fix(vault): apply Shamir custody review feedback

Reviewed-on: #102
Reviewed-by: Stas <business@jexter.tech>

.gitignore

@@ -3,4 +3,4 @@ scripts/__pycache__/
 .DS_Store
 .cargo/config.toml
 .vscode/
-docs/
+docs/superpowers

AGENTS.md

@@ -1,13 +1,16 @@
 # AGENTS.md
 
-This file provides guidance to Codex (Codex.ai/code) when working with code in this repository.
+Guidance for coding agents (Claude Code, Codex, …) working in this repository.
 
 ## Project Overview
 
-Arbiter is a **permissioned signing service** for cryptocurrency wallets. It consists of:
+Arbiter is a **permissioned signing service** for cryptocurrency wallets:
+
 - **`server/`** — Rust gRPC daemon that holds encrypted keys and enforces policies
-- **`useragent/`** — Flutter desktop app (macOS/Windows) with a Rust backend via Rinf
+- **`useragent/`** — Flutter app (desktop + mobile + web targets) with a Rust core via `flutter_rust_bridge`
-- **`protobufs/`** — Protocol Buffer definitions shared between server and client
+- **`protobufs/`** — Protocol Buffer definitions shared between server and clients
+- **`docs/`** — `ARCHITECTURE.md` (peer types, flows, threat model) and `IMPLEMENTATION.md`; treat them as the design source of truth and update them when behaviour changes
+- **`scripts/`** — helper scripts, e.g. `gen_erc20_registry.py`
 
 The vault never exposes key material; it only produces signatures when requests satisfy configured policies.
 
@@ -18,7 +21,7 @@ Tools are managed via [mise](https://mise.jdx.dev/). Install all required tools:
 mise install
 ```
 
-Key versions: Rust 1.93.0 (with clippy), Flutter 3.38.9-stable, protoc 29.6, diesel_cli 2.3.6 (sqlite).
+Key versions live in `mise.toml` (currently Rust 1.95.0 with clippy, Flutter 3.41.7-stable, protoc 29.6, diesel_cli 2.3.7 with `sqlite-bundled`, Python 3.14). Also provided there: `cargo-nextest`, `cargo-audit`, `cargo-vet`, `cargo-shear`, `cargo-mutants`, `cargo-features-manager`, `cargo-edit`, `ast-grep`, `flutter_rust_bridge_codegen`.
 
 ## Server (Rust workspace at `server/`)
 
@@ -26,10 +29,14 @@ Key versions: Rust 1.93.0 (with clippy), Flutter 3.38.9-stable, protoc 29.6, die
 
 | Crate | Purpose |
 |---|---|
-| `arbiter-proto` | Generated gRPC stubs + protobuf types; compiled from `protobufs/*.proto` via `tonic-prost-build` |
+| `arbiter-proto` | Generated gRPC stubs + protobuf types (`tonic-prost-build`); also `ArbiterUrl`, `home_path()`, `BOOTSTRAP_PATH` |
-| `arbiter-server` | Main daemon — actors, DB, EVM policy engine, gRPC service implementation |
+| `arbiter-crypto` | Shared crypto primitives: `authn` (ML-DSA), `safecell` (hardened memory), `hashing::Hashable`, re-exported `x-wing` |
-| `arbiter-useragent` | Rust client library for the user agent side of the gRPC protocol |
+| `arbiter-macros` | `#[derive(Hashable)]` — canonical hashing of structs for the DB integrity layer |
-| `arbiter-client` | Rust client library for SDK clients |
+| `arbiter-server` | Main daemon — actors, peers, DB, EVM policy engine, gRPC service implementation |
+| `arbiter-client` | Rust client library for SDK clients (`ArbiterClient`, EVM wallet, key storage) |
+| `arbiter-tokens-registry` | Generated ERC-20 token registry used by token-transfer policies |
+
+Workspace lints (`server/Cargo.toml`) are strict: most of clippy `pedantic`/`nursery` plus a large restriction set. `as` casts, indexing/slicing, `dbg!`, float arithmetic and undocumented `unsafe` are denied or warned — expect to add an `#[expect(..., reason = "...")]` rather than to silence a lint globally.
 
 ### Common Commands
 
@@ -42,54 +49,78 @@ cargo build
 # Run the server daemon
 cargo run -p arbiter-server
 
-# Run all tests (preferred over cargo test)
+# Run all tests (preferred over cargo test; CI uses --all-features)
 cargo nextest run
 
 # Run a single test
 cargo nextest run <test_name>
 
-# Lint
+# Lint (CI runs it with -D warnings)
-cargo clippy
+cargo clippy --all -- -D warnings
 
 # Security audit
 cargo audit
 
+# Supply-chain review (config in server/supply-chain/)
+cargo vet
+
 # Check unused dependencies
 cargo shear
 
-# Run snapshot tests and update snapshots
+# Mutation testing
-cargo insta review
+cargo mutants
 ```
 
+### CI
+
+Woodpecker pipelines in `.woodpecker/` run on `server/**` changes: `server-lint` (clippy), `server-test` (nextest, `--all-features`), `server-audit`, `server-vet`, plus `useragent-analyze` for the Flutter app.
+
 ### Architecture
 
-The server is actor-based using the **kameo** crate. All long-lived state lives in `GlobalActors`:
+The server is actor-based using the **kameo** crate. Long-lived state lives in `GlobalActors` (`src/actors/mod.rs`):
 
-- **`Bootstrapper`** — Manages the one-time bootstrap token written to `~/.arbiter/bootstrap_token` on first run.
+- **`Bootstrapper`** — one-time bootstrap token, written to `~/.arbiter/bootstrap_token` on first run
-- **`KeyHolder`** — 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.
+- **`Vault`** — encrypted root key and the Sealed/Unsealed state machine; on unseal decrypts the root key into a `memsafe`-backed `SafeCell`
-- **`FlowCoordinator`** — Coordinates cross-connection flow between user agents and SDK clients.
+- **`FlowCoordinator`** — cross-connection flow between operators and SDK clients
-- **`EvmActor`** — Handles EVM transaction policy enforcement and signing.
+- **`OperatorRegistry`** — tracks currently connected operators
+- **`EvmActor`** — EVM transaction policy enforcement and signing
+- **`events`** — a `kameo_actors::MessageBus` (`DeliveryStrategy::Guaranteed`) for cross-actor notifications
 
-Per-connection actors live under `actors/user_agent/` and `actors/client/`, each with `auth` (challenge-response authentication) and `session` (post-auth operations) sub-modules.
+Per-connection state lives under **`src/peers/`**, not `actors/`: `peers/client/` and `peers/operator/`, each with `auth` (challenge-response) and `session` (post-auth) sub-modules; the operator side additionally has `vault_gate/` for the unseal handshake.
 
-**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()`.
+The gRPC surface lives in **`src/grpc/`**, split per peer (`client/`, `operator/`, `common/`) and per direction (`inbound.rs` — requests to the daemon, `outbound.rs` — server-initiated streams), with `request_tracker.rs` correlating the two.
+
+EVM logic is in `src/evm/`: `policies/ether_transfer/`, `policies/token_transfers/`, `abi.rs`, `safe_signer.rs`.
+
+**Database:** SQLite via `diesel-async` + `bb8`. Schema in `src/db/schema.rs`, models in `src/db/models.rs`, embedded migrations in `crates/arbiter-server/migrations/`. DB file lives at `~/.arbiter/arbiter.sqlite`; tests use a temp-file DB via `db::create_test_pool()`.
+
+Entity ids are newtypes generated by the `declare_id!` macro in `db::models` (`OperatorId`, `ChainId`, …), each a `#[repr(transparent)]` wrapper over `i32` with `to_raw`/`from_raw`. Pass these around instead of bare `i32`.
+
+**Row integrity:** sensitive rows are covered by an HMAC-SHA256 envelope (`src/crypto/integrity/`, table `integrity_envelope`), keyed from the vault root key. A struct becomes coverable by deriving `arbiter_macros::Hashable` and implementing `Integrable` (`KIND` + `VERSION`). When adding or changing a covered entity, keep the derive and the payload version in sync — a mismatch surfaces as `PayloadVersionMismatch` or `MacMismatch` at runtime.
 
 **Cryptography:**
-- Authentication: ed25519 (challenge-response, nonce-tracked per peer)
+- Authentication: **ML-DSA-87** (post-quantum, `arbiter-crypto::authn::v1`), challenge-response with per-peer nonce tracking
-- Encryption at rest: XChaCha20-Poly1305 (versioned via `scheme` field for transparent migration on unseal)
+- Encryption at rest: XChaCha20-Poly1305, versioned modules (`crypto/encryption/v1.rs`) with a `schema_version` column for transparent migration on unseal
 - Password KDF: Argon2
-- Unseal transport: X25519 ephemeral key exchange
+- Unseal transport: X25519 ephemeral key exchange (`peers/operator/vault_gate/`); `x-wing` (hybrid PQ KEM) is available via `arbiter-crypto`
-- TLS: self-signed certificate (aws-lc-rs backend), fingerprint distributed via `ArbiterUrl`
+- TLS: self-signed certificate (rustls + aws-lc-rs, `prefer-post-quantum`), 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).
+Crypto modules are versioned by convention: `mod.rs` re-exports the current `vN`. Add a `v(N+1)` rather than editing an existing version in place.
+
+**Protocol:** gRPC with Protocol Buffers. `ArbiterUrl` 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:
+`arbiter-proto/build.rs` compiles `arbiter.proto`, `operator.proto`, `client.proto` and `evm.proto` (with their `shared/`, `operator/`, `client/` includes) on build:
 ```sh
 cd server && cargo build -p arbiter-proto
 ```
 
+Dart protobuf stubs are generated separately, from the repo root:
+```sh
+mise run codegen   # protoc --dart_out=grpc:useragent/lib/proto
+```
+
 ### Database Migrations
 
 ```sh
@@ -100,29 +131,46 @@ diesel migration generate <name> --migration-dir crates/arbiter-server/migration
 diesel migration run --migration-dir crates/arbiter-server/migrations
 ```
 
-## User Agent (Flutter + Rinf at `useragent/`)
+Pre-release policy: there is a single `init` migration and no deployed databases yet, so schema changes are made by editing that migration directly instead of stacking new ones. Regenerate `src/db/schema.rs` after changing it.
 
-The Flutter app uses [Rinf](https://rinf.cunarist.org) to call Rust code. The Rust logic lives in `useragent/native/hub/` as a separate crate that uses `arbiter-useragent` for the gRPC client.
+### Code Conventions
 
-Communication between Dart and Rust uses typed **signals** defined in `useragent/native/hub/src/signals/`. After modifying signal structs, regenerate Dart bindings:
+**`#[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:
 
-```sh
+- Methods that return `bool` indicating success/failure or validation state
-cd useragent && rinf gen
+- 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.
+
+## User Agent (Flutter + flutter_rust_bridge at `useragent/`)
+
+The Flutter app calls Rust through [flutter_rust_bridge](https://cjycode.com/flutter_rust_bridge/) 2.12.0. The Rust side is the `rust_lib_arbiter` crate at `useragent/rust/`; everything exposed to Dart is declared in `useragent/rust/src/api/` and lands in `useragent/lib/src/rust/` (see `useragent/flutter_rust_bridge.yaml`). Dart UI code is organised as `lib/features/`, `lib/screens/`, `lib/widgets/`, `lib/providers/`, `lib/theme/`, with routing in `lib/router.dart` (`router.gr.dart` is generated).
+
 ### Common Commands
 
 ```sh
 cd useragent
 
-# Run the app (macOS or Windows)
+# Run the app
 flutter run
 
-# Regenerate Rust↔Dart signal bindings
+# Regenerate Rust↔Dart bindings after editing rust/src/api/
-rinf gen
+mise run codegen        # flutter_rust_bridge_codegen generate
 
-# Analyze Dart code
+# Analyze Dart code (also run in CI)
 flutter analyze
 ```
 
-The Rinf Rust entry point is `useragent/native/hub/src/lib.rs`. It spawns actors defined in `useragent/native/hub/src/actors/` which handle Dart↔server communication via signals.
+Note: `app/` contains only stale generated Flutter artifacts and is not the application source.

CLAUDE.md

@@ -1,128 +1 @@
-# CLAUDE.md
+Refer to @AGENTS.md for instructions.
-
-This file provides guidance to Claude Code (claude.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
-- **`useragent/`** — 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-useragent` | Rust client library for the user agent 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.
-- **`KeyHolder`** — 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 user agents and SDK clients.
-- **`EvmActor`** — Handles EVM transaction policy enforcement and signing.
-
-Per-connection actors live under `actors/user_agent/` 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
-```
-
-## User Agent (Flutter + Rinf at `useragent/`)
-
-The Flutter app uses [Rinf](https://rinf.cunarist.org) to call Rust code. The Rust logic lives in `useragent/native/hub/` as a separate crate that uses `arbiter-useragent` for the gRPC client.
-
-Communication between Dart and Rust uses typed **signals** defined in `useragent/native/hub/src/signals/`. After modifying signal structs, regenerate Dart bindings:
-
-```sh
-cd useragent && rinf gen
-```
-
-### Common Commands
-
-```sh
-cd useragent
-
-# 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 `useragent/native/hub/src/lib.rs`. It spawns actors defined in `useragent/native/hub/src/actors/` which handle Dart↔server communication via signals.

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/",
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-    },
-    {
-      "name": "flutter_test",
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-      "languageVersion": "3.2"
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-      "packageUri": "lib/",
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-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/leak_tracker_testing-3.0.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.2"
-    },
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-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/lints-6.1.0",
-      "packageUri": "lib/",
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-      "languageVersion": "2.17"
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-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/path-1.9.1",
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-      "languageVersion": "3.4"
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-      "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"
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-      "packageUri": "lib/",
-      "languageVersion": "3.1"
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-      "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

@@ -9,7 +9,7 @@ Arbiter is a permissioned signing service for cryptocurrency wallets. It runs as
 
 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).
+- **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.
 
@@ -22,30 +22,32 @@ Arbiter distinguishes two kinds of peers:
 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).
+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 challenge with its private key and sends the signature back.
+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.
 
-### 2.2 User Agent Bootstrap
+Authentication challenges are per-connection, ephemeral values. They are not persisted in the peer tables, and peer records store no challenge state.
 
-On first run — when no User Agents are registered — the server generates a one-time bootstrap token. It is made available in two ways:
+### 2.2 Operator Bootstrap
 
-- **Local setup:** Written to `~/.arbiter/bootstrap_token` for automatic discovery by a co-located User Agent.
+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 User Agent must present this token alongside the standard challenge-response to complete registration.
+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 User Agent.
+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 User Agent 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.
+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
 
@@ -163,13 +165,13 @@ In both cases, committee formation is a coordinated process. Arbiter does not al
 
 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 a User Agent and the bootstrap token.
+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 a User Agent using the bootstrap token
+   - 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
@@ -191,8 +193,8 @@ The server proves its identity using TLS with a self-signed certificate. The TLS
 
 Peers verify the server by its **public key fingerprint**:
 
-- **User Agent (local):** Receives the fingerprint automatically through the bootstrap token.
+- **Operator (local):** Receives the fingerprint automatically through the bootstrap token.
-- **User Agent (remote) / SDK Client:** Must receive the fingerprint out-of-band.
+- **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.
 
@@ -229,11 +231,11 @@ On boot, the root key is encrypted and the server cannot perform any signing ope
 
 ### 6.2 Unseal Flow
 
-To transition to the **Unsealed** state, a User Agent must provide the password:
+To transition to the **Unsealed** state, an Operator must provide the password:
 
-1. The User Agent initiates an unseal request.
+1. The Operator 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.
+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.
@@ -255,7 +257,7 @@ See [IMPLEMENTATION.md](IMPLEMENTATION.md) for the current and planned memory pr
 ### 7.1 Fundamental Rules
 
 - SDK clients have **no access by default**.
-- Access is granted **explicitly** by a User Agent.
+- 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.
@@ -275,19 +277,19 @@ sequenceDiagram
     autonumber
     actor SDK as SDK Client
     participant Server
-    participant UA as User Agent
+    participant operator as Operator
 
     SDK->>Server: SignTransactionRequest
     Server->>Server: Resolve wallet and wallet visibility
     alt Visibility approval required
-        Server->>UA: Ask for wallet visibility approval
+        Server->>operator: Ask for wallet visibility approval
-        UA-->>Server: Vote result
+        operator-->>Server: Vote result
     end
     Server->>Server: Evaluate transaction
     Server->>Server: Load grant and limits context
     alt Grant approval required
-        Server->>UA: Ask for execution / grant approval
+        Server->>operator: Ask for execution / grant approval
-        UA-->>Server: Vote result
+        operator-->>Server: Vote result
         opt Create persistent grant
             Server->>Server: Create and store grant
         end

docs/IMPLEMENTATION.md

@@ -8,10 +8,10 @@ This document covers concrete technology choices and dependencies. For the archi
 
 ### Authentication Result Semantics
 
-Authentication no longer uses an implicit success-only response shape. Both `client` and `user-agent` return explicit auth status enums over the wire.
+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_USER_AGENTS_ONLINE`, or `INTERNAL`
+- **Client:** `AuthResult` may return `SUCCESS`, `INVALID_KEY`, `INVALID_SIGNATURE`, `APPROVAL_DENIED`, `NO_OPERATORS_ONLINE`, or `INTERNAL`
-- **User-agent:** `AuthResult` may return `SUCCESS`, `INVALID_KEY`, `INVALID_SIGNATURE`, `BOOTSTRAP_REQUIRED`, `TOKEN_INVALID`, 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:
 
@@ -22,63 +22,50 @@ Clients are expected to handle these status codes directly and present the concr
 
 ### New Client Approval
 
-When a client whose public key is not yet in the database connects, all connected user agents are asked to approve the connection. The first agent to respond determines the outcome; remaining requests are cancelled via a watch channel.
+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 --> D[Read nonce\nIncrement nonce in DB]
+    C -- yes --> G[Generate AuthChallenge]
-    D --> G
 
-    C -- no --> E[Ask all UserAgents:\nClientConnectionRequest]
+    C -- no --> E[Ask all Operators:\nClientConnectionRequest]
     E --> F{First response}
     F -- denied --> Z([Reject connection])
-    F -- approved --> F2[Cancel remaining\nUserAgent requests]
+    F -- approved --> F2[Cancel remaining\nOperator requests]
-    F2 --> F3[INSERT client\nnonce = 1]
+    F2 --> F3[INSERT client]
-    F3 --> G[Send AuthChallenge\nwith nonce]
+    F3 --> G
 
-    G --> H[Receive AuthChallengeSolution]
+    G --> H[Send AuthChallenge\ntimestamp + random bytes]
-    H --> I{Signature valid?}
+    H --> I[Receive AuthChallengeSolution]
-    I -- no --> Z
+    I --> K{Signature valid?}
-    I -- yes --> J([Session started])
+    K -- no --> Z
+    K -- yes --> J([Session started])
 ```
 
-### Known Issue: Concurrent Registration Race (TOCTOU)
+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.
 
-Two connections presenting the same previously-unknown public key can race through the approval flow simultaneously:
+The authentication schema stores peer identity, not replay counters:
 
-1. Both check the DB → neither is registered.
+- `program_client` stores the SDK client's public key, metadata binding, and timestamps.
-2. Both request approval from user agents → both receive approval.
+- `operator_client` stores the Operator public key and timestamps.
-3. Both `INSERT` the client record → the second insert silently overwrites the first, resetting the nonce.
+- Neither table stores an authentication nonce, and challenge generation does not update either table.
-
-This means the first connection's nonce is invalidated by the second, causing its challenge verification to fail. A fix requires either serialising new-client registration (e.g. an in-memory lock keyed on pubkey) or replacing the separate check + insert with an `INSERT OR IGNORE` / upsert guarded by a unique constraint on `public_key`.
-
-### Nonce Semantics
-
-The `program_client.nonce` column stores the **next usable nonce** — i.e. it is always one ahead of the nonce last issued in a challenge.
-
-- **New client:** inserted with `nonce = 1`; the first challenge is issued with `nonce = 0`.
-- **Existing client:** the current DB value is read and used as the challenge nonce, then immediately incremented within the same exclusive transaction, preventing replay.
 
 ---
 
 ## Cryptography
 
 ### Authentication
-- **Client protocol:** ed25519
+- **Client protocol:** ML-DSA
 
 ### User-Agent Authentication
 
-User-agent authentication supports multiple signature schemes because platform-provided "hardware-bound" keys do not expose a uniform algorithm across operating systems and hardware.
+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:** RSA, Ed25519, ECDSA (secp256k1)
+- **Supported schemes:** ML-DSA
-- **Why:** the user agent authenticates with keys backed by platform facilities, and those facilities differ by platform
+- **Why:** Secure Enclave (MacOS) support them natively, on other platforms we could emulate while they roll-out
-- **Apple Silicon Secure Enclave / Secure Element:** ECDSA-only in practice
-- **Windows Hello / TPM 2.0:** currently RSA-backed in our integration
-
-This is why the user-agent auth protocol carries an explicit `KeyType`, while the SDK client protocol remains fixed to ed25519.
 
 ### Encryption at Rest
 - **Scheme:** Symmetric AEAD — currently **XChaCha20-Poly1305**
@@ -99,7 +86,7 @@ This is why the user-agent auth protocol carries an explicit `KeyType`, while th
 
 ### Request Multiplexing
 
-Both `client` and `user-agent` connections support multiple in-flight requests over one gRPC bidi stream.
+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
@@ -154,7 +141,7 @@ flowchart TD
     L -- Yes --> M[Check grant limits]
     L -- No --> N[Start execution or grant voting flow]
 
-    N --> O{User-agent decision}
+    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]

mise.lock

@@ -1,55 +1,59 @@
 # @generated - this file is auto-generated by `mise lock` https://mise.jdx.dev/dev-tools/mise-lock.html
 
 [[tools.ast-grep]]
-version = "0.42.0"
+version = "0.42.1"
 backend = "aqua:ast-grep/ast-grep"
 
 [tools.ast-grep."platforms.linux-arm64"]
-checksum = "sha256:5c830eae8456569e2f7212434ed9c238f58dca412d76045418ed6d394a755836"
+checksum = "sha256:3ba383839044cf9817929435f5ce0027f91d06931e8efb32d942e58d73d92be5"
-url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-aarch64-unknown-linux-gnu.zip"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.1/app-aarch64-unknown-linux-gnu.zip"
 
 [tools.ast-grep."platforms.linux-arm64-musl"]
-checksum = "sha256:5c830eae8456569e2f7212434ed9c238f58dca412d76045418ed6d394a755836"
+checksum = "sha256:3ba383839044cf9817929435f5ce0027f91d06931e8efb32d942e58d73d92be5"
-url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-aarch64-unknown-linux-gnu.zip"
+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:e825a05603f0bcc4cd9076c4cc8c9abd6d008b7cd07d9aa3cc323ba4b8606651"
+checksum = "sha256:5de8b87cba67fc8dc3e239d54b6484802ad745a7ae3de76be4fe89661dc52657"
-url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-x86_64-unknown-linux-gnu.zip"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.1/app-x86_64-unknown-linux-gnu.zip"
 
 [tools.ast-grep."platforms.linux-x64-musl"]
-checksum = "sha256:e825a05603f0bcc4cd9076c4cc8c9abd6d008b7cd07d9aa3cc323ba4b8606651"
+checksum = "sha256:5de8b87cba67fc8dc3e239d54b6484802ad745a7ae3de76be4fe89661dc52657"
-url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-x86_64-unknown-linux-gnu.zip"
+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:fc300d5293b1c770a5aece03a8a193b92e71e87cec726c28096990691a582620"
+checksum = "sha256:c3961d8e8a4ee0ce2d0d98c7beeb168bb331cdc766b53630118a7b6c4fd39015"
-url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-aarch64-apple-darwin.zip"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.1/app-aarch64-apple-darwin.zip"
 
 [tools.ast-grep."platforms.macos-x64"]
-checksum = "sha256:979ffe611327056f4730a1ae71b0209b3b830f58b22c6ed194cda34f55400db2"
+checksum = "sha256:a038965bfd7fe44257c771cdf8918dc3467dd8ec0eef673b8b14f639b144cdbd"
-url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-x86_64-apple-darwin.zip"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.1/app-x86_64-apple-darwin.zip"
 
 [tools.ast-grep."platforms.windows-x64"]
-checksum = "sha256:55836fa1b2c65dc7d61615a4d9368622a0d2371a76d28b9a165e5a3ab6ae32a4"
+checksum = "sha256:fe34f631bb24c08ad146f92ca2a92971a53d179461b509fd8d32dc863bff9f83"
-url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-x86_64-pc-windows-msvc.zip"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.1/app-x86_64-pc-windows-msvc.zip"
 
 [[tools."cargo:cargo-audit"]]
 version = "0.22.1"
 backend = "cargo:cargo-audit"
 
 [[tools."cargo:cargo-edit"]]
-version = "0.13.9"
+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"]]
@@ -61,15 +65,19 @@ version = "0.10.2"
 backend = "cargo:cargo-vet"
 
 [[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"
+version = "3.41.7-stable"
 backend = "asdf:flutter"
 
 [[tools.protoc]]
@@ -105,37 +113,47 @@ checksum = "sha256:1ebd7c87baffb9f1c47169b640872bf5fb1e4408079c691af527be9561d8f
 url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-win64.zip"
 
 [[tools.python]]
-version = "3.14.3"
+version = "3.14.4"
 backend = "core:python"
 
 [tools.python."platforms.linux-arm64"]
-checksum = "sha256:53700338695e402a1a1fe22be4a41fbdacc70e22bb308a48eca8ed67cb7992be"
+checksum = "sha256:b8b597fdb2f8dccdc502c11947b60a4b65eb6bce79cfa60c7ccf9b6e8352c60a"
-url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-aarch64-unknown-linux-gnu-install_only_stripped.tar.gz"
+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 = "sha256:53700338695e402a1a1fe22be4a41fbdacc70e22bb308a48eca8ed67cb7992be"
+checksum = "sha256:b8b597fdb2f8dccdc502c11947b60a4b65eb6bce79cfa60c7ccf9b6e8352c60a"
-url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-aarch64-unknown-linux-gnu-install_only_stripped.tar.gz"
+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-x64"]
-checksum = "sha256:d7a9f970914bb4c88756fe3bdcc186d4feb90e9500e54f1db47dae4dc9687e39"
+checksum = "sha256:fe9a9c32d13870af632cbac3dfc7528ae53597e94472aa4c7d6a42e8166136cd"
-url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-x86_64-unknown-linux-gnu-install_only_stripped.tar.gz"
+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:d7a9f970914bb4c88756fe3bdcc186d4feb90e9500e54f1db47dae4dc9687e39"
+checksum = "sha256:fe9a9c32d13870af632cbac3dfc7528ae53597e94472aa4c7d6a42e8166136cd"
-url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-x86_64-unknown-linux-gnu-install_only_stripped.tar.gz"
+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.macos-arm64"]
-checksum = "sha256:c43aecde4a663aebff99b9b83da0efec506479f1c3f98331442f33d2c43501f9"
+checksum = "blake3:0314ec66e0f33ec04959583b5900bc8edae371a396aa96b8874e750d1fe936e6"
-url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-aarch64-apple-darwin-install_only_stripped.tar.gz"
+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 = "sha256:9ab41dbc2f100a2a45d1833b9c11165f51051c558b5213eda9a9731d5948a0c0"
+checksum = "sha256:d51250a32fa5d9f0799c7bcb71720c27b10a3afd4a7de288120f96085d508a5a"
-url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-x86_64-apple-darwin-install_only_stripped.tar.gz"
+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:bbe19034b35b0267176a7442575ae7dc6343480fd4d35598cb7700173d431e09"
+checksum = "sha256:a976991dcd085c1bb5d9a8084823a6bc8b7f9b079d8c432574a6ddd68c3a6fe1"
-url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-x86_64-pc-windows-msvc-install_only_stripped.tar.gz"
+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 = "1.98.1"
 backend = "core:rust"
+
+[tools.rust.options]
+components = "clippy,rust-analyzer"

mise.toml

@@ -1,17 +1,19 @@
 [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"}
+rust = { version = "latest", components = "clippy,rust-analyzer" }
-"cargo:cargo-features-manager" = "0.11.1"
+"cargo:cargo-features-manager" = "0.12.0"
-"cargo:cargo-nextest" = "0.9.126"
+"cargo:cargo-nextest" = "0.9.133"
 "cargo:cargo-shear" = "latest"
-"cargo:cargo-insta" = "1.46.3"
+"cargo:cargo-insta" = "1.47.2"
-python = "3.14.3"
+python = "3.14.4"
-ast-grep = "0.42.0"
+ast-grep = "0.42.1"
-"cargo:cargo-edit" = "0.13.9"
+"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']
@@ -20,3 +22,5 @@ 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/auth.proto

@@ -10,8 +10,8 @@ message AuthChallengeRequest {
 }
 
 message AuthChallenge {
-  bytes pubkey = 1;
+  uint64 timestamp_nanos = 1;
-  int32 nonce = 2;
+  bytes random = 2;
 }
 
 message AuthChallengeSolution {
@@ -24,7 +24,7 @@ enum AuthResult {
   AUTH_RESULT_INVALID_KEY = 2;
   AUTH_RESULT_INVALID_SIGNATURE = 3;
   AUTH_RESULT_APPROVAL_DENIED = 4;
-  AUTH_RESULT_NO_USER_AGENTS_ONLINE = 5;
+  AUTH_RESULT_NO_OPERATORS_ONLINE = 5;
   AUTH_RESULT_INTERNAL = 6;
 }
 

protobufs/evm.proto

@@ -75,7 +75,7 @@ message SpecificGrant {
   }
 }
 
-// --- UserAgent grant management ---
+// --- Operator grant management ---
 message EvmGrantCreateRequest {
   SharedSettings shared = 1;
   SpecificGrant specific = 2;

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

@@ -1,22 +1,15 @@
 syntax = "proto3";
 
-package arbiter.user_agent.auth;
+package arbiter.operator.auth;
-
-enum KeyType {
-  KEY_TYPE_UNSPECIFIED = 0;
-  KEY_TYPE_ED25519 = 1;
-  KEY_TYPE_ECDSA_SECP256K1 = 2;
-  KEY_TYPE_RSA = 3;
-}
 
 message AuthChallengeRequest {
   bytes pubkey = 1;
   optional string bootstrap_token = 2;
-  KeyType key_type = 3;
 }
 
 message AuthChallenge {
-  int32 nonce = 1;
+  uint64 timestamp_nanos = 1;
+  bytes random = 2;
 }
 
 message AuthChallengeSolution {

protobufs/operator/evm.proto

@@ -1,6 +1,6 @@
 syntax = "proto3";
 
-package arbiter.user_agent.evm;
+package arbiter.operator.evm;
 
 import "evm.proto";
 import "google/protobuf/empty.proto";

protobufs/operator/governance.proto

@@ -0,0 +1,136 @@
+syntax = "proto3";
+
+package arbiter.operator.governance;
+
+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         = 3;
+    ApproveServerUpdatePayload      approve_server_update       = 4;
+    ReplaceOperatorPayload          replace_operator            = 5;
+    UpdateShamirParametersPayload   update_shamir_parameters    = 6;
+    ApprovePersistentGrantPayload   approve_persistent_grant    = 7;
+    ApproveOneOffTransactionPayload approve_one_off_transaction = 8;
+  }
+  optional uint32 ttl_secs = 2;
+}
+
+message ReplaceOperatorPayload {
+  int32 old_operator_id = 1;
+  bytes new_pubkey      = 2;
+}
+
+message UpdateShamirParametersPayload {
+  uint32 new_n = 1;
+}
+
+message ApproveServerUpdatePayload {}
+
+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

@@ -1,6 +1,6 @@
 syntax = "proto3";
 
-package arbiter.user_agent.sdk_client;
+package arbiter.operator.sdk_client;
 
 import "shared/client.proto";
 import "google/protobuf/empty.proto";

protobufs/operator/vault/bootstrap.proto

@@ -0,0 +1,44 @@
+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 {
+  int32 recovery_operator_id = 1;
+  bytes passphrase            = 2;
+}
+
+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 +1,30 @@
+syntax = "proto3";
+
+package arbiter.operator.vault.rekey;
+
+message ContributePassphrase {
+  bytes passphrase = 1;
+}
+
+message ContributeRecoveryPassphrase {
+  int32 recovery_operator_id = 1;
+  bytes passphrase           = 2;
+}
+
+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

@@ -1,6 +1,6 @@
 syntax = "proto3";
 
-package arbiter.user_agent.vault.unseal;
+package arbiter.operator.vault.unseal;
 
 message UnsealStart {
   bytes client_pubkey = 1;
@@ -15,17 +15,29 @@ message UnsealEncryptedKey {
   bytes associated_data = 3;
 }
 
+message ContributePassphrase {
+  bytes passphrase = 1;
+}
+
+message ContributeRecoveryPassphrase {
+  int32 recovery_operator_id = 1;
+  bytes passphrase            = 2;
+}
+
 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;
+    UnsealStart                  start                          = 1;
-    UnsealEncryptedKey encrypted_key = 2;
+    UnsealEncryptedKey           encrypted_key                  = 2;
+    ContributePassphrase         contribute_passphrase          = 3;
+    ContributeRecoveryPassphrase contribute_recovery_passphrase = 4;
   }
 }
 

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/evm.proto

@@ -36,6 +36,10 @@ message GasLimitExceededViolation {
 }
 
 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;
@@ -43,6 +47,8 @@ message EvalViolation {
     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;
   }
 }
 

protobufs/shared/vault.proto

@@ -5,7 +5,8 @@ package arbiter.shared;
 enum VaultState {
   VAULT_STATE_UNSPECIFIED = 0;
   VAULT_STATE_UNBOOTSTRAPPED = 1;
-  VAULT_STATE_SEALED = 2;
+  VAULT_STATE_BOOSTRAPPING = 2;
-  VAULT_STATE_UNSEALED = 3;
+  VAULT_STATE_SEALED = 3;
-  VAULT_STATE_ERROR = 4;
+  VAULT_STATE_UNSEALED = 4;
+  VAULT_STATE_ERROR = 5;
 }

protobufs/user_agent.proto

@@ -1,28 +0,0 @@
-syntax = "proto3";
-
-package arbiter.user_agent;
-
-import "user_agent/auth.proto";
-import "user_agent/evm.proto";
-import "user_agent/sdk_client.proto";
-import "user_agent/vault/vault.proto";
-
-message UserAgentRequest {
-  int32 id = 16;
-  oneof payload {
-    auth.Request auth = 1;
-    vault.Request vault = 2;
-    evm.Request evm = 3;
-    sdk_client.Request sdk_client = 4;
-  }
-}
-
-message UserAgentResponse {
-  optional int32 id = 16;
-  oneof payload {
-    auth.Response auth = 1;
-    vault.Response vault = 2;
-    evm.Response evm = 3;
-    sdk_client.Response sdk_client = 4;
-  }
-}

protobufs/user_agent/vault/bootstrap.proto

@@ -1,24 +0,0 @@
-syntax = "proto3";
-
-package arbiter.user_agent.vault.bootstrap;
-
-message BootstrapEncryptedKey {
-  bytes nonce = 1;
-  bytes ciphertext = 2;
-  bytes associated_data = 3;
-}
-
-enum BootstrapResult {
-  BOOTSTRAP_RESULT_UNSPECIFIED = 0;
-  BOOTSTRAP_RESULT_SUCCESS = 1;
-  BOOTSTRAP_RESULT_ALREADY_BOOTSTRAPPED = 2;
-  BOOTSTRAP_RESULT_INVALID_KEY = 3;
-}
-
-message Request {
-  BootstrapEncryptedKey encrypted_key = 2;
-}
-
-message Response {
-  BootstrapResult result = 1;
-}

protobufs/user_agent/vault/vault.proto

@@ -1,24 +0,0 @@
-syntax = "proto3";
-
-package arbiter.user_agent.vault;
-
-import "google/protobuf/empty.proto";
-import "shared/vault.proto";
-import "user_agent/vault/bootstrap.proto";
-import "user_agent/vault/unseal.proto";
-
-message Request {
-  oneof payload {
-    google.protobuf.Empty query_state = 1;
-    unseal.Request unseal = 2;
-    bootstrap.Request bootstrap = 3;
-  }
-}
-
-message Response {
-  oneof payload {
-    arbiter.shared.VaultState state = 1;
-    unseal.Response unseal = 2;
-    bootstrap.Response bootstrap = 3;
-  }
-}

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

@@ -4,42 +4,170 @@ members = [
 ]
 resolver = "3"
 
-[workspace.lints.clippy]
-disallowed-methods = "deny"
-
 
 [workspace.dependencies]
-tonic = { version = "0.14.5", features = [
+alloy = "2.0.4"
-    "deflate",
+async-trait = "0.1.89"
-    "gzip",
+base64 = "0.22.1"
-    "tls-connect-info",
-    "zstd",
-] }
-tracing = "0.1.44"
-tokio = { version = "1.50.0", features = ["full"] }
-ed25519-dalek = { version = "3.0.0-pre.6", features = ["rand_core"] }
 chrono = { version = "0.4.44", features = ["serde"] }
-rand = "0.10.0"
+futures = "0.3.32"
-rustls = { version = "0.23.37", features = ["aws-lc-rs"] }
+k256 = { version = "0.13.4", features = ["ecdsa", "pkcs8"] }
+kameo = {git = "https://github.com/hdbg/kameo.git", rev = "3bbebac"}
+kameo_actors = {git = "https://github.com/hdbg/kameo.git", rev = "3bbebac"}
+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"] }
+rand = "0.10.1"
+rand_core = "0.10.1"
+rcgen = { version = "0.14.7", features = [ "aws_lc_rs",  "pem", "x509-parser", "zeroize" ], default-features = false }
+rstest = "0.26.1"
+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"
 thiserror = "2.0.18"
-async-trait = "0.1.89"
+tokio = { version = "1.52.1", features = ["full"] }
-futures = "0.3.32"
 tokio-stream = { version = "0.1.18", features = ["full"] }
-kameo = "0.19.2"
+tonic = { version = "0.14.5", features = [ "deflate", "gzip", "tls-connect-info", "zstd" ] }
-prost-types = { version = "0.14.3", features = ["chrono"] }
+tracing = "0.1.44"
 x25519-dalek = { version = "2.0.1", features = ["getrandom"] }
-rstest = "0.26.1"
+
-rustls-pki-types = "1.14.0"
+[workspace.lints.rust]
-alloy = "1.7.3"
+missing_unsafe_on_extern = "deny"
-rcgen = { version = "0.14.7", features = [
+unsafe_attr_outside_unsafe = "deny"
-    "aws_lc_rs",
+unsafe_op_in_unsafe_fn = "deny"
-    "pem",
+unstable_features = "deny"
-    "x509-parser",
+
-    "zeroize",
+deprecated_safe_2024 = "warn"
-], default-features = false }
+ffi_unwind_calls = "warn"
-k256 = { version = "0.13.4", features = ["ecdsa", "pkcs8"] }
+linker_messages = "warn"
-rsa = { version = "0.9", features = ["sha2"] }
+
-sha2 = "0.10"
+elided_lifetimes_in_paths = "warn"
-spki = "0.7"
+explicit_outlives_requirements = "warn"
-miette = { version = "7.6.0", features = ["fancy", "serde"] }
+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 {})
+too-many-lines = "allow" # this is a very common pattern in server code, and it's not always possible to break it down into smaller modules without hurting readability
+unused_async_trait_impl = "allow" # too pedantic
+
+# 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"
+integer_division = "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

server/clippy.toml

@@ -7,3 +7,22 @@ disallowed-methods = [
     { 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

server/crates/arbiter-client/Cargo.toml

@@ -13,14 +13,17 @@ 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
-ed25519-dalek.workspace = true
 thiserror.workspace = true
 http = "1.4.0"
-rustls-webpki = { version = "0.103.10", features = ["aws-lc-rs"] }
+rustls-webpki = { version = "0.103.13", features = ["aws-lc-rs"] }
 async-trait.workspace = true
-rand.workspace = true
+chrono.workspace = true
+
+[lib]
+doctest = false

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

@@ -1,5 +1,10 @@
+use crate::{
+    storage::StorageError,
+    transport::{ClientTransport, next_request_id},
+};
+use arbiter_crypto::authn::{self, CLIENT_CONTEXT, SigningKey};
 use arbiter_proto::{
-    ClientMetadata, format_challenge,
+    ClientMetadata,
     proto::{
         client::{
             ClientRequest,
@@ -14,35 +19,32 @@ use arbiter_proto::{
         shared::ClientInfo as ProtoClientInfo,
     },
 };
-use ed25519_dalek::Signer as _;
 
-use crate::{
+use chrono::DateTime;
-    storage::StorageError,
-    transport::{ClientTransport, next_request_id},
-};
 
 #[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("Client approval denied by User Agent")]
+    #[error("No Operators online to approve client")]
-    ApprovalDenied,
+    NoOperatorsOnline,
-
-    #[error("No User Agents online to approve client")]
-    NoUserAgentsOnline,
-
-    #[error("Unexpected auth response payload")]
-    UnexpectedAuthResponse,
 
     #[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::NoUserAgentsOnline => AuthError::NoUserAgentsOnline,
+        AuthResult::NoOperatorsOnline => AuthError::NoOperatorsOnline,
         AuthResult::Unspecified
         | AuthResult::Success
         | AuthResult::InvalidKey
@@ -54,14 +56,14 @@ fn map_auth_result(code: i32) -> AuthError {
 async fn send_auth_challenge_request(
     transport: &mut ClientTransport,
     metadata: ClientMetadata,
-    key: &ed25519_dalek::SigningKey,
+    key: &SigningKey,
-) -> std::result::Result<(), AuthError> {
+) -> Result<(), AuthError> {
     transport
         .send(ClientRequest {
             request_id: next_request_id(),
             payload: Some(ClientRequestPayload::Auth(proto_auth::Request {
                 payload: Some(AuthRequestPayload::ChallengeRequest(AuthChallengeRequest {
-                    pubkey: key.verifying_key().to_bytes().to_vec(),
+                    pubkey: key.public_key().to_bytes(),
                     client_info: Some(ProtoClientInfo {
                         name: metadata.name,
                         description: metadata.description,
@@ -76,7 +78,7 @@ async fn send_auth_challenge_request(
 
 async fn receive_auth_challenge(
     transport: &mut ClientTransport,
-) -> std::result::Result<AuthChallenge, AuthError> {
+) -> Result<AuthChallenge, AuthError> {
     let response = transport
         .recv()
         .await
@@ -95,11 +97,22 @@ async fn receive_auth_challenge(
 
 async fn send_auth_challenge_solution(
     transport: &mut ClientTransport,
-    key: &ed25519_dalek::SigningKey,
+    key: &SigningKey,
     challenge: AuthChallenge,
-) -> std::result::Result<(), AuthError> {
+) -> Result<(), AuthError> {
-    let challenge_payload = format_challenge(challenge.nonce, &challenge.pubkey);
+    let timestamp = DateTime::from_timestamp_nanos(challenge.timestamp_nanos.cast_signed());
-    let signature = key.sign(&challenge_payload).to_bytes().to_vec();
+    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, CLIENT_CONTEXT)
+        .map_err(|_| AuthError::UnexpectedAuthResponse)?
+        .to_bytes();
 
     transport
         .send(ClientRequest {
@@ -114,9 +127,7 @@ async fn send_auth_challenge_solution(
         .map_err(|_| AuthError::UnexpectedAuthResponse)
 }
 
-async fn receive_auth_confirmation(
+async fn receive_auth_confirmation(transport: &mut ClientTransport) -> Result<(), AuthError> {
-    transport: &mut ClientTransport,
-) -> std::result::Result<(), AuthError> {
     let response = transport
         .recv()
         .await
@@ -137,11 +148,11 @@ async fn receive_auth_confirmation(
     }
 }
 
-pub(crate) async fn authenticate(
+pub async fn authenticate(
     transport: &mut ClientTransport,
     metadata: ClientMetadata,
-    key: &ed25519_dalek::SigningKey,
+    key: &SigningKey,
-) -> std::result::Result<(), AuthError> {
+) -> 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?;

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

@@ -1,8 +1,8 @@
-use std::io::{self, Write};
-
 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...");
@@ -29,16 +29,16 @@ async fn main() {
         }
     };
 
-    println!("{:#?}", url);
+    println!("{url:#?}");
 
     let metadata = ClientMetadata {
-        name: "arbiter-client test_connect".to_string(),
+        name: "arbiter-client test_connect".to_owned(),
-        description: Some("Manual connection smoke test".to_string()),
+        description: Some("Manual connection smoke test".to_owned()),
-        version: Some(env!("CARGO_PKG_VERSION").to_string()),
+        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),
+        Err(err) => eprintln!("Failed to connect: {err:#?}"),
     }
 }

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

@@ -1,49 +1,55 @@
-use arbiter_proto::{
+#[cfg(feature = "evm")]
-    ClientMetadata, proto::arbiter_service_client::ArbiterServiceClient, url::ArbiterUrl,
+use crate::wallets::evm::ArbiterEvmWallet;
-};
-use std::sync::Arc;
-use tokio::sync::{Mutex, mpsc};
-use tokio_stream::wrappers::ReceiverStream;
-use tonic::transport::ClientTlsConfig;
-
 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,
+};
 
-#[cfg(feature = "evm")]
+use std::sync::Arc;
-use crate::wallets::evm::ArbiterEvmWallet;
+use tokio::sync::{Mutex, mpsc};
+use tokio_stream::wrappers::ReceiverStream;
+use tonic::transport::ClientTlsConfig;
 
 #[derive(Debug, thiserror::Error)]
-pub enum Error {
+pub enum ArbiterClientError {
-    #[error("gRPC error")]
+    #[error("Authentication error")]
-    Grpc(#[from] tonic::Status),
+    Authentication(#[from] AuthError),
 
     #[error("Could not establish connection")]
     Connection(#[from] tonic::transport::Error),
 
-    #[error("Invalid server URI")]
+    #[error("gRPC error")]
-    InvalidUri(#[from] http::uri::InvalidUri),
+    Grpc(#[from] tonic::Status),
 
     #[error("Invalid CA certificate")]
     InvalidCaCert(#[from] webpki::Error),
 
-    #[error("Authentication error")]
+    #[error("Invalid server URI")]
-    Authentication(#[from] AuthError),
+    InvalidUri(#[from] http::uri::InvalidUri),
 
     #[error("Storage error")]
     Storage(#[from] StorageError),
 }
 
 pub struct ArbiterClient {
-    #[allow(dead_code)]
+    #[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, Error> {
+    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
     }
@@ -52,7 +58,7 @@ impl ArbiterClient {
         url: ArbiterUrl,
         metadata: ClientMetadata,
         storage: &S,
-    ) -> Result<Self, Error> {
+    ) -> Result<Self, ArbiterClientError> {
         let key = storage.load_or_create()?;
         Self::connect_with_key(url, metadata, key).await
     }
@@ -60,8 +66,8 @@ impl ArbiterClient {
     pub async fn connect_with_key(
         url: ArbiterUrl,
         metadata: ClientMetadata,
-        key: ed25519_dalek::SigningKey,
+        key: SigningKey,
-    ) -> Result<Self, Error> {
+    ) -> Result<Self, ArbiterClientError> {
         let anchor = webpki::anchor_from_trusted_cert(&url.ca_cert)?.to_owned();
         let tls = ClientTlsConfig::new().trust_anchor(anchor);
 
@@ -88,7 +94,7 @@ impl ArbiterClient {
     }
 
     #[cfg(feature = "evm")]
-    pub async fn evm_wallets(&self) -> Result<Vec<ArbiterEvmWallet>, Error> {
+    pub async fn evm_wallets(&self) -> Result<Vec<ArbiterEvmWallet>, ArbiterClientError> {
         todo!("fetch EVM wallet list from server")
     }
 }

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

@@ -5,7 +5,7 @@ mod transport;
 pub mod wallets;
 
 pub use auth::AuthError;
-pub use client::{ArbiterClient, Error};
+pub use client::{ArbiterClient, ArbiterClientError};
 pub use storage::{FileSigningKeyStorage, SigningKeyStorage, StorageError};
 
 #[cfg(feature = "evm")]

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

@@ -1,17 +1,19 @@
+use arbiter_crypto::authn::SigningKey;
 use arbiter_proto::home_path;
+
 use std::path::{Path, PathBuf};
 
 #[derive(Debug, thiserror::Error)]
 pub enum StorageError {
-    #[error("I/O error")]
-    Io(#[from] std::io::Error),
-
     #[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) -> std::result::Result<ed25519_dalek::SigningKey, StorageError>;
+    fn load_or_create(&self) -> Result<SigningKey, StorageError>;
 }
 
 #[derive(Debug, Clone)]
@@ -20,17 +22,17 @@ pub struct FileSigningKeyStorage {
 }
 
 impl FileSigningKeyStorage {
-    pub const DEFAULT_FILE_NAME: &str = "sdk_client_ed25519.key";
+    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() -> std::result::Result<Self, StorageError> {
+    pub fn from_default_location() -> Result<Self, StorageError> {
         Ok(Self::new(home_path()?.join(Self::DEFAULT_FILE_NAME)))
     }
 
-    fn read_key(path: &Path) -> std::result::Result<ed25519_dalek::SigningKey, StorageError> {
+    fn read_key(path: &Path) -> Result<SigningKey, StorageError> {
         let bytes = std::fs::read(path)?;
         let raw: [u8; 32] =
             bytes
@@ -39,12 +41,12 @@ impl FileSigningKeyStorage {
                     expected: 32,
                     actual: v.len(),
                 })?;
-        Ok(ed25519_dalek::SigningKey::from_bytes(&raw))
+        Ok(SigningKey::from_seed(raw))
     }
 }
 
 impl SigningKeyStorage for FileSigningKeyStorage {
-    fn load_or_create(&self) -> std::result::Result<ed25519_dalek::SigningKey, StorageError> {
+    fn load_or_create(&self) -> Result<SigningKey, StorageError> {
         if let Some(parent) = self.path.parent() {
             std::fs::create_dir_all(parent)?;
         }
@@ -53,8 +55,8 @@ impl SigningKeyStorage for FileSigningKeyStorage {
             return Self::read_key(&self.path);
         }
 
-        let key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
+        let key = SigningKey::generate();
-        let raw_key = key.to_bytes();
+        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()
@@ -103,7 +105,7 @@ mod tests {
             .load_or_create()
             .expect("second load_or_create should read same key");
 
-        assert_eq!(key_a.to_bytes(), key_b.to_bytes());
+        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");
@@ -124,7 +126,7 @@ mod tests {
                 assert_eq!(expected, 32);
                 assert_eq!(actual, 31);
             }
-            other => panic!("unexpected error: {other:?}"),
+            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

@@ -1,16 +1,17 @@
 use arbiter_proto::proto::client::{ClientRequest, ClientResponse};
+
 use std::sync::atomic::{AtomicI32, Ordering};
 use tokio::sync::mpsc;
 
-pub(crate) const BUFFER_LENGTH: usize = 16;
+pub const BUFFER_LENGTH: usize = 16;
 static NEXT_REQUEST_ID: AtomicI32 = AtomicI32::new(1);
 
-pub(crate) fn next_request_id() -> i32 {
+pub fn next_request_id() -> i32 {
     NEXT_REQUEST_ID.fetch_add(1, Ordering::Relaxed)
 }
 
 #[derive(Debug, thiserror::Error)]
-pub(crate) enum ClientSignError {
+pub enum ClientSignError {
     #[error("Transport channel closed")]
     ChannelClosed,
 
@@ -18,27 +19,23 @@ pub(crate) enum ClientSignError {
     ConnectionClosed,
 }
 
-pub(crate) struct ClientTransport {
+pub struct ClientTransport {
     pub(crate) sender: mpsc::Sender<ClientRequest>,
     pub(crate) receiver: tonic::Streaming<ClientResponse>,
 }
 
 impl ClientTransport {
-    pub(crate) async fn send(
+    pub(crate) async fn send(&mut self, request: ClientRequest) -> Result<(), ClientSignError> {
-        &mut self,
-        request: ClientRequest,
-    ) -> std::result::Result<(), ClientSignError> {
         self.sender
             .send(request)
             .await
             .map_err(|_| ClientSignError::ChannelClosed)
     }
 
-    pub(crate) async fn recv(&mut self) -> std::result::Result<ClientResponse, ClientSignError> {
+    pub(crate) async fn recv(&mut self) -> Result<ClientResponse, ClientSignError> {
         match self.receiver.message().await {
             Ok(Some(resp)) => Ok(resp),
-            Ok(None) => Err(ClientSignError::ConnectionClosed),
+            Ok(None) | Err(_) => Err(ClientSignError::ConnectionClosed),
-            Err(_) => Err(ClientSignError::ConnectionClosed),
         }
     }
 }

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

@@ -1,13 +1,4 @@
-use alloy::{
+use crate::transport::{ClientTransport, next_request_id};
-    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;
-
 use arbiter_proto::proto::{
     client::{
         ClientRequest,
@@ -25,7 +16,15 @@ use arbiter_proto::proto::{
     shared::evm::TransactionEvalError,
 };
 
-use crate::transport::{ClientTransport, next_request_id};
+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.
 ///
@@ -59,7 +58,11 @@ pub struct ArbiterEvmWallet {
 }
 
 impl ArbiterEvmWallet {
-    pub(crate) fn new(transport: Arc<Mutex<ClientTransport>>, address: Address) -> Self {
+    #[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,
@@ -67,11 +70,12 @@ impl ArbiterEvmWallet {
         }
     }
 
-    pub fn address(&self) -> Address {
+    pub const fn address(&self) -> Address {
         self.address
     }
 
-    pub fn with_chain_id(mut self, chain_id: ChainId) -> Self {
+    #[must_use]
+    pub const fn with_chain_id(mut self, chain_id: ChainId) -> Self {
         self.chain_id = Some(chain_id);
         self
     }
@@ -146,6 +150,7 @@ impl TxSigner<Signature> for ArbiterEvmWallet {
             .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(

server/crates/arbiter-crypto/.gitignore

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

server/crates/arbiter-crypto/Cargo.toml

@@ -0,0 +1,25 @@
+[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}
+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"]
+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 +1,252 @@
+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;
+
+pub static CLIENT_CONTEXT: &[u8] = b"arbiter_client";
+pub static OPERATOR_CONTEXT: &[u8] = b"arbiter_operator";
+
+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: &[u8], signature: &Signature) -> bool {
+        let challenge = challenge.format();
+        self.0
+            .verify_with_context(&challenge, context, &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: &[u8]) -> Result<Signature, Error> {
+        self.0
+            .signing_key()
+            .sign_deterministic(message, context)
+            .map(Into::into)
+    }
+
+    pub fn sign_challenge(
+        &self,
+        challenge: &AuthChallenge,
+        context: &[u8],
+    ) -> 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::{CLIENT_CONTEXT, PublicKey, Signature, SigningKey, OPERATOR_CONTEXT};
+
+    #[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", CLIENT_CONTEXT)
+            .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, CLIENT_CONTEXT)
+            .expect("signature should be created");
+
+        assert!(public_key.verify(&challenge, CLIENT_CONTEXT, &signature));
+        assert!(!public_key.verify(&challenge, OPERATOR_CONTEXT, &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, CLIENT_CONTEXT)
+            .expect("signature should be created");
+
+        assert!(
+            restored
+                .public_key()
+                .verify(&challenge, CLIENT_CONTEXT, &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

@@ -1,7 +1,9 @@
-use std::ops::{Deref, DerefMut};
-use std::{any::type_name, fmt};
-
 use memsafe::MemSafe;
+use std::{
+    any::type_name,
+    fmt,
+    ops::{Deref, DerefMut},
+};
 
 pub trait SafeCellHandle<T> {
     type CellRead<'a>: Deref<Target = T>
@@ -29,7 +31,7 @@ pub trait SafeCellHandle<T> {
         let mut cell = Self::new(T::default());
         {
             let mut handle = cell.write();
-            f(handle.deref_mut());
+            f(&mut *handle);
         }
         cell
     }
@@ -105,6 +107,11 @@ impl<T> SafeCellHandle<T> for MemSafeCell<T> {
 
 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();
 }
 

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 = "0.14.5"
-prost = "0.14.3"
+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 = "0.14.5"
-protoc-bin-vendored = "3"
 
 [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

@@ -10,7 +10,7 @@ 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),
             ],

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

@@ -1,8 +1,6 @@
 pub mod transport;
 pub mod url;
 
-use base64::{Engine, prelude::BASE64_STANDARD};
-
 pub mod proto {
     tonic::include_proto!("arbiter");
 
@@ -14,30 +12,38 @@ pub mod proto {
         }
     }
 
-    pub mod user_agent {
+    pub mod operator {
-        tonic::include_proto!("arbiter.user_agent");
+        tonic::include_proto!("arbiter.operator");
 
         pub mod auth {
-            tonic::include_proto!("arbiter.user_agent.auth");
+            tonic::include_proto!("arbiter.operator.auth");
         }
 
         pub mod evm {
-            tonic::include_proto!("arbiter.user_agent.evm");
+            tonic::include_proto!("arbiter.operator.evm");
+        }
+
+        pub mod governance {
+            tonic::include_proto!("arbiter.operator.governance");
         }
 
         pub mod sdk_client {
-            tonic::include_proto!("arbiter.user_agent.sdk_client");
+            tonic::include_proto!("arbiter.operator.sdk_client");
         }
 
         pub mod vault {
-            tonic::include_proto!("arbiter.user_agent.vault");
+            tonic::include_proto!("arbiter.operator.vault");
 
             pub mod bootstrap {
-                tonic::include_proto!("arbiter.user_agent.vault.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.user_agent.vault.unseal");
+                tonic::include_proto!("arbiter.operator.vault.unseal");
             }
         }
     }
@@ -84,8 +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

@@ -54,10 +54,9 @@
 //!   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 std::marker::PhantomData;
-
 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)]
@@ -106,6 +105,36 @@ pub trait Receiver<Inbound>: Send + Sync {
 /// any built-in correlation mechanism between inbound and outbound items.
 pub trait Bi<Inbound, Outbound>: Sender<Outbound> + Receiver<Inbound> + Send + Sync {}
 
+#[async_trait]
+impl<T, Outbound> Sender<Outbound> for &mut T
+where
+    T: Sender<Outbound> + ?Sized,
+    Outbound: Send + 'static,
+{
+    async fn send(&mut self, item: Outbound) -> Result<(), Error> {
+        (**self).send(item).await
+    }
+}
+
+#[async_trait]
+impl<T, Inbound> Receiver<Inbound> for &mut T
+where
+    T: Receiver<Inbound> + ?Sized,
+    Inbound: Send + 'static,
+{
+    async fn recv(&mut self) -> Option<Inbound> {
+        (**self).recv().await
+    }
+}
+
+impl<T, Inbound, Outbound> Bi<Inbound, Outbound> for &mut T
+where
+    T: Bi<Inbound, Outbound> + ?Sized,
+    Inbound: Send + 'static,
+    Outbound: Send + 'static,
+{
+}
+
 pub trait SplittableBi<Inbound, Outbound>: Bi<Inbound, Outbound> {
     type Sender: Sender<Outbound>;
     type Receiver: Receiver<Inbound>;
@@ -161,3 +190,29 @@ where
 }
 
 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

@@ -1,10 +1,10 @@
+use super::{Bi, Receiver, Sender};
+
 use async_trait::async_trait;
 use futures::StreamExt;
 use tokio::sync::mpsc;
 use tokio_stream::wrappers::ReceiverStream;
 
-use super::{Bi, Receiver, Sender};
-
 pub struct GrpcSender<Outbound> {
     tx: mpsc::Sender<Result<Outbound, tonic::Status>>,
 }

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

@@ -1,7 +1,6 @@
-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";
@@ -105,7 +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

@@ -9,15 +9,16 @@ license = "Apache-2.0"
 workspace = true
 
 [dependencies]
-diesel = { version = "2.3.7", features = ["chrono", "returning_clauses_for_sqlite_3_35", "serde_json", "time", "uuid"] }
+diesel = { version = "2.3.9", features = ["chrono", "returning_clauses_for_sqlite_3_35", "serde_json", "time", "uuid"] }
-diesel-async = { version = "0.8.0", features = [
+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
@@ -26,34 +27,37 @@ tokio.workspace = true
 rustls.workspace = true
 smlang.workspace = true
 thiserror.workspace = true
-fatality = "0.1.1"
+diesel_migrations = { version = "2.3.2", features = ["sqlite"] }
-diesel_migrations = { version = "2.3.1", features = ["sqlite"] }
 async-trait.workspace = true
-secrecy = "0.10.3"
-futures.workspace = true
 tokio-stream.workspace = true
-dashmap = "6.1.0"
 rand.workspace = true
+rand_core.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 = "0.28.0", features = ["derive"] }
 pem = "3.0.6"
-k256.workspace = true
-rsa.workspace = true
 sha2.workspace = true
-spki.workspace = true
+hmac.workspace = true
 alloy.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 = "6.0.1"
 
 [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
+
+[lib]
+doctest = false

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

@@ -37,21 +37,32 @@ 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 integer
 ) STRICT;
 
 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,
-    key_type integer not null default(1), -- 1=Ed25519, 2=ECDSA(secp256k1)
     created_at integer not null default(unixepoch ('now')),
     updated_at integer not null default(unixepoch ('now'))
 ) STRICT;
-create unique index if not exists uniq_useragent_client_public_key on useragent_client (public_key, key_type);
+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,
@@ -73,7 +84,6 @@ create unique index if not exists uniq_metadata_binding_client on client_metadat
 
 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')),
@@ -191,3 +201,19 @@ create table if not exists evm_ether_transfer_grant_target (
 ) STRICT;
 
 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);

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

@@ -1,94 +1,164 @@
+use crate::{
+    actors::vault::events,
+    db::{self, schema},
+};
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_proto::{BOOTSTRAP_PATH, home_path};
+
 use diesel::QueryDsl;
 use diesel_async::RunQueryDsl;
-use kameo::{Actor, messages};
+use kameo::{
+    Actor,
+    actor::ActorRef,
+    messages,
+    prelude::{Context, Message},
+};
+use kameo_actors::message_bus::{MessageBus, Register};
+use rand::{RngExt, distr::Alphanumeric, rngs::SysRng};
+use rand_core::UnwrapErr;
+use std::path::{Path, PathBuf};
+use subtle::ConstantTimeEq as _;
+use tracing::warn;
 
-use rand::{RngExt, distr::Alphanumeric, make_rng, rngs::StdRng};
-use thiserror::Error;
-
-use crate::db::{self, DatabasePool, schema};
 const TOKEN_LENGTH: usize = 64;
 
-pub async fn generate_token() -> Result<String, std::io::Error> {
+async fn write_token_file(path: &Path, content: &str) -> Result<(), std::io::Error> {
-    let rng: StdRng = make_rng();
+    if let Some(parent) = path.parent() {
-
+        tokio::fs::create_dir_all(parent).await?;
-    let token: String = rng.sample_iter(Alphanumeric).take(TOKEN_LENGTH).fold(
+    }
-        Default::default(),
+    tokio::fs::write(path, content.as_bytes()).await?;
-        |mut accum, char| {
+    #[cfg(unix)]
-            accum += char.to_string().as_str();
+    {
-            accum
+        use std::os::unix::fs::PermissionsExt as _;
-        },
+        tokio::fs::set_permissions(path, std::fs::Permissions::from_mode(0o600)).await?;
-    );
+    }
-
+    Ok(())
-    tokio::fs::write(home_path()?.join(BOOTSTRAP_PATH), token.as_str()).await?;
-
-    Ok(token)
 }
 
-#[derive(Error, Debug)]
+async fn remove_token_file(path: &Path) {
+    match tokio::fs::remove_file(path).await {
+        Ok(()) => {}
+        Err(error) if error.kind() == std::io::ErrorKind::NotFound => {}
+        Err(error) => warn!(?error, ?path, "Failed to remove bootstrap token file"),
+    }
+}
+
+async fn generate_token(path: &Path) -> Result<SafeCell<[u8; TOKEN_LENGTH]>, std::io::Error> {
+    let mut cell = SafeCell::new([0u8; TOKEN_LENGTH]);
+    {
+        let mut buf = cell.write();
+        for (slot, byte) in buf
+            .iter_mut()
+            .zip(UnwrapErr(SysRng).sample_iter(Alphanumeric))
+        {
+            *slot = byte;
+        }
+    }
+    let token = cell.read_inline(|buf| String::from_utf8_lossy(buf.as_ref()).into_owned());
+    write_token_file(path, &token).await?;
+    Ok(cell)
+}
+
+#[derive(Debug, thiserror::Error)]
 pub enum Error {
     #[error("Database error: {0}")]
     Database(#[from] db::PoolError),
-
-    #[error("Database query error: {0}")]
-    Query(#[from] diesel::result::Error),
-
     #[error("I/O error: {0}")]
     Io(#[from] std::io::Error),
+    #[error("Database query error: {0}")]
+    Query(#[from] diesel::result::Error),
 }
 
-#[derive(Actor)]
+/// Custodian of the one-time bootstrap token.
+///
+/// The token authorises registering operator identities before the vault
+/// exists. A Shamir committee needs every member registered before it can be
+/// declared, so the token stays valid across several registrations and is
+/// retired by the `Bootstrapped` event rather than by first use, whichever
+/// bootstrap path fired it.
+///
+/// Every daemon start mints a fresh token and overwrites the file: a token
+/// handed out by an earlier run is dead.
 pub struct Bootstrapper {
-    token: Option<String>,
+    token: Option<SafeCell<[u8; TOKEN_LENGTH]>>,
+    token_path: Option<PathBuf>,
+    events: ActorRef<MessageBus>,
+}
+
+impl Actor for Bootstrapper {
+    type Args = Self;
+    type Error = std::convert::Infallible;
+
+    async fn on_start(args: Self::Args, actor_ref: ActorRef<Self>) -> Result<Self, Self::Error> {
+        let _ = args
+            .events
+            .tell(Register(actor_ref.recipient::<events::Bootstrapped>()))
+            .await;
+        Ok(args)
+    }
 }
 
 impl Bootstrapper {
-    pub async fn new(db: &DatabasePool) -> Result<Self, Error> {
+    pub async fn new(db: &db::DatabasePool, events: ActorRef<MessageBus>) -> Result<Self, Error> {
+        let path = home_path()?.join(BOOTSTRAP_PATH);
         let mut conn = db.get().await?;
 
-        let row_count: i64 = schema::useragent_client::table
+        let bootstrapped = schema::arbiter_settings::table
-            .count()
+            .select(schema::arbiter_settings::root_key_id)
-            .get_result(&mut conn)
+            .first::<Option<i32>>(&mut conn)
-            .await?;
+            .await?
-
+            .is_some();
-        drop(conn);
+        if bootstrapped {
-
+            // A token file can outlive the bootstrap that made it obsolete:
-        let token = if row_count == 0 {
+            // the daemon may have been killed before the event was handled.
-            let token = generate_token().await?;
+            remove_token_file(&path).await;
-            Some(token)
+            return Ok(Self {
-        } else {
+                token: None,
-            None
+                token_path: None,
-        };
+                events,
-
+            });
-        Ok(Self { token })
-    }
-}
-
-#[messages]
-impl Bootstrapper {
-    #[message]
-    pub fn is_correct_token(&self, token: String) -> bool {
-        match &self.token {
-            Some(expected) => *expected == token,
-            None => false,
         }
+
+        Ok(Self {
+            token: Some(generate_token(&path).await?),
+            token_path: Some(path),
+            events,
+        })
     }
 
-    #[message]
+    async fn forget(&mut self) {
-    pub fn consume_token(&mut self, token: String) -> bool {
+        self.token = None;
-        if self.is_correct_token(token) {
+        if let Some(path) = self.token_path.take() {
-            self.token = None;
+            remove_token_file(&path).await;
-            true
-        } else {
-            false
         }
     }
 }
 
+impl Message<events::Bootstrapped> for Bootstrapper {
+    type Reply = ();
+
+    async fn handle(
+        &mut self,
+        _: events::Bootstrapped,
+        _ctx: &mut Context<Self, Self::Reply>,
+    ) -> Self::Reply {
+        self.forget().await;
+    }
+}
+    
 #[messages]
 impl Bootstrapper {
     #[message]
-    pub fn get_token(&self) -> Option<String> {
+    pub fn verify_token(&mut self, token: Vec<u8>) -> bool {
-        self.token.clone()
+        self.token.as_mut().is_some_and(|expected| {
+            expected.read_inline(|bytes| bool::from(bytes.as_ref().ct_eq(token.as_slice())))
+        })
+    }
+
+    #[message]
+    pub fn get_token(&mut self) -> Option<String> {
+        self.token
+            .as_mut()
+            .map(|cell| cell.read_inline(|buf| String::from_utf8_lossy(buf.as_ref()).into_owned()))
     }
 }

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

@@ -1,329 +0,0 @@
-use arbiter_proto::{
-    ClientMetadata, format_challenge,
-    transport::{Bi, expect_message},
-};
-use chrono::Utc;
-use diesel::{
-    ExpressionMethods as _, OptionalExtension as _, QueryDsl as _, SelectableHelper as _,
-    dsl::insert_into, update,
-};
-use diesel_async::RunQueryDsl as _;
-use ed25519_dalek::{Signature, VerifyingKey};
-use kameo::error::SendError;
-use tracing::error;
-
-use crate::{
-    actors::{
-        client::{ClientConnection, ClientProfile},
-        flow_coordinator::{self, RequestClientApproval},
-    },
-    db::{
-        self,
-        models::{ProgramClientMetadata, SqliteTimestamp},
-        schema::program_client,
-    },
-};
-
-#[derive(thiserror::Error, Debug, Clone, PartialEq, Eq)]
-pub enum Error {
-    #[error("Database pool unavailable")]
-    DatabasePoolUnavailable,
-    #[error("Database operation failed")]
-    DatabaseOperationFailed,
-    #[error("Invalid challenge solution")]
-    InvalidChallengeSolution,
-    #[error("Client approval request failed")]
-    ApproveError(#[from] ApproveError),
-    #[error("Transport error")]
-    Transport,
-}
-
-#[derive(thiserror::Error, Debug, Clone, PartialEq, Eq)]
-pub enum ApproveError {
-    #[error("Internal error")]
-    Internal,
-    #[error("Client connection denied by user agents")]
-    Denied,
-    #[error("Upstream error: {0}")]
-    Upstream(flow_coordinator::ApprovalError),
-}
-
-#[derive(Debug, Clone)]
-pub enum Inbound {
-    AuthChallengeRequest {
-        pubkey: VerifyingKey,
-        metadata: ClientMetadata,
-    },
-    AuthChallengeSolution {
-        signature: Signature,
-    },
-}
-
-#[derive(Debug, Clone)]
-pub enum Outbound {
-    AuthChallenge { pubkey: VerifyingKey, nonce: i32 },
-    AuthSuccess,
-}
-
-pub struct ClientInfo {
-    pub id: i32,
-    pub current_nonce: i32,
-}
-
-/// Atomically reads and increments the nonce for a known client.
-/// Returns `None` if the pubkey is not registered.
-async fn get_client_and_nonce(
-    db: &db::DatabasePool,
-    pubkey: &VerifyingKey,
-) -> Result<Option<ClientInfo>, Error> {
-    let pubkey_bytes = pubkey.as_bytes().to_vec();
-
-    let mut conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::DatabasePoolUnavailable
-    })?;
-
-    conn.exclusive_transaction(|conn| {
-        Box::pin(async move {
-            let Some((client_id, current_nonce)) = program_client::table
-                .filter(program_client::public_key.eq(&pubkey_bytes))
-                .select((program_client::id, program_client::nonce))
-                .first::<(i32, i32)>(conn)
-                .await
-                .optional()?
-            else {
-                return Result::<_, diesel::result::Error>::Ok(None);
-            };
-
-            update(program_client::table)
-                .filter(program_client::public_key.eq(&pubkey_bytes))
-                .set(program_client::nonce.eq(current_nonce + 1))
-                .execute(conn)
-                .await?;
-
-            Ok(Some(ClientInfo {
-                id: client_id,
-                current_nonce,
-            }))
-        })
-    })
-    .await
-    .map_err(|e| {
-        error!(error = ?e, "Database error");
-        Error::DatabaseOperationFailed
-    })
-}
-
-async fn approve_new_client(
-    actors: &crate::actors::GlobalActors,
-    profile: ClientProfile,
-) -> Result<(), Error> {
-    let result = actors
-        .flow_coordinator
-        .ask(RequestClientApproval { client: profile })
-        .await;
-
-    match result {
-        Ok(true) => Ok(()),
-        Ok(false) => Err(Error::ApproveError(ApproveError::Denied)),
-        Err(SendError::HandlerError(e)) => {
-            error!(error = ?e, "Approval upstream error");
-            Err(Error::ApproveError(ApproveError::Upstream(e)))
-        }
-        Err(e) => {
-            error!(error = ?e, "Approval request to flow coordinator failed");
-            Err(Error::ApproveError(ApproveError::Internal))
-        }
-    }
-}
-
-async fn insert_client(
-    db: &db::DatabasePool,
-    pubkey: &VerifyingKey,
-    metadata: &ClientMetadata,
-) -> Result<i32, Error> {
-    use crate::db::schema::{client_metadata, program_client};
-    let mut conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::DatabasePoolUnavailable
-    })?;
-
-    let metadata_id = insert_into(client_metadata::table)
-        .values((
-            client_metadata::name.eq(&metadata.name),
-            client_metadata::description.eq(&metadata.description),
-            client_metadata::version.eq(&metadata.version),
-        ))
-        .returning(client_metadata::id)
-        .get_result::<i32>(&mut conn)
-        .await
-        .map_err(|e| {
-            error!(error = ?e, "Failed to insert client metadata");
-            Error::DatabaseOperationFailed
-        })?;
-
-    let client_id = insert_into(program_client::table)
-        .values((
-            program_client::public_key.eq(pubkey.as_bytes().to_vec()),
-            program_client::metadata_id.eq(metadata_id),
-            program_client::nonce.eq(1), // pre-incremented; challenge uses 0
-        ))
-        .on_conflict_do_nothing()
-        .returning(program_client::id)
-        .get_result::<i32>(&mut conn)
-        .await
-        .map_err(|e| {
-            error!(error = ?e, "Failed to insert client metadata");
-            Error::DatabaseOperationFailed
-        })?;
-
-    Ok(client_id)
-}
-
-async fn sync_client_metadata(
-    db: &db::DatabasePool,
-    client_id: i32,
-    metadata: &ClientMetadata,
-) -> Result<(), Error> {
-    use crate::db::schema::{client_metadata, client_metadata_history};
-
-    let now = SqliteTimestamp(Utc::now());
-
-    let mut conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::DatabasePoolUnavailable
-    })?;
-
-    conn.exclusive_transaction(|conn| {
-        let metadata = metadata.clone();
-        Box::pin(async move {
-            let (current_metadata_id, current): (i32, ProgramClientMetadata) =
-                program_client::table
-                    .find(client_id)
-                    .inner_join(client_metadata::table)
-                    .select((
-                        program_client::metadata_id,
-                        ProgramClientMetadata::as_select(),
-                    ))
-                    .first(conn)
-                    .await?;
-
-            let unchanged = current.name == metadata.name
-                && current.description == metadata.description
-                && current.version == metadata.version;
-            if unchanged {
-                return Ok(());
-            }
-
-            insert_into(client_metadata_history::table)
-                .values((
-                    client_metadata_history::metadata_id.eq(current_metadata_id),
-                    client_metadata_history::client_id.eq(client_id),
-                ))
-                .execute(conn)
-                .await?;
-
-            let metadata_id = insert_into(client_metadata::table)
-                .values((
-                    client_metadata::name.eq(&metadata.name),
-                    client_metadata::description.eq(&metadata.description),
-                    client_metadata::version.eq(&metadata.version),
-                ))
-                .returning(client_metadata::id)
-                .get_result::<i32>(conn)
-                .await?;
-
-            update(program_client::table.find(client_id))
-                .set((
-                    program_client::metadata_id.eq(metadata_id),
-                    program_client::updated_at.eq(now),
-                ))
-                .execute(conn)
-                .await?;
-
-            Ok::<(), diesel::result::Error>(())
-        })
-    })
-    .await
-    .map_err(|e| {
-        error!(error = ?e, "Database error");
-        Error::DatabaseOperationFailed
-    })
-}
-
-async fn challenge_client<T>(
-    transport: &mut T,
-    pubkey: VerifyingKey,
-    nonce: i32,
-) -> Result<(), Error>
-where
-    T: Bi<Inbound, Result<Outbound, Error>> + ?Sized,
-{
-    transport
-        .send(Ok(Outbound::AuthChallenge { pubkey, nonce }))
-        .await
-        .map_err(|e| {
-            error!(error = ?e, "Failed to send auth challenge");
-            Error::Transport
-        })?;
-
-    let signature = expect_message(transport, |req: Inbound| match req {
-        Inbound::AuthChallengeSolution { signature } => Some(signature),
-        _ => None,
-    })
-    .await
-    .map_err(|e| {
-        error!(error = ?e, "Failed to receive challenge solution");
-        Error::Transport
-    })?;
-
-    let formatted = format_challenge(nonce, pubkey.as_bytes());
-
-    pubkey.verify_strict(&formatted, &signature).map_err(|_| {
-        error!("Challenge solution verification failed");
-        Error::InvalidChallengeSolution
-    })?;
-
-    Ok(())
-}
-
-pub async fn authenticate<T>(props: &mut ClientConnection, transport: &mut T) -> Result<i32, Error>
-where
-    T: Bi<Inbound, Result<Outbound, Error>> + Send + ?Sized,
-{
-    let Some(Inbound::AuthChallengeRequest { pubkey, metadata }) = transport.recv().await else {
-        return Err(Error::Transport);
-    };
-
-    let info = match get_client_and_nonce(&props.db, &pubkey).await? {
-        Some(nonce) => nonce,
-        None => {
-            approve_new_client(
-                &props.actors,
-                ClientProfile {
-                    pubkey,
-                    metadata: metadata.clone(),
-                },
-            )
-            .await?;
-            let client_id = insert_client(&props.db, &pubkey, &metadata).await?;
-            ClientInfo {
-                id: client_id,
-                current_nonce: 0,
-            }
-        }
-    };
-
-    sync_client_metadata(&props.db, info.id, &metadata).await?;
-    challenge_client(transport, pubkey, info.current_nonce).await?;
-
-    transport
-        .send(Ok(Outbound::AuthSuccess))
-        .await
-        .map_err(|e| {
-            error!(error = ?e, "Failed to send auth success");
-            Error::Transport
-        })?;
-
-    Ok(info.id)
-}

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

@@ -1,43 +1,67 @@
-use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
+use crate::{
+    actors::vault::{CreateNew, Decrypt, Vault},
+    crypto::integrity::{self, Integrable},
+    db::{
+        DatabaseError, DatabasePool,
+        models::{self, EvmWalletId},
+        schema,
+    },
+    evm::{
+        self, ListError, RunKind,
+        policies::{
+            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};
 use rand::{SeedableRng, rng, rngs::StdRng};
-
+use tracing::error;
-use crate::{
-    actors::keyholder::{CreateNew, Decrypt, KeyHolder},
-    db::{
-        DatabaseError, DatabasePool,
-        models::{self, SqliteTimestamp},
-        schema,
-    },
-    evm::{
-        self, RunKind,
-        policies::{
-            FullGrant, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
-            ether_transfer::EtherTransfer, token_transfers::TokenTransfer,
-        },
-    },
-    safe_cell::{SafeCell, SafeCellHandle as _},
-};
 
 pub use crate::evm::safe_signer;
 
+/// Integrity guard that binds a wallet's encrypted key ID to its Ethereum address.
+/// Both fields are included in the HMAC — swapping `aead_encrypted_id` in the DB
+/// invalidates the envelope MAC, and the AEAD ciphertext is also bound to `address`
+/// as AAD, so decryption fails too.
+#[derive(arbiter_macros::Hashable)]
+struct EvmWalletIntegrity {
+    aead_encrypted_id: i32,
+    address: Address,
+}
+
+impl Integrable for EvmWalletIntegrity {
+    const KIND: &'static str = "evm_wallet";
+}
+
 #[derive(Debug, thiserror::Error)]
 pub enum SignTransactionError {
     #[error("Wallet not found")]
     WalletNotFound,
 
+    #[error("Decrypted key does not match requested wallet address")]
+    KeyAddressMismatch,
+
+    #[error("Internal signing error")]
+    Internal,
+
     #[error("Database error: {0}")]
     Database(#[from] DatabaseError),
 
-    #[error("Keyholder error: {0}")]
+    #[error("Vault error: {0}")]
-    Keyholder(#[from] crate::actors::keyholder::Error),
+    Vault(#[from] crate::actors::vault::Error),
 
-    #[error("Keyholder mailbox error")]
+    #[error("Vault mailbox error")]
-    KeyholderSend,
+    VaultSend,
 
     #[error("Signing error: {0}")]
     Signing(#[from] alloy::signers::Error),
@@ -48,32 +72,41 @@ pub enum SignTransactionError {
 
 #[derive(Debug, thiserror::Error)]
 pub enum Error {
-    #[error("Keyholder error: {0}")]
+    #[error("Vault error: {0}")]
-    Keyholder(#[from] crate::actors::keyholder::Error),
+    Vault(#[from] crate::actors::vault::Error),
 
-    #[error("Keyholder mailbox error")]
+    #[error("Vault mailbox error")]
-    KeyholderSend,
+    VaultSend,
 
     #[error("Database error: {0}")]
     Database(#[from] DatabaseError),
+
+    #[error("Integrity violation: {0}")]
+    Integrity(#[from] integrity::Error),
+}
+
+impl From<diesel::result::Error> for Error {
+    fn from(e: diesel::result::Error) -> Self {
+        Self::Database(DatabaseError::from(e))
+    }
 }
 
 #[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());
+        let engine = evm::Engine::new(db.clone(), vault.clone());
         Self {
-            keyholder,
+            vault,
             db,
             rng,
             engine,
@@ -90,27 +123,46 @@ impl EvmActor {
         let plaintext = key_cell.read_inline(|reader| SafeCell::new(reader.to_vec()));
 
         let aead_id: i32 = self
-            .keyholder
+            .vault
-            .ask(CreateNew { plaintext })
+            .ask(CreateNew {
+                plaintext,
+                aad: address.as_slice().to_vec(),
+            })
             .await
-            .map_err(|_| Error::KeyholderSend)?;
+            .map_err(|_| Error::VaultSend)?;
 
         let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
-        let wallet_id = insert_into(schema::evm_wallet::table)
+        let wallet_id = conn
-            .values(&models::NewEvmWallet {
+            .exclusive_transaction(async |conn| {
-                address: address.as_slice().to_vec(),
+                let wallet_id: i32 = insert_into(schema::evm_wallet::table)
-                aead_encrypted_id: aead_id,
+                    .values(&models::NewEvmWallet {
+                        address: address.as_slice().to_vec(),
+                        aead_encrypted_id: aead_id,
+                    })
+                    .returning(schema::evm_wallet::id)
+                    .get_result(conn)
+                    .await
+                    .map_err(DatabaseError::from)
+                    .map_err(Error::Database)?;
+
+                integrity::sign_entity(
+                    conn,
+                    &self.vault,
+                    &EvmWalletIntegrity { address, aead_encrypted_id: aead_id },
+                    wallet_id,
+                )
+                .await
+                .map_err(Error::Integrity)?;
+
+                Ok::<i32, Error>(wallet_id)
             })
-            .returning(schema::evm_wallet::id)
+            .await?;
-            .get_result(&mut conn)
-            .await
-            .map_err(DatabaseError::from)?;
 
         Ok((wallet_id, address))
     }
 
     #[message]
-    pub async fn list_wallets(&self) -> Result<Vec<(i32, Address)>, Error> {
+    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())
@@ -128,50 +180,49 @@ impl EvmActor {
 #[messages]
 impl EvmActor {
     #[message]
-    pub async fn useragent_create_grant(
+    pub async fn operator_create_grant(
         &mut self,
         basic: SharedGrantSettings,
         grant: SpecificGrant,
-    ) -> Result<i32, DatabaseError> {
+    ) -> Result<i32, Error> {
         match grant {
-            SpecificGrant::EtherTransfer(settings) => {
+            SpecificGrant::EtherTransfer(settings) => self
-                self.engine
+                .engine
-                    .create_grant::<EtherTransfer>(FullGrant {
+                .create_grant::<EtherTransfer>(CombinedSettings {
-                        basic,
+                    shared: basic,
-                        specific: settings,
+                    specific: settings,
-                    })
+                })
-                    .await
+                .await
-            }
+                .map_err(Error::from),
-            SpecificGrant::TokenTransfer(settings) => {
+            SpecificGrant::TokenTransfer(settings) => self
-                self.engine
+                .engine
-                    .create_grant::<TokenTransfer>(FullGrant {
+                .create_grant::<TokenTransfer>(CombinedSettings {
-                        basic,
+                    shared: basic,
-                        specific: settings,
+                    specific: settings,
-                    })
+                })
-                    .await
+                .await
-            }
+                .map_err(Error::from),
         }
     }
 
     #[message]
-    pub async fn useragent_delete_grant(&mut self, grant_id: i32) -> Result<(), Error> {
+    pub async fn useragent_delete_grant(
-        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
+        &mut self,
-        diesel::update(schema::evm_basic_grant::table)
+        grant_id: i32,
-            .filter(schema::evm_basic_grant::id.eq(grant_id))
+    ) -> Result<(), Error> {
-            .set(schema::evm_basic_grant::revoked_at.eq(SqliteTimestamp::now()))
+        self.engine
-            .execute(&mut conn)
+            .revoke_grant(grant_id)
             .await
-            .map_err(DatabaseError::from)?;
+            .map_err(Error::from)
-        Ok(())
     }
 
     #[message]
-    pub async fn useragent_list_grants(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
+    pub async fn operator_list_grants(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
-        Ok(self
+        match self.engine.list_all_grants().await {
-            .engine
+            Ok(grants) => Ok(grants),
-            .list_all_grants()
+            Err(ListError::Database(db_err)) => Err(Error::Database(db_err)),
-            .await
+            Err(ListError::Integrity(integrity_err)) => Err(Error::Integrity(integrity_err)),
-            .map_err(DatabaseError::from)?)
+        }
     }
 
     #[message]
@@ -236,21 +287,55 @@ impl EvmActor {
             .ok_or(SignTransactionError::WalletNotFound)?;
         drop(conn);
 
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
+        let attestation = integrity::verify_entity(
+            &mut conn,
+            &self.vault,
+            &EvmWalletIntegrity {
+                address: wallet_address,
+                aead_encrypted_id: wallet.aead_encrypted_id,
+            },
+            wallet.id.to_raw(),
+        )
+        .await
+        .map_err(|e| {
+            error!(?e, ?wallet.id, "EVM wallet integrity check failed");
+            SignTransactionError::Internal
+        })?;
+        drop(conn);
+
+        if attestation != integrity::AttestationStatus::Attested {
+            error!(
+                ?wallet.id,
+                "EVM wallet integrity unavailable; refusing to sign"
+            );
+            return Err(SignTransactionError::Internal);
+        }
+
         let raw_key: SafeCell<Vec<u8>> = self
-            .keyholder
+            .vault
             .ask(Decrypt {
                 aead_id: wallet.aead_encrypted_id,
+                aad: wallet.address.clone(),
             })
             .await
-            .map_err(|_| SignTransactionError::KeyholderSend)?;
+            .map_err(|_| SignTransactionError::VaultSend)?;
 
         let signer = safe_signer::SafeSigner::from_cell(raw_key)?;
 
+        if signer.address() != wallet_address {
+            error!(
+                expected = %wallet_address,
+                actual = %signer.address(),
+                "Decrypted private key address does not match requested wallet"
+            );
+            return Err(SignTransactionError::KeyAddressMismatch);
+        }
+
         self.engine
             .evaluate_transaction(wallet_access, transaction.clone(), RunKind::Execution)
             .await?;
 
-        use alloy::network::TxSignerSync as _;
         Ok(signer.sign_transaction_sync(&mut transaction)?)
     }
 }

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

@@ -1,25 +1,28 @@
-use std::ops::ControlFlow;
+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, time::Duration};
 
-use crate::actors::{
+const APPROVAL_TIMEOUT: Duration = Duration::from_secs(30);
-    client::ClientProfile,
-    flow_coordinator::ApprovalError,
-    user_agent::{UserAgentSession, session::BeginNewClientApproval},
-};
 
 pub struct Args {
     pub client: ClientProfile,
-    pub user_agents: Vec<ActorRef<UserAgentSession>>,
+    pub operators: Vec<ActorRef<OperatorSession>>,
     pub reply: ReplySender<Result<bool, ApprovalError>>,
 }
 
 pub struct ClientApprovalController {
-    /// Number of UAs that have not yet responded (approval or denial) or died.
+    /// Number of operators that have not yet responded (approval or denial) or died.
     pending: usize,
     /// Number of approvals received so far.
     approved: usize,
@@ -41,20 +44,21 @@ impl Actor for ClientApprovalController {
     async fn on_start(
         Args {
             client,
-            mut user_agents,
+            operators,
             reply,
         }: Self::Args,
         actor_ref: ActorRef<Self>,
     ) -> Result<Self, Self::Error> {
         let this = Self {
-            pending: user_agents.len(),
+            pending: operators.len(),
             approved: 0,
             reply: Some(reply),
         };
 
-        for user_agent in user_agents.drain(..) {
+        for operator in operators {
-            actor_ref.link(&user_agent).await;
+            actor_ref.link(&operator).await;
-            let _ = user_agent
+
+            let _ = operator
                 .tell(BeginNewClientApproval {
                     client: client.clone(),
                     controller: actor_ref.clone(),
@@ -62,6 +66,14 @@ impl Actor for ClientApprovalController {
                 .await;
         }
 
+        let weak = actor_ref.downgrade();
+        tokio::spawn(async move {
+            tokio::time::sleep(APPROVAL_TIMEOUT).await;
+            if let Some(r) = weak.upgrade() {
+                let _ = r.tell(OnApprovalTimeout {}).await;
+            }
+        });
+
         Ok(this)
     }
 
@@ -71,10 +83,10 @@ impl Actor for ClientApprovalController {
         _: ActorId,
         _: ActorStopReason,
     ) -> Result<ControlFlow<ActorStopReason>, Self::Error> {
-        // A linked UA died before responding — counts as a non-approval.
+        // 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 UA didn't approve: deny.
+            // At least one operator didn't approve: deny.
             self.send_reply(Ok(false));
             return Ok(ControlFlow::Break(ActorStopReason::Normal));
         }
@@ -85,7 +97,7 @@ impl Actor for ClientApprovalController {
 #[messages]
 impl ClientApprovalController {
     #[message(ctx)]
-    pub async fn client_approval_answer(&mut self, approved: bool, ctx: &mut Context<Self, ()>) {
+    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));
@@ -97,9 +109,19 @@ impl ClientApprovalController {
         self.pending = self.pending.saturating_sub(1);
 
         if self.pending == 0 {
-            // Every connected UA approved.
+            // Every connected operator approved.
             self.send_reply(Ok(true));
             ctx.stop();
         }
     }
+
+    /// Fired after `APPROVAL_TIMEOUT` elapses. Any operator that hasn't responded
+    /// by then is treated as a denial to prevent zombie sessions from blocking the flow.
+    #[message(ctx)]
+    pub fn on_approval_timeout(&mut self, ctx: &mut Context<Self, ()>) {
+        if self.pending > 0 {
+            self.send_reply(Ok(false));
+            ctx.stop();
+        }
+    }
 }

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

@@ -1,4 +1,10 @@
-use std::{collections::HashMap, ops::ControlFlow};
+use crate::{
+    actors::{
+        flow_coordinator::client_connect_approval::ClientApprovalController,
+        operator_registry::{GetConnected, OperatorRegistry},
+    },
+    peers::client::{ClientProfile, session::ClientSession},
+};
 
 use kameo::{
     Actor,
@@ -7,20 +13,26 @@ use kameo::{
     prelude::{ActorStopReason, Context, WeakActorRef},
     reply::DelegatedReply,
 };
+use std::{collections::HashMap, ops::ControlFlow};
 use tracing::info;
 
-use crate::actors::{
-    client::{ClientProfile, session::ClientSession},
-    flow_coordinator::client_connect_approval::ClientApprovalController,
-    user_agent::session::UserAgentSession,
-};
-
 pub mod client_connect_approval;
 
-#[derive(Default)]
 pub struct FlowCoordinator {
-    pub user_agents: HashMap<ActorId, ActorRef<UserAgentSession>>,
     pub clients: HashMap<ActorId, ActorRef<ClientSession>>,
+    /// Maps DB `client_id` → `ActorId` for fast connected-client lookup.
+    client_ids: HashMap<i32, ActorId>,
+    operator_registry: ActorRef<OperatorRegistry>,
+}
+
+impl FlowCoordinator {
+    pub fn new(operator_registry: ActorRef<OperatorRegistry>) -> Self {
+        Self {
+            clients: HashMap::default(),
+            client_ids: HashMap::default(),
+            operator_registry,
+        }
+    }
 }
 
 impl Actor for FlowCoordinator {
@@ -38,13 +50,8 @@ impl Actor for FlowCoordinator {
         id: ActorId,
         _: ActorStopReason,
     ) -> Result<ControlFlow<ActorStopReason>, Self::Error> {
-        if self.user_agents.remove(&id).is_some() {
+        if self.clients.remove(&id).is_some() {
-            info!(
+            self.client_ids.retain(|_, actor_id| *actor_id != id);
-                ?id,
-                actor = "FlowCoordinator",
-                event = "useragent.disconnected"
-            );
-        } else if self.clients.remove(&id).is_some() {
             info!(
                 ?id,
                 actor = "FlowCoordinator",
@@ -63,34 +70,37 @@ impl Actor for FlowCoordinator {
 
 #[derive(Debug, thiserror::Error, Clone, PartialEq, Eq, Hash)]
 pub enum ApprovalError {
-    #[error("No user agents connected")]
+    #[error("No operators connected")]
-    NoUserAgentsConnected,
+    NoOperatorsConnected,
 }
 
 #[messages]
 impl FlowCoordinator {
-    #[message(ctx)]
-    pub async fn register_user_agent(
-        &mut self,
-        actor: ActorRef<UserAgentSession>,
-        ctx: &mut Context<Self, ()>,
-    ) {
-        info!(id = %actor.id(), actor = "FlowCoordinator", 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,
+        client_id: i32,
         actor: ActorRef<ClientSession>,
         ctx: &mut Context<Self, ()>,
     ) {
-        info!(id = %actor.id(), actor = "FlowCoordinator", event = "client.connected");
+        info!(id = %actor.id(), client_id, actor = "FlowCoordinator", event = "client.connected");
         ctx.actor_ref().link(&actor).await;
+        self.client_ids.insert(client_id, actor.id());
         self.clients.insert(actor.id(), actor);
     }
 
+    #[message]
+    pub fn is_client_connected(&self, client_id: i32) -> bool {
+        self.client_ids.contains_key(&client_id)
+    }
+
+    /// Returns the DB `client_ids` of all currently connected SDK clients.
+    /// Used by operator sessions on startup to seed their approved-client set.
+    #[message]
+    pub fn get_connected_client_ids(&self) -> Vec<i32> {
+        self.client_ids.keys().copied().collect()
+    }
+
     #[message(ctx)]
     pub async fn request_client_approval(
         &mut self,
@@ -101,15 +111,19 @@ impl FlowCoordinator {
             unreachable!("Expected `request_client_approval` to have callback channel");
         };
 
-        let refs: Vec<_> = self.user_agents.values().cloned().collect();
+        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::NoUserAgentsConnected));
+            reply_sender.send(Err(ApprovalError::NoOperatorsConnected));
             return reply;
         }
 
         ClientApprovalController::spawn(client_connect_approval::Args {
             client,
-            user_agents: refs,
+            operators: refs,
             reply: reply_sender,
         });
 

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

@@ -1,243 +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 rand::{
-    Rng as _, SeedableRng,
-    rngs::{StdRng, SysRng},
-};
-
-use crate::safe_cell::{SafeCell, SafeCellHandle as _};
-
-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 SafeCell<Key>);
-impl From<SafeCell<Key>> for KeyCell {
-    fn from(value: SafeCell<Key>) -> Self {
-        Self(value)
-    }
-}
-impl TryFrom<SafeCell<Vec<u8>>> for KeyCell {
-    type Error = ();
-
-    fn try_from(mut value: SafeCell<Vec<u8>>) -> Result<Self, Self::Error> {
-        let value = value.read();
-        if value.len() != size_of::<Key>() {
-            return Err(());
-        }
-        let cell = SafeCell::new_inline(|cell_write: &mut Key| {
-            cell_write.copy_from_slice(&value);
-        });
-        Ok(Self(cell))
-    }
-}
-
-impl KeyCell {
-    pub fn new_secure_random() -> Self {
-        let key = SafeCell::new_inline(|key_buffer: &mut Key| {
-            #[allow(
-                clippy::unwrap_used,
-                reason = "Rng failure is unrecoverable and should panic"
-            )]
-            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();
-        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 SafeCell<Vec<u8>>,
-    ) -> Result<(), Error> {
-        let key_reader = self.0.read();
-        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();
-        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();
-        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();
-    #[allow(
-        clippy::unwrap_used,
-        reason = "Rng failure is unrecoverable and should panic"
-    )]
-    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: SafeCell<Vec<u8>>, salt: &Salt) -> KeyCell {
-    #[allow(clippy::unwrap_used)]
-    let params = argon2::Params::new(262_144, 3, 4, None).unwrap();
-    let hasher = Argon2::new(Algorithm::Argon2id, argon2::Version::V0x13, params);
-    let mut key = SafeCell::new(Key::default());
-    password.read_inline(|password_source| {
-        let mut key_buffer = key.write();
-        let key_buffer: &mut [u8] = key_buffer.as_mut();
-
-        #[allow(
-            clippy::unwrap_used,
-            reason = "Better fail completely than return a weak key"
-        )]
-        hasher
-            .hash_password_into(password_source.deref(), salt, key_buffer)
-            .unwrap();
-    });
-
-    key.into()
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::safe_cell::SafeCell;
-
-    #[test]
-    pub fn derive_seal_key_deterministic() {
-        static PASSWORD: &[u8] = b"password";
-        let password = SafeCell::new(PASSWORD.to_vec());
-        let password2 = SafeCell::new(PASSWORD.to_vec());
-        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();
-        let key2_reader = key2.0.read();
-
-        assert_eq!(key1_reader.deref(), key2_reader.deref());
-    }
-
-    #[test]
-    pub fn successful_derive() {
-        static PASSWORD: &[u8] = b"password";
-        let password = SafeCell::new(PASSWORD.to_vec());
-        let salt = generate_salt();
-
-        let mut key = derive_seal_key(password, &salt);
-        let key_reader = key.0.read();
-        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 = SafeCell::new(PASSWORD.to_vec());
-        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 = SafeCell::new(buffer);
-
-        key.decrypt_in_place(&nonce, associated_data, &mut buffer)
-            .unwrap();
-
-        let buffer = buffer.read();
-        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

@@ -1,403 +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 strum::{EnumDiscriminants, IntoDiscriminant};
-use tracing::{error, info};
-
-use crate::safe_cell::SafeCell;
-use crate::{
-    db::{
-        self,
-        models::{self, RootKeyHistory},
-        schema::{self},
-    },
-    safe_cell::SafeCellHandle as _,
-};
-use encryption::v1::{self, KeyCell, Nonce};
-
-pub mod encryption;
-
-#[derive(Default, EnumDiscriminants)]
-#[strum_discriminants(derive(Reply), vis(pub), name(KeyHolderState))]
-enum State {
-    #[default]
-    Unbootstrapped,
-    Sealed {
-        root_key_history_id: i32,
-    },
-    Unsealed {
-        root_key_history_id: i32,
-        root_key: KeyCell,
-    },
-}
-
-#[derive(Debug, thiserror::Error)]
-pub enum Error {
-    #[error("Keyholder is already bootstrapped")]
-    AlreadyBootstrapped,
-    #[error("Keyholder is not bootstrapped")]
-    NotBootstrapped,
-    #[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,
-}
-
-/// 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: SafeCell<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> = root_key.0.read_inline(|reader| {
-            let root_key_reader = 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: SafeCell<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(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 = SafeCell::new(current_key.ciphertext.clone());
-
-        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<SafeCell<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 = 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 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();
-        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) -> KeyHolderState {
-        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 crate::{
-        db::{self},
-        safe_cell::SafeCell,
-    };
-
-    use super::*;
-
-    async fn bootstrapped_actor(db: &db::DatabasePool) -> KeyHolder {
-        let mut actor = KeyHolder::new(db.clone()).await.unwrap();
-        let seal_key = SafeCell::new(b"test-seal-key".to_vec());
-        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(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"
-        );
-    }
-}

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

@@ -1,47 +1,72 @@
-use kameo::actor::{ActorRef, Spawn};
-use thiserror::Error;
-
 use crate::{
     actors::{
         bootstrap::Bootstrapper, evm::EvmActor, flow_coordinator::FlowCoordinator,
-        keyholder::KeyHolder,
+        operator_registry::OperatorRegistry, vault::Vault, vault_coordinator::VaultCoordinator,
+    },
+    db::{
+        self,
+        custody::{CustodyStore, DieselCustodyStore},
     },
-    db,
 };
 
+use std::sync::Arc;
+
+use kameo::actor::{ActorRef, Spawn};
+use kameo_actors::{DeliveryStrategy, message_bus::MessageBus};
+use thiserror::Error;
+
 pub mod bootstrap;
-pub mod client;
+pub mod evm;
-mod evm;
 pub mod flow_coordinator;
-pub mod keyholder;
+pub mod operator_registry;
-pub mod user_agent;
+pub mod vault;
+pub mod vault_coordinator;
 
 #[derive(Error, Debug)]
 pub enum SpawnError {
     #[error("Failed to spawn Bootstrapper actor")]
     Bootstrapper(#[from] bootstrap::Error),
-
+    #[error("Failed to spawn Vault actor")]
-    #[error("Failed to spawn KeyHolder actor")]
+    Vault(#[from] vault::Error),
-    KeyHolder(#[from] keyholder::Error),
+    #[error("Failed to spawn VaultCoordinator actor")]
+    VaultCoordinator(#[from] vault_coordinator::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 vault_coordinator: ActorRef<VaultCoordinator>,
     pub bootstrapper: ActorRef<Bootstrapper>,
     pub flow_coordinator: ActorRef<FlowCoordinator>,
+    pub operator_registry: ActorRef<OperatorRegistry>,
     pub evm: ActorRef<EvmActor>,
+    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 events = Self::spawn_message_bus();
+        let custody: Arc<dyn CustodyStore> = Arc::new(DieselCustodyStore);
+        let vault =
+            Vault::spawn(Vault::new(db.clone(), events.clone(), Arc::clone(&custody)).await?);
+        let bootstrapper = Bootstrapper::spawn(Bootstrapper::new(&db, events.clone()).await?);
+        let vault_coordinator =
+            VaultCoordinator::spawn(VaultCoordinator::new(db.clone(), vault.clone(), custody));
+        let operator_registry = OperatorRegistry::spawn(OperatorRegistry::default());
         Ok(Self {
-            bootstrapper: Bootstrapper::spawn(Bootstrapper::new(&db).await?),
+            bootstrapper,
-            evm: EvmActor::spawn(EvmActor::new(key_holder.clone(), db)),
+            evm: EvmActor::spawn(EvmActor::new(vault.clone(), db.clone())),
-            key_holder,
+            vault,
-            flow_coordinator: FlowCoordinator::spawn(FlowCoordinator::default()),
+            vault_coordinator,
+            flow_coordinator: FlowCoordinator::spawn(FlowCoordinator::new(
+                operator_registry.clone(),
+            )),
+            operator_registry,
+            events,
         })
     }
 }

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;
+
+    fn on_start(args: Self::Args, _: ActorRef<Self>) -> impl Future<Output = Result<Self, Self::Error>> {
+        std::future::ready(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/user_agent/auth/state.rs

@@ -1,225 +0,0 @@
-use arbiter_proto::transport::Bi;
-use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl, update};
-use diesel_async::RunQueryDsl;
-use tracing::error;
-
-use super::Error;
-use crate::{
-    actors::{
-        bootstrap::ConsumeToken,
-        user_agent::{AuthPublicKey, UserAgentConnection, auth::Outbound},
-    },
-    db::schema,
-};
-
-pub struct ChallengeRequest {
-    pub pubkey: AuthPublicKey,
-}
-
-pub struct BootstrapAuthRequest {
-    pub pubkey: AuthPublicKey,
-    pub token: String,
-}
-
-pub struct ChallengeContext {
-    pub challenge_nonce: i32,
-    pub key: AuthPublicKey,
-}
-
-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 = AuthOk(AuthPublicKey),
-        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) / async verify_solution = AuthOk(AuthPublicKey),
-    }
-);
-
-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::internal("Database unavailable")
-    })?;
-    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::internal("Database operation failed")
-        })?
-        .ok_or_else(|| {
-            error!(?pubkey_bytes, "Public key not found in database");
-            Error::UnregisteredPublicKey
-        })
-}
-
-async fn register_key(db: &crate::db::DatabasePool, pubkey: &AuthPublicKey) -> Result<(), Error> {
-    let pubkey_bytes = pubkey.to_stored_bytes();
-    let key_type = pubkey.key_type();
-    let mut conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::internal("Database unavailable")
-    })?;
-
-    diesel::insert_into(schema::useragent_client::table)
-        .values((
-            schema::useragent_client::public_key.eq(pubkey_bytes),
-            schema::useragent_client::nonce.eq(1),
-            schema::useragent_client::key_type.eq(key_type),
-        ))
-        .execute(&mut conn)
-        .await
-        .map_err(|e| {
-            error!(error = ?e, "Database error");
-            Error::internal("Database operation failed")
-        })?;
-
-    Ok(())
-}
-
-pub struct AuthContext<'a, T> {
-    pub(super) conn: &'a mut UserAgentConnection,
-    pub(super) transport: T,
-}
-
-impl<'a, T> AuthContext<'a, T> {
-    pub fn new(conn: &'a mut UserAgentConnection, transport: T) -> Self {
-        Self { conn, transport }
-    }
-}
-
-impl<T> AuthStateMachineContext for AuthContext<'_, T>
-where
-    T: Bi<super::Inbound, Result<super::Outbound, Error>> + Send,
-{
-    type Error = Error;
-
-    async fn prepare_challenge(
-        &mut self,
-        ChallengeRequest { pubkey }: ChallengeRequest,
-    ) -> Result<ChallengeContext, Self::Error> {
-        let stored_bytes = pubkey.to_stored_bytes();
-        let nonce = create_nonce(&self.conn.db, &stored_bytes).await?;
-
-        self.transport
-            .send(Ok(Outbound::AuthChallenge { nonce }))
-            .await
-            .map_err(|e| {
-                error!(?e, "Failed to send auth challenge");
-                Error::Transport
-            })?;
-
-        Ok(ChallengeContext {
-            challenge_nonce: nonce,
-            key: pubkey,
-        })
-    }
-
-    #[allow(missing_docs)]
-    #[allow(clippy::result_unit_err)]
-    async fn verify_bootstrap_token(
-        &mut self,
-        BootstrapAuthRequest { pubkey, token }: BootstrapAuthRequest,
-    ) -> Result<AuthPublicKey, Self::Error> {
-        let token_ok: bool = self
-            .conn
-            .actors
-            .bootstrapper
-            .ask(ConsumeToken {
-                token: token.clone(),
-            })
-            .await
-            .map_err(|e| {
-                error!(?e, "Failed to consume bootstrap token");
-                Error::internal("Failed to consume bootstrap token")
-            })?;
-
-        if !token_ok {
-            error!("Invalid bootstrap token provided");
-            return Err(Error::InvalidBootstrapToken);
-        }
-
-        register_key(&self.conn.db, &pubkey).await?;
-
-        self.transport
-            .send(Ok(Outbound::AuthSuccess))
-            .await
-            .map_err(|_| Error::Transport)?;
-
-        Ok(pubkey)
-    }
-
-    #[allow(missing_docs)]
-    #[allow(clippy::unused_unit)]
-    async fn verify_solution(
-        &mut self,
-        ChallengeContext {
-            challenge_nonce,
-            key,
-        }: &ChallengeContext,
-        ChallengeSolution { solution }: ChallengeSolution,
-    ) -> Result<AuthPublicKey, Self::Error> {
-        let formatted = arbiter_proto::format_challenge(*challenge_nonce, &key.to_stored_bytes());
-
-        let valid = match key {
-            AuthPublicKey::Ed25519(vk) => {
-                let sig = solution.as_slice().try_into().map_err(|_| {
-                    error!(?solution, "Invalid Ed25519 signature length");
-                    Error::InvalidChallengeSolution
-                })?;
-                vk.verify_strict(&formatted, &sig).is_ok()
-            }
-            AuthPublicKey::EcdsaSecp256k1(vk) => {
-                use k256::ecdsa::signature::Verifier as _;
-                let sig = k256::ecdsa::Signature::try_from(solution.as_slice()).map_err(|_| {
-                    error!(?solution, "Invalid ECDSA signature bytes");
-                    Error::InvalidChallengeSolution
-                })?;
-                vk.verify(&formatted, &sig).is_ok()
-            }
-            AuthPublicKey::Rsa(pk) => {
-                use rsa::signature::Verifier as _;
-                let verifying_key = rsa::pss::VerifyingKey::<sha2::Sha256>::new(pk.clone());
-                let sig = rsa::pss::Signature::try_from(solution.as_slice()).map_err(|_| {
-                    error!(?solution, "Invalid RSA signature bytes");
-                    Error::InvalidChallengeSolution
-                })?;
-                verifying_key.verify(&formatted, &sig).is_ok()
-            }
-        };
-
-        if !valid {
-            error!("Invalid challenge solution signature");
-            return Err(Error::InvalidChallengeSolution);
-        }
-
-        self.transport
-            .send(Ok(Outbound::AuthSuccess))
-            .await
-            .map_err(|_| Error::Transport)?;
-
-        Ok(key.clone())
-    }
-}

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

@@ -1,94 +0,0 @@
-use crate::{
-    actors::{GlobalActors, client::ClientProfile},
-    db::{self, models::KeyType},
-};
-
-/// Abstraction over Ed25519 / ECDSA-secp256k1 / RSA public keys used during the auth handshake.
-#[derive(Clone, Debug)]
-pub enum AuthPublicKey {
-    Ed25519(ed25519_dalek::VerifyingKey),
-    /// Compressed SEC1 public key; signature bytes are raw 64-byte (r||s).
-    EcdsaSecp256k1(k256::ecdsa::VerifyingKey),
-    /// RSA-2048+ public key (Windows Hello / KeyCredentialManager); signature bytes are PSS+SHA-256.
-    Rsa(rsa::RsaPublicKey),
-}
-
-impl AuthPublicKey {
-    /// Canonical bytes stored in DB and echoed back in the challenge.
-    /// Ed25519: raw 32 bytes. ECDSA: SEC1 compressed 33 bytes. RSA: DER-encoded SPKI.
-    pub fn to_stored_bytes(&self) -> Vec<u8> {
-        match self {
-            AuthPublicKey::Ed25519(k) => k.to_bytes().to_vec(),
-            // SEC1 compressed (33 bytes) is the natural compact format for secp256k1
-            AuthPublicKey::EcdsaSecp256k1(k) => k.to_encoded_point(true).as_bytes().to_vec(),
-            AuthPublicKey::Rsa(k) => {
-                use rsa::pkcs8::EncodePublicKey as _;
-                #[allow(clippy::expect_used)]
-                k.to_public_key_der()
-                    .expect("rsa SPKI encoding is infallible")
-                    .to_vec()
-            }
-        }
-    }
-
-    pub fn key_type(&self) -> KeyType {
-        match self {
-            AuthPublicKey::Ed25519(_) => KeyType::Ed25519,
-            AuthPublicKey::EcdsaSecp256k1(_) => KeyType::EcdsaSecp256k1,
-            AuthPublicKey::Rsa(_) => KeyType::Rsa,
-        }
-    }
-}
-
-impl TryFrom<(KeyType, Vec<u8>)> for AuthPublicKey {
-    type Error = &'static str;
-
-    fn try_from(value: (KeyType, Vec<u8>)) -> Result<Self, Self::Error> {
-        let (key_type, bytes) = value;
-        match key_type {
-            KeyType::Ed25519 => {
-                let bytes: [u8; 32] = bytes.try_into().map_err(|_| "invalid Ed25519 key length")?;
-                let key = ed25519_dalek::VerifyingKey::from_bytes(&bytes)
-                    .map_err(|_e| "invalid Ed25519 key")?;
-                Ok(AuthPublicKey::Ed25519(key))
-            }
-            KeyType::EcdsaSecp256k1 => {
-                let point =
-                    k256::EncodedPoint::from_bytes(&bytes).map_err(|_e| "invalid ECDSA key")?;
-                let key = k256::ecdsa::VerifyingKey::from_encoded_point(&point)
-                    .map_err(|_e| "invalid ECDSA key")?;
-                Ok(AuthPublicKey::EcdsaSecp256k1(key))
-            }
-            KeyType::Rsa => {
-                use rsa::pkcs8::DecodePublicKey as _;
-                let key = rsa::RsaPublicKey::from_public_key_der(&bytes)
-                    .map_err(|_e| "invalid RSA key")?;
-                Ok(AuthPublicKey::Rsa(key))
-            }
-        }
-    }
-}
-
-// Messages, sent by user agent to connection client without having a request
-#[derive(Debug)]
-pub enum OutOfBand {
-    ClientConnectionRequest { profile: ClientProfile },
-    ClientConnectionCancel { pubkey: ed25519_dalek::VerifyingKey },
-}
-
-pub struct UserAgentConnection {
-    pub(crate) db: db::DatabasePool,
-    pub(crate) actors: GlobalActors,
-}
-
-impl UserAgentConnection {
-    pub fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
-        Self { db, actors }
-    }
-}
-
-pub mod auth;
-pub mod session;
-
-pub use auth::authenticate;
-pub use session::UserAgentSession;

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

@@ -1,510 +0,0 @@
-use std::sync::Mutex;
-
-use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
-use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
-use diesel::{ExpressionMethods as _, QueryDsl as _, SelectableHelper};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::error::SendError;
-use kameo::messages;
-use kameo::prelude::Context;
-use tracing::{error, info};
-use x25519_dalek::{EphemeralSecret, PublicKey};
-
-use crate::actors::flow_coordinator::client_connect_approval::ClientApprovalAnswer;
-use crate::actors::keyholder::KeyHolderState;
-use crate::actors::user_agent::session::Error;
-use crate::db::models::{
-    EvmWalletAccess, NewEvmWalletAccess, ProgramClient, ProgramClientMetadata,
-};
-use crate::evm::policies::{Grant, SpecificGrant};
-use crate::safe_cell::SafeCell;
-use crate::{
-    actors::{
-        evm::{
-            ClientSignTransaction, Generate, ListWallets, SignTransactionError as EvmSignError,
-            UseragentCreateGrant, UseragentDeleteGrant, UseragentListGrants,
-        },
-        keyholder::{self, Bootstrap, TryUnseal},
-        user_agent::session::{
-            UserAgentSession,
-            state::{UnsealContext, UserAgentEvents, UserAgentStates},
-        },
-    },
-    safe_cell::SafeCellHandle as _,
-};
-
-impl UserAgentSession {
-    fn take_unseal_secret(&mut self) -> Result<(EphemeralSecret, PublicKey), Error> {
-        let UserAgentStates::WaitingForUnsealKey(unseal_context) = self.state.state() else {
-            error!("Received encrypted key in invalid state");
-            return Err(Error::internal("Invalid state for unseal encrypted key"));
-        };
-
-        let ephemeral_secret = {
-            #[allow(
-                clippy::unwrap_used,
-                reason = "Mutex poison is unrecoverable and should panic"
-            )]
-            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");
-                    return Err(Error::internal("Ephemeral secret already taken"));
-                }
-            }
-        };
-
-        Ok((ephemeral_secret, unseal_context.client_public_key))
-    }
-
-    fn decrypt_client_key_material(
-        ephemeral_secret: EphemeralSecret,
-        client_public_key: PublicKey,
-        nonce: &[u8],
-        ciphertext: &[u8],
-        associated_data: &[u8],
-    ) -> Result<SafeCell<Vec<u8>>, ()> {
-        let nonce = XNonce::from_slice(nonce);
-
-        let shared_secret = ephemeral_secret.diffie_hellman(&client_public_key);
-        let cipher = XChaCha20Poly1305::new(shared_secret.as_bytes().into());
-
-        let mut key_buffer = SafeCell::new(ciphertext.to_vec());
-
-        let decryption_result = key_buffer.write_inline(|write_handle| {
-            cipher.decrypt_in_place(nonce, associated_data, write_handle)
-        });
-
-        match decryption_result {
-            Ok(_) => Ok(key_buffer),
-            Err(err) => {
-                error!(?err, "Failed to decrypt encrypted key material");
-                Err(())
-            }
-        }
-    }
-}
-
-pub struct UnsealStartResponse {
-    pub server_pubkey: PublicKey,
-}
-
-#[derive(Debug, Error)]
-pub enum UnsealError {
-    #[error("Invalid key provided for unsealing")]
-    InvalidKey,
-    #[error("Internal error during unsealing process")]
-    General(#[from] super::Error),
-}
-
-#[derive(Debug, Error)]
-pub enum BootstrapError {
-    #[error("Invalid key provided for bootstrapping")]
-    InvalidKey,
-    #[error("Vault is already bootstrapped")]
-    AlreadyBootstrapped,
-
-    #[error("Internal error during bootstrapping process")]
-    General(#[from] super::Error),
-}
-
-#[derive(Debug, Error)]
-pub enum SignTransactionError {
-    #[error("Policy evaluation failed")]
-    Vet(#[from] crate::evm::VetError),
-
-    #[error("Internal signing error")]
-    Internal,
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub async fn handle_unseal_request(
-        &mut self,
-        client_pubkey: x25519_dalek::PublicKey,
-    ) -> Result<UnsealStartResponse, Error> {
-        let secret = EphemeralSecret::random();
-        let public_key = PublicKey::from(&secret);
-
-        self.transition(UserAgentEvents::UnsealRequest(UnsealContext {
-            secret: Mutex::new(Some(secret)),
-            client_public_key: client_pubkey,
-        }))?;
-
-        Ok(UnsealStartResponse {
-            server_pubkey: public_key,
-        })
-    }
-
-    #[message]
-    pub async fn handle_unseal_encrypted_key(
-        &mut self,
-        nonce: Vec<u8>,
-        ciphertext: Vec<u8>,
-        associated_data: Vec<u8>,
-    ) -> Result<(), UnsealError> {
-        let (ephemeral_secret, client_public_key) = match self.take_unseal_secret() {
-            Ok(values) => values,
-            Err(Error::State) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(UnsealError::InvalidKey);
-            }
-            Err(_err) => {
-                return Err(Error::internal("Failed to take unseal secret").into());
-            }
-        };
-
-        let seal_key_buffer = match Self::decrypt_client_key_material(
-            ephemeral_secret,
-            client_public_key,
-            &nonce,
-            &ciphertext,
-            &associated_data,
-        ) {
-            Ok(buffer) => buffer,
-            Err(()) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(UnsealError::InvalidKey);
-            }
-        };
-
-        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(())
-            }
-            Err(SendError::HandlerError(keyholder::Error::InvalidKey)) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(UnsealError::InvalidKey)
-            }
-            Err(SendError::HandlerError(err)) => {
-                error!(?err, "Keyholder failed to unseal key");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(UnsealError::InvalidKey)
-            }
-            Err(err) => {
-                error!(?err, "Failed to send unseal request to keyholder");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(Error::internal("Vault actor error").into())
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_bootstrap_encrypted_key(
-        &mut self,
-        nonce: Vec<u8>,
-        ciphertext: Vec<u8>,
-        associated_data: Vec<u8>,
-    ) -> Result<(), BootstrapError> {
-        let (ephemeral_secret, client_public_key) = match self.take_unseal_secret() {
-            Ok(values) => values,
-            Err(Error::State) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(BootstrapError::InvalidKey);
-            }
-            Err(err) => return Err(err.into()),
-        };
-
-        let seal_key_buffer = match Self::decrypt_client_key_material(
-            ephemeral_secret,
-            client_public_key,
-            &nonce,
-            &ciphertext,
-            &associated_data,
-        ) {
-            Ok(buffer) => buffer,
-            Err(()) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(BootstrapError::InvalidKey);
-            }
-        };
-
-        match self
-            .props
-            .actors
-            .key_holder
-            .ask(Bootstrap {
-                seal_key_raw: seal_key_buffer,
-            })
-            .await
-        {
-            Ok(_) => {
-                info!("Successfully bootstrapped vault with client-provided key");
-                self.transition(UserAgentEvents::ReceivedValidKey)?;
-                Ok(())
-            }
-            Err(SendError::HandlerError(keyholder::Error::AlreadyBootstrapped)) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::AlreadyBootstrapped)
-            }
-            Err(SendError::HandlerError(err)) => {
-                error!(?err, "Keyholder failed to bootstrap vault");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::InvalidKey)
-            }
-            Err(err) => {
-                error!(?err, "Failed to send bootstrap request to keyholder");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::General(Error::internal(
-                    "Vault actor error",
-                )))
-            }
-        }
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<KeyHolderState, Error> {
-        use crate::actors::keyholder::GetState;
-
-        let vault_state = match self.props.actors.key_holder.ask(GetState {}).await {
-            Ok(state) => state,
-            Err(err) => {
-                error!(?err, actor = "useragent", "keyholder.query.failed");
-                return Err(Error::internal("Vault is in broken state"));
-            }
-        };
-
-        Ok(vault_state)
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub(crate) async fn handle_evm_wallet_create(&mut self) -> Result<(i32, Address), Error> {
-        match self.props.actors.evm.ask(Generate {}).await {
-            Ok(address) => Ok(address),
-            Err(SendError::HandlerError(err)) => Err(Error::internal(format!(
-                "EVM wallet generation failed: {err}"
-            ))),
-            Err(err) => {
-                error!(?err, "EVM actor unreachable during wallet create");
-                Err(Error::internal("EVM actor unreachable"))
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_evm_wallet_list(&mut self) -> Result<Vec<(i32, Address)>, Error> {
-        match self.props.actors.evm.ask(ListWallets {}).await {
-            Ok(wallets) => Ok(wallets),
-            Err(err) => {
-                error!(?err, "EVM wallet list failed");
-                Err(Error::internal("Failed to list EVM wallets"))
-            }
-        }
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub(crate) async fn handle_grant_list(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
-        match self.props.actors.evm.ask(UseragentListGrants {}).await {
-            Ok(grants) => Ok(grants),
-            Err(err) => {
-                error!(?err, "EVM grant list failed");
-                Err(Error::internal("Failed to list EVM grants"))
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_grant_create(
-        &mut self,
-        basic: crate::evm::policies::SharedGrantSettings,
-        grant: crate::evm::policies::SpecificGrant,
-    ) -> Result<i32, Error> {
-        match self
-            .props
-            .actors
-            .evm
-            .ask(UseragentCreateGrant { basic, grant })
-            .await
-        {
-            Ok(grant_id) => Ok(grant_id),
-            Err(err) => {
-                error!(?err, "EVM grant create failed");
-                Err(Error::internal("Failed to create EVM grant"))
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_grant_delete(&mut self, grant_id: i32) -> Result<(), Error> {
-        match self
-            .props
-            .actors
-            .evm
-            .ask(UseragentDeleteGrant { grant_id })
-            .await
-        {
-            Ok(()) => Ok(()),
-            Err(err) => {
-                error!(?err, "EVM grant delete failed");
-                Err(Error::internal("Failed to delete EVM grant"))
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_sign_transaction(
-        &mut self,
-        client_id: i32,
-        wallet_address: Address,
-        transaction: TxEip1559,
-    ) -> Result<Signature, SignTransactionError> {
-        match self
-            .props
-            .actors
-            .evm
-            .ask(ClientSignTransaction {
-                client_id,
-                wallet_address,
-                transaction,
-            })
-            .await
-        {
-            Ok(signature) => Ok(signature),
-            Err(SendError::HandlerError(EvmSignError::Vet(vet_error))) => {
-                Err(SignTransactionError::Vet(vet_error))
-            }
-            Err(err) => {
-                error!(?err, "EVM sign transaction failed in user-agent session");
-                Err(SignTransactionError::Internal)
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_grant_evm_wallet_access(
-        &mut self,
-        entries: Vec<NewEvmWalletAccess>,
-    ) -> Result<(), Error> {
-        let mut conn = self.props.db.get().await?;
-        conn.transaction(|conn| {
-            Box::pin(async move {
-                use crate::db::schema::evm_wallet_access;
-
-                for entry in entries {
-                    diesel::insert_into(evm_wallet_access::table)
-                        .values(&entry)
-                        .on_conflict_do_nothing()
-                        .execute(conn)
-                        .await?;
-                }
-
-                Result::<_, Error>::Ok(())
-            })
-        })
-        .await?;
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_revoke_evm_wallet_access(
-        &mut self,
-        entries: Vec<i32>,
-    ) -> Result<(), Error> {
-        let mut conn = self.props.db.get().await?;
-        conn.transaction(|conn| {
-            Box::pin(async move {
-                use crate::db::schema::evm_wallet_access;
-                for entry in entries {
-                    diesel::delete(evm_wallet_access::table)
-                        .filter(evm_wallet_access::wallet_id.eq(entry))
-                        .execute(conn)
-                        .await?;
-                }
-
-                Result::<_, Error>::Ok(())
-            })
-        })
-        .await?;
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_list_wallet_access(
-        &mut self,
-    ) -> Result<Vec<EvmWalletAccess>, Error> {
-        let mut conn = self.props.db.get().await?;
-        use crate::db::schema::evm_wallet_access;
-        let access_entries = evm_wallet_access::table
-            .select(EvmWalletAccess::as_select())
-            .load::<_>(&mut conn)
-            .await?;
-        Ok(access_entries)
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message(ctx)]
-    pub(crate) async fn handle_new_client_approve(
-        &mut self,
-        approved: bool,
-        pubkey: ed25519_dalek::VerifyingKey,
-        ctx: &mut Context<Self, Result<(), Error>>,
-    ) -> Result<(), Error> {
-        let pending_approval = match self.pending_client_approvals.remove(&pubkey) {
-            Some(approval) => approval,
-            None => {
-                error!("Received client connection response for unknown client");
-                return Err(Error::internal("Unknown client in connection response"));
-            }
-        };
-
-        pending_approval
-            .controller
-            .tell(ClientApprovalAnswer { approved })
-            .await
-            .map_err(|err| {
-                error!(
-                    ?err,
-                    "Failed to send client approval response to controller"
-                );
-                Error::internal("Failed to send client approval response to controller")
-            })?;
-
-        ctx.actor_ref().unlink(&pending_approval.controller).await;
-
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_sdk_client_list(
-        &mut self,
-    ) -> Result<Vec<(ProgramClient, ProgramClientMetadata)>, Error> {
-        use crate::db::schema::{client_metadata, program_client};
-        let mut conn = self.props.db.get().await?;
-
-        let clients = program_client::table
-            .inner_join(client_metadata::table)
-            .select((
-                ProgramClient::as_select(),
-                ProgramClientMetadata::as_select(),
-            ))
-            .load::<(ProgramClient, ProgramClientMetadata)>(&mut conn)
-            .await?;
-
-        Ok(clients)
-    }
-}

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 +1,522 @@
+use crate::{
+    crypto::{
+        KeyCell,
+        encryption::v1::{self, Nonce},
+        integrity::v1::HmacSha256,
+    },
+    db::{
+        self,
+        custody::{CustodyRecord, CustodyStore},
+        models::{self, RootKeyHistory, RootKeyHistoryId},
+        schema::{self},
+    },
+};
+
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use std::sync::Arc;
+
+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};
+use kameo_actors::message_bus::{MessageBus, Publish};
+use strum::{EnumDiscriminants, IntoDiscriminant};
+use tracing::{error, info, warn};
+
+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("Vault locked: too many failed unseal attempts")]
+    LockedOut,
+
+    #[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("Custody storage error: {0}")]
+    Custody(#[from] db::custody::Error),
+
+    #[error("Broken database")]
+    BrokenDatabase,
+
+    #[error("Integrity key version mismatch: envelope uses key {envelope:?}, current key is {current:?}")]
+    KeyVersionMismatch { envelope: RootKeyHistoryId, current: RootKeyHistoryId },
+}
+
+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),
+}
+
+const MAX_UNSEAL_ATTEMPTS: u32 = 5;
+
+/// 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>,
+    custody: Arc<dyn CustodyStore>,
+    unseal_failures: u32,
+}
+
+#[messages]
+impl Vault {
+    pub async fn new(
+        db: db::DatabasePool,
+        events: ActorRef<MessageBus>,
+        custody: Arc<dyn CustodyStore>,
+    ) -> 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,
+            custody,
+            unseal_failures: 0,
+        })
+    }
+
+    // Exclusive transaction to avoid race condtions 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),
+        }
+    }
+
+    /// Create the root key and take the vault into the unsealed state.
+    #[message]
+    pub async fn bootstrap(
+        &mut self,
+        mut seal_key: KeyCell,
+        custody: Option<CustodyRecord>,
+    ) -> 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();
+
+        let root_key_ciphertext: Vec<u8> = root_key.0.read_inline(|reader| {
+            let root_key_reader = 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 custody_store = Arc::clone(&self.custody);
+        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: v1::generate_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?;
+
+                if let Some(record) = custody.as_ref() {
+                    custody_store.write_record(&mut *conn, record).await?;
+                }
+
+                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");
+        let _ = self.events.tell(Publish(events::Bootstrapped)).await;
+
+        Ok(())
+    }
+
+    #[message]
+    pub async fn try_unseal(&mut self, mut seal_key: KeyCell) -> Result<(), Error> {
+        if self.unseal_failures >= MAX_UNSEAL_ATTEMPTS {
+            return Err(Error::LockedOut);
+        }
+
+        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(RootKeyHistory::as_select())
+                .first(&mut conn)
+                .await?
+        };
+
+        let mut root_key = SafeCell::new(current_key.ciphertext.clone());
+
+        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
+            })?;
+
+        if seal_key
+            .decrypt_in_place(&nonce, v1::ROOT_KEY_TAG, &mut root_key)
+            .is_err()
+        {
+            self.unseal_failures += 1;
+            if self.unseal_failures >= MAX_UNSEAL_ATTEMPTS {
+                error!(
+                    attempts = self.unseal_failures,
+                    "Vault locked: maximum failed unseal attempts reached"
+                );
+            } else {
+                warn!(
+                    attempts = self.unseal_failures,
+                    remaining = MAX_UNSEAL_ATTEMPTS - self.unseal_failures,
+                    "Failed unseal attempt"
+                );
+            }
+            return Err(Error::InvalidKey);
+        }
+
+        self.unseal_failures = 0;
+        self.state = State::Unsealed(Unsealed {
+            root_key_history_id: current_key.id,
+            root_key: KeyCell::try_from(root_key).map_err(|err| {
+                error!(?err, "Broken database: invalid encryption key size");
+                Error::BrokenDatabase
+            })?,
+        });
+
+        info!("Vault unsealed successfully");
+        let _ = self.events.tell(Publish(events::Unsealed)).await;
+
+        Ok(())
+    }
+
+    /// Decrypts an AEAD entry. The `aad` must match the value used at encryption time;
+    /// a mismatch causes authentication failure, preventing cross-wallet key swaps.
+    #[message]
+    pub async fn decrypt(&mut self, aead_id: i32, aad: Vec<u8>) -> 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, &aad, &mut output)?;
+        Ok(output)
+    }
+
+    /// Creates a new `aead_encrypted` entry and returns its ID.
+    /// The `aad` is bound into the ciphertext and must be reproduced exactly at decryption time.
+    // 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>>, aad: 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, &aad, &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 Err(Error::KeyVersionMismatch {
+                envelope: key_version,
+                current: *root_key_history_id,
+            });
+        }
+
+        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())
+    }
+
+    #[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(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{actors::GlobalActors, db::custody::DieselCustodyStore};
+
+    use super::*;
+
+    async fn bootstrapped_actor(db: &db::DatabasePool) -> Vault {
+        let mut actor = Vault::new(
+            db.clone(),
+            GlobalActors::spawn_message_bus(),
+            Arc::new(DieselCustodyStore),
+        )
+        .await
+        .unwrap();
+        let seal_key = KeyCell::from([0u8; 32]);
+        actor.bootstrap(seal_key, None).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()), b"test-aad".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"
+        );
+    }
+}

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

@@ -0,0 +1,397 @@
+//! Coordinates the multi-operator ceremonies that create and open the vault.
+//!
+//! The coordinator collects one passphrase per committee member, then hands the
+//! assembled material to [`Vault`] in a single message. It owns no Diesel code:
+//! everything it reads or writes goes through [`CustodyStore`].
+
+use std::sync::Arc;
+
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use argon2::RECOMMENDED_SALT_LEN;
+use kameo::{Actor, actor::ActorRef, error::SendError, messages};
+use rand::rngs::SysRng;
+use rand_core::{Rng as _, UnwrapErr};
+
+use crate::{
+    actors::vault::{self, Bootstrap, TryUnseal, Vault},
+    crypto::{KeyCell, derive_key, encryption::v1::Nonce, shamir},
+    db::{
+        self,
+        custody::{CustodyRecord, CustodyStore, EncryptedShare},
+        models::OperatorId,
+    },
+};
+
+const SHARE_AAD: &[u8] = b"arbiter/shamir-share/v1";
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("An ordinary committee is already being coordinated")]
+    AlreadyBootstrapping,
+    #[error("An unseal is already being coordinated")]
+    AlreadyUnsealing,
+    #[error("Bootstrap is not in progress")]
+    NotBootstrapping,
+    #[error("The operator already contributed")]
+    DuplicateContribution,
+    #[error("The ordinary committee cannot be empty")]
+    EmptyCommittee,
+    #[error("Two-operator committees are unsupported")]
+    UnsupportedCommittee,
+    #[error(
+        "The ordinary committee cannot exceed {} members",
+        shamir::MAX_COMMITTEE_SIZE
+    )]
+    CommitteeTooLarge,
+    #[error("Invalid passphrase")]
+    InvalidPassphrase,
+    #[error("Broken database")]
+    BrokenDatabase,
+    #[error("Shamir error: {0}")]
+    Shamir(String),
+    #[error("Database connection error: {0}")]
+    DatabaseConnection(#[from] db::PoolError),
+    #[error("Custody storage error: {0}")]
+    Custody(#[from] db::custody::Error),
+    #[error("Encryption error")]
+    Encryption,
+    #[error("The vault is already bootstrapped")]
+    AlreadyBootstrapped,
+    #[error("Vault error")]
+    Vault,
+}
+
+/// Passphrases gathered so far, in contribution order.
+///
+/// A `Vec` rather than a map because [`SafeCell`] values are neither cloneable
+/// nor hashable, and a committee holds at most
+/// [`shamir::MAX_COMMITTEE_SIZE`] of them.
+#[derive(Default)]
+struct Contributions(Vec<(OperatorId, SafeCell<Vec<u8>>)>);
+
+impl Contributions {
+    fn contains(&self, operator_id: OperatorId) -> bool {
+        self.0.iter().any(|(id, _)| *id == operator_id)
+    }
+
+    fn put(&mut self, operator_id: OperatorId, passphrase: SafeCell<Vec<u8>>) {
+        match self.0.iter_mut().find(|(id, _)| *id == operator_id) {
+            Some(slot) => slot.1 = passphrase,
+            None => self.0.push((operator_id, passphrase)),
+        }
+    }
+
+    const fn len(&self) -> usize {
+        self.0.len()
+    }
+
+    fn operators(&self) -> Vec<OperatorId> {
+        self.0.iter().map(|(id, _)| *id).collect()
+    }
+}
+
+enum CoordinatorState {
+    Idle,
+    Bootstrapping {
+        /// The operator that declared the committee. Only they may re-declare
+        /// it, which is the way out of a ceremony the others never finish.
+        declarer: OperatorId,
+        declared_count: usize,
+        contributions: Contributions,
+        retryable: bool,
+    },
+    Unsealing {
+        threshold: usize,
+        contributions: Contributions,
+        retryable: bool,
+    },
+}
+
+#[derive(Actor)]
+pub struct VaultCoordinator {
+    db: db::DatabasePool,
+    vault: ActorRef<Vault>,
+    custody: Arc<dyn CustodyStore>,
+    state: CoordinatorState,
+}
+
+impl VaultCoordinator {
+    pub fn new(
+        db: db::DatabasePool,
+        vault: ActorRef<Vault>,
+        custody: Arc<dyn CustodyStore>,
+    ) -> Self {
+        Self {
+            db,
+            vault,
+            custody,
+            state: CoordinatorState::Idle,
+        }
+    }
+}
+
+/// Explain why a committee size was rejected.
+const fn committee_error(declared_count: usize) -> Error {
+    match declared_count {
+        0 => Error::EmptyCommittee,
+        2 => Error::UnsupportedCommittee,
+        _ => Error::CommitteeTooLarge,
+    }
+}
+
+fn encrypt_share(
+    passphrase: &mut SafeCell<Vec<u8>>,
+    share: &[u8],
+) -> Result<EncryptedShare, Error> {
+    let mut salt = [0u8; RECOMMENDED_SALT_LEN];
+    UnwrapErr(SysRng).fill_bytes(&mut salt);
+
+    let nonce = Nonce::default();
+    let ciphertext = derive_key(passphrase, &salt)
+        .encrypt(&nonce, SHARE_AAD, share)
+        .map_err(|_| Error::Encryption)?;
+
+    Ok(EncryptedShare {
+        ciphertext,
+        nonce: nonce.to_vec(),
+        salt: salt.to_vec(),
+    })
+}
+
+fn decrypt_share(
+    passphrase: &mut SafeCell<Vec<u8>>,
+    share: EncryptedShare,
+) -> Result<SafeCell<Vec<u8>>, Error> {
+    let nonce = Nonce::try_from(share.nonce.as_slice()).map_err(|()| Error::BrokenDatabase)?;
+
+    let mut buffer = SafeCell::new(share.ciphertext);
+    derive_key(passphrase, &share.salt)
+        .decrypt_in_place(&nonce, SHARE_AAD, &mut buffer)
+        .map_err(|_| Error::InvalidPassphrase)?;
+
+    Ok(buffer)
+}
+
+const fn bootstrap_error(error: &SendError<Bootstrap, vault::Error>) -> Error {
+    match error {
+        SendError::HandlerError(vault::Error::AlreadyBootstrapped) => Error::AlreadyBootstrapped,
+        _ => Error::Vault,
+    }
+}
+
+/// Build the custody record and hand it to the vault, which stores it in the
+/// same transaction as the root key.
+async fn finalize_bootstrap(
+    vault: &ActorRef<Vault>,
+    contributions: &mut Contributions,
+) -> Result<(), Error> {
+    let total = contributions.len();
+    let threshold = shamir::shamir_threshold(total).ok_or_else(|| committee_error(total))?;
+
+    let mut seal_key = KeyCell::new_secure_random();
+    let mut shares = shamir::split_key(threshold, total, &mut seal_key, UnwrapErr(SysRng))
+        .map_err(|error| Error::Shamir(error.to_string()))?;
+
+    if shares.len() < total {
+        return Err(Error::Shamir("missing share for operator".to_owned()));
+    }
+
+    let mut encrypted = Vec::with_capacity(total);
+    for ((operator_id, passphrase), share) in contributions.0.iter_mut().zip(shares.iter_mut()) {
+        let share = share.read_inline(|share| encrypt_share(passphrase, share))?;
+        encrypted.push((*operator_id, share));
+    }
+
+    vault
+        .ask(Bootstrap {
+            seal_key,
+            custody: Some(CustodyRecord {
+                threshold,
+                shares: encrypted,
+            }),
+        })
+        .await
+        .map_err(|error| bootstrap_error(&error))
+}
+
+/// Reconstruct the seal key from the contributed passphrases and unseal.
+async fn finalize_unseal(
+    db: &db::DatabasePool,
+    custody: &Arc<dyn CustodyStore>,
+    vault: &ActorRef<Vault>,
+    threshold: usize,
+    contributions: &mut Contributions,
+) -> Result<(), Error> {
+    let stored = {
+        let mut conn = db.get().await?;
+        custody
+            .shares(&mut conn, &contributions.operators())
+            .await?
+    };
+
+    let mut plaintext = Vec::with_capacity(stored.len());
+    for ((_, passphrase), share) in contributions.0.iter_mut().zip(stored) {
+        plaintext.push(decrypt_share(passphrase, share)?);
+    }
+
+    let seal_key = shamir::combine_shares(threshold, &mut plaintext)
+        .map_err(|error| Error::Shamir(error.to_string()))?;
+
+    vault
+        .ask(TryUnseal { seal_key })
+        .await
+        .map_err(|_| Error::Vault)
+}
+
+#[messages]
+impl VaultCoordinator {
+    /// Announce how many operators will contribute to the bootstrap.
+    ///
+    /// The declaring operator may re-declare to restart the ceremony; that is
+    /// the only way to release a committee whose members never all show up.
+    #[message]
+    pub fn start_bootstrap(
+        &mut self,
+        operator_id: OperatorId,
+        declared_count: usize,
+    ) -> Result<(), Error> {
+        if shamir::shamir_threshold(declared_count).is_none() {
+            return Err(committee_error(declared_count));
+        }
+
+        match &self.state {
+            CoordinatorState::Unsealing { .. } => return Err(Error::AlreadyUnsealing),
+            CoordinatorState::Bootstrapping { declarer, .. } if *declarer != operator_id => {
+                return Err(Error::AlreadyBootstrapping);
+            }
+            CoordinatorState::Bootstrapping { .. } | CoordinatorState::Idle => {}
+        }
+
+        self.state = CoordinatorState::Bootstrapping {
+            declarer: operator_id,
+            declared_count,
+            contributions: Contributions::default(),
+            retryable: false,
+        };
+        Ok(())
+    }
+
+    #[message]
+    pub async fn contribute_bootstrap(
+        &mut self,
+        operator_id: OperatorId,
+        passphrase: SafeCell<Vec<u8>>,
+    ) -> Result<bool, Error> {
+        let CoordinatorState::Bootstrapping {
+            declared_count,
+            contributions,
+            retryable,
+            ..
+        } = &mut self.state
+        else {
+            return Err(Error::NotBootstrapping);
+        };
+
+        if contributions.contains(operator_id) && !*retryable {
+            return Err(Error::DuplicateContribution);
+        }
+        contributions.put(operator_id, passphrase);
+        *retryable = false;
+
+        if contributions.len() < *declared_count {
+            return Ok(false);
+        }
+
+        let state = std::mem::replace(&mut self.state, CoordinatorState::Idle);
+        let CoordinatorState::Bootstrapping {
+            declarer,
+            declared_count,
+            mut contributions,
+            ..
+        } = state
+        else {
+            unreachable!("state was matched as Bootstrapping above")
+        };
+
+        match finalize_bootstrap(&self.vault, &mut contributions).await {
+            Ok(()) => Ok(true),
+            Err(error) => {
+                self.state = CoordinatorState::Bootstrapping {
+                    declarer,
+                    declared_count,
+                    contributions,
+                    retryable: true,
+                };
+                Err(error)
+            }
+        }
+    }
+
+    #[message]
+    pub async fn contribute_unseal(
+        &mut self,
+        operator_id: OperatorId,
+        passphrase: SafeCell<Vec<u8>>,
+    ) -> Result<bool, Error> {
+        if matches!(self.state, CoordinatorState::Idle) {
+            let threshold = {
+                let mut conn = self.db.get().await?;
+                self.custody.threshold(&mut conn).await?
+            };
+            self.state = CoordinatorState::Unsealing {
+                threshold,
+                contributions: Contributions::default(),
+                retryable: false,
+            };
+        }
+
+        let CoordinatorState::Unsealing {
+            threshold,
+            contributions,
+            retryable,
+        } = &mut self.state
+        else {
+            return Err(Error::AlreadyBootstrapping);
+        };
+
+        if contributions.contains(operator_id) && !*retryable {
+            return Err(Error::DuplicateContribution);
+        }
+        contributions.put(operator_id, passphrase);
+        *retryable = false;
+
+        if contributions.len() < *threshold {
+            return Ok(false);
+        }
+
+        let state = std::mem::replace(&mut self.state, CoordinatorState::Idle);
+        let CoordinatorState::Unsealing {
+            threshold,
+            mut contributions,
+            ..
+        } = state
+        else {
+            unreachable!("state was matched as Unsealing above")
+        };
+
+        match finalize_unseal(
+            &self.db,
+            &self.custody,
+            &self.vault,
+            threshold,
+            &mut contributions,
+        )
+        .await
+        {
+            Ok(()) => Ok(true),
+            Err(error) => {
+                self.state = CoordinatorState::Unsealing {
+                    threshold,
+                    contributions,
+                    retryable: true,
+                };
+                Err(error)
+            }
+        }
+    }
+}

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

@@ -1,13 +1,12 @@
-use std::sync::Arc;
-
-use thiserror::Error;
-
 use crate::{
     actors::GlobalActors,
     context::tls::TlsManager,
     db::{self},
 };
 
+use std::sync::Arc;
+use thiserror::Error;
+
 pub mod tls;
 
 #[derive(Error, Debug)]
@@ -31,16 +30,16 @@ pub enum InitError {
     Io(#[from] std::io::Error),
 }
 
-pub struct _ServerContextInner {
+pub struct __ServerContextInner {
     pub db: db::DatabasePool,
     pub tls: TlsManager,
     pub actors: GlobalActors,
 }
 #[derive(Clone)]
-pub struct ServerContext(Arc<_ServerContextInner>);
+pub struct ServerContext(Arc<__ServerContextInner>);
 
 impl std::ops::Deref for ServerContext {
-    type Target = _ServerContextInner;
+    type Target = __ServerContextInner;
 
     fn deref(&self) -> &Self::Target {
         &self.0
@@ -49,7 +48,7 @@ impl std::ops::Deref for ServerContext {
 
 impl ServerContext {
     pub async fn new(db: db::DatabasePool) -> Result<Self, InitError> {
-        Ok(Self(Arc::new(_ServerContextInner {
+        Ok(Self(Arc::new(__ServerContextInner {
             actors: GlobalActors::spawn(db.clone()).await?,
             tls: TlsManager::new(db.clone()).await?,
             db,

server/crates/arbiter-server/src/context/tls.rs

@@ -1,17 +1,3 @@
-use std::{net::{IpAddr, Ipv4Addr}, string::FromUtf8Error};
-
-use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper as _};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-
-use pem::Pem;
-use rcgen::{
-    BasicConstraints, Certificate, CertificateParams, CertifiedIssuer, DistinguishedName, DnType,
-    IsCa, Issuer, KeyPair, KeyUsagePurpose, SanType,
-};
-use rustls::pki_types::pem::PemObject;
-use thiserror::Error;
-use tonic::transport::CertificateDer;
-
 use crate::db::{
     self,
     models::{NewTlsHistory, TlsHistory},
@@ -21,10 +7,23 @@ use crate::db::{
     },
 };
 
+use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper as _};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use pem::Pem;
+use rcgen::{
+    BasicConstraints, Certificate, CertificateParams, CertifiedIssuer, DistinguishedName, DnType,
+    IsCa, Issuer, KeyPair, KeyUsagePurpose, SanType,
+};
+use rustls::pki_types::pem::PemObject;
+use std::{net::Ipv4Addr, string::FromUtf8Error};
+use thiserror::Error;
+use tonic::transport::CertificateDer;
+
 const ENCODE_CONFIG: pem::EncodeConfig = {
-    let line_ending = match cfg!(target_family = "windows") {
+    let line_ending = if cfg!(target_family = "windows") {
-        true => pem::LineEnding::CRLF,
+        pem::LineEnding::CRLF
-        false => pem::LineEnding::LF,
+    } else {
+        pem::LineEnding::LF
     };
     pem::EncodeConfig::new().set_line_ending(line_ending)
 };
@@ -52,11 +51,14 @@ pub enum InitError {
 
 pub type PemCert = String;
 
-pub fn encode_cert_to_pem(cert: &CertificateDer) -> PemCert {
+pub fn encode_cert_to_pem(cert: &CertificateDer<'_>) -> PemCert {
     pem::encode_config(&Pem::new("CERTIFICATE", cert.to_vec()), ENCODE_CONFIG)
 }
 
-#[allow(unused)]
+#[expect(
+    unused,
+    reason = "may be needed for future cert rotation implementation"
+)]
 struct SerializedTls {
     cert_pem: PemCert,
     cert_key_pem: String,
@@ -85,7 +87,7 @@ impl TlsCa {
 
         let cert_key_pem = certified_issuer.key().serialize_pem();
 
-        #[allow(
+        #[expect(
             clippy::unwrap_used,
             reason = "Broken cert couldn't bootstrap server anyway"
         )]
@@ -124,7 +126,11 @@ impl TlsCa {
         })
     }
 
-    #[allow(unused)]
+    #[expect(
+        unused,
+        clippy::unnecessary_wraps,
+        reason = "may be needed for future cert rotation implementation"
+    )]
     fn serialize(&self) -> Result<SerializedTls, InitError> {
         let cert_key_pem = self.issuer.key().serialize_pem();
         Ok(SerializedTls {
@@ -133,7 +139,10 @@ impl TlsCa {
         })
     }
 
-    #[allow(unused)]
+    #[expect(
+        unused,
+        reason = "may be needed for future cert rotation implementation"
+    )]
     fn try_deserialize(cert_pem: &str, cert_key_pem: &str) -> Result<Self, InitError> {
         let keypair =
             KeyPair::from_pem(cert_key_pem).map_err(InitError::KeyDeserializationError)?;
@@ -165,28 +174,26 @@ impl TlsManager {
 
         {
             let mut conn = db.get().await?;
-            conn.transaction(|conn| {
+            conn.transaction(async |conn| {
-                Box::pin(async {
+                let new_tls_history = NewTlsHistory {
-                    let new_tls_history = NewTlsHistory {
+                    cert: new_cert.cert.pem(),
-                        cert: new_cert.cert.pem(),
+                    cert_key: new_cert.cert_key.serialize_pem(),
-                        cert_key: new_cert.cert_key.serialize_pem(),
+                    ca_cert: encode_cert_to_pem(&ca.cert),
-                        ca_cert: encode_cert_to_pem(&ca.cert),
+                    ca_key: ca.issuer.key().serialize_pem(),
-                        ca_key: ca.issuer.key().serialize_pem(),
+                };
-                    };
 
-                    let inserted_tls_history: i32 = diesel::insert_into(tls_history::table)
+                let inserted_tls_history: i32 = diesel::insert_into(tls_history::table)
-                        .values(&new_tls_history)
+                    .values(&new_tls_history)
-                        .returning(tls_history::id)
+                    .returning(tls_history::id)
-                        .get_result(conn)
+                    .get_result(&mut *conn)
-                        .await?;
+                    .await?;
 
-                    diesel::update(arbiter_settings::table)
+                diesel::update(arbiter_settings::table)
-                        .set(arbiter_settings::tls_id.eq(inserted_tls_history))
+                    .set(arbiter_settings::tls_id.eq(inserted_tls_history))
-                        .execute(conn)
+                    .execute(&mut *conn)
-                        .await?;
+                    .await?;
 
-                    Result::<_, diesel::result::Error>::Ok(())
+                Result::<_, diesel::result::Error>::Ok(())
-                })
             })
             .await?;
         }
@@ -234,10 +241,10 @@ impl TlsManager {
         }
     }
 
-    pub fn cert(&self) -> &CertificateDer<'static> {
+    pub const fn cert(&self) -> &CertificateDer<'static> {
         &self.cert
     }
-    pub fn ca_cert(&self) -> &CertificateDer<'static> {
+    pub const fn ca_cert(&self) -> &CertificateDer<'static> {
         &self.ca_cert
     }
 

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

@@ -0,0 +1,3 @@
+pub mod v1;
+
+pub use v1::*;

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

@@ -0,0 +1,101 @@
+use argon2::password_hash::Salt as ArgonSalt;
+use rand::{
+    Rng as _, SeedableRng,
+    rngs::{StdRng, SysRng},
+};
+
+pub const ROOT_KEY_TAG: &[u8] = b"arbiter/seal/v1";
+pub const TAG: &[u8] = b"arbiter/private-key/v1";
+
+pub const NONCE_LENGTH: usize = 24;
+
+#[derive(Default)]
+pub struct Nonce(pub [u8; NONCE_LENGTH]);
+impl Nonce {
+    pub fn increment(&mut self) {
+        for i in (0..self.0.len()).rev() {
+            if let Some(byte) = self.0.get_mut(i) {
+                if *byte == 0xFF {
+                    *byte = 0;
+                } else {
+                    *byte += 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 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).expect("Rng failure is unrecoverable and should panic");
+    rng.fill_bytes(&mut salt);
+    salt
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::crypto::derive_key;
+    use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+
+    #[test]
+    fn derive_seal_key_deterministic() {
+        static PASSWORD: &[u8] = b"password";
+        let mut password = SafeCell::new(PASSWORD.to_vec());
+        let salt = generate_salt();
+
+        let mut key1 = derive_key(&mut password, &salt);
+        let mut key2 = derive_key(&mut password, &salt);
+
+        let key1_reader = key1.0.read();
+        let key2_reader = key2.0.read();
+
+        assert_eq!(&*key1_reader, &*key2_reader);
+    }
+
+    #[test]
+    fn successful_derive() {
+        static PASSWORD: &[u8] = b"password";
+        let mut password = SafeCell::new(PASSWORD.to_vec());
+        let salt = generate_salt();
+
+        let mut key = derive_key(&mut password, &salt);
+        let key_reader = key.0.read();
+
+        assert_ne!(key_reader.as_slice(), &[0u8; 32][..]);
+    }
+
+    #[test]
+    // We should fuzz this
+    pub fn 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/crypto/integrity/mod.rs

@@ -0,0 +1,3 @@
+pub mod v1;
+
+pub use v1::*;

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

@@ -0,0 +1,387 @@
+use crate::{
+    actors::vault::{self, GetState, SignIntegrity, Vault, VerifyIntegrity},
+    db::{
+        self,
+        models::{IntegrityEnvelope, NewIntegrityEnvelope},
+        schema::integrity_envelope,
+    },
+};
+use arbiter_crypto::hashing::Hashable;
+
+use diesel::{ExpressionMethods as _, QueryDsl, dsl::insert_into, sqlite::Sqlite};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use hmac::Hmac;
+use kameo::{actor::ActorRef, error::SendError};
+use sha2::{Digest as _, Sha256};
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("Database error: {0}")]
+    Database(#[from] db::DatabaseError),
+
+    #[error("Vault error: {0}")]
+    Vault(#[from] vault::Error),
+
+    #[error("Vault mailbox error")]
+    VaultSend,
+
+    #[error("Integrity envelope is missing for entity {entity_kind}")]
+    MissingEnvelope { entity_kind: &'static str },
+
+    #[error(
+        "Integrity payload version mismatch for entity {entity_kind}: expected {expected}, found {found}"
+    )]
+    PayloadVersionMismatch {
+        entity_kind: &'static str,
+        expected: i32,
+        found: i32,
+    },
+
+    #[error("Integrity MAC mismatch for entity {entity_kind}")]
+    MacMismatch { entity_kind: &'static str },
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum AttestationStatus {
+    Attested,
+    Unavailable,
+}
+
+pub const CURRENT_PAYLOAD_VERSION: i32 = 1;
+pub const INTEGRITY_SUBKEY_TAG: &[u8] = b"arbiter/db-integrity-key/v1";
+
+pub type HmacSha256 = Hmac<Sha256>;
+
+pub trait Integrable: Hashable {
+    const KIND: &'static str;
+    const VERSION: i32 = 1;
+}
+
+fn payload_hash(payload: &impl Hashable) -> [u8; 32] {
+    let mut hasher = Sha256::new();
+    payload.hash(&mut hasher);
+    hasher.finalize().into()
+}
+
+fn push_len_prefixed(out: &mut Vec<u8>, bytes: &[u8]) {
+    #[expect(
+        clippy::cast_possible_truncation,
+        clippy::as_conversions,
+        reason = "fixme! #85"
+    )]
+    out.extend_from_slice(&(bytes.len() as u32).to_be_bytes());
+    out.extend_from_slice(bytes);
+}
+
+fn build_mac_input(
+    entity_kind: &str,
+    entity_id: &[u8],
+    payload_version: i32,
+    payload_hash: &[u8; 32],
+) -> Vec<u8> {
+    let mut out = Vec::with_capacity(8 + entity_kind.len() + entity_id.len() + 32);
+    push_len_prefixed(&mut out, entity_kind.as_bytes());
+    push_len_prefixed(&mut out, entity_id);
+    out.extend_from_slice(&payload_version.to_be_bytes());
+    out.extend_from_slice(payload_hash);
+    out
+}
+
+pub trait IntoId {
+    fn into_id(self) -> Vec<u8>;
+}
+
+impl IntoId for i32 {
+    fn into_id(self) -> Vec<u8> {
+        self.to_be_bytes().to_vec()
+    }
+}
+
+impl IntoId for &'_ [u8] {
+    fn into_id(self) -> Vec<u8> {
+        self.to_vec()
+    }
+}
+
+pub async fn sign_entity<E: Integrable>(
+    conn: &mut impl AsyncConnection<Backend = Sqlite>,
+    vault: &ActorRef<Vault>,
+    entity: &E,
+    entity_id: impl IntoId,
+) -> Result<(), Error> {
+    let payload_hash = payload_hash(&entity);
+
+    let entity_id = entity_id.into_id();
+
+    let mac_input = build_mac_input(E::KIND, &entity_id, E::VERSION, &payload_hash);
+
+    let (key_version, mac) =
+        vault
+            .ask(SignIntegrity { mac_input })
+            .await
+            .map_err(|err| match err {
+                SendError::HandlerError(inner) => Error::Vault(inner),
+                _ => Error::VaultSend,
+            })?;
+
+    insert_into(integrity_envelope::table)
+        .values(NewIntegrityEnvelope {
+            entity_kind: E::KIND.to_owned(),
+            entity_id,
+            payload_version: E::VERSION,
+            key_version,
+            mac: mac.clone(),
+        })
+        .on_conflict((
+            integrity_envelope::entity_id,
+            integrity_envelope::entity_kind,
+        ))
+        .do_update()
+        .set((
+            integrity_envelope::payload_version.eq(E::VERSION),
+            integrity_envelope::key_version.eq(key_version),
+            integrity_envelope::mac.eq(mac),
+        ))
+        .execute(conn)
+        .await
+        .map_err(db::DatabaseError::from)?;
+
+    Ok(())
+}
+
+pub async fn verify_entity<E: Integrable>(
+    conn: &mut impl AsyncConnection<Backend = Sqlite>,
+    vault: &ActorRef<Vault>,
+    entity: &E,
+    entity_id: impl IntoId,
+) -> Result<AttestationStatus, Error> {
+    let entity_id = entity_id.into_id();
+    let envelope: IntegrityEnvelope = integrity_envelope::table
+        .filter(integrity_envelope::entity_kind.eq(E::KIND))
+        .filter(integrity_envelope::entity_id.eq(&entity_id))
+        .first(conn)
+        .await
+        .map_err(|err| match err {
+            diesel::result::Error::NotFound => Error::MissingEnvelope {
+                entity_kind: E::KIND,
+            },
+            other => Error::Database(db::DatabaseError::from(other)),
+        })?;
+
+    if envelope.payload_version != E::VERSION {
+        return Err(Error::PayloadVersionMismatch {
+            entity_kind: E::KIND,
+            expected: E::VERSION,
+            found: envelope.payload_version,
+        });
+    }
+
+    let payload_hash = payload_hash(&entity);
+    let mac_input = build_mac_input(E::KIND, &entity_id, envelope.payload_version, &payload_hash);
+
+    let result = vault
+        .ask(VerifyIntegrity {
+            mac_input,
+            expected_mac: envelope.mac,
+            key_version: envelope.key_version,
+        })
+        .await;
+
+    match result {
+        Ok(true) => Ok(AttestationStatus::Attested),
+        Ok(false) => Err(Error::MacMismatch {
+            entity_kind: E::KIND,
+        }),
+        Err(SendError::HandlerError(
+            vault::Error::Sealed | vault::Error::KeyVersionMismatch { .. },
+        )) => Ok(AttestationStatus::Unavailable),
+        Err(_) => Err(Error::VaultSend),
+    }
+}
+
+pub async fn is_signing_available(vault: &ActorRef<Vault>) -> Result<bool, Error> {
+    let state = vault.ask(GetState).await.map_err(|_| Error::VaultSend)?;
+    Ok(matches!(state, vault::VaultState::Unsealed))
+}
+
+#[cfg(test)]
+mod tests {
+    use std::sync::Arc;
+
+    use crate::db::custody::DieselCustodyStore;
+    use diesel::{ExpressionMethods as _, QueryDsl};
+    use diesel_async::RunQueryDsl;
+    use kameo::{actor::ActorRef, prelude::Spawn};
+
+    use crate::{
+        actors::{
+            GlobalActors,
+            vault::{Bootstrap, Vault},
+        },
+        crypto::KeyCell,
+        db::{self, schema},
+    };
+
+    use super::{Error, Integrable, sign_entity, verify_entity};
+    #[derive(Clone, arbiter_macros::Hashable)]
+    struct DummyEntity {
+        payload_version: i32,
+        payload: Vec<u8>,
+    }
+    impl Integrable for DummyEntity {
+        const KIND: &'static str = "dummy_entity";
+    }
+
+    async fn bootstrapped_vault(db: &db::DatabasePool) -> ActorRef<Vault> {
+        let actor = Vault::spawn(
+            Vault::new(
+                db.clone(),
+                GlobalActors::spawn_message_bus(),
+                Arc::new(DieselCustodyStore),
+            )
+            .await
+            .unwrap(),
+        );
+        actor
+            .ask(Bootstrap {
+                seal_key: KeyCell::from([0u8; 32]),
+                custody: None,
+            })
+            .await
+            .unwrap();
+        actor
+    }
+
+    #[tokio::test]
+    async fn sign_writes_envelope_and_verify_passes() {
+        const ENTITY_ID: &[u8] = b"entity-id-7";
+
+        let db = db::create_test_pool().await;
+        let vault = bootstrapped_vault(&db).await;
+        let mut conn = db.get().await.unwrap();
+
+        let entity = DummyEntity {
+            payload_version: 1,
+            payload: b"payload-v1".to_vec(),
+        };
+
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap();
+
+        let count: i64 = schema::integrity_envelope::table
+            .filter(schema::integrity_envelope::entity_kind.eq("dummy_entity"))
+            .filter(schema::integrity_envelope::entity_id.eq(ENTITY_ID))
+            .count()
+            .get_result(&mut conn)
+            .await
+            .unwrap();
+
+        assert_eq!(count, 1, "envelope row must be created exactly once");
+        verify_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap();
+    }
+
+    #[tokio::test]
+    async fn tampered_mac_fails_verification() {
+        const ENTITY_ID: &[u8] = b"entity-id-11";
+
+        let db = db::create_test_pool().await;
+        let vault = bootstrapped_vault(&db).await;
+        let mut conn = db.get().await.unwrap();
+
+        let entity = DummyEntity {
+            payload_version: 1,
+            payload: b"payload-v1".to_vec(),
+        };
+
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap();
+
+        diesel::update(schema::integrity_envelope::table)
+            .filter(schema::integrity_envelope::entity_kind.eq("dummy_entity"))
+            .filter(schema::integrity_envelope::entity_id.eq(ENTITY_ID))
+            .set(schema::integrity_envelope::mac.eq(vec![0u8; 32]))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+
+        let err = verify_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap_err();
+        assert!(matches!(err, Error::MacMismatch { .. }));
+    }
+
+    #[tokio::test]
+    async fn changed_payload_fails_verification() {
+        const ENTITY_ID: &[u8] = b"entity-id-21";
+
+        let db = db::create_test_pool().await;
+        let vault = bootstrapped_vault(&db).await;
+        let mut conn = db.get().await.unwrap();
+
+        let entity = DummyEntity {
+            payload_version: 1,
+            payload: b"payload-v1".to_vec(),
+        };
+
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap();
+
+        let tampered = DummyEntity {
+            payload: b"payload-v1-but-tampered".to_vec(),
+            ..entity
+        };
+
+        let err = verify_entity(&mut conn, &vault, &tampered, ENTITY_ID)
+            .await
+            .unwrap_err();
+        assert!(matches!(err, Error::MacMismatch { .. }));
+    }
+
+    #[tokio::test]
+    async fn key_version_mismatch_returns_unavailable_not_mac_mismatch() {
+        use crate::db::schema::integrity_envelope;
+        use super::AttestationStatus;
+
+        const ENTITY_ID: &[u8] = b"entity-id-rotation-test";
+
+        let db = db::create_test_pool().await;
+        let vault = bootstrapped_vault(&db).await;
+        let mut conn = db.get().await.unwrap();
+
+        let entity = DummyEntity {
+            payload_version: 1,
+            payload: b"payload-v1".to_vec(),
+        };
+
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap();
+
+        // Simulate key rotation: update the stored key_version to a stale value.
+        // After real rotation the vault's root_key_history_id would advance, but
+        // here we achieve the same mismatch by back-dating the envelope's key_version.
+        diesel::update(integrity_envelope::table)
+            .filter(integrity_envelope::entity_kind.eq("dummy_entity"))
+            .filter(integrity_envelope::entity_id.eq(ENTITY_ID))
+            .set(integrity_envelope::key_version.eq(0))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+
+        // Must NOT error — version mismatch is Unavailable, not tampered.
+        let status = verify_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .expect("key version mismatch must not be treated as an error");
+
+        assert_eq!(
+            status,
+            AttestationStatus::Unavailable,
+            "stale key_version must yield Unavailable, not MacMismatch"
+        );
+    }
+}

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

@@ -0,0 +1,170 @@
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use encryption::v1::Nonce;
+
+use argon2::{Algorithm, Argon2};
+use chacha20poly1305::{
+    AeadInPlace, Key, KeyInit as _, XChaCha20Poly1305, XNonce,
+    aead::{AeadMut, Error, Payload},
+};
+use rand::{
+    Rng as _, SeedableRng as _,
+    rngs::{StdRng, SysRng},
+};
+
+pub mod encryption;
+pub mod integrity;
+pub mod shamir;
+
+pub struct KeyCell(pub SafeCell<Key>);
+impl From<SafeCell<Key>> for KeyCell {
+    fn from(value: SafeCell<Key>) -> Self {
+        Self(value)
+    }
+}
+
+impl From<[u8; 32]> for KeyCell {
+    fn from(bytes: [u8; 32]) -> Self {
+        let cell = SafeCell::new_inline(|key: &mut Key| {
+            key.copy_from_slice(&bytes);
+        });
+        Self(cell)
+    }
+}
+
+impl TryFrom<SafeCell<Vec<u8>>> for KeyCell {
+    type Error = ();
+
+    fn try_from(mut value: SafeCell<Vec<u8>>) -> Result<Self, Self::Error> {
+        let value = value.read();
+        if value.len() != size_of::<Key>() {
+            return Err(());
+        }
+        let cell = SafeCell::new_inline(|cell_write: &mut Key| {
+            cell_write.copy_from_slice(&value);
+        });
+        Ok(Self(cell))
+    }
+}
+
+impl KeyCell {
+    pub fn new_secure_random() -> Self {
+        let key = SafeCell::new_inline(|key_buffer: &mut Key| {
+            let mut rng = StdRng::try_from_rng(&mut SysRng)
+                .expect("Rng failure is unrecoverable and should panic");
+            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();
+        let cipher = XChaCha20Poly1305::new(&key_reader);
+        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 SafeCell<Vec<u8>>,
+    ) -> Result<(), Error> {
+        let key_reader = self.0.read();
+        let cipher = XChaCha20Poly1305::new(&key_reader);
+        let nonce = XNonce::from_slice(nonce.0.as_ref());
+        let mut buffer = buffer.write();
+        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();
+        let mut cipher = XChaCha20Poly1305::new(&key_reader);
+        let nonce = XNonce::from_slice(nonce.0.as_ref());
+
+        let ciphertext = cipher.encrypt(
+            nonce,
+            Payload {
+                msg: plaintext.as_ref(),
+                aad: associated_data,
+            },
+        )?;
+        Ok(ciphertext)
+    }
+}
+
+/// Derive a fixed-length key from a passphrase using Argon2id.
+///
+/// The passphrase is borrowed so that callers can keep it in protected memory
+/// and reuse it across retries instead of handing over a copy.
+pub fn derive_key(password: &mut SafeCell<Vec<u8>>, salt: &[u8]) -> KeyCell {
+    let params = {
+        #[cfg(debug_assertions)]
+        {
+            argon2::Params::new(8, 1, 1, None).unwrap()
+        }
+
+        #[cfg(not(debug_assertions))]
+        {
+            argon2::Params::new(262_144, 3, 4, None).unwrap()
+        }
+    };
+
+    let hasher = Argon2::new(Algorithm::Argon2id, argon2::Version::V0x13, params);
+    let mut key = SafeCell::new(Key::default());
+    password.read_inline(|password_source| {
+        let mut key_buffer = key.write();
+        let key_buffer: &mut [u8] = key_buffer.as_mut();
+
+        hasher
+            .hash_password_into(password_source, salt, key_buffer)
+            .expect("Better fail completely than return a weak key");
+    });
+
+    key.into()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{
+        derive_key,
+        encryption::v1::{Nonce, generate_salt},
+    };
+    use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+
+    #[test]
+    fn encrypt_decrypt() {
+        static PASSWORD: &[u8] = b"password";
+        let mut password = SafeCell::new(PASSWORD.to_vec());
+        let salt = generate_salt();
+
+        let mut key = derive_key(&mut password, &salt);
+        let nonce = Nonce(*b"unique nonce 123 1231233");
+        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 = SafeCell::new(buffer);
+
+        key.decrypt_in_place(&nonce, associated_data, &mut buffer)
+            .unwrap();
+
+        let buffer = buffer.read();
+        assert_eq!(*buffer, b"secret data");
+    }
+}

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

@@ -0,0 +1,221 @@
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use rand_core::CryptoRng;
+use vsss_rs::Gf256;
+
+use crate::crypto::KeyCell;
+
+/// GF(256) addresses shares by a non-zero byte, so no committee can exceed 255.
+pub const MAX_COMMITTEE_SIZE: usize = 255;
+
+/// Errors returned by Shamir split/combine operations.
+#[derive(Debug, thiserror::Error)]
+pub enum ShamirError {
+    #[error("failed to split key: {0}")]
+    Split(String),
+    #[error("failed to combine shares: {0}")]
+    Combine(String),
+}
+
+/// Return the required threshold for a Shamir share pool of `committee_size`.
+///
+/// A pool of two is rejected: a majority of two is two, which gives each holder
+/// a veto over every unseal without giving either one recovery. That rejects no
+/// supported committee, because a two-operator vault must carry at least one
+/// recovery share and so never splits into a pool of two -- see
+/// `docs/ARCHITECTURE.md` 3.9.
+#[expect(
+    clippy::integer_division,
+    reason = "majority thresholds use integer arithmetic"
+)]
+#[must_use]
+pub const fn shamir_threshold(committee_size: usize) -> Option<usize> {
+    match committee_size {
+        0 | 2 => None,
+        size if size > MAX_COMMITTEE_SIZE => None,
+        1 => Some(1),
+        size => Some(size / 2 + 1),
+    }
+}
+
+/// Split a seal key into `total` shares, `threshold` of which reconstruct it.
+pub fn split_key(
+    threshold: usize,
+    total: usize,
+    key: &mut KeyCell,
+    rng: impl CryptoRng,
+) -> Result<Vec<SafeCell<Vec<u8>>>, ShamirError> {
+    if total == 0 || threshold == 0 || threshold > total || total == 2 || total > MAX_COMMITTEE_SIZE
+    {
+        return Err(ShamirError::Split(
+            "unsupported committee parameters".to_owned(),
+        ));
+    }
+
+    // Nothing to interpolate when one share suffices.
+    if threshold == 1 {
+        return Ok(key.0.read_inline(|key| {
+            std::iter::repeat_with(|| SafeCell::new(key.as_slice().to_vec()))
+                .take(total)
+                .collect()
+        }));
+    }
+
+    key.0.read_inline(|key| {
+        let key: &[u8; 32] = key
+            .as_slice()
+            .try_into()
+            .map_err(|_| ShamirError::Split("unexpected seal key length".to_owned()))?;
+
+        Gf256::split_array(threshold, total, key, rng)
+            .map(|shares| shares.into_iter().map(SafeCell::new).collect())
+            .map_err(|error| ShamirError::Split(format!("{error:?}")))
+    })
+}
+
+/// Combine shares back into the seal key.
+///
+/// `threshold` comes from storage rather than from the shapes of the shares:
+/// a one-of-one committee stores the key verbatim, and telling that apart by
+/// share length alone would misread any Shamir share that happened to be key
+/// sized.
+pub fn combine_shares(
+    threshold: usize,
+    shares: &mut [SafeCell<Vec<u8>>],
+) -> Result<KeyCell, ShamirError> {
+    if threshold == 0 {
+        return Err(ShamirError::Combine("threshold is zero".to_owned()));
+    }
+    if shares.len() < threshold {
+        return Err(ShamirError::Combine(
+            "not enough shares supplied".to_owned(),
+        ));
+    }
+
+    // Mirror of the one-of-one case in [`split_key`]: the share is the key.
+    if threshold == 1 {
+        let share = shares
+            .first_mut()
+            .ok_or_else(|| ShamirError::Combine("no shares supplied".to_owned()))?;
+        return reconstructed_key(share.read_inline(|share| SafeCell::new(share.clone())));
+    }
+
+    let mut gathered = SafeCell::new(Vec::with_capacity(shares.len()));
+    for share in shares.iter_mut() {
+        share.read_inline(|share| {
+            gathered.write_inline(|gathered| gathered.push(share.clone()));
+        });
+    }
+
+    let combined = gathered.read_inline(|gathered| {
+        Gf256::combine_array(gathered.as_slice())
+            .map(SafeCell::new)
+            .map_err(|error| ShamirError::Combine(format!("{error:?}")))
+    })?;
+
+    reconstructed_key(combined)
+}
+
+fn reconstructed_key(bytes: SafeCell<Vec<u8>>) -> Result<KeyCell, ShamirError> {
+    KeyCell::try_from(bytes)
+        .map_err(|()| ShamirError::Combine("unexpected reconstructed key length".to_owned()))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{MAX_COMMITTEE_SIZE, combine_shares, shamir_threshold, split_key};
+    use crate::crypto::KeyCell;
+    use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+    use rand::rngs::SysRng;
+    use rand_core::UnwrapErr;
+    use rstest::rstest;
+
+    fn key_bytes(mut key: KeyCell) -> [u8; 32] {
+        key.0.read_inline(|key| {
+            let mut bytes = [0u8; 32];
+            bytes.copy_from_slice(key.as_slice());
+            bytes
+        })
+    }
+
+    fn select(shares: &mut [SafeCell<Vec<u8>>], indexes: &[usize]) -> Vec<SafeCell<Vec<u8>>> {
+        indexes
+            .iter()
+            .filter_map(|index| {
+                shares
+                    .get_mut(*index)
+                    .map(|share| share.read_inline(|share| SafeCell::new(share.clone())))
+            })
+            .collect()
+    }
+
+    #[rstest]
+    #[case(&[0, 1])]
+    #[case(&[0, 2])]
+    #[case(&[1, 2])]
+    fn threshold_shares_reconstruct_fixed_key(#[case] indexes: &[usize]) {
+        let expected = [9_u8; 32];
+        let mut key = KeyCell::from(expected);
+        let rng = UnwrapErr(SysRng);
+        let mut shares = split_key(2, 3, &mut key, rng).expect("split should succeed");
+        let mut selected = select(&mut shares, indexes);
+        let combined = combine_shares(2, &mut selected).expect("combine should succeed");
+        assert_eq!(key_bytes(combined), expected);
+    }
+
+    #[test]
+    fn one_of_one_round_trips_a_fixed_size_key() {
+        let expected = [7_u8; 32];
+        let mut key = KeyCell::from(expected);
+        let rng = UnwrapErr(SysRng);
+        let mut shares = split_key(1, 1, &mut key, rng).expect("split should succeed");
+        let combined = combine_shares(1, &mut shares).expect("combine should succeed");
+        assert_eq!(key_bytes(combined), expected);
+    }
+
+    #[test]
+    fn fewer_shares_than_threshold_is_rejected() {
+        let mut key = KeyCell::from([3_u8; 32]);
+        let rng = UnwrapErr(SysRng);
+        let mut shares = split_key(3, 5, &mut key, rng).expect("split should succeed");
+        let mut selected = select(&mut shares, &[0, 1]);
+        assert!(
+            combine_shares(3, &mut selected).is_err(),
+            "two of three shares must not reconstruct the key"
+        );
+    }
+
+    #[rstest]
+    #[case(0, None)]
+    #[case(1, Some(1))]
+    #[case(2, None)]
+    #[case(3, Some(2))]
+    #[case(4, Some(3))]
+    #[case(MAX_COMMITTEE_SIZE, Some(128))]
+    #[case(MAX_COMMITTEE_SIZE + 1, None)]
+    fn committee_threshold_is_a_majority(
+        #[case] committee_size: usize,
+        #[case] expected: Option<usize>,
+    ) {
+        assert_eq!(shamir_threshold(committee_size), expected);
+    }
+
+    #[test]
+    fn oversized_committee_is_rejected_by_split() {
+        let mut key = KeyCell::from([1_u8; 32]);
+        let rng = UnwrapErr(SysRng);
+        assert!(
+            split_key(129, MAX_COMMITTEE_SIZE + 1, &mut key, rng).is_err(),
+            "committees above the GF(256) share limit must be rejected"
+        );
+    }
+
+    #[test]
+    fn two_operator_committee_is_explicitly_unsupported() {
+        let mut key = KeyCell::from([7_u8; 32]);
+        let rng = UnwrapErr(SysRng);
+        assert!(
+            split_key(2, 2, &mut key, rng).is_err(),
+            "two-operator committees must be rejected"
+        );
+    }
+}

server/crates/arbiter-server/src/db/custody.rs

@@ -0,0 +1,162 @@
+//! Storage for Shamir custody material: the reconstruction threshold and the
+//! per-operator encrypted shares of the vault seal key.
+//!
+//! Every query lives behind [`CustodyStore`] so that the actors above it hold
+//! no Diesel code of their own. [`CustodyStore::write_record`] borrows the
+//! caller's connection instead of taking one from the pool, which lets the
+//! vault write custody material inside the same transaction that stores the
+//! root key.
+
+use std::collections::HashMap;
+
+use async_trait::async_trait;
+use diesel::{ExpressionMethods as _, QueryDsl};
+use diesel_async::RunQueryDsl;
+
+use crate::db::{
+    self,
+    models::{OperatorId, SqliteTimestamp},
+    schema,
+};
+
+/// One Shamir share, encrypted under a key derived from its operator's passphrase.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct EncryptedShare {
+    pub ciphertext: Vec<u8>,
+    pub nonce: Vec<u8>,
+    pub salt: Vec<u8>,
+}
+
+/// Everything a bootstrap persists about custody, written as a single unit.
+#[derive(Debug)]
+pub struct CustodyRecord {
+    pub threshold: usize,
+    pub shares: Vec<(OperatorId, EncryptedShare)>,
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("Database query error: {0}")]
+    Query(#[from] diesel::result::Error),
+    #[error("Stored committee threshold is missing or out of range")]
+    BrokenThreshold,
+    #[error("Custody settings row is missing")]
+    MissingSettings,
+    #[error("No share stored for operator {0:?}")]
+    MissingShare(OperatorId),
+}
+
+#[async_trait]
+pub trait CustodyStore: std::fmt::Debug + Send + Sync {
+    /// Persist threshold and shares on the caller's connection, joining any
+    /// transaction the caller has already opened.
+    async fn write_record(
+        &self,
+        conn: &mut db::DatabaseConnection,
+        record: &CustodyRecord,
+    ) -> Result<(), Error>;
+
+    /// Number of shares required to reconstruct the seal key.
+    async fn threshold(&self, conn: &mut db::DatabaseConnection) -> Result<usize, Error>;
+
+    /// Load the shares of `operators` in one query, in the order requested.
+    async fn shares(
+        &self,
+        conn: &mut db::DatabaseConnection,
+        operators: &[OperatorId],
+    ) -> Result<Vec<EncryptedShare>, Error>;
+}
+
+/// The production [`CustodyStore`], backed by the `SQLite` schema.
+#[derive(Debug, Clone, Copy, Default)]
+pub struct DieselCustodyStore;
+
+#[async_trait]
+impl CustodyStore for DieselCustodyStore {
+    async fn write_record(
+        &self,
+        conn: &mut db::DatabaseConnection,
+        record: &CustodyRecord,
+    ) -> Result<(), Error> {
+        let threshold = i32::try_from(record.threshold).map_err(|_| Error::BrokenThreshold)?;
+
+        // SQLite has no batch form for REPLACE INTO in diesel, so the rows go
+        // in one at a time. The caller's transaction still makes them atomic.
+        let now = SqliteTimestamp::now();
+        for (operator_id, share) in &record.shares {
+            diesel::replace_into(schema::operator::table)
+                .values((
+                    schema::operator::id.eq(Some(*operator_id)),
+                    schema::operator::share.eq(&share.ciphertext),
+                    schema::operator::share_nonce.eq(&share.nonce),
+                    schema::operator::share_salt.eq(&share.salt),
+                    schema::operator::created_at.eq(now.clone()),
+                    schema::operator::updated_at.eq(now.clone()),
+                ))
+                .execute(&mut *conn)
+                .await?;
+        }
+
+        let updated = diesel::update(schema::arbiter_settings::table)
+            .set(schema::arbiter_settings::shamir_threshold.eq(Some(threshold)))
+            .execute(&mut *conn)
+            .await?;
+        if updated != 1 {
+            return Err(Error::MissingSettings);
+        }
+
+        Ok(())
+    }
+
+    async fn threshold(&self, conn: &mut db::DatabaseConnection) -> Result<usize, Error> {
+        let stored: Option<i32> = schema::arbiter_settings::table
+            .select(schema::arbiter_settings::shamir_threshold)
+            .first(conn)
+            .await?;
+
+        stored
+            .and_then(|value| usize::try_from(value).ok())
+            .filter(|threshold| *threshold > 0)
+            .ok_or(Error::BrokenThreshold)
+    }
+
+    async fn shares(
+        &self,
+        conn: &mut db::DatabaseConnection,
+        operators: &[OperatorId],
+    ) -> Result<Vec<EncryptedShare>, Error> {
+        let wanted: Vec<Option<OperatorId>> = operators.iter().copied().map(Some).collect();
+
+        let rows: Vec<(Option<OperatorId>, Vec<u8>, Vec<u8>, Vec<u8>)> = schema::operator::table
+            .filter(schema::operator::id.eq_any(wanted))
+            .select((
+                schema::operator::id,
+                schema::operator::share,
+                schema::operator::share_nonce,
+                schema::operator::share_salt,
+            ))
+            .load(conn)
+            .await?;
+
+        let mut found: HashMap<OperatorId, EncryptedShare> = rows
+            .into_iter()
+            .filter_map(|(id, ciphertext, nonce, salt)| {
+                id.map(|id| {
+                    (
+                        id,
+                        EncryptedShare {
+                            ciphertext,
+                            nonce,
+                            salt,
+                        },
+                    )
+                })
+            })
+            .collect();
+
+        operators
+            .iter()
+            .map(|id| found.remove(id).ok_or(Error::MissingShare(*id)))
+            .collect()
+    }
+}

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

@@ -5,10 +5,10 @@ use diesel_async::{
     sync_connection_wrapper::SyncConnectionWrapper,
 };
 use diesel_migrations::{EmbeddedMigrations, MigrationHarness, embed_migrations};
-
 use thiserror::Error;
 use tracing::info;
 
+pub mod custody;
 pub mod models;
 pub mod schema;
 
@@ -23,14 +23,14 @@ const MIGRATIONS: EmbeddedMigrations = embed_migrations!("migrations");
 
 #[derive(Error, Debug)]
 pub enum DatabaseSetupError {
-    #[error("Failed to determine home directory")]
+    #[error(transparent)]
-    HomeDir(std::io::Error),
+    ConcurrencySetup(diesel::result::Error),
 
     #[error(transparent)]
     Connection(diesel::ConnectionError),
 
-    #[error(transparent)]
+    #[error("Failed to determine home directory")]
-    ConcurrencySetup(diesel::result::Error),
+    HomeDir(std::io::Error),
 
     #[error(transparent)]
     Migration(Box<dyn std::error::Error + Send + Sync>),
@@ -41,10 +41,11 @@ pub enum DatabaseSetupError {
 
 #[derive(Error, Debug)]
 pub enum DatabaseError {
-    #[error("Database connection error")]
-    Pool(#[from] PoolError),
     #[error("Database query error")]
     Connection(#[from] diesel::result::Error),
+
+    #[error("Database connection error")]
+    Pool(#[from] PoolError),
 }
 
 #[tracing::instrument(level = "info")]
@@ -93,13 +94,16 @@ fn initialize_database(url: &str) -> Result<(), DatabaseSetupError> {
 }
 
 #[tracing::instrument(level = "info")]
+/// Creates a connection pool for the `SQLite` database.
+///
+/// # Panics
+/// Panics if the database path is not valid UTF-8.
 pub async fn create_pool(url: Option<&str>) -> Result<DatabasePool, DatabaseSetupError> {
     let database_url = url.map(String::from).unwrap_or(
-        #[allow(clippy::expect_used)]
         database_path()?
             .to_str()
             .expect("database path is not valid UTF-8")
-            .to_string(),
+            .to_owned(),
     );
 
     initialize_database(&database_url)?;
@@ -133,20 +137,57 @@ pub async fn create_pool(url: Option<&str>) -> Result<DatabasePool, DatabaseSetu
     Ok(pool)
 }
 
+#[mutants::skip]
+#[expect(clippy::missing_panics_doc, reason = "Tests oriented function")]
+/// Creates a test database pool with a temporary `SQLite` database file.
 pub async fn create_test_pool() -> DatabasePool {
     use rand::distr::{Alphanumeric, SampleString as _};
 
     let tempfile_name = Alphanumeric.sample_string(&mut rand::rng(), 16);
 
     let file = std::env::temp_dir().join(tempfile_name);
-    #[allow(clippy::expect_used)]
     let url = file
         .to_str()
         .expect("temp file path is not valid UTF-8")
-        .to_string();
+        .to_owned();
 
-    #[allow(clippy::expect_used)]
     create_pool(Some(&url))
         .await
         .expect("Failed to create test database pool")
 }
+
+#[cfg(test)]
+mod tests {
+    use diesel::{ExpressionMethods as _, result::DatabaseErrorKind};
+    use diesel_async::RunQueryDsl as _;
+
+    use super::*;
+
+    #[tokio::test]
+    async fn operator_share_salt_must_be_supplied_by_application() {
+        let pool = create_test_pool().await;
+        let mut conn = pool.get().await.expect("pool connection");
+
+        let operator_id = diesel::insert_into(schema::operator_identity::table)
+            .values(schema::operator_identity::public_key.eq(vec![1]))
+            .returning(schema::operator_identity::id)
+            .get_result::<i32>(&mut conn)
+            .await
+            .expect("insert operator identity");
+
+        let error = diesel::insert_into(schema::operator::table)
+            .values((
+                schema::operator::id.eq(operator_id),
+                schema::operator::share.eq(vec![2]),
+                schema::operator::share_nonce.eq(vec![3]),
+            ))
+            .execute(&mut conn)
+            .await
+            .expect_err("operator insert without an application-generated salt must fail");
+
+        assert!(matches!(
+            error,
+            diesel::result::Error::DatabaseError(DatabaseErrorKind::NotNullViolation, _)
+        ));
+    }
+}

server/crates/arbiter-server/src/db/models.rs

@@ -1,13 +1,14 @@
-#![allow(unused)]
+#![allow(
-#![allow(clippy::all)]
+    clippy::duplicated_attributes,
-
+    reason = "restructed's #[view] causes false positives"
+)]
 use crate::db::schema::{
     self, aead_encrypted, arbiter_settings, evm_basic_grant, evm_ether_transfer_grant,
     evm_ether_transfer_grant_target, evm_ether_transfer_limit, evm_token_transfer_grant,
     evm_token_transfer_log, evm_token_transfer_volume_limit, evm_transaction_log, evm_wallet,
-    root_key_history, tls_history,
+    integrity_envelope, root_key_history, tls_history,
 };
-use chrono::{DateTime, Utc};
+
 use diesel::{prelude::*, sqlite::Sqlite};
 use restructed::Models;
 
@@ -27,16 +28,16 @@ pub mod types {
     pub struct SqliteTimestamp(pub DateTime<Utc>);
     impl SqliteTimestamp {
         pub fn now() -> Self {
-            SqliteTimestamp(Utc::now())
+            Self(Utc::now())
         }
     }
 
-    impl From<chrono::DateTime<Utc>> for SqliteTimestamp {
+    impl From<DateTime<Utc>> for SqliteTimestamp {
-        fn from(dt: chrono::DateTime<Utc>) -> Self {
+        fn from(dt: DateTime<Utc>) -> Self {
-            SqliteTimestamp(dt)
+            Self(dt)
         }
     }
-    impl From<SqliteTimestamp> for chrono::DateTime<Utc> {
+    impl From<SqliteTimestamp> for DateTime<Utc> {
         fn from(ts: SqliteTimestamp) -> Self {
             ts.0
         }
@@ -47,6 +48,11 @@ pub mod types {
             &'b self,
             out: &mut diesel::serialize::Output<'b, '_, Sqlite>,
         ) -> diesel::serialize::Result {
+            #[expect(
+                clippy::cast_possible_truncation,
+                clippy::as_conversions,
+                reason = "fixme! #84; this will break up in 2038 :3"
+            )]
             let unix_timestamp = self.0.timestamp() as i32;
             out.set_value(unix_timestamp);
             Ok(IsNull::No)
@@ -69,43 +75,84 @@ pub mod types {
             let datetime =
                 DateTime::from_timestamp(unix_timestamp, 0).ok_or("Timestamp is out of bounds")?;
 
-            Ok(SqliteTimestamp(datetime))
+            Ok(Self(datetime))
         }
     }
 
-    /// Key algorithm stored in the `useragent_client.key_type` column.
+    macro_rules! declare_id {
-    /// Values must stay stable — they are persisted in the database.
+        ($name:ident) => {
-    #[derive(Debug, Clone, Copy, PartialEq, Eq, FromSqlRow, AsExpression, strum::FromRepr)]
+            #[derive(Debug, FromSqlRow, AsExpression, Clone, Hash, Copy, PartialEq, Eq)]
-    #[diesel(sql_type = Integer)]
+            #[diesel(sql_type = Integer)]
-    #[repr(i32)]
+            #[repr(transparent)] // hint compiler to optimize the wrapper struct away
-    pub enum KeyType {
+            pub struct $name(i32);
-        Ed25519 = 1,
+
-        EcdsaSecp256k1 = 2,
+            impl $name {
-        Rsa = 3,
+                pub const fn to_raw(self) -> i32 {
+                    self.0
+                }
+                pub const fn from_raw(raw: i32) -> Self {
+                    Self(raw)
+                }
+            }
+
+            impl FromSql<Integer, Sqlite> for $name {
+                fn from_sql(
+                    bytes: <Sqlite as diesel::backend::Backend>::RawValue<'_>,
+                ) -> diesel::deserialize::Result<Self> {
+                    FromSql::<Integer, Sqlite>::from_sql(bytes).map(Self)
+                }
+            }
+            impl ToSql<Integer, Sqlite> for $name {
+                fn to_sql<'b>(
+                    &'b self,
+                    out: &mut diesel::serialize::Output<'b, '_, Sqlite>,
+                ) -> diesel::serialize::Result {
+                    ToSql::<Integer, Sqlite>::to_sql(&self.0, out)
+                }
+            }
+
+            impl arbiter_crypto::hashing::Hashable for $name {
+                fn hash<H: arbiter_crypto::hashing::Digest>(&self, hasher: &mut H) {
+                    arbiter_crypto::hashing::Hashable::hash(&self.0, hasher);
+                }
+            }
+
+            impl crate::crypto::integrity::v1::IntoId for $name {
+                fn into_id(self) -> Vec<u8> {
+                    crate::crypto::integrity::v1::IntoId::into_id(self.0)
+                }
+            }
+        };
     }
 
-    impl ToSql<Integer, Sqlite> for KeyType {
+    declare_id!(ChainId);
-        fn to_sql<'b>(
-            &'b self,
-            out: &mut diesel::serialize::Output<'b, '_, Sqlite>,
-        ) -> diesel::serialize::Result {
-            out.set_value(*self as i32);
-            Ok(IsNull::No)
-        }
-    }
 
-    impl FromSql<Integer, Sqlite> for KeyType {
+    #[expect(
-        fn from_sql(
+        clippy::cast_sign_loss,
-            mut bytes: <Sqlite as diesel::backend::Backend>::RawValue<'_>,
+        clippy::cast_possible_truncation,
-        ) -> diesel::deserialize::Result<Self> {
+        clippy::as_conversions,
-            let Some(SqliteType::Long) = bytes.value_type() else {
+        reason = "safe because chain_id is stored as i32 but is guaranteed to be a valid ChainId by the API when creating grants"
-                return Err("Expected Integer for KeyType".into());
+    )]
-            };
+    const _: () = {
-            let discriminant = bytes.read_long();
+        impl From<ChainId> for alloy::primitives::ChainId {
-            KeyType::from_repr(discriminant as i32)
+            fn from(chain_id: ChainId) -> Self {
-                .ok_or_else(|| format!("Unknown KeyType discriminant: {discriminant}").into())
+                chain_id.0 as Self
+            }
         }
-    }
+        impl From<alloy::primitives::ChainId> for ChainId {
+            fn from(chain_id: alloy::primitives::ChainId) -> Self {
+                Self(chain_id as _)
+            }
+        }
+    };
+
+    declare_id!(OperatorId);
+    declare_id!(OperatorIdentityId);
+    declare_id!(AeadEncryptedId);
+    declare_id!(RootKeyHistoryId);
+    declare_id!(TlsHistoryId);
+    declare_id!(EvmWalletId);
+    declare_id!(ClientId);
 }
 pub use types::*;
 
@@ -118,12 +165,12 @@ pub use types::*;
 )]
 #[diesel(table_name = aead_encrypted, check_for_backend(Sqlite))]
 pub struct AeadEncrypted {
-    pub id: i32,
+    pub id: AeadEncryptedId,
     pub ciphertext: Vec<u8>,
     pub tag: Vec<u8>,
     pub current_nonce: Vec<u8>,
     pub schema_version: i32,
-    pub associated_root_key_id: i32, // references root_key_history.id
+    pub associated_root_key_id: RootKeyHistoryId,
     pub created_at: SqliteTimestamp,
 }
 
@@ -136,7 +183,7 @@ pub struct AeadEncrypted {
     attributes_with = "deriveless"
 )]
 pub struct RootKeyHistory {
-    pub id: i32,
+    pub id: RootKeyHistoryId,
     pub ciphertext: Vec<u8>,
     pub tag: Vec<u8>,
     pub root_key_encryption_nonce: Vec<u8>,
@@ -154,7 +201,7 @@ pub struct RootKeyHistory {
     attributes_with = "deriveless"
 )]
 pub struct TlsHistory {
-    pub id: i32,
+    pub id: TlsHistoryId,
     pub cert: String,
     pub cert_key: String, // PEM Encoded private key
     pub ca_cert: String,  // PEM Encoded certificate for cert signing
@@ -168,6 +215,7 @@ pub struct ArbiterSettings {
     pub id: i32,
     pub root_key_id: Option<i32>, // references root_key_history.id
     pub tls_id: Option<i32>,      // references tls_history.id
+    pub shamir_threshold: Option<i32>,
 }
 
 #[derive(Models, Queryable, Debug, Insertable, Selectable)]
@@ -179,7 +227,7 @@ pub struct ArbiterSettings {
     attributes_with = "deriveless"
 )]
 pub struct EvmWallet {
-    pub id: i32,
+    pub id: EvmWalletId,
     pub address: Vec<u8>,
     pub aead_encrypted_id: i32,
     pub created_at: SqliteTimestamp,
@@ -201,7 +249,7 @@ pub struct EvmWallet {
 )]
 pub struct EvmWalletAccess {
     pub id: i32,
-    pub wallet_id: i32,
+    pub wallet_id: EvmWalletId,
     pub client_id: i32,
     pub created_at: SqliteTimestamp,
 }
@@ -228,8 +276,7 @@ pub struct ProgramClientMetadataHistory {
 #[derive(Models, Queryable, Debug, Insertable, Selectable)]
 #[diesel(table_name = schema::program_client, check_for_backend(Sqlite))]
 pub struct ProgramClient {
-    pub id: i32,
+    pub id: ClientId,
-    pub nonce: i32,
     pub public_key: Vec<u8>,
     pub metadata_id: i32,
     pub created_at: SqliteTimestamp,
@@ -237,14 +284,23 @@ pub struct ProgramClient {
 }
 
 #[derive(Queryable, Debug)]
-#[diesel(table_name = schema::useragent_client, check_for_backend(Sqlite))]
+#[diesel(table_name = schema::operator_client, check_for_backend(Sqlite))]
-pub struct UseragentClient {
+pub struct OperatorClient {
-    pub id: i32,
+    pub id: OperatorIdentityId,
-    pub nonce: i32,
     pub public_key: Vec<u8>,
     pub created_at: SqliteTimestamp,
     pub updated_at: SqliteTimestamp,
-    pub key_type: KeyType,
+}
+
+#[derive(Queryable, Debug)]
+#[diesel(table_name = schema::operator, check_for_backend(Sqlite))]
+pub struct Operator {
+    pub id: OperatorId,
+    pub share: Vec<u8>,
+    pub share_nonce: Vec<u8>,
+    pub share_salt: Vec<u8>,
+    pub created_at: SqliteTimestamp,
+    pub updated_at: SqliteTimestamp,
 }
 
 #[derive(Models, Queryable, Debug, Insertable, Selectable)]
@@ -272,7 +328,7 @@ pub struct EvmEtherTransferLimit {
 pub struct EvmBasicGrant {
     pub id: i32,
     pub wallet_access_id: i32, // references evm_wallet_access.id
-    pub chain_id: i32,
+    pub chain_id: ChainId,
     pub valid_from: Option<SqliteTimestamp>,
     pub valid_until: Option<SqliteTimestamp>,
     pub max_gas_fee_per_gas: Option<Vec<u8>>,
@@ -295,7 +351,7 @@ pub struct EvmTransactionLog {
     pub id: i32,
     pub grant_id: i32,
     pub wallet_access_id: i32,
-    pub chain_id: i32,
+    pub chain_id: ChainId,
     pub eth_value: Vec<u8>,
     pub signed_at: SqliteTimestamp,
 }
@@ -370,9 +426,28 @@ pub struct EvmTokenTransferLog {
     pub id: i32,
     pub grant_id: i32,
     pub log_id: i32,
-    pub chain_id: i32,
+    pub chain_id: ChainId,
     pub token_contract: Vec<u8>,
     pub recipient_address: Vec<u8>,
     pub value: Vec<u8>,
     pub created_at: SqliteTimestamp,
 }
+
+#[derive(Models, Queryable, Debug, Insertable, Selectable)]
+#[diesel(table_name = integrity_envelope, check_for_backend(Sqlite))]
+#[view(
+    NewIntegrityEnvelope,
+    derive(Insertable),
+    omit(id, signed_at, created_at),
+    attributes_with = "deriveless"
+)]
+pub struct IntegrityEnvelope {
+    pub id: i32,
+    pub entity_kind: String,
+    pub entity_id: Vec<u8>,
+    pub payload_version: i32,
+    pub key_version: RootKeyHistoryId,
+    pub mac: Vec<u8>,
+    pub signed_at: SqliteTimestamp,
+    pub created_at: SqliteTimestamp,
+}

server/crates/arbiter-server/src/db/schema.rs

@@ -17,6 +17,7 @@ diesel::table! {
         id -> Integer,
         root_key_id -> Nullable<Integer>,
         tls_id -> Nullable<Integer>,
+        shamir_threshold -> Nullable<Integer>,
     }
 }
 
@@ -139,10 +140,42 @@ diesel::table! {
     }
 }
 
+diesel::table! {
+    integrity_envelope (id) {
+        id -> Integer,
+        entity_kind -> Text,
+        entity_id -> Binary,
+        payload_version -> Integer,
+        key_version -> Integer,
+        mac -> Binary,
+        signed_at -> Integer,
+        created_at -> Integer,
+    }
+}
+
+diesel::table! {
+    operator (id) {
+        id -> Nullable<Integer>,
+        share -> Binary,
+        share_nonce -> Binary,
+        share_salt -> Binary,
+        created_at -> Integer,
+        updated_at -> Integer,
+    }
+}
+
+diesel::table! {
+    operator_identity (id) {
+        id -> Integer,
+        public_key -> Binary,
+        created_at -> Integer,
+        updated_at -> Integer,
+    }
+}
+
 diesel::table! {
     program_client (id) {
         id -> Integer,
-        nonce -> Integer,
         public_key -> Binary,
         metadata_id -> Integer,
         created_at -> Integer,
@@ -173,17 +206,6 @@ diesel::table! {
     }
 }
 
-diesel::table! {
-    useragent_client (id) {
-        id -> Integer,
-        nonce -> Integer,
-        public_key -> Binary,
-        key_type -> Integer,
-        created_at -> Integer,
-        updated_at -> Integer,
-    }
-}
-
 diesel::joinable!(aead_encrypted -> root_key_history (associated_root_key_id));
 diesel::joinable!(arbiter_settings -> root_key_history (root_key_id));
 diesel::joinable!(arbiter_settings -> tls_history (tls_id));
@@ -202,6 +224,7 @@ diesel::joinable!(evm_transaction_log -> evm_wallet_access (wallet_access_id));
 diesel::joinable!(evm_wallet -> aead_encrypted (aead_encrypted_id));
 diesel::joinable!(evm_wallet_access -> evm_wallet (wallet_id));
 diesel::joinable!(evm_wallet_access -> program_client (client_id));
+diesel::joinable!(operator -> operator_identity (id));
 diesel::joinable!(program_client -> client_metadata (metadata_id));
 
 diesel::allow_tables_to_appear_in_same_query!(
@@ -219,8 +242,10 @@ diesel::allow_tables_to_appear_in_same_query!(
     evm_transaction_log,
     evm_wallet,
     evm_wallet_access,
+    integrity_envelope,
+    operator,
+    operator_identity,
     program_client,
     root_key_history,
     tls_history,
-    useragent_client,
 );

server/crates/arbiter-server/src/evm/abi.rs

@@ -45,7 +45,7 @@ sol! {
 
 sol! {
     /// Permit2 — Uniswap's canonical token approval manager.
-    /// Replaces per-contract ERC-20 approve() with a single approval hub.
+    /// Replaces per-contract ERC-20 `approve()` with a single approval hub.
     #[derive(Debug)]
     interface IPermit2 {
         struct TokenPermissions {

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

@@ -1,29 +1,38 @@
-pub mod abi;
-pub mod safe_signer;
-
-use alloy::{
-    consensus::TxEip1559,
-    primitives::{TxKind, U256},
-};
-use chrono::Utc;
-use diesel::{ExpressionMethods as _, QueryDsl as _, QueryResult, insert_into, sqlite::Sqlite};
 use diesel_async::{AsyncConnection, RunQueryDsl};
+use kameo::actor::ActorRef;
 
 use crate::{
+    actors::vault::Vault,
+    crypto::integrity,
     db::{
         self, DatabaseError,
         models::{
-            EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, NewEvmTransactionLog, SqliteTimestamp,
+            EvmBasicGrant, EvmEtherTransferGrant, EvmEtherTransferGrantTarget,
+            EvmEtherTransferLimit, EvmTokenTransferGrant, EvmTokenTransferVolumeLimit,
+            EvmWalletAccess, NewEvmBasicGrant, NewEvmTransactionLog, SqliteTimestamp,
         },
         schema::{self, evm_transaction_log},
     },
     evm::policies::{
-        DatabaseID, EvalContext, EvalViolation, FullGrant, Grant, Policy, SharedGrantSettings,
+        CombinedSettings, DatabaseID, EvalContext, EvalViolation, Grant, Policy,
-        SpecificGrant, SpecificMeaning, ether_transfer::EtherTransfer,
+        SharedGrantSettings, SpecificGrant, SpecificMeaning, VolumeRateLimit,
-        token_transfers::TokenTransfer,
+        ether_transfer::EtherTransfer, token_transfers::TokenTransfer,
     },
 };
 
+use alloy::{
+    consensus::TxEip1559,
+    primitives::{Address, TxKind, U256},
+};
+use chrono::Utc;
+use diesel::{
+    ExpressionMethods as _, OptionalExtension, QueryDsl as _, QueryResult, SelectableHelper,
+    insert_into, sqlite::Sqlite, update,
+};
+
+pub mod abi;
+pub mod safe_signer;
+
 pub mod policies;
 mod utils;
 
@@ -31,11 +40,14 @@ mod utils;
 #[derive(Debug, thiserror::Error)]
 pub enum PolicyError {
     #[error("Database error")]
-    Database(#[from] crate::db::DatabaseError),
+    Database(#[from] DatabaseError),
     #[error("Transaction violates policy: {0:?}")]
     Violations(Vec<EvalViolation>),
     #[error("No matching grant found")]
     NoMatchingGrant,
+
+    #[error("Integrity error: {0}")]
+    Integrity(#[from] integrity::Error),
 }
 
 #[derive(Debug, thiserror::Error)]
@@ -57,6 +69,15 @@ pub enum AnalyzeError {
     UnsupportedTransactionType,
 }
 
+#[derive(Debug, thiserror::Error)]
+pub enum ListError {
+    #[error("Database error")]
+    Database(#[from] DatabaseError),
+
+    #[error("Integrity verification failed for grant")]
+    Integrity(#[from] integrity::Error),
+}
+
 /// Controls whether a transaction should be executed or only validated
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum RunKind {
@@ -75,6 +96,14 @@ async fn check_shared_constraints(
     let mut violations = Vec::new();
     let now = Utc::now();
 
+    if shared.chain != context.chain {
+        violations.push(EvalViolation::MismatchingChainId {
+            expected: shared.chain,
+            actual: context.chain,
+        });
+        return Ok(violations);
+    }
+
     // Validity window
     if shared.valid_from.is_some_and(|t| now < t) || shared.valid_until.is_some_and(|t| now > t) {
         violations.push(EvalViolation::InvalidTime);
@@ -104,7 +133,7 @@ async fn check_shared_constraints(
             .get_result(conn)
             .await?;
 
-        if count >= rate_limit.count as i64 {
+        if count >= rate_limit.count.into() {
             violations.push(EvalViolation::RateLimitExceeded);
         }
     }
@@ -115,6 +144,7 @@ async fn check_shared_constraints(
 // Supporting only EIP-1559 transactions for now, but we can easily extend this to support legacy transactions if needed
 pub struct Engine {
     db: db::DatabasePool,
+    vault: ActorRef<Vault>,
 }
 
 impl Engine {
@@ -123,7 +153,10 @@ impl Engine {
         context: EvalContext,
         meaning: &P::Meaning,
         run_kind: RunKind,
-    ) -> Result<(), PolicyError> {
+    ) -> Result<(), PolicyError>
+    where
+        P::Settings: Clone,
+    {
         let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
 
         let grant = P::try_find_grant(&context, &mut conn)
@@ -131,10 +164,16 @@ impl Engine {
             .map_err(DatabaseError::from)?
             .ok_or(PolicyError::NoMatchingGrant)?;
 
-        let mut violations =
+        integrity::verify_entity(&mut conn, &self.vault, &grant.settings, grant.id).await?;
-            check_shared_constraints(&context, &grant.shared, grant.shared_grant_id, &mut conn)
+
-                .await
+        let mut violations = check_shared_constraints(
-                .map_err(DatabaseError::from)?;
+            &context,
+            &grant.settings.shared,
+            grant.common_settings_id,
+            &mut conn,
+        )
+        .await
+        .map_err(DatabaseError::from)?;
         violations.extend(
             P::evaluate(&context, meaning, &grant, &mut conn)
                 .await
@@ -143,25 +182,25 @@ impl Engine {
 
         if !violations.is_empty() {
             return Err(PolicyError::Violations(violations));
-        } else if run_kind == RunKind::Execution {
+        }
-            conn.transaction(|conn| {
-                Box::pin(async move {
-                    let log_id: i32 = insert_into(evm_transaction_log::table)
-                        .values(&NewEvmTransactionLog {
-                            grant_id: grant.shared_grant_id,
-                            wallet_access_id: context.target.id,
-                            chain_id: context.chain as i32,
-                            eth_value: utils::u256_to_bytes(context.value).to_vec(),
-                            signed_at: Utc::now().into(),
-                        })
-                        .returning(evm_transaction_log::id)
-                        .get_result(conn)
-                        .await?;
 
-                    P::record_transaction(&context, meaning, log_id, &grant, conn).await?;
+        if run_kind == RunKind::Execution {
+            conn.transaction(async |conn| {
+                let log_id: i32 = insert_into(evm_transaction_log::table)
+                    .values(&NewEvmTransactionLog {
+                        grant_id: grant.common_settings_id,
+                        wallet_access_id: context.target.id,
+                        chain_id: context.chain.into(),
+                        eth_value: utils::u256_to_bytes(context.value).to_vec(),
+                        signed_at: Utc::now().into(),
+                    })
+                    .returning(evm_transaction_log::id)
+                    .get_result(&mut *conn)
+                    .await?;
 
-                    QueryResult::Ok(())
+                P::record_transaction(&context, meaning, log_id, &grant, &mut *conn).await?;
-                })
+
+                QueryResult::Ok(())
             })
             .await
             .map_err(DatabaseError::from)?;
@@ -172,86 +211,248 @@ impl Engine {
 }
 
 impl Engine {
-    pub fn new(db: db::DatabasePool) -> Self {
+    pub const fn new(db: db::DatabasePool, vault: ActorRef<Vault>) -> Self {
-        Self { db }
+        Self { db, vault }
     }
 
     pub async fn create_grant<P: Policy>(
         &self,
-        full_grant: FullGrant<P::Settings>,
+        full_grant: CombinedSettings<P::Settings>,
-    ) -> Result<i32, DatabaseError> {
+    ) -> Result<i32, DatabaseError>
+    where
+        P::Settings: Clone,
+    {
         let mut conn = self.db.get().await?;
+        let vault = self.vault.clone();
 
         let id = conn
-            .transaction(|conn| {
+            .transaction(async |conn| {
-                Box::pin(async move {
+                use schema::evm_basic_grant;
-                    use schema::evm_basic_grant;
 
-                    let basic_grant: EvmBasicGrant = insert_into(evm_basic_grant::table)
+                #[expect(
-                        .values(&NewEvmBasicGrant {
+                    clippy::cast_possible_truncation,
-                            chain_id: full_grant.basic.chain as i32,
+                    clippy::cast_possible_wrap,
-                            wallet_access_id: full_grant.basic.wallet_access_id,
+                    clippy::as_conversions,
-                            valid_from: full_grant.basic.valid_from.map(SqliteTimestamp),
+                    reason = "fixme! #86"
-                            valid_until: full_grant.basic.valid_until.map(SqliteTimestamp),
+                )]
-                            max_gas_fee_per_gas: full_grant
+                let basic_grant: EvmBasicGrant = insert_into(evm_basic_grant::table)
-                                .basic
+                    .values(&NewEvmBasicGrant {
-                                .max_gas_fee_per_gas
+                        chain_id: full_grant.shared.chain.into(),
-                                .map(|fee| utils::u256_to_bytes(fee).to_vec()),
+                        wallet_access_id: full_grant.shared.wallet_access_id,
-                            max_priority_fee_per_gas: full_grant
+                        valid_from: full_grant.shared.valid_from.map(SqliteTimestamp),
-                                .basic
+                        valid_until: full_grant.shared.valid_until.map(SqliteTimestamp),
-                                .max_priority_fee_per_gas
+                        max_gas_fee_per_gas: full_grant
-                                .map(|fee| utils::u256_to_bytes(fee).to_vec()),
+                            .shared
-                            rate_limit_count: full_grant
+                            .max_gas_fee_per_gas
-                                .basic
+                            .map(|fee| utils::u256_to_bytes(fee).to_vec()),
-                                .rate_limit
+                        max_priority_fee_per_gas: full_grant
-                                .as_ref()
+                            .shared
-                                .map(|rl| rl.count as i32),
+                            .max_priority_fee_per_gas
-                            rate_limit_window_secs: full_grant
+                            .map(|fee| utils::u256_to_bytes(fee).to_vec()),
-                                .basic
+                        rate_limit_count: full_grant
-                                .rate_limit
+                            .shared
-                                .as_ref()
+                            .rate_limit
-                                .map(|rl| rl.window.num_seconds() as i32),
+                            .as_ref()
-                            revoked_at: None,
+                            .map(|rl| rl.count as i32),
-                        })
+                        rate_limit_window_secs: full_grant
-                        .returning(evm_basic_grant::all_columns)
+                            .shared
-                        .get_result(conn)
+                            .rate_limit
-                        .await?;
+                            .as_ref()
+                            .map(|rl| rl.window.num_seconds() as i32),
+                        revoked_at: None,
+                    })
+                    .returning(evm_basic_grant::all_columns)
+                    .get_result(&mut *conn)
+                    .await?;
 
-                    P::create_grant(&basic_grant, &full_grant.specific, conn).await
+                P::create_grant(&basic_grant, &full_grant.specific, &mut *conn).await?;
-                })
+
+                integrity::sign_entity(&mut *conn, &vault, &full_grant, basic_grant.id)
+                    .await
+                    .map_err(|_| diesel::result::Error::RollbackTransaction)?;
+
+                QueryResult::Ok(basic_grant.id)
             })
             .await?;
 
         Ok(id)
     }
 
-    pub async fn list_all_grants(&self) -> Result<Vec<Grant<SpecificGrant>>, DatabaseError> {
+    pub async fn revoke_grant(
-        let mut conn = self.db.get().await?;
+        &self,
+        basic_grant_id: i32,
+    ) -> Result<(), DatabaseError> {
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
+        let vault = self.vault.clone();
+
+        conn.transaction(async move |conn| {
+            use crate::db::schema::{
+                evm_basic_grant, evm_ether_transfer_grant, evm_ether_transfer_grant_target,
+                evm_ether_transfer_limit, evm_token_transfer_grant,
+                evm_token_transfer_volume_limit,
+            };
+
+            update(evm_basic_grant::table)
+                .filter(evm_basic_grant::id.eq(basic_grant_id))
+                .set(evm_basic_grant::revoked_at.eq(SqliteTimestamp(Utc::now())))
+                .execute(&mut *conn)
+                .await?;
+
+            let basic_grant: EvmBasicGrant = evm_basic_grant::table
+                .filter(evm_basic_grant::id.eq(basic_grant_id))
+                .select(EvmBasicGrant::as_select())
+                .first(&mut *conn)
+                .await?;
+
+            let shared = SharedGrantSettings::try_from_model(basic_grant)?;
+
+            if let Some(ether_grant) = evm_ether_transfer_grant::table
+                .filter(evm_ether_transfer_grant::basic_grant_id.eq(basic_grant_id))
+                .select(EvmEtherTransferGrant::as_select())
+                .first(&mut *conn)
+                .await
+                .optional()?
+            {
+                let target_rows: Vec<EvmEtherTransferGrantTarget> =
+                    evm_ether_transfer_grant_target::table
+                        .filter(evm_ether_transfer_grant_target::grant_id.eq(ether_grant.id))
+                        .select(EvmEtherTransferGrantTarget::as_select())
+                        .load(&mut *conn)
+                        .await?;
+                let targets: Vec<Address> = target_rows
+                    .into_iter()
+                    .filter_map(|target| {
+                        let arr: [u8; 20] = target.address.try_into().ok()?;
+                        Some(Address::from(arr))
+                    })
+                    .collect();
+
+                let limit: EvmEtherTransferLimit = evm_ether_transfer_limit::table
+                    .filter(evm_ether_transfer_limit::id.eq(ether_grant.limit_id))
+                    .select(EvmEtherTransferLimit::as_select())
+                    .first(&mut *conn)
+                    .await?;
+
+                let settings = CombinedSettings {
+                    shared: shared.clone(),
+                    specific: policies::ether_transfer::Settings {
+                        target: targets,
+                        limit: VolumeRateLimit {
+                            max_volume: utils::try_bytes_to_u256(&limit.max_volume).map_err(
+                                |err| {
+                                    diesel::result::Error::DeserializationError(Box::new(err))
+                                },
+                            )?,
+                            window: chrono::Duration::seconds(limit.window_secs.into()),
+                        },
+                    },
+                };
+
+                integrity::sign_entity(&mut *conn, &vault, &settings, basic_grant_id)
+                    .await
+                    .map_err(|_| diesel::result::Error::RollbackTransaction)?;
+
+                return QueryResult::Ok(());
+            }
+
+            if let Some(token_grant) = evm_token_transfer_grant::table
+                .filter(evm_token_transfer_grant::basic_grant_id.eq(basic_grant_id))
+                .select(EvmTokenTransferGrant::as_select())
+                .first(&mut *conn)
+                .await
+                .optional()?
+            {
+                let volume_limit_rows: Vec<EvmTokenTransferVolumeLimit> =
+                    evm_token_transfer_volume_limit::table
+                        .filter(evm_token_transfer_volume_limit::grant_id.eq(token_grant.id))
+                        .select(EvmTokenTransferVolumeLimit::as_select())
+                        .load(&mut *conn)
+                        .await?;
+                let volume_limits: Vec<VolumeRateLimit> = volume_limit_rows
+                    .into_iter()
+                    .map(|row| {
+                        Ok(VolumeRateLimit {
+                            max_volume: utils::try_bytes_to_u256(&row.max_volume).map_err(
+                                |err| {
+                                    diesel::result::Error::DeserializationError(Box::new(err))
+                                },
+                            )?,
+                            window: chrono::Duration::seconds(row.window_secs.into()),
+                        })
+                    })
+                    .collect::<QueryResult<Vec<_>>>()?;
+
+                let target: Option<Address> = match token_grant.receiver {
+                    None => None,
+                    Some(bytes) => {
+                        let arr: [u8; 20] = bytes.try_into().map_err(|_| {
+                            diesel::result::Error::DeserializationError(
+                                "Invalid receiver address length".into(),
+                            )
+                        })?;
+                        Some(Address::from(arr))
+                    }
+                };
+
+                let token_contract: [u8; 20] =
+                    token_grant.token_contract.clone().try_into().map_err(|_| {
+                        diesel::result::Error::DeserializationError(
+                            "Invalid token contract address length".into(),
+                        )
+                    })?;
+
+                let settings = CombinedSettings {
+                    shared,
+                    specific: policies::token_transfers::Settings {
+                        token_contract: Address::from(token_contract),
+                        target,
+                        volume_limits,
+                    },
+                };
+
+                integrity::sign_entity(&mut *conn, &vault, &settings, basic_grant_id)
+                    .await
+                    .map_err(|_| diesel::result::Error::RollbackTransaction)?;
+
+                return QueryResult::Ok(());
+            }
+
+            Err(diesel::result::Error::NotFound)
+        })
+        .await
+        .map_err(DatabaseError::from)
+    }
+
+    async fn list_one_kind<Kind: Policy, Y>(
+        &self,
+        conn: &mut impl AsyncConnection<Backend = Sqlite>,
+    ) -> Result<impl Iterator<Item = Grant<Y>>, ListError>
+    where
+        Y: From<Kind::Settings>,
+    {
+        let all_grants = Kind::find_all_grants(conn)
+            .await
+            .map_err(DatabaseError::from)?;
+
+        // Verify integrity of all grants before returning any results
+        for grant in &all_grants {
+            integrity::verify_entity(conn, &self.vault, &grant.settings, grant.id).await?;
+        }
+
+        Ok(all_grants.into_iter().map(|g| Grant {
+            id: g.id,
+            common_settings_id: g.common_settings_id,
+            settings: g.settings.generalize(),
+        }))
+    }
+
+    pub async fn list_all_grants(&self) -> Result<Vec<Grant<SpecificGrant>>, ListError> {
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
 
         let mut grants: Vec<Grant<SpecificGrant>> = Vec::new();
 
-        grants.extend(
+        grants.extend(self.list_one_kind::<EtherTransfer, _>(&mut conn).await?);
-            EtherTransfer::find_all_grants(&mut conn)
+        grants.extend(self.list_one_kind::<TokenTransfer, _>(&mut conn).await?);
-                .await?
-                .into_iter()
-                .map(|g| Grant {
-                    id: g.id,
-                    shared_grant_id: g.shared_grant_id,
-                    shared: g.shared,
-                    settings: SpecificGrant::EtherTransfer(g.settings),
-                }),
-        );
-        grants.extend(
-            TokenTransfer::find_all_grants(&mut conn)
-                .await?
-                .into_iter()
-                .map(|g| Grant {
-                    id: g.id,
-                    shared_grant_id: g.shared_grant_id,
-                    shared: g.shared,
-                    settings: SpecificGrant::TokenTransfer(g.settings),
-                }),
-        );
 
         Ok(grants)
     }
@@ -265,7 +466,7 @@ impl Engine {
         let TxKind::Call(to) = transaction.to else {
             return Err(VetError::ContractCreationNotSupported);
         };
-        let context = policies::EvalContext {
+        let context = EvalContext {
             target,
             chain: transaction.chain_id,
             to,
@@ -297,3 +498,388 @@ impl Engine {
         Err(VetError::UnsupportedTransactionType)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::sync::Arc;
+
+    use crate::db::custody::DieselCustodyStore;
+    use alloy::primitives::{Address, Bytes, U256, address};
+    use chrono::{Duration, Utc};
+    use diesel::{SelectableHelper, insert_into};
+    use diesel_async::RunQueryDsl;
+    use kameo::{actor::ActorRef, prelude::Spawn};
+    use rstest::rstest;
+
+    use crate::actors::{GlobalActors, vault::{Bootstrap, Vault}};
+    use crate::crypto::KeyCell;
+    use crate::crypto::integrity;
+    use crate::db::{
+        self, DatabaseConnection,
+        models::{
+            EvmBasicGrant, EvmWalletAccess, EvmWalletId, NewEvmBasicGrant, NewEvmTransactionLog,
+            SqliteTimestamp,
+        },
+        schema::{evm_basic_grant, evm_transaction_log},
+    };
+    use crate::evm::policies::ether_transfer::EtherTransfer;
+    use crate::evm::policies::{
+        CombinedSettings, EvalContext, EvalViolation, Policy, SharedGrantSettings,
+        TransactionRateLimit, VolumeRateLimit,
+    };
+
+    use super::check_shared_constraints;
+
+    const WALLET_ACCESS_ID: i32 = 1;
+    const CHAIN_ID: u64 = 1;
+    const RECIPIENT: Address = address!("1111111111111111111111111111111111111111");
+
+    fn context() -> EvalContext {
+        EvalContext {
+            target: EvmWalletAccess {
+                id: WALLET_ACCESS_ID,
+                wallet_id: EvmWalletId::from_raw(5),
+                client_id: 20,
+                created_at: SqliteTimestamp(Utc::now()),
+            },
+            chain: CHAIN_ID,
+            to: RECIPIENT,
+            value: U256::ZERO,
+            calldata: Bytes::new(),
+            max_fee_per_gas: 100,
+            max_priority_fee_per_gas: 10,
+        }
+    }
+
+    fn shared_settings() -> SharedGrantSettings {
+        SharedGrantSettings {
+            wallet_access_id: WALLET_ACCESS_ID,
+            chain: CHAIN_ID,
+            valid_from: None,
+            valid_until: None,
+            revoked_at: None,
+            max_gas_fee_per_gas: None,
+            max_priority_fee_per_gas: None,
+            rate_limit: None,
+        }
+    }
+
+    async fn insert_basic_grant(
+        conn: &mut DatabaseConnection,
+        shared: &SharedGrantSettings,
+    ) -> EvmBasicGrant {
+        #[expect(
+            clippy::cast_possible_truncation,
+            clippy::cast_possible_wrap,
+            clippy::as_conversions,
+            reason = "fixme! #86"
+        )]
+        insert_into(evm_basic_grant::table)
+            .values(NewEvmBasicGrant {
+                wallet_access_id: shared.wallet_access_id,
+                chain_id: shared.chain.into(),
+                valid_from: shared.valid_from.map(SqliteTimestamp),
+                valid_until: shared.valid_until.map(SqliteTimestamp),
+                max_gas_fee_per_gas: shared
+                    .max_gas_fee_per_gas
+                    .map(|fee| super::utils::u256_to_bytes(fee).to_vec()),
+                max_priority_fee_per_gas: shared
+                    .max_priority_fee_per_gas
+                    .map(|fee| super::utils::u256_to_bytes(fee).to_vec()),
+                rate_limit_count: shared.rate_limit.as_ref().map(|limit| limit.count as i32),
+                rate_limit_window_secs: shared
+                    .rate_limit
+                    .as_ref()
+                    .map(|limit| limit.window.num_seconds() as i32),
+                revoked_at: None,
+            })
+            .returning(EvmBasicGrant::as_select())
+            .get_result(conn)
+            .await
+            .unwrap()
+    }
+
+    #[rstest]
+    #[case::matching_chain(CHAIN_ID, false)]
+    #[case::mismatching_chain(CHAIN_ID + 1, true)]
+    #[tokio::test]
+    async fn check_shared_constraints_enforces_chain_id(
+        #[case] context_chain: u64,
+        #[case] expect_mismatch: bool,
+    ) {
+        let db = db::create_test_pool().await;
+        let mut conn = db.get().await.unwrap();
+
+        let context = EvalContext {
+            chain: context_chain,
+            ..context()
+        };
+
+        let violations = check_shared_constraints(&context, &shared_settings(), 999, &mut *conn)
+            .await
+            .unwrap();
+
+        assert_eq!(
+            violations
+                .iter()
+                .any(|violation| matches!(violation, EvalViolation::MismatchingChainId { .. })),
+            expect_mismatch
+        );
+
+        if expect_mismatch {
+            assert_eq!(violations.len(), 1);
+        } else {
+            assert!(violations.is_empty());
+        }
+    }
+
+    #[rstest]
+    #[case::valid_from_in_bounds(Some(Utc::now() - Duration::hours(1)), None, false)]
+    #[case::valid_from_out_of_bounds(Some(Utc::now() + Duration::hours(1)), None, true)]
+    #[case::valid_until_in_bounds(None, Some(Utc::now() + Duration::hours(1)), false)]
+    #[case::valid_until_out_of_bounds(None, Some(Utc::now() - Duration::hours(1)), true)]
+    #[tokio::test]
+    async fn check_shared_constraints_enforces_validity_window(
+        #[case] valid_from: Option<chrono::DateTime<Utc>>,
+        #[case] valid_until: Option<chrono::DateTime<Utc>>,
+        #[case] expect_invalid_time: bool,
+    ) {
+        let db = db::create_test_pool().await;
+        let mut conn = db.get().await.unwrap();
+
+        let shared = SharedGrantSettings {
+            valid_from,
+            valid_until,
+            ..shared_settings()
+        };
+
+        let violations = check_shared_constraints(&context(), &shared, 999, &mut *conn)
+            .await
+            .unwrap();
+
+        assert_eq!(
+            violations
+                .iter()
+                .any(|violation| matches!(violation, EvalViolation::InvalidTime)),
+            expect_invalid_time
+        );
+
+        if expect_invalid_time {
+            assert_eq!(violations.len(), 1);
+        } else {
+            assert!(violations.is_empty());
+        }
+    }
+
+    #[rstest]
+    #[case::max_fee_within_limit(Some(U256::from(100u64)), None, 100, 10, false)]
+    #[case::max_fee_exceeded(Some(U256::from(99u64)), None, 100, 10, true)]
+    #[case::priority_fee_within_limit(None, Some(U256::from(10u64)), 100, 10, false)]
+    #[case::priority_fee_exceeded(None, Some(U256::from(9u64)), 100, 10, true)]
+    #[tokio::test]
+    async fn check_shared_constraints_enforces_gas_fee_caps(
+        #[case] max_gas_fee_per_gas: Option<U256>,
+        #[case] max_priority_fee_per_gas: Option<U256>,
+        #[case] actual_max_fee_per_gas: u128,
+        #[case] actual_max_priority_fee_per_gas: u128,
+        #[case] expect_gas_limit_violation: bool,
+    ) {
+        let db = db::create_test_pool().await;
+        let mut conn = db.get().await.unwrap();
+
+        let context = EvalContext {
+            max_fee_per_gas: actual_max_fee_per_gas,
+            max_priority_fee_per_gas: actual_max_priority_fee_per_gas,
+            ..context()
+        };
+
+        let shared = SharedGrantSettings {
+            max_gas_fee_per_gas,
+            max_priority_fee_per_gas,
+            ..shared_settings()
+        };
+        let violations = check_shared_constraints(&context, &shared, 999, &mut *conn)
+            .await
+            .unwrap();
+
+        assert_eq!(
+            violations
+                .iter()
+                .any(|violation| matches!(violation, EvalViolation::GasLimitExceeded { .. })),
+            expect_gas_limit_violation
+        );
+
+        if expect_gas_limit_violation {
+            assert_eq!(violations.len(), 1);
+        } else {
+            assert!(violations.is_empty());
+        }
+    }
+
+    #[rstest]
+    #[case::under_rate_limit(2, false)]
+    #[case::at_rate_limit(1, true)]
+    #[tokio::test]
+    async fn check_shared_constraints_enforces_rate_limit(
+        #[case] rate_limit_count: u32,
+        #[case] expect_rate_limit_violation: bool,
+    ) {
+        let db = db::create_test_pool().await;
+        let mut conn = db.get().await.unwrap();
+
+        let shared = SharedGrantSettings {
+            rate_limit: Some(TransactionRateLimit {
+                count: rate_limit_count,
+                window: Duration::hours(1),
+            }),
+            ..shared_settings()
+        };
+
+        let basic_grant = insert_basic_grant(&mut conn, &shared).await;
+
+        insert_into(evm_transaction_log::table)
+            .values(NewEvmTransactionLog {
+                grant_id: basic_grant.id,
+                wallet_access_id: WALLET_ACCESS_ID,
+                chain_id: CHAIN_ID.into(),
+                eth_value: super::utils::u256_to_bytes(U256::ZERO).to_vec(),
+                signed_at: SqliteTimestamp(Utc::now()),
+            })
+            .execute(&mut *conn)
+            .await
+            .unwrap();
+
+        let violations = check_shared_constraints(&context(), &shared, basic_grant.id, &mut *conn)
+            .await
+            .unwrap();
+
+        assert_eq!(
+            violations
+                .iter()
+                .any(|violation| matches!(violation, EvalViolation::RateLimitExceeded)),
+            expect_rate_limit_violation
+        );
+
+        if expect_rate_limit_violation {
+            assert_eq!(violations.len(), 1);
+        } else {
+            assert!(violations.is_empty());
+        }
+    }
+
+    async fn bootstrapped_vault(db: &db::DatabasePool) -> ActorRef<Vault> {
+        let actor = Vault::spawn(
+            Vault::new(
+                db.clone(),
+                GlobalActors::spawn_message_bus(),
+                Arc::new(DieselCustodyStore),
+            )
+            .await
+            .unwrap(),
+        );
+        actor
+            .ask(Bootstrap {
+                seal_key: KeyCell::from([0u8; 32]),
+                custody: None,
+            })
+            .await
+            .unwrap();
+        actor
+    }
+
+    #[tokio::test]
+    async fn revoke_grant_preserves_revoked_integrity() {
+        use crate::db::schema::evm_basic_grant;
+        use diesel::ExpressionMethods as _;
+
+        let db = db::create_test_pool().await;
+        let vault = bootstrapped_vault(&db).await;
+        let engine = super::Engine::new(db.clone(), vault.clone());
+
+        let full_grant = CombinedSettings {
+            shared: SharedGrantSettings {
+                wallet_access_id: WALLET_ACCESS_ID,
+                chain: CHAIN_ID,
+                valid_from: None,
+                valid_until: None,
+                revoked_at: None,
+                max_gas_fee_per_gas: None,
+                max_priority_fee_per_gas: None,
+                rate_limit: None,
+            },
+            specific: super::policies::ether_transfer::Settings {
+                target: vec![RECIPIENT],
+                limit: VolumeRateLimit {
+                    max_volume: U256::from(100u64),
+                    window: Duration::hours(1),
+                },
+            },
+        };
+
+        let grant_id = engine
+            .create_grant::<EtherTransfer>(full_grant)
+            .await
+            .unwrap();
+
+        engine.revoke_grant(grant_id).await.unwrap();
+
+        let mut conn = db.get().await.unwrap();
+        diesel::update(evm_basic_grant::table)
+            .filter(evm_basic_grant::id.eq(grant_id))
+            .set(evm_basic_grant::revoked_at.eq::<Option<SqliteTimestamp>>(None))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+
+        let wallet_access = EvmWalletAccess {
+            id: WALLET_ACCESS_ID,
+            wallet_id: EvmWalletId::from_raw(10),
+            client_id: 20,
+            created_at: SqliteTimestamp(Utc::now()),
+        };
+        let context = EvalContext {
+            target: wallet_access,
+            chain: CHAIN_ID,
+            to: RECIPIENT,
+            value: U256::ONE,
+            calldata: Bytes::new(),
+            max_fee_per_gas: 1,
+            max_priority_fee_per_gas: 1,
+        };
+
+        let grant = EtherTransfer::try_find_grant(
+            &context, &mut conn,
+        )
+        .await
+        .unwrap()
+        .unwrap();
+
+        let result =
+            integrity::verify_entity(&mut conn, &vault, &grant.settings, grant.id).await;
+
+        assert!(matches!(
+            result,
+            Err(integrity::Error::MacMismatch { .. })
+        ));
+    }
+
+    #[test]
+    fn shared_settings_hash_changes_when_revoked_at_changes() {
+        use arbiter_crypto::hashing::Hashable;
+        use sha2::Digest;
+
+        let active = shared_settings();
+        let revoked = SharedGrantSettings {
+            revoked_at: Some(Utc::now()),
+            ..shared_settings()
+        };
+
+        let mut active_hash = sha2::Sha256::new();
+        active.hash(&mut active_hash);
+
+        let mut revoked_hash = sha2::Sha256::new();
+        revoked.hash(&mut revoked_hash);
+
+        assert_ne!(active_hash.finalize(), revoked_hash.finalize());
+    }
+}

server/crates/arbiter-server/src/evm/policies.rs

@@ -1,4 +1,8 @@
-use std::fmt::Display;
+use crate::{
+    crypto::integrity::v1::Integrable,
+    db::models::{EvmBasicGrant, EvmWalletAccess},
+    evm::utils,
+};
 
 use alloy::primitives::{Address, Bytes, ChainId, U256};
 use chrono::{DateTime, Duration, Utc};
@@ -6,14 +10,9 @@ use diesel::{
     ExpressionMethods as _, QueryDsl, SelectableHelper, result::QueryResult, sqlite::Sqlite,
 };
 use diesel_async::{AsyncConnection, RunQueryDsl};
-
+use std::fmt::Display;
 use thiserror::Error;
 
-use crate::{
-    db::models::{self, EvmBasicGrant, EvmWalletAccess},
-    evm::utils,
-};
-
 pub mod ether_transfer;
 pub mod token_transfers;
 
@@ -55,6 +54,9 @@ pub enum EvalViolation {
 
     #[error("Transaction type is not allowed by this grant")]
     InvalidTransactionType,
+
+    #[error("Mismatching chain ID")]
+    MismatchingChainId { expected: ChainId, actual: ChainId },
 }
 
 pub type DatabaseID = i32;
@@ -62,13 +64,12 @@ pub type DatabaseID = i32;
 #[derive(Debug)]
 pub struct Grant<PolicySettings> {
     pub id: DatabaseID,
-    pub shared_grant_id: DatabaseID, // ID of the basic grant for shared-logic checks like rate limits and validity periods
+    pub common_settings_id: DatabaseID, // ID of the basic grant for shared-logic checks like rate limits and validity periods
-    pub shared: SharedGrantSettings,
+    pub settings: CombinedSettings<PolicySettings>,
-    pub settings: PolicySettings,
 }
 
 pub trait Policy: Sized {
-    type Settings: Send + Sync + 'static + Into<SpecificGrant>;
+    type Settings: Send + Sync + 'static + Into<SpecificGrant> + Integrable;
     type Meaning: Display + std::fmt::Debug + Send + Sync + 'static + Into<SpecificMeaning>;
 
     fn analyze(context: &EvalContext) -> Option<Self::Meaning>;
@@ -84,10 +85,10 @@ pub trait Policy: Sized {
 
     // Create a new grant in the database based on the provided grant details, and return its ID
     fn create_grant(
-        basic: &models::EvmBasicGrant,
+        basic: &EvmBasicGrant,
         grant: &Self::Settings,
         conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    ) -> impl std::future::Future<Output = QueryResult<DatabaseID>> + Send;
+    ) -> impl Future<Output = QueryResult<DatabaseID>> + Send;
 
     // Try to find an existing grant that matches the transaction context, and return its details if found
     // Additionally, return ID of basic grant for shared-logic checks like rate limits and validity periods
@@ -124,25 +125,26 @@ pub enum SpecificMeaning {
     TokenTransfer(token_transfers::Meaning),
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, arbiter_macros::Hashable)]
 pub struct TransactionRateLimit {
     pub count: u32,
     pub window: Duration,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, arbiter_macros::Hashable)]
 pub struct VolumeRateLimit {
     pub max_volume: U256,
     pub window: Duration,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash, arbiter_macros::Hashable)]
 pub struct SharedGrantSettings {
     pub wallet_access_id: i32,
     pub chain: ChainId,
 
     pub valid_from: Option<DateTime<Utc>>,
     pub valid_until: Option<DateTime<Utc>>,
+    pub revoked_at: Option<DateTime<Utc>>,
 
     pub max_gas_fee_per_gas: Option<U256>,
     pub max_priority_fee_per_gas: Option<U256>,
@@ -151,12 +153,13 @@ pub struct SharedGrantSettings {
 }
 
 impl SharedGrantSettings {
-    fn try_from_model(model: EvmBasicGrant) -> QueryResult<Self> {
+    pub(crate) fn try_from_model(model: EvmBasicGrant) -> QueryResult<Self> {
         Ok(Self {
             wallet_access_id: model.wallet_access_id,
-            chain: model.chain_id as u64, // safe because chain_id is stored as i32 but is guaranteed to be a valid ChainId by the API when creating grants
+            chain: model.chain_id.into(),
             valid_from: model.valid_from.map(Into::into),
             valid_until: model.valid_until.map(Into::into),
+            revoked_at: model.revoked_at.map(Into::into),
             max_gas_fee_per_gas: model
                 .max_gas_fee_per_gas
                 .map(|b| utils::try_bytes_to_u256(&b))
@@ -165,10 +168,11 @@ impl SharedGrantSettings {
                 .max_priority_fee_per_gas
                 .map(|b| utils::try_bytes_to_u256(&b))
                 .transpose()?,
+            #[expect(clippy::cast_sign_loss, clippy::as_conversions, reason = "fixme! #86")]
             rate_limit: match (model.rate_limit_count, model.rate_limit_window_secs) {
                 (Some(count), Some(window_secs)) => Some(TransactionRateLimit {
                     count: count as u32,
-                    window: Duration::seconds(window_secs as i64),
+                    window: Duration::seconds(window_secs.into()),
                 }),
                 _ => None,
             },
@@ -178,7 +182,7 @@ impl SharedGrantSettings {
     pub async fn query_by_id(
         conn: &mut impl AsyncConnection<Backend = Sqlite>,
         id: i32,
-    ) -> diesel::result::QueryResult<Self> {
+    ) -> QueryResult<Self> {
         use crate::db::schema::evm_basic_grant;
 
         let basic_grant: EvmBasicGrant = evm_basic_grant::table
@@ -197,7 +201,22 @@ pub enum SpecificGrant {
     TokenTransfer(token_transfers::Settings),
 }
 
-pub struct FullGrant<PolicyGrant> {
+#[derive(Debug, arbiter_macros::Hashable)]
-    pub basic: SharedGrantSettings,
+pub struct CombinedSettings<PolicyGrant> {
+    pub shared: SharedGrantSettings,
     pub specific: PolicyGrant,
 }
+
+impl<P> CombinedSettings<P> {
+    pub fn generalize<Y: From<P>>(self) -> CombinedSettings<Y> {
+        CombinedSettings {
+            shared: self.shared,
+            specific: self.specific.into(),
+        }
+    }
+}
+
+impl<P: Integrable> Integrable for CombinedSettings<P> {
+    const KIND: &'static str = P::KIND;
+    const VERSION: i32 = P::VERSION;
+}

server/crates/arbiter-server/src/evm/policies/ether_transfer/mod.rs

@@ -1,29 +1,32 @@
-use std::collections::HashMap;
+use super::{DatabaseID, EvalContext, EvalViolation};
-use std::fmt::Display;
-
-use alloy::primitives::{Address, U256};
-use chrono::{DateTime, Duration, Utc};
-use diesel::dsl::{auto_type, insert_into};
-use diesel::sqlite::Sqlite;
-use diesel::{ExpressionMethods, JoinOnDsl, prelude::*};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-
-use crate::db::models::{
-    EvmBasicGrant, EvmEtherTransferGrant, EvmEtherTransferGrantTarget, EvmEtherTransferLimit,
-    NewEvmEtherTransferLimit, SqliteTimestamp,
-};
-use crate::db::schema::{evm_basic_grant, evm_ether_transfer_limit, evm_transaction_log};
-use crate::evm::policies::{
-    Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning, VolumeRateLimit,
-};
 use crate::{
+    crypto::integrity::v1::Integrable,
+    db::models::{
+        EvmBasicGrant, EvmEtherTransferGrant, EvmEtherTransferGrantTarget, EvmEtherTransferLimit,
+        NewEvmEtherTransferLimit, SqliteTimestamp,
+    },
+    db::schema::{evm_basic_grant, evm_ether_transfer_limit, evm_transaction_log},
     db::{
-        models::{self, NewEvmEtherTransferGrant, NewEvmEtherTransferGrantTarget},
+        models::{NewEvmEtherTransferGrant, NewEvmEtherTransferGrantTarget},
         schema::{evm_ether_transfer_grant, evm_ether_transfer_grant_target},
     },
+    evm::policies::{
+        CombinedSettings, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
+        VolumeRateLimit,
+    },
     evm::{policies::Policy, utils},
 };
 
+use alloy::primitives::{Address, U256};
+use chrono::{DateTime, Duration, Utc};
+use diesel::{
+    dsl::{auto_type, insert_into},
+    prelude::*,
+    sqlite::Sqlite,
+};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use std::{collections::HashMap, fmt::Display};
+
 #[auto_type]
 fn grant_join() -> _ {
     evm_ether_transfer_grant::table.inner_join(
@@ -31,8 +34,6 @@ fn grant_join() -> _ {
     )
 }
 
-use super::{DatabaseID, EvalContext, EvalViolation};
-
 // Plain ether transfer
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Meaning {
@@ -45,21 +46,24 @@ impl Display for Meaning {
     }
 }
 impl From<Meaning> for SpecificMeaning {
-    fn from(val: Meaning) -> SpecificMeaning {
+    fn from(val: Meaning) -> Self {
-        SpecificMeaning::EtherTransfer(val)
+        Self::EtherTransfer(val)
     }
 }
 
 // A grant for ether transfers, which can be scoped to specific target addresses and volume limits
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, arbiter_macros::Hashable)]
 pub struct Settings {
     pub target: Vec<Address>,
     pub limit: VolumeRateLimit,
 }
+impl Integrable for Settings {
+    const KIND: &'static str = "EtherTransfer";
+}
 
 impl From<Settings> for SpecificGrant {
-    fn from(val: Settings) -> SpecificGrant {
+    fn from(val: Settings) -> Self {
-        SpecificGrant::EtherTransfer(val)
+        Self::EtherTransfer(val)
     }
 }
 
@@ -70,9 +74,7 @@ async fn query_relevant_past_transaction(
 ) -> QueryResult<Vec<(U256, DateTime<Utc>)>> {
     let past_transactions: Vec<(Vec<u8>, SqliteTimestamp)> = evm_transaction_log::table
         .filter(evm_transaction_log::grant_id.eq(grant_id))
-        .filter(
+        .filter(evm_transaction_log::signed_at.ge(SqliteTimestamp(Utc::now() - longest_window)))
-            evm_transaction_log::signed_at.ge(SqliteTimestamp(chrono::Utc::now() - longest_window)),
-        )
         .select((
             evm_transaction_log::eth_value,
             evm_transaction_log::signed_at,
@@ -95,17 +97,17 @@ async fn check_rate_limits(
     db: &mut impl AsyncConnection<Backend = Sqlite>,
 ) -> QueryResult<Vec<EvalViolation>> {
     let mut violations = Vec::new();
-    let window = grant.settings.limit.window;
+    let window = grant.settings.specific.limit.window;
 
     let past_transaction = query_relevant_past_transaction(grant.id, window, db).await?;
 
-    let window_start = chrono::Utc::now() - grant.settings.limit.window;
+    let window_start = Utc::now() - grant.settings.specific.limit.window;
     let prospective_cumulative_volume: U256 = past_transaction
         .iter()
         .filter(|(_, timestamp)| timestamp >= &window_start)
         .fold(current_transfer_value, |acc, (value, _)| acc + *value);
 
-    if prospective_cumulative_volume > grant.settings.limit.max_volume {
+    if prospective_cumulative_volume > grant.settings.specific.limit.max_volume {
         violations.push(EvalViolation::VolumetricLimitExceeded);
     }
 
@@ -138,7 +140,7 @@ impl Policy for EtherTransfer {
         let mut violations = Vec::new();
 
         // Check if the target address is within the grant's allowed targets
-        if !grant.settings.target.contains(&meaning.to) {
+        if !grant.settings.specific.target.contains(&meaning.to) {
             violations.push(EvalViolation::InvalidTarget { target: meaning.to });
         }
 
@@ -149,10 +151,15 @@ impl Policy for EtherTransfer {
     }
 
     async fn create_grant(
-        basic: &models::EvmBasicGrant,
+        basic: &EvmBasicGrant,
         grant: &Self::Settings,
         conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    ) -> diesel::result::QueryResult<DatabaseID> {
+    ) -> QueryResult<DatabaseID> {
+        #[expect(
+            clippy::cast_possible_truncation,
+            clippy::as_conversions,
+            reason = "fixme! #86"
+        )]
         let limit_id: i32 = insert_into(evm_ether_transfer_limit::table)
             .values(NewEvmEtherTransferLimit {
                 window_secs: grant.limit.window.num_seconds() as i32,
@@ -187,7 +194,7 @@ impl Policy for EtherTransfer {
     async fn try_find_grant(
         context: &EvalContext,
         conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    ) -> diesel::result::QueryResult<Option<Grant<Self::Settings>>> {
+    ) -> QueryResult<Option<Grant<Self::Settings>>> {
         let target_bytes = context.to.to_vec();
 
         // Find a grant where:
@@ -241,15 +248,17 @@ impl Policy for EtherTransfer {
             limit: VolumeRateLimit {
                 max_volume: utils::try_bytes_to_u256(&limit.max_volume)
                     .map_err(|err| diesel::result::Error::DeserializationError(Box::new(err)))?,
-                window: chrono::Duration::seconds(limit.window_secs as i64),
+                window: Duration::seconds(limit.window_secs.into()),
             },
         };
 
         Ok(Some(Grant {
             id: grant.id,
-            shared_grant_id: grant.basic_grant_id,
+            common_settings_id: grant.basic_grant_id,
-            shared: SharedGrantSettings::try_from_model(basic_grant)?,
+            settings: CombinedSettings {
-            settings,
+                shared: SharedGrantSettings::try_from_model(basic_grant)?,
+                specific: settings,
+            },
         }))
     }
 
@@ -259,7 +268,7 @@ impl Policy for EtherTransfer {
         _log_id: i32,
         _grant: &Grant<Self::Settings>,
         _conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    ) -> diesel::result::QueryResult<()> {
+    ) -> QueryResult<()> {
         // Basic log is sufficient
 
         Ok(())
@@ -312,7 +321,7 @@ impl Policy for EtherTransfer {
             .map(|(basic, specific)| {
                 let targets: Vec<Address> = targets_by_grant
                     .get(&specific.id)
-                    .map(|v| v.as_slice())
+                    .map(Vec::as_slice)
                     .unwrap_or_default()
                     .iter()
                     .filter_map(|t| {
@@ -327,15 +336,17 @@ impl Policy for EtherTransfer {
 
                 Ok(Grant {
                     id: specific.id,
-                    shared_grant_id: specific.basic_grant_id,
+                    common_settings_id: specific.basic_grant_id,
-                    shared: SharedGrantSettings::try_from_model(basic)?,
+                    settings: CombinedSettings {
-                    settings: Settings {
+                        shared: SharedGrantSettings::try_from_model(basic)?,
-                        target: targets,
+                        specific: Settings {
-                        limit: VolumeRateLimit {
+                            target: targets,
-                            max_volume: utils::try_bytes_to_u256(&limit.max_volume).map_err(
+                            limit: VolumeRateLimit {
-                                |e| diesel::result::Error::DeserializationError(Box::new(e)),
+                                max_volume: utils::try_bytes_to_u256(&limit.max_volume).map_err(
-                            )?,
+                                    |e| diesel::result::Error::DeserializationError(Box::new(e)),
-                            window: Duration::seconds(limit.window_secs as i64),
+                                )?,
+                                window: Duration::seconds(limit.window_secs.into()),
+                            },
                         },
                     },
                 })

server/crates/arbiter-server/src/evm/policies/ether_transfer/tests.rs

@@ -1,24 +1,29 @@
+use super::{EtherTransfer, Settings};
+use crate::{
+    db::{
+        self, DatabaseConnection,
+        models::{
+            EvmBasicGrant, EvmWalletAccess, EvmWalletId, NewEvmBasicGrant, NewEvmTransactionLog,
+            SqliteTimestamp,
+        },
+        schema::{evm_basic_grant, evm_transaction_log},
+    },
+    evm::{
+        policies::{
+            CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
+            VolumeRateLimit,
+        },
+        utils,
+    },
+};
+
 use alloy::primitives::{Address, Bytes, U256, address};
 use chrono::{Duration, Utc};
 use diesel::{SelectableHelper, insert_into};
 use diesel_async::RunQueryDsl;
 
-use crate::db::{
-    self, DatabaseConnection,
-    models::{
-        EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, NewEvmTransactionLog, SqliteTimestamp,
-    },
-    schema::{evm_basic_grant, evm_transaction_log},
-};
-use crate::evm::{
-    policies::{EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings, VolumeRateLimit},
-    utils,
-};
-
-use super::{EtherTransfer, Settings};
-
 const WALLET_ACCESS_ID: i32 = 1;
-const CHAIN_ID: u64 = 1;
+const CHAIN_ID: alloy::primitives::ChainId = 1;
 
 const ALLOWED: Address = address!("1111111111111111111111111111111111111111");
 const OTHER: Address = address!("2222222222222222222222222222222222222222");
@@ -27,7 +32,7 @@ fn ctx(to: Address, value: U256) -> EvalContext {
     EvalContext {
         target: EvmWalletAccess {
             id: WALLET_ACCESS_ID,
-            wallet_id: 10,
+            wallet_id: EvmWalletId::from_raw(10),
             client_id: 20,
             created_at: SqliteTimestamp(Utc::now()),
         },
@@ -44,7 +49,7 @@ async fn insert_basic(conn: &mut DatabaseConnection, revoked: bool) -> EvmBasicG
     insert_into(evm_basic_grant::table)
         .values(NewEvmBasicGrant {
             wallet_access_id: WALLET_ACCESS_ID,
-            chain_id: CHAIN_ID as i32,
+            chain_id: CHAIN_ID.into(),
             valid_from: None,
             valid_until: None,
             max_gas_fee_per_gas: None,
@@ -75,14 +80,13 @@ fn shared() -> SharedGrantSettings {
         chain: CHAIN_ID,
         valid_from: None,
         valid_until: None,
+        revoked_at: None,
         max_gas_fee_per_gas: None,
         max_priority_fee_per_gas: None,
         rate_limit: None,
     }
 }
 
-// ── analyze ─────────────────────────────────────────────────────────────
-
 #[test]
 fn analyze_matches_empty_calldata() {
     let m = EtherTransfer::analyze(&ctx(ALLOWED, U256::from(1_000u64))).unwrap();
@@ -99,8 +103,6 @@ fn analyze_rejects_nonempty_calldata() {
     assert!(EtherTransfer::analyze(&context).is_none());
 }
 
-// ── evaluate ────────────────────────────────────────────────────────────
-
 #[tokio::test]
 async fn evaluate_passes_for_allowed_target() {
     let db = db::create_test_pool().await;
@@ -108,9 +110,11 @@ async fn evaluate_passes_for_allowed_target() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
+        common_settings_id: 999,
-        shared: shared(),
+        settings: CombinedSettings {
-        settings: make_settings(vec![ALLOWED], 1_000_000),
+            shared: shared(),
+            specific: make_settings(vec![ALLOWED], 1_000_000),
+        },
     };
     let context = ctx(ALLOWED, U256::from(100u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -127,9 +131,11 @@ async fn evaluate_rejects_disallowed_target() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
+        common_settings_id: 999,
-        shared: shared(),
+        settings: CombinedSettings {
-        settings: make_settings(vec![ALLOWED], 1_000_000),
+            shared: shared(),
+            specific: make_settings(vec![ALLOWED], 1_000_000),
+        },
     };
     let context = ctx(OTHER, U256::from(100u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -157,7 +163,7 @@ async fn evaluate_passes_when_volume_within_limit() {
         .values(NewEvmTransactionLog {
             grant_id,
             wallet_access_id: WALLET_ACCESS_ID,
-            chain_id: CHAIN_ID as i32,
+            chain_id: CHAIN_ID.into(),
             eth_value: utils::u256_to_bytes(U256::from(500u64)).to_vec(),
             signed_at: SqliteTimestamp(Utc::now()),
         })
@@ -167,9 +173,11 @@ async fn evaluate_passes_when_volume_within_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
+        common_settings_id: basic.id,
-        shared: shared(),
+        settings: CombinedSettings {
-        settings,
+            shared: shared(),
+            specific: settings,
+        },
     };
     let context = ctx(ALLOWED, U256::from(100u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -197,7 +205,7 @@ async fn evaluate_rejects_volume_over_limit() {
         .values(NewEvmTransactionLog {
             grant_id,
             wallet_access_id: WALLET_ACCESS_ID,
-            chain_id: CHAIN_ID as i32,
+            chain_id: CHAIN_ID.into(),
             eth_value: utils::u256_to_bytes(U256::from(1_000u64)).to_vec(),
             signed_at: SqliteTimestamp(Utc::now()),
         })
@@ -207,9 +215,11 @@ async fn evaluate_rejects_volume_over_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
+        common_settings_id: basic.id,
-        shared: shared(),
+        settings: CombinedSettings {
-        settings,
+            shared: shared(),
+            specific: settings,
+        },
     };
     let context = ctx(ALLOWED, U256::from(1u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -238,7 +248,7 @@ async fn evaluate_passes_at_exactly_volume_limit() {
         .values(NewEvmTransactionLog {
             grant_id,
             wallet_access_id: WALLET_ACCESS_ID,
-            chain_id: CHAIN_ID as i32,
+            chain_id: CHAIN_ID.into(),
             eth_value: utils::u256_to_bytes(U256::from(900u64)).to_vec(),
             signed_at: SqliteTimestamp(Utc::now()),
         })
@@ -248,9 +258,11 @@ async fn evaluate_passes_at_exactly_volume_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
+        common_settings_id: basic.id,
-        shared: shared(),
+        settings: CombinedSettings {
-        settings,
+            shared: shared(),
+            specific: settings,
+        },
     };
     let context = ctx(ALLOWED, U256::from(100u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -263,8 +275,6 @@ async fn evaluate_passes_at_exactly_volume_limit() {
     );
 }
 
-// ── try_find_grant ───────────────────────────────────────────────────────
-
 #[tokio::test]
 async fn try_find_grant_roundtrip() {
     let db = db::create_test_pool().await;
@@ -282,8 +292,11 @@ async fn try_find_grant_roundtrip() {
 
     assert!(found.is_some());
     let g = found.unwrap();
-    assert_eq!(g.settings.target, vec![ALLOWED]);
+    assert_eq!(g.settings.specific.target, vec![ALLOWED]);
-    assert_eq!(g.settings.limit.max_volume, U256::from(1_000_000u64));
+    assert_eq!(
+        g.settings.specific.limit.max_volume,
+        U256::from(1_000_000u64)
+    );
 }
 
 #[tokio::test]
@@ -320,7 +333,36 @@ async fn try_find_grant_wrong_target_returns_none() {
     assert!(found.is_none());
 }
 
-// ── find_all_grants ──────────────────────────────────────────────────────
+proptest::proptest! {
+    #[test]
+    fn target_order_does_not_affect_hash(
+        raw_addrs in proptest::collection::vec(proptest::prelude::any::<[u8; 20]>(), 0..8),
+        seed in proptest::prelude::any::<u64>(),
+        max_volume in proptest::prelude::any::<u64>(),
+        window_secs in 1i64..=86400,
+    ) {
+        use rand::{SeedableRng, seq::SliceRandom};
+        use sha2::Digest;
+        use arbiter_crypto::hashing::Hashable;
+
+        let addrs: Vec<Address> = raw_addrs.iter().map(|b| Address::from(*b)).collect();
+        let mut shuffled = addrs.clone();
+        shuffled.shuffle(&mut rand::rngs::StdRng::seed_from_u64(seed));
+
+        let limit = VolumeRateLimit {
+            max_volume: U256::from(max_volume),
+            window: Duration::seconds(window_secs),
+        };
+
+        let mut h1 = sha2::Sha256::new();
+        Settings { target: addrs, limit: limit.clone() }.hash(&mut h1);
+
+        let mut h2 = sha2::Sha256::new();
+        Settings { target: shuffled, limit }.hash(&mut h2);
+
+        proptest::prop_assert_eq!(h1.finalize(), h2.finalize());
+    }
+}
 
 #[tokio::test]
 async fn find_all_grants_empty_db() {
@@ -347,7 +389,7 @@ async fn find_all_grants_excludes_revoked() {
 
     let all = EtherTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 1);
-    assert_eq!(all[0].settings.target, vec![ALLOWED]);
+    assert_eq!(all[0].settings.specific.target, vec![ALLOWED]);
 }
 
 #[tokio::test]
@@ -363,8 +405,11 @@ async fn find_all_grants_multiple_targets() {
 
     let all = EtherTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 1);
-    assert_eq!(all[0].settings.target.len(), 2);
+    assert_eq!(all[0].settings.specific.target.len(), 2);
-    assert_eq!(all[0].settings.limit.max_volume, U256::from(1_000_000u64));
+    assert_eq!(
+        all[0].settings.specific.limit.max_volume,
+        U256::from(1_000_000u64)
+    );
 }
 
 #[tokio::test]

server/crates/arbiter-server/src/evm/policies/token_transfers/mod.rs

@@ -1,33 +1,38 @@
-use std::collections::HashMap;
+use super::{DatabaseID, EvalContext, EvalViolation};
+use crate::{
+    crypto::integrity::Integrable,
+    db::models::{
+        EvmBasicGrant, EvmTokenTransferGrant, EvmTokenTransferVolumeLimit,
+        NewEvmTokenTransferGrant, NewEvmTokenTransferLog, NewEvmTokenTransferVolumeLimit,
+        SqliteTimestamp,
+    },
+    db::schema::{
+        evm_basic_grant, evm_token_transfer_grant, evm_token_transfer_log,
+        evm_token_transfer_volume_limit,
+    },
+    evm::policies::CombinedSettings,
+    evm::{
+        abi::IERC20::transferCall,
+        policies::{
+            Grant, Policy, SharedGrantSettings, SpecificGrant, SpecificMeaning, VolumeRateLimit,
+        },
+        utils,
+    },
+};
+use arbiter_tokens_registry::evm::nonfungible::{self, TokenInfo};
 
 use alloy::{
     primitives::{Address, U256},
     sol_types::SolCall,
 };
-use arbiter_tokens_registry::evm::nonfungible::{self, TokenInfo};
 use chrono::{DateTime, Duration, Utc};
-use diesel::dsl::{auto_type, insert_into};
+use diesel::{
-use diesel::sqlite::Sqlite;
+    dsl::{auto_type, insert_into},
-use diesel::{ExpressionMethods, prelude::*};
+    prelude::*,
+    sqlite::Sqlite,
+};
 use diesel_async::{AsyncConnection, RunQueryDsl};
-
+use std::collections::HashMap;
-use crate::db::models::{
-    EvmBasicGrant, EvmTokenTransferGrant, EvmTokenTransferVolumeLimit, NewEvmTokenTransferGrant,
-    NewEvmTokenTransferLog, NewEvmTokenTransferVolumeLimit, SqliteTimestamp,
-};
-use crate::db::schema::{
-    evm_basic_grant, evm_token_transfer_grant, evm_token_transfer_log,
-    evm_token_transfer_volume_limit,
-};
-use crate::evm::{
-    abi::IERC20::transferCall,
-    policies::{
-        Grant, Policy, SharedGrantSettings, SpecificGrant, SpecificMeaning, VolumeRateLimit,
-    },
-    utils,
-};
-
-use super::{DatabaseID, EvalContext, EvalViolation};
 
 #[auto_type]
 fn grant_join() -> _ {
@@ -38,9 +43,9 @@ fn grant_join() -> _ {
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Meaning {
-    pub(crate) token: &'static TokenInfo,
+    pub token: &'static TokenInfo,
-    pub(crate) to: Address,
+    pub to: Address,
-    pub(crate) value: U256,
+    pub value: U256,
 }
 impl std::fmt::Display for Meaning {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -52,21 +57,25 @@ impl std::fmt::Display for Meaning {
     }
 }
 impl From<Meaning> for SpecificMeaning {
-    fn from(val: Meaning) -> SpecificMeaning {
+    fn from(val: Meaning) -> Self {
-        SpecificMeaning::TokenTransfer(val)
+        Self::TokenTransfer(val)
     }
 }
 
 // A grant for token transfers, which can be scoped to specific target addresses and volume limits
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, arbiter_macros::Hashable)]
 pub struct Settings {
     pub token_contract: Address,
     pub target: Option<Address>,
     pub volume_limits: Vec<VolumeRateLimit>,
 }
+impl Integrable for Settings {
+    const KIND: &'static str = "TokenTransfer";
+}
+
 impl From<Settings> for SpecificGrant {
-    fn from(val: Settings) -> SpecificGrant {
+    fn from(val: Settings) -> Self {
-        SpecificGrant::TokenTransfer(val)
+        Self::TokenTransfer(val)
     }
 }
 
@@ -77,10 +86,7 @@ async fn query_relevant_past_transfers(
 ) -> QueryResult<Vec<(U256, DateTime<Utc>)>> {
     let past_logs: Vec<(Vec<u8>, SqliteTimestamp)> = evm_token_transfer_log::table
         .filter(evm_token_transfer_log::grant_id.eq(grant_id))
-        .filter(
+        .filter(evm_token_transfer_log::created_at.ge(SqliteTimestamp(Utc::now() - longest_window)))
-            evm_token_transfer_log::created_at
-                .ge(SqliteTimestamp(chrono::Utc::now() - longest_window)),
-        )
         .select((
             evm_token_transfer_log::value,
             evm_token_transfer_log::created_at,
@@ -106,14 +112,21 @@ async fn check_volume_rate_limits(
 ) -> QueryResult<Vec<EvalViolation>> {
     let mut violations = Vec::new();
 
-    let Some(longest_window) = grant.settings.volume_limits.iter().map(|l| l.window).max() else {
+    let Some(longest_window) = grant
+        .settings
+        .specific
+        .volume_limits
+        .iter()
+        .map(|l| l.window)
+        .max()
+    else {
         return Ok(violations);
     };
 
     let past_transfers = query_relevant_past_transfers(grant.id, longest_window, db).await?;
 
-    for limit in &grant.settings.volume_limits {
+    for limit in &grant.settings.specific.volume_limits {
-        let window_start = chrono::Utc::now() - limit.window;
+        let window_start = Utc::now() - limit.window;
         let prospective_cumulative_volume: U256 = past_transfers
             .iter()
             .filter(|(_, timestamp)| timestamp >= &window_start)
@@ -158,7 +171,7 @@ impl Policy for TokenTransfer {
             return Ok(violations);
         }
 
-        if let Some(allowed) = grant.settings.target
+        if let Some(allowed) = grant.settings.specific.target
             && allowed != meaning.to
         {
             violations.push(EvalViolation::InvalidTarget { target: meaning.to });
@@ -189,6 +202,11 @@ impl Policy for TokenTransfer {
             .await?;
 
         for limit in &grant.volume_limits {
+            #[expect(
+                clippy::cast_possible_truncation,
+                clippy::as_conversions,
+                reason = "fixme! #86"
+            )]
             insert_into(evm_token_transfer_volume_limit::table)
                 .values(NewEvmTokenTransferVolumeLimit {
                     grant_id,
@@ -238,7 +256,7 @@ impl Policy for TokenTransfer {
                     max_volume: utils::try_bytes_to_u256(&row.max_volume).map_err(|err| {
                         diesel::result::Error::DeserializationError(Box::new(err))
                     })?,
-                    window: Duration::seconds(row.window_secs as i64),
+                    window: Duration::seconds(row.window_secs.into()),
                 })
             })
             .collect::<QueryResult<Vec<_>>>()?;
@@ -269,9 +287,11 @@ impl Policy for TokenTransfer {
 
         Ok(Some(Grant {
             id: token_grant.id,
-            shared_grant_id: token_grant.basic_grant_id,
+            common_settings_id: token_grant.basic_grant_id,
-            shared: SharedGrantSettings::try_from_model(basic_grant)?,
+            settings: CombinedSettings {
-            settings,
+                shared: SharedGrantSettings::try_from_model(basic_grant)?,
+                specific: settings,
+            },
         }))
     }
 
@@ -286,7 +306,7 @@ impl Policy for TokenTransfer {
             .values(NewEvmTokenTransferLog {
                 grant_id: grant.id,
                 log_id,
-                chain_id: context.chain as i32,
+                chain_id: context.chain.into(),
                 token_contract: context.to.to_vec(),
                 recipient_address: meaning.to.to_vec(),
                 value: utils::u256_to_bytes(meaning.value).to_vec(),
@@ -335,7 +355,7 @@ impl Policy for TokenTransfer {
             .map(|(basic, specific)| {
                 let volume_limits: Vec<VolumeRateLimit> = limits_by_grant
                     .get(&specific.id)
-                    .map(|v| v.as_slice())
+                    .map(Vec::as_slice)
                     .unwrap_or_default()
                     .iter()
                     .map(|row| {
@@ -343,7 +363,7 @@ impl Policy for TokenTransfer {
                             max_volume: utils::try_bytes_to_u256(&row.max_volume).map_err(|e| {
                                 diesel::result::Error::DeserializationError(Box::new(e))
                             })?,
-                            window: Duration::seconds(row.window_secs as i64),
+                            window: Duration::seconds(row.window_secs.into()),
                         })
                     })
                     .collect::<QueryResult<Vec<_>>>()?;
@@ -369,12 +389,14 @@ impl Policy for TokenTransfer {
 
                 Ok(Grant {
                     id: specific.id,
-                    shared_grant_id: specific.basic_grant_id,
+                    common_settings_id: specific.basic_grant_id,
-                    shared: SharedGrantSettings::try_from_model(basic)?,
+                    settings: CombinedSettings {
-                    settings: Settings {
+                        shared: SharedGrantSettings::try_from_model(basic)?,
-                        token_contract: Address::from(token_contract),
+                        specific: Settings {
-                        target,
+                            token_contract: Address::from(token_contract),
-                        volume_limits,
+                            target,
+                            volume_limits,
+                        },
                     },
                 })
             })

server/crates/arbiter-server/src/evm/policies/token_transfers/tests.rs

@@ -1,22 +1,28 @@
-use alloy::primitives::{Address, Bytes, U256, address};
+use super::{Settings, TokenTransfer};
-use alloy::sol_types::SolCall;
+use crate::{
+    db::{
+        self, DatabaseConnection,
+        models::{EvmBasicGrant, EvmWalletAccess, EvmWalletId, NewEvmBasicGrant, SqliteTimestamp},
+        schema::evm_basic_grant,
+    },
+    evm::{
+        abi::IERC20::transferCall,
+        policies::{
+            CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
+            VolumeRateLimit,
+        },
+        utils,
+    },
+};
+
+use alloy::{
+    primitives::{Address, Bytes, U256, address},
+    sol_types::SolCall,
+};
 use chrono::{Duration, Utc};
 use diesel::{SelectableHelper, insert_into};
 use diesel_async::RunQueryDsl;
 
-use crate::db::{
-    self, DatabaseConnection,
-    models::{EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, SqliteTimestamp},
-    schema::evm_basic_grant,
-};
-use crate::evm::{
-    abi::IERC20::transferCall,
-    policies::{EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings, VolumeRateLimit},
-    utils,
-};
-
-use super::{Settings, TokenTransfer};
-
 // DAI on Ethereum mainnet — present in the static token registry
 const CHAIN_ID: u64 = 1;
 const DAI: Address = address!("6B175474E89094C44Da98b954EedeAC495271d0F");
@@ -39,7 +45,7 @@ fn ctx(to: Address, calldata: Bytes) -> EvalContext {
     EvalContext {
         target: EvmWalletAccess {
             id: WALLET_ACCESS_ID,
-            wallet_id: 10,
+            wallet_id: EvmWalletId::from_raw(10),
             client_id: 20,
             created_at: SqliteTimestamp(Utc::now()),
         },
@@ -56,7 +62,7 @@ async fn insert_basic(conn: &mut DatabaseConnection, revoked: bool) -> EvmBasicG
     insert_into(evm_basic_grant::table)
         .values(NewEvmBasicGrant {
             wallet_access_id: WALLET_ACCESS_ID,
-            chain_id: CHAIN_ID as i32,
+            chain_id: CHAIN_ID.into(),
             valid_from: None,
             valid_until: None,
             max_gas_fee_per_gas: None,
@@ -92,14 +98,13 @@ fn shared() -> SharedGrantSettings {
         chain: CHAIN_ID,
         valid_from: None,
         valid_until: None,
+        revoked_at: None,
         max_gas_fee_per_gas: None,
         max_priority_fee_per_gas: None,
         rate_limit: None,
     }
 }
 
-// ── analyze ─────────────────────────────────────────────────────────────
-
 #[test]
 fn analyze_known_token_valid_calldata() {
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
@@ -125,8 +130,6 @@ fn analyze_empty_calldata_returns_none() {
     assert!(TokenTransfer::analyze(&ctx(DAI, Bytes::new())).is_none());
 }
 
-// ── evaluate ────────────────────────────────────────────────────────────
-
 #[tokio::test]
 async fn evaluate_rejects_nonzero_eth_value() {
     let db = db::create_test_pool().await;
@@ -134,9 +137,11 @@ async fn evaluate_rejects_nonzero_eth_value() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
+        common_settings_id: 999,
-        shared: shared(),
+        settings: CombinedSettings {
-        settings: make_settings(None, None),
+            shared: shared(),
+            specific: make_settings(None, None),
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let mut context = ctx(DAI, calldata);
@@ -163,9 +168,11 @@ async fn evaluate_passes_any_recipient_when_no_restriction() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
+        common_settings_id: 999,
-        shared: shared(),
+        settings: CombinedSettings {
-        settings: make_settings(None, None),
+            shared: shared(),
+            specific: make_settings(None, None),
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
@@ -183,9 +190,11 @@ async fn evaluate_passes_matching_restricted_recipient() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
+        common_settings_id: 999,
-        shared: shared(),
+        settings: CombinedSettings {
-        settings: make_settings(Some(RECIPIENT), None),
+            shared: shared(),
+            specific: make_settings(Some(RECIPIENT), None),
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
@@ -203,9 +212,11 @@ async fn evaluate_rejects_wrong_restricted_recipient() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
+        common_settings_id: 999,
-        shared: shared(),
+        settings: CombinedSettings {
-        settings: make_settings(Some(RECIPIENT), None),
+            shared: shared(),
+            specific: make_settings(Some(RECIPIENT), None),
+        },
     };
     let calldata = transfer_calldata(OTHER, U256::from(100u64));
     let context = ctx(DAI, calldata);
@@ -231,12 +242,11 @@ async fn evaluate_passes_volume_at_exact_limit() {
         .unwrap();
 
     // Record a past transfer of 900, with current transfer 100 => exactly 1000 limit
-    use crate::db::{models::NewEvmTokenTransferLog, schema::evm_token_transfer_log};
+    insert_into(db::schema::evm_token_transfer_log::table)
-    insert_into(evm_token_transfer_log::table)
+        .values(db::models::NewEvmTokenTransferLog {
-        .values(NewEvmTokenTransferLog {
             grant_id,
             log_id: 0,
-            chain_id: CHAIN_ID as i32,
+            chain_id: CHAIN_ID.into(),
             token_contract: DAI.to_vec(),
             recipient_address: RECIPIENT.to_vec(),
             value: utils::u256_to_bytes(U256::from(900u64)).to_vec(),
@@ -247,9 +257,11 @@ async fn evaluate_passes_volume_at_exact_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
+        common_settings_id: basic.id,
-        shared: shared(),
+        settings: CombinedSettings {
-        settings,
+            shared: shared(),
+            specific: settings,
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
@@ -274,12 +286,11 @@ async fn evaluate_rejects_volume_over_limit() {
         .await
         .unwrap();
 
-    use crate::db::{models::NewEvmTokenTransferLog, schema::evm_token_transfer_log};
+    insert_into(db::schema::evm_token_transfer_log::table)
-    insert_into(evm_token_transfer_log::table)
+        .values(db::models::NewEvmTokenTransferLog {
-        .values(NewEvmTokenTransferLog {
             grant_id,
             log_id: 0,
-            chain_id: CHAIN_ID as i32,
+            chain_id: CHAIN_ID.into(),
             token_contract: DAI.to_vec(),
             recipient_address: RECIPIENT.to_vec(),
             value: utils::u256_to_bytes(U256::from(1_000u64)).to_vec(),
@@ -290,9 +301,11 @@ async fn evaluate_rejects_volume_over_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
+        common_settings_id: basic.id,
-        shared: shared(),
+        settings: CombinedSettings {
-        settings,
+            shared: shared(),
+            specific: settings,
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(1u64));
     let context = ctx(DAI, calldata);
@@ -313,9 +326,11 @@ async fn evaluate_no_volume_limits_always_passes() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
+        common_settings_id: 999,
-        shared: shared(),
+        settings: CombinedSettings {
-        settings: make_settings(None, None), // no volume limits
+            shared: shared(),
+            specific: make_settings(None, None), // no volume limits
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(u64::MAX));
     let context = ctx(DAI, calldata);
@@ -349,10 +364,13 @@ async fn try_find_grant_roundtrip() {
 
     assert!(found.is_some());
     let g = found.unwrap();
-    assert_eq!(g.settings.token_contract, DAI);
+    assert_eq!(g.settings.specific.token_contract, DAI);
-    assert_eq!(g.settings.target, Some(RECIPIENT));
+    assert_eq!(g.settings.specific.target, Some(RECIPIENT));
-    assert_eq!(g.settings.volume_limits.len(), 1);
+    assert_eq!(g.settings.specific.volume_limits.len(), 1);
-    assert_eq!(g.settings.volume_limits[0].max_volume, U256::from(5_000u64));
+    assert_eq!(
+        g.settings.specific.volume_limits[0].max_volume,
+        U256::from(5_000u64)
+    );
 }
 
 #[tokio::test]
@@ -392,7 +410,39 @@ async fn try_find_grant_unknown_token_returns_none() {
     assert!(found.is_none());
 }
 
-// ── find_all_grants ──────────────────────────────────────────────────────
+proptest::proptest! {
+    #[test]
+    fn volume_limits_order_does_not_affect_hash(
+        raw_limits in proptest::collection::vec(
+            (proptest::prelude::any::<u64>(), 1i64..=86400),
+            0..8,
+        ),
+        seed in proptest::prelude::any::<u64>(),
+    ) {
+        use rand::{SeedableRng, seq::SliceRandom};
+        use sha2::Digest;
+        use arbiter_crypto::hashing::Hashable;
+
+        let limits: Vec<VolumeRateLimit> = raw_limits
+            .iter()
+            .map(|(max_vol, window_secs)| VolumeRateLimit {
+                max_volume: U256::from(*max_vol),
+                window: Duration::seconds(*window_secs),
+            })
+            .collect();
+
+        let mut shuffled = limits.clone();
+        shuffled.shuffle(&mut rand::rngs::StdRng::seed_from_u64(seed));
+
+        let mut h1 = sha2::Sha256::new();
+        Settings { token_contract: DAI, target: None, volume_limits: limits }.hash(&mut h1);
+
+        let mut h2 = sha2::Sha256::new();
+        Settings { token_contract: DAI, target: None, volume_limits: shuffled }.hash(&mut h2);
+
+        proptest::prop_assert_eq!(h1.finalize(), h2.finalize());
+    }
+}
 
 #[tokio::test]
 async fn find_all_grants_empty_db() {
@@ -434,9 +484,9 @@ async fn find_all_grants_loads_volume_limits() {
 
     let all = TokenTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 1);
-    assert_eq!(all[0].settings.volume_limits.len(), 1);
+    assert_eq!(all[0].settings.specific.volume_limits.len(), 1);
     assert_eq!(
-        all[0].settings.volume_limits[0].max_volume,
+        all[0].settings.specific.volume_limits[0].max_volume,
         U256::from(9_999u64)
     );
 }

server/crates/arbiter-server/src/evm/safe_signer.rs

@@ -1,6 +1,5 @@
-use std::sync::Mutex;
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 
-use crate::safe_cell::{SafeCell, SafeCellHandle as _};
 use alloy::{
     consensus::SignableTransaction,
     network::{TxSigner, TxSignerSync},
@@ -9,6 +8,7 @@ use alloy::{
 };
 use async_trait::async_trait;
 use k256::ecdsa::{self, RecoveryId, SigningKey, signature::hazmat::PrehashSigner};
+use std::sync::Mutex;
 
 /// An Ethereum signer that stores its secp256k1 secret key inside a
 /// hardware-protected [`MemSafe`] cell.
@@ -82,8 +82,8 @@ impl SafeSigner {
         })
     }
 
+    #[expect(clippy::significant_drop_tightening, reason = "false positive")]
     fn sign_hash_inner(&self, hash: &B256) -> Result<Signature> {
-        #[allow(clippy::expect_used)]
         let mut cell = self.key.lock().expect("SafeSigner mutex poisoned");
         let reader = cell.read();
         let sig: (ecdsa::Signature, RecoveryId) = reader.sign_prehash(hash.as_ref())?;
@@ -96,7 +96,6 @@ impl SafeSigner {
         {
             return Err(Error::TransactionChainIdMismatch {
                 signer: chain_id,
-                #[allow(clippy::expect_used)]
                 tx: tx.chain_id().expect("Chain ID is guaranteed to be set"),
             });
         }