feat(macros): enhance Integrable derive with validation and versioning improvements

Reviewed-on: #83

.gitignore

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

.woodpecker/server-test.yaml

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

AGENTS.md

@@ -6,7 +6,7 @@ This file provides guidance to Codex (Codex.ai/code) when working with code in t
 
 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
+- **`operator/`** — Flutter desktop app (macOS/Windows) with a Rust backend via Rinf
 - **`protobufs/`** — Protocol Buffer definitions shared between server and client
 
 The vault never exposes key material; it only produces signatures when requests satisfy configured policies.
@@ -28,7 +28,7 @@ Key versions: Rust 1.93.0 (with clippy), Flutter 3.38.9-stable, protoc 29.6, die
 |---|---|
 | `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-operator` | Rust client library for the operator side of the gRPC protocol |
 | `arbiter-client` | Rust client library for SDK clients |
 
 ### Common Commands
@@ -66,11 +66,11 @@ cargo insta review
 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.
+- **`Vault`** — Holds the encrypted root key and manages the Sealed/Unsealed vault state machine. On unseal, decrypts the root key into a `memsafe` hardened memory cell.
-- **`FlowCoordinator`** — Coordinates cross-connection flow between user agents and SDK clients.
+- **`FlowCoordinator`** — Coordinates cross-connection flow between operators 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.
+Per-connection actors live under `actors/operator/` and `actors/client/`, each with `auth` (challenge-response authentication) and `session` (post-auth operations) sub-modules.
 
 **Database:** SQLite via `diesel-async` + `bb8` connection pool. Schema managed by embedded Diesel migrations in `crates/arbiter-server/migrations/`. DB file lives at `~/.arbiter/arbiter.sqlite`. Tests use a temp-file DB via `db::create_test_pool()`.
 
@@ -100,20 +100,41 @@ 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/`)
+### Code Conventions
 
-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.
+**`#[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:
 
-Communication between Dart and Rust uses typed **signals** defined in `useragent/native/hub/src/signals/`. After modifying signal structs, regenerate Dart bindings:
+- Methods that return `bool` indicating success/failure or validation state
+- Any function where ignoring the return value indicates a logic error
+
+Do not apply `#[must_use]` redundantly to items (types or functions) that are already annotated with `#[must_use]`.
+
+Example:
+
+```rust
+#[must_use]
+pub fn verify(&self, nonce: i32, context: &[u8], signature: &Signature) -> bool {
+    // verification logic
+}
+```
+
+This forces callers to either use the return value or explicitly ignore it with `let _ = ...;`, preventing silent failures.
+
+## Operator (Flutter + Rinf at `operator/`)
+
+The Flutter app uses [Rinf](https://rinf.cunarist.org) to call Rust code. The Rust logic lives in `operator/native/hub/` as a separate crate that uses `arbiter-operator` for the gRPC client.
+
+Communication between Dart and Rust uses typed **signals** defined in `operator/native/hub/src/signals/`. After modifying signal structs, regenerate Dart bindings:
 
 ```sh
-cd useragent && rinf gen
+cd operator && rinf gen
 ```
 
 ### Common Commands
 
 ```sh
-cd useragent
+cd operator
 
 # Run the app (macOS or Windows)
 flutter run
@@ -125,4 +146,4 @@ rinf gen
 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.
+The Rinf Rust entry point is `operator/native/hub/src/lib.rs`. It spawns actors defined in `operator/native/hub/src/actors/` which handle Dart↔server communication via signals.

ARCHITECTURE.md

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

CLAUDE.md

@@ -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
 

docs/ARCHITECTURE.md

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

docs/IMPLEMENTATION.md

@@ -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:
 
@@ -22,52 +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
-- **Signature scheme:** ed25519
+- **Client protocol:** ML-DSA
+
+### User-Agent Authentication
+
+Operator authentication supports multiple signature schemes because platform-provided "hardware-bound" keys do not expose a uniform algorithm across operating systems and hardware.
+
+- **Supported schemes:** ML-DSA
+- **Why:** Secure Enclave (MacOS) support them natively, on other platforms we could emulate while they roll-out
 
 ### Encryption at Rest
 - **Scheme:** Symmetric AEAD — currently **XChaCha20-Poly1305**
@@ -88,7 +86,7 @@ The `program_client.nonce` column stores the **next usable nonce** — i.e. it i
 
 ### 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
@@ -117,6 +115,52 @@ The central abstraction is the `Policy` trait. Each implementation handles one s
 4. **Evaluate** — `Policy::evaluate` checks the decoded meaning against the grant's policy-specific constraints and returns any violations.
 5. **Record** — If `RunKind::Execution` and there are no violations, the engine writes to `evm_transaction_log` and calls `Policy::record_transaction` for any policy-specific logging (e.g., token transfer volume).
 
+The detailed branch structure is shown below:
+
+```mermaid
+flowchart TD
+    A[SDK Client sends sign transaction request] --> B[Server resolves wallet]
+    B --> C{Wallet exists?}
+
+    C -- No --> Z1[Return wallet not found error]
+    C -- Yes --> D[Check SDK client wallet visibility]
+
+    D --> E{Wallet visible to SDK client?}
+    E -- No --> F[Start wallet visibility voting flow]
+    F --> G{Vote approved?}
+    G -- No --> Z2[Return wallet access denied error]
+    G -- Yes --> H[Persist wallet visibility]
+    E -- Yes --> I[Classify transaction meaning]
+    H --> I
+
+    I --> J{Meaning supported?}
+    J -- No --> Z3[Return unsupported transaction error]
+    J -- Yes --> K[Find matching grant]
+
+    K --> L{Grant exists?}
+    L -- Yes --> M[Check grant limits]
+    L -- No --> N[Start execution or grant voting flow]
+
+    N --> O{Operator decision}
+    O -- Reject --> Z4[Return no matching grant error]
+    O -- Allow once --> M
+    O -- Create grant --> P[Create grant with user-selected limits]
+    P --> Q[Persist grant]
+    Q --> M
+
+    M --> R{Limits exceeded?}
+    R -- Yes --> Z5[Return evaluation error]
+    R -- No --> S[Record transaction in logs]
+    S --> T[Produce signature]
+    T --> U[Return signature to SDK client]
+
+    note1[Limit checks include volume, count, and gas constraints.]
+    note2[Grant lookup depends on classified meaning, such as ether transfer or token transfer.]
+
+    K -. uses .-> note2
+    M -. checks .-> note1
+```
+
 ### Policy Trait
 
 | Method | Purpose |
@@ -148,7 +192,7 @@ The central abstraction is the `Policy` trait. Each implementation handles one s
 Every grant has two layers:
 
 - **Shared (`evm_basic_grant`)** — wallet, chain, validity period, gas fee caps, transaction count rate limit. One row per grant regardless of type.
-- **Specific** — policy-owned tables (`evm_ether_transfer_grant`, `evm_token_transfer_grant`, etc.) holding type-specific configuration.
+- **Specific** — policy-owned tables (`evm_ether_transfer_grant`, `evm_token_transfer_grant`) holding type-specific configuration.
 
 `find_all_grants` uses a `#[diesel::auto_type]` base join between the specific and shared tables, then batch-loads related rows (targets, volume limits) in two additional queries to avoid N+1.
 
@@ -171,7 +215,6 @@ These are checked centrally in `check_shared_constraints` before policy evaluati
 - **Only EIP-1559 transactions are supported.** Legacy and EIP-2930 types are rejected outright.
 - **No opaque-calldata (unknown contract) grant type.** The architecture describes a category for unrecognised contracts, but no policy implements it yet. Any transaction that is not a plain ETH transfer or a known ERC-20 transfer is unconditionally rejected.
 - **Token registry is static.** Tokens are recognised only if they appear in the hard-coded `arbiter_tokens_registry` crate. There is no mechanism to register additional contracts at runtime.
-- **Nonce management is not implemented.** The architecture lists nonce deduplication as a core responsibility, but no nonce tracking or enforcement exists yet.
 
 ---
 
@@ -179,5 +222,5 @@ These are checked centrally in `check_shared_constraints` before policy evaluati
 
 The unsealed root key must be held in a hardened memory cell resistant to dumps, page swaps, and hibernation.
 
-- **Current:** Using the `memsafe` crate as an interim solution
+- **Current:** A dedicated memory-protection abstraction is in place, with `memsafe` used behind that abstraction today
-- **Planned:** Custom implementation based on `mlock` (Unix) and `VirtualProtect` (Windows)
+- **Planned:** Additional backends can be introduced behind the same abstraction, including a custom implementation based on `mlock` (Unix) and `VirtualProtect` (Windows)

docs/superpowers/plans/2026-03-28-grant-creation-refactor.md

@@ -111,7 +111,7 @@ String shortAddress(List<int> bytes) {
 - [ ] **Step 2: Verify**
 
 ```sh
-cd useragent && dart analyze lib/screens/dashboard/evm/grants/create/utils.dart
+cd operator && dart analyze lib/screens/dashboard/evm/grants/create/utils.dart
 ```
 
 Expected: no errors.
@@ -168,7 +168,7 @@ class GrantCreation extends _$GrantCreation {
 - [ ] **Step 2: Run code generator**
 
 ```sh
-cd useragent && dart run build_runner build --delete-conflicting-outputs
+cd operator && dart run build_runner build --delete-conflicting-outputs
 ```
 
 Expected: generates `provider.freezed.dart` and `provider.g.dart`, no errors.
@@ -176,7 +176,7 @@ Expected: generates `provider.freezed.dart` and `provider.g.dart`, no errors.
 - [ ] **Step 3: Verify**
 
 ```sh
-cd useragent && dart analyze lib/screens/dashboard/evm/grants/create/provider.dart
+cd operator && dart analyze lib/screens/dashboard/evm/grants/create/provider.dart
 ```
 
 Expected: no errors.
@@ -204,7 +204,7 @@ jj describe -m "feat(grants): add GrantCreation provider (client selection + gra
 
 ```dart
 // lib/screens/dashboard/evm/grants/create/fields/client_picker_field.dart
-import 'package:arbiter/proto/user_agent.pb.dart';
+import 'package:arbiter/proto/operator.pb.dart';
 import 'package:arbiter/providers/sdk_clients/list.dart';
 import 'package:arbiter/screens/dashboard/evm/grants/create/provider.dart';
 import 'package:flutter/material.dart';
@@ -246,7 +246,7 @@ class ClientPickerField extends ConsumerWidget {
 ```dart
 // lib/screens/dashboard/evm/grants/create/fields/wallet_access_picker_field.dart
 import 'package:arbiter/proto/evm.pb.dart';
-import 'package:arbiter/proto/user_agent.pb.dart';
+import 'package:arbiter/proto/operator.pb.dart';
 import 'package:arbiter/providers/evm/evm.dart';
 import 'package:arbiter/providers/sdk_clients/wallet_access_list.dart';
 import 'package:arbiter/screens/dashboard/evm/grants/create/provider.dart';
@@ -522,7 +522,7 @@ class TransactionRateLimitField extends StatelessWidget {
 - [ ] **Step 8: Verify all field widgets**
 
 ```sh
-cd useragent && dart analyze lib/screens/dashboard/evm/grants/create/fields/
+cd operator && dart analyze lib/screens/dashboard/evm/grants/create/fields/
 ```
 
 Expected: no errors.
@@ -585,7 +585,7 @@ class SharedGrantFields extends StatelessWidget {
 - [ ] **Step 2: Verify**
 
 ```sh
-cd useragent && dart analyze lib/screens/dashboard/evm/grants/create/shared_grant_fields.dart
+cd operator && dart analyze lib/screens/dashboard/evm/grants/create/shared_grant_fields.dart
 ```
 
 Expected: no errors.
@@ -978,7 +978,7 @@ class _TokenVolumeLimitRow extends HookWidget {
 - [ ] **Step 4: Run code generator for token_transfer_grant.g.dart**
 
 ```sh
-cd useragent && dart run build_runner build --delete-conflicting-outputs
+cd operator && dart run build_runner build --delete-conflicting-outputs
 ```
 
 Expected: generates `token_transfer_grant.g.dart`, no errors.
@@ -986,7 +986,7 @@ Expected: generates `token_transfer_grant.g.dart`, no errors.
 - [ ] **Step 5: Verify**
 
 ```sh
-cd useragent && dart analyze lib/screens/dashboard/evm/grants/create/grants/
+cd operator && dart analyze lib/screens/dashboard/evm/grants/create/grants/
 ```
 
 Expected: no errors.
@@ -1265,7 +1265,7 @@ String _formatError(Object error) {
 - [ ] **Step 2: Verify the full create/ directory**
 
 ```sh
-cd useragent && dart analyze lib/screens/dashboard/evm/grants/create/
+cd operator && dart analyze lib/screens/dashboard/evm/grants/create/
 ```
 
 Expected: no errors.

docs/superpowers/plans/2026-03-28-grant-grid-view.md

@@ -14,24 +14,24 @@
 
 | File | Action | Responsibility |
 |---|---|---|
-| `useragent/lib/theme/palette.dart` | Modify | Add `Palette.token` (indigo accent for token-transfer cards) |
+| `operator/lib/theme/palette.dart` | Modify | Add `Palette.token` (indigo accent for token-transfer cards) |
-| `useragent/lib/features/connection/evm/wallet_access.dart` | Modify | Add `listAllWalletAccesses()` function |
+| `operator/lib/features/connection/evm/wallet_access.dart` | Modify | Add `listAllWalletAccesses()` function |
-| `useragent/lib/providers/sdk_clients/wallet_access_list.dart` | Create | `WalletAccessListProvider` — fetches full wallet access list with IDs |
+| `operator/lib/providers/sdk_clients/wallet_access_list.dart` | Create | `WalletAccessListProvider` — fetches full wallet access list with IDs |
-| `useragent/lib/screens/dashboard/evm/grants/widgets/grant_card.dart` | Create | `GrantCard` widget — watches enrichment providers + revoke mutation; one card per grant |
+| `operator/lib/screens/dashboard/evm/grants/widgets/grant_card.dart` | Create | `GrantCard` widget — watches enrichment providers + revoke mutation; one card per grant |
-| `useragent/lib/screens/dashboard/evm/grants/grants.dart` | Create | `EvmGrantsScreen` — watches `evmGrantsProvider`; handles loading/error/empty/data states; renders `GrantCard` list |
+| `operator/lib/screens/dashboard/evm/grants/grants.dart` | Create | `EvmGrantsScreen` — watches `evmGrantsProvider`; handles loading/error/empty/data states; renders `GrantCard` list |
-| `useragent/lib/router.dart` | Modify | Register `EvmGrantsRoute` in dashboard children |
+| `operator/lib/router.dart` | Modify | Register `EvmGrantsRoute` in dashboard children |
-| `useragent/lib/screens/dashboard.dart` | Modify | Add Grants entry to `routes` list and `NavigationDestination` list |
+| `operator/lib/screens/dashboard.dart` | Modify | Add Grants entry to `routes` list and `NavigationDestination` list |
 
 ---
 
 ## Task 1: Add `Palette.token`
 
 **Files:**
-- Modify: `useragent/lib/theme/palette.dart`
+- Modify: `operator/lib/theme/palette.dart`
 
 - [ ] **Step 1: Add the color**
 
-Replace the contents of `useragent/lib/theme/palette.dart` with:
+Replace the contents of `operator/lib/theme/palette.dart` with:
 
 ```dart
 import 'package:flutter/material.dart';
@@ -48,7 +48,7 @@ class Palette {
 - [ ] **Step 2: Verify**
 
 ```sh
-cd useragent && flutter analyze lib/theme/palette.dart
+cd operator && flutter analyze lib/theme/palette.dart
 ```
 
 Expected: no issues.
@@ -65,20 +65,20 @@ jj new
 ## Task 2: Add `listAllWalletAccesses` feature function
 
 **Files:**
-- Modify: `useragent/lib/features/connection/evm/wallet_access.dart`
+- Modify: `operator/lib/features/connection/evm/wallet_access.dart`
 
 `readClientWalletAccess` (existing) filters the list to one client's wallet IDs and returns `Set<int>`. This new function returns the complete unfiltered list with row IDs so the grant cards can resolve wallet_access_id → wallet + client.
 
 - [ ] **Step 1: Append function**
 
-Add at the bottom of `useragent/lib/features/connection/evm/wallet_access.dart`:
+Add at the bottom of `operator/lib/features/connection/evm/wallet_access.dart`:
 
 ```dart
 Future<List<SdkClientWalletAccess>> listAllWalletAccesses(
   Connection connection,
 ) async {
   final response = await connection.ask(
-    UserAgentRequest(listWalletAccess: Empty()),
+    OperatorRequest(listWalletAccess: Empty()),
   );
   if (!response.hasListWalletAccessResponse()) {
     throw Exception(
@@ -97,7 +97,7 @@ Each returned `SdkClientWalletAccess` has:
 - [ ] **Step 2: Verify**
 
 ```sh
-cd useragent && flutter analyze lib/features/connection/evm/wallet_access.dart
+cd operator && flutter analyze lib/features/connection/evm/wallet_access.dart
 ```
 
 Expected: no issues.
@@ -114,18 +114,18 @@ jj new
 ## Task 3: Create `WalletAccessListProvider`
 
 **Files:**
-- Create: `useragent/lib/providers/sdk_clients/wallet_access_list.dart`
+- Create: `operator/lib/providers/sdk_clients/wallet_access_list.dart`
-- Generated: `useragent/lib/providers/sdk_clients/wallet_access_list.g.dart`
+- Generated: `operator/lib/providers/sdk_clients/wallet_access_list.g.dart`
 
 Mirrors the structure of `EvmGrants` in `providers/evm/evm_grants.dart` — class-based `@riverpod` with a `refresh()` method.
 
 - [ ] **Step 1: Write the provider**
 
-Create `useragent/lib/providers/sdk_clients/wallet_access_list.dart`:
+Create `operator/lib/providers/sdk_clients/wallet_access_list.dart`:
 
 ```dart
 import 'package:arbiter/features/connection/evm/wallet_access.dart';
-import 'package:arbiter/proto/user_agent.pb.dart';
+import 'package:arbiter/proto/operator.pb.dart';
 import 'package:arbiter/providers/connection/connection_manager.dart';
 import 'package:mtcore/markettakers.dart';
 import 'package:riverpod_annotation/riverpod_annotation.dart';
@@ -165,15 +165,15 @@ class WalletAccessList extends _$WalletAccessList {
 - [ ] **Step 2: Run code generation**
 
 ```sh
-cd useragent && dart run build_runner build --delete-conflicting-outputs
+cd operator && dart run build_runner build --delete-conflicting-outputs
 ```
 
-Expected: `useragent/lib/providers/sdk_clients/wallet_access_list.g.dart` created. No errors.
+Expected: `operator/lib/providers/sdk_clients/wallet_access_list.g.dart` created. No errors.
 
 - [ ] **Step 3: Verify**
 
 ```sh
-cd useragent && flutter analyze lib/providers/sdk_clients/
+cd operator && flutter analyze lib/providers/sdk_clients/
 ```
 
 Expected: no issues.
@@ -190,26 +190,26 @@ jj new
 ## Task 4: Create `GrantCard` widget
 
 **Files:**
-- Create: `useragent/lib/screens/dashboard/evm/grants/widgets/grant_card.dart`
+- Create: `operator/lib/screens/dashboard/evm/grants/widgets/grant_card.dart`
 
 This widget owns all per-card logic: enrichment lookups, revoke action, and rebuild scope. The screen only passes it a `GrantEntry` — the card fetches everything else itself.
 
 **Key types:**
 - `GrantEntry` (from `proto/evm.pb.dart`): `.id`, `.shared.walletAccessId`, `.shared.chainId`, `.specific.whichGrant()`
 - `SpecificGrant_Grant.etherTransfer` / `.tokenTransfer` — enum values for the oneof
-- `SdkClientWalletAccess` (from `proto/user_agent.pb.dart`): `.id`, `.access.walletId`, `.access.sdkClientId`
+- `SdkClientWalletAccess` (from `proto/operator.pb.dart`): `.id`, `.access.walletId`, `.access.sdkClientId`
 - `WalletEntry` (from `proto/evm.pb.dart`): `.id`, `.address` (List<int>)
-- `SdkClientEntry` (from `proto/user_agent.pb.dart`): `.id`, `.info.name`
+- `SdkClientEntry` (from `proto/operator.pb.dart`): `.id`, `.info.name`
 - `revokeEvmGrantMutation` — `Mutation<void>` (global; all revoke buttons disable together while any revoke is in flight)
 - `executeRevokeEvmGrant(ref, grantId: int)` — `Future<void>`
 
 - [ ] **Step 1: Write the widget**
 
-Create `useragent/lib/screens/dashboard/evm/grants/widgets/grant_card.dart`:
+Create `operator/lib/screens/dashboard/evm/grants/widgets/grant_card.dart`:
 
 ```dart
 import 'package:arbiter/proto/evm.pb.dart';
-import 'package:arbiter/proto/user_agent.pb.dart';
+import 'package:arbiter/proto/operator.pb.dart';
 import 'package:arbiter/providers/evm/evm.dart';
 import 'package:arbiter/providers/evm/evm_grants.dart';
 import 'package:arbiter/providers/sdk_clients/list.dart';
@@ -438,7 +438,7 @@ class GrantCard extends ConsumerWidget {
 - [ ] **Step 2: Verify**
 
 ```sh
-cd useragent && flutter analyze lib/screens/dashboard/evm/grants/widgets/grant_card.dart
+cd operator && flutter analyze lib/screens/dashboard/evm/grants/widgets/grant_card.dart
 ```
 
 Expected: no issues.
@@ -455,13 +455,13 @@ jj new
 ## Task 5: Create `EvmGrantsScreen`
 
 **Files:**
-- Create: `useragent/lib/screens/dashboard/evm/grants/grants.dart`
+- Create: `operator/lib/screens/dashboard/evm/grants/grants.dart`
 
 The screen watches only `evmGrantsProvider` for top-level state (loading / error / no connection / empty / data). When there is data it renders a list of `GrantCard` widgets — each card manages its own enrichment subscriptions.
 
 - [ ] **Step 1: Write the screen**
 
-Create `useragent/lib/screens/dashboard/evm/grants/grants.dart`:
+Create `operator/lib/screens/dashboard/evm/grants/grants.dart`:
 
 ```dart
 import 'package:arbiter/proto/evm.pb.dart';
@@ -702,7 +702,7 @@ class EvmGrantsScreen extends ConsumerWidget {
 - [ ] **Step 2: Verify**
 
 ```sh
-cd useragent && flutter analyze lib/screens/dashboard/evm/grants/
+cd operator && flutter analyze lib/screens/dashboard/evm/grants/
 ```
 
 Expected: no issues.
@@ -719,13 +719,13 @@ jj new
 ## Task 6: Wire router and dashboard tab
 
 **Files:**
-- Modify: `useragent/lib/router.dart`
+- Modify: `operator/lib/router.dart`
-- Modify: `useragent/lib/screens/dashboard.dart`
+- Modify: `operator/lib/screens/dashboard.dart`
-- Regenerated: `useragent/lib/router.gr.dart`
+- Regenerated: `operator/lib/router.gr.dart`
 
 - [ ] **Step 1: Add route to `router.dart`**
 
-Replace the contents of `useragent/lib/router.dart` with:
+Replace the contents of `operator/lib/router.dart` with:
 
 ```dart
 import 'package:auto_route/auto_route.dart';
@@ -759,7 +759,7 @@ class Router extends RootStackRouter {
 
 - [ ] **Step 2: Update `dashboard.dart`**
 
-In `useragent/lib/screens/dashboard.dart`, replace the `routes` constant:
+In `operator/lib/screens/dashboard.dart`, replace the `routes` constant:
 
 ```dart
 final routes = [
@@ -800,7 +800,7 @@ destinations: const [
 - [ ] **Step 3: Regenerate router**
 
 ```sh
-cd useragent && dart run build_runner build --delete-conflicting-outputs
+cd operator && dart run build_runner build --delete-conflicting-outputs
 ```
 
 Expected: `lib/router.gr.dart` updated, `EvmGrantsRoute` now available, no errors.
@@ -808,7 +808,7 @@ Expected: `lib/router.gr.dart` updated, `EvmGrantsRoute` now available, no error
 - [ ] **Step 4: Full project verify**
 
 ```sh
-cd useragent && flutter analyze
+cd operator && flutter analyze
 ```
 
 Expected: no issues.

docs/superpowers/specs/2026-03-28-grant-grid-view-design.md

@@ -4,7 +4,7 @@
 
 ## Overview
 
-Add a "Grants" dashboard tab to the Flutter user-agent app that displays all EVM grants as a card-based grid. Each card shows a compact summary (type, chain, wallet address, client name) with a revoke action. The tab integrates into the existing `AdaptiveScaffold` navigation alongside Wallets, Clients, and About.
+Add a "Grants" dashboard tab to the Flutter operator app that displays all EVM grants as a card-based grid. Each card shows a compact summary (type, chain, wallet address, client name) with a revoke action. The tab integrates into the existing `AdaptiveScaffold` navigation alongside Wallets, Clients, and About.
 
 ## Scope
 
@@ -23,7 +23,7 @@ Add a "Grants" dashboard tab to the Flutter user-agent app that displays all EVM
 
 ### `walletAccessListProvider`
 
-**File:** `useragent/lib/providers/sdk_clients/wallet_access_list.dart`
+**File:** `operator/lib/providers/sdk_clients/wallet_access_list.dart`
 
 - `@riverpod` class, watches `connectionManagerProvider.future`
 - Returns `List<SdkClientWalletAccess>?` (null when not connected)
@@ -85,7 +85,7 @@ NavigationDestination(
 
 ## Screen: `EvmGrantsScreen`
 
-**File:** `useragent/lib/screens/dashboard/evm/grants/grants.dart`
+**File:** `operator/lib/screens/dashboard/evm/grants/grants.dart`
 
 ```
 Scaffold

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 +113,44 @@ 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 = "1.95.0"
 backend = "core:rust"

mise.toml

@@ -1,22 +1,24 @@
 [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 = "1.95.0", 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']
+sources = ['protobufs/*.proto', 'protobufs/**/*.proto']
-outputs = ['useragent/lib/proto/*']
+outputs = ['useragent/lib/proto/**']
 run = '''
 dart pub global activate protoc_plugin && \
-protoc --dart_out=grpc:useragent/lib/proto --proto_path=protobufs/ protobufs/*.proto
+protoc --dart_out=grpc:useragent/lib/proto --proto_path=protobufs/ $(find protobufs -name '*.proto' | sort)
 '''

protobufs/arbiter.proto

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

protobufs/client.proto

@@ -2,63 +2,24 @@ syntax = "proto3";
 
 package arbiter.client;
 
-import "evm.proto";
+import "client/auth.proto";
-import "google/protobuf/empty.proto";
+import "client/evm.proto";
-
+import "client/vault.proto";
-message ClientInfo {
-  string name = 1;
-  optional string description = 2;
-  optional string version = 3;
-}
-
-message AuthChallengeRequest {
-  bytes pubkey = 1;
-  ClientInfo client_info = 2;
-}
-
-message AuthChallenge {
-  bytes pubkey = 1;
-  int32 nonce = 2;
-}
-
-message AuthChallengeSolution {
-  bytes signature = 1;
-}
-
-enum AuthResult {
-  AUTH_RESULT_UNSPECIFIED = 0;
-  AUTH_RESULT_SUCCESS = 1;
-  AUTH_RESULT_INVALID_KEY = 2;
-  AUTH_RESULT_INVALID_SIGNATURE = 3;
-  AUTH_RESULT_APPROVAL_DENIED = 4;
-  AUTH_RESULT_NO_USER_AGENTS_ONLINE = 5;
-  AUTH_RESULT_INTERNAL = 6;
-}
-
-enum VaultState {
-  VAULT_STATE_UNSPECIFIED = 0;
-  VAULT_STATE_UNBOOTSTRAPPED = 1;
-  VAULT_STATE_SEALED = 2;
-  VAULT_STATE_UNSEALED = 3;
-  VAULT_STATE_ERROR = 4;
-}
 
 message ClientRequest {
   int32 request_id = 4;
   oneof payload {
-    AuthChallengeRequest auth_challenge_request = 1;
+    auth.Request auth = 1;
-    AuthChallengeSolution auth_challenge_solution = 2;
+    vault.Request vault = 2;
-    google.protobuf.Empty query_vault_state = 3;
+    evm.Request evm = 3;
   }
 }
 
 message ClientResponse {
   optional int32 request_id = 7;
   oneof payload {
-    AuthChallenge auth_challenge = 1;
+    auth.Response auth = 1;
-    AuthResult auth_result = 2;
+    vault.Response vault = 2;
-    arbiter.evm.EvmSignTransactionResponse evm_sign_transaction = 3;
+    evm.Response evm = 3;
-    arbiter.evm.EvmAnalyzeTransactionResponse evm_analyze_transaction = 4;
-    VaultState vault_state = 6;
   }
 }

protobufs/client/auth.proto

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

protobufs/client/evm.proto

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

protobufs/client/vault.proto

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

protobufs/evm.proto

@@ -4,6 +4,7 @@ package arbiter.evm;
 
 import "google/protobuf/empty.proto";
 import "google/protobuf/timestamp.proto";
+import "shared/evm.proto";
 
 enum EvmError {
   EVM_ERROR_UNSPECIFIED = 0;
@@ -74,71 +75,7 @@ message SpecificGrant {
   }
 }
 
-message EtherTransferMeaning {
+// --- Operator grant management ---
-  bytes to = 1; // 20-byte Ethereum address
-  bytes value = 2; // U256 as big-endian bytes
-}
-
-message TokenInfo {
-  string symbol = 1;
-  bytes address = 2; // 20-byte Ethereum address
-  uint64 chain_id = 3;
-}
-
-// Mirror of token_transfers::Meaning
-message TokenTransferMeaning {
-  TokenInfo token = 1;
-  bytes to = 2; // 20-byte Ethereum address
-  bytes value = 3; // U256 as big-endian bytes
-}
-
-// Mirror of policies::SpecificMeaning
-message SpecificMeaning {
-  oneof meaning {
-    EtherTransferMeaning ether_transfer = 1;
-    TokenTransferMeaning token_transfer = 2;
-  }
-}
-
-// --- Eval error types ---
-message GasLimitExceededViolation {
-  optional bytes max_gas_fee_per_gas = 1; // U256 as big-endian bytes
-  optional bytes max_priority_fee_per_gas = 2; // U256 as big-endian bytes
-}
-
-message EvalViolation {
-  oneof kind {
-    bytes invalid_target = 1; // 20-byte Ethereum address
-    GasLimitExceededViolation gas_limit_exceeded = 2;
-    google.protobuf.Empty rate_limit_exceeded = 3;
-    google.protobuf.Empty volumetric_limit_exceeded = 4;
-    google.protobuf.Empty invalid_time = 5;
-    google.protobuf.Empty invalid_transaction_type = 6;
-  }
-}
-
-// Transaction was classified but no grant covers it
-message NoMatchingGrantError {
-  SpecificMeaning meaning = 1;
-}
-
-// Transaction was classified and a grant was found, but constraints were violated
-message PolicyViolationsError {
-  SpecificMeaning meaning = 1;
-  repeated EvalViolation violations = 2;
-}
-
-// top-level error returned when transaction evaluation fails
-message TransactionEvalError {
-  oneof kind {
-    google.protobuf.Empty contract_creation_not_supported = 1;
-    google.protobuf.Empty unsupported_transaction_type = 2;
-    NoMatchingGrantError no_matching_grant = 3;
-    PolicyViolationsError policy_violations = 4;
-  }
-}
-
-// --- UserAgent grant management ---
 message EvmGrantCreateRequest {
   SharedSettings shared = 1;
   SpecificGrant specific = 2;
@@ -197,7 +134,7 @@ message EvmSignTransactionRequest {
 message EvmSignTransactionResponse {
   oneof result {
     bytes signature = 1; // 65-byte signature: r[32] || s[32] || v[1]
-    TransactionEvalError eval_error = 2;
+    arbiter.shared.evm.TransactionEvalError eval_error = 2;
     EvmError error = 3;
   }
 }
@@ -209,8 +146,8 @@ message EvmAnalyzeTransactionRequest {
 
 message EvmAnalyzeTransactionResponse {
   oneof result {
-    SpecificMeaning meaning = 1;
+    arbiter.shared.evm.SpecificMeaning meaning = 1;
-    TransactionEvalError eval_error = 2;
+    arbiter.shared.evm.TransactionEvalError eval_error = 2;
     EvmError error = 3;
   }
 }

protobufs/operator.proto

@@ -0,0 +1,28 @@
+syntax = "proto3";
+
+package arbiter.operator;
+
+import "operator/auth.proto";
+import "operator/evm.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;
+  }
+}
+
+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;
+  }
+}

protobufs/operator/auth.proto

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

protobufs/operator/evm.proto

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

protobufs/operator/sdk_client.proto

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

protobufs/operator/vault/bootstrap.proto

@@ -0,0 +1,24 @@
+syntax = "proto3";
+
+package arbiter.operator.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/operator/vault/unseal.proto

@@ -0,0 +1,37 @@
+syntax = "proto3";
+
+package arbiter.operator.vault.unseal;
+
+message UnsealStart {
+  bytes client_pubkey = 1;
+}
+
+message UnsealStartResponse {
+  bytes server_pubkey = 1;
+}
+message UnsealEncryptedKey {
+  bytes nonce = 1;
+  bytes ciphertext = 2;
+  bytes associated_data = 3;
+}
+
+enum UnsealResult {
+  UNSEAL_RESULT_UNSPECIFIED = 0;
+  UNSEAL_RESULT_SUCCESS = 1;
+  UNSEAL_RESULT_INVALID_KEY = 2;
+  UNSEAL_RESULT_UNBOOTSTRAPPED = 3;
+}
+
+message Request {
+  oneof payload {
+    UnsealStart start = 1;
+    UnsealEncryptedKey encrypted_key = 2;
+  }
+}
+
+message Response {
+  oneof payload {
+    UnsealStartResponse start = 1;
+    UnsealResult result = 2;
+  }
+}

protobufs/operator/vault/vault.proto

@@ -0,0 +1,24 @@
+syntax = "proto3";
+
+package arbiter.operator.vault;
+
+import "google/protobuf/empty.proto";
+import "shared/vault.proto";
+import "operator/vault/bootstrap.proto";
+import "operator/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;
+  }
+}

protobufs/shared/client.proto

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

protobufs/shared/evm.proto

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

protobufs/shared/vault.proto

@@ -0,0 +1,11 @@
+syntax = "proto3";
+
+package arbiter.shared;
+
+enum VaultState {
+  VAULT_STATE_UNSPECIFIED = 0;
+  VAULT_STATE_UNBOOTSTRAPPED = 1;
+  VAULT_STATE_SEALED = 2;
+  VAULT_STATE_UNSEALED = 3;
+  VAULT_STATE_ERROR = 4;
+}

protobufs/user_agent.proto

@@ -1,199 +0,0 @@
-syntax = "proto3";
-
-package arbiter.user_agent;
-
-import "client.proto";
-import "evm.proto";
-import "google/protobuf/empty.proto";
-
-enum KeyType {
-  KEY_TYPE_UNSPECIFIED = 0;
-  KEY_TYPE_ED25519 = 1;
-  KEY_TYPE_ECDSA_SECP256K1 = 2;
-  KEY_TYPE_RSA = 3;
-}
-
-// --- SDK client management ---
-
-enum SdkClientError {
-  SDK_CLIENT_ERROR_UNSPECIFIED = 0;
-  SDK_CLIENT_ERROR_ALREADY_EXISTS = 1;
-  SDK_CLIENT_ERROR_NOT_FOUND = 2;
-  SDK_CLIENT_ERROR_HAS_RELATED_DATA = 3; // hard-delete blocked by FK (client has grants or transaction logs)
-  SDK_CLIENT_ERROR_INTERNAL = 4;
-}
-
-message SdkClientRevokeRequest {
-  int32 client_id = 1;
-}
-
-message SdkClientEntry {
-  int32 id = 1;
-  bytes pubkey = 2;
-  arbiter.client.ClientInfo info = 3;
-  int32 created_at = 4;
-}
-
-message SdkClientList {
-  repeated SdkClientEntry clients = 1;
-}
-
-message SdkClientRevokeResponse {
-  oneof result {
-    google.protobuf.Empty ok = 1;
-    SdkClientError error = 2;
-  }
-}
-
-message SdkClientListResponse {
-  oneof result {
-    SdkClientList clients = 1;
-    SdkClientError error = 2;
-  }
-}
-
-message AuthChallengeRequest {
-  bytes pubkey = 1;
-  optional string bootstrap_token = 2;
-  KeyType key_type = 3;
-}
-
-message AuthChallenge {
-  int32 nonce = 2;
-  reserved 1;
-}
-
-message AuthChallengeSolution {
-  bytes signature = 1;
-}
-
-enum AuthResult {
-  AUTH_RESULT_UNSPECIFIED = 0;
-  AUTH_RESULT_SUCCESS = 1;
-  AUTH_RESULT_INVALID_KEY = 2;
-  AUTH_RESULT_INVALID_SIGNATURE = 3;
-  AUTH_RESULT_BOOTSTRAP_REQUIRED = 4;
-  AUTH_RESULT_TOKEN_INVALID = 5;
-  AUTH_RESULT_INTERNAL = 6;
-}
-
-message UnsealStart {
-  bytes client_pubkey = 1;
-}
-
-message UnsealStartResponse {
-  bytes server_pubkey = 1;
-}
-message UnsealEncryptedKey {
-  bytes nonce = 1;
-  bytes ciphertext = 2;
-  bytes associated_data = 3;
-}
-
-message BootstrapEncryptedKey {
-  bytes nonce = 1;
-  bytes ciphertext = 2;
-  bytes associated_data = 3;
-}
-
-enum UnsealResult {
-  UNSEAL_RESULT_UNSPECIFIED = 0;
-  UNSEAL_RESULT_SUCCESS = 1;
-  UNSEAL_RESULT_INVALID_KEY = 2;
-  UNSEAL_RESULT_UNBOOTSTRAPPED = 3;
-}
-
-enum BootstrapResult {
-  BOOTSTRAP_RESULT_UNSPECIFIED = 0;
-  BOOTSTRAP_RESULT_SUCCESS = 1;
-  BOOTSTRAP_RESULT_ALREADY_BOOTSTRAPPED = 2;
-  BOOTSTRAP_RESULT_INVALID_KEY = 3;
-}
-
-enum VaultState {
-  VAULT_STATE_UNSPECIFIED = 0;
-  VAULT_STATE_UNBOOTSTRAPPED = 1;
-  VAULT_STATE_SEALED = 2;
-  VAULT_STATE_UNSEALED = 3;
-  VAULT_STATE_ERROR = 4;
-}
-
-message SdkClientConnectionRequest {
-  bytes pubkey = 1;
-  arbiter.client.ClientInfo info = 2;
-}
-
-message SdkClientConnectionResponse {
-  bool approved = 1;
-  bytes pubkey = 2;
-}
-
-message SdkClientConnectionCancel {
-  bytes pubkey = 1;
-}
-
-message WalletAccess {
-  int32 wallet_id = 1;
-  int32 sdk_client_id = 2;
-}
-
-message SdkClientWalletAccess {
-  int32 id = 1;
-  WalletAccess access = 2;
-}
-
-message SdkClientGrantWalletAccess {
-  repeated WalletAccess accesses = 1;
-}
-
-message SdkClientRevokeWalletAccess {
-  repeated int32 accesses = 1;
-}
-
-message ListWalletAccessResponse {
-  repeated SdkClientWalletAccess accesses = 1;
-}
-
-message UserAgentRequest {
-  int32 id = 16;
-  oneof payload {
-    AuthChallengeRequest auth_challenge_request = 1;
-    AuthChallengeSolution auth_challenge_solution = 2;
-    UnsealStart unseal_start = 3;
-    UnsealEncryptedKey unseal_encrypted_key = 4;
-    google.protobuf.Empty query_vault_state = 5;
-    google.protobuf.Empty evm_wallet_create = 6;
-    google.protobuf.Empty evm_wallet_list = 7;
-    arbiter.evm.EvmGrantCreateRequest evm_grant_create = 8;
-    arbiter.evm.EvmGrantDeleteRequest evm_grant_delete = 9;
-    arbiter.evm.EvmGrantListRequest evm_grant_list = 10;
-    SdkClientConnectionResponse sdk_client_connection_response = 11;
-    SdkClientRevokeRequest sdk_client_revoke = 12;
-    google.protobuf.Empty sdk_client_list = 13;
-    BootstrapEncryptedKey bootstrap_encrypted_key = 14;
-    SdkClientGrantWalletAccess grant_wallet_access = 15;
-    SdkClientRevokeWalletAccess revoke_wallet_access = 17;
-    google.protobuf.Empty list_wallet_access = 18;
-  }
-}
-message UserAgentResponse {
-  optional int32 id = 16;
-  oneof payload {
-    AuthChallenge auth_challenge = 1;
-    AuthResult auth_result = 2;
-    UnsealStartResponse unseal_start_response = 3;
-    UnsealResult unseal_result = 4;
-    VaultState vault_state = 5;
-    arbiter.evm.WalletCreateResponse evm_wallet_create = 6;
-    arbiter.evm.WalletListResponse evm_wallet_list = 7;
-    arbiter.evm.EvmGrantCreateResponse evm_grant_create = 8;
-    arbiter.evm.EvmGrantDeleteResponse evm_grant_delete = 9;
-    arbiter.evm.EvmGrantListResponse evm_grant_list = 10;
-    SdkClientConnectionRequest sdk_client_connection_request = 11;
-    SdkClientConnectionCancel sdk_client_connection_cancel = 12;
-    SdkClientRevokeResponse sdk_client_revoke_response = 13;
-    SdkClientListResponse sdk_client_list_response = 14;
-    BootstrapResult bootstrap_result = 15;
-    ListWalletAccessResponse list_wallet_access_response = 17;
-  }
-}

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 +4,167 @@ members = [
 ]
 resolver = "3"
 
-[workspace.lints.clippy]
-disallowed-methods = "deny"
-
 
 [workspace.dependencies]
-tonic = { version = "0.14.5", features = [
+alloy = "2.0.4"
-    "deflate",
-    "gzip",
-    "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"
-rustls = { version = "0.23.37", features = ["aws-lc-rs"] }
-smlang = "0.8.0"
-miette = { version = "7.6.0", features = ["fancy", "serde"] }
-thiserror = "2.0.18"
 async-trait = "0.1.89"
+base64 = "0.22.1"
+chrono = { version = "0.4.44", features = ["serde"] }
 futures = "0.3.32"
-tokio-stream = { version = "0.1.18", features = ["full"] }
-kameo = "0.19.2"
-prost-types = { version = "0.14.3", features = ["chrono"] }
-x25519-dalek = { version = "2.0.1", features = ["getrandom"] }
-rstest = "0.26.1"
-rustls-pki-types = "1.14.0"
-alloy = "1.7.3"
-rcgen = { version = "0.14.7", features = [
-    "aws_lc_rs",
-    "pem",
-    "x509-parser",
-    "zeroize",
-], default-features = false }
 k256 = { version = "0.13.4", features = ["ecdsa", "pkcs8"] }
-rsa = { version = "0.9", features = ["sha2"] }
+kameo = {git = "https://github.com/hdbg/kameo.git", rev = "805b417"}
-sha2 = "0.10"
+kameo_actors = {git = "https://github.com/hdbg/kameo.git", rev = "805b417"}
-spki = "0.7"
+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"
+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"
+tokio = { version = "1.52.1", features = ["full"] }
+tokio-stream = { version = "0.1.18", features = ["full"] }
+tonic = { version = "0.14.5", features = [ "deflate", "gzip", "tls-connect-info", "zstd" ] }
+tracing = "0.1.44"
+x25519-dalek = { version = "2.0.1", features = ["getrandom"] }
+
+[workspace.lints.rust]
+missing_unsafe_on_extern = "deny"
+unsafe_attr_outside_unsafe = "deny"
+unsafe_op_in_unsafe_fn = "deny"
+unstable_features = "deny"
+
+deprecated_safe_2024 = "warn"
+ffi_unwind_calls = "warn"
+linker_messages = "warn"
+
+elided_lifetimes_in_paths = "warn"
+explicit_outlives_requirements = "warn"
+impl-trait-overcaptures = "warn"
+impl-trait-redundant-captures = "warn"
+redundant_lifetimes = "warn"
+single_use_lifetimes = "warn"
+unused_lifetimes = "warn"
+
+macro_use_extern_crate = "warn"
+redundant_imports = "warn"
+unused_import_braces = "warn"
+unused_macro_rules = "warn"
+unused_qualifications = "warn"
+
+unit_bindings = "warn"
+
+# missing_docs = "warn" # ENABLE BY THE FIRST MAJOR VERSION!!
+unnameable_types = "warn"
+
+[workspace.lints.clippy]
+derive_partial_eq_without_eq = "allow" 
+future_not_send = "allow"
+inconsistent_struct_constructor = "allow"
+inline_always = "allow"
+missing_errors_doc = "allow"
+missing_fields_in_debug = "allow"
+missing_panics_doc = "allow"
+must_use_candidate = "allow"
+needless_pass_by_ref_mut = "allow"
+pub_underscore_fields = "allow"
+redundant_pub_crate = "allow" 
+uninhabited_references = "allow" # safe with unsafe_code = "forbid" and standard uninhabited pattern (match *self {})
+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
+
+# 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"
+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

@@ -1,40 +1,50 @@
-use arbiter_proto::{
-    ClientMetadata, format_challenge,
-    proto::client::{
-        AuthChallengeRequest, AuthChallengeSolution, AuthResult, ClientInfo as ProtoClientInfo,
-        ClientRequest, client_request::Payload as ClientRequestPayload,
-        client_response::Payload as ClientResponsePayload,
-    },
-};
-use ed25519_dalek::Signer as _;
-
 use crate::{
     storage::StorageError,
     transport::{ClientTransport, next_request_id},
 };
+use arbiter_crypto::authn::{self, CLIENT_CONTEXT, SigningKey};
+use arbiter_proto::{
+    ClientMetadata,
+    proto::{
+        client::{
+            ClientRequest,
+            auth::{
+                self as proto_auth, AuthChallenge, AuthChallengeRequest, AuthChallengeSolution,
+                AuthResult, request::Payload as AuthRequestPayload,
+                response::Payload as AuthResponsePayload,
+            },
+            client_request::Payload as ClientRequestPayload,
+            client_response::Payload as ClientResponsePayload,
+        },
+        shared::ClientInfo as ProtoClientInfo,
+    },
+};
+
+use chrono::DateTime;
 
 #[derive(Debug, thiserror::Error)]
 pub enum AuthError {
+    #[error("Server sent invalid auth challenge")]
+    InvalidChallenge,
+    #[error("Client approval denied by Operator")]
+    ApprovalDenied,
     #[error("Auth challenge was not returned by server")]
     MissingAuthChallenge,
 
-    #[error("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
@@ -46,21 +56,21 @@ 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::AuthChallengeRequest(
+            payload: Some(ClientRequestPayload::Auth(proto_auth::Request {
-                AuthChallengeRequest {
+                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,
                         version: metadata.version,
                     }),
-                },
+                })),
-            )),
+            })),
         })
         .await
         .map_err(|_| AuthError::UnexpectedAuthResponse)
@@ -68,7 +78,7 @@ async fn send_auth_challenge_request(
 
 async fn receive_auth_challenge(
     transport: &mut ClientTransport,
-) -> std::result::Result<arbiter_proto::proto::client::AuthChallenge, AuthError> {
+) -> Result<AuthChallenge, AuthError> {
     let response = transport
         .recv()
         .await
@@ -76,58 +86,73 @@ async fn receive_auth_challenge(
 
     let payload = response.payload.ok_or(AuthError::MissingAuthChallenge)?;
     match payload {
-        ClientResponsePayload::AuthChallenge(challenge) => Ok(challenge),
+        ClientResponsePayload::Auth(response) => match response.payload {
-        ClientResponsePayload::AuthResult(result) => Err(map_auth_result(result)),
+            Some(AuthResponsePayload::Challenge(challenge)) => Ok(challenge),
+            Some(AuthResponsePayload::Result(result)) => Err(map_auth_result(result)),
+            None => Err(AuthError::MissingAuthChallenge),
+        },
         _ => Err(AuthError::UnexpectedAuthResponse),
     }
 }
 
 async fn send_auth_challenge_solution(
     transport: &mut ClientTransport,
-    key: &ed25519_dalek::SigningKey,
+    key: &SigningKey,
-    challenge: arbiter_proto::proto::client::AuthChallenge,
+    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 {
             request_id: next_request_id(),
-            payload: Some(ClientRequestPayload::AuthChallengeSolution(
+            payload: Some(ClientRequestPayload::Auth(proto_auth::Request {
-                AuthChallengeSolution { signature },
+                payload: Some(AuthRequestPayload::ChallengeSolution(
-            )),
+                    AuthChallengeSolution { signature },
+                )),
+            })),
         })
         .await
         .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
         .map_err(|_| AuthError::UnexpectedAuthResponse)?;
 
-    let payload = response
+    let payload = response.payload.ok_or(AuthError::UnexpectedAuthResponse)?;
-        .payload
-        .ok_or(AuthError::UnexpectedAuthResponse)?;
     match payload {
-        ClientResponsePayload::AuthResult(result)
+        ClientResponsePayload::Auth(response) => match response.payload {
-            if AuthResult::try_from(result).ok() == Some(AuthResult::Success) =>
+            Some(AuthResponsePayload::Result(result))
-        {
+                if AuthResult::try_from(result).ok() == Some(AuthResult::Success) =>
-            Ok(())
+            {
-        }
+                Ok(())
-        ClientResponsePayload::AuthResult(result) => Err(map_auth_result(result)),
+            }
+            Some(AuthResponsePayload::Result(result)) => Err(map_auth_result(result)),
+            _ => Err(AuthError::UnexpectedAuthResponse),
+        },
         _ => Err(AuthError::UnexpectedAuthResponse),
     }
 }
 
-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

@@ -1,9 +1,7 @@
-
-use std::io::{self, Write};
-
 use arbiter_client::ArbiterClient;
 use arbiter_proto::{ClientMetadata, url::ArbiterUrl};
-use tonic::ConnectError;
+
+use std::io::{self, Write};
 
 #[tokio::main]
 async fn main() {
@@ -23,8 +21,6 @@ async fn main() {
         return;
     }
 
-   
-
     let url = match ArbiterUrl::try_from(input) {
         Ok(url) => url,
         Err(err) => {
@@ -33,16 +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

@@ -1,45 +1,55 @@
-use arbiter_proto::{ClientMetadata, proto::arbiter_service_client::ArbiterServiceClient, url::ArbiterUrl};
+#[cfg(feature = "evm")]
+use crate::wallets::evm::ArbiterEvmWallet;
+use crate::{
+    StorageError,
+    auth::{AuthError, authenticate},
+    storage::{FileSigningKeyStorage, SigningKeyStorage},
+    transport::{BUFFER_LENGTH, ClientTransport},
+};
+use arbiter_crypto::authn::SigningKey;
+use arbiter_proto::{
+    ClientMetadata, proto::arbiter_service_client::ArbiterServiceClient, url::ArbiterUrl,
+};
+
 use std::sync::Arc;
 use tokio::sync::{Mutex, mpsc};
 use tokio_stream::wrappers::ReceiverStream;
 use tonic::transport::ClientTlsConfig;
 
-use crate::{
-    StorageError, auth::{AuthError, authenticate}, storage::{FileSigningKeyStorage, SigningKeyStorage}, transport::{BUFFER_LENGTH, ClientTransport}
-};
-
-#[cfg(feature = "evm")]
-use crate::wallets::evm::ArbiterEvmWallet;
-
 #[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
     }
@@ -48,7 +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
     }
@@ -56,15 +66,16 @@ 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);
 
-        let channel = tonic::transport::Channel::from_shared(format!("https://{}:{}", url.host, url.port))?
+        let channel =
-            .tls_config(tls)?
+            tonic::transport::Channel::from_shared(format!("https://{}:{}", url.host, url.port))?
-            .connect()
+                .tls_config(tls)?
-            .await?;
+                .connect()
+                .await?;
 
         let mut client = ArbiterServiceClient::new(channel);
         let (tx, rx) = mpsc::channel(BUFFER_LENGTH);
@@ -83,7 +94,8 @@ impl ArbiterClient {
     }
 
     #[cfg(feature = "evm")]
-    pub async fn evm_wallets(&self) -> Result<Vec<ArbiterEvmWallet>, Error> {
+    #[expect(clippy::unused_async, reason = "false positive")]
+    pub async fn evm_wallets(&self) -> Result<Vec<ArbiterEvmWallet>, ArbiterClientError> {
         todo!("fetch EVM wallet list from server")
     }
 }

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

@@ -5,8 +5,8 @@ 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")]
-pub use wallets::evm::ArbiterEvmWallet;
+pub use wallets::evm::{ArbiterEvmSignTransactionError, ArbiterEvmWallet};

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

@@ -1,18 +1,17 @@
-use arbiter_proto::proto::{
+use arbiter_proto::proto::client::{ClientRequest, ClientResponse};
-    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,
 
@@ -20,29 +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(
+    pub(crate) async fn recv(&mut self) -> Result<ClientResponse, ClientSignError> {
-        &mut self,
-    ) -> std::result::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

@@ -1,3 +1,21 @@
+use crate::transport::{ClientTransport, next_request_id};
+use arbiter_proto::proto::{
+    client::{
+        ClientRequest,
+        client_request::Payload as ClientRequestPayload,
+        client_response::Payload as ClientResponsePayload,
+        evm::{
+            self as proto_evm, request::Payload as EvmRequestPayload,
+            response::Payload as EvmResponsePayload,
+        },
+    },
+    evm::{
+        EvmSignTransactionRequest,
+        evm_sign_transaction_response::Result as EvmSignTransactionResult,
+    },
+    shared::evm::TransactionEvalError,
+};
+
 use alloy::{
     consensus::SignableTransaction,
     network::TxSigner,
@@ -8,7 +26,30 @@ use async_trait::async_trait;
 use std::sync::Arc;
 use tokio::sync::Mutex;
 
-use crate::transport::ClientTransport;
+/// A typed error payload returned by [`ArbiterEvmWallet`] transaction signing.
+///
+/// This is wrapped into `alloy::signers::Error::Other`, so consumers can downcast by [`TryFrom`] and
+/// interpret the concrete policy evaluation failure instead of parsing strings.
+#[derive(Debug, thiserror::Error)]
+#[non_exhaustive]
+pub enum ArbiterEvmSignTransactionError {
+    #[error("transaction rejected by policy: {0:?}")]
+    PolicyEval(TransactionEvalError),
+}
+
+impl<'a> TryFrom<&'a Error> for &'a ArbiterEvmSignTransactionError {
+    type Error = ();
+
+    fn try_from(value: &'a Error) -> Result<Self, Self::Error> {
+        if let Error::Other(inner) = value
+            && let Some(eval_error) = inner.downcast_ref()
+        {
+            Ok(eval_error)
+        } else {
+            Err(())
+        }
+    }
+}
 
 pub struct ArbiterEvmWallet {
     transport: Arc<Mutex<ClientTransport>>,
@@ -17,7 +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,
@@ -25,11 +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
     }
@@ -79,11 +125,73 @@ impl TxSigner<Signature> for ArbiterEvmWallet {
         &self,
         tx: &mut dyn SignableTransaction<Signature>,
     ) -> Result<Signature> {
-        let _transport = self.transport.lock().await;
         self.validate_chain_id(tx)?;
 
-        Err(Error::other(
+        let mut transport = self.transport.lock().await;
-            "transaction signing is not supported by current arbiter.client protocol",
+        let request_id = next_request_id();
-        ))
+        let rlp_transaction = tx.encoded_for_signing();
+
+        transport
+            .send(ClientRequest {
+                request_id,
+                payload: Some(ClientRequestPayload::Evm(proto_evm::Request {
+                    payload: Some(EvmRequestPayload::SignTransaction(
+                        EvmSignTransactionRequest {
+                            wallet_address: self.address.to_vec(),
+                            rlp_transaction,
+                        },
+                    )),
+                })),
+            })
+            .await
+            .map_err(|_| Error::other("failed to send evm sign transaction request"))?;
+
+        let response = transport
+            .recv()
+            .await
+            .map_err(|_| Error::other("failed to receive evm sign transaction response"))?;
+        drop(transport);
+
+        if response.request_id != Some(request_id) {
+            return Err(Error::other(
+                "received mismatched response id for evm sign transaction",
+            ));
+        }
+
+        let payload = response
+            .payload
+            .ok_or_else(|| Error::other("missing evm sign transaction response payload"))?;
+
+        let ClientResponsePayload::Evm(proto_evm::Response {
+            payload: Some(payload),
+        }) = payload
+        else {
+            return Err(Error::other(
+                "unexpected response payload for evm sign transaction request",
+            ));
+        };
+
+        let EvmResponsePayload::SignTransaction(response) = payload else {
+            return Err(Error::other(
+                "unexpected evm response payload for sign transaction request",
+            ));
+        };
+
+        let result = response
+            .result
+            .ok_or_else(|| Error::other("missing evm sign transaction result"))?;
+
+        match result {
+            EvmSignTransactionResult::Signature(signature) => {
+                Signature::try_from(signature.as_slice())
+                    .map_err(|_| Error::other("invalid signature returned by server"))
+            }
+            EvmSignTransactionResult::EvalError(eval_error) => Err(Error::other(
+                ArbiterEvmSignTransactionError::PolicyEval(eval_error),
+            )),
+            EvmSignTransactionResult::Error(code) => Err(Error::other(format!(
+                "server failed to sign transaction with error code {code}"
+            ))),
+        }
     }
 }

server/crates/arbiter-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/integrity.rs

@@ -0,0 +1,49 @@
+use crate::hashing::Hashable;
+
+/// Marks a struct as a participant in the database integrity system.
+///
+/// Implementors are protected by an HMAC-SHA256 MAC stored in the
+/// `integrity_envelope` table. The MAC is computed over:
+///
+/// ```text
+/// HMAC-SHA256(key, len(KIND) || KIND || len(entity_id) || entity_id || VERSION || SHA256(Hashable))
+/// ```
+///
+/// Both `KIND` and `VERSION` act as domain separators — they prevent a valid
+/// MAC for one entity type or schema version from being accepted for another.
+///
+/// # Deriving
+///
+/// Use `#[derive(Integrable)]` with the `#[integrable(kind = "...")]` attribute.
+/// `VERSION` is computed automatically as an FNV-1a hash of the struct's field
+/// names and types, so it changes whenever the schema changes without any manual
+/// bookkeeping.
+///
+/// ```rust,ignore
+/// #[derive(Hashable, Integrable)]
+/// #[integrable(kind = "operator_credentials")]
+/// pub struct OperatorCredentials {
+///     pub pubkey: PublicKey,
+/// }
+/// ```
+///
+/// # Upgrading schema
+///
+/// When fields are added, removed, or reordered, `VERSION` changes automatically.
+/// Existing MAC records in the database will return [`PayloadVersionMismatch`] on
+/// verification — this is the signal to re-sign all rows for this `KIND` as part
+/// of a migration.
+///
+/// [`PayloadVersionMismatch`]: crate::integrity::Integrable
+pub trait Integrable: Hashable {
+    /// Stable name of this entity type as stored in `integrity_envelope.entity_kind`.
+    ///
+    /// Must be a valid schema name: starts with a letter, contains only `[a-zA-Z0-9_]`,
+    /// and must be globally unique across all `Integrable` types in the system.
+    const KIND: &'static str;
+
+    /// FNV-1a hash of the struct's field names and types at the time the derive
+    /// macro ran. Changes automatically when the schema changes, invalidating
+    /// existing MACs and signalling that a migration is required.
+    const VERSION: i32;
+}

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

@@ -0,0 +1,8 @@
+#[cfg(feature = "authn")]
+pub mod authn;
+pub mod hashing;
+pub mod integrity;
+#[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 +1,20 @@
+[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" }
+trybuild = { version = "1.0", features = ["diff"] }
+
+[lints]
+workspace = true

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

@@ -0,0 +1,115 @@
+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) => crate::utils::sorted_named_fields(fields)
+            .into_iter()
+            .map(|field| {
+                let name = field.ident.as_ref().unwrap();
+                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/integrable.rs

@@ -0,0 +1,134 @@
+use crate::utils::INTEGRABLE_TRAIT_PATH;
+use proc_macro2::TokenStream;
+use quote::quote;
+use syn::{DeriveInput, LitStr, spanned::Spanned as _};
+
+struct IntegrableAttr {
+    kind: String,
+}
+
+impl IntegrableAttr {
+    fn from_attrs(
+        attrs: &[syn::Attribute],
+        ident_span: proc_macro2::Span,
+    ) -> Result<Self, syn::Error> {
+        let mut kind: Option<String> = None;
+        let mut found = false;
+
+        for attr in attrs {
+            if !attr.path().is_ident("integrable") {
+                continue;
+            }
+            if found {
+                return Err(syn::Error::new(attr.span(), "duplicate #[integrable] attribute"));
+            }
+            found = true;
+            attr.parse_nested_meta(|meta| {
+                if meta.path.is_ident("kind") {
+                    let lit: LitStr = meta.value()?.parse()?;
+                    let v = lit.value();
+                    if v.is_empty() {
+                        return Err(syn::Error::new(lit.span(), "kind must not be empty"));
+                    }
+                    if !is_valid_kind(&v) {
+                        return Err(syn::Error::new(
+                            lit.span(),
+                            "kind must be a valid schema name: start with a letter, contain only [a-zA-Z0-9_]",
+                        ));
+                    }
+                    kind = Some(v);
+                } else {
+                    return Err(meta.error("unknown key; expected `kind`"));
+                }
+                Ok(())
+            })?;
+        }
+
+        let kind = kind.ok_or_else(|| {
+            syn::Error::new(ident_span, "#[integrable(kind = \"...\")] is required")
+        })?;
+
+        Ok(Self { kind })
+    }
+}
+
+fn is_valid_kind(s: &str) -> bool {
+    let mut chars = s.chars();
+    matches!(chars.next(), Some(c) if c.is_ascii_alphabetic())
+        && chars.all(|c| c.is_ascii_alphanumeric() || c == '_')
+}
+
+fn fnv1a(data: &[u8], mut hash: u32) -> u32 {
+    const FNV_PRIME: u32 = 16_777_619;
+    for &b in data {
+        hash ^= u32::from(b);
+        hash = hash.wrapping_mul(FNV_PRIME);
+    }
+    hash
+}
+
+// Hashes field names and types using the same alphabetical sort order as Hashable,
+// so that source-level field reordering never changes VERSION.
+fn compute_version(fields: &syn::Fields) -> i32 {
+    const FNV_OFFSET: u32 = 2_166_136_261;
+    let mut hash = FNV_OFFSET;
+
+    match fields {
+        syn::Fields::Named(named) => {
+            for field in crate::utils::sorted_named_fields(named) {
+                let name = field.ident.as_ref().unwrap().to_string();
+                let ty = &field.ty;
+                hash = fnv1a(name.as_bytes(), hash);
+                hash = fnv1a(quote!(#ty).to_string().as_bytes(), hash);
+            }
+        }
+        syn::Fields::Unnamed(unnamed) => {
+            for (i, field) in unnamed.unnamed.iter().enumerate() {
+                let ty = &field.ty;
+                hash = fnv1a(i.to_string().as_bytes(), hash);
+                hash = fnv1a(quote!(#ty).to_string().as_bytes(), hash);
+            }
+        }
+        syn::Fields::Unit => {}
+    }
+
+    // Clear sign bit to guarantee a positive i32; substitute 0 → 1.
+    let v = (hash >> 1).cast_signed();
+    if v == 0 { 1 } else { v }
+}
+
+pub(crate) fn derive(input: &DeriveInput) -> TokenStream {
+    let syn::Data::Struct(ref data) = input.data else {
+        return syn::Error::new(
+            input.ident.span(),
+            "#[derive(Integrable)] is only supported on structs",
+        )
+        .to_compile_error();
+    };
+
+    let integrable_trait = INTEGRABLE_TRAIT_PATH.to_path();
+    let hashable_trait = crate::utils::HASHABLE_TRAIT_PATH.to_path();
+    let ident = &input.ident;
+
+    let mut generics = input.generics.clone();
+    for type_param in generics.type_params_mut() {
+        type_param.bounds.push(syn::parse_quote!(#hashable_trait));
+    }
+    let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
+
+    let attr = match IntegrableAttr::from_attrs(&input.attrs, input.ident.span()) {
+        Ok(a) => a,
+        Err(e) => return e.to_compile_error(),
+    };
+
+    let kind = attr.kind;
+    let version = compute_version(&data.fields);
+
+    quote! {
+        #[automatically_derived]
+        impl #impl_generics #integrable_trait for #ident #ty_generics #where_clause {
+            const KIND: &'static str = #kind;
+            const VERSION: i32 = #version;
+        }
+    }
+}

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

@@ -0,0 +1,17 @@
+use syn::{DeriveInput, parse_macro_input};
+
+mod hashable;
+mod integrable;
+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()
+}
+
+#[proc_macro_derive(Integrable, attributes(integrable))]
+pub fn derive_integrable(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let input = parse_macro_input!(input as DeriveInput);
+    integrable::derive(&input).into()
+}

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

@@ -0,0 +1,35 @@
+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);
+ensure_path!(::arbiter_crypto::integrity::Integrable as INTEGRABLE_TRAIT_PATH);
+
+/// Returns named struct fields sorted alphabetically by name.
+/// Both `Hashable` and `Integrable` derive macros must iterate fields in the
+/// same deterministic order so that source-level reordering never changes
+/// either the runtime hash or the compile-time VERSION.
+pub(crate) fn sorted_named_fields(fields: &syn::FieldsNamed) -> Vec<&syn::Field> {
+    let mut v: Vec<&syn::Field> = fields.named.iter().collect();
+    v.sort_by_key(|f| f.ident.as_ref().unwrap().to_string());
+    v
+}

server/crates/arbiter-macros/tests/integrable.rs

@@ -0,0 +1,53 @@
+use arbiter_crypto::integrity::Integrable;
+
+#[derive(arbiter_macros::Hashable, arbiter_macros::Integrable)]
+#[integrable(kind = "test_entity")]
+struct TestEntity {
+    value: i32,
+}
+
+#[derive(arbiter_macros::Hashable, arbiter_macros::Integrable)]
+#[integrable(kind = "other_entity")]
+struct OtherEntity {
+    label: String,
+    count: u64,
+}
+
+#[test]
+fn kind_is_set_correctly() {
+    assert_eq!(<TestEntity as Integrable>::KIND, "test_entity");
+    assert_eq!(<OtherEntity as Integrable>::KIND, "other_entity");
+}
+
+#[test]
+fn version_is_positive() {
+    const {
+        assert!(<TestEntity as Integrable>::VERSION > 0);
+        assert!(<OtherEntity as Integrable>::VERSION > 0);
+    }
+}
+
+#[test]
+fn different_field_layouts_produce_different_versions() {
+    assert_ne!(
+        <TestEntity as Integrable>::VERSION,
+        <OtherEntity as Integrable>::VERSION,
+    );
+}
+
+#[derive(arbiter_macros::Hashable, arbiter_macros::Integrable)]
+#[integrable(kind = "generic_entity")]
+struct GenericEntity<T> {
+    inner: T,
+}
+
+#[test]
+fn generic_struct_derives_integrable() {
+    assert_eq!(
+        <GenericEntity<TestEntity> as Integrable>::KIND,
+        "generic_entity"
+    );
+    const {
+        assert!(<GenericEntity<TestEntity> as Integrable>::VERSION > 0);
+    }
+}

server/crates/arbiter-macros/tests/integrable_errors.rs

@@ -0,0 +1,5 @@
+#[test]
+fn integrable_compile_fail() {
+    let t = trybuild::TestCases::new();
+    t.compile_fail("tests/ui/integrable/*.rs");
+}

server/crates/arbiter-macros/tests/ui/integrable/duplicate_attr.rs

@@ -0,0 +1,8 @@
+#[derive(arbiter_macros::Hashable, arbiter_macros::Integrable)]
+#[integrable(kind = "entity_a")]
+#[integrable(kind = "entity_b")]
+struct DuplicateAttr {
+    value: i32,
+}
+
+fn main() {}

server/crates/arbiter-macros/tests/ui/integrable/duplicate_attr.stderr

@@ -0,0 +1,5 @@
+error: duplicate #[integrable] attribute
+ --> tests/ui/integrable/duplicate_attr.rs:3:1
+  |
+3 | #[integrable(kind = "entity_b")]
+  | ^

server/crates/arbiter-macros/tests/ui/integrable/empty_kind.rs

@@ -0,0 +1,7 @@
+#[derive(arbiter_macros::Hashable, arbiter_macros::Integrable)]
+#[integrable(kind = "")]
+struct EmptyKind {
+    value: i32,
+}
+
+fn main() {}

server/crates/arbiter-macros/tests/ui/integrable/empty_kind.stderr

@@ -0,0 +1,5 @@
+error: kind must not be empty
+ --> tests/ui/integrable/empty_kind.rs:2:21
+  |
+2 | #[integrable(kind = "")]
+  |                     ^^

server/crates/arbiter-macros/tests/ui/integrable/enum_not_supported.rs

@@ -0,0 +1,8 @@
+#[derive(arbiter_macros::Integrable)]
+#[integrable(kind = "my_enum")]
+enum MyEnum {
+    A,
+    B,
+}
+
+fn main() {}

server/crates/arbiter-macros/tests/ui/integrable/enum_not_supported.stderr

@@ -0,0 +1,5 @@
+error: #[derive(Integrable)] is only supported on structs
+ --> tests/ui/integrable/enum_not_supported.rs:3:6
+  |
+3 | enum MyEnum {
+  |      ^^^^^^

server/crates/arbiter-macros/tests/ui/integrable/invalid_kind.rs

@@ -0,0 +1,7 @@
+#[derive(arbiter_macros::Hashable, arbiter_macros::Integrable)]
+#[integrable(kind = "bad kind!")]
+struct InvalidKind {
+    value: i32,
+}
+
+fn main() {}

server/crates/arbiter-macros/tests/ui/integrable/invalid_kind.stderr

@@ -0,0 +1,5 @@
+error: kind must be a valid schema name: start with a letter, contain only [a-zA-Z0-9_]
+ --> tests/ui/integrable/invalid_kind.rs:2:21
+  |
+2 | #[integrable(kind = "bad kind!")]
+  |                     ^^^^^^^^^^^

server/crates/arbiter-macros/tests/ui/integrable/missing_attr.rs

@@ -0,0 +1,6 @@
+#[derive(arbiter_macros::Hashable, arbiter_macros::Integrable)]
+struct MissingAttr {
+    value: i32,
+}
+
+fn main() {}

server/crates/arbiter-macros/tests/ui/integrable/missing_attr.stderr

@@ -0,0 +1,5 @@
+error: #[integrable(kind = "...")] is required
+ --> tests/ui/integrable/missing_attr.rs:2:8
+  |
+2 | struct MissingAttr {
+  |        ^^^^^^^^^^^

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

@@ -1,21 +1,59 @@
 pub mod transport;
 pub mod url;
 
-use base64::{Engine, prelude::BASE64_STANDARD};
-use std::{
-    path::PathBuf,
-    sync::{LazyLock, RwLock},
-};
-
 pub mod proto {
     tonic::include_proto!("arbiter");
 
-    pub mod user_agent {
+    pub mod shared {
-        tonic::include_proto!("arbiter.user_agent");
+        tonic::include_proto!("arbiter.shared");
+
+        pub mod evm {
+            tonic::include_proto!("arbiter.shared.evm");
+        }
+    }
+
+    pub mod operator {
+        tonic::include_proto!("arbiter.operator");
+
+        pub mod auth {
+            tonic::include_proto!("arbiter.operator.auth");
+        }
+
+        pub mod evm {
+            tonic::include_proto!("arbiter.operator.evm");
+        }
+
+        pub mod sdk_client {
+            tonic::include_proto!("arbiter.operator.sdk_client");
+        }
+
+        pub mod vault {
+            tonic::include_proto!("arbiter.operator.vault");
+
+            pub mod bootstrap {
+                tonic::include_proto!("arbiter.operator.vault.bootstrap");
+            }
+
+            pub mod unseal {
+                tonic::include_proto!("arbiter.operator.vault.unseal");
+            }
+        }
     }
 
     pub mod client {
         tonic::include_proto!("arbiter.client");
+
+        pub mod auth {
+            tonic::include_proto!("arbiter.client.auth");
+        }
+
+        pub mod evm {
+            tonic::include_proto!("arbiter.client.evm");
+        }
+
+        pub mod vault {
+            tonic::include_proto!("arbiter.client.vault");
+        }
     }
 
     pub mod evm {
@@ -31,27 +69,8 @@ pub struct ClientMetadata {
 }
 
 pub static BOOTSTRAP_PATH: &str = "bootstrap_token";
-pub const DEFAULT_SERVER_PORT: u16 = 50051;
-static HOME_OVERRIDE: LazyLock<RwLock<Option<PathBuf>>> = LazyLock::new(|| RwLock::new(None));
-
-pub fn set_home_path_override(path: Option<PathBuf>) -> Result<(), std::io::Error> {
-    let mut lock = HOME_OVERRIDE
-        .write()
-        .map_err(|_| std::io::Error::other("home path override lock poisoned"))?;
-    *lock = path;
-    Ok(())
-}
 
 pub fn home_path() -> Result<std::path::PathBuf, std::io::Error> {
-    if let Some(path) = HOME_OVERRIDE
-        .read()
-        .map_err(|_| std::io::Error::other("home path override lock poisoned"))?
-        .clone()
-    {
-        std::fs::create_dir_all(&path)?;
-        return Ok(path);
-    }
-
     static ARBITER_HOME: &str = ".arbiter";
     let home_dir = std::env::home_dir().ok_or(std::io::Error::new(
         std::io::ErrorKind::PermissionDenied,
@@ -63,8 +82,3 @@ 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

@@ -1,13 +1,11 @@
-use std::fmt::Display;
-
 use base64::{Engine as _, prelude::BASE64_URL_SAFE};
 use rustls_pki_types::CertificateDer;
+use std::fmt::Display;
 
 const ARBITER_URL_SCHEME: &str = "arbiter";
 const CERT_QUERY_KEY: &str = "cert";
 const BOOTSTRAP_TOKEN_QUERY_KEY: &str = "bootstrap_token";
 
-
 #[derive(Debug, Clone)]
 pub struct ArbiterUrl {
     pub host: String,
@@ -106,7 +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
@@ -25,39 +26,36 @@ tonic.features = ["tls-aws-lc"]
 tokio.workspace = true
 rustls.workspace = true
 smlang.workspace = true
-miette.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
 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"
-clap = { version = "4.6", features = ["derive"] }
+anyhow = "1.0.102"
+mutants.workspace = true
+subtle = "2.6.1"
+x25519-dalek.workspace = true
+k256.workspace = true
+kameo_actors.workspace = true
 
 [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
 
-[target.'cfg(windows)'.dependencies]
+[lib]
-windows-service = "0.8"
+doctest = false

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

@@ -43,15 +43,13 @@ create table if not exists arbiter_settings (
 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_client (
     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_client_public_key on operator_client (public_key);
 
 create table if not exists client_metadata (
     id integer not null primary key,
@@ -73,7 +71,6 @@ 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 +188,19 @@ 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

@@ -1,19 +1,20 @@
+use crate::db::{self, DatabasePool, schema};
 use arbiter_proto::{BOOTSTRAP_PATH, home_path};
+
 use diesel::QueryDsl;
 use diesel_async::RunQueryDsl;
 use kameo::{Actor, messages};
-use miette::Diagnostic;
 use rand::{RngExt, distr::Alphanumeric, make_rng, rngs::StdRng};
+use subtle::ConstantTimeEq as _;
 use thiserror::Error;
 
-use crate::db::{self, DatabasePool, schema};
 const TOKEN_LENGTH: usize = 64;
 
 pub async fn generate_token() -> Result<String, std::io::Error> {
     let rng: StdRng = make_rng();
 
-    let token: String = rng.sample_iter(Alphanumeric).take(TOKEN_LENGTH).fold(
+    let token = rng.sample_iter(Alphanumeric).take(TOKEN_LENGTH).fold(
-        Default::default(),
+        String::default(),
         |mut accum, char| {
             accum += char.to_string().as_str();
             accum
@@ -25,19 +26,16 @@ pub async fn generate_token() -> Result<String, std::io::Error> {
     Ok(token)
 }
 
-#[derive(Error, Debug, Diagnostic)]
+#[derive(Error, Debug)]
 pub enum Error {
     #[error("Database error: {0}")]
-    #[diagnostic(code(arbiter_server::bootstrap::database))]
     Database(#[from] db::PoolError),
 
-    #[error("Database query error: {0}")]
-    #[diagnostic(code(arbiter_server::bootstrap::database_query))]
-    Query(#[from] diesel::result::Error),
-
     #[error("I/O error: {0}")]
-    #[diagnostic(code(arbiter_server::bootstrap::io))]
     Io(#[from] std::io::Error),
+
+    #[error("Database query error: {0}")]
+    Query(#[from] diesel::result::Error),
 }
 
 #[derive(Actor)]
@@ -47,14 +45,14 @@ pub struct Bootstrapper {
 
 impl Bootstrapper {
     pub async fn new(db: &DatabasePool) -> Result<Self, Error> {
-        let mut conn = db.get().await?;
+        let row_count: i64 = {
+            let mut conn = db.get().await?;
 
-        let row_count: i64 = schema::useragent_client::table
+            schema::operator_client::table
-            .count()
+                .count()
-            .get_result(&mut conn)
+                .get_result(&mut conn)
-            .await?;
+                .await?
-
+        };
-        drop(conn);
 
         let token = if row_count == 0 {
             let token = generate_token().await?;
@@ -71,10 +69,13 @@ impl Bootstrapper {
 impl Bootstrapper {
     #[message]
     pub fn is_correct_token(&self, token: String) -> bool {
-        match &self.token {
+        self.token.as_ref().is_some_and(|expected| {
-            Some(expected) => *expected == token,
+            let expected_bytes = expected.as_bytes();
-            None => false,
+            let token_bytes = token.as_bytes();
-        }
+
+            let choice = expected_bytes.ct_eq(token_bytes);
+            bool::from(choice)
+        })
     }
 
     #[message]

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

@@ -1,333 +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| {
-        let pubkey_bytes = pubkey_bytes.clone();
-        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<VerifyingKey, 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(pubkey)
-}

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

@@ -1,72 +0,0 @@
-use kameo::{Actor, messages};
-use tracing::error;
-
-use crate::{
-    actors::{
-        GlobalActors, client::ClientConnection, flow_coordinator::RegisterClient,
-        keyholder::KeyHolderState,
-    },
-    db,
-};
-
-pub struct ClientSession {
-    props: ClientConnection,
-}
-
-impl ClientSession {
-    pub(crate) fn new(props: ClientConnection) -> Self {
-        Self { props }
-    }
-}
-
-#[messages]
-impl ClientSession {
-    #[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 = "client", "keyholder.query.failed");
-                return Err(Error::Internal);
-            }
-        };
-
-        Ok(vault_state)
-    }
-}
-
-impl Actor for ClientSession {
-    type Args = Self;
-
-    type Error = Error;
-
-    async fn on_start(
-        args: Self::Args,
-        this: kameo::prelude::ActorRef<Self>,
-    ) -> Result<Self, Self::Error> {
-        args.props
-            .actors
-            .flow_coordinator
-            .ask(RegisterClient { actor: this })
-            .await
-            .map_err(|_| Error::ConnectionRegistrationFailed)?;
-        Ok(args)
-    }
-}
-
-impl ClientSession {
-    pub fn new_test(db: db::DatabasePool, actors: GlobalActors) -> Self {
-        let props = ClientConnection::new(db, actors);
-        Self { props }
-    }
-}
-
-#[derive(Debug, thiserror::Error)]
-pub enum Error {
-    #[error("Connection registration failed")]
-    ConnectionRegistrationFailed,
-    #[error("Internal error")]
-    Internal,
-}

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

@@ -1,4 +1,24 @@
-use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
+use crate::{
+    actors::vault::{CreateNew, Decrypt, Vault},
+    crypto::integrity,
+    db::{
+        DatabaseError, DatabasePool,
+        models::{self},
+        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,
 };
@@ -6,83 +26,60 @@ use diesel_async::RunQueryDsl;
 use kameo::{Actor, actor::ActorRef, messages};
 use rand::{SeedableRng, rng, rngs::StdRng};
 
-use crate::{
-    actors::keyholder::{CreateNew, Decrypt, KeyHolder},
-    db::{
-        self, 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;
 
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
+#[derive(Debug, thiserror::Error)]
 pub enum SignTransactionError {
     #[error("Wallet not found")]
-    #[diagnostic(code(arbiter::evm::sign::wallet_not_found))]
     WalletNotFound,
 
     #[error("Database error: {0}")]
-    #[diagnostic(code(arbiter::evm::sign::database))]
     Database(#[from] DatabaseError),
 
-    #[error("Keyholder error: {0}")]
+    #[error("Vault error: {0}")]
-    #[diagnostic(code(arbiter::evm::sign::keyholder))]
+    Vault(#[from] crate::actors::vault::Error),
-    Keyholder(#[from] crate::actors::keyholder::Error),
 
-    #[error("Keyholder mailbox error")]
+    #[error("Vault mailbox error")]
-    #[diagnostic(code(arbiter::evm::sign::keyholder_send))]
+    VaultSend,
-    KeyholderSend,
 
     #[error("Signing error: {0}")]
-    #[diagnostic(code(arbiter::evm::sign::signing))]
     Signing(#[from] alloy::signers::Error),
 
     #[error("Policy error: {0}")]
-    #[diagnostic(code(arbiter::evm::sign::vet))]
     Vet(#[from] evm::VetError),
 }
 
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
+#[derive(Debug, thiserror::Error)]
 pub enum Error {
-    #[error("Keyholder error: {0}")]
+    #[error("Vault error: {0}")]
-    #[diagnostic(code(arbiter::evm::keyholder))]
+    Vault(#[from] crate::actors::vault::Error),
-    Keyholder(#[from] crate::actors::keyholder::Error),
 
-    #[error("Keyholder mailbox error")]
+    #[error("Vault mailbox error")]
-    #[diagnostic(code(arbiter::evm::keyholder_send))]
+    VaultSend,
-    KeyholderSend,
 
     #[error("Database error: {0}")]
-    #[diagnostic(code(arbiter::evm::database))]
     Database(#[from] DatabaseError),
+
+    #[error("Integrity violation: {0}")]
+    Integrity(#[from] integrity::Error),
 }
 
 #[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,
@@ -99,10 +96,10 @@ impl EvmActor {
         let plaintext = key_cell.read_inline(|reader| SafeCell::new(reader.to_vec()));
 
         let aead_id: i32 = self
-            .keyholder
+            .vault
             .ask(CreateNew { plaintext })
             .await
-            .map_err(|_| Error::KeyholderSend)?;
+            .map_err(|_| Error::VaultSend)?;
 
         let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
         let wallet_id = insert_into(schema::evm_wallet::table)
@@ -137,50 +134,49 @@ 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]
@@ -246,12 +242,12 @@ impl EvmActor {
         drop(conn);
 
         let raw_key: SafeCell<Vec<u8>> = self
-            .keyholder
+            .vault
             .ask(Decrypt {
                 aead_id: wallet.aead_encrypted_id,
             })
             .await
-            .map_err(|_| SignTransactionError::KeyholderSend)?;
+            .map_err(|_| SignTransactionError::VaultSend)?;
 
         let signer = safe_signer::SafeSigner::from_cell(raw_key)?;
 
@@ -259,7 +255,6 @@ impl EvmActor {
             .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 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,
@@ -39,18 +42,23 @@ impl Actor for ClientApprovalController {
     type Error = ();
 
     async fn on_start(
-        Args { client, mut user_agents, reply }: Self::Args,
+        Args {
+            client,
+            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(),
@@ -58,6 +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)
     }
 
@@ -67,10 +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));
         }
@@ -81,7 +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));
@@ -93,9 +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 +13,23 @@ 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>>,
+    operator_registry: ActorRef<OperatorRegistry>,
+}
+
+impl FlowCoordinator {
+    pub fn new(operator_registry: ActorRef<OperatorRegistry>) -> Self {
+        Self {
+            clients: HashMap::default(),
+            operator_registry,
+        }
+    }
 }
 
 impl Actor for FlowCoordinator {
@@ -38,13 +47,7 @@ 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!(
-                ?id,
-                actor = "FlowCoordinator",
-                event = "useragent.disconnected"
-            );
-        } else if self.clients.remove(&id).is_some() {
             info!(
                 ?id,
                 actor = "FlowCoordinator",
@@ -63,23 +66,12 @@ 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,
@@ -101,15 +93,19 @@ 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/mod.rs

@@ -1,50 +1,59 @@
-use kameo::actor::{ActorRef, Spawn};
-use miette::Diagnostic;
-use thiserror::Error;
-
 use crate::{
     actors::{
         bootstrap::Bootstrapper, evm::EvmActor, flow_coordinator::FlowCoordinator,
-        keyholder::KeyHolder,
+        operator_registry::OperatorRegistry, vault::Vault,
     },
     db,
 };
 
-pub mod bootstrap;
+use kameo::actor::{ActorRef, Spawn};
-pub mod client;
+use kameo_actors::{DeliveryStrategy, message_bus::MessageBus};
-mod evm;
+use thiserror::Error;
-pub mod flow_coordinator;
-pub mod keyholder;
-pub mod user_agent;
 
-#[derive(Error, Debug, Diagnostic)]
+pub mod bootstrap;
+pub mod evm;
+pub mod flow_coordinator;
+pub mod operator_registry;
+pub mod vault;
+
+#[derive(Error, Debug)]
 pub enum SpawnError {
     #[error("Failed to spawn Bootstrapper actor")]
-    #[diagnostic(code(SpawnError::Bootstrapper))]
     Bootstrapper(#[from] bootstrap::Error),
 
-    #[error("Failed to spawn KeyHolder actor")]
+    #[error("Failed to spawn Vault actor")]
-    #[diagnostic(code(SpawnError::KeyHolder))]
+    Vault(#[from] vault::Error),
-    KeyHolder(#[from] keyholder::Error),
 }
 
 /// Long-lived actors that are shared across all connections and handle global state and operations
 #[derive(Clone)]
 pub struct GlobalActors {
-    pub key_holder: ActorRef<KeyHolder>,
+    pub vault: ActorRef<Vault>,
     pub bootstrapper: ActorRef<Bootstrapper>,
     pub 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 message_bus = Self::spawn_message_bus();
+        let key_holder = Vault::spawn(Vault::new(db.clone(), message_bus.clone()).await?);
+        let operator_registry = OperatorRegistry::spawn(OperatorRegistry::default());
         Ok(Self {
             bootstrapper: Bootstrapper::spawn(Bootstrapper::new(&db).await?),
             evm: EvmActor::spawn(EvmActor::new(key_holder.clone(), db)),
-            key_holder,
+            vault: key_holder,
-            flow_coordinator: FlowCoordinator::spawn(FlowCoordinator::default()),
+            flow_coordinator: FlowCoordinator::spawn(FlowCoordinator::new(
+                operator_registry.clone(),
+            )),
+            operator_registry,
+            events: message_bus,
         })
     }
 }

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

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

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

@@ -1,222 +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 {
-            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

@@ -1,473 +0,0 @@
-use std::sync::Mutex;
-
-use alloy::primitives::Address;
-use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
-use diesel::sql_types::ops::Add;
-use diesel::{BoolExpressionMethods as _, ExpressionMethods as _, QueryDsl as _, SelectableHelper};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::error::SendError;
-use kameo::prelude::Context;
-use kameo::{message, messages};
-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::{
-    CoreEvmWalletAccess, EvmWalletAccess, NewEvmWalletAccess, ProgramClient, ProgramClientMetadata,
-};
-use crate::db::schema::evm_wallet_access;
-use crate::evm::policies::{Grant, SpecificGrant};
-use crate::safe_cell::SafeCell;
-use crate::{
-    actors::{
-        evm::{
-            Generate, ListWallets, 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),
-}
-
-#[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_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

@@ -1,85 +1,98 @@
+use crate::{
+    crypto::{
+        KeyCell, derive_key,
+        encryption::v1::{self, Nonce},
+        integrity::v1::HmacSha256,
+    },
+    db::{
+        self,
+        models::{self, RootKeyHistory},
+        schema::{self},
+    },
+};
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+
 use chrono::Utc;
 use diesel::{
     ExpressionMethods as _, OptionalExtension, QueryDsl, SelectableHelper,
     dsl::{insert_into, update},
 };
 use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::{Actor, Reply, messages};
+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};
 
-use crate::safe_cell::SafeCell;
+pub mod events {
-use crate::{
-    db::{
-        self,
-        models::{self, RootKeyHistory},
-        schema::{self},
-    },
-    safe_cell::SafeCellHandle as _,
-};
-use encryption::v1::{self, KeyCell, Nonce};
 
-pub mod encryption;
+    #[derive(Clone, Copy)]
+    pub struct Bootstrapped;
+
+    #[derive(Clone, Copy)]
+    pub struct Unsealed;
+
+    #[derive(Clone, Copy)]
+    pub struct VaultResealed;
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("Vault is already bootstrapped")]
+    AlreadyBootstrapped,
+    #[error("Vault is not bootstrapped")]
+    NotBootstrapped,
+    #[error("Vault is sealed")]
+    Sealed,
+    #[error("Invalid key provided")]
+    InvalidKey,
+
+    #[error("Requested aead entry not found")]
+    NotFound,
+
+    #[error("Encryption error: {0}")]
+    Encryption(#[from] chacha20poly1305::aead::Error),
+
+    #[error("Database error: {0}")]
+    DatabaseConnection(#[from] db::PoolError),
+
+    #[error("Database transaction error: {0}")]
+    DatabaseTransaction(#[from] diesel::result::Error),
+
+    #[error("Broken database")]
+    BrokenDatabase,
+}
+
+struct Unsealed {
+    root_key_history_id: i32,
+    root_key: KeyCell,
+}
 
 #[derive(Default, EnumDiscriminants)]
-#[strum_discriminants(derive(Reply), vis(pub), name(KeyHolderState))]
+#[strum_discriminants(derive(Reply), vis(pub), name(VaultState))]
 enum State {
     #[default]
     Unbootstrapped,
     Sealed {
         root_key_history_id: i32,
     },
-    Unsealed {
+    Unsealed(Unsealed),
-        root_key_history_id: i32,
-        root_key: KeyCell,
-    },
-}
-
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
-pub enum Error {
-    #[error("Keyholder is already bootstrapped")]
-    #[diagnostic(code(arbiter::keyholder::already_bootstrapped))]
-    AlreadyBootstrapped,
-    #[error("Keyholder is not bootstrapped")]
-    #[diagnostic(code(arbiter::keyholder::not_bootstrapped))]
-    NotBootstrapped,
-    #[error("Invalid key provided")]
-    #[diagnostic(code(arbiter::keyholder::invalid_key))]
-    InvalidKey,
-
-    #[error("Requested aead entry not found")]
-    #[diagnostic(code(arbiter::keyholder::aead_not_found))]
-    NotFound,
-
-    #[error("Encryption error: {0}")]
-    #[diagnostic(code(arbiter::keyholder::encryption_error))]
-    Encryption(#[from] chacha20poly1305::aead::Error),
-
-    #[error("Database error: {0}")]
-    #[diagnostic(code(arbiter::keyholder::database_error))]
-    DatabaseConnection(#[from] db::PoolError),
-
-    #[error("Database transaction error: {0}")]
-    #[diagnostic(code(arbiter::keyholder::database_transaction_error))]
-    DatabaseTransaction(#[from] diesel::result::Error),
-
-    #[error("Broken database")]
-    #[diagnostic(code(arbiter::keyholder::broken_database))]
-    BrokenDatabase,
 }
 
 /// Manages vault root key and tracks current state of the vault (bootstrapped/unbootstrapped, sealed/unsealed).
+///
 /// Provides API for encrypting and decrypting data using the vault root key.
 /// Abstraction over database to make sure nonces are never reused and encryption keys are never exposed in plaintext outside of this actor.
 #[derive(Actor)]
-pub struct KeyHolder {
+pub struct Vault {
     db: db::DatabasePool,
     state: State,
+    events: ActorRef<MessageBus>,
 }
 
 #[messages]
-impl KeyHolder {
+impl Vault {
-    pub async fn new(db: db::DatabasePool) -> Result<Self, Error> {
+    pub async fn new(db: db::DatabasePool, events: ActorRef<MessageBus>) -> Result<Self, Error> {
         let state = {
             let mut conn = db.get().await?;
 
@@ -97,59 +110,64 @@ impl KeyHolder {
             }
         };
 
-        Ok(Self { db, state })
+        Ok(Self { db, state, events })
     }
 
-    // Exclusive transaction to avoid race condtions if multiple keyholders write
+    // 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: i32) -> Result<Nonce, Error> {
         let mut conn = pool.get().await?;
 
         let nonce = conn
-            .exclusive_transaction(|conn| {
+            .exclusive_transaction(async |conn| {
-                Box::pin(async move {
+                let current_nonce: Vec<u8> = schema::root_key_history::table
-                    let current_nonce: Vec<u8> = schema::root_key_history::table
+                    .filter(schema::root_key_history::id.eq(root_key_id))
-                        .filter(schema::root_key_history::id.eq(root_key_id))
+                    .select(schema::root_key_history::data_encryption_nonce)
-                        .select(schema::root_key_history::data_encryption_nonce)
+                    .first(&mut *conn)
-                        .first(conn)
+                    .await?;
-                        .await?;
 
-                    let mut nonce =
+                let mut nonce = Nonce::try_from(current_nonce.as_slice()).map_err(|()| {
-                        v1::Nonce::try_from(current_nonce.as_slice()).map_err(|_| {
+                    error!(
-                            error!(
+                        "Broken database: invalid nonce for root key history id={}",
-                                "Broken database: invalid nonce for root key history id={}",
+                        root_key_id
-                                root_key_id
+                    );
-                            );
+                    Error::BrokenDatabase
-                            Error::BrokenDatabase
+                })?;
-                        })?;
+                nonce.increment();
-                    nonce.increment();
 
-                    update(schema::root_key_history::table)
+                update(schema::root_key_history::table)
-                        .filter(schema::root_key_history::id.eq(root_key_id))
+                    .filter(schema::root_key_history::id.eq(root_key_id))
-                        .set(schema::root_key_history::data_encryption_nonce.eq(nonce.to_vec()))
+                    .set(schema::root_key_history::data_encryption_nonce.eq(nonce.to_vec()))
-                        .execute(conn)
+                    .execute(&mut *conn)
-                        .await?;
+                    .await?;
 
-                    Result::<_, Error>::Ok(nonce)
+                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),
+        }
+    }
+
     #[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 seal_key = derive_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 root_key_nonce = Nonce::default();
-        let data_encryption_nonce = v1::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();
@@ -165,37 +183,36 @@ impl KeyHolder {
 
         let data_encryption_nonce_bytes = data_encryption_nonce.to_vec();
         let root_key_history_id = conn
-            .transaction(|conn| {
+            .transaction(async |conn| {
-                Box::pin(async move {
+                let root_key_history_id: i32 = insert_into(schema::root_key_history::table)
-                    let root_key_history_id: i32 = insert_into(schema::root_key_history::table)
+                    .values(&models::NewRootKeyHistory {
-                        .values(&models::NewRootKeyHistory {
+                        ciphertext: root_key_ciphertext.clone(),
-                            ciphertext: root_key_ciphertext,
+                        tag: v1::ROOT_KEY_TAG.to_vec(),
-                            tag: v1::ROOT_KEY_TAG.to_vec(),
+                        root_key_encryption_nonce: root_key_nonce.to_vec(),
-                            root_key_encryption_nonce: root_key_nonce.to_vec(),
+                        data_encryption_nonce: data_encryption_nonce_bytes.clone(),
-                            data_encryption_nonce: data_encryption_nonce_bytes,
+                        schema_version: 1,
-                            schema_version: 1,
+                        salt: salt.to_vec(),
-                            salt: salt.to_vec(),
+                    })
-                        })
+                    .returning(schema::root_key_history::id)
-                        .returning(schema::root_key_history::id)
+                    .get_result(&mut *conn)
-                        .get_result(conn)
+                    .await?;
-                        .await?;
 
-                    update(schema::arbiter_settings::table)
+                update(schema::arbiter_settings::table)
-                        .set(schema::arbiter_settings::root_key_id.eq(root_key_history_id))
+                    .set(schema::arbiter_settings::root_key_id.eq(root_key_history_id))
-                        .execute(conn)
+                    .execute(&mut *conn)
-                        .await?;
+                    .await?;
 
-                    Result::<_, diesel::result::Error>::Ok(root_key_history_id)
+                Result::<_, diesel::result::Error>::Ok(root_key_history_id)
-                })
             })
             .await?;
 
-        self.state = State::Unsealed {
+        self.state = State::Unsealed(Unsealed {
             root_key,
             root_key_history_id,
-        };
+        });
 
-        info!("Keyholder bootstrapped successfully");
+        info!("Vault bootstrapped successfully");
+        let _ = self.events.tell(Publish(events::Bootstrapped)).await;
 
         Ok(())
     }
@@ -214,7 +231,6 @@ impl KeyHolder {
             let mut conn = self.db.get().await?;
             schema::root_key_history::table
                 .filter(schema::root_key_history::id.eq(*root_key_history_id))
-                .select(schema::root_key_history::data_encryption_nonce)
                 .select(RootKeyHistory::as_select())
                 .first(&mut conn)
                 .await?
@@ -225,16 +241,15 @@ impl KeyHolder {
             error!("Broken database: invalid salt for root key");
             Error::BrokenDatabase
         })?;
-        let mut seal_key = v1::derive_seal_key(seal_key_raw, &salt);
+        let mut seal_key = derive_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(
+        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
-            },
+            })?;
-        )?;
 
         seal_key
             .decrypt_in_place(&nonce, v1::ROOT_KEY_TAG, &mut root_key)
@@ -243,25 +258,23 @@ impl KeyHolder {
                 Error::InvalidKey
             })?;
 
-        self.state = State::Unsealed {
+        self.state = State::Unsealed(Unsealed {
             root_key_history_id: current_key.id,
-            root_key: v1::KeyCell::try_from(root_key).map_err(|err| {
+            root_key: KeyCell::try_from(root_key).map_err(|err| {
                 error!(?err, "Broken database: invalid encryption key size");
                 Error::BrokenDatabase
             })?,
-        };
+        });
 
-        info!("Keyholder unsealed successfully");
+        info!("Vault unsealed successfully");
+        let _ = self.events.tell(Publish(events::Unsealed)).await;
 
         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 {
+        let Unsealed { root_key, .. } = Self::expect_unsealed(&mut self.state)?;
-            return Err(Error::NotBootstrapped);
-        };
 
         let row: models::AeadEncrypted = {
             let mut conn = self.db.get().await?;
@@ -274,7 +287,7 @@ impl KeyHolder {
                 .ok_or(Error::NotFound)?
         };
 
-        let nonce = v1::Nonce::try_from(row.current_nonce.as_slice()).map_err(|_| {
+        let nonce = Nonce::try_from(row.current_nonce.as_slice()).map_err(|()| {
             error!(
                 "Broken database: invalid nonce for aead_encrypted id={}",
                 aead_id
@@ -289,13 +302,10 @@ impl KeyHolder {
     // 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 {
+        let Unsealed {
             root_key,
             root_key_history_id,
-        } = &mut self.state
+        } = Self::expect_unsealed(&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
@@ -325,41 +335,80 @@ impl KeyHolder {
     }
 
     #[message]
-    pub fn get_state(&self) -> KeyHolderState {
+    pub fn get_state(&self) -> VaultState {
         self.state.discriminant()
     }
 
     #[message]
-    pub fn seal(&mut self) -> Result<(), Error> {
+    pub fn sign_integrity(&mut self, mac_input: Vec<u8>) -> Result<(i32, Vec<u8>), Error> {
-        let State::Unsealed {
+        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_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: i32,
+    ) -> Result<bool, Error> {
+        let Unsealed {
+            root_key,
+            root_key_history_id,
+        } = Self::expect_unsealed(&mut self.state)?;
+
+        if *root_key_history_id != key_version {
+            return Ok(false);
+        }
+
+        let mut hmac = root_key.0.read_inline(|k| {
+            HmacSha256::new_from_slice(k)
+                .unwrap_or_else(|_| unreachable!("HMAC accepts keys of any size"))
+        });
+        hmac.update(&key_version.to_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.state
+        } = Self::expect_unsealed(&mut self.state)?;
-        else {
+
-            return Err(Error::NotBootstrapped);
-        };
         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 diesel::SelectableHelper;
+    use crate::actors::GlobalActors;
-
+    use arbiter_crypto::safecell::SafeCellHandle as _;
-    use diesel_async::RunQueryDsl;
-
-    use crate::{
-        db::{self},
-        safe_cell::SafeCell,
-    };
 
     use super::*;
 
-    async fn bootstrapped_actor(db: &db::DatabasePool) -> KeyHolder {
+    async fn bootstrapped_actor(db: &db::DatabasePool) -> Vault {
-        let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+        let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+            .await
+            .unwrap();
         let seal_key = SafeCell::new(b"test-seal-key".to_vec());
         actor.bootstrap(seal_key).await.unwrap();
         actor
@@ -370,25 +419,26 @@ mod tests {
     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 {
+        let State::Unsealed(Unsealed {
-                root_key_history_id,
+            root_key_history_id,
-                ..
+            ..
-            } => root_key_history_id,
+        }) = actor.state
-            _ => panic!("expected unsealed state"),
+        else {
+            panic!("expected unsealed state")
         };
 
-        let n1 = KeyHolder::get_new_nonce(&db, root_key_history_id)
+        let n1 = Vault::get_new_nonce(&db, root_key_history_id)
             .await
             .unwrap();
-        let n2 = KeyHolder::get_new_nonce(&db, root_key_history_id)
+        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: models::RootKeyHistory = schema::root_key_history::table
+        let root_row: RootKeyHistory = schema::root_key_history::table
-            .select(models::RootKeyHistory::as_select())
+            .select(RootKeyHistory::as_select())
             .first(&mut conn)
             .await
             .unwrap();

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

@@ -1,72 +0,0 @@
-use std::{
-    net::{Ipv4Addr, SocketAddr, SocketAddrV4},
-    path::PathBuf,
-};
-
-use clap::{Args, Parser, Subcommand};
-
-const DEFAULT_LISTEN_ADDR: SocketAddr = SocketAddr::V4(SocketAddrV4::new(
-    Ipv4Addr::LOCALHOST,
-    arbiter_proto::DEFAULT_SERVER_PORT,
-));
-
-#[derive(Debug, Parser)]
-#[command(name = "arbiter-server")]
-#[command(about = "Arbiter gRPC server")]
-pub struct Cli {
-    #[command(subcommand)]
-    pub command: Option<Command>,
-}
-
-#[derive(Debug, Subcommand)]
-pub enum Command {
-    /// Run server in foreground mode.
-    Run(RunArgs),
-    /// Manage service lifecycle.
-    Service {
-        #[command(subcommand)]
-        command: ServiceCommand,
-    },
-}
-
-#[derive(Debug, Clone, Args)]
-pub struct RunArgs {
-    #[arg(long, default_value_t = DEFAULT_LISTEN_ADDR)]
-    pub listen_addr: SocketAddr,
-    #[arg(long)]
-    pub data_dir: Option<PathBuf>,
-}
-
-impl Default for RunArgs {
-    fn default() -> Self {
-        Self {
-            listen_addr: DEFAULT_LISTEN_ADDR,
-            data_dir: None,
-        }
-    }
-}
-
-#[derive(Debug, Subcommand)]
-pub enum ServiceCommand {
-    /// Install Windows service in Service Control Manager.
-    Install(ServiceInstallArgs),
-    /// Internal service entrypoint. SCM only.
-    #[command(hide = true)]
-    Run(ServiceRunArgs),
-}
-
-#[derive(Debug, Clone, Args)]
-pub struct ServiceInstallArgs {
-    #[arg(long)]
-    pub start: bool,
-    #[arg(long)]
-    pub data_dir: Option<PathBuf>,
-}
-
-#[derive(Debug, Clone, Args)]
-pub struct ServiceRunArgs {
-    #[arg(long, default_value_t = DEFAULT_LISTEN_ADDR)]
-    pub listen_addr: SocketAddr,
-    #[arg(long)]
-    pub data_dir: Option<PathBuf>,
-}

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

@@ -1,53 +1,45 @@
-use std::sync::Arc;
-
-use miette::Diagnostic;
-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, Diagnostic)]
+#[derive(Error, Debug)]
 pub enum InitError {
     #[error("Database setup failed: {0}")]
-    #[diagnostic(code(arbiter_server::init::database_setup))]
     DatabaseSetup(#[from] db::DatabaseSetupError),
 
     #[error("Connection acquire failed: {0}")]
-    #[diagnostic(code(arbiter_server::init::database_pool))]
     DatabasePool(#[from] db::PoolError),
 
     #[error("Database query error: {0}")]
-    #[diagnostic(code(arbiter_server::init::database_query))]
     DatabaseQuery(#[from] diesel::result::Error),
 
     #[error("TLS initialization failed: {0}")]
-    #[diagnostic(code(arbiter_server::init::tls_init))]
     Tls(#[from] tls::InitError),
 
     #[error("Actor spawn failed: {0}")]
-    #[diagnostic(code(arbiter_server::init::actor_spawn))]
     ActorSpawn(#[from] crate::actors::SpawnError),
 
     #[error("I/O Error: {0}")]
-    #[diagnostic(code(arbiter_server::init::io))]
     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
@@ -56,7 +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, string::FromUtf8Error};
-
-use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper as _};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-use miette::Diagnostic;
-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},
@@ -21,48 +7,58 @@ 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)
 };
 
-#[derive(Error, Debug, Diagnostic)]
+#[derive(Error, Debug)]
 pub enum InitError {
     #[error("Key generation error during TLS initialization: {0}")]
-    #[diagnostic(code(arbiter_server::tls_init::key_generation))]
     KeyGeneration(#[from] rcgen::Error),
 
     #[error("Key invalid format: {0}")]
-    #[diagnostic(code(arbiter_server::tls_init::key_invalid_format))]
     KeyInvalidFormat(#[from] FromUtf8Error),
 
     #[error("Key deserialization error: {0}")]
-    #[diagnostic(code(arbiter_server::tls_init::key_deserialization))]
     KeyDeserializationError(rcgen::Error),
 
     #[error("Database error during TLS initialization: {0}")]
-    #[diagnostic(code(arbiter_server::tls_init::database_error))]
     DatabaseError(#[from] diesel::result::Error),
 
     #[error("Pem deserialization error during TLS initialization: {0}")]
-    #[diagnostic(code(arbiter_server::tls_init::pem_deserialization))]
     PemDeserializationError(#[from] rustls::pki_types::pem::Error),
 
     #[error("Database pool acquire error during TLS initialization: {0}")]
-    #[diagnostic(code(arbiter_server::tls_init::database_pool_acquire))]
     DatabasePoolAcquire(#[from] db::PoolError),
 }
 
 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,
@@ -91,7 +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"
         )]
@@ -116,9 +112,7 @@ impl TlsCa {
         ];
         params
             .subject_alt_names
-            .push(SanType::IpAddress(IpAddr::from([
+            .push(SanType::IpAddress(Ipv4Addr::LOCALHOST.into()));
-                127, 0, 0, 1,
-            ])));
 
         let mut dn = DistinguishedName::new();
         dn.push(DnType::CommonName, "Arbiter Instance Leaf");
@@ -132,7 +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 {
@@ -141,7 +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)?;
@@ -173,28 +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?;
         }
@@ -242,10 +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 +1,102 @@
+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 password = SafeCell::new(PASSWORD.to_vec());
+        let password2 = SafeCell::new(PASSWORD.to_vec());
+        let salt = generate_salt();
+
+        let mut key1 = derive_key(password, &salt);
+        let mut key2 = derive_key(password2, &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 password = SafeCell::new(PASSWORD.to_vec());
+        let salt = generate_salt();
+
+        let mut key = derive_key(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 +1,329 @@
+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 use arbiter_crypto::integrity::Integrable;
+
+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)) => 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 diesel::{ExpressionMethods as _, QueryDsl};
+    use diesel_async::RunQueryDsl;
+    use kameo::{actor::ActorRef, prelude::Spawn};
+
+    use crate::{
+        actors::{
+            GlobalActors,
+            vault::{Bootstrap, Vault},
+        },
+        db::{self, schema},
+    };
+    use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+
+    use super::{Error, sign_entity, verify_entity};
+    #[derive(Clone, arbiter_macros::Hashable, arbiter_macros::Integrable)]
+    #[integrable(kind = "dummy_entity")]
+    struct DummyEntity {
+        payload_version: i32,
+        payload: Vec<u8>,
+    }
+
+    async fn bootstrapped_vault(db: &db::DatabasePool) -> ActorRef<Vault> {
+        let actor = Vault::spawn(
+            Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+                .await
+                .unwrap(),
+        );
+        actor
+            .ask(Bootstrap {
+                seal_key_raw: SafeCell::new(b"integrity-test-seal-key".to_vec()),
+            })
+            .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 { .. }));
+    }
+}

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

@@ -0,0 +1,155 @@
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use encryption::v1::{Nonce, Salt};
+
+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 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| {
+            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 the password using Argon2id, which is designed for password hashing and key derivation.
+pub fn derive_key(mut password: SafeCell<Vec<u8>>, salt: &Salt) -> 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 password = SafeCell::new(PASSWORD.to_vec());
+        let salt = generate_salt();
+
+        let mut key = derive_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");
+    }
+}