub enum Error {
-    #[error("Unexpected message payload")]
-    UnexpectedMessagePayload,
-    #[error("Invalid client public key length")]
-    InvalidClientPubkeyLength,
-    #[error("Invalid client public key encoding")]
-    InvalidAuthPubkeyEncoding,
-    #[error("Database pool unavailable")]
-    DatabasePoolUnavailable,
-    #[error("Database operation failed")]
-    DatabaseOperationFailed,
-    #[error("Public key not registered")]
-    PublicKeyNotRegistered,
-    #[error("Invalid signature length")]
-    InvalidSignatureLength,
-    #[error("Invalid challenge solution")]
-    InvalidChallengeSolution,
-    #[error("Transport error")]
-    Transport,
-}
-
-mod state;
-use state::*;
-
-fn parse_auth_event(payload: ClientRequestPayload) -> Result<AuthEvents, Error> {
-    match payload {
-        ClientRequestPayload::AuthChallengeRequest(AuthChallengeRequest { pubkey }) => {
-            let pubkey_bytes = pubkey.as_array().ok_or(Error::InvalidClientPubkeyLength)?;
-            let pubkey = VerifyingKey::from_bytes(pubkey_bytes)
-                .map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
-            Ok(AuthEvents::AuthRequest(ChallengeRequest {
-                pubkey: pubkey.into(),
-            }))
-        }
-        ClientRequestPayload::AuthChallengeSolution(AuthChallengeSolution { signature }) => {
-            Ok(AuthEvents::ReceivedSolution(ChallengeSolution {
-                solution: signature,
-            }))
-        }
-        _ => Err(Error::UnexpectedMessagePayload) ,
-    }
-}
-
-pub async fn authenticate(props: &mut ClientConnection) -> Result<VerifyingKey, Error> {
-    let mut state = AuthStateMachine::new(AuthContext::new(props));
-
-    loop {
-        let transport = state.context_mut().conn.transport.as_mut();
-        let Some(ClientRequest {
-            payload: Some(payload),
-        }) = transport.recv().await
-        else {
-            return Err(Error::Transport);
-        };
-
-        let event = parse_auth_event(payload)?;
-
-        match state.process_event(event).await {
-            Ok(AuthStates::AuthOk(key)) => return Ok(key.clone()),
-            Err(AuthError::ActionFailed(err)) => {
-                error!(?err, "State machine action failed");
-                return Err(err);
-            }
-            Err(AuthError::GuardFailed(err)) => {
-                error!(?err, "State machine guard failed");
-                return Err(err);
-            }
-            Err(AuthError::InvalidEvent) => {
-                error!("Invalid event for current state");
-                return Err(Error::InvalidChallengeSolution);
-            }
-            Err(AuthError::TransitionsFailed) => {
-                error!("Invalid state transition");
-                return Err(Error::InvalidChallengeSolution);
-            }
-
-            _ => (),
-        }
-    }
-}
-
-pub async fn authenticate_and_create(
-    mut props: ClientConnection,
-) -> Result<ClientSession, Error> {
-    let key = authenticate(&mut props).await?;
-    let session = ClientSession::new(props, key);
-    Ok(session)
-}

server/crates/arbiter-server/src/actors/client/auth/state.rs

@@ -1,136 +0,0 @@
-use arbiter_proto::proto::client::{
-    AuthChallenge, ClientResponse,
-    client_response::Payload as ClientResponsePayload,
-};
-use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl, update};
-use diesel_async::RunQueryDsl;
-use ed25519_dalek::VerifyingKey;
-use tracing::error;
-
-use super::Error;
-use crate::{actors::client::ClientConnection, db::schema};
-
-pub struct ChallengeRequest {
-    pub pubkey: VerifyingKey,
-}
-
-pub struct ChallengeContext {
-    pub challenge: AuthChallenge,
-    pub key: VerifyingKey,
-}
-
-pub struct ChallengeSolution {
-    pub solution: Vec<u8>,
-}
-
-smlang::statemachine!(
-    name: Auth,
-    custom_error: true,
-    transitions: {
-        *Init + AuthRequest(ChallengeRequest) / async prepare_challenge = SentChallenge(ChallengeContext),
-        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) [async verify_solution] / provide_key = AuthOk(VerifyingKey),
-    }
-);
-
-async fn create_nonce(db: &crate::db::DatabasePool, pubkey_bytes: &[u8]) -> Result<i32, Error> {
-    let mut db_conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::DatabasePoolUnavailable
-    })?;
-    db_conn
-        .exclusive_transaction(|conn| {
-            Box::pin(async move {
-                let current_nonce = schema::program_client::table
-                    .filter(schema::program_client::public_key.eq(pubkey_bytes.to_vec()))
-                    .select(schema::program_client::nonce)
-                    .first::<i32>(conn)
-                    .await?;
-
-                update(schema::program_client::table)
-                    .filter(schema::program_client::public_key.eq(pubkey_bytes.to_vec()))
-                    .set(schema::program_client::nonce.eq(current_nonce + 1))
-                    .execute(conn)
-                    .await?;
-
-                Result::<_, diesel::result::Error>::Ok(current_nonce)
-            })
-        })
-        .await
-        .optional()
-        .map_err(|e| {
-            error!(error = ?e, "Database error");
-            Error::DatabaseOperationFailed
-        })?
-        .ok_or_else(|| {
-            error!(?pubkey_bytes, "Public key not found in database");
-            Error::PublicKeyNotRegistered
-        })
-}
-
-pub struct AuthContext<'a> {
-    pub(super) conn: &'a mut ClientConnection,
-}
-
-impl<'a> AuthContext<'a> {
-    pub fn new(conn: &'a mut ClientConnection) -> Self {
-        Self { conn }
-    }
-}
-
-impl AuthStateMachineContext for AuthContext<'_> {
-    type Error = Error;
-
-    async fn verify_solution(
-        &self,
-        ChallengeContext { challenge, key }: &ChallengeContext,
-        ChallengeSolution { solution }: &ChallengeSolution,
-    ) -> Result<bool, Self::Error> {
-        let formatted_challenge =
-            arbiter_proto::format_challenge(challenge.nonce, &challenge.pubkey);
-
-        let signature = solution.as_slice().try_into().map_err(|_| {
-            error!(?solution, "Invalid signature length");
-            Error::InvalidChallengeSolution
-        })?;
-
-        let valid = key.verify_strict(&formatted_challenge, &signature).is_ok();
-
-        Ok(valid)
-    }
-
-    async fn prepare_challenge(
-        &mut self,
-        ChallengeRequest { pubkey }: ChallengeRequest,
-    ) -> Result<ChallengeContext, Self::Error> {
-        let nonce = create_nonce(&self.conn.db, pubkey.as_bytes()).await?;
-
-        let challenge = AuthChallenge {
-            pubkey: pubkey.as_bytes().to_vec(),
-            nonce,
-        };
-
-        self.conn
-            .transport
-            .send(Ok(ClientResponse {
-                payload: Some(ClientResponsePayload::AuthChallenge(challenge.clone())),
-            }))
-            .await
-            .map_err(|e| {
-                error!(?e, "Failed to send auth challenge");
-                Error::Transport
-            })?;
-
-        Ok(ChallengeContext {
-            challenge,
-            key: pubkey,
-        })
-    }
-
-    fn provide_key(
-        &mut self,
-        state_data: &ChallengeContext,
-        _: ChallengeSolution,
-    ) -> Result<VerifyingKey, Self::Error> {
-        Ok(state_data.key)
-    }
-}

server/crates/arbiter-server/src/actors/client/mod.rs

@@ -1,58 +0,0 @@
-use arbiter_proto::{
-    proto::client::{ClientRequest, ClientResponse},
-    transport::Bi,
-};
-use kameo::actor::Spawn;
-use tracing::{error, info};
-
-use crate::{
-    actors::{GlobalActors, client::session::ClientSession},
-    db,
-};
-
-#[derive(Debug, Clone, PartialEq, Eq, thiserror::Error)]
-pub enum ClientError {
-    #[error("Expected message with payload")]
-    MissingRequestPayload,
-    #[error("Unexpected request payload")]
-    UnexpectedRequestPayload,
-    #[error("State machine error")]
-    StateTransitionFailed,
-    #[error("Connection registration failed")]
-    ConnectionRegistrationFailed,
-    #[error(transparent)]
-    Auth(#[from] auth::Error),
-}
-
-pub type Transport = Box<dyn Bi<ClientRequest, Result<ClientResponse, ClientError>> + Send>;
-
-pub struct ClientConnection {
-    pub(crate) db: db::DatabasePool,
-    pub(crate) transport: Transport,
-    pub(crate) actors: GlobalActors,
-}
-
-impl ClientConnection {
-    pub fn new(db: db::DatabasePool, transport: Transport, actors: GlobalActors) -> Self {
-        Self {
-            db,
-            transport,
-            actors,
-        }
-    }
-}
-
-pub mod auth;
-pub mod session;
-
-pub async fn connect_client(props: ClientConnection) {
-    match auth::authenticate_and_create(props).await {
-        Ok(session) => {
-            ClientSession::spawn(session);
-            info!("Client authenticated, session started");
-        }
-        Err(err) => {
-            error!(?err, "Authentication failed, closing connection");
-        }
-    }
-}

server/crates/arbiter-server/src/actors/client/session.rs

@@ -1,98 +0,0 @@
-use arbiter_proto::proto::client::{ClientRequest, ClientResponse};
-use ed25519_dalek::VerifyingKey;
-use kameo::Actor;
-use tokio::select;
-use tracing::{error, info};
-
-use crate::{actors::{
-    GlobalActors, client::{ClientError, ClientConnection}, router::RegisterClient
-}, db};
-
-pub struct ClientSession {
-    props: ClientConnection,
-    key: VerifyingKey,
-}
-
-impl ClientSession {
-    pub(crate) fn new(props: ClientConnection, key: VerifyingKey) -> Self {
-        Self { props, key }
-    }
-
-    pub async fn process_transport_inbound(&mut self, req: ClientRequest) -> Output {
-        let msg = req.payload.ok_or_else(|| {
-            error!(actor = "client", "Received message with no payload");
-            ClientError::MissingRequestPayload
-        })?;
-
-        match msg {
-            _ => Err(ClientError::UnexpectedRequestPayload),
-        }
-    }
-}
-
-type Output = Result<ClientResponse, ClientError>;
-
-impl Actor for ClientSession {
-    type Args = Self;
-
-    type Error = ClientError;
-
-    async fn on_start(
-        args: Self::Args,
-        this: kameo::prelude::ActorRef<Self>,
-    ) -> Result<Self, Self::Error> {
-        args.props
-            .actors
-            .router
-            .ask(RegisterClient { actor: this })
-            .await
-            .map_err(|_| ClientError::ConnectionRegistrationFailed)?;
-        Ok(args)
-    }
-
-    async fn next(
-        &mut self,
-        _actor_ref: kameo::prelude::WeakActorRef<Self>,
-        mailbox_rx: &mut kameo::prelude::MailboxReceiver<Self>,
-    ) -> Option<kameo::mailbox::Signal<Self>> {
-        loop {
-            select! {
-                signal = mailbox_rx.recv() => {
-                    return signal;
-                }
-                msg = self.props.transport.recv() => {
-                    match msg {
-                        Some(request) => {
-                            match self.process_transport_inbound(request).await {
-                                Ok(resp) => {
-                                    if self.props.transport.send(Ok(resp)).await.is_err() {
-                                        error!(actor = "client", reason = "channel closed", "send.failed");
-                                        return Some(kameo::mailbox::Signal::Stop);
-                                    }
-                                }
-                                Err(err) => {
-                                    let _ = self.props.transport.send(Err(err)).await;
-                                    return Some(kameo::mailbox::Signal::Stop);
-                                }
-                            }
-                        }
-                        None => {
-                            info!(actor = "client", "transport.closed");
-                            return Some(kameo::mailbox::Signal::Stop);
-                        }
-                    }
-                }
-            }
-        }
-    }
-}
-
-impl ClientSession {
-    pub fn new_test(db: db::DatabasePool, actors: GlobalActors) -> Self {
-        use arbiter_proto::transport::DummyTransport;
-        let transport: super::Transport = Box::new(DummyTransport::new());
-        let props = ClientConnection::new(db, transport, actors);
-        let key = VerifyingKey::from_bytes(&[0u8; 32]).unwrap();
-        Self { props, key }
-    }
-}

server/crates/arbiter-server/src/actors/evm/mod.rs

@@ -1,138 +1,186 @@
-use alloy::{consensus::TxEip1559, network::TxSigner, primitives::Address, signers::Signature};
-use diesel::{ExpressionMethods, OptionalExtension as _, QueryDsl, SelectableHelper as _, dsl::insert_into};
-use diesel_async::RunQueryDsl;
-use kameo::{Actor, actor::ActorRef, messages};
-use memsafe::MemSafe;
-use rand::{SeedableRng, rng, rngs::StdRng};
-
 use crate::{
-    actors::keyholder::{CreateNew, Decrypt, KeyHolder},
-    db::{self, DatabasePool, models::{self, EvmBasicGrant, SqliteTimestamp}, schema},
+    actors::{
+        proposal_manager::events::ProposalApproved,
+        vault::{CreateNew, Decrypt, Vault},
+    },
+    crypto::integrity,
+    db::{
+        DatabaseError, DatabasePool,
+        models::{self, EvmWalletId, ProposalId},
+        proposal::{ProposalKind, grant_wallet_access, one_off_transaction, persistent_grant},
+        schema,
+    },
     evm::{
-        self, RunKind,
+        self, ListError, RunKind,
         policies::{
-            FullGrant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
-            ether_transfer::EtherTransfer,
-            token_transfers::TokenTransfer,
+            CombinedSettings, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
+            ether_transfer::EtherTransfer, token_transfers::TokenTransfer,
         },
     },
 };
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+
+use alloy::{
+    consensus::TxEip1559, network::TxSignerSync as _, primitives::Address, signers::Signature,
+};
+use diesel::{
+    ExpressionMethods, OptionalExtension as _, QueryDsl, SelectableHelper as _, dsl::insert_into,
+};
+use diesel_async::RunQueryDsl;
+use kameo::{Actor, actor::ActorRef, messages, prelude::Message};
+use rand::{SeedableRng, rng, rngs::StdRng};
+use tracing::error;
 
 pub use crate::evm::safe_signer;
 
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
+#[derive(Debug, thiserror::Error)]
 pub enum SignTransactionError {
     #[error("Wallet not found")]
-    #[diagnostic(code(arbiter::evm::sign::wallet_not_found))]
     WalletNotFound,
 
     #[error("Database error: {0}")]
-    #[diagnostic(code(arbiter::evm::sign::database))]
-    Database(#[from] diesel::result::Error),
+    Database(#[from] DatabaseError),
 
-    #[error("Database pool error: {0}")]
-    #[diagnostic(code(arbiter::evm::sign::pool))]
-    Pool(#[from] db::PoolError),
+    #[error("Vault error: {0}")]
+    Vault(#[from] crate::actors::vault::Error),
 
-    #[error("Keyholder error: {0}")]
-    #[diagnostic(code(arbiter::evm::sign::keyholder))]
-    Keyholder(#[from] crate::actors::keyholder::Error),
-
-    #[error("Keyholder mailbox error")]
-    #[diagnostic(code(arbiter::evm::sign::keyholder_send))]
-    KeyholderSend,
+    #[error("Vault mailbox error")]
+    VaultSend,
 
     #[error("Signing error: {0}")]
-    #[diagnostic(code(arbiter::evm::sign::signing))]
     Signing(#[from] alloy::signers::Error),
 
     #[error("Policy error: {0}")]
-    #[diagnostic(code(arbiter::evm::sign::vet))]
     Vet(#[from] evm::VetError),
 }
 
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
+#[derive(Debug, thiserror::Error)]
 pub enum Error {
-    #[error("Keyholder error: {0}")]
-    #[diagnostic(code(arbiter::evm::keyholder))]
-    Keyholder(#[from] crate::actors::keyholder::Error),
+    #[error("Vault error: {0}")]
+    Vault(#[from] crate::actors::vault::Error),
 
-    #[error("Keyholder mailbox error")]
-    #[diagnostic(code(arbiter::evm::keyholder_send))]
-    KeyholderSend,
+    #[error("Vault mailbox error")]
+    VaultSend,
 
     #[error("Database error: {0}")]
-    #[diagnostic(code(arbiter::evm::database))]
-    Database(#[from] diesel::result::Error),
+    Database(#[from] DatabaseError),
 
-    #[error("Database pool error: {0}")]
-    #[diagnostic(code(arbiter::evm::database_pool))]
-    DatabasePool(#[from] db::PoolError),
+    #[error("Integrity violation: {0}")]
+    Integrity(#[from] integrity::Error),
 
-    #[error("Grant creation error: {0}")]
-    #[diagnostic(code(arbiter::evm::creation))]
-    Creation(#[from] evm::CreationError),
+    #[error("Signing error: {0}")]
+    Sign(#[from] SignTransactionError),
+
+    #[error(
+        "Grant timestamp {0} is outside the i32 range a grant boundary column can store \
+         (Unix seconds, so no later than 2038-01-19T03:14:07Z)"
+    )]
+    InvalidTimestamp(i64),
+
+    #[error("Wallet access {0} is revoked or does not exist")]
+    AccessNotActive(i32),
+}
+
+/// Converts a grant boundary from Unix seconds. `None` in means "unbounded"; a value the
+/// boundary column cannot store is an error, never a silently different window.
+///
+/// The range is `i32`, not `i64`, because that is what actually reaches the database:
+/// `SqliteTimestamp::to_sql` narrows to `i32` (`fixme! #84`), so `3_000_000_000` -- a
+/// `valid_from` in 2065 -- would wrap to 1902 and open the grant immediately instead of in
+/// forty years. Accepting only what round-trips keeps the grant that gets written the grant
+/// that was voted on.
+fn grant_timestamp(secs: Option<i64>) -> Result<Option<chrono::DateTime<chrono::Utc>>, Error> {
+    secs.map(|s| {
+        let storable = i32::try_from(s).map_err(|_| Error::InvalidTimestamp(s))?;
+        chrono::DateTime::from_timestamp(i64::from(storable), 0).ok_or(Error::InvalidTimestamp(s))
+    })
+    .transpose()
+}
+
+/// Refuses an access id that is revoked or absent, so nothing hangs a grant off it.
+async fn ensure_access_active(
+    conn: &mut crate::db::DatabaseConnection,
+    access_id: i32,
+) -> Result<(), Error> {
+    let active: bool = diesel::select(diesel::dsl::exists(
+        schema::evm_wallet_access::table
+            .filter(schema::evm_wallet_access::id.eq(access_id))
+            .filter(schema::evm_wallet_access::revoked_at.is_null()),
+    ))
+    .get_result(conn)
+    .await
+    .map_err(DatabaseError::from)?;
+
+    if active {
+        Ok(())
+    } else {
+        Err(Error::AccessNotActive(access_id))
+    }
 }
 
 #[derive(Actor)]
 pub struct EvmActor {
-    pub keyholder: ActorRef<KeyHolder>,
+    pub vault: ActorRef<Vault>,
     pub db: DatabasePool,
     pub rng: StdRng,
     pub engine: evm::Engine,
 }
 
 impl EvmActor {
-    pub fn new(keyholder: ActorRef<KeyHolder>, db: DatabasePool) -> Self {
+    pub fn new(vault: ActorRef<Vault>, db: DatabasePool) -> Self {
         // is it safe to seed rng from system once?
         // todo: audit
         let rng = StdRng::from_rng(&mut rng());
-        let engine = evm::Engine::new(db.clone());
-        Self { keyholder, db, rng, engine }
+        let engine = evm::Engine::new(db.clone(), vault.clone());
+        Self {
+            vault,
+            db,
+            rng,
+            engine,
+        }
     }
 }
 
 #[messages]
 impl EvmActor {
     #[message]
-    pub async fn generate(&mut self) -> Result<Address, Error> {
+    pub async fn generate(&mut self) -> Result<(i32, Address), Error> {
         let (mut key_cell, address) = safe_signer::generate(&mut self.rng);
 
-        // Move raw key bytes into a Vec<u8> MemSafe for KeyHolder
-        let plaintext = {
-            let reader = key_cell.read().expect("MemSafe read");
-            MemSafe::new(reader.to_vec()).expect("MemSafe allocation")
-        };
+        let plaintext = key_cell.read_inline(|reader| SafeCell::new(reader.to_vec()));
 
         let aead_id: i32 = self
-            .keyholder
+            .vault
             .ask(CreateNew { plaintext })
             .await
-            .map_err(|_| Error::KeyholderSend)?;
+            .map_err(|_| Error::VaultSend)?;
 
-        let mut conn = self.db.get().await?;
-        insert_into(schema::evm_wallet::table)
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
+        let wallet_id = insert_into(schema::evm_wallet::table)
             .values(&models::NewEvmWallet {
                 address: address.as_slice().to_vec(),
                 aead_encrypted_id: aead_id,
             })
-            .execute(&mut conn)
-            .await?;
+            .returning(schema::evm_wallet::id)
+            .get_result(&mut conn)
+            .await
+            .map_err(DatabaseError::from)?;
 
-        Ok(address)
+        Ok((wallet_id, address))
     }
 
     #[message]
-    pub async fn list_wallets(&self) -> Result<Vec<Address>, Error> {
-        let mut conn = self.db.get().await?;
+    pub async fn list_wallets(&self) -> Result<Vec<(EvmWalletId, Address)>, Error> {
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
         let rows: Vec<models::EvmWallet> = schema::evm_wallet::table
             .select(models::EvmWallet::as_select())
             .load(&mut conn)
-            .await?;
+            .await
+            .map_err(DatabaseError::from)?;
 
         Ok(rows
             .into_iter()
-            .map(|w| Address::from_slice(&w.address))
+            .map(|w| (w.id, Address::from_slice(&w.address)))
             .collect())
     }
 }
@@ -140,51 +188,58 @@ impl EvmActor {
 #[messages]
 impl EvmActor {
     #[message]
-    pub async fn useragent_create_grant(
+    pub async fn operator_create_grant(
         &mut self,
-        client_id: i32,
         basic: SharedGrantSettings,
         grant: SpecificGrant,
-    ) -> Result<i32, evm::CreationError> {
+    ) -> Result<i32, Error> {
         match grant {
-            SpecificGrant::EtherTransfer(settings) => {
-                self.engine
-                    .create_grant::<EtherTransfer>(client_id, FullGrant { basic, specific: settings })
-                    .await
-            }
-            SpecificGrant::TokenTransfer(settings) => {
-                self.engine
-                    .create_grant::<TokenTransfer>(client_id, FullGrant { basic, specific: settings })
-                    .await
-            }
+            SpecificGrant::EtherTransfer(settings) => self
+                .engine
+                .create_grant::<EtherTransfer>(CombinedSettings {
+                    shared: basic,
+                    specific: settings,
+                })
+                .await
+                .map_err(Error::from),
+            SpecificGrant::TokenTransfer(settings) => self
+                .engine
+                .create_grant::<TokenTransfer>(CombinedSettings {
+                    shared: basic,
+                    specific: settings,
+                })
+                .await
+                .map_err(Error::from),
         }
     }
 
     #[message]
-    pub async fn useragent_delete_grant(&mut self, grant_id: i32) -> Result<(), Error> {
-        let mut conn = self.db.get().await?;
-        diesel::update(schema::evm_basic_grant::table)
+    pub async fn operator_delete_grant(&mut self, grant_id: i32) -> Result<(), Error> {
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
+
+        let affected = diesel::update(schema::evm_basic_grant::table)
             .filter(schema::evm_basic_grant::id.eq(grant_id))
-            .set(schema::evm_basic_grant::revoked_at.eq(SqliteTimestamp::now()))
+            .set(schema::evm_basic_grant::revoked_at.eq(models::SqliteTimestamp::now()))
             .execute(&mut conn)
-            .await?;
+            .await
+            .map_err(DatabaseError::from)?;
+
+        if affected == 0 {
+            return Err(Error::Database(DatabaseError::from(
+                diesel::result::Error::NotFound,
+            )));
+        }
+
         Ok(())
     }
 
     #[message]
-    pub async fn useragent_list_grants(
-        &mut self,
-        wallet_id: Option<i32>,
-    ) -> Result<Vec<EvmBasicGrant>, Error> {
-        let mut conn = self.db.get().await?;
-        let mut query = schema::evm_basic_grant::table
-            .select(EvmBasicGrant::as_select())
-            .filter(schema::evm_basic_grant::revoked_at.is_null())
-            .into_boxed();
-        if let Some(wid) = wallet_id {
-            query = query.filter(schema::evm_basic_grant::wallet_id.eq(wid));
+    pub async fn operator_list_grants(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
+        match self.engine.list_all_grants().await {
+            Ok(grants) => Ok(grants),
+            Err(ListError::Database(db_err)) => Err(Error::Database(db_err)),
+            Err(ListError::Integrity(integrity_err)) => Err(Error::Integrity(integrity_err)),
         }
-        Ok(query.load(&mut conn).await?)
     }
 
     #[message]
@@ -194,18 +249,30 @@ impl EvmActor {
         wallet_address: Address,
         transaction: TxEip1559,
     ) -> Result<SpecificMeaning, SignTransactionError> {
-        let mut conn = self.db.get().await?;
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
         let wallet = schema::evm_wallet::table
             .select(models::EvmWallet::as_select())
             .filter(schema::evm_wallet::address.eq(wallet_address.as_slice()))
             .first(&mut conn)
             .await
-            .optional()?
+            .optional()
+            .map_err(DatabaseError::from)?
+            .ok_or(SignTransactionError::WalletNotFound)?;
+        let wallet_access = schema::evm_wallet_access::table
+            .select(models::EvmWalletAccess::as_select())
+            .filter(schema::evm_wallet_access::wallet_id.eq(wallet.id))
+            .filter(schema::evm_wallet_access::client_id.eq(client_id))
+            .filter(schema::evm_wallet_access::revoked_at.is_null())
+            .first(&mut conn)
+            .await
+            .optional()
+            .map_err(DatabaseError::from)?
             .ok_or(SignTransactionError::WalletNotFound)?;
         drop(conn);
 
-        let meaning = self.engine
-            .evaluate_transaction(wallet.id, client_id, transaction.clone(), RunKind::Execution)
+        let meaning = self
+            .engine
+            .evaluate_transaction(wallet_access, transaction.clone(), RunKind::Execution)
             .await?;
 
         Ok(meaning)
@@ -218,29 +285,410 @@ impl EvmActor {
         wallet_address: Address,
         mut transaction: TxEip1559,
     ) -> Result<Signature, SignTransactionError> {
-        let mut conn = self.db.get().await?;
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
         let wallet = schema::evm_wallet::table
             .select(models::EvmWallet::as_select())
             .filter(schema::evm_wallet::address.eq(wallet_address.as_slice()))
             .first(&mut conn)
             .await
-            .optional()?
+            .optional()
+            .map_err(DatabaseError::from)?
+            .ok_or(SignTransactionError::WalletNotFound)?;
+        let wallet_access = schema::evm_wallet_access::table
+            .select(models::EvmWalletAccess::as_select())
+            .filter(schema::evm_wallet_access::wallet_id.eq(wallet.id))
+            .filter(schema::evm_wallet_access::client_id.eq(client_id))
+            .filter(schema::evm_wallet_access::revoked_at.is_null())
+            .first(&mut conn)
+            .await
+            .optional()
+            .map_err(DatabaseError::from)?
             .ok_or(SignTransactionError::WalletNotFound)?;
         drop(conn);
 
-        let raw_key: MemSafe<Vec<u8>> = self
-            .keyholder
-            .ask(Decrypt { aead_id: wallet.aead_encrypted_id })
+        let raw_key: SafeCell<Vec<u8>> = self
+            .vault
+            .ask(Decrypt {
+                aead_id: wallet.aead_encrypted_id,
+            })
             .await
-            .map_err(|_| SignTransactionError::KeyholderSend)?;
+            .map_err(|_| SignTransactionError::VaultSend)?;
 
-        let signer = safe_signer::SafeSigner::from_memsafe(raw_key)?;
+        let signer = safe_signer::SafeSigner::from_cell(raw_key)?;
 
         self.engine
-            .evaluate_transaction(wallet.id, client_id, transaction.clone(), RunKind::Execution)
+            .evaluate_transaction(wallet_access, transaction.clone(), RunKind::Execution)
             .await?;
 
-        use alloy::network::TxSignerSync as _;
         Ok(signer.sign_transaction_sync(&mut transaction)?)
     }
 }
+
+impl Message<ProposalApproved> for EvmActor {
+    type Reply = ();
+
+    /// Every subscriber sees every approval and acts only on the kinds it owns.
+    async fn handle(
+        &mut self,
+        msg: ProposalApproved,
+        _ctx: &mut kameo::prelude::Context<Self, Self::Reply>,
+    ) -> Self::Reply {
+        let result = match msg.kind {
+            ProposalKind::GrantWalletAccess(settings) => self.grant_wallet_access(&settings).await,
+            ProposalKind::ApprovePersistentGrant(settings) => {
+                self.create_persistent_grant(*settings).await
+            }
+            ProposalKind::ApproveOneOffTransaction(settings) => {
+                self.sign_one_off_transaction(msg.id, *settings).await
+            }
+            _ => return,
+        };
+
+        if let Err(error) = result {
+            error!(
+                ?error,
+                proposal_id = msg.id.to_raw(),
+                "Failed to execute an approved proposal"
+            );
+        }
+    }
+}
+
+impl EvmActor {
+    async fn grant_wallet_access(
+        &mut self,
+        settings: &grant_wallet_access::Settings,
+    ) -> Result<(), Error> {
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
+
+        // Revives a previously revoked row instead of conflicting on it forever:
+        // `uniq_wallet_access` is a unique index on `(wallet_id, client_id)`. Visibility is
+        // all this restores -- revocation closes the grants that hung off the access, so a
+        // persistent grant needs its own vote again (§3.2). See
+        // `peers::operator::session::handlers::revoke_wallet_access`.
+        insert_into(schema::evm_wallet_access::table)
+            .values((
+                schema::evm_wallet_access::wallet_id.eq(EvmWalletId::from_raw(settings.wallet_id)),
+                schema::evm_wallet_access::client_id.eq(settings.client_id),
+            ))
+            .on_conflict((
+                schema::evm_wallet_access::wallet_id,
+                schema::evm_wallet_access::client_id,
+            ))
+            .do_update()
+            .set(schema::evm_wallet_access::revoked_at.eq(None::<models::SqliteTimestamp>))
+            .execute(&mut conn)
+            .await
+            .map_err(DatabaseError::from)?;
+
+        Ok(())
+    }
+
+    async fn create_persistent_grant(
+        &mut self,
+        grant: persistent_grant::Settings,
+    ) -> Result<(), Error> {
+        use crate::evm::policies::{
+            TransactionRateLimit, VolumeRateLimit, ether_transfer, token_transfers,
+        };
+        use alloy::primitives::U256;
+        use chrono::Duration;
+
+        // A persistent grant is only as good as the visibility it hangs off (§3.2, two
+        // separate votes). The proposal names the access id when it is created and can be
+        // approved much later, so the access may have been revoked in between; a grant
+        // against a revoked access would sit dormant and go live the moment anyone re-grants.
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
+        ensure_access_active(&mut conn, grant.wallet_access_id).await?;
+        drop(conn);
+
+        let volume = |limit: persistent_grant::VolumeLimit| VolumeRateLimit {
+            max_volume: U256::from_be_bytes(limit.max_volume),
+            window: Duration::seconds(limit.window_secs),
+        };
+
+        let basic = SharedGrantSettings {
+            wallet_access_id: grant.wallet_access_id,
+            chain: grant.chain_id,
+            valid_from: grant_timestamp(grant.valid_from_secs)?,
+            valid_until: grant_timestamp(grant.valid_until_secs)?,
+            max_gas_fee_per_gas: grant.max_gas_fee_per_gas.map(U256::from_be_bytes),
+            max_priority_fee_per_gas: grant.max_priority_fee_per_gas.map(U256::from_be_bytes),
+            rate_limit: grant.rate_limit.map(|r| TransactionRateLimit {
+                count: r.count,
+                window: Duration::seconds(r.window_secs),
+            }),
+        };
+
+        let specific = match grant.specific {
+            persistent_grant::Specific::EtherTransfer { targets, limit } => {
+                SpecificGrant::EtherTransfer(ether_transfer::Settings {
+                    target: targets.into_iter().map(Address::from).collect(),
+                    limit: volume(limit),
+                })
+            }
+            persistent_grant::Specific::TokenTransfer {
+                token_contract,
+                receiver,
+                volume_limits,
+            } => SpecificGrant::TokenTransfer(token_transfers::Settings {
+                token_contract: Address::from(token_contract),
+                target: receiver.map(Address::from),
+                volume_limits: volume_limits.into_iter().map(volume).collect(),
+            }),
+        };
+
+        self.operator_create_grant(basic, specific).await?;
+
+        Ok(())
+    }
+
+    async fn sign_one_off_transaction(
+        &mut self,
+        proposal_id: ProposalId,
+        tx: one_off_transaction::Settings,
+    ) -> Result<(), Error> {
+        use alloy::{
+            eips::eip2930::AccessList,
+            primitives::{Bytes, TxKind, U256},
+        };
+
+        let transaction = TxEip1559 {
+            chain_id: tx.chain_id,
+            nonce: tx.nonce,
+            gas_limit: tx.gas_limit,
+            max_fee_per_gas: tx.max_fee_per_gas,
+            max_priority_fee_per_gas: tx.max_priority_fee_per_gas,
+            to: TxKind::Call(Address::from(tx.to)),
+            value: U256::from_be_bytes(tx.value),
+            input: Bytes::from(tx.input),
+            access_list: AccessList::default(),
+        };
+
+        let signature = self
+            .client_sign_transaction(tx.client_id, Address::from(tx.wallet_address), transaction)
+            .await?;
+
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
+        one_off_transaction::store_signature(proposal_id, &signature, &mut conn)
+            .await
+            .map_err(DatabaseError::from)?;
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{Error, EvmActor, ensure_access_active, grant_timestamp};
+    use crate::db::{self, models, schema};
+
+    use diesel::{ExpressionMethods as _, QueryDsl as _, dsl::insert_into};
+    use diesel_async::RunQueryDsl;
+
+    #[test]
+    fn absent_timestamp_stays_absent() {
+        assert!(grant_timestamp(None).unwrap().is_none());
+    }
+
+    #[test]
+    fn in_range_timestamp_is_converted() {
+        let converted = grant_timestamp(Some(1_800_000_000)).unwrap();
+        assert_eq!(converted.unwrap().timestamp(), 1_800_000_000);
+    }
+
+    /// An unrepresentable expiry must not silently become "no expiry": that would widen the
+    /// grant beyond what was voted on.
+    #[test]
+    fn out_of_range_timestamp_is_an_error() {
+        let err = grant_timestamp(Some(i64::MAX)).unwrap_err();
+        assert!(matches!(err, Error::InvalidTimestamp(i64::MAX)));
+    }
+
+    /// A `valid_from` past 2038 is representable as a `DateTime` but not as the `i32` the
+    /// boundary column stores: `3_000_000_000` (2065) wraps to a negative, which reads back as
+    /// 1902 and makes the grant active immediately. Refusing it is the only way the grant
+    /// that lands can match the window that was voted on.
+    #[test]
+    fn a_timestamp_past_2038_is_an_error() {
+        let past_2038 = 3_000_000_000_i64;
+        assert!(
+            chrono::DateTime::from_timestamp(past_2038, 0).is_some(),
+            "the fixture must be a date chrono accepts, or it proves nothing about storage"
+        );
+
+        let err = grant_timestamp(Some(past_2038)).unwrap_err();
+        assert!(
+            matches!(err, Error::InvalidTimestamp(got) if got == past_2038),
+            "expected an out-of-range error, got {err:?}"
+        );
+    }
+
+    /// The last second the boundary column can hold must still be accepted: the range check
+    /// has to stop at what storage can take, not short of it.
+    #[test]
+    fn the_last_storable_timestamp_is_accepted() {
+        let converted = grant_timestamp(Some(i64::from(i32::MAX))).unwrap();
+        assert_eq!(converted.unwrap().timestamp(), i64::from(i32::MAX));
+    }
+
+    /// Seeds a wallet, a client and one access row between them, and returns the access id.
+    async fn seed_access(conn: &mut db::DatabaseConnection) -> i32 {
+        let root_key_id: models::RootKeyHistoryId = insert_into(schema::root_key_history::table)
+            .values(&models::NewRootKeyHistory {
+                ciphertext: vec![0u8; 32],
+                tag: vec![0u8; 16],
+                root_key_encryption_nonce: vec![0u8; 24],
+                data_encryption_nonce: vec![0u8; 24],
+                schema_version: 1,
+                salt: vec![0u8; 16],
+            })
+            .returning(schema::root_key_history::id)
+            .get_result(conn)
+            .await
+            .unwrap();
+
+        let aead_id: i32 = insert_into(schema::aead_encrypted::table)
+            .values(&models::NewAeadEncrypted {
+                ciphertext: vec![0u8; 32],
+                tag: vec![0u8; 16],
+                current_nonce: vec![0u8; 24],
+                schema_version: 1,
+                associated_root_key_id: root_key_id,
+                created_at: chrono::Utc::now().into(),
+            })
+            .returning(schema::aead_encrypted::id)
+            .get_result(conn)
+            .await
+            .unwrap();
+
+        let wallet_id: models::EvmWalletId = insert_into(schema::evm_wallet::table)
+            .values((
+                schema::evm_wallet::address.eq(rand::random::<[u8; 20]>().to_vec()),
+                schema::evm_wallet::aead_encrypted_id.eq(aead_id),
+            ))
+            .returning(schema::evm_wallet::id)
+            .get_result(conn)
+            .await
+            .unwrap();
+
+        let metadata_id: i32 = insert_into(schema::client_metadata::table)
+            .values(schema::client_metadata::name.eq("test"))
+            .returning(schema::client_metadata::id)
+            .get_result(conn)
+            .await
+            .unwrap();
+
+        let client_id: i32 = insert_into(schema::program_client::table)
+            .values((
+                schema::program_client::public_key.eq(rand::random::<[u8; 32]>().to_vec()),
+                schema::program_client::metadata_id.eq(metadata_id),
+            ))
+            .returning(schema::program_client::id)
+            .get_result(conn)
+            .await
+            .unwrap();
+
+        insert_into(schema::evm_wallet_access::table)
+            .values((
+                schema::evm_wallet_access::wallet_id.eq(wallet_id),
+                schema::evm_wallet_access::client_id.eq(client_id),
+            ))
+            .returning(schema::evm_wallet_access::id)
+            .get_result(conn)
+            .await
+            .unwrap()
+    }
+
+    /// Both directions, so a guard that refused everything could not pass: a live access is
+    /// let through, a revoked one is not.
+    #[tokio::test]
+    async fn only_a_live_access_passes_the_grant_guard() {
+        let pool = db::create_test_pool().await;
+        let mut conn = pool.get().await.unwrap();
+
+        let access_id = seed_access(&mut conn).await;
+        ensure_access_active(&mut conn, access_id)
+            .await
+            .expect("a live access must pass");
+
+        diesel::update(schema::evm_wallet_access::table)
+            .filter(schema::evm_wallet_access::id.eq(access_id))
+            .set(schema::evm_wallet_access::revoked_at.eq(models::SqliteTimestamp::now()))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+
+        let err = ensure_access_active(&mut conn, access_id)
+            .await
+            .expect_err("a revoked access must be refused");
+        assert!(
+            matches!(err, Error::AccessNotActive(got) if got == access_id),
+            "expected AccessNotActive, got {err:?}"
+        );
+    }
+
+    /// The guard has to be wired into the executor, not just exist: an approved persistent
+    /// grant whose access was revoked between proposal and approval must not create a grant
+    /// that would go live again the moment anyone re-grants that access (§3.2).
+    #[tokio::test]
+    async fn an_approved_persistent_grant_refuses_a_revoked_access() {
+        use crate::actors::{GlobalActors, vault::Vault};
+        use crate::db::proposal::persistent_grant;
+        use kameo::actor::Spawn as _;
+
+        let pool = db::create_test_pool().await;
+        let mut conn = pool.get().await.unwrap();
+
+        let access_id = seed_access(&mut conn).await;
+        diesel::update(schema::evm_wallet_access::table)
+            .filter(schema::evm_wallet_access::id.eq(access_id))
+            .set(schema::evm_wallet_access::revoked_at.eq(models::SqliteTimestamp::now()))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+        drop(conn);
+
+        let vault = Vault::spawn(
+            Vault::new(pool.clone(), GlobalActors::spawn_message_bus())
+                .await
+                .unwrap(),
+        );
+        let mut evm_actor = EvmActor::new(vault, pool.clone());
+
+        let err = evm_actor
+            .create_persistent_grant(persistent_grant::Settings {
+                wallet_access_id: access_id,
+                chain_id: 1,
+                valid_from_secs: None,
+                valid_until_secs: None,
+                max_gas_fee_per_gas: None,
+                max_priority_fee_per_gas: None,
+                rate_limit: None,
+                specific: persistent_grant::Specific::EtherTransfer {
+                    targets: vec![[0u8; 20]],
+                    limit: persistent_grant::VolumeLimit {
+                        max_volume: [0u8; 32],
+                        window_secs: 3600,
+                    },
+                },
+            })
+            .await
+            .expect_err("a grant against a revoked access must be refused");
+        assert!(
+            matches!(err, Error::AccessNotActive(got) if got == access_id),
+            "expected AccessNotActive, got {err:?}"
+        );
+
+        let grants: i64 = schema::evm_basic_grant::table
+            .filter(schema::evm_basic_grant::wallet_access_id.eq(access_id))
+            .count()
+            .get_result(&mut pool.get().await.unwrap())
+            .await
+            .unwrap();
+        assert_eq!(
+            grants, 0,
+            "no grant row may be written for a revoked access"
+        );
+    }
+}

server/crates/arbiter-server/src/actors/flow_coordinator/client_connect_approval.rs

@@ -0,0 +1,107 @@
+use crate::{
+    actors::flow_coordinator::ApprovalError,
+    peers::{
+        client::ClientProfile,
+        operator::{OperatorSession, session::BeginNewClientApproval},
+    },
+};
+
+use kameo::{
+    Actor, messages,
+    prelude::{ActorId, ActorRef, ActorStopReason, Context, WeakActorRef},
+    reply::ReplySender,
+};
+use std::ops::ControlFlow;
+
+pub struct Args {
+    pub client: ClientProfile,
+    pub operators: Vec<ActorRef<OperatorSession>>,
+    pub reply: ReplySender<Result<bool, ApprovalError>>,
+}
+
+pub struct ClientApprovalController {
+    /// Number of operators that have not yet responded (approval or denial) or died.
+    pending: usize,
+    /// Number of approvals received so far.
+    approved: usize,
+    reply: Option<ReplySender<Result<bool, ApprovalError>>>,
+}
+
+impl ClientApprovalController {
+    fn send_reply(&mut self, result: Result<bool, ApprovalError>) {
+        if let Some(reply) = self.reply.take() {
+            reply.send(result);
+        }
+    }
+}
+
+impl Actor for ClientApprovalController {
+    type Args = Args;
+    type Error = ();
+
+    async fn on_start(
+        Args {
+            client,
+            operators,
+            reply,
+        }: Self::Args,
+        actor_ref: ActorRef<Self>,
+    ) -> Result<Self, Self::Error> {
+        let this = Self {
+            pending: operators.len(),
+            approved: 0,
+            reply: Some(reply),
+        };
+
+        for operator in operators {
+            actor_ref.link(&operator).await;
+
+            let _ = operator
+                .tell(BeginNewClientApproval {
+                    client: client.clone(),
+                    controller: actor_ref.clone(),
+                })
+                .await;
+        }
+
+        Ok(this)
+    }
+
+    async fn on_link_died(
+        &mut self,
+        _: WeakActorRef<Self>,
+        _: ActorId,
+        _: ActorStopReason,
+    ) -> Result<ControlFlow<ActorStopReason>, Self::Error> {
+        // A linked operator died before responding — counts as a non-approval.
+        self.pending = self.pending.saturating_sub(1);
+        if self.pending == 0 {
+            // At least one operator didn't approve: deny.
+            self.send_reply(Ok(false));
+            return Ok(ControlFlow::Break(ActorStopReason::Normal));
+        }
+        Ok(ControlFlow::Continue(()))
+    }
+}
+
+#[messages]
+impl ClientApprovalController {
+    #[message(ctx)]
+    pub fn client_approval_answer(&mut self, approved: bool, ctx: &mut Context<Self, ()>) {
+        if !approved {
+            // Denial wins immediately regardless of other pending responses.
+            self.send_reply(Ok(false));
+            ctx.stop();
+            return;
+        }
+
+        self.approved += 1;
+        self.pending = self.pending.saturating_sub(1);
+
+        if self.pending == 0 {
+            // Every connected operator approved.
+            self.send_reply(Ok(true));
+            ctx.stop();
+        }
+    }
+}

server/crates/arbiter-server/src/actors/flow_coordinator/mod.rs

@@ -0,0 +1,114 @@
+use crate::{
+    actors::{
+        flow_coordinator::client_connect_approval::ClientApprovalController,
+        operator_registry::{GetConnected, OperatorRegistry},
+    },
+    peers::client::{ClientProfile, session::ClientSession},
+};
+
+use kameo::{
+    Actor,
+    actor::{ActorId, ActorRef, Spawn},
+    messages,
+    prelude::{ActorStopReason, Context, WeakActorRef},
+    reply::DelegatedReply,
+};
+use std::{collections::HashMap, ops::ControlFlow};
+use tracing::info;
+
+pub mod client_connect_approval;
+
+pub struct FlowCoordinator {
+    pub clients: HashMap<ActorId, ActorRef<ClientSession>>,
+    operator_registry: ActorRef<OperatorRegistry>,
+}
+
+impl FlowCoordinator {
+    pub fn new(operator_registry: ActorRef<OperatorRegistry>) -> Self {
+        Self {
+            clients: HashMap::default(),
+            operator_registry,
+        }
+    }
+}
+
+impl Actor for FlowCoordinator {
+    type Args = Self;
+
+    type Error = ();
+
+    async fn on_start(args: Self::Args, _: ActorRef<Self>) -> Result<Self, Self::Error> {
+        Ok(args)
+    }
+
+    async fn on_link_died(
+        &mut self,
+        _: WeakActorRef<Self>,
+        id: ActorId,
+        _: ActorStopReason,
+    ) -> Result<ControlFlow<ActorStopReason>, Self::Error> {
+        if self.clients.remove(&id).is_some() {
+            info!(
+                ?id,
+                actor = "FlowCoordinator",
+                event = "client.disconnected"
+            );
+        } else {
+            info!(
+                ?id,
+                actor = "FlowCoordinator",
+                event = "unknown.actor.disconnected"
+            );
+        }
+        Ok(ControlFlow::Continue(()))
+    }
+}
+
+#[derive(Debug, thiserror::Error, Clone, PartialEq, Eq, Hash)]
+pub enum ApprovalError {
+    #[error("No operators connected")]
+    NoOperatorsConnected,
+}
+
+#[messages]
+impl FlowCoordinator {
+    #[message(ctx)]
+    pub async fn register_client(
+        &mut self,
+        actor: ActorRef<ClientSession>,
+        ctx: &mut Context<Self, ()>,
+    ) {
+        info!(id = %actor.id(), actor = "FlowCoordinator", event = "client.connected");
+        ctx.actor_ref().link(&actor).await;
+        self.clients.insert(actor.id(), actor);
+    }
+
+    #[message(ctx)]
+    pub async fn request_client_approval(
+        &mut self,
+        client: ClientProfile,
+        ctx: &mut Context<Self, DelegatedReply<Result<bool, ApprovalError>>>,
+    ) -> DelegatedReply<Result<bool, ApprovalError>> {
+        let (reply, Some(reply_sender)) = ctx.reply_sender() else {
+            unreachable!("Expected `request_client_approval` to have callback channel");
+        };
+
+        let Ok(refs) = self.operator_registry.ask(GetConnected).await else {
+            reply_sender.send(Err(ApprovalError::NoOperatorsConnected));
+            return reply;
+        };
+
+        if refs.is_empty() {
+            reply_sender.send(Err(ApprovalError::NoOperatorsConnected));
+            return reply;
+        }
+
+        ClientApprovalController::spawn(client_connect_approval::Args {
+            client,
+            operators: refs,
+            reply: reply_sender,
+        });
+
+        reply
+    }
+}

server/crates/arbiter-server/src/actors/keyholder/encryption.rs

@@ -1 +0,0 @@
-pub mod v1;

server/crates/arbiter-server/src/actors/keyholder/encryption/v1.rs

@@ -1,237 +0,0 @@
-use std::ops::Deref as _;
-
-use argon2::{Algorithm, Argon2, password_hash::Salt as ArgonSalt};
-use chacha20poly1305::{
-    AeadInPlace, Key, KeyInit as _, XChaCha20Poly1305, XNonce,
-    aead::{AeadMut, Error, Payload},
-};
-use memsafe::MemSafe;
-use rand::{
-    Rng as _, SeedableRng,
-    rngs::{StdRng, SysRng},
-};
-
-pub const ROOT_KEY_TAG: &[u8] = "arbiter/seal/v1".as_bytes();
-pub const TAG: &[u8] = "arbiter/private-key/v1".as_bytes();
-
-pub const NONCE_LENGTH: usize = 24;
-
-#[derive(Default)]
-pub struct Nonce([u8; NONCE_LENGTH]);
-impl Nonce {
-    pub fn increment(&mut self) {
-        for i in (0..self.0.len()).rev() {
-            if self.0[i] == 0xFF {
-                self.0[i] = 0;
-            } else {
-                self.0[i] += 1;
-                break;
-            }
-        }
-    }
-
-    pub fn to_vec(&self) -> Vec<u8> {
-        self.0.to_vec()
-    }
-}
-impl<'a> TryFrom<&'a [u8]> for Nonce {
-    type Error = ();
-
-    fn try_from(value: &'a [u8]) -> Result<Self, Self::Error> {
-        if value.len() != NONCE_LENGTH {
-            return Err(());
-        }
-        let mut nonce = [0u8; NONCE_LENGTH];
-        nonce.copy_from_slice(value);
-        Ok(Self(nonce))
-    }
-}
-
-pub struct KeyCell(pub MemSafe<Key>);
-impl From<MemSafe<Key>> for KeyCell {
-    fn from(value: MemSafe<Key>) -> Self {
-        Self(value)
-    }
-}
-impl TryFrom<MemSafe<Vec<u8>>> for KeyCell {
-    type Error = ();
-
-    fn try_from(mut value: MemSafe<Vec<u8>>) -> Result<Self, Self::Error> {
-        let value = value.read().unwrap();
-        if value.len() != size_of::<Key>() {
-            return Err(());
-        }
-        let mut cell = MemSafe::new(Key::default()).unwrap();
-        {
-            let mut cell_write = cell.write().unwrap();
-            let cell_slice: &mut [u8] = cell_write.as_mut();
-            cell_slice.copy_from_slice(&value);
-        }
-        Ok(Self(cell))
-    }
-}
-
-impl KeyCell {
-    pub fn new_secure_random() -> Self {
-        let mut key = MemSafe::new(Key::default()).unwrap();
-        {
-            let mut key_buffer = key.write().unwrap();
-            let key_buffer: &mut [u8] = key_buffer.as_mut();
-
-            let mut rng = StdRng::try_from_rng(&mut SysRng).unwrap();
-            rng.fill_bytes(key_buffer);
-        }
-
-        key.into()
-    }
-
-    pub fn encrypt_in_place(
-        &mut self,
-        nonce: &Nonce,
-        associated_data: &[u8],
-        mut buffer: impl AsMut<Vec<u8>>,
-    ) -> Result<(), Error> {
-        let key_reader = self.0.read().unwrap();
-        let key_ref = key_reader.deref();
-        let cipher = XChaCha20Poly1305::new(key_ref);
-        let nonce = XNonce::from_slice(nonce.0.as_ref());
-        let buffer = buffer.as_mut();
-        cipher.encrypt_in_place(nonce, associated_data, buffer)
-    }
-    pub fn decrypt_in_place(
-        &mut self,
-        nonce: &Nonce,
-        associated_data: &[u8],
-        buffer: &mut MemSafe<Vec<u8>>,
-    ) -> Result<(), Error> {
-        let key_reader = self.0.read().unwrap();
-        let key_ref = key_reader.deref();
-        let cipher = XChaCha20Poly1305::new(key_ref);
-        let nonce = XNonce::from_slice(nonce.0.as_ref());
-        let mut buffer = buffer.write().unwrap();
-        let buffer: &mut Vec<u8> = buffer.as_mut();
-        cipher.decrypt_in_place(nonce, associated_data, buffer)
-    }
-
-    pub fn encrypt(
-        &mut self,
-        nonce: &Nonce,
-        associated_data: &[u8],
-        plaintext: impl AsRef<[u8]>,
-    ) -> Result<Vec<u8>, Error> {
-        let key_reader = self.0.read().unwrap();
-        let key_ref = key_reader.deref();
-        let mut cipher = XChaCha20Poly1305::new(key_ref);
-        let nonce = XNonce::from_slice(nonce.0.as_ref());
-
-        let ciphertext = cipher.encrypt(
-            nonce,
-            Payload {
-                msg: plaintext.as_ref(),
-                aad: associated_data,
-            },
-        )?;
-        Ok(ciphertext)
-    }
-}
-
-pub type Salt = [u8; ArgonSalt::RECOMMENDED_LENGTH];
-
-pub fn generate_salt() -> Salt {
-    let mut salt = Salt::default();
-    let mut rng = StdRng::try_from_rng(&mut SysRng).unwrap();
-    rng.fill_bytes(&mut salt);
-    salt
-}
-
-/// User password might be of different length, have not enough entropy, etc...
-/// Derive a fixed-length key from the password using Argon2id, which is designed for password hashing and key derivation.
-pub fn derive_seal_key(mut password: MemSafe<Vec<u8>>, salt: &Salt) -> KeyCell {
-    let params = argon2::Params::new(262_144, 3, 4, None).unwrap();
-    let hasher = Argon2::new(Algorithm::Argon2id, argon2::Version::V0x13, params);
-    let mut key = MemSafe::new(Key::default()).unwrap();
-    {
-        let password_source = password.read().unwrap();
-        let mut key_buffer = key.write().unwrap();
-        let key_buffer: &mut [u8] = key_buffer.as_mut();
-
-        hasher
-            .hash_password_into(password_source.deref(), salt, key_buffer)
-            .unwrap();
-    }
-
-    key.into()
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use memsafe::MemSafe;
-
-    #[test]
-    pub fn derive_seal_key_deterministic() {
-        static PASSWORD: &[u8] = b"password";
-        let password = MemSafe::new(PASSWORD.to_vec()).unwrap();
-        let password2 = MemSafe::new(PASSWORD.to_vec()).unwrap();
-        let salt = generate_salt();
-
-        let mut key1 = derive_seal_key(password, &salt);
-        let mut key2 = derive_seal_key(password2, &salt);
-
-        let key1_reader = key1.0.read().unwrap();
-        let key2_reader = key2.0.read().unwrap();
-
-        assert_eq!(key1_reader.deref(), key2_reader.deref());
-    }
-
-    #[test]
-    pub fn successful_derive() {
-        static PASSWORD: &[u8] = b"password";
-        let password = MemSafe::new(PASSWORD.to_vec()).unwrap();
-        let salt = generate_salt();
-
-        let mut key = derive_seal_key(password, &salt);
-        let key_reader = key.0.read().unwrap();
-        let key_ref = key_reader.deref();
-
-        assert_ne!(key_ref.as_slice(), &[0u8; 32][..]);
-    }
-
-    #[test]
-    pub fn encrypt_decrypt() {
-        static PASSWORD: &[u8] = b"password";
-        let password = MemSafe::new(PASSWORD.to_vec()).unwrap();
-        let salt = generate_salt();
-
-        let mut key = derive_seal_key(password, &salt);
-        let nonce = Nonce(*b"unique nonce 123 1231233"); // 24 bytes for XChaCha20Poly1305
-        let associated_data = b"associated data";
-        let mut buffer = b"secret data".to_vec();
-
-        key.encrypt_in_place(&nonce, associated_data, &mut buffer)
-            .unwrap();
-        assert_ne!(buffer, b"secret data");
-
-        let mut buffer = MemSafe::new(buffer).unwrap();
-
-        key.decrypt_in_place(&nonce, associated_data, &mut buffer)
-            .unwrap();
-
-        let buffer = buffer.read().unwrap();
-        assert_eq!(*buffer, b"secret data");
-    }
-
-    #[test]
-    // We should fuzz this
-    pub fn test_nonce_increment() {
-        let mut nonce = Nonce([0u8; NONCE_LENGTH]);
-        nonce.increment();
-
-        assert_eq!(
-            nonce.0,
-            [
-                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
-            ]
-        );
-    }
-}

server/crates/arbiter-server/src/actors/keyholder/mod.rs

@@ -1,408 +0,0 @@
-use chrono::Utc;
-use diesel::{
-    ExpressionMethods as _, OptionalExtension, QueryDsl, SelectableHelper,
-    dsl::{insert_into, update},
-};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::{Actor, Reply, messages};
-use memsafe::MemSafe;
-use strum::{EnumDiscriminants, IntoDiscriminant};
-use tracing::{error, info};
-
-use crate::db::{
-    self,
-    models::{self, RootKeyHistory},
-    schema::{self},
-};
-use encryption::v1::{self, KeyCell, Nonce};
-
-pub mod encryption;
-
-#[derive(Default, EnumDiscriminants)]
-#[strum_discriminants(derive(Reply), vis(pub))]
-enum State {
-    #[default]
-    Unbootstrapped,
-    Sealed {
-        root_key_history_id: i32,
-    },
-    Unsealed {
-        root_key_history_id: i32,
-        root_key: KeyCell,
-    },
-}
-
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
-pub enum Error {
-    #[error("Keyholder is already bootstrapped")]
-    #[diagnostic(code(arbiter::keyholder::already_bootstrapped))]
-    AlreadyBootstrapped,
-    #[error("Keyholder is not bootstrapped")]
-    #[diagnostic(code(arbiter::keyholder::not_bootstrapped))]
-    NotBootstrapped,
-    #[error("Invalid key provided")]
-    #[diagnostic(code(arbiter::keyholder::invalid_key))]
-    InvalidKey,
-
-    #[error("Requested aead entry not found")]
-    #[diagnostic(code(arbiter::keyholder::aead_not_found))]
-    NotFound,
-
-    #[error("Encryption error: {0}")]
-    #[diagnostic(code(arbiter::keyholder::encryption_error))]
-    Encryption(#[from] chacha20poly1305::aead::Error),
-
-    #[error("Database error: {0}")]
-    #[diagnostic(code(arbiter::keyholder::database_error))]
-    DatabaseConnection(#[from] db::PoolError),
-
-    #[error("Database transaction error: {0}")]
-    #[diagnostic(code(arbiter::keyholder::database_transaction_error))]
-    DatabaseTransaction(#[from] diesel::result::Error),
-
-    #[error("Broken database")]
-    #[diagnostic(code(arbiter::keyholder::broken_database))]
-    BrokenDatabase,
-}
-
-/// Manages vault root key and tracks current state of the vault (bootstrapped/unbootstrapped, sealed/unsealed).
-/// Provides API for encrypting and decrypting data using the vault root key.
-/// Abstraction over database to make sure nonces are never reused and encryption keys are never exposed in plaintext outside of this actor.
-#[derive(Actor)]
-pub struct KeyHolder {
-    db: db::DatabasePool,
-    state: State,
-}
-
-#[messages]
-impl KeyHolder {
-    pub async fn new(db: db::DatabasePool) -> Result<Self, Error> {
-        let state = {
-            let mut conn = db.get().await?;
-
-            let (root_key_history,) = schema::arbiter_settings::table
-                .left_join(schema::root_key_history::table)
-                .select((Option::<RootKeyHistory>::as_select(),))
-                .get_result::<(Option<RootKeyHistory>,)>(&mut conn)
-                .await?;
-
-            match root_key_history {
-                Some(root_key_history) => State::Sealed {
-                    root_key_history_id: root_key_history.id,
-                },
-                None => State::Unbootstrapped,
-            }
-        };
-
-        Ok(Self { db, state })
-    }
-
-    // Exclusive transaction to avoid race condtions if multiple keyholders write
-    // additional layer of protection against nonce-reuse
-    async fn get_new_nonce(pool: &db::DatabasePool, root_key_id: i32) -> Result<Nonce, Error> {
-        let mut conn = pool.get().await?;
-
-        let nonce = conn
-            .exclusive_transaction(|conn| {
-                Box::pin(async move {
-                    let current_nonce: Vec<u8> = schema::root_key_history::table
-                        .filter(schema::root_key_history::id.eq(root_key_id))
-                        .select(schema::root_key_history::data_encryption_nonce)
-                        .first(conn)
-                        .await?;
-
-                    let mut nonce =
-                        v1::Nonce::try_from(current_nonce.as_slice()).map_err(|_| {
-                            error!(
-                                "Broken database: invalid nonce for root key history id={}",
-                                root_key_id
-                            );
-                            Error::BrokenDatabase
-                        })?;
-                    nonce.increment();
-
-                    update(schema::root_key_history::table)
-                        .filter(schema::root_key_history::id.eq(root_key_id))
-                        .set(schema::root_key_history::data_encryption_nonce.eq(nonce.to_vec()))
-                        .execute(conn)
-                        .await?;
-
-                    Result::<_, Error>::Ok(nonce)
-                })
-            })
-            .await?;
-
-        Ok(nonce)
-    }
-
-    #[message]
-    pub async fn bootstrap(&mut self, seal_key_raw: MemSafe<Vec<u8>>) -> Result<(), Error> {
-        if !matches!(self.state, State::Unbootstrapped) {
-            return Err(Error::AlreadyBootstrapped);
-        }
-        let salt = v1::generate_salt();
-        let mut seal_key = v1::derive_seal_key(seal_key_raw, &salt);
-        let mut root_key = KeyCell::new_secure_random();
-
-        // Zero nonces are fine because they are one-time
-        let root_key_nonce = v1::Nonce::default();
-        let data_encryption_nonce = v1::Nonce::default();
-
-        let root_key_ciphertext: Vec<u8> = {
-            let root_key_reader = root_key.0.read().unwrap();
-            let root_key_reader = root_key_reader.as_slice();
-            seal_key
-                .encrypt(&root_key_nonce, v1::ROOT_KEY_TAG, root_key_reader)
-                .map_err(|err| {
-                    error!(?err, "Fatal bootstrap error");
-                    Error::Encryption(err)
-                })?
-        };
-
-        let mut conn = self.db.get().await?;
-
-        let data_encryption_nonce_bytes = data_encryption_nonce.to_vec();
-        let root_key_history_id = conn
-            .transaction(|conn| {
-                Box::pin(async move {
-                    let root_key_history_id: i32 = insert_into(schema::root_key_history::table)
-                        .values(&models::NewRootKeyHistory {
-                            ciphertext: root_key_ciphertext,
-                            tag: v1::ROOT_KEY_TAG.to_vec(),
-                            root_key_encryption_nonce: root_key_nonce.to_vec(),
-                            data_encryption_nonce: data_encryption_nonce_bytes,
-                            schema_version: 1,
-                            salt: salt.to_vec(),
-                        })
-                        .returning(schema::root_key_history::id)
-                        .get_result(conn)
-                        .await?;
-
-                    update(schema::arbiter_settings::table)
-                        .set(schema::arbiter_settings::root_key_id.eq(root_key_history_id))
-                        .execute(conn)
-                        .await?;
-
-                    Result::<_, diesel::result::Error>::Ok(root_key_history_id)
-                })
-            })
-            .await?;
-
-        self.state = State::Unsealed {
-            root_key,
-            root_key_history_id,
-        };
-
-        info!("Keyholder bootstrapped successfully");
-
-        Ok(())
-    }
-
-    #[message]
-    pub async fn try_unseal(&mut self, seal_key_raw: MemSafe<Vec<u8>>) -> Result<(), Error> {
-        let State::Sealed {
-            root_key_history_id,
-        } = &self.state
-        else {
-            return Err(Error::NotBootstrapped);
-        };
-
-        // We don't want to hold connection while doing expensive KDF work
-        let current_key = {
-            let mut conn = self.db.get().await?;
-            schema::root_key_history::table
-                .filter(schema::root_key_history::id.eq(*root_key_history_id))
-                .select(schema::root_key_history::data_encryption_nonce)
-                .select(RootKeyHistory::as_select())
-                .first(&mut conn)
-                .await?
-        };
-
-        let salt = &current_key.salt;
-        let salt = v1::Salt::try_from(salt.as_slice()).map_err(|_| {
-            error!("Broken database: invalid salt for root key");
-            Error::BrokenDatabase
-        })?;
-        let mut seal_key = v1::derive_seal_key(seal_key_raw, &salt);
-
-        let mut root_key = MemSafe::new(current_key.ciphertext.clone()).unwrap();
-
-        let nonce = v1::Nonce::try_from(current_key.root_key_encryption_nonce.as_slice()).map_err(
-            |_| {
-                error!("Broken database: invalid nonce for root key");
-                Error::BrokenDatabase
-            },
-        )?;
-
-        seal_key
-            .decrypt_in_place(&nonce, v1::ROOT_KEY_TAG, &mut root_key)
-            .map_err(|err| {
-                error!(?err, "Failed to unseal root key: invalid seal key");
-                Error::InvalidKey
-            })?;
-
-        self.state = State::Unsealed {
-            root_key_history_id: current_key.id,
-            root_key: v1::KeyCell::try_from(root_key).map_err(|err| {
-                error!(?err, "Broken database: invalid encryption key size");
-                Error::BrokenDatabase
-            })?,
-        };
-
-        info!("Keyholder unsealed successfully");
-
-        Ok(())
-    }
-
-    // Decrypts the `aead_encrypted` entry with the given ID and returns the plaintext
-    #[message]
-    pub async fn decrypt(&mut self, aead_id: i32) -> Result<MemSafe<Vec<u8>>, Error> {
-        let State::Unsealed { root_key, .. } = &mut self.state else {
-            return Err(Error::NotBootstrapped);
-        };
-
-        let row: models::AeadEncrypted = {
-            let mut conn = self.db.get().await?;
-            schema::aead_encrypted::table
-                .select(models::AeadEncrypted::as_select())
-                .filter(schema::aead_encrypted::id.eq(aead_id))
-                .first(&mut conn)
-                .await
-                .optional()?
-                .ok_or(Error::NotFound)?
-        };
-
-        let nonce = v1::Nonce::try_from(row.current_nonce.as_slice()).map_err(|_| {
-            error!(
-                "Broken database: invalid nonce for aead_encrypted id={}",
-                aead_id
-            );
-            Error::BrokenDatabase
-        })?;
-        let mut output = MemSafe::new(row.ciphertext).unwrap();
-        root_key.decrypt_in_place(&nonce, v1::TAG, &mut output)?;
-        Ok(output)
-    }
-
-    // Creates new `aead_encrypted` entry in the database and returns it's ID
-    #[message]
-    pub async fn create_new(&mut self, mut plaintext: MemSafe<Vec<u8>>) -> Result<i32, Error> {
-        let State::Unsealed {
-            root_key,
-            root_key_history_id,
-        } = &mut self.state
-        else {
-            return Err(Error::NotBootstrapped);
-        };
-
-        // Order matters here - `get_new_nonce` acquires connection, so we need to call it before next acquire
-        // Borrow checker note: &mut borrow a few lines above is disjoint from this field
-        let nonce = Self::get_new_nonce(&self.db, *root_key_history_id).await?;
-
-        let mut ciphertext_buffer = plaintext.write().unwrap();
-        let ciphertext_buffer: &mut Vec<u8> = ciphertext_buffer.as_mut();
-        root_key.encrypt_in_place(&nonce, v1::TAG, &mut *ciphertext_buffer)?;
-
-        let ciphertext = std::mem::take(ciphertext_buffer);
-
-        let mut conn = self.db.get().await?;
-        let aead_id: i32 = insert_into(schema::aead_encrypted::table)
-            .values(&models::NewAeadEncrypted {
-                ciphertext,
-                tag: v1::TAG.to_vec(),
-                current_nonce: nonce.to_vec(),
-                schema_version: 1,
-                associated_root_key_id: *root_key_history_id,
-                created_at: Utc::now().into()
-            })
-            .returning(schema::aead_encrypted::id)
-            .get_result(&mut conn)
-            .await?;
-
-        Ok(aead_id)
-    }
-
-    #[message]
-    pub fn get_state(&self) -> StateDiscriminants {
-        self.state.discriminant()
-    }
-
-    #[message]
-    pub fn seal(&mut self) -> Result<(), Error> {
-        let State::Unsealed {
-            root_key_history_id,
-            ..
-        } = &self.state
-        else {
-            return Err(Error::NotBootstrapped);
-        };
-        self.state = State::Sealed {
-            root_key_history_id: *root_key_history_id,
-        };
-        Ok(())
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use diesel::SelectableHelper;
-    
-    use diesel_async::RunQueryDsl;
-    use memsafe::MemSafe;
-
-    use crate::db::{self};
-
-    use super::*;
-
-    async fn bootstrapped_actor(db: &db::DatabasePool) -> KeyHolder {
-        let mut actor = KeyHolder::new(db.clone()).await.unwrap();
-        let seal_key = MemSafe::new(b"test-seal-key".to_vec()).unwrap();
-        actor.bootstrap(seal_key).await.unwrap();
-        actor
-    }
-
-    #[tokio::test]
-    #[test_log::test]
-    async fn nonce_monotonic_even_when_nonce_allocation_interleaves() {
-        let db = db::create_test_pool().await;
-        let mut actor = bootstrapped_actor(&db).await;
-        let root_key_history_id = match actor.state {
-            State::Unsealed {
-                root_key_history_id,
-                ..
-            } => root_key_history_id,
-            _ => panic!("expected unsealed state"),
-        };
-
-        let n1 = KeyHolder::get_new_nonce(&db, root_key_history_id)
-            .await
-            .unwrap();
-        let n2 = KeyHolder::get_new_nonce(&db, root_key_history_id)
-            .await
-            .unwrap();
-        assert!(n2.to_vec() > n1.to_vec(), "nonce must increase");
-
-        let mut conn = db.get().await.unwrap();
-        let root_row: models::RootKeyHistory = schema::root_key_history::table
-            .select(models::RootKeyHistory::as_select())
-            .first(&mut conn)
-            .await
-            .unwrap();
-        assert_eq!(root_row.data_encryption_nonce, n2.to_vec());
-
-        let id = actor
-            .create_new(MemSafe::new(b"post-interleave".to_vec()).unwrap())
-            .await
-            .unwrap();
-        let row: models::AeadEncrypted = schema::aead_encrypted::table
-            .filter(schema::aead_encrypted::id.eq(id))
-            .select(models::AeadEncrypted::as_select())
-            .first(&mut conn)
-            .await
-            .unwrap();
-        assert!(
-            row.current_nonce > n2.to_vec(),
-            "next write must advance nonce"
-        );
-    }
-}

server/crates/arbiter-server/src/actors/mod.rs

@@ -1,47 +1,123 @@
-use kameo::actor::{ActorRef, Spawn};
-use miette::Diagnostic;
-use thiserror::Error;
-
 use crate::{
-    actors::{bootstrap::Bootstrapper, evm::EvmActor, keyholder::KeyHolder, router::MessageRouter},
+    actors::{
+        bootstrap::Bootstrapper,
+        evm::EvmActor,
+        flow_coordinator::FlowCoordinator,
+        operator_registry::OperatorRegistry,
+        proposal_manager::{ProposalManager, events::ProposalApproved},
+        vault::{Vault, events},
+        vault_coordinator::VaultCoordinator,
+    },
     db,
 };
 
-pub mod bootstrap;
-pub mod client;
-mod evm;
-pub mod keyholder;
-pub mod router;
-pub mod user_agent;
+use kameo::actor::{ActorRef, Spawn};
+use kameo_actors::{
+    DeliveryStrategy,
+    message_bus::{MessageBus, Register},
+};
+use thiserror::Error;
+use tracing::error;
 
-#[derive(Error, Debug, Diagnostic)]
+pub mod bootstrap;
+pub mod evm;
+pub mod flow_coordinator;
+pub mod operator_registry;
+pub mod proposal_manager;
+pub mod vault;
+pub mod vault_coordinator;
+
+#[derive(Error, Debug)]
 pub enum SpawnError {
     #[error("Failed to spawn Bootstrapper actor")]
-    #[diagnostic(code(SpawnError::Bootstrapper))]
     Bootstrapper(#[from] bootstrap::Error),
 
-    #[error("Failed to spawn KeyHolder actor")]
-    #[diagnostic(code(SpawnError::KeyHolder))]
-    KeyHolder(#[from] keyholder::Error),
+    #[error("Failed to spawn Vault actor")]
+    Vault(#[from] vault::Error),
 }
 
 /// Long-lived actors that are shared across all connections and handle global state and operations
 #[derive(Clone)]
 pub struct GlobalActors {
-    pub key_holder: ActorRef<KeyHolder>,
+    pub vault: ActorRef<Vault>,
     pub bootstrapper: ActorRef<Bootstrapper>,
-    pub router: ActorRef<MessageRouter>,
+    pub vault_coordinator: ActorRef<VaultCoordinator>,
+    pub flow_coordinator: ActorRef<FlowCoordinator>,
+    pub operator_registry: ActorRef<OperatorRegistry>,
     pub evm: ActorRef<EvmActor>,
+    pub proposal_manager: ActorRef<ProposalManager>,
+    pub events: ActorRef<MessageBus>,
 }
 
 impl GlobalActors {
+    pub fn spawn_message_bus() -> ActorRef<MessageBus> {
+        MessageBus::spawn(MessageBus::new(DeliveryStrategy::Guaranteed))
+    }
+
     pub async fn spawn(db: db::DatabasePool) -> Result<Self, SpawnError> {
-        let key_holder = KeyHolder::spawn(KeyHolder::new(db.clone()).await?);
+        let bootstrapper = Bootstrapper::new(&db).await?;
+        Self::spawn_with_bootstrapper(db, bootstrapper).await
+    }
+
+    /// Test-facing: threads an explicit directory through to `Bootstrapper` instead of letting
+    /// it resolve the real home directory, so a test spawning a full `GlobalActors` can never
+    /// reach (let alone write to) the real `~/.arbiter/bootstrap_token`. Mirrors `spawn`
+    /// exactly, aside from where the token file lives.
+    pub async fn spawn_in(
+        db: db::DatabasePool,
+        home: &std::path::Path,
+    ) -> Result<Self, SpawnError> {
+        let bootstrapper = Bootstrapper::new_in(&db, home).await?;
+        Self::spawn_with_bootstrapper(db, bootstrapper).await
+    }
+
+    async fn spawn_with_bootstrapper(
+        db: db::DatabasePool,
+        bootstrapper: Bootstrapper,
+    ) -> Result<Self, SpawnError> {
+        let message_bus = Self::spawn_message_bus();
+        let key_holder = Vault::spawn(Vault::new(db.clone(), message_bus.clone()).await?);
+        let operator_registry = OperatorRegistry::spawn(OperatorRegistry::default());
+        let evm = EvmActor::spawn(EvmActor::new(key_holder.clone(), db.clone()));
+        let vault_coordinator = VaultCoordinator::spawn(VaultCoordinator::new(
+            db.clone(),
+            key_holder.clone(),
+        ));
+        let bootstrapper = Bootstrapper::spawn(bootstrapper);
+        // Approved proposals are executed by whoever owns the kind, not by ProposalManager.
+        for recipient in [
+            evm.clone().recipient::<ProposalApproved>(),
+            vault_coordinator.clone().recipient::<ProposalApproved>(),
+            key_holder.clone().recipient::<ProposalApproved>(),
+        ] {
+            let _ = message_bus.tell(Register(recipient)).await;
+        }
+        // The token guards bootstrap only: once the vault reports success, it must be retired.
+        // A dropped registration would leave the token valid forever with nothing else to
+        // notice, so a failure here is logged rather than silently discarded.
+        if let Err(err) = message_bus
+            .tell(Register(
+                bootstrapper.clone().recipient::<events::Bootstrapped>(),
+            ))
+            .await
+        {
+            error!(
+                ?err,
+                "Failed to register Bootstrapper for the Bootstrapped event"
+            );
+        }
+
         Ok(Self {
-            bootstrapper: Bootstrapper::spawn(Bootstrapper::new(&db).await?),
-            evm: EvmActor::spawn(EvmActor::new(key_holder.clone(), db)),
-            key_holder,
-            router: MessageRouter::spawn(MessageRouter::default()),
+            bootstrapper,
+            proposal_manager: ProposalManager::spawn(ProposalManager::new(db, message_bus.clone())),
+            vault: key_holder,
+            vault_coordinator,
+            flow_coordinator: FlowCoordinator::spawn(FlowCoordinator::new(
+                operator_registry.clone(),
+            )),
+            operator_registry,
+            events: message_bus,
+            evm,
         })
     }
 }

server/crates/arbiter-server/src/actors/operator_registry.rs

@@ -0,0 +1,61 @@
+use crate::peers::operator::OperatorSession;
+
+use kameo::{
+    Actor,
+    actor::{ActorId, ActorRef},
+    error::Infallible,
+    messages,
+    prelude::{ActorStopReason, Context, WeakActorRef},
+};
+use std::{collections::HashMap, ops::ControlFlow};
+use tracing::info;
+
+#[derive(Default)]
+pub struct OperatorRegistry {
+    connected: HashMap<ActorId, ActorRef<OperatorSession>>,
+}
+
+impl Actor for OperatorRegistry {
+    type Args = Self;
+
+    type Error = Infallible;
+
+    async fn on_start(args: Self::Args, _: ActorRef<Self>) -> Result<Self, Self::Error> {
+        Ok(args)
+    }
+
+    async fn on_link_died(
+        &mut self,
+        _: WeakActorRef<Self>,
+        id: ActorId,
+        _: ActorStopReason,
+    ) -> Result<ControlFlow<ActorStopReason>, Self::Error> {
+        if self.connected.remove(&id).is_some() {
+            info!(
+                ?id,
+                actor = "OperatorRegistry",
+                event = "operator.disconnected"
+            );
+        }
+        Ok(ControlFlow::Continue(()))
+    }
+}
+
+#[messages]
+impl OperatorRegistry {
+    #[message(ctx)]
+    pub async fn connect_operator(
+        &mut self,
+        actor: ActorRef<OperatorSession>,
+        ctx: &mut Context<Self, ()>,
+    ) {
+        info!(id = %actor.id(), actor = "OperatorRegistry", event = "operator.connected");
+        ctx.actor_ref().link(&actor).await;
+        self.connected.insert(actor.id(), actor);
+    }
+
+    #[message]
+    pub fn get_connected(&self) -> Vec<ActorRef<OperatorSession>> {
+        self.connected.values().cloned().collect()
+    }
+}

server/crates/arbiter-server/src/actors/proposal_manager.rs

@@ -0,0 +1,355 @@
+use crate::{
+    actors::proposal_manager::{
+        events::ProposalApproved,
+        store::{DieselProposalStore, ProposalStore, Tally},
+    },
+    crypto::governance,
+    db::{
+        self,
+        models::{
+            NewProposalVote, NewRecoveryProposalVote, OperatorIdentityId, Proposal, ProposalId,
+            ProposalStatus, RecoveryOperatorIdentityId, SqliteTimestamp,
+        },
+        proposal::{ProposalKind, ProposalKindTag},
+    },
+};
+use chrono::Utc;
+use kameo::{Actor, actor::ActorRef, messages};
+use kameo_actors::message_bus::{MessageBus, Publish};
+use std::sync::Arc;
+use tracing::warn;
+
+pub mod events;
+pub mod store;
+
+pub const DEFAULT_TTL_SECS: u32 = 7 * 24 * 60 * 60; // 7 days
+pub const MAX_TTL_SECS: u32 = DEFAULT_TTL_SECS;
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum VoteOutcome {
+    Pending,
+    Approved,
+    Rejected,
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("Proposal not found")]
+    ProposalNotFound,
+    #[error("Proposal is not pending")]
+    ProposalNotPending,
+    #[error("Proposal has expired")]
+    ProposalExpired,
+    #[error("Requested TTL exceeds the maximum of {} seconds", MAX_TTL_SECS)]
+    TtlTooLong,
+    #[error("Operator already voted on this proposal")]
+    AlreadyVoted,
+    #[error("Invalid vote signature")]
+    InvalidSignature,
+    #[error("Operator not found")]
+    OperatorNotFound,
+    #[error("Database connection error: {0}")]
+    DatabaseConnection(#[from] db::PoolError),
+    #[error("Database query error: {0}")]
+    DatabaseQuery(#[from] diesel::result::Error),
+    #[error("Proposal manager is unavailable")]
+    Unavailable,
+    #[error("Recovery operators are sleeping")]
+    RecoveryNotActive,
+    #[error("Recovery operators may only vote on operator replacement")]
+    NotAllowedForRecoveryOperator,
+    #[error("A recovery wake-up is already pending or active")]
+    WakeupAlreadyPending,
+    #[error("No active recovery wake-up to cancel")]
+    NoActiveWakeup,
+}
+
+#[derive(Debug)]
+pub struct ProposalSummary {
+    pub id: ProposalId,
+    pub kind: ProposalKindTag,
+    pub initiator_id: OperatorIdentityId,
+    pub expires_at: SqliteTimestamp,
+    pub approve_count: i64,
+    pub reject_count: i64,
+}
+
+#[derive(Actor)]
+pub struct ProposalManager {
+    pub(crate) store: Arc<dyn ProposalStore>,
+    pub(crate) events: ActorRef<MessageBus>,
+}
+
+impl ProposalManager {
+    pub fn new(db: db::DatabasePool, events: ActorRef<MessageBus>) -> Self {
+        Self::with_store(Arc::new(DieselProposalStore::new(db)), events)
+    }
+
+    /// Builds the actor over an arbitrary store, so tests can supply a mock.
+    pub(crate) const fn with_store(
+        store: Arc<dyn ProposalStore>,
+        events: ActorRef<MessageBus>,
+    ) -> Self {
+        Self { store, events }
+    }
+}
+
+#[messages]
+impl ProposalManager {
+    #[message]
+    pub async fn create_proposal(
+        &mut self,
+        kind: ProposalKind,
+        initiator_id: OperatorIdentityId,
+        ttl_secs: Option<u32>,
+    ) -> Result<ProposalId, Error> {
+        let ttl = ttl_secs.unwrap_or(DEFAULT_TTL_SECS);
+        if ttl > MAX_TTL_SECS {
+            return Err(Error::TtlTooLong);
+        }
+        let expires_at =
+            SqliteTimestamp::from(Utc::now() + chrono::Duration::seconds(i64::from(ttl)));
+
+        self.store.create(kind, initiator_id, expires_at).await
+    }
+
+    #[message]
+    pub async fn query_pending(&mut self, operator_id: OperatorIdentityId) -> Vec<ProposalSummary> {
+        self.store
+            .pending_for(operator_id)
+            .await
+            .unwrap_or_else(|e| {
+                warn!(?e, "query_pending failed");
+                vec![]
+            })
+    }
+
+    #[message]
+    pub async fn cast_vote(
+        &mut self,
+        proposal_id: ProposalId,
+        operator_id: OperatorIdentityId,
+        approve: bool,
+        signature: Vec<u8>,
+    ) -> Result<VoteOutcome, Error> {
+        let proposal = self.store.load(proposal_id).await?;
+
+        // Checked before the status check so AlreadyVoted takes priority.
+        if self.store.has_voted(proposal_id, operator_id).await? {
+            return Err(Error::AlreadyVoted);
+        }
+
+        Self::check_votable(&proposal)?;
+
+        let public_key = self.store.operator_public_key(operator_id).await?;
+        governance::verify_vote(&public_key, proposal_id, approve, &signature)
+            .map_err(|_| Error::InvalidSignature)?;
+
+        self.store
+            .record_vote(NewProposalVote {
+                proposal_id,
+                operator_id,
+                approve,
+                signature,
+            })
+            .await?;
+
+        let mut tally = self.store.tally(proposal_id).await?;
+        self.narrow_electorate(&proposal, &mut tally).await?;
+
+        self.settle(&proposal, &tally).await
+    }
+
+    /// §3.6: Any ordinary operator may request recovery wake-up.
+    /// Fails if a wake-up is already pending or active.
+    #[message]
+    pub async fn request_recovery_wakeup(
+        &mut self,
+        operator_id: OperatorIdentityId,
+    ) -> Result<(), Error> {
+        if self.store.has_uncancelled_wakeup().await? {
+            return Err(Error::WakeupAlreadyPending);
+        }
+        self.store.request_wakeup(operator_id).await
+    }
+
+    /// §3.6: Any ordinary operator may cancel a pending wake-up request.
+    /// Fails if there is no uncancelled request.
+    #[message]
+    pub async fn cancel_recovery_wakeup(
+        &mut self,
+        operator_id: OperatorIdentityId,
+    ) -> Result<(), Error> {
+        if self.store.cancel_wakeup(operator_id).await? {
+            Ok(())
+        } else {
+            Err(Error::NoActiveWakeup)
+        }
+    }
+
+    /// §3.5: Recovery operators may only vote on operator replacement proposals.
+    /// §3.6: Voting is gated behind recovery being active (14-day window elapsed).
+    #[message]
+    pub async fn cast_recovery_vote(
+        &mut self,
+        proposal_id: ProposalId,
+        recovery_operator_id: RecoveryOperatorIdentityId,
+        approve: bool,
+        signature: Vec<u8>,
+    ) -> Result<VoteOutcome, Error> {
+        let proposal = self.store.load(proposal_id).await?;
+
+        if proposal.kind != ProposalKindTag::ReplaceOperator {
+            return Err(Error::NotAllowedForRecoveryOperator);
+        }
+
+        if !self.store.is_recovery_active().await? {
+            return Err(Error::RecoveryNotActive);
+        }
+
+        if self
+            .store
+            .has_recovery_voted(proposal_id, recovery_operator_id)
+            .await?
+        {
+            return Err(Error::AlreadyVoted);
+        }
+
+        Self::check_votable(&proposal)?;
+
+        let public_key = self
+            .store
+            .recovery_operator_public_key(recovery_operator_id)
+            .await?;
+        governance::verify_vote(&public_key, proposal_id, approve, &signature)
+            .map_err(|_| Error::InvalidSignature)?;
+
+        self.store
+            .record_recovery_vote(NewRecoveryProposalVote {
+                proposal_id,
+                recovery_operator_id,
+                approve,
+                signature,
+            })
+            .await?;
+
+        let mut tally = self.store.tally(proposal_id).await?;
+        self.narrow_electorate(&proposal, &mut tally).await?;
+
+        self.settle(&proposal, &tally).await
+    }
+}
+
+impl ProposalManager {
+    /// A vote only counts while the proposal is still open.
+    fn check_votable(proposal: &Proposal) -> Result<(), Error> {
+        if proposal.status != ProposalStatus::Pending {
+            return Err(Error::ProposalNotPending);
+        }
+        if proposal.expires_at.0 <= Utc::now() {
+            return Err(Error::ProposalExpired);
+        }
+        Ok(())
+    }
+
+    /// §3.5/§3.6: recovery operators join the electorate only for the kinds they may vote on,
+    /// and only once the wake-up window has elapsed. Counting them anywhere else makes the
+    /// rejection threshold unreachable and, for full-quorum kinds, approval unreachable too.
+    ///
+    /// The votes go out with the voters. A wake-up can be cancelled after recovery operators
+    /// have already voted (`cancel_wakeup` cancels any uncancelled request, elapsed or not),
+    /// so a `ReplaceOperator` tally can hold recovery approvals at the moment the committee
+    /// stops being eligible. Keeping those while zeroing only the electorate size would let
+    /// them cover ordinary votes that were never cast.
+    async fn narrow_electorate(&self, proposal: &Proposal, tally: &mut Tally) -> Result<(), Error> {
+        if !proposal.kind.recovery_may_vote() || !self.store.is_recovery_active().await? {
+            tally.drop_recovery();
+        }
+        Ok(())
+    }
+
+    /// Pure quorum arithmetic — no I/O, so the rules can be tested directly (§3.3).
+    ///
+    /// A proposal is rejected once approval has become unreachable: even if every voter
+    /// who has not spoken yet approved, the threshold could not be met.
+    #[must_use]
+    pub(crate) const fn evaluate_quorum(tally: &Tally, requires_full_quorum: bool) -> VoteOutcome {
+        let total_eligible = tally.total_ordinary + tally.total_recovery;
+
+        // No electorate, nothing to settle. Guarded before the branch rather than inside it:
+        // the full-quorum arm would otherwise set `threshold` to 0 and read an empty tally as
+        // unanimous approval.
+        if total_eligible <= 0 {
+            return VoteOutcome::Pending;
+        }
+
+        #[expect(
+            clippy::cast_possible_truncation,
+            clippy::cast_sign_loss,
+            clippy::cast_possible_wrap,
+            clippy::as_conversions,
+            reason = "operator counts are always small positive integers"
+        )]
+        // §3.3: key-rotation proposals require every eligible voter to approve.
+        // §3.5: when recovery is active, recovery operators are eligible too.
+        let threshold: i64 = if requires_full_quorum {
+            total_eligible
+        } else {
+            match crate::crypto::shamir::shamir_threshold(tally.total_ordinary as usize) {
+                Some(threshold) => threshold as i64,
+                // No ordinary operators means no electorate: nothing can settle.
+                None => return VoteOutcome::Pending,
+            }
+        };
+
+        if tally.approve() >= threshold {
+            VoteOutcome::Approved
+        } else if tally.reject() > total_eligible - threshold {
+            VoteOutcome::Rejected
+        } else {
+            VoteOutcome::Pending
+        }
+    }
+
+    /// Applies the quorum rules to a fresh tally and records whatever they decide.
+    async fn settle(&self, proposal: &Proposal, tally: &Tally) -> Result<VoteOutcome, Error> {
+        let outcome = Self::evaluate_quorum(tally, proposal.kind.requires_full_quorum());
+
+        match outcome {
+            VoteOutcome::Approved => self.announce_approval(proposal).await?,
+            VoteOutcome::Rejected => {
+                self.store
+                    .set_status(proposal.id, ProposalStatus::Rejected)
+                    .await?;
+            }
+            VoteOutcome::Pending => {}
+        }
+
+        Ok(outcome)
+    }
+
+    /// Marks the proposal approved and hands the outcome to whoever owns that kind.
+    ///
+    /// The outcome is published, not executed: this actor coordinates voting and nothing
+    /// else. Executors subscribe on the bus, so a vote is answered once the quorum is
+    /// recorded rather than once the effect has landed.
+    async fn announce_approval(&self, proposal: &Proposal) -> Result<(), Error> {
+        self.store
+            .set_status(proposal.id, ProposalStatus::Approved)
+            .await?;
+
+        let kind = self.store.load_kind(proposal.id, proposal.kind).await?;
+        let _ = self
+            .events
+            .tell(Publish(ProposalApproved {
+                id: proposal.id,
+                kind,
+            }))
+            .await;
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests;

server/crates/arbiter-server/src/actors/proposal_manager/events.rs

@@ -0,0 +1,11 @@
+use crate::db::{models::ProposalId, proposal::ProposalKind};
+
+/// Published once a proposal reaches its approval threshold.
+///
+/// Executors subscribe on the global `MessageBus` and act on the kinds they own;
+/// `ProposalManager` does not know who acts on an outcome, or whether anyone does.
+#[derive(Debug, Clone)]
+pub struct ProposalApproved {
+    pub id: ProposalId,
+    pub kind: ProposalKind,
+}

server/crates/arbiter-server/src/actors/proposal_manager/store.rs

@@ -0,0 +1,431 @@
+//! Database access for [`super::ProposalManager`], behind a trait.
+//!
+//! The actor holds a `dyn ProposalStore` rather than a connection pool, so the quorum
+//! rules can be exercised against a mock instead of a live SQLite file.
+
+use super::{Error, ProposalSummary};
+use crate::db::{
+    self,
+    models::{
+        NewProposal, NewProposalVote, NewRecoveryProposalVote, NewRecoveryWakeupRequest,
+        OperatorIdentityId, Proposal, ProposalId, ProposalStatus, RecoveryOperatorIdentityId,
+        SqliteTimestamp,
+    },
+    proposal::{ProposalKind, ProposalKindTag},
+    schema,
+};
+
+use async_trait::async_trait;
+use chrono::Utc;
+use diesel::{
+    ExpressionMethods as _, QueryDsl,
+    dsl::{exists, select},
+};
+use diesel_async::{AsyncConnection as _, RunQueryDsl};
+use std::collections::HashMap;
+use strum::IntoDiscriminant as _;
+
+/// Everything the quorum rules need to know about one proposal's votes.
+///
+/// Votes are kept per electorate rather than pre-summed: an electorate can stop counting
+/// between the vote and the tally (§3.6 -- recovery goes back to sleep the moment a wake-up
+/// is cancelled), and the votes it already cast have to leave with it. A single `approve`
+/// field would carry them past [`Tally::drop_recovery`] into a threshold computed for the
+/// ordinary committee alone.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct Tally {
+    pub ordinary_approve: i64,
+    pub ordinary_reject: i64,
+    pub recovery_approve: i64,
+    pub recovery_reject: i64,
+    pub total_ordinary: i64,
+    pub total_recovery: i64,
+}
+
+impl Tally {
+    /// Approvals from every electorate that still counts.
+    pub const fn approve(&self) -> i64 {
+        self.ordinary_approve + self.recovery_approve
+    }
+
+    /// Rejections from every electorate that still counts.
+    pub const fn reject(&self) -> i64 {
+        self.ordinary_reject + self.recovery_reject
+    }
+
+    /// Takes the recovery committee out of the electorate, votes and all. The three numbers
+    /// go together: leaving the votes behind counts them against a threshold derived from an
+    /// electorate they are no longer part of.
+    pub const fn drop_recovery(&mut self) {
+        self.recovery_approve = 0;
+        self.recovery_reject = 0;
+        self.total_recovery = 0;
+    }
+}
+
+#[cfg_attr(test, mockall::automock)]
+#[async_trait]
+pub trait ProposalStore: Send + Sync + 'static {
+    /// Writes the proposal and its kind-specific rows in one transaction.
+    async fn create(
+        &self,
+        kind: ProposalKind,
+        initiator_id: OperatorIdentityId,
+        expires_at: SqliteTimestamp,
+    ) -> Result<ProposalId, Error>;
+
+    async fn load(&self, id: ProposalId) -> Result<Proposal, Error>;
+
+    async fn load_kind(&self, id: ProposalId, tag: ProposalKindTag) -> Result<ProposalKind, Error>;
+
+    async fn has_voted(
+        &self,
+        id: ProposalId,
+        operator_id: OperatorIdentityId,
+    ) -> Result<bool, Error>;
+
+    async fn has_recovery_voted(
+        &self,
+        id: ProposalId,
+        recovery_operator_id: RecoveryOperatorIdentityId,
+    ) -> Result<bool, Error>;
+
+    async fn operator_public_key(&self, id: OperatorIdentityId) -> Result<Vec<u8>, Error>;
+
+    async fn recovery_operator_public_key(
+        &self,
+        id: RecoveryOperatorIdentityId,
+    ) -> Result<Vec<u8>, Error>;
+
+    async fn record_vote(&self, vote: NewProposalVote) -> Result<(), Error>;
+
+    async fn record_recovery_vote(&self, vote: NewRecoveryProposalVote) -> Result<(), Error>;
+
+    /// Vote counts for one proposal, alongside the size of each electorate.
+    async fn tally(&self, id: ProposalId) -> Result<Tally, Error>;
+
+    async fn set_status(&self, id: ProposalId, status: ProposalStatus) -> Result<(), Error>;
+
+    /// Pending, unexpired proposals this operator has not voted on yet.
+    async fn pending_for(
+        &self,
+        operator_id: OperatorIdentityId,
+    ) -> Result<Vec<ProposalSummary>, Error>;
+
+    /// True once an uncancelled wake-up request has outlived the dispute window.
+    async fn is_recovery_active(&self) -> Result<bool, Error>;
+
+    /// True while any wake-up request stands, whether or not the window has elapsed.
+    async fn has_uncancelled_wakeup(&self) -> Result<bool, Error>;
+
+    async fn request_wakeup(&self, operator_id: OperatorIdentityId) -> Result<(), Error>;
+
+    /// Returns false when there was no uncancelled request to cancel.
+    async fn cancel_wakeup(&self, operator_id: OperatorIdentityId) -> Result<bool, Error>;
+}
+
+pub struct DieselProposalStore {
+    db: db::DatabasePool,
+}
+
+impl DieselProposalStore {
+    pub const fn new(db: db::DatabasePool) -> Self {
+        Self { db }
+    }
+}
+
+/// `NotFound` means the row is absent, which every caller reports as its own error.
+fn missing(absent: Error) -> impl FnOnce(diesel::result::Error) -> Error {
+    move |e| match e {
+        diesel::result::Error::NotFound => absent,
+        other => Error::DatabaseQuery(other),
+    }
+}
+
+#[async_trait]
+impl ProposalStore for DieselProposalStore {
+    async fn create(
+        &self,
+        kind: ProposalKind,
+        initiator_id: OperatorIdentityId,
+        expires_at: SqliteTimestamp,
+    ) -> Result<ProposalId, Error> {
+        let id = self
+            .db
+            .get()
+            .await?
+            .transaction(async |conn| {
+                let id: ProposalId = diesel::insert_into(schema::proposal::table)
+                    .values(&NewProposal {
+                        kind: kind.discriminant(),
+                        initiator_id,
+                        expires_at,
+                    })
+                    .returning(schema::proposal::id)
+                    .get_result(conn)
+                    .await?;
+                db::proposal::insert_kind(conn, id, &kind).await?;
+                Ok::<_, diesel::result::Error>(id)
+            })
+            .await?;
+
+        Ok(id)
+    }
+
+    async fn load(&self, id: ProposalId) -> Result<Proposal, Error> {
+        let mut conn = self.db.get().await?;
+        schema::proposal::table
+            .find(id)
+            .first(&mut conn)
+            .await
+            .map_err(missing(Error::ProposalNotFound))
+    }
+
+    async fn load_kind(&self, id: ProposalId, tag: ProposalKindTag) -> Result<ProposalKind, Error> {
+        let mut conn = self.db.get().await?;
+        db::proposal::load_kind(&mut conn, id, tag)
+            .await
+            .map_err(Error::from)
+    }
+
+    async fn has_voted(
+        &self,
+        id: ProposalId,
+        operator_id: OperatorIdentityId,
+    ) -> Result<bool, Error> {
+        let mut conn = self.db.get().await?;
+        select(exists(
+            schema::proposal_vote::table
+                .filter(schema::proposal_vote::proposal_id.eq(id))
+                .filter(schema::proposal_vote::operator_id.eq(operator_id)),
+        ))
+        .get_result(&mut conn)
+        .await
+        .map_err(Error::from)
+    }
+
+    async fn has_recovery_voted(
+        &self,
+        id: ProposalId,
+        recovery_operator_id: RecoveryOperatorIdentityId,
+    ) -> Result<bool, Error> {
+        let mut conn = self.db.get().await?;
+        select(exists(
+            schema::recovery_proposal_vote::table
+                .filter(schema::recovery_proposal_vote::proposal_id.eq(id))
+                .filter(
+                    schema::recovery_proposal_vote::recovery_operator_id.eq(recovery_operator_id),
+                ),
+        ))
+        .get_result(&mut conn)
+        .await
+        .map_err(Error::from)
+    }
+
+    async fn operator_public_key(&self, id: OperatorIdentityId) -> Result<Vec<u8>, Error> {
+        let mut conn = self.db.get().await?;
+        schema::operator_identity::table
+            .find(id)
+            .select(schema::operator_identity::public_key)
+            .first(&mut conn)
+            .await
+            .map_err(missing(Error::OperatorNotFound))
+    }
+
+    async fn recovery_operator_public_key(
+        &self,
+        id: RecoveryOperatorIdentityId,
+    ) -> Result<Vec<u8>, Error> {
+        let mut conn = self.db.get().await?;
+        schema::recovery_operator_identity::table
+            .find(id)
+            .select(schema::recovery_operator_identity::public_key)
+            .first(&mut conn)
+            .await
+            .map_err(missing(Error::OperatorNotFound))
+    }
+
+    async fn record_vote(&self, vote: NewProposalVote) -> Result<(), Error> {
+        let mut conn = self.db.get().await?;
+        diesel::insert_into(schema::proposal_vote::table)
+            .values(&vote)
+            .execute(&mut conn)
+            .await?;
+        Ok(())
+    }
+
+    async fn record_recovery_vote(&self, vote: NewRecoveryProposalVote) -> Result<(), Error> {
+        let mut conn = self.db.get().await?;
+        diesel::insert_into(schema::recovery_proposal_vote::table)
+            .values(&vote)
+            .execute(&mut conn)
+            .await?;
+        Ok(())
+    }
+
+    async fn tally(&self, id: ProposalId) -> Result<Tally, Error> {
+        let mut conn = self.db.get().await?;
+
+        let ordinary_approve: i64 = schema::proposal_vote::table
+            .filter(schema::proposal_vote::proposal_id.eq(id))
+            .filter(schema::proposal_vote::approve.eq(true))
+            .count()
+            .get_result(&mut conn)
+            .await?;
+        let recovery_approve: i64 = schema::recovery_proposal_vote::table
+            .filter(schema::recovery_proposal_vote::proposal_id.eq(id))
+            .filter(schema::recovery_proposal_vote::approve.eq(true))
+            .count()
+            .get_result(&mut conn)
+            .await?;
+
+        let ordinary_reject: i64 = schema::proposal_vote::table
+            .filter(schema::proposal_vote::proposal_id.eq(id))
+            .filter(schema::proposal_vote::approve.eq(false))
+            .count()
+            .get_result(&mut conn)
+            .await?;
+        let recovery_reject: i64 = schema::recovery_proposal_vote::table
+            .filter(schema::recovery_proposal_vote::proposal_id.eq(id))
+            .filter(schema::recovery_proposal_vote::approve.eq(false))
+            .count()
+            .get_result(&mut conn)
+            .await?;
+
+        let total_ordinary: i64 = schema::operator_identity::table
+            .count()
+            .get_result(&mut conn)
+            .await?;
+        let total_recovery: i64 = schema::recovery_operator_identity::table
+            .count()
+            .get_result(&mut conn)
+            .await?;
+
+        Ok(Tally {
+            ordinary_approve,
+            ordinary_reject,
+            recovery_approve,
+            recovery_reject,
+            total_ordinary,
+            total_recovery,
+        })
+    }
+
+    async fn set_status(&self, id: ProposalId, status: ProposalStatus) -> Result<(), Error> {
+        let mut conn = self.db.get().await?;
+        diesel::update(schema::proposal::table.find(id))
+            .set(schema::proposal::status.eq(status))
+            .execute(&mut conn)
+            .await?;
+        Ok(())
+    }
+
+    async fn pending_for(
+        &self,
+        operator_id: OperatorIdentityId,
+    ) -> Result<Vec<ProposalSummary>, Error> {
+        #[expect(
+            clippy::cast_possible_truncation,
+            clippy::as_conversions,
+            reason = "fixme! #84; this will break in 2038"
+        )]
+        let now_ts = Utc::now().timestamp() as i32;
+
+        let mut conn = self.db.get().await?;
+
+        let voted_ids: Vec<ProposalId> = schema::proposal_vote::table
+            .filter(schema::proposal_vote::operator_id.eq(operator_id))
+            .select(schema::proposal_vote::proposal_id)
+            .load(&mut conn)
+            .await?;
+
+        let proposals: Vec<Proposal> = schema::proposal::table
+            .filter(schema::proposal::status.eq(ProposalStatus::Pending))
+            .filter(schema::proposal::expires_at.gt(now_ts))
+            .filter(diesel::dsl::not(schema::proposal::id.eq_any(&voted_ids)))
+            .load(&mut conn)
+            .await?;
+
+        let ids: Vec<ProposalId> = proposals.iter().map(|p| p.id).collect();
+        let tallies: Vec<(ProposalId, bool, i64)> = schema::proposal_vote::table
+            .filter(schema::proposal_vote::proposal_id.eq_any(&ids))
+            .group_by((
+                schema::proposal_vote::proposal_id,
+                schema::proposal_vote::approve,
+            ))
+            .select((
+                schema::proposal_vote::proposal_id,
+                schema::proposal_vote::approve,
+                diesel::dsl::count_star(),
+            ))
+            .load(&mut conn)
+            .await?;
+
+        let mut by_proposal: HashMap<ProposalId, (i64, i64)> = HashMap::new();
+        for (proposal_id, approve, count) in tallies {
+            let entry = by_proposal.entry(proposal_id).or_insert((0, 0));
+            if approve {
+                entry.0 += count;
+            } else {
+                entry.1 += count;
+            }
+        }
+
+        Ok(proposals
+            .into_iter()
+            .map(|p| {
+                let (approve_count, reject_count) =
+                    by_proposal.get(&p.id).copied().unwrap_or((0, 0));
+                ProposalSummary {
+                    id: p.id,
+                    kind: p.kind,
+                    initiator_id: p.initiator_id,
+                    expires_at: p.expires_at,
+                    approve_count,
+                    reject_count,
+                }
+            })
+            .collect())
+    }
+
+    async fn is_recovery_active(&self) -> Result<bool, Error> {
+        let mut conn = self.db.get().await?;
+        db::recovery::is_active(&mut conn)
+            .await
+            .map_err(Error::from)
+    }
+
+    async fn has_uncancelled_wakeup(&self) -> Result<bool, Error> {
+        let mut conn = self.db.get().await?;
+        select(exists(schema::recovery_wakeup_request::table.filter(
+            schema::recovery_wakeup_request::cancelled_at.is_null(),
+        )))
+        .get_result(&mut conn)
+        .await
+        .map_err(Error::from)
+    }
+
+    async fn request_wakeup(&self, operator_id: OperatorIdentityId) -> Result<(), Error> {
+        let mut conn = self.db.get().await?;
+        diesel::insert_into(schema::recovery_wakeup_request::table)
+            .values(&NewRecoveryWakeupRequest {
+                requested_by: operator_id,
+            })
+            .execute(&mut conn)
+            .await?;
+        Ok(())
+    }
+
+    async fn cancel_wakeup(&self, operator_id: OperatorIdentityId) -> Result<bool, Error> {
+        let mut conn = self.db.get().await?;
+        let rows = diesel::update(schema::recovery_wakeup_request::table)
+            .filter(schema::recovery_wakeup_request::cancelled_at.is_null())
+            .set((
+                schema::recovery_wakeup_request::cancelled_by.eq(Some(operator_id)),
+                schema::recovery_wakeup_request::cancelled_at.eq(Some(SqliteTimestamp::now())),
+            ))
+            .execute(&mut conn)
+            .await?;
+        Ok(rows > 0)
+    }
+}

server/crates/arbiter-server/src/actors/proposal_manager/tests.rs

@@ -0,0 +1,395 @@
+//! The quorum rules, exercised without a database.
+//!
+//! These assertions are the point of [`super::store::ProposalStore`]: until the actor took
+//! its data through a trait, checking that two of three operators carry an ordinary
+//! proposal meant opening SQLite and registering operators first.
+
+use super::{
+    ProposalManager, VoteOutcome,
+    store::{MockProposalStore, Tally},
+};
+use crate::{
+    actors::GlobalActors,
+    crypto::governance::vote_message,
+    db::{
+        models::{OperatorIdentityId, Proposal, ProposalId, ProposalStatus, SqliteTimestamp},
+        proposal::ProposalKindTag,
+    },
+};
+use arbiter_crypto::authn::{SigningContext, SigningKey};
+use chrono::{Duration, Utc};
+use std::sync::Arc;
+
+/// A tally where every vote came from the ordinary committee.
+const fn tally(approve: i64, reject: i64, ordinary: i64, recovery: i64) -> Tally {
+    Tally {
+        ordinary_approve: approve,
+        ordinary_reject: reject,
+        recovery_approve: 0,
+        recovery_reject: 0,
+        total_ordinary: ordinary,
+        total_recovery: recovery,
+    }
+}
+
+/// A tally with votes from both committees, in the order approve/reject per committee.
+const fn mixed_tally(
+    ordinary_approve: i64,
+    ordinary_reject: i64,
+    recovery_approve: i64,
+    recovery_reject: i64,
+    total_ordinary: i64,
+    total_recovery: i64,
+) -> Tally {
+    Tally {
+        ordinary_approve,
+        ordinary_reject,
+        recovery_approve,
+        recovery_reject,
+        total_ordinary,
+        total_recovery,
+    }
+}
+
+#[test]
+fn simple_majority_approves_at_two_of_three() {
+    assert_eq!(
+        ProposalManager::evaluate_quorum(&tally(2, 0, 3, 0), false),
+        VoteOutcome::Approved
+    );
+}
+
+#[test]
+fn one_of_three_is_not_yet_a_majority() {
+    assert_eq!(
+        ProposalManager::evaluate_quorum(&tally(1, 0, 3, 0), false),
+        VoteOutcome::Pending
+    );
+}
+
+#[test]
+fn full_quorum_kind_needs_every_voter() {
+    assert_eq!(
+        ProposalManager::evaluate_quorum(&tally(2, 0, 3, 0), true),
+        VoteOutcome::Pending,
+        "two of three must not carry a key-rotation proposal"
+    );
+}
+
+#[test]
+fn recovery_voters_count_towards_full_quorum() {
+    assert_eq!(
+        ProposalManager::evaluate_quorum(&mixed_tally(2, 0, 1, 0, 2, 1), true),
+        VoteOutcome::Approved
+    );
+    assert_eq!(
+        ProposalManager::evaluate_quorum(&mixed_tally(2, 0, 0, 0, 2, 1), true),
+        VoteOutcome::Pending,
+        "the sleeping recovery operator still owes a vote"
+    );
+}
+
+/// An empty committee cannot approve anything. Both arms have to say so: the full-quorum arm
+/// derives its threshold from the electorate, so with nobody eligible it would compare 0
+/// approvals against a threshold of 0 and call that unanimous.
+#[test]
+fn an_empty_electorate_settles_nothing() {
+    assert_eq!(
+        ProposalManager::evaluate_quorum(&tally(0, 0, 0, 0), true),
+        VoteOutcome::Pending,
+        "a full-quorum proposal must not pass with no eligible voters"
+    );
+    assert_eq!(
+        ProposalManager::evaluate_quorum(&tally(0, 0, 0, 0), false),
+        VoteOutcome::Pending
+    );
+}
+
+#[test]
+fn rejection_is_decided_once_approval_is_unreachable() {
+    // Threshold is 2 of 3, so two rejections leave at most one approval available.
+    assert_eq!(
+        ProposalManager::evaluate_quorum(&tally(0, 2, 3, 0), false),
+        VoteOutcome::Rejected
+    );
+    assert_eq!(
+        ProposalManager::evaluate_quorum(&tally(0, 1, 3, 0), false),
+        VoteOutcome::Pending,
+        "one rejection still leaves two approvals reachable"
+    );
+}
+
+#[test]
+fn a_single_rejection_sinks_a_full_quorum_proposal() {
+    assert_eq!(
+        ProposalManager::evaluate_quorum(&tally(2, 1, 3, 0), true),
+        VoteOutcome::Rejected
+    );
+}
+
+fn pending_proposal(id: ProposalId, kind: ProposalKindTag) -> Proposal {
+    let now = Utc::now();
+    Proposal {
+        id,
+        kind,
+        initiator_id: OperatorIdentityId::from_raw(1),
+        created_at: SqliteTimestamp::from(now),
+        expires_at: SqliteTimestamp::from(now + Duration::days(1)),
+        status: ProposalStatus::Pending,
+    }
+}
+
+/// The mock earns its keep here: reaching quorum must flip the stored status to
+/// `Approved` exactly once. Signature verification stays real -- only the database is
+/// stubbed out.
+#[tokio::test]
+async fn reaching_quorum_marks_the_proposal_approved() {
+    let id = ProposalId::from_raw(1);
+    let voter = OperatorIdentityId::from_raw(1);
+    let key = SigningKey::generate();
+    let signature = key
+        .sign_message(&vote_message(id, true), SigningContext::GovernanceVote)
+        .expect("signing a vote must succeed");
+    let public_key = key.public_key().to_bytes();
+
+    let mut store = MockProposalStore::new();
+    store
+        .expect_load()
+        .returning(move |id| Ok(pending_proposal(id, ProposalKindTag::TriggerRekey)));
+    store.expect_has_voted().returning(|_, _| Ok(false));
+    store
+        .expect_operator_public_key()
+        .returning(move |_| Ok(public_key.clone()));
+    store.expect_record_vote().returning(|_| Ok(()));
+    store.expect_is_recovery_active().returning(|| Ok(false));
+    store.expect_tally().returning(|_| Ok(tally(1, 0, 1, 0)));
+    store
+        .expect_set_status()
+        .withf(move |got, status| *got == id && *status == ProposalStatus::Approved)
+        .times(1)
+        .returning(|_, _| Ok(()));
+    store
+        .expect_load_kind()
+        .returning(|_, _| Ok(crate::db::proposal::ProposalKind::TriggerRekey));
+
+    let mut manager =
+        ProposalManager::with_store(Arc::new(store), GlobalActors::spawn_message_bus());
+
+    let outcome = manager
+        .cast_vote(id, voter, true, signature.to_bytes())
+        .await
+        .expect("a valid vote must be accepted");
+
+    assert_eq!(outcome, VoteOutcome::Approved);
+}
+
+/// A vote that does not reach the threshold must leave the stored status alone.
+#[tokio::test]
+async fn a_vote_short_of_quorum_does_not_touch_the_status() {
+    let id = ProposalId::from_raw(7);
+    let voter = OperatorIdentityId::from_raw(2);
+    let key = SigningKey::generate();
+    let signature = key
+        .sign_message(&vote_message(id, true), SigningContext::GovernanceVote)
+        .expect("signing a vote must succeed");
+    let public_key = key.public_key().to_bytes();
+
+    let mut store = MockProposalStore::new();
+    store
+        .expect_load()
+        .returning(move |id| Ok(pending_proposal(id, ProposalKindTag::ApproveSdkClient)));
+    store.expect_has_voted().returning(|_, _| Ok(false));
+    store
+        .expect_operator_public_key()
+        .returning(move |_| Ok(public_key.clone()));
+    store.expect_record_vote().returning(|_| Ok(()));
+    store.expect_is_recovery_active().returning(|| Ok(false));
+    store.expect_tally().returning(|_| Ok(tally(1, 0, 3, 0)));
+    store.expect_set_status().never();
+
+    let mut manager =
+        ProposalManager::with_store(Arc::new(store), GlobalActors::spawn_message_bus());
+
+    let outcome = manager
+        .cast_vote(id, voter, true, signature.to_bytes())
+        .await
+        .expect("a valid vote must be accepted");
+
+    assert_eq!(outcome, VoteOutcome::Pending);
+}
+
+/// Drives one `cast_vote` on a proposal of the given `kind` through a mocked store and
+/// returns the outcome. `recovery_active` decides what `is_recovery_active` reports;
+/// `expected_status` is the status a settled outcome must be persisted under, or `None` for
+/// a caller that expects the vote to leave the proposal pending.
+///
+/// `set_status` carries an argument matcher but no `.times()`, and `None` relaxes even the
+/// matcher: the caller's own `assert_eq!` on the outcome is what pins the behaviour, so a
+/// regression fails on a readable diff rather than on a mockall cardinality panic that hides
+/// what the actor actually computed.
+async fn settle_vote_with(
+    kind: ProposalKindTag,
+    tally: Tally,
+    recovery_active: bool,
+    expected_status: Option<ProposalStatus>,
+) -> VoteOutcome {
+    let id = ProposalId::from_raw(11);
+    let voter = OperatorIdentityId::from_raw(1);
+    let key = SigningKey::generate();
+    let signature = key
+        .sign_message(&vote_message(id, true), SigningContext::GovernanceVote)
+        .expect("signing a vote must succeed");
+    let public_key = key.public_key().to_bytes();
+
+    let mut store = MockProposalStore::new();
+    store
+        .expect_load()
+        .returning(move |id| Ok(pending_proposal(id, kind)));
+    store.expect_has_voted().returning(|_, _| Ok(false));
+    store
+        .expect_operator_public_key()
+        .returning(move |_| Ok(public_key.clone()));
+    store.expect_record_vote().returning(|_| Ok(()));
+    store
+        .expect_is_recovery_active()
+        .returning(move || Ok(recovery_active));
+    store.expect_tally().returning(move |_| Ok(tally));
+    store
+        .expect_set_status()
+        .withf(move |_, status| {
+            expected_status
+                .as_ref()
+                .is_none_or(|expected| status == expected)
+        })
+        .returning(|_, _| Ok(()));
+    store.expect_load_kind().returning(move |_, _| {
+        Ok(match kind {
+            ProposalKindTag::TriggerRekey => crate::db::proposal::ProposalKind::TriggerRekey,
+            ProposalKindTag::ApproveSdkClient => {
+                crate::db::proposal::ProposalKind::ApproveSdkClient(
+                    crate::db::proposal::approve_sdk_client::Settings { client_id: 1 },
+                )
+            }
+            ProposalKindTag::ReplaceOperator => crate::db::proposal::ProposalKind::ReplaceOperator(
+                crate::db::proposal::replace_operator::Settings {
+                    old_operator_id: OperatorIdentityId::from_raw(1),
+                    new_pubkey: vec![0u8; 32],
+                },
+            ),
+            other => unreachable!("settle_vote_with has no load_kind fixture for {other:?}"),
+        })
+    });
+
+    let mut manager =
+        ProposalManager::with_store(Arc::new(store), GlobalActors::spawn_message_bus());
+
+    manager
+        .cast_vote(id, voter, true, signature.to_bytes())
+        .await
+        .expect("a valid vote must be accepted")
+}
+
+/// The full-quorum rejection path is insensitive to electorate size by construction:
+/// `threshold == total_eligible` there, so `total_eligible - threshold` is always 0 and any
+/// single rejection settles the proposal, whether or not recovery operators are (wrongly)
+/// counted. This does not exercise the electorate-narrowing fix -- see
+/// `unanimous_ordinary_rejection_rejects_a_non_full_quorum_proposal_while_recovery_is_awake`
+/// below for the test that does -- it just pins that `cast_vote` still writes `Rejected`
+/// through `settle` for a full-quorum kind.
+#[tokio::test]
+async fn unanimous_rejection_settles_a_full_quorum_rekey_via_cast_vote() {
+    let outcome = settle_vote_with(
+        ProposalKindTag::TriggerRekey,
+        tally(0, 3, 3, 2),
+        /* recovery_active */ true,
+        Some(ProposalStatus::Rejected),
+    )
+    .await;
+
+    assert_eq!(outcome, VoteOutcome::Rejected);
+}
+
+/// §3.3 full quorum for a rekey means every *ordinary* operator, not every identity on file.
+#[tokio::test]
+async fn unanimous_ordinary_approval_approves_a_rekey_while_recovery_is_awake() {
+    let outcome = settle_vote_with(
+        ProposalKindTag::TriggerRekey,
+        tally(3, 0, 3, 2),
+        /* recovery_active */ true,
+        Some(ProposalStatus::Approved),
+    )
+    .await;
+
+    assert_eq!(outcome, VoteOutcome::Approved);
+}
+
+/// §3.5: recovery operators do not vote on `ApproveSdkClient`, so they must not inflate its
+/// electorate. Before the fix, `total_eligible` counted them anyway (5, not 3), so the
+/// rejection test `reject > total_eligible - threshold` became `3 > 5 - 2 = 3`, which is
+/// false -- three unanimous rejections left the proposal `Pending` forever, since a fourth
+/// vote could never arrive. After the fix, `total_eligible` is 3 and the same test becomes
+/// `3 > 3 - 2 = 1`, which settles it.
+#[tokio::test]
+async fn unanimous_ordinary_rejection_rejects_a_non_full_quorum_proposal_while_recovery_is_awake() {
+    let outcome = settle_vote_with(
+        ProposalKindTag::ApproveSdkClient,
+        tally(0, 3, 3, 2),
+        /* recovery_active */ true,
+        Some(ProposalStatus::Rejected),
+    )
+    .await;
+
+    assert_eq!(outcome, VoteOutcome::Rejected);
+}
+
+/// §3.5/§3.6: `ReplaceOperator` is the one kind recovery may vote on, so it is the only kind
+/// where whether recovery is awake is observable at all -- for every other kind
+/// `narrow_electorate` zeroes `total_recovery` regardless of `is_recovery_active`, short-
+/// circuiting before that call. A sleeping recovery electorate must not raise the bar here:
+/// with 1 ordinary operator and 2 (asleep) recovery operators, the lone ordinary approval
+/// must already reach full quorum.
+#[tokio::test]
+async fn sleeping_recovery_operators_do_not_count_towards_quorum() {
+    let outcome = settle_vote_with(
+        ProposalKindTag::ReplaceOperator,
+        tally(1, 0, 1, 2),
+        /* recovery_active */ false,
+        Some(ProposalStatus::Approved),
+    )
+    .await;
+
+    assert_eq!(outcome, VoteOutcome::Approved);
+}
+
+/// The sequence the whole-branch review worked through, on a `ReplaceOperator` with 3
+/// ordinary and 2 recovery operators (§3.3: full quorum). Both recovery operators approve
+/// while awake; one ordinary operator approves; another ordinary operator then cancels the
+/// wake-up -- `cancel_wakeup` cancels an uncancelled request whether or not its window has
+/// elapsed, so the committee goes straight back to sleep with its votes on the record; a
+/// second ordinary operator approves.
+///
+/// The store now reports 4 approvals, 2 of them from a committee that is no longer eligible.
+/// Narrowing the electorate has to drop those votes along with the voters: what is left is 2
+/// of 3 ordinary approvals, and a full quorum needs all three. Counting the electorate down
+/// to 3 while keeping all 4 votes would replace an operator on two ordinary approvals.
+#[tokio::test]
+async fn recovery_votes_leave_with_the_committee_that_cast_them() {
+    let outcome = settle_vote_with(
+        ProposalKindTag::ReplaceOperator,
+        mixed_tally(
+            /* ordinary_approve */ 2, /* ordinary_reject */ 0,
+            /* recovery_approve */ 2, /* recovery_reject */ 0,
+            /* total_ordinary */ 3, /* total_recovery */ 2,
+        ),
+        /* recovery_active */ false,
+        None,
+    )
+    .await;
+
+    assert_eq!(
+        outcome,
+        VoteOutcome::Pending,
+        "two of three ordinary approvals must not carry a full-quorum proposal, whatever a \
+         sleeping recovery committee voted earlier"
+    );
+}

server/crates/arbiter-server/src/actors/router/mod.rs

@@ -1,79 +0,0 @@
-use std::{
-    collections::{HashMap},
-    ops::ControlFlow,
-};
-
-use kameo::{
-    Actor,
-    actor::{ActorId, ActorRef},
-    messages,
-    prelude::{ActorStopReason, Context, WeakActorRef},
-};
-use tracing::info;
-
-use crate::actors::{client::session::ClientSession, user_agent::session::UserAgentSession};
-
-#[derive(Default)]
-pub struct MessageRouter {
-    pub user_agents: HashMap<ActorId, ActorRef<UserAgentSession>>,
-    pub clients: HashMap<ActorId, ActorRef<ClientSession>>,
-}
-
-impl Actor for MessageRouter {
-    type Args = Self;
-
-    type Error = ();
-
-    async fn on_start(args: Self::Args, _: ActorRef<Self>) -> Result<Self, Self::Error> {
-        Ok(args)
-    }
-
-    async fn on_link_died(
-        &mut self,
-        _: WeakActorRef<Self>,
-        id: ActorId,
-        _: ActorStopReason,
-    ) -> Result<ControlFlow<ActorStopReason>, Self::Error> {
-        if self.user_agents.remove(&id).is_some() {
-            info!(
-                ?id,
-                actor = "MessageRouter",
-                event = "useragent.disconnected"
-            );
-        } else if self.clients.remove(&id).is_some() {
-            info!(?id, actor = "MessageRouter", event = "client.disconnected");
-        } else {
-            info!(
-                ?id,
-                actor = "MessageRouter",
-                event = "unknown.actor.disconnected"
-            );
-        }
-        Ok(ControlFlow::Continue(()))
-    }
-}
-
-#[messages]
-impl MessageRouter {
-    #[message(ctx)]
-    pub async fn register_user_agent(
-        &mut self,
-        actor: ActorRef<UserAgentSession>,
-        ctx: &mut Context<Self, ()>,
-    ) {
-        info!(id = %actor.id(), actor = "MessageRouter", event = "useragent.connected");
-        ctx.actor_ref().link(&actor).await;
-        self.user_agents.insert(actor.id(), actor);
-    }
-
-    #[message(ctx)]
-    pub async fn register_client(
-        &mut self,
-        actor: ActorRef<ClientSession>,
-        ctx: &mut Context<Self, ()>,
-    ) {
-        info!(id = %actor.id(), actor = "MessageRouter", event = "client.connected");
-        ctx.actor_ref().link(&actor).await;
-        self.clients.insert(actor.id(), actor);
-    }
-}

server/crates/arbiter-server/src/actors/user_agent/auth.rs

@@ -1,118 +0,0 @@
-use arbiter_proto::proto::user_agent::{
-    AuthChallengeRequest, AuthChallengeSolution, UserAgentRequest,
-    user_agent_request::Payload as UserAgentRequestPayload,
-};
-use ed25519_dalek::VerifyingKey;
-use tracing::error;
-
-use crate::actors::user_agent::{
-    UserAgentConnection,
-    auth::state::{AuthContext, AuthStateMachine}, session::UserAgentSession,
-};
-
-#[derive(thiserror::Error, Debug, PartialEq)]
-pub enum Error {
-    #[error("Unexpected message payload")]
-    UnexpectedMessagePayload,
-    #[error("Invalid client public key length")]
-    InvalidClientPubkeyLength,
-    #[error("Invalid client public key encoding")]
-    InvalidAuthPubkeyEncoding,
-    #[error("Database pool unavailable")]
-    DatabasePoolUnavailable,
-    #[error("Database operation failed")]
-    DatabaseOperationFailed,
-    #[error("Public key not registered")]
-    PublicKeyNotRegistered,
-    #[error("Transport error")]
-    Transport,
-    #[error("Invalid bootstrap token")]
-    InvalidBootstrapToken,
-    #[error("Bootstrapper actor unreachable")]
-    BootstrapperActorUnreachable,
-    #[error("Invalid challenge solution")]
-    InvalidChallengeSolution,
-}
-
-mod state;
-use state::*;
-
-fn parse_auth_event(payload: UserAgentRequestPayload) -> Result<AuthEvents, Error> {
-    match payload {
-        UserAgentRequestPayload::AuthChallengeRequest(AuthChallengeRequest {
-            pubkey,
-            bootstrap_token: None,
-        }) => {
-            let pubkey_bytes = pubkey.as_array().ok_or(Error::InvalidClientPubkeyLength)?;
-            let pubkey = VerifyingKey::from_bytes(pubkey_bytes)
-                .map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
-            Ok(AuthEvents::AuthRequest(ChallengeRequest {
-                pubkey: pubkey.into(),
-            }))
-        }
-        UserAgentRequestPayload::AuthChallengeRequest(AuthChallengeRequest {
-            pubkey,
-            bootstrap_token: Some(token),
-        }) => {
-            let pubkey_bytes = pubkey.as_array().ok_or(Error::InvalidClientPubkeyLength)?;
-            let pubkey = VerifyingKey::from_bytes(pubkey_bytes)
-                .map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
-            Ok(AuthEvents::BootstrapAuthRequest(BootstrapAuthRequest {
-                pubkey: pubkey.into(),
-                token,
-            }))
-        }
-        UserAgentRequestPayload::AuthChallengeSolution(AuthChallengeSolution { signature }) => {
-            Ok(AuthEvents::ReceivedSolution(ChallengeSolution {
-                solution: signature,
-            }))
-        }
-        _ => Err(Error::UnexpectedMessagePayload),
-    }
-}
-
-pub async fn authenticate(props: &mut UserAgentConnection) -> Result<VerifyingKey, Error> {
-    let mut state = AuthStateMachine::new(AuthContext::new(props));
-
-    loop {
-        // This is needed because `state` now holds mutable reference to `ConnectionProps`, so we can't directly access `props` here
-        let transport = state.context_mut().conn.transport.as_mut();
-        let Some(UserAgentRequest {
-            payload: Some(payload),
-        }) = transport.recv().await
-        else {
-            return Err(Error::Transport);
-        };
-
-        let event = parse_auth_event(payload)?;
-
-        match state.process_event(event).await {
-            Ok(AuthStates::AuthOk(key)) => return Ok(key.clone()),
-            Err(AuthError::ActionFailed(err)) => {
-                error!(?err, "State machine action failed");
-                return Err(err);
-            }
-            Err(AuthError::GuardFailed(err)) => {
-                error!(?err, "State machine guard failed");
-                return Err(err);
-            }
-            Err(AuthError::InvalidEvent) => {
-                error!("Invalid event for current state");
-                return Err(Error::InvalidChallengeSolution);
-            }
-            Err(AuthError::TransitionsFailed) => {
-                error!("Invalid state transition");
-                return Err(Error::InvalidChallengeSolution);
-            }
-
-            _ => (),
-        }
-    }
-}
-
-
-pub async fn authenticate_and_create(mut props: UserAgentConnection) -> Result<UserAgentSession, Error> {
-    let key = authenticate(&mut props).await?;
-    let session = UserAgentSession::new(props, key.clone());
-    Ok(session)
-}

server/crates/arbiter-server/src/actors/user_agent/auth/state.rs

@@ -1,202 +0,0 @@
-use arbiter_proto::proto::user_agent::{
-    AuthChallenge, UserAgentResponse,
-    user_agent_response::Payload as UserAgentResponsePayload,
-};
-use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl, update};
-use diesel_async::RunQueryDsl;
-use ed25519_dalek::VerifyingKey;
-use tracing::error;
-
-use super::Error;
-use crate::{
-    actors::{bootstrap::ConsumeToken, user_agent::UserAgentConnection},
-    db::schema,
-};
-
-pub struct ChallengeRequest {
-    pub pubkey: VerifyingKey,
-}
-
-pub struct BootstrapAuthRequest {
-    pub pubkey: VerifyingKey,
-    pub token: String,
-}
-
-pub struct ChallengeContext {
-    pub challenge: AuthChallenge,
-    pub key: VerifyingKey,
-}
-
-pub struct ChallengeSolution {
-    pub solution: Vec<u8>,
-}
-
-smlang::statemachine!(
-    name: Auth,
-    custom_error: true,
-    transitions: {
-        *Init + AuthRequest(ChallengeRequest) / async prepare_challenge = SentChallenge(ChallengeContext),
-        Init + BootstrapAuthRequest(BootstrapAuthRequest) [async verify_bootstrap_token] / provide_key_bootstrap = AuthOk(VerifyingKey),
-        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) [async verify_solution] / provide_key = AuthOk(VerifyingKey),
-    }
-);
-
-async fn create_nonce(db: &crate::db::DatabasePool, pubkey_bytes: &[u8]) -> Result<i32, Error> {
-    let mut db_conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::DatabasePoolUnavailable
-    })?;
-    db_conn
-        .exclusive_transaction(|conn| {
-            Box::pin(async move {
-                let current_nonce = schema::useragent_client::table
-                    .filter(schema::useragent_client::public_key.eq(pubkey_bytes.to_vec()))
-                    .select(schema::useragent_client::nonce)
-                    .first::<i32>(conn)
-                    .await?;
-
-                update(schema::useragent_client::table)
-                    .filter(schema::useragent_client::public_key.eq(pubkey_bytes.to_vec()))
-                    .set(schema::useragent_client::nonce.eq(current_nonce + 1))
-                    .execute(conn)
-                    .await?;
-
-                Result::<_, diesel::result::Error>::Ok(current_nonce)
-            })
-        })
-        .await
-        .optional()
-        .map_err(|e| {
-            error!(error = ?e, "Database error");
-            Error::DatabaseOperationFailed
-        })?
-        .ok_or_else(|| {
-            error!(?pubkey_bytes, "Public key not found in database");
-            Error::PublicKeyNotRegistered
-        })
-}
-
-async fn register_key(db: &crate::db::DatabasePool, pubkey_bytes: &[u8]) -> Result<(), Error> {
-    let mut conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::DatabasePoolUnavailable
-    })?;
-
-    diesel::insert_into(schema::useragent_client::table)
-        .values((
-            schema::useragent_client::public_key.eq(pubkey_bytes.to_vec()),
-            schema::useragent_client::nonce.eq(1),
-        ))
-        .execute(&mut conn)
-        .await
-        .map_err(|e| {
-            error!(error = ?e, "Database error");
-            Error::DatabaseOperationFailed
-        })?;
-
-    Ok(())
-}
-
-pub struct AuthContext<'a> {
-    pub(super) conn: &'a mut UserAgentConnection,
-}
-
-impl<'a> AuthContext<'a> {
-    pub fn new(conn: &'a mut UserAgentConnection) -> Self {
-        Self { conn }
-    }
-}
-
-impl AuthStateMachineContext for AuthContext<'_> {
-    type Error = Error;
-
-    async fn verify_solution(
-        &self,
-        ChallengeContext { challenge, key }: &ChallengeContext,
-        ChallengeSolution { solution }: &ChallengeSolution,
-    ) -> Result<bool, Self::Error> {
-        let formatted_challenge =
-            arbiter_proto::format_challenge(challenge.nonce, &challenge.pubkey);
-
-        let signature = solution.as_slice().try_into().map_err(|_| {
-            error!(?solution, "Invalid signature length");
-            Error::InvalidChallengeSolution
-        })?;
-
-        let valid = key.verify_strict(&formatted_challenge, &signature).is_ok();
-
-        Ok(valid)
-    }
-
-    async fn prepare_challenge(
-        &mut self,
-        ChallengeRequest { pubkey }: ChallengeRequest,
-    ) -> Result<ChallengeContext, Self::Error> {
-        let nonce = create_nonce(&self.conn.db, pubkey.as_bytes()).await?;
-
-        let challenge = AuthChallenge {
-            pubkey: pubkey.as_bytes().to_vec(),
-            nonce,
-        };
-
-        self.conn
-            .transport
-            .send(Ok(UserAgentResponse {
-                payload: Some(UserAgentResponsePayload::AuthChallenge(challenge.clone())),
-            }))
-            .await
-            .map_err(|e| {
-                error!(?e, "Failed to send auth challenge");
-                Error::Transport
-            })?;
-
-        Ok(ChallengeContext {
-            challenge,
-            key: pubkey,
-        })
-    }
-
-    #[allow(missing_docs)]
-    #[allow(clippy::result_unit_err)]
-    async fn verify_bootstrap_token(
-        &self,
-        BootstrapAuthRequest { pubkey, token }: &BootstrapAuthRequest,
-    ) -> Result<bool, Self::Error> {
-        let token_ok: bool = self
-            .conn
-            .actors
-            .bootstrapper
-            .ask(ConsumeToken {
-                token: token.clone(),
-            })
-            .await
-            .map_err(|e| {
-                error!(?pubkey, "Failed to consume bootstrap token: {e}");
-                Error::BootstrapperActorUnreachable
-            })?;
-
-        if !token_ok {
-            error!(?pubkey, "Invalid bootstrap token provided");
-            return Err(Error::InvalidBootstrapToken);
-        }
-
-        register_key(&self.conn.db, pubkey.as_bytes()).await?;
-
-        Ok(true)
-    }
-
-    fn provide_key_bootstrap(
-        &mut self,
-        event_data: BootstrapAuthRequest,
-    ) -> Result<VerifyingKey, Self::Error> {
-        Ok(event_data.pubkey)
-    }
-
-    fn provide_key(
-        &mut self,
-        state_data: &ChallengeContext,
-        _: ChallengeSolution,
-    ) -> Result<VerifyingKey, Self::Error> {
-        Ok(state_data.key)
-    }
-}

server/crates/arbiter-server/src/actors/user_agent/mod.rs

@@ -1,65 +0,0 @@
-use arbiter_proto::{
-    proto::user_agent::{UserAgentRequest, UserAgentResponse},
-    transport::Bi,
-};
-use kameo::actor::Spawn as _;
-use tracing::{error, info};
-
-use crate::{
-    actors::{GlobalActors, user_agent::session::UserAgentSession},
-    db::{self},
-};
-
-#[derive(Debug, thiserror::Error, PartialEq)]
-pub enum UserAgentError {
-    #[error("Expected message with payload")]
-    MissingRequestPayload,
-    #[error("Unexpected request payload")]
-    UnexpectedRequestPayload,
-    #[error("Invalid state for unseal encrypted key")]
-    InvalidStateForUnsealEncryptedKey,
-    #[error("client_pubkey must be 32 bytes")]
-    InvalidClientPubkeyLength,
-    #[error("State machine error")]
-    StateTransitionFailed,
-    #[error("Vault is not available")]
-    KeyHolderActorUnreachable,
-    #[error(transparent)]
-    Auth(#[from] auth::Error),
-    #[error("Failed registering connection")]
-    ConnectionRegistrationFailed,
-}
-
-pub type Transport =
-    Box<dyn Bi<UserAgentRequest, Result<UserAgentResponse, UserAgentError>> + Send>;
-
-pub struct UserAgentConnection {
-    db: db::DatabasePool,
-    actors: GlobalActors,
-    transport: Transport,
-}
-
-impl UserAgentConnection {
-    pub fn new(db: db::DatabasePool, actors: GlobalActors, transport: Transport) -> Self {
-        Self {
-            db,
-            actors,
-            transport,
-        }
-    }
-}
-
-pub mod auth;
-pub mod session;
-
-pub async fn connect_user_agent(props: UserAgentConnection) {
-    match auth::authenticate_and_create(props).await {
-        Ok(session) => {
-            UserAgentSession::spawn(session);
-            info!("User authenticated, session started");
-        }
-        Err(err) => {
-            error!(?err, "Authentication failed, closing connection");
-        }
-    }
-}

server/crates/arbiter-server/src/actors/user_agent/session.rs

@@ -1,320 +0,0 @@
-use std::{ops::DerefMut, sync::Mutex};
-
-use arbiter_proto::proto::{
-    evm as evm_proto,
-    user_agent::{
-        UnsealEncryptedKey, UnsealResult, UnsealStart, UnsealStartResponse, UserAgentRequest,
-        UserAgentResponse, user_agent_request::Payload as UserAgentRequestPayload,
-        user_agent_response::Payload as UserAgentResponsePayload,
-    },
-};
-use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
-use ed25519_dalek::VerifyingKey;
-use kameo::{
-    Actor,
-    error::SendError,
-};
-use memsafe::MemSafe;
-use tokio::select;
-use tracing::{error, info};
-use x25519_dalek::{EphemeralSecret, PublicKey};
-
-use crate::actors::{
-    evm::{Generate, ListWallets},
-    keyholder::{self, TryUnseal},
-    router::RegisterUserAgent,
-    user_agent::{UserAgentConnection, UserAgentError},
-};
-
-mod state;
-use state::{DummyContext, UnsealContext, UserAgentEvents, UserAgentStateMachine, UserAgentStates};
-
-pub struct UserAgentSession {
-    props: UserAgentConnection,
-    key: VerifyingKey,
-    state: UserAgentStateMachine<DummyContext>,
-}
-
-impl UserAgentSession {
-    pub(crate) fn new(props: UserAgentConnection, key: VerifyingKey) -> Self {
-        Self {
-            props,
-            key,
-            state: UserAgentStateMachine::new(DummyContext),
-        }
-    }
-
-    fn transition(&mut self, event: UserAgentEvents) -> Result<(), UserAgentError> {
-        self.state.process_event(event).map_err(|e| {
-            error!(?e, "State transition failed");
-            UserAgentError::StateTransitionFailed
-        })?;
-        Ok(())
-    }
-
-    pub async fn process_transport_inbound(&mut self, req: UserAgentRequest) -> Output {
-        let msg = req.payload.ok_or_else(|| {
-            error!(actor = "useragent", "Received message with no payload");
-            UserAgentError::MissingRequestPayload
-        })?;
-
-        match msg {
-            UserAgentRequestPayload::UnsealStart(unseal_start) => {
-                self.handle_unseal_request(unseal_start).await
-            }
-            UserAgentRequestPayload::UnsealEncryptedKey(unseal_encrypted_key) => {
-                self.handle_unseal_encrypted_key(unseal_encrypted_key).await
-            }
-            UserAgentRequestPayload::EvmWalletCreate(_) => self.handle_evm_wallet_create().await,
-            UserAgentRequestPayload::EvmWalletList(_) => self.handle_evm_wallet_list().await,
-            _ => Err(UserAgentError::UnexpectedRequestPayload),
-        }
-    }
-}
-
-type Output = Result<UserAgentResponse, UserAgentError>;
-
-fn response(payload: UserAgentResponsePayload) -> UserAgentResponse {
-    UserAgentResponse {
-        payload: Some(payload),
-    }
-}
-
-impl UserAgentSession {
-    async fn handle_unseal_request(&mut self, req: UnsealStart) -> Output {
-        let secret = EphemeralSecret::random();
-        let public_key = PublicKey::from(&secret);
-
-        let client_pubkey_bytes: [u8; 32] = req
-            .client_pubkey
-            .try_into()
-            .map_err(|_| UserAgentError::InvalidClientPubkeyLength)?;
-
-        let client_public_key = PublicKey::from(client_pubkey_bytes);
-
-        self.transition(UserAgentEvents::UnsealRequest(UnsealContext {
-            secret: Mutex::new(Some(secret)),
-            client_public_key,
-        }))?;
-
-        Ok(response(UserAgentResponsePayload::UnsealStartResponse(
-            UnsealStartResponse {
-                server_pubkey: public_key.as_bytes().to_vec(),
-            },
-        )))
-    }
-
-    async fn handle_unseal_encrypted_key(&mut self, req: UnsealEncryptedKey) -> Output {
-        let UserAgentStates::WaitingForUnsealKey(unseal_context) = self.state.state() else {
-            error!("Received unseal encrypted key in invalid state");
-            return Err(UserAgentError::InvalidStateForUnsealEncryptedKey);
-        };
-        let ephemeral_secret = {
-            let mut secret_lock = unseal_context.secret.lock().unwrap();
-            let secret = secret_lock.take();
-            match secret {
-                Some(secret) => secret,
-                None => {
-                    drop(secret_lock);
-                    error!("Ephemeral secret already taken");
-                    self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                    return Ok(response(UserAgentResponsePayload::UnsealResult(
-                        UnsealResult::InvalidKey.into(),
-                    )));
-                }
-            }
-        };
-
-        let nonce = XNonce::from_slice(&req.nonce);
-
-        let shared_secret = ephemeral_secret.diffie_hellman(&unseal_context.client_public_key);
-        let cipher = XChaCha20Poly1305::new(shared_secret.as_bytes().into());
-
-        let mut seal_key_buffer = MemSafe::new(req.ciphertext.clone()).unwrap();
-
-        let decryption_result = {
-            let mut write_handle = seal_key_buffer.write().unwrap();
-            let write_handle = write_handle.deref_mut();
-            cipher.decrypt_in_place(nonce, &req.associated_data, write_handle)
-        };
-
-        match decryption_result {
-            Ok(_) => {
-                match self
-                    .props
-                    .actors
-                    .key_holder
-                    .ask(TryUnseal {
-                        seal_key_raw: seal_key_buffer,
-                    })
-                    .await
-                {
-                    Ok(_) => {
-                        info!("Successfully unsealed key with client-provided key");
-                        self.transition(UserAgentEvents::ReceivedValidKey)?;
-                        Ok(response(UserAgentResponsePayload::UnsealResult(
-                            UnsealResult::Success.into(),
-                        )))
-                    }
-                    Err(SendError::HandlerError(keyholder::Error::InvalidKey)) => {
-                        self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                        Ok(response(UserAgentResponsePayload::UnsealResult(
-                            UnsealResult::InvalidKey.into(),
-                        )))
-                    }
-                    Err(SendError::HandlerError(err)) => {
-                        error!(?err, "Keyholder failed to unseal key");
-                        self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                        Ok(response(UserAgentResponsePayload::UnsealResult(
-                            UnsealResult::InvalidKey.into(),
-                        )))
-                    }
-                    Err(err) => {
-                        error!(?err, "Failed to send unseal request to keyholder");
-                        self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                        Err(UserAgentError::KeyHolderActorUnreachable)
-                    }
-                }
-            }
-            Err(err) => {
-                error!(?err, "Failed to decrypt unseal key");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Ok(response(UserAgentResponsePayload::UnsealResult(
-                    UnsealResult::InvalidKey.into(),
-                )))
-            }
-        }
-    }
-}
-
-impl UserAgentSession {
-    async fn handle_evm_wallet_create(&mut self) -> Output {
-        use evm_proto::wallet_create_response::Result as CreateResult;
-
-        let result = match self.props.actors.evm.ask(Generate {}).await {
-            Ok(address) => CreateResult::Wallet(evm_proto::WalletEntry {
-                address: address.as_slice().to_vec(),
-            }),
-            Err(err) => CreateResult::Error(map_evm_error("wallet create", err).into()),
-        };
-
-        Ok(response(UserAgentResponsePayload::EvmWalletCreate(
-            evm_proto::WalletCreateResponse {
-                result: Some(result),
-            },
-        )))
-    }
-
-    async fn handle_evm_wallet_list(&mut self) -> Output {
-        use evm_proto::wallet_list_response::Result as ListResult;
-
-        let result = match self.props.actors.evm.ask(ListWallets {}).await {
-            Ok(wallets) => ListResult::Wallets(evm_proto::WalletList {
-                wallets: wallets
-                    .into_iter()
-                    .map(|addr| evm_proto::WalletEntry {
-                        address: addr.as_slice().to_vec(),
-                    })
-                    .collect(),
-            }),
-            Err(err) => ListResult::Error(map_evm_error("wallet list", err).into()),
-        };
-
-        Ok(response(UserAgentResponsePayload::EvmWalletList(
-            evm_proto::WalletListResponse {
-                result: Some(result),
-            },
-        )))
-    }
-}
-
-fn map_evm_error<M>(op: &str, err: SendError<M, crate::actors::evm::Error>) -> evm_proto::EvmError {
-    use crate::actors::{evm::Error as EvmError, keyholder::Error as KhError};
-    match err {
-        SendError::HandlerError(EvmError::Keyholder(KhError::NotBootstrapped)) => {
-            evm_proto::EvmError::VaultSealed
-        }
-        SendError::HandlerError(err) => {
-            error!(?err, "EVM {op} failed");
-            evm_proto::EvmError::Internal
-        }
-        _ => {
-            error!("EVM actor unreachable during {op}");
-            evm_proto::EvmError::Internal
-        }
-    }
-}
-
-impl Actor for UserAgentSession {
-    type Args = Self;
-
-    type Error = UserAgentError;
-
-    async fn on_start(
-        args: Self::Args,
-        this: kameo::prelude::ActorRef<Self>,
-    ) -> Result<Self, Self::Error> {
-        args.props
-            .actors
-            .router
-            .ask(RegisterUserAgent {
-                actor: this.clone(),
-            })
-            .await
-            .map_err(|err| {
-                error!(?err, "Failed to register user agent connection with router");
-                UserAgentError::ConnectionRegistrationFailed
-            })?;
-        Ok(args)
-    }
-
-    async fn next(
-        &mut self,
-        _actor_ref: kameo::prelude::WeakActorRef<Self>,
-        mailbox_rx: &mut kameo::prelude::MailboxReceiver<Self>,
-    ) -> Option<kameo::mailbox::Signal<Self>> {
-        loop {
-            select! {
-                signal = mailbox_rx.recv() => {
-                    return signal;
-                }
-                msg = self.props.transport.recv() => {
-                    match msg {
-                        Some(request) => {
-                            match self.process_transport_inbound(request).await {
-                                Ok(response) => {
-                                    if self.props.transport.send(Ok(response)).await.is_err() {
-                                        error!(actor = "useragent", reason = "channel closed", "send.failed");
-                                        return Some(kameo::mailbox::Signal::Stop);
-                                    }
-                                }
-                                Err(err) => {
-                                    let _ = self.props.transport.send(Err(err)).await;
-                                    return Some(kameo::mailbox::Signal::Stop);
-                                }
-                            }
-                        }
-                        None => {
-                            info!(actor = "useragent", "transport.closed");
-                            return Some(kameo::mailbox::Signal::Stop);
-                        }
-                    }
-                }
-            }
-        }
-    }
-}
-
-impl UserAgentSession {
-    pub fn new_test(db: crate::db::DatabasePool, actors: crate::actors::GlobalActors) -> Self {
-        use arbiter_proto::transport::DummyTransport;
-        let transport: super::Transport = Box::new(DummyTransport::new());
-        let props = UserAgentConnection::new(db, actors, transport);
-        let key = VerifyingKey::from_bytes(&[0u8; 32]).unwrap();
-        Self {
-            props,
-            key,
-            state: UserAgentStateMachine::new(DummyContext),
-        }
-    }
-}

server/crates/arbiter-server/src/actors/user_agent/session/state.rs

@@ -1,27 +0,0 @@
-use std::sync::Mutex;
-
-use x25519_dalek::{EphemeralSecret, PublicKey};
-
-pub struct UnsealContext {
-    pub client_public_key: PublicKey,
-    pub secret: Mutex<Option<EphemeralSecret>>,
-}
-
-smlang::statemachine!(
-    name: UserAgent,
-    custom_error: false,
-    transitions: {
-        *Idle + UnsealRequest(UnsealContext) / generate_temp_keypair = WaitingForUnsealKey(UnsealContext),
-        WaitingForUnsealKey(UnsealContext) + ReceivedValidKey = Unsealed,
-        WaitingForUnsealKey(UnsealContext) + ReceivedInvalidKey = Idle,
-    }
-);
-
-pub struct DummyContext;
-impl UserAgentStateMachineContext for DummyContext {
-    #[allow(missing_docs)]
-    #[allow(clippy::unused_unit)]
-    fn generate_temp_keypair(&mut self, event_data: UnsealContext) -> Result<UnsealContext, ()> {
-        Ok(event_data)
-    }
-}

server/crates/arbiter-server/src/actors/vault/mod.rs

@@ -0,0 +1,673 @@
+use crate::{
+    actors::proposal_manager::events::ProposalApproved,
+    crypto::{
+        KeyCell,
+        encryption::v1::{self, Nonce},
+        integrity::{self, v1::HmacSha256},
+    },
+    db::{
+        self,
+        models::{self, RootKeyHistory, RootKeyHistoryId},
+        proposal::ProposalKind,
+        schema,
+    },
+};
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+
+use chrono::Utc;
+use diesel::{
+    ExpressionMethods as _, OptionalExtension, QueryDsl, SelectableHelper,
+    dsl::{insert_into, update},
+};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use hmac::{KeyInit as _, Mac as _};
+use kameo::{Actor, Reply, actor::ActorRef, messages, prelude::Message};
+use kameo_actors::message_bus::{MessageBus, Publish};
+use strum::{EnumDiscriminants, IntoDiscriminant};
+use tracing::{error, info};
+
+pub mod events {
+    #[derive(Clone, Copy)]
+    pub struct Bootstrapped;
+
+    #[derive(Clone, Copy)]
+    pub struct Unsealed;
+
+    #[derive(Clone, Copy)]
+    pub struct VaultResealed;
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("Vault is already bootstrapped")]
+    AlreadyBootstrapped,
+    #[error("Vault is not bootstrapped")]
+    NotBootstrapped,
+    #[error("Vault is sealed")]
+    Sealed,
+    #[error("Invalid key provided")]
+    InvalidKey,
+
+    #[error("Requested aead entry not found")]
+    NotFound,
+
+    #[error("Encryption error: {0}")]
+    Encryption(#[from] chacha20poly1305::aead::Error),
+
+    #[error("Database error: {0}")]
+    DatabaseConnection(#[from] db::PoolError),
+
+    #[error("Database transaction error: {0}")]
+    DatabaseTransaction(#[from] diesel::result::Error),
+
+    #[error("Broken database")]
+    BrokenDatabase,
+}
+
+struct Unsealed {
+    root_key_history_id: RootKeyHistoryId,
+    root_key: KeyCell,
+}
+
+#[derive(Default, EnumDiscriminants)]
+#[strum_discriminants(derive(Reply), vis(pub), name(VaultState))]
+enum State {
+    #[default]
+    Unbootstrapped,
+
+    Sealed {
+        root_key_history_id: RootKeyHistoryId,
+    },
+    Unsealed(Unsealed),
+}
+
+/// Manages vault root key and tracks current state of the vault (bootstrapped/unbootstrapped, sealed/unsealed).
+///
+/// Provides API for encrypting and decrypting data using the vault root key.
+/// Abstraction over database to make sure nonces are never reused and encryption keys are never exposed in plaintext outside of this actor.
+#[derive(Actor)]
+pub struct Vault {
+    db: db::DatabasePool,
+    state: State,
+    events: ActorRef<MessageBus>,
+}
+
+impl Vault {
+    pub async fn new(db: db::DatabasePool, events: ActorRef<MessageBus>) -> Result<Self, Error> {
+        let state = {
+            let mut conn = db.get().await?;
+
+            let (root_key_history,) = schema::arbiter_settings::table
+                .left_join(schema::root_key_history::table)
+                .select((Option::<RootKeyHistory>::as_select(),))
+                .get_result::<(Option<RootKeyHistory>,)>(&mut conn)
+                .await?;
+
+            match root_key_history {
+                Some(root_key_history) => State::Sealed {
+                    root_key_history_id: root_key_history.id,
+                },
+                None => State::Unbootstrapped,
+            }
+        };
+
+        Ok(Self { db, state, events })
+    }
+
+    // Exclusive transaction to avoid race conditions if multiple vaults write
+    // additional layer of protection against nonce-reuse
+    async fn get_new_nonce(
+        pool: &db::DatabasePool,
+        root_key_id: RootKeyHistoryId,
+    ) -> Result<Nonce, Error> {
+        let mut conn = pool.get().await?;
+
+        let nonce = conn
+            .exclusive_transaction(async |conn| {
+                let current_nonce: Vec<u8> = schema::root_key_history::table
+                    .filter(schema::root_key_history::id.eq(root_key_id))
+                    .select(schema::root_key_history::data_encryption_nonce)
+                    .first(&mut *conn)
+                    .await?;
+
+                let mut nonce = Nonce::try_from(current_nonce.as_slice()).map_err(|()| {
+                    error!(
+                        "Broken database: invalid nonce for root key history id={:#?}",
+                        root_key_id
+                    );
+                    Error::BrokenDatabase
+                })?;
+                nonce.increment();
+
+                update(schema::root_key_history::table)
+                    .filter(schema::root_key_history::id.eq(root_key_id))
+                    .set(schema::root_key_history::data_encryption_nonce.eq(nonce.to_vec()))
+                    .execute(&mut *conn)
+                    .await?;
+
+                Result::<_, Error>::Ok(nonce)
+            })
+            .await?;
+
+        Ok(nonce)
+    }
+
+    const fn expect_unsealed(state: &mut State) -> Result<&mut Unsealed, Error> {
+        match state {
+            State::Unsealed(unsealed) => Ok(unsealed),
+            State::Unbootstrapped => Err(Error::NotBootstrapped),
+            State::Sealed { .. } => Err(Error::Sealed),
+        }
+    }
+}
+
+#[messages]
+impl Vault {
+    #[message]
+    pub async fn bootstrap(&mut self, mut seal_key: KeyCell) -> Result<(), Error> {
+        if !matches!(&self.state, State::Unbootstrapped) {
+            return Err(Error::AlreadyBootstrapped);
+        }
+
+        let mut root_key = KeyCell::new_secure_random();
+
+        // Zero nonces are fine because they are one-time
+        let root_key_nonce = Nonce::default();
+        let data_encryption_nonce = Nonce::default();
+
+        // Generate salt (kept for schema compat)
+        let root_key_salt = v1::generate_salt();
+
+        let root_key_ciphertext: Vec<u8> = root_key.0.read_inline(|rk| {
+            seal_key
+                .encrypt(&root_key_nonce, v1::ROOT_KEY_TAG, rk.as_slice())
+                .map_err(|err| {
+                    error!(?err, "Fatal bootstrap error");
+                    Error::Encryption(err)
+                })
+        })?;
+
+        let data_encryption_nonce_bytes = data_encryption_nonce.to_vec();
+        let mut conn = self.db.get().await?;
+
+        let root_key_history_id = conn
+            .transaction(async |conn| {
+                let root_key_history_id = insert_into(schema::root_key_history::table)
+                    .values(&models::NewRootKeyHistory {
+                        ciphertext: root_key_ciphertext.clone(),
+                        tag: v1::ROOT_KEY_TAG.to_vec(),
+                        root_key_encryption_nonce: root_key_nonce.to_vec(),
+                        data_encryption_nonce: data_encryption_nonce_bytes.clone(),
+                        schema_version: 1,
+                        salt: root_key_salt.to_vec(),
+                    })
+                    .returning(schema::root_key_history::id)
+                    .get_result(&mut *conn)
+                    .await?;
+
+                update(schema::arbiter_settings::table)
+                    .set(schema::arbiter_settings::root_key_id.eq(root_key_history_id))
+                    .execute(&mut *conn)
+                    .await?;
+
+                Result::<_, diesel::result::Error>::Ok(RootKeyHistoryId::from_raw(
+                    root_key_history_id,
+                ))
+            })
+            .await?;
+
+        self.state = State::Unsealed(Unsealed {
+            root_key,
+            root_key_history_id,
+        });
+
+        info!("Vault bootstrapped successfully");
+        if let Err(err) = self.events.tell(Publish(events::Bootstrapped)).await {
+            error!(?err, "Failed to publish Bootstrapped event");
+        }
+
+        Ok(())
+    }
+
+    #[message]
+    pub async fn try_unseal(&mut self, mut seal_key: KeyCell) -> Result<(), Error> {
+        let State::Sealed {
+            root_key_history_id,
+        } = &self.state
+        else {
+            return Err(Error::NotBootstrapped);
+        };
+        let root_key_history_id = *root_key_history_id;
+
+        // We don't want to hold connection while doing expensive work
+        let current_key = {
+            let mut conn = self.db.get().await?;
+            schema::root_key_history::table
+                .filter(schema::root_key_history::id.eq(root_key_history_id))
+                .select(RootKeyHistory::as_select())
+                .first(&mut conn)
+                .await?
+        };
+
+        let nonce =
+            Nonce::try_from(current_key.root_key_encryption_nonce.as_slice()).map_err(|()| {
+                error!("Broken database: invalid nonce for root key");
+                Error::BrokenDatabase
+            })?;
+
+        let mut root_key_bytes = SafeCell::new(current_key.ciphertext.clone());
+        seal_key
+            .decrypt_in_place(&nonce, v1::ROOT_KEY_TAG, &mut root_key_bytes)
+            .map_err(|err| {
+                error!(?err, "Failed to unseal root key: invalid seal key");
+                Error::InvalidKey
+            })?;
+
+        let root_key = KeyCell::try_from(root_key_bytes).map_err(|()| {
+            error!("Broken database: invalid encryption key size");
+            Error::BrokenDatabase
+        })?;
+
+        self.state = State::Unsealed(Unsealed {
+            root_key_history_id: current_key.id,
+            root_key,
+        });
+
+        info!("Vault unsealed successfully");
+        let _ = self.events.tell(Publish(events::Unsealed)).await;
+
+        Ok(())
+    }
+
+    /// Re-encrypts the root key with `new_seal_key`, updating its `root_key_history` row in
+    /// place. Called after a Shamir re-key, so the old seal key is no longer sufficient to
+    /// unseal. The root key itself does not change, so its row identity (and the nonce counter
+    /// and integrity envelopes bound to it) must not change either.
+    #[message]
+    pub async fn rekey_root_key(&mut self, mut new_seal_key: KeyCell) -> Result<(), Error> {
+        let Unsealed {
+            root_key,
+            root_key_history_id,
+        } = Self::expect_unsealed(&mut self.state)?;
+
+        let new_nonce = Nonce::default();
+        let new_salt = v1::generate_salt();
+
+        let new_ciphertext: Vec<u8> = root_key.0.read_inline(|rk| {
+            new_seal_key
+                .encrypt(&new_nonce, v1::ROOT_KEY_TAG, rk.as_slice())
+                .map_err(|err| {
+                    error!(?err, "Fatal rekey error");
+                    Error::Encryption(err)
+                })
+        })?;
+
+        let mut conn = self.db.get().await?;
+
+        // The root key is unchanged, so its row keeps its identity: `data_encryption_nonce`
+        // keeps counting up, and every integrity envelope stays bound to the same key version.
+        // Only the seal-key material is replaced, retiring the previous one. `tag` and
+        // `schema_version` are deliberately left untouched: the seal-key encryption scheme
+        // itself is unchanged by a re-key, so there is nothing new for them to describe.
+        let rows_updated = update(schema::root_key_history::table)
+            .filter(schema::root_key_history::id.eq(*root_key_history_id))
+            .set((
+                schema::root_key_history::ciphertext.eq(new_ciphertext),
+                schema::root_key_history::root_key_encryption_nonce.eq(new_nonce.to_vec()),
+                schema::root_key_history::salt.eq(new_salt.to_vec()),
+            ))
+            .execute(&mut conn)
+            .await?;
+
+        if rows_updated == 0 {
+            error!(
+                "Broken database: rekey matched no root_key_history row id={:#?}",
+                root_key_history_id
+            );
+            return Err(Error::BrokenDatabase);
+        }
+
+        info!("Vault root key rekeyed successfully");
+        Ok(())
+    }
+
+    #[message]
+    pub async fn seal(&mut self) -> Result<(), Error> {
+        let Unsealed {
+            root_key_history_id,
+            ..
+        } = Self::expect_unsealed(&mut self.state)?;
+
+        self.state = State::Sealed {
+            root_key_history_id: *root_key_history_id,
+        };
+        let _ = self.events.tell(Publish(events::VaultResealed)).await;
+        Ok(())
+    }
+}
+
+// Server-side cryptographic operations
+#[messages]
+impl Vault {
+    #[message]
+    pub async fn decrypt(&mut self, aead_id: i32) -> Result<SafeCell<Vec<u8>>, Error> {
+        let Unsealed { root_key, .. } = Self::expect_unsealed(&mut self.state)?;
+
+        let row: models::AeadEncrypted = {
+            let mut conn = self.db.get().await?;
+            schema::aead_encrypted::table
+                .select(models::AeadEncrypted::as_select())
+                .filter(schema::aead_encrypted::id.eq(aead_id))
+                .first(&mut conn)
+                .await
+                .optional()?
+                .ok_or(Error::NotFound)?
+        };
+
+        let nonce = Nonce::try_from(row.current_nonce.as_slice()).map_err(|()| {
+            error!(
+                "Broken database: invalid nonce for aead_encrypted id={}",
+                aead_id
+            );
+            Error::BrokenDatabase
+        })?;
+        let mut output = SafeCell::new(row.ciphertext);
+        root_key.decrypt_in_place(&nonce, v1::TAG, &mut output)?;
+        Ok(output)
+    }
+
+    // Creates new `aead_encrypted` entry in the database and returns it's ID
+    #[message]
+    pub async fn create_new(&mut self, mut plaintext: SafeCell<Vec<u8>>) -> Result<i32, Error> {
+        let Unsealed {
+            root_key,
+            root_key_history_id,
+        } = Self::expect_unsealed(&mut self.state)?;
+
+        // Order matters here - `get_new_nonce` acquires connection, so we need to call it before next acquire
+        // Borrow checker note: &mut borrow a few lines above is disjoint from this field
+        let nonce = Self::get_new_nonce(&self.db, *root_key_history_id).await?;
+
+        let mut ciphertext_buffer = plaintext.write();
+        let ciphertext_buffer: &mut Vec<u8> = ciphertext_buffer.as_mut();
+        root_key.encrypt_in_place(&nonce, v1::TAG, &mut *ciphertext_buffer)?;
+
+        let ciphertext = std::mem::take(ciphertext_buffer);
+
+        let mut conn = self.db.get().await?;
+        let aead_id: i32 = insert_into(schema::aead_encrypted::table)
+            .values(&models::NewAeadEncrypted {
+                ciphertext,
+                tag: v1::TAG.to_vec(),
+                current_nonce: nonce.to_vec(),
+                schema_version: 1,
+                associated_root_key_id: *root_key_history_id,
+                created_at: Utc::now().into(),
+            })
+            .returning(schema::aead_encrypted::id)
+            .get_result(&mut conn)
+            .await?;
+
+        Ok(aead_id)
+    }
+
+    #[message]
+    pub fn get_state(&self) -> VaultState {
+        self.state.discriminant()
+    }
+
+    #[message]
+    pub fn sign_integrity(
+        &mut self,
+        mac_input: Vec<u8>,
+    ) -> Result<(RootKeyHistoryId, Vec<u8>), Error> {
+        let Unsealed {
+            root_key,
+            root_key_history_id,
+        } = Self::expect_unsealed(&mut self.state)?;
+
+        let mut hmac = root_key.0.read_inline(|k| {
+            HmacSha256::new_from_slice(k)
+                .unwrap_or_else(|_| unreachable!("HMAC accepts keys of any size"))
+        });
+        hmac.update(&root_key_history_id.to_raw().to_be_bytes());
+        hmac.update(&mac_input);
+
+        let mac = hmac.finalize().into_bytes().to_vec();
+        Ok((*root_key_history_id, mac))
+    }
+
+    #[message]
+    pub fn verify_integrity(
+        &mut self,
+        mac_input: Vec<u8>,
+        expected_mac: Vec<u8>,
+        key_version: RootKeyHistoryId,
+    ) -> Result<bool, Error> {
+        let Unsealed {
+            root_key,
+            root_key_history_id,
+        } = Self::expect_unsealed(&mut self.state)?;
+
+        if *root_key_history_id != key_version {
+            return Ok(false);
+        }
+
+        let mut hmac = root_key.0.read_inline(|k| {
+            HmacSha256::new_from_slice(k)
+                .unwrap_or_else(|_| unreachable!("HMAC accepts keys of any size"))
+        });
+        hmac.update(&key_version.to_raw().to_be_bytes());
+        hmac.update(&mac_input);
+
+        Ok(hmac.verify_slice(&expected_mac).is_ok())
+    }
+}
+
+impl Message<ProposalApproved> for Vault {
+    type Reply = ();
+
+    /// Every subscriber sees every approval and acts only on the kinds it owns.
+    async fn handle(
+        &mut self,
+        msg: ProposalApproved,
+        _ctx: &mut kameo::prelude::Context<Self, Self::Reply>,
+    ) -> Self::Reply {
+        let ProposalKind::ApproveSdkClient(settings) = msg.kind else {
+            return;
+        };
+
+        if let Err(error) = self.approve_sdk_client(settings.client_id).await {
+            error!(
+                ?error,
+                proposal_id = msg.id.to_raw(),
+                "Failed to execute an approved proposal"
+            );
+        }
+    }
+}
+
+impl Vault {
+    /// Attests an approved SDK client with the root key.
+    ///
+    /// Builds the envelope from its parts rather than calling `integrity::sign_entity`,
+    /// which would have this actor ask itself for a signature and deadlock.
+    async fn approve_sdk_client(&mut self, client_id: i32) -> Result<(), Error> {
+        use crate::peers::client::ClientCredentials;
+        use arbiter_crypto::authn;
+
+        // Cloned so the connection does not hold a borrow of `self` across `sign_integrity`.
+        let db = self.db.clone();
+        let mut conn = db.get().await?;
+
+        let pubkey_bytes: Vec<u8> = schema::program_client::table
+            .find(client_id)
+            .select(schema::program_client::public_key)
+            .first(&mut conn)
+            .await?;
+
+        let pubkey =
+            authn::PublicKey::try_from(pubkey_bytes.as_slice()).map_err(|()| Error::InvalidKey)?;
+        let credentials = ClientCredentials { pubkey };
+
+        let (entity_id, mac_input) = integrity::envelope_input(&credentials, client_id);
+        let (key_version, mac) = self.sign_integrity(mac_input)?;
+
+        integrity::store_envelope::<ClientCredentials>(&mut conn, entity_id, key_version, mac)
+            .await?;
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::actors::GlobalActors;
+
+    use super::*;
+
+    async fn bootstrapped_actor(db: &db::DatabasePool) -> Vault {
+        let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+            .await
+            .unwrap();
+        actor.bootstrap(KeyCell::from([0u8; 32])).await.unwrap();
+        actor
+    }
+
+    #[tokio::test]
+    #[test_log::test]
+    async fn nonce_monotonic_even_when_nonce_allocation_interleaves() {
+        let db = db::create_test_pool().await;
+        let mut actor = bootstrapped_actor(&db).await;
+        let State::Unsealed(Unsealed {
+            root_key_history_id,
+            ..
+        }) = actor.state
+        else {
+            panic!("expected unsealed state");
+        };
+
+        let n1 = Vault::get_new_nonce(&db, root_key_history_id)
+            .await
+            .unwrap();
+        let n2 = Vault::get_new_nonce(&db, root_key_history_id)
+            .await
+            .unwrap();
+        assert!(n2.to_vec() > n1.to_vec(), "nonce must increase");
+
+        let mut conn = db.get().await.unwrap();
+        let root_row: RootKeyHistory = schema::root_key_history::table
+            .select(RootKeyHistory::as_select())
+            .first(&mut conn)
+            .await
+            .unwrap();
+        assert_eq!(root_row.data_encryption_nonce, n2.to_vec());
+
+        let id = actor
+            .create_new(SafeCell::new(b"post-interleave".to_vec()))
+            .await
+            .unwrap();
+        let row: models::AeadEncrypted = schema::aead_encrypted::table
+            .filter(schema::aead_encrypted::id.eq(id))
+            .select(models::AeadEncrypted::as_select())
+            .first(&mut conn)
+            .await
+            .unwrap();
+        assert!(
+            row.current_nonce > n2.to_vec(),
+            "next write must advance nonce"
+        );
+    }
+
+    #[tokio::test]
+    #[test_log::test]
+    async fn rekey_does_not_restart_the_data_nonce_counter() {
+        let db = db::create_test_pool().await;
+        let mut actor = bootstrapped_actor(&db).await;
+
+        let before = actor
+            .create_new(SafeCell::new(b"before-rekey".to_vec()))
+            .await
+            .unwrap();
+
+        actor.rekey_root_key(KeyCell::from([7u8; 32])).await.unwrap();
+
+        let after = actor
+            .create_new(SafeCell::new(b"after-rekey".to_vec()))
+            .await
+            .unwrap();
+
+        let mut conn = db.get().await.unwrap();
+
+        // One root key, one row: the root key never changed, so its history did not fork.
+        let rows: i64 = schema::root_key_history::table
+            .count()
+            .get_result(&mut conn)
+            .await
+            .unwrap();
+        assert_eq!(rows, 1, "a seal-key re-key must not append a root key row");
+
+        // Fetch each nonce by its own id, rather than `eq_any` (whose row order is
+        // unspecified), and assert the counter strictly advanced. A weaker `assert_ne!` would
+        // still pass if the counter reset, as long as the two nonces happened to differ.
+        let before_nonce: Vec<u8> = schema::aead_encrypted::table
+            .find(before)
+            .select(schema::aead_encrypted::current_nonce)
+            .first(&mut conn)
+            .await
+            .unwrap();
+        let after_nonce: Vec<u8> = schema::aead_encrypted::table
+            .find(after)
+            .select(schema::aead_encrypted::current_nonce)
+            .first(&mut conn)
+            .await
+            .unwrap();
+        assert!(
+            after_nonce > before_nonce,
+            "nonce counter must keep advancing across a rekey, not reset"
+        );
+    }
+
+    #[tokio::test]
+    #[test_log::test]
+    async fn rekey_invalidates_the_old_seal_key() {
+        let db = db::create_test_pool().await;
+        let mut actor = bootstrapped_actor(&db).await;
+
+        actor.rekey_root_key(KeyCell::from([7u8; 32])).await.unwrap();
+        actor.seal().await.unwrap();
+
+        // A no-op rekey would leave the old seal key working; it must not.
+        let err = actor
+            .try_unseal(KeyCell::from([0u8; 32]))
+            .await
+            .unwrap_err();
+        assert!(
+            matches!(err, Error::InvalidKey),
+            "old seal key must no longer unseal after a rekey, got {err:?}"
+        );
+
+        // A failed unseal must leave the sealed state intact: the new seal key must still be
+        // able to unseal on the next attempt.
+        actor.try_unseal(KeyCell::from([7u8; 32])).await.unwrap();
+    }
+
+    #[tokio::test]
+    #[test_log::test]
+    async fn integrity_envelopes_survive_a_rekey() {
+        let db = db::create_test_pool().await;
+        let mut actor = bootstrapped_actor(&db).await;
+
+        let mac_input = b"operator_credentials/1".to_vec();
+        let (key_version, mac) = actor.sign_integrity(mac_input.clone()).unwrap();
+
+        actor.rekey_root_key(KeyCell::from([9u8; 32])).await.unwrap();
+
+        assert!(
+            actor
+                .verify_integrity(mac_input, mac, key_version)
+                .unwrap(),
+            "a seal-key re-key must not invalidate existing attestations"
+        );
+    }
+}

server/crates/arbiter-server/src/actors/vault_coordinator/mod.rs

@@ -0,0 +1,923 @@
+use std::collections::HashMap;
+
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use diesel::{ExpressionMethods as _, QueryDsl};
+use diesel_async::RunQueryDsl;
+use kameo::{Actor, actor::ActorRef, messages, prelude::Message};
+use rand_core::{OsRng, RngCore as _};
+use tracing::error;
+
+use crate::{
+    actors::{
+        proposal_manager::events::ProposalApproved,
+        vault::{Bootstrap, RekeyRootKey, TryUnseal, Vault},
+    },
+    crypto::{KeyCell, derive_key, encryption::v1::Nonce, shamir, shamir::shamir_threshold},
+    db::{
+        self, models,
+        proposal::{ProposalKind, replace_operator},
+        schema,
+    },
+};
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("Already coordinating a bootstrap")]
+    AlreadyBootstrapping,
+    #[error("Already coordinating an unseal")]
+    AlreadyUnsealing,
+    #[error("Rekey not in progress")]
+    NotRekeying,
+    #[error("Bootstrap not in progress")]
+    NotBootstrapping,
+    #[error("Unseal not in progress")]
+    NotUnsealing,
+    #[error("Operator already contributed")]
+    DuplicateContribution,
+    #[error("Operator not found in database")]
+    OperatorNotFound,
+    #[error("Invalid passphrase (decryption failed)")]
+    InvalidPassphrase,
+    #[error("Shamir error: {0}")]
+    Shamir(String),
+    #[error("Database connection error: {0}")]
+    DatabaseConnection(#[from] db::PoolError),
+    #[error("Database query error: {0}")]
+    DatabaseQuery(#[from] diesel::result::Error),
+    #[error("Encryption error")]
+    Encryption,
+    #[error("Vault error")]
+    VaultError,
+    #[error("Two-operator vaults require at least one recovery share")]
+    TwoOperatorsRequireRecovery,
+    #[error("Broken database")]
+    BrokenDatabase,
+    #[error("A committee must have at least one ordinary operator")]
+    EmptyCommittee,
+    #[error("Recovery operators are sleeping")]
+    RecoveryNotActive,
+}
+
+// Passphrases stored as plain Vec<u8> (not SafeCell) so CoordinatorState is Sync.
+// They are ephemeral and dropped immediately after use.
+enum CoordinatorState {
+    Idle,
+    Bootstrapping {
+        declared_count: usize,
+        recovery_count: usize,
+        passphrases: HashMap<i32, Vec<u8>>,
+        recovery_passphrases: HashMap<i32, Vec<u8>>,
+    },
+    Unsealing {
+        threshold: usize,
+        ordinary_passphrases: HashMap<i32, Vec<u8>>,
+        recovery_passphrases: HashMap<i32, Vec<u8>>,
+    },
+    /// Shamir re-key after `replace_operator` or `trigger_rekey` is approved (§3.3).
+    /// Collects new passphrases from all current operators, then generates a fresh seal key,
+    /// re-splits it, and re-encrypts the vault root key.
+    Rekeying {
+        ordinary_count: usize,
+        recovery_count: usize,
+        passphrases: HashMap<i32, Vec<u8>>,
+        recovery_passphrases: HashMap<i32, Vec<u8>>,
+    },
+}
+
+#[derive(Actor)]
+pub struct VaultCoordinator {
+    db: db::DatabasePool,
+    vault: ActorRef<Vault>,
+    state: CoordinatorState,
+}
+
+impl VaultCoordinator {
+    pub const fn new(db: db::DatabasePool, vault: ActorRef<Vault>) -> Self {
+        Self {
+            db,
+            vault,
+            state: CoordinatorState::Idle,
+        }
+    }
+}
+
+const SHARE_AAD: &[u8] = b"arbiter/shamir-share/v1";
+
+fn encrypt_share(
+    passphrase_bytes: Vec<u8>,
+    share: &[u8],
+) -> Result<(Vec<u8>, Vec<u8>, Vec<u8>), Error> {
+    let mut share_salt = vec![0u8; 32];
+    OsRng.fill_bytes(&mut share_salt);
+
+    let mut passphrase_cell = SafeCell::new(passphrase_bytes);
+    let mut share_seal_key = derive_key(&mut passphrase_cell, &share_salt);
+
+    let nonce = Nonce::default();
+    let encrypted_share = share_seal_key
+        .encrypt(&nonce, SHARE_AAD, share)
+        .map_err(|_| Error::Encryption)?;
+
+    Ok((encrypted_share, nonce.to_vec(), share_salt))
+}
+
+fn decrypt_share(
+    passphrase_bytes: Vec<u8>,
+    encrypted_share: Vec<u8>,
+    share_nonce_bytes: &[u8],
+    share_salt: &[u8],
+    operator_id: i32,
+) -> Result<Vec<u8>, Error> {
+    let nonce = Nonce::try_from(share_nonce_bytes).map_err(|()| {
+        error!(operator_id, "Invalid nonce in DB");
+        Error::BrokenDatabase
+    })?;
+
+    let mut passphrase_cell = SafeCell::new(passphrase_bytes);
+    let mut share_seal_key = derive_key(&mut passphrase_cell, share_salt);
+
+    let mut share_buffer = SafeCell::new(encrypted_share);
+    share_seal_key
+        .decrypt_in_place(&nonce, SHARE_AAD, &mut share_buffer)
+        .map_err(|_| Error::InvalidPassphrase)?;
+
+    Ok(share_buffer.read().clone())
+}
+
+/// Records the threshold of the split that produced the stored shares.
+async fn store_threshold(conn: &mut db::DatabaseConnection, threshold: usize) -> Result<(), Error> {
+    // A threshold that doesn't fit in the column is a bug, not a real empty-committee refusal.
+    let threshold = i32::try_from(threshold).map_err(|_| Error::BrokenDatabase)?;
+    let rows_updated = diesel::update(schema::arbiter_settings::table)
+        .set(schema::arbiter_settings::shamir_threshold.eq(Some(threshold)))
+        .execute(conn)
+        .await?;
+    // The singleton row always exists (up.sql seeds it), so anything else means the update did
+    // not land -- bootstrap would then report success while the threshold stays NULL forever.
+    if rows_updated != 1 {
+        return Err(Error::BrokenDatabase);
+    }
+    Ok(())
+}
+
+/// Reads back the threshold recorded at bootstrap or re-key time.
+async fn load_threshold(conn: &mut db::DatabaseConnection) -> Result<usize, Error> {
+    let stored: Option<i32> = schema::arbiter_settings::table
+        .select(schema::arbiter_settings::shamir_threshold)
+        .first(conn)
+        .await?;
+
+    // A missing or out-of-range value here means the recorded threshold is corrupt, not that the
+    // committee is genuinely empty -- `EmptyCommittee` is reserved for the real domain refusal.
+    stored
+        .and_then(|threshold| usize::try_from(threshold).ok())
+        .ok_or(Error::BrokenDatabase)
+}
+
+/// §3.4: Split the seal key across ordinary + recovery operators.
+/// Threshold = `shamir_threshold(ordinary_count)`; total shares = ordinary + recovery.
+/// When `ordinary_count` == 1 (threshold = 1), vsss-rs does not support a proper split,
+/// so each share is the seal key itself — any single participant can reconstruct.
+async fn finalize_bootstrap(
+    db: db::DatabasePool,
+    vault: ActorRef<Vault>,
+    ordinary_passphrases: HashMap<i32, Vec<u8>>,
+    recovery_passphrases: HashMap<i32, Vec<u8>>,
+) -> Result<(), Error> {
+    let ordinary_count = ordinary_passphrases.len();
+    let recovery_count = recovery_passphrases.len();
+    let total = ordinary_count + recovery_count;
+    let threshold = shamir_threshold(ordinary_count).ok_or(Error::EmptyCommittee)?;
+
+    let mut seal_key_bytes = [0u8; 32];
+    OsRng.fill_bytes(&mut seal_key_bytes);
+
+    // threshold == 1 means any single share reconstructs the key (degenerate split).
+    // vsss-rs requires threshold >= 2, so we store the key directly in this case.
+    let shares: Vec<Vec<u8>> = if threshold >= 2 {
+        shamir::split_key(threshold, total, &seal_key_bytes, OsRng)
+            .map_err(|e| Error::Shamir(e.to_string()))?
+    } else {
+        std::iter::repeat_with(|| seal_key_bytes.to_vec()).take(total).collect()
+    };
+
+    let seal_key = KeyCell::from(seal_key_bytes);
+
+    let mut conn = db.get().await?;
+    let mut shares_iter = shares.into_iter();
+
+    for (operator_id_raw, passphrase_bytes) in ordinary_passphrases {
+        let share = shares_iter
+            .next()
+            .expect("split_key returned enough shares");
+        let (encrypted_share, nonce_bytes, share_salt) = encrypt_share(passphrase_bytes, &share)?;
+
+        diesel::replace_into(schema::operator::table)
+            .values((
+                schema::operator::id.eq(Some(operator_id_raw)),
+                schema::operator::share.eq(&encrypted_share),
+                schema::operator::share_nonce.eq(&nonce_bytes),
+                schema::operator::share_salt.eq(&share_salt),
+                schema::operator::created_at.eq(models::SqliteTimestamp::now()),
+                schema::operator::updated_at.eq(models::SqliteTimestamp::now()),
+            ))
+            .execute(&mut conn)
+            .await?;
+    }
+
+    for (recovery_id_raw, passphrase_bytes) in recovery_passphrases {
+        let share = shares_iter
+            .next()
+            .expect("split_key returned enough shares");
+        let (encrypted_share, nonce_bytes, share_salt) = encrypt_share(passphrase_bytes, &share)?;
+
+        diesel::replace_into(schema::recovery_operator::table)
+            .values((
+                schema::recovery_operator::id.eq(recovery_id_raw),
+                schema::recovery_operator::share.eq(&encrypted_share),
+                schema::recovery_operator::share_nonce.eq(&nonce_bytes),
+                schema::recovery_operator::share_salt.eq(&share_salt),
+                schema::recovery_operator::created_at.eq(models::SqliteTimestamp::now()),
+                schema::recovery_operator::updated_at.eq(models::SqliteTimestamp::now()),
+            ))
+            .execute(&mut conn)
+            .await?;
+    }
+
+    store_threshold(&mut conn, threshold).await?;
+
+    vault.ask(Bootstrap { seal_key }).await.map_err(|err| {
+        error!(?err, "Vault bootstrap failed");
+        Error::VaultError
+    })?;
+
+    Ok(())
+}
+
+/// §3.5: Unseal using any threshold-sized mix of ordinary + recovery shares.
+async fn finalize_unseal(
+    db: db::DatabasePool,
+    vault: ActorRef<Vault>,
+    ordinary_passphrases: HashMap<i32, Vec<u8>>,
+    recovery_passphrases: HashMap<i32, Vec<u8>>,
+) -> Result<(), Error> {
+    let mut conn = db.get().await?;
+
+    // Determine whether shares were stored as raw keys (threshold=1) or vsss-rs splits (threshold>=2).
+    let threshold = load_threshold(&mut conn).await?;
+
+    let mut shares: Vec<Vec<u8>> = Vec::new();
+
+    for (operator_id_raw, passphrase_bytes) in ordinary_passphrases {
+        let (encrypted_share, share_nonce_bytes, share_salt): (Vec<u8>, Vec<u8>, Vec<u8>) =
+            schema::operator::table
+                .filter(schema::operator::id.eq(Some(operator_id_raw)))
+                .select((
+                    schema::operator::share,
+                    schema::operator::share_nonce,
+                    schema::operator::share_salt,
+                ))
+                .first(&mut conn)
+                .await
+                .map_err(|_| Error::OperatorNotFound)?;
+
+        shares.push(decrypt_share(
+            passphrase_bytes,
+            encrypted_share,
+            &share_nonce_bytes,
+            &share_salt,
+            operator_id_raw,
+        )?);
+    }
+
+    for (recovery_id_raw, passphrase_bytes) in recovery_passphrases {
+        let (encrypted_share, share_nonce_bytes, share_salt): (Vec<u8>, Vec<u8>, Vec<u8>) =
+            schema::recovery_operator::table
+                .find(recovery_id_raw)
+                .select((
+                    schema::recovery_operator::share,
+                    schema::recovery_operator::share_nonce,
+                    schema::recovery_operator::share_salt,
+                ))
+                .first(&mut conn)
+                .await
+                .map_err(|_| Error::OperatorNotFound)?;
+
+        shares.push(decrypt_share(
+            passphrase_bytes,
+            encrypted_share,
+            &share_nonce_bytes,
+            &share_salt,
+            recovery_id_raw,
+        )?);
+    }
+
+    // When threshold==1, shares are raw 32-byte seal keys (vsss-rs cannot split 1-of-N).
+    // Any single decrypted share is the key itself.
+    let seal_key_bytes: [u8; 32] = if threshold <= 1 {
+        let raw = shares
+            .into_iter()
+            .next()
+            .ok_or_else(|| Error::Shamir("No shares available".into()))?;
+        raw.try_into()
+            .map_err(|_| Error::Shamir("Invalid share length".into()))?
+    } else {
+        shamir::combine_shares(&shares).map_err(|e| Error::Shamir(e.to_string()))?
+    };
+
+    let seal_key = KeyCell::from(seal_key_bytes);
+
+    vault.ask(TryUnseal { seal_key }).await.map_err(|err| {
+        error!(?err, "Vault unseal failed");
+        Error::VaultError
+    })?;
+
+    Ok(())
+}
+
+/// §3.3: Generate a fresh seal key, split across current operators, re-encrypt the vault root key.
+/// Called after `replace_operator` or `trigger_rekey` is approved and all contributors submit.
+async fn finalize_rekey(
+    db: db::DatabasePool,
+    vault: ActorRef<Vault>,
+    ordinary_passphrases: HashMap<i32, Vec<u8>>,
+    recovery_passphrases: HashMap<i32, Vec<u8>>,
+) -> Result<(), Error> {
+    let ordinary_count = ordinary_passphrases.len();
+    let recovery_count = recovery_passphrases.len();
+    let total = ordinary_count + recovery_count;
+    let threshold = shamir_threshold(ordinary_count).ok_or(Error::EmptyCommittee)?;
+
+    let mut new_seal_key_bytes = [0u8; 32];
+    OsRng.fill_bytes(&mut new_seal_key_bytes);
+
+    let shares: Vec<Vec<u8>> = if threshold >= 2 {
+        shamir::split_key(threshold, total, &new_seal_key_bytes, OsRng)
+            .map_err(|e| Error::Shamir(e.to_string()))?
+    } else {
+        std::iter::repeat_with(|| new_seal_key_bytes.to_vec())
+            .take(total)
+            .collect()
+    };
+
+    let mut conn = db.get().await?;
+    let mut shares_iter = shares.into_iter();
+
+    for (operator_id_raw, passphrase_bytes) in ordinary_passphrases {
+        let share = shares_iter
+            .next()
+            .expect("split_key returned enough shares");
+        let (encrypted_share, nonce_bytes, share_salt) = encrypt_share(passphrase_bytes, &share)?;
+
+        diesel::replace_into(schema::operator::table)
+            .values((
+                schema::operator::id.eq(Some(operator_id_raw)),
+                schema::operator::share.eq(&encrypted_share),
+                schema::operator::share_nonce.eq(&nonce_bytes),
+                schema::operator::share_salt.eq(&share_salt),
+                schema::operator::created_at.eq(models::SqliteTimestamp::now()),
+                schema::operator::updated_at.eq(models::SqliteTimestamp::now()),
+            ))
+            .execute(&mut conn)
+            .await?;
+    }
+
+    for (recovery_id_raw, passphrase_bytes) in recovery_passphrases {
+        let share = shares_iter
+            .next()
+            .expect("split_key returned enough shares");
+        let (encrypted_share, nonce_bytes, share_salt) = encrypt_share(passphrase_bytes, &share)?;
+
+        diesel::replace_into(schema::recovery_operator::table)
+            .values((
+                schema::recovery_operator::id.eq(recovery_id_raw),
+                schema::recovery_operator::share.eq(&encrypted_share),
+                schema::recovery_operator::share_nonce.eq(&nonce_bytes),
+                schema::recovery_operator::share_salt.eq(&share_salt),
+                schema::recovery_operator::created_at.eq(models::SqliteTimestamp::now()),
+                schema::recovery_operator::updated_at.eq(models::SqliteTimestamp::now()),
+            ))
+            .execute(&mut conn)
+            .await?;
+    }
+
+    store_threshold(&mut conn, threshold).await?;
+
+    drop(conn);
+
+    let new_seal_key = KeyCell::from(new_seal_key_bytes);
+    vault
+        .ask(RekeyRootKey { new_seal_key })
+        .await
+        .map_err(|err| {
+            error!(?err, "Vault rekey failed");
+            Error::VaultError
+        })?;
+
+    Ok(())
+}
+
+#[messages]
+impl VaultCoordinator {
+    /// Phase 1 of multi-operator bootstrap: declare the committee size.
+    #[message]
+    #[expect(clippy::unused_async, reason = "kameo requires messages to be async")]
+    pub async fn start_bootstrap(
+        &mut self,
+        operator_id: i32,
+        declared_count: usize,
+        recovery_count: usize,
+    ) -> Result<(), Error> {
+        let _ = operator_id; // fixme!: any authenticated operator may announce the committee size. the first call wins
+        if !matches!(self.state, CoordinatorState::Idle) {
+            return Err(Error::AlreadyBootstrapping);
+        }
+        if declared_count == 0 {
+            return Err(Error::EmptyCommittee);
+        }
+        if declared_count == 2 && recovery_count == 0 {
+            return Err(Error::TwoOperatorsRequireRecovery);
+        }
+        self.state = CoordinatorState::Bootstrapping {
+            declared_count,
+            recovery_count,
+            passphrases: HashMap::new(),
+            recovery_passphrases: HashMap::new(),
+        };
+        Ok(())
+    }
+
+    /// Phase 2 of multi-operator bootstrap: ordinary operator contributes a passphrase.
+    /// Returns Ok(true) when all ordinary + recovery operators contributed and bootstrap finalized.
+    #[message]
+    pub async fn contribute_bootstrap(
+        &mut self,
+        operator_id: i32,
+        mut passphrase: SafeCell<Vec<u8>>,
+    ) -> Result<bool, Error> {
+        let CoordinatorState::Bootstrapping {
+            declared_count,
+            recovery_count,
+            passphrases,
+            recovery_passphrases,
+        } = &mut self.state
+        else {
+            return Err(Error::NotBootstrapping);
+        };
+
+        if passphrases.contains_key(&operator_id) {
+            return Err(Error::DuplicateContribution);
+        }
+
+        let passphrase_bytes = passphrase.read().to_vec();
+        passphrases.insert(operator_id, passphrase_bytes);
+
+        if passphrases.len() < *declared_count || recovery_passphrases.len() < *recovery_count {
+            return Ok(false);
+        }
+
+        let CoordinatorState::Bootstrapping {
+            passphrases,
+            recovery_passphrases,
+            ..
+        } = std::mem::replace(&mut self.state, CoordinatorState::Idle)
+        else {
+            unreachable!()
+        };
+
+        finalize_bootstrap(
+            self.db.clone(),
+            self.vault.clone(),
+            passphrases,
+            recovery_passphrases,
+        )
+        .await?;
+        Ok(true)
+    }
+
+    /// Phase 2 of multi-operator bootstrap: recovery operator contributes a passphrase.
+    /// Returns Ok(true) when all contributors are in and bootstrap finalized.
+    #[message]
+    pub async fn contribute_recovery_bootstrap(
+        &mut self,
+        recovery_operator_id: i32,
+        mut passphrase: SafeCell<Vec<u8>>,
+    ) -> Result<bool, Error> {
+        let CoordinatorState::Bootstrapping {
+            declared_count,
+            recovery_count,
+            passphrases,
+            recovery_passphrases,
+        } = &mut self.state
+        else {
+            return Err(Error::NotBootstrapping);
+        };
+
+        if recovery_passphrases.contains_key(&recovery_operator_id) {
+            return Err(Error::DuplicateContribution);
+        }
+
+        let passphrase_bytes = passphrase.read().to_vec();
+        recovery_passphrases.insert(recovery_operator_id, passphrase_bytes);
+
+        if passphrases.len() < *declared_count || recovery_passphrases.len() < *recovery_count {
+            return Ok(false);
+        }
+
+        let CoordinatorState::Bootstrapping {
+            passphrases,
+            recovery_passphrases,
+            ..
+        } = std::mem::replace(&mut self.state, CoordinatorState::Idle)
+        else {
+            unreachable!()
+        };
+
+        finalize_bootstrap(
+            self.db.clone(),
+            self.vault.clone(),
+            passphrases,
+            recovery_passphrases,
+        )
+        .await?;
+        Ok(true)
+    }
+
+    /// Contribute a passphrase for vault unseal (ordinary operator).
+    /// Returns Ok(true) when threshold reached and vault is unsealed.
+    #[message]
+    pub async fn contribute_unseal(
+        &mut self,
+        operator_id: i32,
+        mut passphrase: SafeCell<Vec<u8>>,
+    ) -> Result<bool, Error> {
+        self.ensure_unsealing_state().await?;
+
+        let CoordinatorState::Unsealing {
+            threshold,
+            ordinary_passphrases,
+            recovery_passphrases,
+        } = &mut self.state
+        else {
+            return Err(Error::NotUnsealing);
+        };
+
+        if ordinary_passphrases.contains_key(&operator_id) {
+            return Err(Error::DuplicateContribution);
+        }
+
+        let passphrase_bytes = passphrase.read().to_vec();
+        ordinary_passphrases.insert(operator_id, passphrase_bytes);
+
+        if ordinary_passphrases.len() + recovery_passphrases.len() < *threshold {
+            return Ok(false);
+        }
+
+        self.do_finalize_unseal().await
+    }
+
+    /// Contribute a passphrase for vault unseal (recovery operator, §3.5).
+    /// Recovery operators may contribute during unseal when recovery is active.
+    /// Returns Ok(true) when threshold reached and vault is unsealed.
+    #[message]
+    pub async fn contribute_recovery_unseal(
+        &mut self,
+        recovery_operator_id: i32,
+        mut passphrase: SafeCell<Vec<u8>>,
+    ) -> Result<bool, Error> {
+        {
+            let mut conn = self.db.get().await?;
+            if !db::recovery::is_active(&mut conn).await? {
+                return Err(Error::RecoveryNotActive);
+            }
+        }
+
+        self.ensure_unsealing_state().await?;
+
+        let CoordinatorState::Unsealing {
+            threshold,
+            ordinary_passphrases,
+            recovery_passphrases,
+        } = &mut self.state
+        else {
+            return Err(Error::NotUnsealing);
+        };
+
+        if recovery_passphrases.contains_key(&recovery_operator_id) {
+            return Err(Error::DuplicateContribution);
+        }
+
+        let passphrase_bytes = passphrase.read().to_vec();
+        recovery_passphrases.insert(recovery_operator_id, passphrase_bytes);
+
+        if ordinary_passphrases.len() + recovery_passphrases.len() < *threshold {
+            return Ok(false);
+        }
+
+        self.do_finalize_unseal().await
+    }
+}
+
+impl VaultCoordinator {
+    /// Initializes `CoordinatorState::Unsealing` on first call if still `Idle`.
+    /// Threshold comes from the recorded split parameters (§3.4), not from a live row count.
+    async fn ensure_unsealing_state(&mut self) -> Result<(), Error> {
+        if matches!(self.state, CoordinatorState::Idle) {
+            let mut conn = self.db.get().await?;
+            let threshold = load_threshold(&mut conn).await?;
+            drop(conn);
+            self.state = CoordinatorState::Unsealing {
+                threshold,
+                ordinary_passphrases: HashMap::new(),
+                recovery_passphrases: HashMap::new(),
+            };
+        }
+        Ok(())
+    }
+
+    /// Moves state back to Idle and calls finalize_unseal.
+    async fn do_finalize_unseal(&mut self) -> Result<bool, Error> {
+        let CoordinatorState::Unsealing {
+            ordinary_passphrases,
+            recovery_passphrases,
+            ..
+        } = std::mem::replace(&mut self.state, CoordinatorState::Idle)
+        else {
+            unreachable!()
+        };
+
+        finalize_unseal(
+            self.db.clone(),
+            self.vault.clone(),
+            ordinary_passphrases,
+            recovery_passphrases,
+        )
+        .await?;
+        Ok(true)
+    }
+
+    async fn do_finalize_rekey(&mut self) -> Result<bool, Error> {
+        let CoordinatorState::Rekeying {
+            passphrases,
+            recovery_passphrases,
+            ..
+        } = std::mem::replace(&mut self.state, CoordinatorState::Idle)
+        else {
+            unreachable!()
+        };
+
+        finalize_rekey(
+            self.db.clone(),
+            self.vault.clone(),
+            passphrases,
+            recovery_passphrases,
+        )
+        .await?;
+        Ok(true)
+    }
+}
+
+#[messages]
+impl VaultCoordinator {
+    /// Begin Shamir re-key after a key-rotation proposal is approved (§3.3).
+    /// Queries the current operator and recovery operator counts from the DB,
+    /// then transitions to Rekeying state awaiting contributions from all of them.
+    #[message]
+    pub async fn start_rekey(&mut self) -> Result<(), Error> {
+        self.ensure_idle()?;
+        let mut conn = self.db.get().await?;
+        let ordinary_count: i64 = schema::operator_identity::table
+            .count()
+            .get_result(&mut conn)
+            .await?;
+        let recovery_count: i64 = schema::recovery_operator_identity::table
+            .count()
+            .get_result(&mut conn)
+            .await?;
+        self.state = CoordinatorState::Rekeying {
+            ordinary_count: ordinary_count as usize,
+            recovery_count: recovery_count as usize,
+            passphrases: HashMap::new(),
+            recovery_passphrases: HashMap::new(),
+        };
+        Ok(())
+    }
+
+    /// Contribute an ordinary operator passphrase for the re-key.
+    /// Returns Ok(true) when all contributors have submitted and the re-key is complete.
+    #[message]
+    pub async fn contribute_rekey(
+        &mut self,
+        operator_id: i32,
+        mut passphrase: SafeCell<Vec<u8>>,
+    ) -> Result<bool, Error> {
+        let CoordinatorState::Rekeying {
+            ordinary_count,
+            recovery_count,
+            passphrases,
+            recovery_passphrases,
+        } = &mut self.state
+        else {
+            return Err(Error::NotRekeying);
+        };
+
+        if passphrases.contains_key(&operator_id) {
+            return Err(Error::DuplicateContribution);
+        }
+
+        passphrases.insert(operator_id, passphrase.read().to_vec());
+
+        if passphrases.len() < *ordinary_count || recovery_passphrases.len() < *recovery_count {
+            return Ok(false);
+        }
+
+        self.do_finalize_rekey().await
+    }
+
+    /// Contribute a recovery operator passphrase for the re-key.
+    /// Returns Ok(true) when all contributors have submitted and the re-key is complete.
+    #[message]
+    pub async fn contribute_recovery_rekey(
+        &mut self,
+        recovery_operator_id: i32,
+        mut passphrase: SafeCell<Vec<u8>>,
+    ) -> Result<bool, Error> {
+        let CoordinatorState::Rekeying {
+            ordinary_count,
+            recovery_count,
+            passphrases,
+            recovery_passphrases,
+        } = &mut self.state
+        else {
+            return Err(Error::NotRekeying);
+        };
+
+        if recovery_passphrases.contains_key(&recovery_operator_id) {
+            return Err(Error::DuplicateContribution);
+        }
+
+        recovery_passphrases.insert(recovery_operator_id, passphrase.read().to_vec());
+
+        if passphrases.len() < *ordinary_count || recovery_passphrases.len() < *recovery_count {
+            return Ok(false);
+        }
+
+        self.do_finalize_rekey().await
+    }
+}
+
+impl Message<ProposalApproved> for VaultCoordinator {
+    type Reply = ();
+
+    /// Every subscriber sees every approval and acts only on the kinds it owns.
+    async fn handle(
+        &mut self,
+        msg: ProposalApproved,
+        _ctx: &mut kameo::prelude::Context<Self, Self::Reply>,
+    ) -> Self::Reply {
+        let result = match msg.kind {
+            ProposalKind::ReplaceOperator(settings) => self.replace_operator(&settings).await,
+            ProposalKind::TriggerRekey => self.start_rekey().await,
+            _ => return,
+        };
+
+        if let Err(error) = result {
+            error!(
+                ?error,
+                proposal_id = msg.id.to_raw(),
+                "Failed to execute an approved proposal"
+            );
+        }
+    }
+}
+
+impl VaultCoordinator {
+    /// The coordinator runs one ceremony at a time; anything that starts a new one has to say
+    /// so before it changes any state the ceremony depends on.
+    const fn ensure_idle(&self) -> Result<(), Error> {
+        if matches!(self.state, CoordinatorState::Idle) {
+            Ok(())
+        } else {
+            Err(Error::AlreadyBootstrapping)
+        }
+    }
+
+    /// Replaces the operator's public key in place, keeping their id and history, drops the
+    /// share that key no longer matches, then begins a coordinated re-key (§3.3).
+    async fn replace_operator(
+        &mut self,
+        settings: &replace_operator::Settings,
+    ) -> Result<(), Error> {
+        // Checked before anything is written. The re-key is what gives the replaced operator
+        // a share they can use; if the coordinator is mid-ceremony, `start_rekey` refuses, and
+        // swapping the key and destroying the share first would leave that operator locked
+        // out with no re-key running and nothing to undo it -- the caller only logs the error.
+        self.ensure_idle()?;
+
+        let mut conn = self.db.get().await?;
+
+        diesel::update(schema::operator_identity::table)
+            .filter(schema::operator_identity::id.eq(settings.old_operator_id))
+            .set(schema::operator_identity::public_key.eq(&settings.new_pubkey))
+            .execute(&mut conn)
+            .await?;
+
+        // Drop the stale Shamir share; finalize_rekey stores a fresh one.
+        diesel::delete(schema::operator::table)
+            .filter(schema::operator::id.eq(Some(settings.old_operator_id)))
+            .execute(&mut conn)
+            .await?;
+
+        drop(conn);
+
+        self.start_rekey().await
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{CoordinatorState, Error, VaultCoordinator};
+    use crate::{
+        actors::{GlobalActors, vault::Vault},
+        db::{self, models::OperatorIdentityId, proposal::replace_operator, schema},
+    };
+
+    use diesel::{ExpressionMethods as _, QueryDsl as _, dsl::insert_into};
+    use diesel_async::RunQueryDsl;
+    use kameo::actor::Spawn as _;
+    use std::collections::HashMap;
+
+    /// An approved `ReplaceOperator` that arrives while another ceremony is running must
+    /// change nothing. Swapping the public key and deleting the share are only safe because a
+    /// re-key follows and hands the operator a share for the new key; when `start_rekey`
+    /// refuses, the operator would otherwise be left holding a key with no share, and the
+    /// caller does nothing with the error but log it.
+    #[tokio::test]
+    async fn a_refused_rekey_leaves_the_operator_untouched() {
+        let pool = db::create_test_pool().await;
+        let mut conn = pool.get().await.unwrap();
+
+        let old_key = rand::random::<[u8; 32]>().to_vec();
+        let operator_id: OperatorIdentityId = insert_into(schema::operator_identity::table)
+            .values(schema::operator_identity::public_key.eq(&old_key))
+            .returning(schema::operator_identity::id)
+            .get_result(&mut conn)
+            .await
+            .unwrap();
+        insert_into(schema::operator::table)
+            .values((
+                schema::operator::id.eq(Some(operator_id)),
+                schema::operator::share.eq(vec![1u8; 32]),
+                schema::operator::share_nonce.eq(vec![2u8; 24]),
+                schema::operator::share_salt.eq(vec![3u8; 32]),
+            ))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+        drop(conn);
+
+        let vault = Vault::spawn(
+            Vault::new(pool.clone(), GlobalActors::spawn_message_bus())
+                .await
+                .unwrap(),
+        );
+        let mut coordinator = VaultCoordinator::new(pool.clone(), vault);
+        coordinator.state = CoordinatorState::Rekeying {
+            ordinary_count: 2,
+            recovery_count: 0,
+            passphrases: HashMap::new(),
+            recovery_passphrases: HashMap::new(),
+        };
+
+        let result = coordinator
+            .replace_operator(&replace_operator::Settings {
+                old_operator_id: operator_id,
+                new_pubkey: vec![9u8; 32],
+            })
+            .await;
+        assert!(
+            matches!(result, Err(Error::AlreadyBootstrapping)),
+            "a busy coordinator must refuse the replacement, got {result:?}"
+        );
+
+        let mut conn = pool.get().await.unwrap();
+        let stored_key: Vec<u8> = schema::operator_identity::table
+            .find(operator_id)
+            .select(schema::operator_identity::public_key)
+            .first(&mut conn)
+            .await
+            .unwrap();
+        assert_eq!(
+            stored_key, old_key,
+            "the public key must not be swapped when no re-key can follow"
+        );
+
+        let shares: i64 = schema::operator::table
+            .filter(schema::operator::id.eq(Some(operator_id)))
+            .count()
+            .get_result(&mut conn)
+            .await
+            .unwrap();
+        assert_eq!(shares, 1, "the operator's share must not be destroyed");
+    }
+}