refactor(server): rewrote cell access using new helpers and added ast-grep rules for it

AGENTS.md

@@ -0,0 +1,128 @@
+# AGENTS.md
+
+This file provides guidance to Codex (Codex.ai/code) when working with code in this repository.
+
+## Project Overview
+
+Arbiter is a **permissioned signing service** for cryptocurrency wallets. It consists of:
+- **`server/`** — Rust gRPC daemon that holds encrypted keys and enforces policies
+- **`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.
+- **`MessageRouter`** — Coordinates streaming messages 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.

CLAUDE.md

@@ -0,0 +1,128 @@
+# CLAUDE.md
+
+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.
+- **`MessageRouter`** — Coordinates streaming messages 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.

mise.lock

@@ -1,3 +1,12 @@
+[[tools.ast-grep]]
+version = "0.42.0"
+backend = "aqua:ast-grep/ast-grep"
+"platforms.linux-arm64" = { checksum = "sha256:5c830eae8456569e2f7212434ed9c238f58dca412d76045418ed6d394a755836", url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-aarch64-unknown-linux-gnu.zip"}
+"platforms.linux-x64" = { checksum = "sha256:e825a05603f0bcc4cd9076c4cc8c9abd6d008b7cd07d9aa3cc323ba4b8606651", url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-x86_64-unknown-linux-gnu.zip"}
+"platforms.macos-arm64" = { checksum = "sha256:fc300d5293b1c770a5aece03a8a193b92e71e87cec726c28096990691a582620", url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-aarch64-apple-darwin.zip"}
+"platforms.macos-x64" = { checksum = "sha256:979ffe611327056f4730a1ae71b0209b3b830f58b22c6ed194cda34f55400db2", url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-x86_64-apple-darwin.zip"}
+"platforms.windows-x64" = { checksum = "sha256:55836fa1b2c65dc7d61615a4d9368622a0d2371a76d28b9a165e5a3ab6ae32a4", url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-x86_64-pc-windows-msvc.zip"}
+
 [[tools."cargo:cargo-audit"]]
 version = "0.22.1"
 backend = "cargo:cargo-audit"
@@ -42,6 +51,10 @@ backend = "cargo:diesel_cli"
 default-features = "false"
 features = "sqlite,sqlite-bundled"
 
+[[tools."cargo:rinf_cli"]]
+version = "8.9.1"
+backend = "cargo:rinf_cli"
+
 [[tools.flutter]]
 version = "3.38.9-stable"
 backend = "asdf:flutter"

mise.toml

@@ -10,3 +10,12 @@ protoc = "29.6"
 "cargo:cargo-shear" = "latest"
 "cargo:cargo-insta" = "1.46.3"
 python = "3.14.3"
+ast-grep = "0.42.0"
+
+[tasks.codegen]
+sources = ['protobufs/*.proto']
+outputs = ['useragent/lib/proto/*']
+run = '''
+dart pub global activate protoc_plugin && \
+protoc --dart_out=grpc:useragent/lib/proto --proto_path=protobufs/ protobufs/*.proto
+'''

protobufs/client.proto

@@ -23,7 +23,6 @@ message ClientRequest {
   oneof payload {
     AuthChallengeRequest auth_challenge_request = 1;
     AuthChallengeSolution auth_challenge_solution = 2;
-    arbiter.evm.EvmSignTransactionRequest evm_sign_transaction = 3;
   }
 }
 

protobufs/user_agent.proto

@@ -12,55 +12,6 @@ enum KeyType {
   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 SdkClientApproveRequest {
-  bytes pubkey = 1; // 32-byte ed25519 public key
-}
-
-message SdkClientRevokeRequest {
-  int32 client_id = 1;
-}
-
-message SdkClientEntry {
-  int32 id = 1;
-  bytes pubkey = 2;
-  int32 created_at = 3;
-}
-
-message SdkClientList {
-  repeated SdkClientEntry clients = 1;
-}
-
-message SdkClientApproveResponse {
-  oneof result {
-    SdkClientEntry client = 1;
-    SdkClientError error = 2;
-  }
-}
-
-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;
@@ -91,6 +42,12 @@ message UnsealEncryptedKey {
   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;
@@ -98,6 +55,13 @@ enum UnsealResult {
   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;
@@ -106,6 +70,16 @@ enum VaultState {
   VAULT_STATE_ERROR = 4;
 }
 
+message ClientConnectionRequest {
+  bytes pubkey = 1;
+}
+
+message ClientConnectionResponse {
+  bool approved = 1;
+}
+
+message ClientConnectionCancel {}
+
 message UserAgentRequest {
   oneof payload {
     AuthChallengeRequest auth_challenge_request = 1;
@@ -118,10 +92,8 @@ message UserAgentRequest {
     arbiter.evm.EvmGrantCreateRequest evm_grant_create = 8;
     arbiter.evm.EvmGrantDeleteRequest evm_grant_delete = 9;
     arbiter.evm.EvmGrantListRequest evm_grant_list = 10;
-    // field 11 reserved: was client_connection_response (online approval removed)
+    ClientConnectionResponse client_connection_response = 11;
-    SdkClientApproveRequest sdk_client_approve = 12;
+    BootstrapEncryptedKey bootstrap_encrypted_key = 12;
-    SdkClientRevokeRequest sdk_client_revoke = 13;
-    google.protobuf.Empty sdk_client_list = 14;
   }
 }
 message UserAgentResponse {
@@ -136,9 +108,8 @@ message UserAgentResponse {
     arbiter.evm.EvmGrantCreateResponse evm_grant_create = 8;
     arbiter.evm.EvmGrantDeleteResponse evm_grant_delete = 9;
     arbiter.evm.EvmGrantListResponse evm_grant_list = 10;
-    // fields 11, 12 reserved: were client_connection_request, client_connection_cancel (online approval removed)
+    ClientConnectionRequest client_connection_request = 11;
-    SdkClientApproveResponse sdk_client_approve = 13;
+    ClientConnectionCancel client_connection_cancel = 12;
-    SdkClientRevokeResponse sdk_client_revoke = 14;
+    BootstrapResult bootstrap_result = 13;
-    SdkClientListResponse sdk_client_list = 15;
   }
 }

server/Cargo.lock

@@ -678,18 +678,6 @@ checksum = "7f202df86484c868dbad7eaa557ef785d5c66295e41b460ef922eca0723b842c"
 [[package]]
 name = "arbiter-client"
 version = "0.1.0"
-dependencies = [
- "alloy",
- "arbiter-proto",
- "async-trait",
- "ed25519-dalek",
- "http",
- "rustls-webpki",
- "thiserror",
- "tokio",
- "tokio-stream",
- "tonic",
-]
 
 [[package]]
 name = "arbiter-proto"
@@ -703,7 +691,6 @@ dependencies = [
  "miette",
  "prost",
  "prost-types",
- "protoc-bin-vendored",
  "rand 0.10.0",
  "rcgen",
  "rstest",
@@ -740,6 +727,7 @@ dependencies = [
  "memsafe",
  "miette",
  "pem",
+ "prost-types",
  "rand 0.10.0",
  "rcgen",
  "restructed",
@@ -761,13 +749,6 @@ dependencies = [
  "zeroize",
 ]
 
-[[package]]
-name = "arbiter-terrors-poc"
-version = "0.1.0"
-dependencies = [
- "terrors",
-]
-
 [[package]]
 name = "arbiter-tokens-registry"
 version = "0.1.0"
@@ -775,30 +756,6 @@ dependencies = [
  "alloy",
 ]
 
-[[package]]
-name = "arbiter-useragent"
-version = "0.1.0"
-dependencies = [
- "arbiter-proto",
- "async-trait",
- "ed25519-dalek",
- "http",
- "k256",
- "kameo",
- "rand 0.10.0",
- "rsa",
- "rustls-webpki",
- "sha2 0.10.9",
- "smlang",
- "spki",
- "thiserror",
- "tokio",
- "tokio-stream",
- "tonic",
- "tracing",
- "x25519-dalek",
-]
-
 [[package]]
 name = "argon2"
 version = "0.5.3"
@@ -3680,70 +3637,6 @@ dependencies = [
  "prost",
 ]
 
-[[package]]
-name = "protoc-bin-vendored"
-version = "3.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d1c381df33c98266b5f08186583660090a4ffa0889e76c7e9a5e175f645a67fa"
-dependencies = [
- "protoc-bin-vendored-linux-aarch_64",
- "protoc-bin-vendored-linux-ppcle_64",
- "protoc-bin-vendored-linux-s390_64",
- "protoc-bin-vendored-linux-x86_32",
- "protoc-bin-vendored-linux-x86_64",
- "protoc-bin-vendored-macos-aarch_64",
- "protoc-bin-vendored-macos-x86_64",
- "protoc-bin-vendored-win32",
-]
-
-[[package]]
-name = "protoc-bin-vendored-linux-aarch_64"
-version = "3.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c350df4d49b5b9e3ca79f7e646fde2377b199e13cfa87320308397e1f37e1a4c"
-
-[[package]]
-name = "protoc-bin-vendored-linux-ppcle_64"
-version = "3.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a55a63e6c7244f19b5c6393f025017eb5d793fd5467823a099740a7a4222440c"
-
-[[package]]
-name = "protoc-bin-vendored-linux-s390_64"
-version = "3.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1dba5565db4288e935d5330a07c264a4ee8e4a5b4a4e6f4e83fad824cc32f3b0"
-
-[[package]]
-name = "protoc-bin-vendored-linux-x86_32"
-version = "3.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8854774b24ee28b7868cd71dccaae8e02a2365e67a4a87a6cd11ee6cdbdf9cf5"
-
-[[package]]
-name = "protoc-bin-vendored-linux-x86_64"
-version = "3.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b38b07546580df720fa464ce124c4b03630a6fb83e05c336fea2a241df7e5d78"
-
-[[package]]
-name = "protoc-bin-vendored-macos-aarch_64"
-version = "3.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "89278a9926ce312e51f1d999fee8825d324d603213344a9a706daa009f1d8092"
-
-[[package]]
-name = "protoc-bin-vendored-macos-x86_64"
-version = "3.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "81745feda7ccfb9471d7a4de888f0652e806d5795b61480605d4943176299756"
-
-[[package]]
-name = "protoc-bin-vendored-win32"
-version = "3.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "95067976aca6421a523e491fce939a3e65249bac4b977adee0ee9771568e8aa3"
-
 [[package]]
 name = "pulldown-cmark"
 version = "0.13.1"
@@ -4863,12 +4756,6 @@ dependencies = [
  "windows-sys 0.60.2",
 ]
 
-[[package]]
-name = "terrors"
-version = "0.3.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "987fd8c678ca950df2a18b2c6e9da6ca511d449278fab3565efe0d49c0c07a5d"
-
 [[package]]
 name = "test-log"
 version = "0.2.19"
@@ -4981,9 +4868,9 @@ dependencies = [
 
 [[package]]
 name = "tinyvec"
-version = "1.10.0"
+version = "1.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bfa5fdc3bce6191a1dbc8c02d5c8bffcf557bafa17c124c5264a458f1b0613fa"
+checksum = "3e61e67053d25a4e82c844e8424039d9745781b3fc4f32b8d55ed50f5f667ef3"
 dependencies = [
  "tinyvec_macros",
 ]

server/Cargo.toml

@@ -20,7 +20,7 @@ tokio = { version = "1.49.0", features = ["full"] }
 ed25519-dalek = { version = "3.0.0-pre.6", features = ["rand_core"] }
 chrono = { version = "0.4.43", features = ["serde"] }
 rand = "0.10.0"
-rustls = "0.23.36"
+rustls = { version = "0.23.36", features = ["aws-lc-rs"] }
 smlang = "0.8.0"
 miette = { version = "7.6.0", features = ["fancy", "serde"] }
 thiserror = "2.0.18"

server/crates/arbiter-client/Cargo.toml

@@ -5,18 +5,4 @@ edition = "2024"
 repository = "https://git.markettakers.org/MarketTakers/arbiter"
 license = "Apache-2.0"
 
-[lints]
-workspace = true
-
 [dependencies]
-arbiter-proto.path = "../arbiter-proto"
-alloy.workspace = 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 = "0.103.9", features = ["aws-lc-rs"] }
-async-trait.workspace = true

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

@@ -1,272 +1,14 @@
-use alloy::{
+pub fn add(left: u64, right: u64) -> u64 {
-    consensus::SignableTransaction,
+    left + right
-    network::TxSigner,
-    primitives::{Address, B256, ChainId, Signature},
-    signers::{Error, Result, Signer},
-};
-use arbiter_proto::{
-    format_challenge,
-    proto::{
-        arbiter_service_client::ArbiterServiceClient,
-        client::{
-            AuthChallengeRequest, AuthChallengeSolution, ClientRequest, ClientResponse,
-            client_connect_error, client_request::Payload as ClientRequestPayload,
-            client_response::Payload as ClientResponsePayload,
-        },
-        evm::{
-            EvmSignTransactionRequest, evm_sign_transaction_response::Result as SignResponseResult,
-        },
-    },
-    url::ArbiterUrl,
-};
-use async_trait::async_trait;
-use ed25519_dalek::Signer as _;
-use tokio::sync::{Mutex, mpsc};
-use tokio_stream::wrappers::ReceiverStream;
-use tonic::transport::ClientTlsConfig;
-
-#[derive(Debug, thiserror::Error)]
-pub enum ConnectError {
-    #[error("Could not establish connection")]
-    Connection(#[from] tonic::transport::Error),
-
-    #[error("Invalid server URI")]
-    InvalidUri(#[from] http::uri::InvalidUri),
-
-    #[error("Invalid CA certificate")]
-    InvalidCaCert(#[from] webpki::Error),
-
-    #[error("gRPC error")]
-    Grpc(#[from] tonic::Status),
-
-    #[error("Auth challenge was not returned by server")]
-    MissingAuthChallenge,
-
-    #[error("Client approval denied by User Agent")]
-    ApprovalDenied,
-
-    #[error("No User Agents online to approve client")]
-    NoUserAgentsOnline,
-
-    #[error("Unexpected auth response payload")]
-    UnexpectedAuthResponse,
 }
 
-#[derive(Debug, thiserror::Error)]
+#[cfg(test)]
-enum ClientSignError {
+mod tests {
-    #[error("Transport channel closed")]
+    use super::*;
-    ChannelClosed,
 
-    #[error("Connection closed by server")]
+    #[test]
-    ConnectionClosed,
+    fn it_works() {
-
+        let result = add(2, 2);
-    #[error("Invalid response payload")]
+        assert_eq!(result, 4);
-    InvalidResponse,
-
-    #[error("Remote signing was rejected")]
-    Rejected,
-}
-
-struct ClientTransport {
-    sender: mpsc::Sender<ClientRequest>,
-    receiver: tonic::Streaming<ClientResponse>,
-}
-
-impl ClientTransport {
-    async fn send(&mut self, request: ClientRequest) -> std::result::Result<(), ClientSignError> {
-        self.sender
-            .send(request)
-            .await
-            .map_err(|_| ClientSignError::ChannelClosed)
-    }
-
-    async fn recv(&mut self) -> std::result::Result<ClientResponse, ClientSignError> {
-        match self.receiver.message().await {
-            Ok(Some(resp)) => Ok(resp),
-            Ok(None) => Err(ClientSignError::ConnectionClosed),
-            Err(_) => Err(ClientSignError::ConnectionClosed),
-        }
-    }
-}
-
-pub struct ArbiterSigner {
-    transport: Mutex<ClientTransport>,
-    address: Address,
-    chain_id: Option<ChainId>,
-}
-
-impl ArbiterSigner {
-    pub async fn connect_grpc(
-        url: ArbiterUrl,
-        key: ed25519_dalek::SigningKey,
-        address: Address,
-    ) -> std::result::Result<Self, ConnectError> {
-        let anchor = webpki::anchor_from_trusted_cert(&url.ca_cert)?.to_owned();
-        let tls = ClientTlsConfig::new().trust_anchor(anchor);
-
-        // NOTE: We intentionally keep the same URL construction strategy as the user-agent crate
-        // to avoid behavior drift between the two clients.
-        let channel = tonic::transport::Channel::from_shared(format!("{}:{}", url.host, url.port))?
-            .tls_config(tls)?
-            .connect()
-            .await?;
-
-        let mut client = ArbiterServiceClient::new(channel);
-        let (tx, rx) = mpsc::channel(16);
-        let response_stream = client.client(ReceiverStream::new(rx)).await?.into_inner();
-
-        let mut transport = ClientTransport {
-            sender: tx,
-            receiver: response_stream,
-        };
-
-        authenticate(&mut transport, key).await?;
-
-        Ok(Self {
-            transport: Mutex::new(transport),
-            address,
-            chain_id: None,
-        })
-    }
-
-    async fn sign_transaction_via_arbiter(
-        &self,
-        tx: &mut dyn SignableTransaction<Signature>,
-    ) -> Result<Signature> {
-        if let Some(chain_id) = self.chain_id
-            && !tx.set_chain_id_checked(chain_id)
-        {
-            return Err(Error::TransactionChainIdMismatch {
-                signer: chain_id,
-                tx: tx.chain_id().unwrap(),
-            });
-        }
-
-        let mut rlp_transaction = Vec::new();
-        tx.encode_for_signing(&mut rlp_transaction);
-
-        let request = ClientRequest {
-            payload: Some(ClientRequestPayload::EvmSignTransaction(
-                EvmSignTransactionRequest {
-                    wallet_address: self.address.as_slice().to_vec(),
-                    rlp_transaction,
-                },
-            )),
-        };
-
-        let mut transport = self.transport.lock().await;
-        transport.send(request).await.map_err(Error::other)?;
-        let response = transport.recv().await.map_err(Error::other)?;
-
-        let payload = response
-            .payload
-            .ok_or_else(|| Error::other(ClientSignError::InvalidResponse))?;
-
-        let ClientResponsePayload::EvmSignTransaction(sign_response) = payload else {
-            return Err(Error::other(ClientSignError::InvalidResponse));
-        };
-
-        let Some(result) = sign_response.result else {
-            return Err(Error::other(ClientSignError::InvalidResponse));
-        };
-
-        match result {
-            SignResponseResult::Signature(bytes) => {
-                Signature::try_from(bytes.as_slice()).map_err(Error::other)
-            }
-            SignResponseResult::EvalError(_) | SignResponseResult::Error(_) => {
-                Err(Error::other(ClientSignError::Rejected))
-            }
-        }
-    }
-}
-
-async fn authenticate(
-    transport: &mut ClientTransport,
-    key: ed25519_dalek::SigningKey,
-) -> std::result::Result<(), ConnectError> {
-    transport
-        .send(ClientRequest {
-            payload: Some(ClientRequestPayload::AuthChallengeRequest(
-                AuthChallengeRequest {
-                    pubkey: key.verifying_key().to_bytes().to_vec(),
-                },
-            )),
-        })
-        .await
-        .map_err(|_| ConnectError::UnexpectedAuthResponse)?;
-
-    let response = transport
-        .recv()
-        .await
-        .map_err(|_| ConnectError::MissingAuthChallenge)?;
-
-    let payload = response.payload.ok_or(ConnectError::MissingAuthChallenge)?;
-    match payload {
-        ClientResponsePayload::AuthChallenge(challenge) => {
-            let challenge_payload = format_challenge(challenge.nonce, &challenge.pubkey);
-            let signature = key.sign(&challenge_payload).to_bytes().to_vec();
-
-            transport
-                .send(ClientRequest {
-                    payload: Some(ClientRequestPayload::AuthChallengeSolution(
-                        AuthChallengeSolution { signature },
-                    )),
-                })
-                .await
-                .map_err(|_| ConnectError::UnexpectedAuthResponse)?;
-
-            // Current server flow does not emit `AuthOk` for SDK clients, so we proceed after
-            // sending the solution. If authentication fails, the first business request will return
-            // a `ClientConnectError` or the stream will close.
-            Ok(())
-        }
-        ClientResponsePayload::ClientConnectError(err) => {
-            match client_connect_error::Code::try_from(err.code)
-                .unwrap_or(client_connect_error::Code::Unknown)
-            {
-                client_connect_error::Code::ApprovalDenied => Err(ConnectError::ApprovalDenied),
-                client_connect_error::Code::NoUserAgentsOnline => {
-                    Err(ConnectError::NoUserAgentsOnline)
-                }
-                client_connect_error::Code::Unknown => Err(ConnectError::UnexpectedAuthResponse),
-            }
-        }
-        _ => Err(ConnectError::UnexpectedAuthResponse),
-    }
-}
-
-#[async_trait]
-impl Signer for ArbiterSigner {
-    async fn sign_hash(&self, _hash: &B256) -> Result<Signature> {
-        Err(Error::other(
-            "hash-only signing is not supported for ArbiterSigner; use transaction signing",
-        ))
-    }
-
-    fn address(&self) -> Address {
-        self.address
-    }
-
-    fn chain_id(&self) -> Option<ChainId> {
-        self.chain_id
-    }
-
-    fn set_chain_id(&mut self, chain_id: Option<ChainId>) {
-        self.chain_id = chain_id;
-    }
-}
-
-#[async_trait]
-impl TxSigner<Signature> for ArbiterSigner {
-    fn address(&self) -> Address {
-        self.address
-    }
-
-    async fn sign_transaction(
-        &self,
-        tx: &mut dyn SignableTransaction<Signature>,
-    ) -> Result<Signature> {
-        self.sign_transaction_via_arbiter(tx).await
     }
 }

server/crates/arbiter-proto/Cargo.toml

@@ -24,7 +24,6 @@ async-trait.workspace = true
 
 [build-dependencies]
 tonic-prost-build = "0.14.3"
-protoc-bin-vendored = "3"
 
 [dev-dependencies]
 rstest.workspace = true

server/crates/arbiter-proto/build.rs

@@ -3,12 +3,6 @@ use tonic_prost_build::configure;
 static PROTOBUF_DIR: &str = "../../../protobufs";
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    if std::env::var("PROTOC").is_err() {
-        println!("cargo:warning=PROTOC environment variable not set, using vendored protoc");
-        let protoc = protoc_bin_vendored::protoc_bin_path().unwrap();
-        unsafe { std::env::set_var("PROTOC", protoc) };
-    }
-
     println!("cargo::rerun-if-changed={PROTOBUF_DIR}");
 
     configure()

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

@@ -1,78 +1,39 @@
-//! Transport-facing abstractions for protocol/session code.
+//! Transport-facing abstractions shared by protocol/session code.
 //!
-//! This module separates three concerns:
+//! This module defines a small duplex interface, [`Bi`], that actors and other
-//!
+//! protocol code can depend on without knowing anything about the concrete
-//! - protocol/session logic wants a small duplex interface ([`Bi`])
+//! transport underneath.
-//! - transport adapters push concrete stream items to an underlying IO layer
-//! - transport boundaries translate between protocol-facing and transport-facing
-//!   item types via direction-specific converters
 //!
 //! [`Bi`] is intentionally minimal and transport-agnostic:
-//! - [`Bi::recv`] yields inbound protocol messages
+//! - [`Bi::recv`] yields inbound messages
-//! - [`Bi::send`] accepts outbound protocol/domain items
+//! - [`Bi::send`] accepts outbound messages
+//!
+//! Transport-specific adapters, including protobuf or gRPC bridges, live in the
+//! crates that own those boundaries rather than in `arbiter-proto`.
 //!
 //! # Generic Ordering Rule
 //!
-//! This module uses a single convention consistently: when a type or trait is
+//! This module consistently uses `Inbound` first and `Outbound` second in
-//! parameterized by protocol message directions, the generic parameters are
+//! generic parameter lists.
-//! declared as `Inbound` first, then `Outbound`.
 //!
 //! For [`Bi`], that means `Bi<Inbound, Outbound>`:
 //! - `recv() -> Option<Inbound>`
 //! - `send(Outbound)`
 //!
-//! For adapter types that are parameterized by direction-specific converters,
+//! [`expect_message`] is a small helper for request/response style flows: it
-//! inbound-related converter parameters are declared before outbound-related
+//! reads one inbound message from a transport and extracts a typed value from
-//! converter parameters.
+//! it, failing if the channel closes or the message shape is not what the
+//! caller expected.
 //!
-//! [`RecvConverter`] and [`SendConverter`] are infallible conversion traits used
+//! [`DummyTransport`] is a no-op implementation useful for tests and local
-//! by adapters to map between protocol-facing and transport-facing item types.
+//! actor execution where no real stream exists.
-//! The traits themselves are not result-aware; adapters decide how transport
-//! errors are handled before (or instead of) conversion.
-//!
-//! [`grpc::GrpcAdapter`] combines:
-//! - a tonic inbound stream
-//! - a Tokio sender for outbound transport items
-//! - a [`RecvConverter`] for the receive path
-//! - a [`SendConverter`] for the send path
-//!
-//! [`DummyTransport`] is a no-op implementation useful for tests and local actor
-//! execution where no real network stream exists.
-//!
-//! # Component Interaction
-//!
-//! ```text
-//! inbound (network -> protocol)
-//! ============================
-//!
-//! tonic::Streaming<RecvTransport>
-//!     -> grpc::GrpcAdapter::recv()
-//!          |
-//!          +--> on `Ok(item)`: RecvConverter::convert(RecvTransport) -> Inbound
-//!          +--> on `Err(status)`: log error and close stream (`None`)
-//!     -> Bi::recv()
-//!     -> protocol/session actor
-//!
-//! outbound (protocol -> network)
-//! ==============================
-//!
-//! protocol/session actor
-//!     -> Bi::send(Outbound)
-//!     -> grpc::GrpcAdapter::send()
-//!          |
-//!          +--> SendConverter::convert(Outbound) -> SendTransport
-//!     -> Tokio mpsc::Sender<SendTransport>
-//!     -> tonic response stream
-//! ```
 //!
 //! # Design Notes
 //!
-//! - `send()` returns [`Error`] only for transport delivery failures (for
+//! - [`Bi::send`] returns [`Error`] only for transport delivery failures, such
-//!   example, when the outbound channel is closed).
+//!   as a closed outbound channel.
-//! - [`grpc::GrpcAdapter`] logs tonic receive errors and treats them as stream
+//! - [`Bi::recv`] returns `None` when the underlying transport closes.
-//!   closure (`None`).
+//! - Message translation is intentionally out of scope for this module.
-//! - When protocol-facing and transport-facing types are identical, use
-//!   [`IdentityRecvConverter`] / [`IdentitySendConverter`].
 
 use std::marker::PhantomData;
 
@@ -114,162 +75,6 @@ pub trait Bi<Inbound, Outbound>: Send + Sync + 'static {
     async fn recv(&mut self) -> Option<Inbound>;
 }
 
-/// Converts transport-facing inbound items into protocol-facing inbound items.
-pub trait RecvConverter: Send + Sync + 'static {
-    type Input;
-    type Output;
-
-    fn convert(&self, item: Self::Input) -> Self::Output;
-}
-
-/// Converts protocol/domain outbound items into transport-facing outbound items.
-pub trait SendConverter: Send + Sync + 'static {
-    type Input;
-    type Output;
-
-    fn convert(&self, item: Self::Input) -> Self::Output;
-}
-
-/// A [`RecvConverter`] that forwards values unchanged.
-pub struct IdentityRecvConverter<T> {
-    _marker: PhantomData<T>,
-}
-
-impl<T> IdentityRecvConverter<T> {
-    pub fn new() -> Self {
-        Self {
-            _marker: PhantomData,
-        }
-    }
-}
-
-impl<T> Default for IdentityRecvConverter<T> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl<T> RecvConverter for IdentityRecvConverter<T>
-where
-    T: Send + Sync + 'static,
-{
-    type Input = T;
-    type Output = T;
-
-    fn convert(&self, item: Self::Input) -> Self::Output {
-        item
-    }
-}
-
-/// A [`SendConverter`] that forwards values unchanged.
-pub struct IdentitySendConverter<T> {
-    _marker: PhantomData<T>,
-}
-
-impl<T> IdentitySendConverter<T> {
-    pub fn new() -> Self {
-        Self {
-            _marker: PhantomData,
-        }
-    }
-}
-
-impl<T> Default for IdentitySendConverter<T> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl<T> SendConverter for IdentitySendConverter<T>
-where
-    T: Send + Sync + 'static,
-{
-    type Input = T;
-    type Output = T;
-
-    fn convert(&self, item: Self::Input) -> Self::Output {
-        item
-    }
-}
-
-/// gRPC-specific transport adapters and helpers.
-pub mod grpc {
-    use async_trait::async_trait;
-    use futures::StreamExt;
-    use tokio::sync::mpsc;
-    use tonic::Streaming;
-
-    use super::{Bi, Error, RecvConverter, SendConverter};
-
-    /// [`Bi`] adapter backed by a tonic gRPC bidirectional stream.
-    ///
-    /// Tonic receive errors are logged and treated as stream closure (`None`).
-    /// The receive converter is only invoked for successful inbound transport
-    /// items.
-    pub struct GrpcAdapter<InboundConverter, OutboundConverter>
-    where
-        InboundConverter: RecvConverter,
-        OutboundConverter: SendConverter,
-    {
-        sender: mpsc::Sender<OutboundConverter::Output>,
-        receiver: Streaming<InboundConverter::Input>,
-        inbound_converter: InboundConverter,
-        outbound_converter: OutboundConverter,
-    }
-
-    impl<InboundTransport, Inbound, InboundConverter, OutboundConverter>
-        GrpcAdapter<InboundConverter, OutboundConverter>
-    where
-        InboundConverter: RecvConverter<Input = InboundTransport, Output = Inbound>,
-        OutboundConverter: SendConverter,
-    {
-        pub fn new(
-            sender: mpsc::Sender<OutboundConverter::Output>,
-            receiver: Streaming<InboundTransport>,
-            inbound_converter: InboundConverter,
-            outbound_converter: OutboundConverter,
-        ) -> Self {
-            Self {
-                sender,
-                receiver,
-                inbound_converter,
-                outbound_converter,
-            }
-        }
-    }
-
-    #[async_trait]
-    impl<InboundConverter, OutboundConverter> Bi<InboundConverter::Output, OutboundConverter::Input>
-        for GrpcAdapter<InboundConverter, OutboundConverter>
-    where
-        InboundConverter: RecvConverter,
-        OutboundConverter: SendConverter,
-        OutboundConverter::Input: Send + 'static,
-        OutboundConverter::Output: Send + 'static,
-    {
-        #[tracing::instrument(level = "trace", skip(self, item))]
-        async fn send(&mut self, item: OutboundConverter::Input) -> Result<(), Error> {
-            let outbound = self.outbound_converter.convert(item);
-            self.sender
-                .send(outbound)
-                .await
-                .map_err(|_| Error::ChannelClosed)
-        }
-
-        #[tracing::instrument(level = "trace", skip(self))]
-        async fn recv(&mut self) -> Option<InboundConverter::Output> {
-            match self.receiver.next().await {
-                Some(Ok(item)) => Some(self.inbound_converter.convert(item)),
-                Some(Err(error)) => {
-                    tracing::error!(error = ?error, "grpc transport recv failed; closing stream");
-                    None
-                }
-                None => None,
-            }
-        }
-    }
-}
-
 /// No-op [`Bi`] transport for tests and manual actor usage.
 ///
 /// `send` drops all items and succeeds. [`Bi::recv`] never resolves and therefore

server/crates/arbiter-server/Cargo.toml

@@ -50,6 +50,7 @@ rsa.workspace = true
 sha2.workspace = true
 spki.workspace = true
 alloy.workspace = true
+prost-types.workspace = true
 arbiter-tokens-registry.path = "../arbiter-tokens-registry"
 
 [dev-dependencies]

server/crates/arbiter-server/migrations/2026-03-15-103112-0000_add_program_client_pubkey_unique/down.sql

@@ -1 +0,0 @@
-DROP INDEX IF EXISTS program_client_public_key_unique;

server/crates/arbiter-server/migrations/2026-03-15-103112-0000_add_program_client_pubkey_unique/up.sql

@@ -1,2 +0,0 @@
-CREATE UNIQUE INDEX program_client_public_key_unique
-    ON program_client (public_key);

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

@@ -3,12 +3,7 @@ use diesel::QueryDsl;
 use diesel_async::RunQueryDsl;
 use kameo::{Actor, messages};
 use miette::Diagnostic;
-use rand::{
+use rand::{RngExt, distr::Alphanumeric, make_rng, rngs::StdRng};
-    RngExt,
-    distr::{Alphanumeric},
-    make_rng,
-    rngs::StdRng,
-};
 use thiserror::Error;
 
 use crate::db::{self, DatabasePool, schema};
@@ -61,7 +56,6 @@ impl Bootstrapper {
 
         drop(conn);
 
-
         let token = if row_count == 0 {
             let token = generate_token().await?;
             Some(token)

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

@@ -1,20 +1,17 @@
-use arbiter_proto::{
+use arbiter_proto::{format_challenge, transport::expect_message};
-    format_challenge,
+use diesel::{
-    proto::client::{
+    ExpressionMethods as _, OptionalExtension as _, QueryDsl as _, dsl::insert_into, update,
-        AuthChallenge, AuthChallengeSolution, ClientConnectError, ClientRequest, ClientResponse,
-        client_connect_error::Code as ConnectErrorCode,
-        client_request::Payload as ClientRequestPayload,
-        client_response::Payload as ClientResponsePayload,
-    },
-    transport::expect_message,
 };
-use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl as _, update};
 use diesel_async::RunQueryDsl as _;
 use ed25519_dalek::VerifyingKey;
+use kameo::error::SendError;
 use tracing::error;
 
 use crate::{
-    actors::client::ClientConnection,
+    actors::{
+        client::{ClientConnection, ConnectErrorCode, Request, Response},
+        router::{self, RequestClientApproval},
+    },
     db::{self, schema::program_client},
 };
 
@@ -34,20 +31,27 @@ pub enum Error {
     DatabaseOperationFailed,
     #[error("Invalid challenge solution")]
     InvalidChallengeSolution,
-    #[error("Client not registered")]
+    #[error("Client approval request failed")]
-    NotRegistered,
+    ApproveError(#[from] ApproveError),
     #[error("Internal error")]
     InternalError,
     #[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(router::ApprovalError),
+}
+
 /// Atomically reads and increments the nonce for a known client.
 /// Returns `None` if the pubkey is not registered.
-async fn get_nonce(
+async fn get_nonce(db: &db::DatabasePool, pubkey: &VerifyingKey) -> Result<Option<i32>, Error> {
-    db: &db::DatabasePool,
-    pubkey: &VerifyingKey,
-) -> Result<Option<(i32, i32)>, Error> {
     let pubkey_bytes = pubkey.as_bytes().to_vec();
 
     let mut conn = db.get().await.map_err(|e| {
@@ -58,10 +62,10 @@ async fn get_nonce(
     conn.exclusive_transaction(|conn| {
         let pubkey_bytes = pubkey_bytes.clone();
         Box::pin(async move {
-            let Some((client_id, current_nonce)) = program_client::table
+            let Some(current_nonce) = program_client::table
                 .filter(program_client::public_key.eq(&pubkey_bytes))
-                .select((program_client::id, program_client::nonce))
+                .select(program_client::nonce)
-                .first::<(i32, i32)>(conn)
+                .first::<i32>(conn)
                 .await
                 .optional()?
             else {
@@ -74,7 +78,7 @@ async fn get_nonce(
                 .execute(conn)
                 .await?;
 
-            Ok(Some((client_id, current_nonce)))
+            Ok(Some(current_nonce))
         })
     })
     .await
@@ -84,20 +88,71 @@ async fn get_nonce(
     })
 }
 
+async fn approve_new_client(
+    actors: &crate::actors::GlobalActors,
+    pubkey: VerifyingKey,
+) -> Result<(), Error> {
+    let result = actors
+        .router
+        .ask(RequestClientApproval {
+            client_pubkey: pubkey,
+        })
+        .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 router failed");
+            Err(Error::ApproveError(ApproveError::Internal))
+        }
+    }
+}
+
+async fn insert_client(db: &db::DatabasePool, pubkey: &VerifyingKey) -> Result<(), Error> {
+    let now = std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs() as i32;
+
+    let mut conn = db.get().await.map_err(|e| {
+        error!(error = ?e, "Database pool error");
+        Error::DatabasePoolUnavailable
+    })?;
+
+    insert_into(program_client::table)
+        .values((
+            program_client::public_key.eq(pubkey.as_bytes().to_vec()),
+            program_client::nonce.eq(1), // pre-incremented; challenge uses 0
+            program_client::created_at.eq(now),
+            program_client::updated_at.eq(now),
+        ))
+        .execute(&mut conn)
+        .await
+        .map_err(|e| {
+            error!(error = ?e, "Failed to insert new client");
+            Error::DatabaseOperationFailed
+        })?;
+
+    Ok(())
+}
+
 async fn challenge_client(
     props: &mut ClientConnection,
     pubkey: VerifyingKey,
     nonce: i32,
 ) -> Result<(), Error> {
-    let challenge = AuthChallenge {
+    let challenge_pubkey = pubkey.as_bytes().to_vec();
-        pubkey: pubkey.as_bytes().to_vec(),
-        nonce,
-    };
 
     props
         .transport
-        .send(Ok(ClientResponse {
+        .send(Ok(Response::AuthChallenge {
-            payload: Some(ClientResponsePayload::AuthChallenge(challenge.clone())),
+            pubkey: challenge_pubkey.clone(),
+            nonce,
         }))
         .await
         .map_err(|e| {
@@ -105,20 +160,17 @@ async fn challenge_client(
             Error::Transport
         })?;
 
-    let AuthChallengeSolution { signature } =
+    let signature = expect_message(&mut *props.transport, |req: Request| match req {
-        expect_message(&mut *props.transport, |req: ClientRequest| {
+        Request::AuthChallengeSolution { signature } => Some(signature),
-            match req.payload? {
+        _ => None,
-                ClientRequestPayload::AuthChallengeSolution(s) => Some(s),
+    })
-                _ => None,
+    .await
-            }
+    .map_err(|e| {
-        })
+        error!(error = ?e, "Failed to receive challenge solution");
-        .await
+        Error::Transport
-        .map_err(|e| {
+    })?;
-            error!(error = ?e, "Failed to receive challenge solution");
-            Error::Transport
-        })?;
 
-    let formatted = format_challenge(nonce, &challenge.pubkey);
+    let formatted = format_challenge(nonce, &challenge_pubkey);
     let sig = signature.as_slice().try_into().map_err(|_| {
         error!("Invalid signature length");
         Error::InvalidChallengeSolution
@@ -134,48 +186,50 @@ async fn challenge_client(
 
 fn connect_error_code(err: &Error) -> ConnectErrorCode {
     match err {
-        Error::NotRegistered => ConnectErrorCode::ApprovalDenied,
+        Error::ApproveError(ApproveError::Denied) => ConnectErrorCode::ApprovalDenied,
+        Error::ApproveError(ApproveError::Upstream(
+            router::ApprovalError::NoUserAgentsConnected,
+        )) => ConnectErrorCode::NoUserAgentsOnline,
         _ => ConnectErrorCode::Unknown,
     }
 }
 
-async fn authenticate(props: &mut ClientConnection) -> Result<(VerifyingKey, i32), Error> {
+async fn authenticate(props: &mut ClientConnection) -> Result<VerifyingKey, Error> {
-    let Some(ClientRequest {
+    let Some(Request::AuthChallengeRequest {
-        payload: Some(ClientRequestPayload::AuthChallengeRequest(challenge)),
+        pubkey: challenge_pubkey,
     }) = props.transport.recv().await
     else {
         return Err(Error::Transport);
     };
 
-    let pubkey_bytes = challenge
+    let pubkey_bytes = challenge_pubkey
-        .pubkey
         .as_array()
         .ok_or(Error::InvalidClientPubkeyLength)?;
     let pubkey =
         VerifyingKey::from_bytes(pubkey_bytes).map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
 
-    let (client_id, nonce) = match get_nonce(&props.db, &pubkey).await? {
+    let nonce = match get_nonce(&props.db, &pubkey).await? {
-        Some((client_id, nonce)) => (client_id, nonce),
+        Some(nonce) => nonce,
-        None => return Err(Error::NotRegistered),
+        None => {
+            approve_new_client(&props.actors, pubkey).await?;
+            insert_client(&props.db, &pubkey).await?;
+            0
+        }
     };
 
     challenge_client(props, pubkey, nonce).await?;
 
-    Ok((pubkey, client_id))
+    Ok(pubkey)
 }
 
 pub async fn authenticate_and_create(mut props: ClientConnection) -> Result<ClientSession, Error> {
     match authenticate(&mut props).await {
-        Ok((_pubkey, client_id)) => Ok(ClientSession::new(props, client_id)),
+        Ok(_pubkey) => Ok(ClientSession::new(props)),
         Err(err) => {
             let code = connect_error_code(&err);
             let _ = props
                 .transport
-                .send(Ok(ClientResponse {
+                .send(Ok(Response::ClientConnectError { code }))
-                    payload: Some(ClientResponsePayload::ClientConnectError(
-                        ClientConnectError { code: code.into() },
-                    )),
-                }))
                 .await;
             Err(err)
         }

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

@@ -1,7 +1,4 @@
-use arbiter_proto::{
+use arbiter_proto::transport::Bi;
-    proto::client::{ClientRequest, ClientResponse},
-    transport::Bi,
-};
 use kameo::actor::Spawn;
 use tracing::{error, info};
 
@@ -24,7 +21,27 @@ pub enum ClientError {
     Auth(#[from] auth::Error),
 }
 
-pub type Transport = Box<dyn Bi<ClientRequest, Result<ClientResponse, ClientError>> + Send>;
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ConnectErrorCode {
+    Unknown,
+    ApprovalDenied,
+    NoUserAgentsOnline,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum Request {
+    AuthChallengeRequest { pubkey: Vec<u8> },
+    AuthChallengeSolution { signature: Vec<u8> },
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum Response {
+    AuthChallenge { pubkey: Vec<u8>, nonce: i32 },
+    AuthOk,
+    ClientConnectError { code: ConnectErrorCode },
+}
+
+pub type Transport = Box<dyn Bi<Request, Result<Response, ClientError>> + Send>;
 
 pub struct ClientConnection {
     pub(crate) db: db::DatabasePool,

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

@@ -1,13 +1,3 @@
-use alloy::{consensus::TxEip1559, primitives::Address, rlp::Decodable};
-use arbiter_proto::proto::{
-    client::{
-        ClientRequest, ClientResponse, client_request::Payload as ClientRequestPayload,
-        client_response::Payload as ClientResponsePayload,
-    },
-    evm::{
-        EvmError, EvmSignTransactionResponse, evm_sign_transaction_response::Result as SignResult,
-    },
-};
 use kameo::Actor;
 use tokio::select;
 use tracing::{error, info};
@@ -15,8 +5,7 @@ use tracing::{error, info};
 use crate::{
     actors::{
         GlobalActors,
-        client::{ClientConnection, ClientError},
+        client::{ClientConnection, ClientError, Request, Response},
-        evm::ClientSignTransaction,
         router::RegisterClient,
     },
     db,
@@ -24,64 +13,20 @@ use crate::{
 
 pub struct ClientSession {
     props: ClientConnection,
-    client_id: i32,
 }
 
 impl ClientSession {
-    pub(crate) fn new(props: ClientConnection, client_id: i32) -> Self {
+    pub(crate) fn new(props: ClientConnection) -> Self {
-        Self { props, client_id }
+        Self { props }
     }
 
-    pub async fn process_transport_inbound(&mut self, req: ClientRequest) -> Output {
+    pub async fn process_transport_inbound(&mut self, req: Request) -> Output {
-        let msg = req.payload.ok_or_else(|| {
+        let _ = req;
-            error!(actor = "client", "Received message with no payload");
+        Err(ClientError::UnexpectedRequestPayload)
-            ClientError::MissingRequestPayload
-        })?;
-
-        match msg {
-            ClientRequestPayload::EvmSignTransaction(sign_req) => {
-                let wallet_address: [u8; 20] = sign_req
-                    .wallet_address
-                    .try_into()
-                    .map_err(|_| ClientError::UnexpectedRequestPayload)?;
-
-                let mut rlp_bytes: &[u8] = &sign_req.rlp_transaction;
-                let tx = TxEip1559::decode(&mut rlp_bytes)
-                    .map_err(|_| ClientError::UnexpectedRequestPayload)?;
-
-                let result = self
-                    .props
-                    .actors
-                    .evm
-                    .ask(ClientSignTransaction {
-                        client_id: self.client_id,
-                        wallet_address: Address::from_slice(&wallet_address),
-                        transaction: tx,
-                    })
-                    .await;
-
-                let response_result = match result {
-                    Ok(signature) => SignResult::Signature(signature.as_bytes().to_vec()),
-                    Err(err) => {
-                        error!(?err, "client sign transaction failed");
-                        SignResult::Error(EvmError::Internal.into())
-                    }
-                };
-
-                Ok(ClientResponse {
-                    payload: Some(ClientResponsePayload::EvmSignTransaction(
-                        EvmSignTransactionResponse {
-                            result: Some(response_result),
-                        },
-                    )),
-                })
-            }
-            _ => Err(ClientError::UnexpectedRequestPayload),
-        }
     }
 }
 
-type Output = Result<ClientResponse, ClientError>;
+type Output = Result<Response, ClientError>;
 
 impl Actor for ClientSession {
     type Args = Self;
@@ -143,9 +88,6 @@ impl ClientSession {
         use arbiter_proto::transport::DummyTransport;
         let transport: super::Transport = Box::new(DummyTransport::new());
         let props = ClientConnection::new(db, transport, actors);
-        Self {
+        Self { props }
-            props,
-            client_id: 0,
-        }
     }
 }

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

@@ -1,21 +1,26 @@
 use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
-use diesel::{ExpressionMethods, OptionalExtension as _, QueryDsl, SelectableHelper as _, dsl::insert_into};
+use diesel::{
+    ExpressionMethods, OptionalExtension as _, QueryDsl, SelectableHelper as _, dsl::insert_into,
+};
 use diesel_async::RunQueryDsl;
 use kameo::{Actor, actor::ActorRef, messages};
-use memsafe::MemSafe;
 use rand::{SeedableRng, rng, rngs::StdRng};
 
 use crate::{
     actors::keyholder::{CreateNew, Decrypt, KeyHolder},
-    db::{self, DatabasePool, models::{self, EvmBasicGrant, SqliteTimestamp}, schema},
+    db::{
+        self, DatabasePool,
+        models::{self, SqliteTimestamp},
+        schema,
+    },
     evm::{
-        self, RunKind,
+        self, ListGrantsError, RunKind,
         policies::{
-            FullGrant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
+            FullGrant, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
-            ether_transfer::EtherTransfer,
+            ether_transfer::EtherTransfer, token_transfers::TokenTransfer,
-            token_transfers::TokenTransfer,
         },
     },
+    safe_cell::{SafeCell, SafeCellHandle as _},
 };
 
 pub use crate::evm::safe_signer;
@@ -88,7 +93,12 @@ impl EvmActor {
         // todo: audit
         let rng = StdRng::from_rng(&mut rng());
         let engine = evm::Engine::new(db.clone());
-        Self { keyholder, db, rng, engine }
+        Self {
+            keyholder,
+            db,
+            rng,
+            engine,
+        }
     }
 }
 
@@ -98,11 +108,7 @@ impl EvmActor {
     pub async fn generate(&mut self) -> Result<Address, Error> {
         let (mut key_cell, address) = safe_signer::generate(&mut self.rng);
 
-        // Move raw key bytes into a Vec<u8> MemSafe for KeyHolder
+        let plaintext = key_cell.read_inline(|reader| SafeCell::new(reader.to_vec()));
-        let plaintext = {
-            let reader = key_cell.read().expect("MemSafe read");
-            MemSafe::new(reader.to_vec()).expect("MemSafe allocation")
-        };
 
         let aead_id: i32 = self
             .keyholder
@@ -149,12 +155,24 @@ impl EvmActor {
         match grant {
             SpecificGrant::EtherTransfer(settings) => {
                 self.engine
-                    .create_grant::<EtherTransfer>(client_id, FullGrant { basic, specific: settings })
+                    .create_grant::<EtherTransfer>(
+                        client_id,
+                        FullGrant {
+                            basic,
+                            specific: settings,
+                        },
+                    )
                     .await
             }
             SpecificGrant::TokenTransfer(settings) => {
                 self.engine
-                    .create_grant::<TokenTransfer>(client_id, FullGrant { basic, specific: settings })
+                    .create_grant::<TokenTransfer>(
+                        client_id,
+                        FullGrant {
+                            basic,
+                            specific: settings,
+                        },
+                    )
                     .await
             }
         }
@@ -172,19 +190,12 @@ impl EvmActor {
     }
 
     #[message]
-    pub async fn useragent_list_grants(
+    pub async fn useragent_list_grants(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
-        &mut self,
+        match self.engine.list_all_grants().await {
-        wallet_id: Option<i32>,
+            Ok(grants) => Ok(grants),
-    ) -> Result<Vec<EvmBasicGrant>, Error> {
+            Err(ListGrantsError::Database(db)) => Err(Error::Database(db)),
-        let mut conn = self.db.get().await?;
+            Err(ListGrantsError::Pool(pool)) => Err(Error::DatabasePool(pool)),
-        let mut query = schema::evm_basic_grant::table
-            .select(EvmBasicGrant::as_select())
-            .filter(schema::evm_basic_grant::revoked_at.is_null())
-            .into_boxed();
-        if let Some(wid) = wallet_id {
-            query = query.filter(schema::evm_basic_grant::wallet_id.eq(wid));
         }
-        Ok(query.load(&mut conn).await?)
     }
 
     #[message]
@@ -204,8 +215,14 @@ impl EvmActor {
             .ok_or(SignTransactionError::WalletNotFound)?;
         drop(conn);
 
-        let meaning = self.engine
+        let meaning = self
-            .evaluate_transaction(wallet.id, client_id, transaction.clone(), RunKind::Execution)
+            .engine
+            .evaluate_transaction(
+                wallet.id,
+                client_id,
+                transaction.clone(),
+                RunKind::Execution,
+            )
             .await?;
 
         Ok(meaning)
@@ -228,16 +245,23 @@ impl EvmActor {
             .ok_or(SignTransactionError::WalletNotFound)?;
         drop(conn);
 
-        let raw_key: MemSafe<Vec<u8>> = self
+        let raw_key: SafeCell<Vec<u8>> = self
             .keyholder
-            .ask(Decrypt { aead_id: wallet.aead_encrypted_id })
+            .ask(Decrypt {
+                aead_id: wallet.aead_encrypted_id,
+            })
             .await
             .map_err(|_| SignTransactionError::KeyholderSend)?;
 
-        let signer = safe_signer::SafeSigner::from_memsafe(raw_key)?;
+        let signer = safe_signer::SafeSigner::from_cell(raw_key)?;
 
         self.engine
-            .evaluate_transaction(wallet.id, client_id, transaction.clone(), RunKind::Execution)
+            .evaluate_transaction(
+                wallet.id,
+                client_id,
+                transaction.clone(),
+                RunKind::Execution,
+            )
             .await?;
 
         use alloy::network::TxSignerSync as _;

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

@@ -5,12 +5,13 @@ use chacha20poly1305::{
     AeadInPlace, Key, KeyInit as _, XChaCha20Poly1305, XNonce,
     aead::{AeadMut, Error, Payload},
 };
-use memsafe::MemSafe;
 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();
 
@@ -47,40 +48,33 @@ impl<'a> TryFrom<&'a [u8]> for Nonce {
     }
 }
 
-pub struct KeyCell(pub MemSafe<Key>);
+pub struct KeyCell(pub SafeCell<Key>);
-impl From<MemSafe<Key>> for KeyCell {
+impl From<SafeCell<Key>> for KeyCell {
-    fn from(value: MemSafe<Key>) -> Self {
+    fn from(value: SafeCell<Key>) -> Self {
         Self(value)
     }
 }
-impl TryFrom<MemSafe<Vec<u8>>> for KeyCell {
+impl TryFrom<SafeCell<Vec<u8>>> for KeyCell {
     type Error = ();
 
-    fn try_from(mut value: MemSafe<Vec<u8>>) -> Result<Self, Self::Error> {
+    fn try_from(mut value: SafeCell<Vec<u8>>) -> Result<Self, Self::Error> {
-        let value = value.read().unwrap();
+        let value = value.read();
         if value.len() != size_of::<Key>() {
             return Err(());
         }
-        let mut cell = MemSafe::new(Key::default()).unwrap();
+        let cell = SafeCell::new_inline(|cell_write: &mut Key| {
-        {
+            cell_write.copy_from_slice(&value);
-            let mut cell_write = cell.write().unwrap();
+        });
-            let cell_slice: &mut [u8] = cell_write.as_mut();
-            cell_slice.copy_from_slice(&value);
-        }
         Ok(Self(cell))
     }
 }
 
 impl KeyCell {
     pub fn new_secure_random() -> Self {
-        let mut key = MemSafe::new(Key::default()).unwrap();
+        let key = SafeCell::new_inline(|key_buffer: &mut Key| {
-        {
-            let mut key_buffer = key.write().unwrap();
-            let key_buffer: &mut [u8] = key_buffer.as_mut();
-
             let mut rng = StdRng::try_from_rng(&mut SysRng).unwrap();
             rng.fill_bytes(key_buffer);
-        }
+        });
 
         key.into()
     }
@@ -91,7 +85,7 @@ impl KeyCell {
         associated_data: &[u8],
         mut buffer: impl AsMut<Vec<u8>>,
     ) -> Result<(), Error> {
-        let key_reader = self.0.read().unwrap();
+        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());
@@ -102,13 +96,13 @@ impl KeyCell {
         &mut self,
         nonce: &Nonce,
         associated_data: &[u8],
-        buffer: &mut MemSafe<Vec<u8>>,
+        buffer: &mut SafeCell<Vec<u8>>,
     ) -> Result<(), Error> {
-        let key_reader = self.0.read().unwrap();
+        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().unwrap();
+        let mut buffer = buffer.write();
         let buffer: &mut Vec<u8> = buffer.as_mut();
         cipher.decrypt_in_place(nonce, associated_data, buffer)
     }
@@ -119,7 +113,7 @@ impl KeyCell {
         associated_data: &[u8],
         plaintext: impl AsRef<[u8]>,
     ) -> Result<Vec<u8>, Error> {
-        let key_reader = self.0.read().unwrap();
+        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());
@@ -146,19 +140,18 @@ pub fn generate_salt() -> Salt {
 
 /// User password might be of different length, have not enough entropy, etc...
 /// Derive a fixed-length key from the password using Argon2id, which is designed for password hashing and key derivation.
-pub fn derive_seal_key(mut password: MemSafe<Vec<u8>>, salt: &Salt) -> KeyCell {
+pub fn derive_seal_key(mut password: SafeCell<Vec<u8>>, salt: &Salt) -> KeyCell {
     let params = argon2::Params::new(262_144, 3, 4, None).unwrap();
     let hasher = Argon2::new(Algorithm::Argon2id, argon2::Version::V0x13, params);
-    let mut key = MemSafe::new(Key::default()).unwrap();
+    let mut key = SafeCell::new(Key::default());
-    {
+    password.read_inline(|password_source| {
-        let password_source = password.read().unwrap();
+        let mut key_buffer = key.write();
-        let mut key_buffer = key.write().unwrap();
         let key_buffer: &mut [u8] = key_buffer.as_mut();
 
         hasher
             .hash_password_into(password_source.deref(), salt, key_buffer)
             .unwrap();
-    }
+    });
 
     key.into()
 }
@@ -166,20 +159,20 @@ pub fn derive_seal_key(mut password: MemSafe<Vec<u8>>, salt: &Salt) -> KeyCell {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use memsafe::MemSafe;
+    use crate::safe_cell::SafeCell;
 
     #[test]
     pub fn derive_seal_key_deterministic() {
         static PASSWORD: &[u8] = b"password";
-        let password = MemSafe::new(PASSWORD.to_vec()).unwrap();
+        let password = SafeCell::new(PASSWORD.to_vec());
-        let password2 = MemSafe::new(PASSWORD.to_vec()).unwrap();
+        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().unwrap();
+        let key1_reader = key1.0.read();
-        let key2_reader = key2.0.read().unwrap();
+        let key2_reader = key2.0.read();
 
         assert_eq!(key1_reader.deref(), key2_reader.deref());
     }
@@ -187,11 +180,11 @@ mod tests {
     #[test]
     pub fn successful_derive() {
         static PASSWORD: &[u8] = b"password";
-        let password = MemSafe::new(PASSWORD.to_vec()).unwrap();
+        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().unwrap();
+        let key_reader = key.0.read();
         let key_ref = key_reader.deref();
 
         assert_ne!(key_ref.as_slice(), &[0u8; 32][..]);
@@ -200,7 +193,7 @@ mod tests {
     #[test]
     pub fn encrypt_decrypt() {
         static PASSWORD: &[u8] = b"password";
-        let password = MemSafe::new(PASSWORD.to_vec()).unwrap();
+        let password = SafeCell::new(PASSWORD.to_vec());
         let salt = generate_salt();
 
         let mut key = derive_seal_key(password, &salt);
@@ -212,12 +205,12 @@ mod tests {
             .unwrap();
         assert_ne!(buffer, b"secret data");
 
-        let mut buffer = MemSafe::new(buffer).unwrap();
+        let mut buffer = SafeCell::new(buffer);
 
         key.decrypt_in_place(&nonce, associated_data, &mut buffer)
             .unwrap();
 
-        let buffer = buffer.read().unwrap();
+        let buffer = buffer.read();
         assert_eq!(*buffer, b"secret data");
     }
 

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

@@ -5,14 +5,17 @@ use diesel::{
 };
 use diesel_async::{AsyncConnection, RunQueryDsl};
 use kameo::{Actor, Reply, messages};
-use memsafe::MemSafe;
 use strum::{EnumDiscriminants, IntoDiscriminant};
 use tracing::{error, info};
 
-use crate::db::{
+use crate::safe_cell::SafeCell;
-    self,
+use crate::{
-    models::{self, RootKeyHistory},
+    db::{
-    schema::{self},
+        self,
+        models::{self, RootKeyHistory},
+        schema::{self},
+    },
+    safe_cell::SafeCellHandle as _,
 };
 use encryption::v1::{self, KeyCell, Nonce};
 
@@ -136,7 +139,7 @@ impl KeyHolder {
     }
 
     #[message]
-    pub async fn bootstrap(&mut self, seal_key_raw: MemSafe<Vec<u8>>) -> Result<(), Error> {
+    pub async fn bootstrap(&mut self, seal_key_raw: SafeCell<Vec<u8>>) -> Result<(), Error> {
         if !matches!(self.state, State::Unbootstrapped) {
             return Err(Error::AlreadyBootstrapped);
         }
@@ -148,16 +151,15 @@ impl KeyHolder {
         let root_key_nonce = v1::Nonce::default();
         let data_encryption_nonce = v1::Nonce::default();
 
-        let root_key_ciphertext: Vec<u8> = {
+        let root_key_ciphertext: Vec<u8> = root_key.0.read_inline(|reader| {
-            let root_key_reader = root_key.0.read().unwrap();
+            let root_key_reader = reader.as_slice();
-            let root_key_reader = root_key_reader.as_slice();
             seal_key
                 .encrypt(&root_key_nonce, v1::ROOT_KEY_TAG, root_key_reader)
                 .map_err(|err| {
                     error!(?err, "Fatal bootstrap error");
                     Error::Encryption(err)
-                })?
+                })
-        };
+        })?;
 
         let mut conn = self.db.get().await?;
 
@@ -199,7 +201,7 @@ impl KeyHolder {
     }
 
     #[message]
-    pub async fn try_unseal(&mut self, seal_key_raw: MemSafe<Vec<u8>>) -> Result<(), Error> {
+    pub async fn try_unseal(&mut self, seal_key_raw: SafeCell<Vec<u8>>) -> Result<(), Error> {
         let State::Sealed {
             root_key_history_id,
         } = &self.state
@@ -225,7 +227,7 @@ impl KeyHolder {
         })?;
         let mut seal_key = v1::derive_seal_key(seal_key_raw, &salt);
 
-        let mut root_key = MemSafe::new(current_key.ciphertext.clone()).unwrap();
+        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(
             |_| {
@@ -256,7 +258,7 @@ impl KeyHolder {
 
     // Decrypts the `aead_encrypted` entry with the given ID and returns the plaintext
     #[message]
-    pub async fn decrypt(&mut self, aead_id: i32) -> Result<MemSafe<Vec<u8>>, Error> {
+    pub async fn decrypt(&mut self, aead_id: i32) -> Result<SafeCell<Vec<u8>>, Error> {
         let State::Unsealed { root_key, .. } = &mut self.state else {
             return Err(Error::NotBootstrapped);
         };
@@ -279,14 +281,14 @@ impl KeyHolder {
             );
             Error::BrokenDatabase
         })?;
-        let mut output = MemSafe::new(row.ciphertext).unwrap();
+        let mut output = SafeCell::new(row.ciphertext);
         root_key.decrypt_in_place(&nonce, v1::TAG, &mut output)?;
         Ok(output)
     }
 
     // Creates new `aead_encrypted` entry in the database and returns it's ID
     #[message]
-    pub async fn create_new(&mut self, mut plaintext: MemSafe<Vec<u8>>) -> Result<i32, Error> {
+    pub async fn create_new(&mut self, mut plaintext: SafeCell<Vec<u8>>) -> Result<i32, Error> {
         let State::Unsealed {
             root_key,
             root_key_history_id,
@@ -299,7 +301,7 @@ impl KeyHolder {
         // Borrow checker note: &mut borrow a few lines above is disjoint from this field
         let nonce = Self::get_new_nonce(&self.db, *root_key_history_id).await?;
 
-        let mut ciphertext_buffer = plaintext.write().unwrap();
+        let mut ciphertext_buffer = plaintext.write();
         let ciphertext_buffer: &mut Vec<u8> = ciphertext_buffer.as_mut();
         root_key.encrypt_in_place(&nonce, v1::TAG, &mut *ciphertext_buffer)?;
 
@@ -313,7 +315,7 @@ impl KeyHolder {
                 current_nonce: nonce.to_vec(),
                 schema_version: 1,
                 associated_root_key_id: *root_key_history_id,
-                created_at: Utc::now().into()
+                created_at: Utc::now().into(),
             })
             .returning(schema::aead_encrypted::id)
             .get_result(&mut conn)
@@ -348,15 +350,17 @@ mod tests {
     use diesel::SelectableHelper;
 
     use diesel_async::RunQueryDsl;
-    use memsafe::MemSafe;
 
-    use crate::db::{self};
+    use crate::{
+        db::{self},
+        safe_cell::SafeCell,
+    };
 
     use super::*;
 
     async fn bootstrapped_actor(db: &db::DatabasePool) -> KeyHolder {
         let mut actor = KeyHolder::new(db.clone()).await.unwrap();
-        let seal_key = MemSafe::new(b"test-seal-key".to_vec()).unwrap();
+        let seal_key = SafeCell::new(b"test-seal-key".to_vec());
         actor.bootstrap(seal_key).await.unwrap();
         actor
     }
@@ -391,7 +395,7 @@ mod tests {
         assert_eq!(root_row.data_encryption_nonce, n2.to_vec());
 
         let id = actor
-            .create_new(MemSafe::new(b"post-interleave".to_vec()).unwrap())
+            .create_new(SafeCell::new(b"post-interleave".to_vec()))
             .await
             .unwrap();
         let row: models::AeadEncrypted = schema::aead_encrypted::table

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

@@ -1,14 +1,20 @@
 use std::{collections::HashMap, ops::ControlFlow};
 
+use ed25519_dalek::VerifyingKey;
 use kameo::{
     Actor,
     actor::{ActorId, ActorRef},
     messages,
     prelude::{ActorStopReason, Context, WeakActorRef},
+    reply::DelegatedReply,
 };
-use tracing::info;
+use tokio::{sync::watch, task::JoinSet};
+use tracing::{info, warn};
 
-use crate::actors::{client::session::ClientSession, user_agent::session::UserAgentSession};
+use crate::actors::{
+    client::session::ClientSession,
+    user_agent::session::{RequestNewClientApproval, UserAgentSession},
+};
 
 #[derive(Default)]
 pub struct MessageRouter {
@@ -50,6 +56,73 @@ impl Actor for MessageRouter {
     }
 }
 
+#[derive(Debug, thiserror::Error, Clone, PartialEq, Eq, Hash)]
+pub enum ApprovalError {
+    #[error("No user agents connected")]
+    NoUserAgentsConnected,
+}
+
+async fn request_client_approval(
+    user_agents: &[WeakActorRef<UserAgentSession>],
+    client_pubkey: VerifyingKey,
+) -> Result<bool, ApprovalError> {
+    if user_agents.is_empty() {
+        return Err(ApprovalError::NoUserAgentsConnected);
+    }
+
+    let mut pool = JoinSet::new();
+    let (cancel_tx, cancel_rx) = watch::channel(());
+
+    for weak_ref in user_agents {
+        match weak_ref.upgrade() {
+            Some(agent) => {
+                let cancel_rx = cancel_rx.clone();
+                pool.spawn(async move {
+                    agent
+                        .ask(RequestNewClientApproval {
+                            client_pubkey,
+                            cancel_flag: cancel_rx.clone(),
+                        })
+                        .await
+                });
+            }
+            None => {
+                warn!(
+                    id = weak_ref.id().to_string(),
+                    actor = "MessageRouter",
+                    event = "useragent.disconnected_before_approval"
+                );
+            }
+        }
+    }
+
+    while let Some(result) = pool.join_next().await {
+        match result {
+            Ok(Ok(approved)) => {
+                // cancel other pending requests
+                let _ = cancel_tx.send(());
+                return Ok(approved);
+            }
+            Ok(Err(err)) => {
+                warn!(
+                    ?err,
+                    actor = "MessageRouter",
+                    event = "useragent.approval_error"
+                );
+            }
+            Err(err) => {
+                warn!(
+                    ?err,
+                    actor = "MessageRouter",
+                    event = "useragent.approval_task_failed"
+                );
+            }
+        }
+    }
+
+    Err(ApprovalError::NoUserAgentsConnected)
+}
+
 #[messages]
 impl MessageRouter {
     #[message(ctx)]
@@ -73,4 +146,29 @@ impl MessageRouter {
         ctx.actor_ref().link(&actor).await;
         self.clients.insert(actor.id(), actor);
     }
+
+    #[message(ctx)]
+    pub async fn request_client_approval(
+        &mut self,
+        client_pubkey: VerifyingKey,
+        ctx: &mut Context<Self, DelegatedReply<Result<bool, ApprovalError>>>,
+    ) -> DelegatedReply<Result<bool, ApprovalError>> {
+        let (reply, Some(reply_sender)) = ctx.reply_sender() else {
+            panic!("Exptected `request_client_approval` to have callback channel");
+        };
+
+        let weak_refs = self
+            .user_agents
+            .values()
+            .map(|agent| agent.downgrade())
+            .collect::<Vec<_>>();
+
+        // handle in subtask to not to lock the actor
+        tokio::task::spawn(async move {
+            let result = request_client_approval(&weak_refs, client_pubkey).await;
+            reply_sender.send(result);
+        });
+
+        reply
+    }
 }

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

@@ -1,12 +1,9 @@
-use arbiter_proto::proto::user_agent::{
-    AuthChallengeRequest, AuthChallengeSolution, KeyType as ProtoKeyType, UserAgentRequest,
-    user_agent_request::Payload as UserAgentRequestPayload,
-};
 use tracing::error;
 
 use crate::actors::user_agent::{
-    UserAgentConnection,
+    Request, UserAgentConnection,
-    auth::state::{AuthContext, AuthPublicKey, AuthStateMachine},
+    auth::state::{AuthContext, AuthStateMachine},
+    AuthPublicKey,
     session::UserAgentSession,
 };
 
@@ -37,54 +34,20 @@ pub enum Error {
 mod state;
 use state::*;
 
-fn parse_pubkey(key_type: ProtoKeyType, pubkey: Vec<u8>) -> Result<AuthPublicKey, Error> {
+fn parse_auth_event(payload: Request) -> Result<AuthEvents, Error> {
-    match key_type {
-        // UNSPECIFIED treated as Ed25519 for backward compatibility
-        ProtoKeyType::Unspecified | ProtoKeyType::Ed25519 => {
-            let pubkey_bytes = pubkey.as_array().ok_or(Error::InvalidClientPubkeyLength)?;
-            let key = ed25519_dalek::VerifyingKey::from_bytes(pubkey_bytes)
-                .map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
-            Ok(AuthPublicKey::Ed25519(key))
-        }
-        ProtoKeyType::EcdsaSecp256k1 => {
-            // Public key is sent as 33-byte SEC1 compressed point
-            let key = k256::ecdsa::VerifyingKey::from_sec1_bytes(&pubkey)
-                .map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
-            Ok(AuthPublicKey::EcdsaSecp256k1(key))
-        }
-        ProtoKeyType::Rsa => {
-            use rsa::pkcs8::DecodePublicKey as _;
-            let key = rsa::RsaPublicKey::from_public_key_der(&pubkey)
-                .map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
-            Ok(AuthPublicKey::Rsa(key))
-        }
-    }
-}
-
-fn parse_auth_event(payload: UserAgentRequestPayload) -> Result<AuthEvents, Error> {
     match payload {
-        UserAgentRequestPayload::AuthChallengeRequest(AuthChallengeRequest {
+        Request::AuthChallengeRequest {
             pubkey,
             bootstrap_token: None,
-            key_type,
+        } => Ok(AuthEvents::AuthRequest(ChallengeRequest { pubkey })),
-        }) => {
+        Request::AuthChallengeRequest {
-            let kt = ProtoKeyType::try_from(key_type).unwrap_or(ProtoKeyType::Unspecified);
-            Ok(AuthEvents::AuthRequest(ChallengeRequest {
-                pubkey: parse_pubkey(kt, pubkey)?,
-            }))
-        }
-        UserAgentRequestPayload::AuthChallengeRequest(AuthChallengeRequest {
             pubkey,
             bootstrap_token: Some(token),
-            key_type,
+        } => Ok(AuthEvents::BootstrapAuthRequest(BootstrapAuthRequest {
-        }) => {
+            pubkey,
-            let kt = ProtoKeyType::try_from(key_type).unwrap_or(ProtoKeyType::Unspecified);
+            token,
-            Ok(AuthEvents::BootstrapAuthRequest(BootstrapAuthRequest {
+        })),
-                pubkey: parse_pubkey(kt, pubkey)?,
+        Request::AuthChallengeSolution { signature } => {
-                token,
-            }))
-        }
-        UserAgentRequestPayload::AuthChallengeSolution(AuthChallengeSolution { signature }) => {
             Ok(AuthEvents::ReceivedSolution(ChallengeSolution {
                 solution: signature,
             }))
@@ -99,10 +62,7 @@ pub async fn authenticate(props: &mut UserAgentConnection) -> Result<AuthPublicK
     loop {
         // `state` holds a mutable reference to `props` so we can't access it directly here
         let transport = state.context_mut().conn.transport.as_mut();
-        let Some(UserAgentRequest {
+        let Some(payload) = transport.recv().await else {
-            payload: Some(payload),
-        }) = transport.recv().await
-        else {
             return Err(Error::Transport);
         };
 

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

@@ -1,52 +1,16 @@
-use arbiter_proto::proto::user_agent::{
-    AuthChallenge, UserAgentResponse, user_agent_response::Payload as UserAgentResponsePayload,
-};
 use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl, update};
 use diesel_async::RunQueryDsl;
 use tracing::error;
 
 use super::Error;
 use crate::{
-    actors::{bootstrap::ConsumeToken, user_agent::UserAgentConnection},
+    actors::{
-    db::{models::KeyType, schema},
+        bootstrap::ConsumeToken,
+        user_agent::{AuthPublicKey, Response, UserAgentConnection},
+    },
+    db::schema,
 };
 
-/// Abstraction over Ed25519 / ECDSA-secp256k1 / RSA public keys used during the auth handshake.
-#[derive(Clone)]
-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 _;
-                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,
-        }
-    }
-}
-
 pub struct ChallengeRequest {
     pub pubkey: AuthPublicKey,
 }
@@ -57,7 +21,7 @@ pub struct BootstrapAuthRequest {
 }
 
 pub struct ChallengeContext {
-    pub challenge: AuthChallenge,
+    pub challenge_nonce: i32,
     pub key: AuthPublicKey,
 }
 
@@ -70,8 +34,8 @@ smlang::statemachine!(
     custom_error: true,
     transitions: {
         *Init + AuthRequest(ChallengeRequest) / async prepare_challenge = SentChallenge(ChallengeContext),
-        Init + BootstrapAuthRequest(BootstrapAuthRequest) [async verify_bootstrap_token] / provide_key_bootstrap = AuthOk(AuthPublicKey),
+        Init + BootstrapAuthRequest(BootstrapAuthRequest) / async verify_bootstrap_token = AuthOk(AuthPublicKey),
-        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) [async verify_solution] / provide_key = AuthOk(AuthPublicKey),
+        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) / async verify_solution = AuthOk(AuthPublicKey),
     }
 );
 
@@ -147,12 +111,71 @@ impl<'a> AuthContext<'a> {
 impl AuthStateMachineContext for AuthContext<'_> {
     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.conn
+            .transport
+            .send(Ok(Response::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::BootstrapperActorUnreachable
+            })?;
+
+        if !token_ok {
+            error!("Invalid bootstrap token provided");
+            return Err(Error::InvalidBootstrapToken);
+        }
+
+        register_key(&self.conn.db, &pubkey).await?;
+
+        self.conn
+                .transport
+                .send(Ok(Response::AuthOk))
+                .await
+                .map_err(|_| Error::Transport)?;
+
+        Ok(pubkey)
+    }
+
+    #[allow(missing_docs)]
+    #[allow(clippy::unused_unit)]
     async fn verify_solution(
-        &self,
+        &mut self,
-        ChallengeContext { challenge, key }: &ChallengeContext,
+        ChallengeContext { challenge_nonce, key }: &ChallengeContext,
-        ChallengeSolution { solution }: &ChallengeSolution,
+        ChallengeSolution { solution }: ChallengeSolution,
-    ) -> Result<bool, Self::Error> {
+    ) -> Result<AuthPublicKey, Self::Error> {
-        let formatted = arbiter_proto::format_challenge(challenge.nonce, &challenge.pubkey);
+        let formatted = arbiter_proto::format_challenge(*challenge_nonce, &key.to_stored_bytes());
 
         let valid = match key {
             AuthPublicKey::Ed25519(vk) => {
@@ -181,117 +204,14 @@ impl AuthStateMachineContext for AuthContext<'_> {
             }
         };
 
-        Ok(valid)
+        if valid {
-    }
+            self.conn
-
+                .transport
-    async fn prepare_challenge(
+                .send(Ok(Response::AuthOk))
-        &mut self,
+                .await
-        ChallengeRequest { pubkey }: ChallengeRequest,
+                .map_err(|_| Error::Transport)?;
-    ) -> Result<ChallengeContext, Self::Error> {
-        let stored_bytes = pubkey.to_stored_bytes();
-        let nonce = create_nonce(&self.conn.db, &stored_bytes).await?;
-
-        let challenge = AuthChallenge {
-            pubkey: stored_bytes,
-            nonce,
-        };
-
-        self.conn
-            .transport
-            .send(Ok(UserAgentResponse {
-                payload: Some(UserAgentResponsePayload::AuthChallenge(challenge.clone())),
-            }))
-            .await
-            .map_err(|e| {
-                error!(?e, "Failed to send auth challenge");
-                Error::Transport
-            })?;
-
-        Ok(ChallengeContext {
-            challenge,
-            key: pubkey,
-        })
-    }
-
-    #[allow(missing_docs)]
-    #[allow(clippy::result_unit_err)]
-    async fn verify_bootstrap_token(
-        &self,
-        BootstrapAuthRequest { pubkey, token }: &BootstrapAuthRequest,
-    ) -> Result<bool, Self::Error> {
-        let token_ok: bool = self
-            .conn
-            .actors
-            .bootstrapper
-            .ask(ConsumeToken {
-                token: token.clone(),
-            })
-            .await
-            .map_err(|e| {
-                error!(?e, "Failed to consume bootstrap token");
-                Error::BootstrapperActorUnreachable
-            })?;
-
-        if !token_ok {
-            error!("Invalid bootstrap token provided");
-            return Err(Error::InvalidBootstrapToken);
         }
 
-        register_key(&self.conn.db, pubkey).await?;
+        Ok(key.clone())
-
-        Ok(true)
-    }
-
-    fn provide_key_bootstrap(
-        &mut self,
-        event_data: BootstrapAuthRequest,
-    ) -> Result<AuthPublicKey, Self::Error> {
-        Ok(event_data.pubkey)
-    }
-
-    fn provide_key(
-        &mut self,
-        state_data: &ChallengeContext,
-        _: ChallengeSolution,
-    ) -> Result<AuthPublicKey, Self::Error> {
-        // ChallengeContext.key cannot be taken by value because smlang passes it by ref;
-        // we reconstruct stored bytes and return them wrapped in Ed25519 placeholder.
-        // Session uses only the raw bytes, so we carry them via a Vec<u8>.
-        // IMPORTANT: do NOT simplify this by storing the key type separately — the
-        // `AuthPublicKey` enum IS the source of truth for key bytes and type.
-        //
-        // smlang state-machine trait requires returning an owned value from `provide_key`,
-        // but `state_data` is only available by shared reference here.  We extract the
-        // stored bytes and re-wrap as the correct variant so the caller can call
-        // `to_stored_bytes()` / `key_type()` without losing information.
-        let bytes = state_data.challenge.pubkey.clone();
-        let key_type = state_data.key.key_type();
-        let rebuilt = match key_type {
-            crate::db::models::KeyType::Ed25519 => {
-                let arr: &[u8; 32] = bytes
-                    .as_slice()
-                    .try_into()
-                    .expect("ed25519 pubkey must be 32 bytes in challenge");
-                AuthPublicKey::Ed25519(
-                    ed25519_dalek::VerifyingKey::from_bytes(arr)
-                        .expect("key was already validated in parse_auth_event"),
-                )
-            }
-            crate::db::models::KeyType::EcdsaSecp256k1 => {
-                // bytes are SEC1 compressed (33 bytes produced by to_encoded_point(true))
-                AuthPublicKey::EcdsaSecp256k1(
-                    k256::ecdsa::VerifyingKey::from_sec1_bytes(&bytes)
-                        .expect("ecdsa key was already validated in parse_auth_event"),
-                )
-            }
-            crate::db::models::KeyType::Rsa => {
-                use rsa::pkcs8::DecodePublicKey as _;
-                AuthPublicKey::Rsa(
-                    rsa::RsaPublicKey::from_public_key_der(&bytes)
-                        .expect("rsa key was already validated in parse_auth_event"),
-                )
-            }
-        };
-        Ok(rebuilt)
     }
 }

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

@@ -1,19 +1,16 @@
-use arbiter_proto::{
+use alloy::primitives::Address;
-    proto::user_agent::{UserAgentRequest, UserAgentResponse},
+use arbiter_proto::{transport::Bi};
-    transport::Bi,
-};
 use kameo::actor::Spawn as _;
 use tracing::{error, info};
 
 use crate::{
-    actors::{GlobalActors, user_agent::session::UserAgentSession},
+    actors::{GlobalActors, evm, user_agent::session::UserAgentSession},
-    db::{self},
+    db::{self, models::KeyType}, evm::policies::{Grant, SpecificGrant},
+    evm::policies::SharedGrantSettings,
 };
 
 #[derive(Debug, thiserror::Error, PartialEq)]
 pub enum TransportResponseError {
-    #[error("Expected message with payload")]
-    MissingRequestPayload,
     #[error("Unexpected request payload")]
     UnexpectedRequestPayload,
     #[error("Invalid state for unseal encrypted key")]
@@ -30,8 +27,120 @@ pub enum TransportResponseError {
     ConnectionRegistrationFailed,
 }
 
-pub type Transport =
+/// Abstraction over Ed25519 / ECDSA-secp256k1 / RSA public keys used during the auth handshake.
-    Box<dyn Bi<UserAgentRequest, Result<UserAgentResponse, TransportResponseError>> + Send>;
+#[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 _;
+                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,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum UnsealError {
+    InvalidKey,
+    Unbootstrapped,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum BootstrapError {
+    AlreadyBootstrapped,
+    InvalidKey,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum VaultState {
+    Unbootstrapped,
+    Sealed,
+    Unsealed,
+}
+
+#[derive(Debug, Clone)]
+pub enum Request {
+    AuthChallengeRequest {
+        pubkey: AuthPublicKey,
+        bootstrap_token: Option<String>,
+    },
+    AuthChallengeSolution {
+        signature: Vec<u8>,
+    },
+    UnsealStart {
+        client_pubkey: x25519_dalek::PublicKey,
+    },
+    UnsealEncryptedKey {
+        nonce: Vec<u8>,
+        ciphertext: Vec<u8>,
+        associated_data: Vec<u8>,
+    },
+    BootstrapEncryptedKey {
+        nonce: Vec<u8>,
+        ciphertext: Vec<u8>,
+        associated_data: Vec<u8>,
+    },
+    QueryVaultState,
+    EvmWalletCreate,
+    EvmWalletList,
+    ClientConnectionResponse {
+        approved: bool,
+    },
+
+    ListGrants,
+    EvmGrantCreate {
+        client_id: i32,
+        shared: SharedGrantSettings,
+        specific: SpecificGrant,
+    },
+    EvmGrantDelete {
+        grant_id: i32,
+    },
+}
+
+#[derive(Debug)]
+pub enum Response {
+    AuthChallenge { nonce: i32 },
+    AuthOk,
+    UnsealStartResponse { server_pubkey: x25519_dalek::PublicKey },
+    UnsealResult(Result<(), UnsealError>),
+    BootstrapResult(Result<(), BootstrapError>),
+    VaultState(VaultState),
+    ClientConnectionRequest { pubkey: ed25519_dalek::VerifyingKey },
+    ClientConnectionCancel,
+    EvmWalletCreate(Result<(), evm::Error>),
+    EvmWalletList(Vec<Address>),
+
+    ListGrants(Vec<Grant<SpecificGrant>>),
+    EvmGrantCreate(Result<i32, evm::Error>),
+    EvmGrantDelete(Result<(), evm::Error>),
+}
+
+pub type Transport = Box<dyn Bi<Request, Result<Response, TransportResponseError>> + Send>;
 
 pub struct UserAgentConnection {
     db: db::DatabasePool,
@@ -52,6 +161,7 @@ impl UserAgentConnection {
 pub mod auth;
 pub mod session;
 
+#[tracing::instrument(skip(props))]
 pub async fn connect_user_agent(props: UserAgentConnection) {
     match auth::authenticate_and_create(props).await {
         Ok(session) => {

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

@@ -1,38 +1,18 @@
-use std::{ops::DerefMut, sync::Mutex};
+use ed25519_dalek::VerifyingKey;
-
+use kameo::{Actor, messages, prelude::Context};
-use arbiter_proto::proto::{
+use tokio::{select, sync::watch};
-    evm as evm_proto,
-    user_agent::{
-        SdkClientApproveRequest, SdkClientApproveResponse, SdkClientEntry,
-        SdkClientError as ProtoSdkClientError, SdkClientList, SdkClientListResponse,
-        SdkClientRevokeRequest, SdkClientRevokeResponse, UnsealEncryptedKey, UnsealResult,
-        UnsealStart, UnsealStartResponse, UserAgentRequest, UserAgentResponse,
-        sdk_client_approve_response, sdk_client_list_response, sdk_client_revoke_response,
-        user_agent_request::Payload as UserAgentRequestPayload,
-        user_agent_response::Payload as UserAgentResponsePayload,
-    },
-};
-use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
-use diesel::{ExpressionMethods as _, QueryDsl as _, dsl::insert_into};
-use diesel_async::RunQueryDsl as _;
-use kameo::{Actor, error::SendError, prelude::Context};
-use memsafe::MemSafe;
-use tokio::select;
 use tracing::{error, info};
-use x25519_dalek::{EphemeralSecret, PublicKey};
 
-use crate::{
+use crate::actors::{
-    actors::{
+    router::RegisterUserAgent,
-        evm::{Generate, ListWallets},
+    user_agent::{
-        keyholder::{self, TryUnseal},
+        Request, Response, TransportResponseError,
-        router::RegisterUserAgent,
+        UserAgentConnection,
-        user_agent::{TransportResponseError, UserAgentConnection},
     },
-    db::schema::program_client,
 };
 
 mod state;
-use state::{DummyContext, UnsealContext, UserAgentEvents, UserAgentStateMachine, UserAgentStates};
+use state::{DummyContext, UserAgentEvents, UserAgentStateMachine};
 
 // Error for consumption by other actors
 #[derive(Debug, thiserror::Error, PartialEq)]
@@ -49,6 +29,8 @@ pub struct UserAgentSession {
     state: UserAgentStateMachine<DummyContext>,
 }
 
+mod connection;
+
 impl UserAgentSession {
     pub(crate) fn new(props: UserAgentConnection) -> Self {
         Self {
@@ -57,31 +39,19 @@ impl UserAgentSession {
         }
     }
 
-    fn transition(&mut self, event: UserAgentEvents) -> Result<(), TransportResponseError> {
+    pub(super) async fn send_msg<Reply: kameo::Reply>(
-        self.state.process_event(event).map_err(|e| {
-            error!(?e, "State transition failed");
-            TransportResponseError::StateTransitionFailed
-        })?;
-        Ok(())
-    }
-
-    async fn send_msg<Reply: kameo::Reply>(
         &mut self,
-        msg: UserAgentResponsePayload,
+        msg: Response,
         _ctx: &mut Context<Self, Reply>,
     ) -> Result<(), Error> {
-        self.props
+        self.props.transport.send(Ok(msg)).await.map_err(|_| {
-            .transport
+            error!(
-            .send(Ok(response(msg)))
+                actor = "useragent",
-            .await
+                reason = "channel closed",
-            .map_err(|_| {
+                "send.failed"
-                error!(
+            );
-                    actor = "useragent",
+            Error::ConnectionLost
-                    reason = "channel closed",
+        })
-                    "send.failed"
-                );
-                Error::ConnectionLost
-            })
     }
 
     async fn expect_msg<Extractor, Msg, Reply>(
@@ -90,7 +60,7 @@ impl UserAgentSession {
         ctx: &mut Context<Self, Reply>,
     ) -> Result<Msg, Error>
     where
-        Extractor: FnOnce(UserAgentRequestPayload) -> Option<Msg>,
+        Extractor: FnOnce(Request) -> Option<Msg>,
         Reply: kameo::Reply,
     {
         let msg = self.props.transport.recv().await.ok_or_else(|| {
@@ -103,7 +73,7 @@ impl UserAgentSession {
             Error::ConnectionLost
         })?;
 
-        msg.payload.and_then(extractor).ok_or_else(|| {
+        extractor(msg).ok_or_else(|| {
             error!(
                 actor = "useragent",
                 reason = "unexpected message",
@@ -113,407 +83,60 @@ impl UserAgentSession {
             Error::UnexpectedMessage
         })
     }
-}
 
-impl UserAgentSession {
+    fn transition(&mut self, event: UserAgentEvents) -> Result<(), TransportResponseError> {
-    pub async fn process_transport_inbound(&mut self, req: UserAgentRequest) -> Output {
+        self.state.process_event(event).map_err(|e| {
-        let msg = req.payload.ok_or_else(|| {
+            error!(?e, "State transition failed");
-            error!(actor = "useragent", "Received message with no payload");
+            TransportResponseError::StateTransitionFailed
-            TransportResponseError::MissingRequestPayload
         })?;
-
+        Ok(())
-        match msg {
-            UserAgentRequestPayload::UnsealStart(unseal_start) => {
-                self.handle_unseal_request(unseal_start).await
-            }
-            UserAgentRequestPayload::UnsealEncryptedKey(unseal_encrypted_key) => {
-                self.handle_unseal_encrypted_key(unseal_encrypted_key).await
-            }
-            UserAgentRequestPayload::EvmWalletCreate(_) => self.handle_evm_wallet_create().await,
-            UserAgentRequestPayload::EvmWalletList(_) => self.handle_evm_wallet_list().await,
-            UserAgentRequestPayload::SdkClientApprove(req) => {
-                self.handle_sdk_client_approve(req).await
-            }
-            UserAgentRequestPayload::SdkClientRevoke(req) => {
-                self.handle_sdk_client_revoke(req).await
-            }
-            UserAgentRequestPayload::SdkClientList(_) => self.handle_sdk_client_list().await,
-            _ => Err(TransportResponseError::UnexpectedRequestPayload),
-        }
-    }
-}
-
-type Output = Result<UserAgentResponse, TransportResponseError>;
-
-fn response(payload: UserAgentResponsePayload) -> UserAgentResponse {
-    UserAgentResponse {
-        payload: Some(payload),
     }
 }
 
+#[messages]
 impl UserAgentSession {
-    async fn handle_unseal_request(&mut self, req: UnsealStart) -> Output {
+    // TODO: Think about refactoring it to state-machine based flow, as we already have one
-        let secret = EphemeralSecret::random();
+    #[message(ctx)]
-        let public_key = PublicKey::from(&secret);
+    pub async fn request_new_client_approval(
-
+        &mut self,
-        let client_pubkey_bytes: [u8; 32] = req
+        client_pubkey: VerifyingKey,
-            .client_pubkey
+        mut cancel_flag: watch::Receiver<()>,
-            .try_into()
+        ctx: &mut Context<Self, Result<bool, Error>>,
-            .map_err(|_| TransportResponseError::InvalidClientPubkeyLength)?;
+    ) -> Result<bool, Error> {
-
+        self.send_msg(
-        let client_public_key = PublicKey::from(client_pubkey_bytes);
+            Response::ClientConnectionRequest {
-
+                pubkey: client_pubkey,
-        self.transition(UserAgentEvents::UnsealRequest(UnsealContext {
-            secret: Mutex::new(Some(secret)),
-            client_public_key,
-        }))?;
-
-        Ok(response(UserAgentResponsePayload::UnsealStartResponse(
-            UnsealStartResponse {
-                server_pubkey: public_key.as_bytes().to_vec(),
             },
-        )))
+            ctx,
-    }
+        )
+        .await?;
 
-    async fn handle_unseal_encrypted_key(&mut self, req: UnsealEncryptedKey) -> Output {
+        let extractor = |msg| {
-        let UserAgentStates::WaitingForUnsealKey(unseal_context) = self.state.state() else {
+            if let Request::ClientConnectionResponse { approved } = msg {
-            error!("Received unseal encrypted key in invalid state");
+                Some(approved)
-            return Err(TransportResponseError::InvalidStateForUnsealEncryptedKey);
+            } else {
-        };
+                None
-        let ephemeral_secret = {
-            let mut secret_lock = unseal_context.secret.lock().unwrap();
-            let secret = secret_lock.take();
-            match secret {
-                Some(secret) => secret,
-                None => {
-                    drop(secret_lock);
-                    error!("Ephemeral secret already taken");
-                    self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                    return Ok(response(UserAgentResponsePayload::UnsealResult(
-                        UnsealResult::InvalidKey.into(),
-                    )));
-                }
             }
         };
 
-        let nonce = XNonce::from_slice(&req.nonce);
+        tokio::select! {
-
+            _ = cancel_flag.changed() => {
-        let shared_secret = ephemeral_secret.diffie_hellman(&unseal_context.client_public_key);
+                info!(actor = "useragent", "client connection approval cancelled");
-        let cipher = XChaCha20Poly1305::new(shared_secret.as_bytes().into());
+                self.send_msg(
-
+                    Response::ClientConnectionCancel,
-        let mut seal_key_buffer = MemSafe::new(req.ciphertext.clone()).unwrap();
+                    ctx,
-
+                ).await?;
-        let decryption_result = {
+                Ok(false)
-            let mut write_handle = seal_key_buffer.write().unwrap();
-            let write_handle = write_handle.deref_mut();
-            cipher.decrypt_in_place(nonce, &req.associated_data, write_handle)
-        };
-
-        match decryption_result {
-            Ok(_) => {
-                match self
-                    .props
-                    .actors
-                    .key_holder
-                    .ask(TryUnseal {
-                        seal_key_raw: seal_key_buffer,
-                    })
-                    .await
-                {
-                    Ok(_) => {
-                        info!("Successfully unsealed key with client-provided key");
-                        self.transition(UserAgentEvents::ReceivedValidKey)?;
-                        Ok(response(UserAgentResponsePayload::UnsealResult(
-                            UnsealResult::Success.into(),
-                        )))
-                    }
-                    Err(SendError::HandlerError(keyholder::Error::InvalidKey)) => {
-                        self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                        Ok(response(UserAgentResponsePayload::UnsealResult(
-                            UnsealResult::InvalidKey.into(),
-                        )))
-                    }
-                    Err(SendError::HandlerError(err)) => {
-                        error!(?err, "Keyholder failed to unseal key");
-                        self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                        Ok(response(UserAgentResponsePayload::UnsealResult(
-                            UnsealResult::InvalidKey.into(),
-                        )))
-                    }
-                    Err(err) => {
-                        error!(?err, "Failed to send unseal request to keyholder");
-                        self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                        Err(TransportResponseError::KeyHolderActorUnreachable)
-                    }
-                }
             }
-            Err(err) => {
+            result = self.expect_msg(extractor, ctx) => {
-                error!(?err, "Failed to decrypt unseal key");
+                let result = result?;
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                info!(actor = "useragent", "received client connection approval result: approved={}", result);
-                Ok(response(UserAgentResponsePayload::UnsealResult(
+                Ok(result)
-                    UnsealResult::InvalidKey.into(),
-                )))
             }
         }
     }
 }
 
-impl UserAgentSession {
-    async fn handle_evm_wallet_create(&mut self) -> Output {
-        use evm_proto::wallet_create_response::Result as CreateResult;
-
-        let result = match self.props.actors.evm.ask(Generate {}).await {
-            Ok(address) => CreateResult::Wallet(evm_proto::WalletEntry {
-                address: address.as_slice().to_vec(),
-            }),
-            Err(err) => CreateResult::Error(map_evm_error("wallet create", err).into()),
-        };
-
-        Ok(response(UserAgentResponsePayload::EvmWalletCreate(
-            evm_proto::WalletCreateResponse {
-                result: Some(result),
-            },
-        )))
-    }
-
-    async fn handle_evm_wallet_list(&mut self) -> Output {
-        use evm_proto::wallet_list_response::Result as ListResult;
-
-        let result = match self.props.actors.evm.ask(ListWallets {}).await {
-            Ok(wallets) => ListResult::Wallets(evm_proto::WalletList {
-                wallets: wallets
-                    .into_iter()
-                    .map(|addr| evm_proto::WalletEntry {
-                        address: addr.as_slice().to_vec(),
-                    })
-                    .collect(),
-            }),
-            Err(err) => ListResult::Error(map_evm_error("wallet list", err).into()),
-        };
-
-        Ok(response(UserAgentResponsePayload::EvmWalletList(
-            evm_proto::WalletListResponse {
-                result: Some(result),
-            },
-        )))
-    }
-}
-
-impl UserAgentSession {
-    async fn handle_sdk_client_approve(&mut self, req: SdkClientApproveRequest) -> Output {
-        use sdk_client_approve_response::Result as ApproveResult;
-
-        if req.pubkey.len() != 32 {
-            return Ok(response(UserAgentResponsePayload::SdkClientApprove(
-                SdkClientApproveResponse {
-                    result: Some(ApproveResult::Error(ProtoSdkClientError::Internal.into())),
-                },
-            )));
-        }
-
-        let now = std::time::SystemTime::now()
-            .duration_since(std::time::UNIX_EPOCH)
-            .unwrap_or_default()
-            .as_secs() as i32;
-
-        let mut conn = match self.props.db.get().await {
-            Ok(c) => c,
-            Err(e) => {
-                error!(?e, "Failed to get DB connection for sdk_client_approve");
-                return Ok(response(UserAgentResponsePayload::SdkClientApprove(
-                    SdkClientApproveResponse {
-                        result: Some(ApproveResult::Error(ProtoSdkClientError::Internal.into())),
-                    },
-                )));
-            }
-        };
-
-        let pubkey_bytes = req.pubkey.clone();
-        let insert_result = insert_into(program_client::table)
-            .values((
-                program_client::public_key.eq(&pubkey_bytes),
-                program_client::nonce.eq(1), // pre-incremented; challenge will use nonce=0
-                program_client::created_at.eq(now),
-                program_client::updated_at.eq(now),
-            ))
-            .execute(&mut conn)
-            .await;
-
-        match insert_result {
-            Ok(_) => {
-                match program_client::table
-                    .filter(program_client::public_key.eq(&pubkey_bytes))
-                    .order(program_client::id.desc())
-                    .select((
-                        program_client::id,
-                        program_client::public_key,
-                        program_client::created_at,
-                    ))
-                    .first::<(i32, Vec<u8>, i32)>(&mut conn)
-                    .await
-                {
-                    Ok((id, pubkey, created_at)) => Ok(response(
-                        UserAgentResponsePayload::SdkClientApprove(SdkClientApproveResponse {
-                            result: Some(ApproveResult::Client(SdkClientEntry {
-                                id,
-                                pubkey,
-                                created_at,
-                            })),
-                        }),
-                    )),
-                    Err(e) => {
-                        error!(?e, "Failed to fetch inserted SDK client");
-                        Ok(response(UserAgentResponsePayload::SdkClientApprove(
-                            SdkClientApproveResponse {
-                                result: Some(ApproveResult::Error(
-                                    ProtoSdkClientError::Internal.into(),
-                                )),
-                            },
-                        )))
-                    }
-                }
-            }
-            Err(diesel::result::Error::DatabaseError(
-                diesel::result::DatabaseErrorKind::UniqueViolation,
-                _,
-            )) => Ok(response(UserAgentResponsePayload::SdkClientApprove(
-                SdkClientApproveResponse {
-                    result: Some(ApproveResult::Error(
-                        ProtoSdkClientError::AlreadyExists.into(),
-                    )),
-                },
-            ))),
-            Err(e) => {
-                error!(?e, "Failed to insert SDK client");
-                Ok(response(UserAgentResponsePayload::SdkClientApprove(
-                    SdkClientApproveResponse {
-                        result: Some(ApproveResult::Error(ProtoSdkClientError::Internal.into())),
-                    },
-                )))
-            }
-        }
-    }
-
-    async fn handle_sdk_client_list(&mut self) -> Output {
-        let mut conn = match self.props.db.get().await {
-            Ok(c) => c,
-            Err(e) => {
-                error!(?e, "Failed to get DB connection for sdk_client_list");
-                return Ok(response(UserAgentResponsePayload::SdkClientList(
-                    SdkClientListResponse {
-                        result: Some(sdk_client_list_response::Result::Error(
-                            ProtoSdkClientError::Internal.into(),
-                        )),
-                    },
-                )));
-            }
-        };
-
-        match program_client::table
-            .select((
-                program_client::id,
-                program_client::public_key,
-                program_client::created_at,
-            ))
-            .load::<(i32, Vec<u8>, i32)>(&mut conn)
-            .await
-        {
-            Ok(rows) => Ok(response(UserAgentResponsePayload::SdkClientList(
-                SdkClientListResponse {
-                    result: Some(sdk_client_list_response::Result::Clients(SdkClientList {
-                        clients: rows
-                            .into_iter()
-                            .map(|(id, pubkey, created_at)| SdkClientEntry {
-                                id,
-                                pubkey,
-                                created_at,
-                            })
-                            .collect(),
-                    })),
-                },
-            ))),
-            Err(e) => {
-                error!(?e, "Failed to list SDK clients");
-                Ok(response(UserAgentResponsePayload::SdkClientList(
-                    SdkClientListResponse {
-                        result: Some(sdk_client_list_response::Result::Error(
-                            ProtoSdkClientError::Internal.into(),
-                        )),
-                    },
-                )))
-            }
-        }
-    }
-
-    async fn handle_sdk_client_revoke(&mut self, req: SdkClientRevokeRequest) -> Output {
-        use sdk_client_revoke_response::Result as RevokeResult;
-
-        let mut conn = match self.props.db.get().await {
-            Ok(c) => c,
-            Err(e) => {
-                error!(?e, "Failed to get DB connection for sdk_client_revoke");
-                return Ok(response(UserAgentResponsePayload::SdkClientRevoke(
-                    SdkClientRevokeResponse {
-                        result: Some(RevokeResult::Error(ProtoSdkClientError::Internal.into())),
-                    },
-                )));
-            }
-        };
-
-        match diesel::delete(program_client::table)
-            .filter(program_client::id.eq(req.client_id))
-            .execute(&mut conn)
-            .await
-        {
-            Ok(0) => Ok(response(UserAgentResponsePayload::SdkClientRevoke(
-                SdkClientRevokeResponse {
-                    result: Some(RevokeResult::Error(ProtoSdkClientError::NotFound.into())),
-                },
-            ))),
-            Ok(_) => Ok(response(UserAgentResponsePayload::SdkClientRevoke(
-                SdkClientRevokeResponse {
-                    result: Some(RevokeResult::Ok(())),
-                },
-            ))),
-            Err(diesel::result::Error::DatabaseError(
-                diesel::result::DatabaseErrorKind::ForeignKeyViolation,
-                _,
-            )) => Ok(response(UserAgentResponsePayload::SdkClientRevoke(
-                SdkClientRevokeResponse {
-                    result: Some(RevokeResult::Error(
-                        ProtoSdkClientError::HasRelatedData.into(),
-                    )),
-                },
-            ))),
-            Err(e) => {
-                error!(?e, "Failed to delete SDK client");
-                Ok(response(UserAgentResponsePayload::SdkClientRevoke(
-                    SdkClientRevokeResponse {
-                        result: Some(RevokeResult::Error(ProtoSdkClientError::Internal.into())),
-                    },
-                )))
-            }
-        }
-    }
-}
-
-fn map_evm_error<M>(op: &str, err: SendError<M, crate::actors::evm::Error>) -> evm_proto::EvmError {
-    use crate::actors::{evm::Error as EvmError, keyholder::Error as KhError};
-    match err {
-        SendError::HandlerError(EvmError::Keyholder(KhError::NotBootstrapped)) => {
-            evm_proto::EvmError::VaultSealed
-        }
-        SendError::HandlerError(err) => {
-            error!(?err, "EVM {op} failed");
-            evm_proto::EvmError::Internal
-        }
-        _ => {
-            error!("EVM actor unreachable during {op}");
-            evm_proto::EvmError::Internal
-        }
-    }
-}
-
 impl Actor for UserAgentSession {
     type Args = Self;
 

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

@@ -0,0 +1,351 @@
+use std::{ops::DerefMut, sync::Mutex};
+
+use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
+use kameo::error::SendError;
+use tracing::{error, info};
+use x25519_dalek::{EphemeralSecret, PublicKey};
+
+use crate::safe_cell::SafeCell;
+use crate::{
+    actors::{
+        evm::{
+            Generate, ListWallets, UseragentCreateGrant, UseragentDeleteGrant, UseragentListGrants,
+        },
+        keyholder::{self, Bootstrap, TryUnseal},
+        user_agent::{
+            BootstrapError, Request, Response, TransportResponseError, UnsealError, VaultState,
+            session::{
+                UserAgentSession,
+                state::{UnsealContext, UserAgentEvents, UserAgentStates},
+            },
+        },
+    },
+    safe_cell::SafeCellHandle as _,
+};
+
+impl UserAgentSession {
+    pub async fn process_transport_inbound(&mut self, req: Request) -> Output {
+        match req {
+            Request::UnsealStart { client_pubkey } => {
+                self.handle_unseal_request(client_pubkey).await
+            }
+            Request::UnsealEncryptedKey {
+                nonce,
+                ciphertext,
+                associated_data,
+            } => {
+                self.handle_unseal_encrypted_key(nonce, ciphertext, associated_data)
+                    .await
+            }
+            Request::BootstrapEncryptedKey {
+                nonce,
+                ciphertext,
+                associated_data,
+            } => {
+                self.handle_bootstrap_encrypted_key(nonce, ciphertext, associated_data)
+                    .await
+            }
+            Request::ListGrants => self.handle_grant_list().await,
+            Request::QueryVaultState => self.handle_query_vault_state().await,
+            Request::EvmWalletCreate => self.handle_evm_wallet_create().await,
+            Request::EvmWalletList => self.handle_evm_wallet_list().await,
+            Request::AuthChallengeRequest { .. }
+            | Request::AuthChallengeSolution { .. }
+            | Request::ClientConnectionResponse { .. } => {
+                Err(TransportResponseError::UnexpectedRequestPayload)
+            }
+            Request::EvmGrantCreate {
+                client_id,
+                shared,
+                specific,
+            } => self.handle_grant_create(client_id, shared, specific).await,
+            Request::EvmGrantDelete { grant_id } => self.handle_grant_delete(grant_id).await,
+        }
+    }
+}
+
+type Output = Result<Response, TransportResponseError>;
+
+impl UserAgentSession {
+    fn take_unseal_secret(
+        &mut self,
+    ) -> Result<(EphemeralSecret, PublicKey), TransportResponseError> {
+        let UserAgentStates::WaitingForUnsealKey(unseal_context) = self.state.state() else {
+            error!("Received encrypted key in invalid state");
+            return Err(TransportResponseError::InvalidStateForUnsealEncryptedKey);
+        };
+
+        let ephemeral_secret = {
+            let mut secret_lock = unseal_context.secret.lock().unwrap();
+            let secret = secret_lock.take();
+            match secret {
+                Some(secret) => secret,
+                None => {
+                    drop(secret_lock);
+                    error!("Ephemeral secret already taken");
+                    return Err(TransportResponseError::StateTransitionFailed);
+                }
+            }
+        };
+
+        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(())
+            }
+        }
+    }
+
+    async fn handle_unseal_request(&mut self, client_pubkey: x25519_dalek::PublicKey) -> Output {
+        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(Response::UnsealStartResponse {
+            server_pubkey: public_key,
+        })
+    }
+
+    async fn handle_unseal_encrypted_key(
+        &mut self,
+        nonce: Vec<u8>,
+        ciphertext: Vec<u8>,
+        associated_data: Vec<u8>,
+    ) -> Output {
+        let (ephemeral_secret, client_public_key) = match self.take_unseal_secret() {
+            Ok(values) => values,
+            Err(TransportResponseError::StateTransitionFailed) => {
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                return Ok(Response::UnsealResult(Err(UnsealError::InvalidKey)));
+            }
+            Err(err) => return Err(err),
+        };
+
+        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 Ok(Response::UnsealResult(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(Response::UnsealResult(Ok(())))
+            }
+            Err(SendError::HandlerError(keyholder::Error::InvalidKey)) => {
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                Ok(Response::UnsealResult(Err(UnsealError::InvalidKey)))
+            }
+            Err(SendError::HandlerError(err)) => {
+                error!(?err, "Keyholder failed to unseal key");
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                Ok(Response::UnsealResult(Err(UnsealError::InvalidKey)))
+            }
+            Err(err) => {
+                error!(?err, "Failed to send unseal request to keyholder");
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                Err(TransportResponseError::KeyHolderActorUnreachable)
+            }
+        }
+    }
+
+    async fn handle_bootstrap_encrypted_key(
+        &mut self,
+        nonce: Vec<u8>,
+        ciphertext: Vec<u8>,
+        associated_data: Vec<u8>,
+    ) -> Output {
+        let (ephemeral_secret, client_public_key) = match self.take_unseal_secret() {
+            Ok(values) => values,
+            Err(TransportResponseError::StateTransitionFailed) => {
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                return Ok(Response::BootstrapResult(Err(BootstrapError::InvalidKey)));
+            }
+            Err(err) => return Err(err),
+        };
+
+        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 Ok(Response::BootstrapResult(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(Response::BootstrapResult(Ok(())))
+            }
+            Err(SendError::HandlerError(keyholder::Error::AlreadyBootstrapped)) => {
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                Ok(Response::BootstrapResult(Err(
+                    BootstrapError::AlreadyBootstrapped,
+                )))
+            }
+            Err(SendError::HandlerError(err)) => {
+                error!(?err, "Keyholder failed to bootstrap vault");
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                Ok(Response::BootstrapResult(Err(BootstrapError::InvalidKey)))
+            }
+            Err(err) => {
+                error!(?err, "Failed to send bootstrap request to keyholder");
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                Err(TransportResponseError::KeyHolderActorUnreachable)
+            }
+        }
+    }
+}
+
+impl UserAgentSession {
+    async fn handle_query_vault_state(&mut self) -> Output {
+        use crate::actors::keyholder::{GetState, StateDiscriminants};
+
+        let vault_state = match self.props.actors.key_holder.ask(GetState {}).await {
+            Ok(StateDiscriminants::Unbootstrapped) => VaultState::Unbootstrapped,
+            Ok(StateDiscriminants::Sealed) => VaultState::Sealed,
+            Ok(StateDiscriminants::Unsealed) => VaultState::Unsealed,
+            Err(err) => {
+                error!(?err, actor = "useragent", "keyholder.query.failed");
+                return Err(TransportResponseError::KeyHolderActorUnreachable);
+            }
+        };
+
+        Ok(Response::VaultState(vault_state))
+    }
+}
+
+impl UserAgentSession {
+    async fn handle_evm_wallet_create(&mut self) -> Output {
+        let result = match self.props.actors.evm.ask(Generate {}).await {
+            Ok(_address) => return Ok(Response::EvmWalletCreate(Ok(()))),
+            Err(SendError::HandlerError(err)) => Err(err),
+            Err(err) => {
+                error!(?err, "EVM actor unreachable during wallet create");
+                return Err(TransportResponseError::KeyHolderActorUnreachable);
+            }
+        };
+        Ok(Response::EvmWalletCreate(result))
+    }
+
+    async fn handle_evm_wallet_list(&mut self) -> Output {
+        match self.props.actors.evm.ask(ListWallets {}).await {
+            Ok(wallets) => Ok(Response::EvmWalletList(wallets)),
+            Err(err) => {
+                error!(?err, "EVM wallet list failed");
+                Err(TransportResponseError::KeyHolderActorUnreachable)
+            }
+        }
+    }
+}
+
+impl UserAgentSession {
+    async fn handle_grant_list(&mut self) -> Output {
+        match self.props.actors.evm.ask(UseragentListGrants {}).await {
+            Ok(grants) => Ok(Response::ListGrants(grants)),
+            Err(err) => {
+                error!(?err, "EVM grant list failed");
+                Err(TransportResponseError::KeyHolderActorUnreachable)
+            }
+        }
+    }
+
+    async fn handle_grant_create(
+        &mut self,
+        client_id: i32,
+        basic: crate::evm::policies::SharedGrantSettings,
+        grant: crate::evm::policies::SpecificGrant,
+    ) -> Output {
+        match self
+            .props
+            .actors
+            .evm
+            .ask(UseragentCreateGrant {
+                client_id,
+                basic,
+                grant,
+            })
+            .await
+        {
+            Ok(grant_id) => Ok(Response::EvmGrantCreate(Ok(grant_id))),
+            Err(err) => {
+                error!(?err, "EVM grant create failed");
+                Err(TransportResponseError::KeyHolderActorUnreachable)
+            }
+        }
+    }
+
+    async fn handle_grant_delete(&mut self, grant_id: i32) -> Output {
+        match self
+            .props
+            .actors
+            .evm
+            .ask(UseragentDeleteGrant { grant_id })
+            .await
+        {
+            Ok(()) => Ok(Response::EvmGrantDelete(Ok(()))),
+            Err(err) => {
+                error!(?err, "EVM grant delete failed");
+                Err(TransportResponseError::KeyHolderActorUnreachable)
+            }
+        }
+    }
+}

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

@@ -8,7 +8,7 @@ use rcgen::{
     BasicConstraints, Certificate, CertificateParams, CertifiedIssuer, DistinguishedName, DnType,
     IsCa, Issuer, KeyPair, KeyUsagePurpose,
 };
-use rustls::pki_types::{pem::PemObject};
+use rustls::pki_types::pem::PemObject;
 use thiserror::Error;
 use tonic::transport::CertificateDer;
 
@@ -59,10 +59,7 @@ pub enum InitError {
 pub type PemCert = String;
 
 pub fn encode_cert_to_pem(cert: &CertificateDer) -> PemCert {
-    pem::encode_config(
+    pem::encode_config(&Pem::new("CERTIFICATE", cert.to_vec()), ENCODE_CONFIG)
-        &Pem::new("CERTIFICATE", cert.to_vec()),
-        ENCODE_CONFIG,
-    )
 }
 
 #[allow(unused)]

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

@@ -117,9 +117,7 @@ async fn check_shared_constraints(
     let now = Utc::now();
 
     // Validity window
-    if shared.valid_from.is_some_and(|t| now < t)
+    if shared.valid_from.is_some_and(|t| now < t) || shared.valid_until.is_some_and(|t| now > t) {
-        || shared.valid_until.is_some_and(|t| now > t)
-    {
         violations.push(EvalViolation::InvalidTime);
     }
 
@@ -127,9 +125,9 @@ async fn check_shared_constraints(
     let fee_exceeded = shared
         .max_gas_fee_per_gas
         .is_some_and(|cap| U256::from(context.max_fee_per_gas) > cap);
-    let priority_exceeded = shared.max_priority_fee_per_gas.is_some_and(|cap| {
+    let priority_exceeded = shared
-        U256::from(context.max_priority_fee_per_gas) > cap
+        .max_priority_fee_per_gas
-    });
+        .is_some_and(|cap| U256::from(context.max_priority_fee_per_gas) > cap);
     if fee_exceeded || priority_exceeded {
         violations.push(EvalViolation::GasLimitExceeded {
             max_gas_fee_per_gas: shared.max_gas_fee_per_gas,

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

@@ -66,6 +66,7 @@ pub enum EvalViolation {
 
 pub type DatabaseID = i32;
 
+#[derive(Debug)]
 pub struct Grant<PolicySettings> {
     pub id: DatabaseID,
     pub shared_grant_id: DatabaseID, // ID of the basic grant for shared-logic checks like rate limits and validity periods
@@ -73,7 +74,6 @@ pub struct Grant<PolicySettings> {
     pub settings: PolicySettings,
 }
 
-
 pub trait Policy: Sized {
     type Settings: Send + Sync + 'static + Into<SpecificGrant>;
     type Meaning: Display + std::fmt::Debug + Send + Sync + 'static + Into<SpecificMeaning>;
@@ -146,6 +146,7 @@ pub struct VolumeRateLimit {
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct SharedGrantSettings {
     pub wallet_id: i32,
+    pub client_id: i32,
     pub chain: ChainId,
 
     pub valid_from: Option<DateTime<Utc>>,
@@ -161,6 +162,7 @@ impl SharedGrantSettings {
     fn try_from_model(model: EvmBasicGrant) -> QueryResult<Self> {
         Ok(Self {
             wallet_id: model.wallet_id,
+            client_id: model.client_id,
             chain: model.chain_id as u64, // safe because chain_id is stored as i32 but is guaranteed to be a valid ChainId by the API when creating grants
             valid_from: model.valid_from.map(Into::into),
             valid_until: model.valid_until.map(Into::into),
@@ -198,6 +200,7 @@ impl SharedGrantSettings {
     }
 }
 
+#[derive(Debug, Clone)]
 pub enum SpecificGrant {
     EtherTransfer(ether_transfer::Settings),
     TokenTransfer(token_transfers::Settings),

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

@@ -51,9 +51,10 @@ impl From<Meaning> for SpecificMeaning {
 }
 
 // A grant for ether transfers, which can be scoped to specific target addresses and volume limits
+#[derive(Debug, Clone)]
 pub struct Settings {
-    target: Vec<Address>,
+    pub target: Vec<Address>,
-    limit: VolumeRateLimit,
+    pub limit: VolumeRateLimit,
 }
 
 impl From<Settings> for SpecificGrant {

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

@@ -9,9 +9,7 @@ use crate::db::{
     schema::{evm_basic_grant, evm_transaction_log},
 };
 use crate::evm::{
-    policies::{
+    policies::{EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings, VolumeRateLimit},
-        EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings, VolumeRateLimit,
-    },
     utils,
 };
 
@@ -76,6 +74,7 @@ fn shared() -> SharedGrantSettings {
         max_gas_fee_per_gas: None,
         max_priority_fee_per_gas: None,
         rate_limit: None,
+        client_id: CLIENT_ID,
     }
 }
 

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

@@ -58,10 +58,11 @@ impl From<Meaning> for SpecificMeaning {
 }
 
 // A grant for token transfers, which can be scoped to specific target addresses and volume limits
+#[derive(Debug, Clone)]
 pub struct Settings {
-    token_contract: Address,
+    pub token_contract: Address,
-    target: Option<Address>,
+    pub target: Option<Address>,
-    volume_limits: Vec<VolumeRateLimit>,
+    pub volume_limits: Vec<VolumeRateLimit>,
 }
 impl From<Settings> for SpecificGrant {
     fn from(val: Settings) -> SpecificGrant {

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

@@ -93,6 +93,7 @@ fn shared() -> SharedGrantSettings {
         max_gas_fee_per_gas: None,
         max_priority_fee_per_gas: None,
         rate_limit: None,
+        client_id: CLIENT_ID,
     }
 }
 
@@ -140,10 +141,18 @@ async fn evaluate_rejects_nonzero_eth_value() {
     let mut context = ctx(DAI, calldata);
     context.value = U256::from(1u64); // ETH attached to an ERC-20 call
 
-    let m = TokenTransfer::analyze(&EvalContext { value: U256::ZERO, ..context.clone() })
+    let m = TokenTransfer::analyze(&EvalContext {
+        value: U256::ZERO,
+        ..context.clone()
+    })
+    .unwrap();
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
+        .await
         .unwrap();
-    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn).await.unwrap();
+    assert!(
-    assert!(v.iter().any(|e| matches!(e, EvalViolation::InvalidTransactionType)));
+        v.iter()
+            .any(|e| matches!(e, EvalViolation::InvalidTransactionType))
+    );
 }
 
 #[tokio::test]
@@ -160,7 +169,9 @@ async fn evaluate_passes_any_recipient_when_no_restriction() {
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
     let m = TokenTransfer::analyze(&context).unwrap();
-    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn).await.unwrap();
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
+        .await
+        .unwrap();
     assert!(v.is_empty());
 }
 
@@ -178,7 +189,9 @@ async fn evaluate_passes_matching_restricted_recipient() {
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
     let m = TokenTransfer::analyze(&context).unwrap();
-    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn).await.unwrap();
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
+        .await
+        .unwrap();
     assert!(v.is_empty());
 }
 
@@ -196,8 +209,13 @@ async fn evaluate_rejects_wrong_restricted_recipient() {
     let calldata = transfer_calldata(OTHER, U256::from(100u64));
     let context = ctx(DAI, calldata);
     let m = TokenTransfer::analyze(&context).unwrap();
-    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn).await.unwrap();
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
-    assert!(v.iter().any(|e| matches!(e, EvalViolation::InvalidTarget { .. })));
+        .await
+        .unwrap();
+    assert!(
+        v.iter()
+            .any(|e| matches!(e, EvalViolation::InvalidTarget { .. }))
+    );
 }
 
 #[tokio::test]
@@ -207,7 +225,9 @@ async fn evaluate_passes_volume_within_limit() {
 
     let basic = insert_basic(&mut conn, false).await;
     let settings = make_settings(None, Some(1_000));
-    let grant_id = TokenTransfer::create_grant(&basic, &settings, &mut *conn).await.unwrap();
+    let grant_id = TokenTransfer::create_grant(&basic, &settings, &mut *conn)
+        .await
+        .unwrap();
 
     // Record a past transfer of 500 (within 1000 limit)
     use crate::db::{models::NewEvmTokenTransferLog, schema::evm_token_transfer_log};
@@ -224,12 +244,22 @@ async fn evaluate_passes_volume_within_limit() {
         .await
         .unwrap();
 
-    let grant = Grant { id: grant_id, shared_grant_id: basic.id, shared: shared(), settings };
+    let grant = Grant {
+        id: grant_id,
+        shared_grant_id: basic.id,
+        shared: shared(),
+        settings,
+    };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
     let m = TokenTransfer::analyze(&context).unwrap();
-    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn).await.unwrap();
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
-    assert!(!v.iter().any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded)));
+        .await
+        .unwrap();
+    assert!(
+        !v.iter()
+            .any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded))
+    );
 }
 
 #[tokio::test]
@@ -239,7 +269,9 @@ async fn evaluate_rejects_volume_over_limit() {
 
     let basic = insert_basic(&mut conn, false).await;
     let settings = make_settings(None, Some(1_000));
-    let grant_id = TokenTransfer::create_grant(&basic, &settings, &mut *conn).await.unwrap();
+    let grant_id = TokenTransfer::create_grant(&basic, &settings, &mut *conn)
+        .await
+        .unwrap();
 
     use crate::db::{models::NewEvmTokenTransferLog, schema::evm_token_transfer_log};
     insert_into(evm_token_transfer_log::table)
@@ -255,12 +287,22 @@ async fn evaluate_rejects_volume_over_limit() {
         .await
         .unwrap();
 
-    let grant = Grant { id: grant_id, shared_grant_id: basic.id, shared: shared(), settings };
+    let grant = Grant {
+        id: grant_id,
+        shared_grant_id: basic.id,
+        shared: shared(),
+        settings,
+    };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
     let m = TokenTransfer::analyze(&context).unwrap();
-    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn).await.unwrap();
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
-    assert!(v.iter().any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded)));
+        .await
+        .unwrap();
+    assert!(
+        v.iter()
+            .any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded))
+    );
 }
 
 #[tokio::test]
@@ -277,8 +319,13 @@ async fn evaluate_no_volume_limits_always_passes() {
     let calldata = transfer_calldata(RECIPIENT, U256::from(u64::MAX));
     let context = ctx(DAI, calldata);
     let m = TokenTransfer::analyze(&context).unwrap();
-    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn).await.unwrap();
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
-    assert!(!v.iter().any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded)));
+        .await
+        .unwrap();
+    assert!(
+        !v.iter()
+            .any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded))
+    );
 }
 
 // ── try_find_grant ───────────────────────────────────────────────────────
@@ -290,7 +337,9 @@ async fn try_find_grant_roundtrip() {
 
     let basic = insert_basic(&mut conn, false).await;
     let settings = make_settings(Some(RECIPIENT), Some(5_000));
-    TokenTransfer::create_grant(&basic, &settings, &mut *conn).await.unwrap();
+    TokenTransfer::create_grant(&basic, &settings, &mut *conn)
+        .await
+        .unwrap();
 
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let found = TokenTransfer::try_find_grant(&ctx(DAI, calldata), &mut *conn)
@@ -312,7 +361,9 @@ async fn try_find_grant_revoked_returns_none() {
 
     let basic = insert_basic(&mut conn, true).await;
     let settings = make_settings(None, None);
-    TokenTransfer::create_grant(&basic, &settings, &mut *conn).await.unwrap();
+    TokenTransfer::create_grant(&basic, &settings, &mut *conn)
+        .await
+        .unwrap();
 
     let calldata = transfer_calldata(RECIPIENT, U256::from(1u64));
     let found = TokenTransfer::try_find_grant(&ctx(DAI, calldata), &mut *conn)
@@ -328,7 +379,9 @@ async fn try_find_grant_unknown_token_returns_none() {
 
     let basic = insert_basic(&mut conn, false).await;
     let settings = make_settings(None, None);
-    TokenTransfer::create_grant(&basic, &settings, &mut *conn).await.unwrap();
+    TokenTransfer::create_grant(&basic, &settings, &mut *conn)
+        .await
+        .unwrap();
 
     // Query with a different token contract
     let calldata = transfer_calldata(RECIPIENT, U256::from(1u64));
@@ -355,9 +408,13 @@ async fn find_all_grants_excludes_revoked() {
 
     let settings = make_settings(None, Some(1_000));
     let active = insert_basic(&mut conn, false).await;
-    TokenTransfer::create_grant(&active, &settings, &mut *conn).await.unwrap();
+    TokenTransfer::create_grant(&active, &settings, &mut *conn)
+        .await
+        .unwrap();
     let revoked = insert_basic(&mut conn, true).await;
-    TokenTransfer::create_grant(&revoked, &settings, &mut *conn).await.unwrap();
+    TokenTransfer::create_grant(&revoked, &settings, &mut *conn)
+        .await
+        .unwrap();
 
     let all = TokenTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 1);
@@ -370,12 +427,17 @@ async fn find_all_grants_loads_volume_limits() {
 
     let basic = insert_basic(&mut conn, false).await;
     let settings = make_settings(None, Some(9_999));
-    TokenTransfer::create_grant(&basic, &settings, &mut *conn).await.unwrap();
+    TokenTransfer::create_grant(&basic, &settings, &mut *conn)
+        .await
+        .unwrap();
 
     let all = TokenTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 1);
     assert_eq!(all[0].settings.volume_limits.len(), 1);
-    assert_eq!(all[0].settings.volume_limits[0].max_volume, U256::from(9_999u64));
+    assert_eq!(
+        all[0].settings.volume_limits[0].max_volume,
+        U256::from(9_999u64)
+    );
 }
 
 #[tokio::test]
@@ -388,9 +450,13 @@ async fn find_all_grants_multiple_grants_batch_loaded() {
         .await
         .unwrap();
     let b2 = insert_basic(&mut conn, false).await;
-    TokenTransfer::create_grant(&b2, &make_settings(Some(RECIPIENT), Some(2_000)), &mut *conn)
+    TokenTransfer::create_grant(
-        .await
+        &b2,
-        .unwrap();
+        &make_settings(Some(RECIPIENT), Some(2_000)),
+        &mut *conn,
+    )
+    .await
+    .unwrap();
 
     let all = TokenTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 2);

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

@@ -1,14 +1,14 @@
 use std::sync::Mutex;
 
+use crate::safe_cell::{SafeCell, SafeCellHandle as _};
 use alloy::{
     consensus::SignableTransaction,
     network::{TxSigner, TxSignerSync},
-    primitives::{Address, ChainId, Signature, B256},
+    primitives::{Address, B256, ChainId, Signature},
     signers::{Error, Result, Signer, SignerSync, utils::secret_key_to_address},
 };
 use async_trait::async_trait;
-use k256::ecdsa::{self, signature::hazmat::PrehashSigner, RecoveryId, SigningKey};
+use k256::ecdsa::{self, RecoveryId, SigningKey, signature::hazmat::PrehashSigner};
-use memsafe::MemSafe;
 
 /// An Ethereum signer that stores its secp256k1 secret key inside a
 /// hardware-protected [`MemSafe`] cell.
@@ -20,7 +20,7 @@ use memsafe::MemSafe;
 /// Because [`MemSafe::read`] requires `&mut self` while the [`Signer`] trait
 /// requires `&self`, the cell is wrapped in a [`Mutex`].
 pub struct SafeSigner {
-    key: Mutex<MemSafe<SigningKey>>,
+    key: Mutex<SafeCell<SigningKey>>,
     address: Address,
     chain_id: Option<ChainId>,
 }
@@ -42,14 +42,13 @@ impl std::fmt::Debug for SafeSigner {
 /// rejection, but we retry to be correct).
 ///
 /// Returns the protected key bytes and the derived Ethereum address.
-pub fn generate(rng: &mut impl rand::Rng) -> (MemSafe<[u8; 32]>, Address) {
+pub fn generate(rng: &mut impl rand::Rng) -> (SafeCell<[u8; 32]>, Address) {
     loop {
-        let mut cell = MemSafe::new([0u8; 32]).expect("MemSafe allocation");
+        let mut cell = SafeCell::new_inline(|w: &mut [u8; 32]| {
-        {
+            rng.fill_bytes(w);
-            let mut w = cell.write().expect("MemSafe write");
+        });
-            rng.fill_bytes(w.as_mut());
+
-        }
+        let reader = cell.read();
-        let reader = cell.read().expect("MemSafe read");
         if let Ok(sk) = SigningKey::from_slice(reader.as_ref()) {
             let address = secret_key_to_address(&sk);
             drop(reader);
@@ -64,8 +63,8 @@ impl SafeSigner {
     /// The key bytes are read from protected memory, parsed as a secp256k1
     /// scalar, and immediately moved into a new [`MemSafe`] cell. The raw
     /// bytes are never exposed outside this function.
-    pub fn from_memsafe(mut cell: MemSafe<Vec<u8>>) -> Result<Self> {
+    pub fn from_cell(mut cell: SafeCell<Vec<u8>>) -> Result<Self> {
-        let reader = cell.read().map_err(Error::other)?;
+        let reader = cell.read();
         let sk = SigningKey::from_slice(reader.as_slice()).map_err(Error::other)?;
         drop(reader);
         Self::new(sk)
@@ -75,7 +74,7 @@ impl SafeSigner {
     /// memory region.
     pub fn new(key: SigningKey) -> Result<Self> {
         let address = secret_key_to_address(&key);
-        let cell = MemSafe::new(key).map_err(Error::other)?;
+        let cell = SafeCell::new(key);
         Ok(Self {
             key: Mutex::new(cell),
             address,
@@ -85,15 +84,12 @@ impl SafeSigner {
 
     fn sign_hash_inner(&self, hash: &B256) -> Result<Signature> {
         let mut cell = self.key.lock().expect("SafeSigner mutex poisoned");
-        let reader = cell.read().map_err(Error::other)?;
+        let reader = cell.read();
         let sig: (ecdsa::Signature, RecoveryId) = reader.sign_prehash(hash.as_ref())?;
         Ok(sig.into())
     }
 
-    fn sign_tx_inner(
+    fn sign_tx_inner(&self, tx: &mut dyn SignableTransaction<Signature>) -> Result<Signature> {
-        &self,
-        tx: &mut dyn SignableTransaction<Signature>,
-    ) -> Result<Signature> {
         if let Some(chain_id) = self.chain_id
             && !tx.set_chain_id_checked(chain_id)
         {
@@ -102,7 +98,8 @@ impl SafeSigner {
                 tx: tx.chain_id().unwrap(),
             });
         }
-        self.sign_hash_inner(&tx.signature_hash()).map_err(Error::other)
+        self.sign_hash_inner(&tx.signature_hash())
+            .map_err(Error::other)
     }
 }
 

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

@@ -0,0 +1,137 @@
+use arbiter_proto::{
+    proto::client::{
+        AuthChallenge as ProtoAuthChallenge,
+        AuthChallengeRequest as ProtoAuthChallengeRequest,
+        AuthChallengeSolution as ProtoAuthChallengeSolution, AuthOk as ProtoAuthOk,
+        ClientConnectError, ClientRequest, ClientResponse,
+        client_connect_error::Code as ProtoClientConnectErrorCode,
+        client_request::Payload as ClientRequestPayload,
+        client_response::Payload as ClientResponsePayload,
+    },
+    transport::{Bi, Error as TransportError},
+};
+use async_trait::async_trait;
+use futures::StreamExt as _;
+use tokio::sync::mpsc;
+use tonic::{Status, Streaming};
+
+use crate::actors::client::{
+    self, ClientError, ConnectErrorCode, Request as DomainRequest, Response as DomainResponse,
+};
+
+pub struct GrpcTransport {
+    sender: mpsc::Sender<Result<ClientResponse, Status>>,
+    receiver: Streaming<ClientRequest>,
+}
+
+impl GrpcTransport {
+    pub fn new(
+        sender: mpsc::Sender<Result<ClientResponse, Status>>,
+        receiver: Streaming<ClientRequest>,
+    ) -> Self {
+        Self { sender, receiver }
+    }
+
+    fn request_to_domain(request: ClientRequest) -> Result<DomainRequest, Status> {
+        match request.payload {
+            Some(ClientRequestPayload::AuthChallengeRequest(ProtoAuthChallengeRequest {
+                pubkey,
+            })) => Ok(DomainRequest::AuthChallengeRequest { pubkey }),
+            Some(ClientRequestPayload::AuthChallengeSolution(
+                ProtoAuthChallengeSolution { signature },
+            )) => Ok(DomainRequest::AuthChallengeSolution { signature }),
+            None => Err(Status::invalid_argument("Missing client request payload")),
+        }
+    }
+
+    fn response_to_proto(response: DomainResponse) -> ClientResponse {
+        let payload = match response {
+            DomainResponse::AuthChallenge { pubkey, nonce } => {
+                ClientResponsePayload::AuthChallenge(ProtoAuthChallenge { pubkey, nonce })
+            }
+            DomainResponse::AuthOk => ClientResponsePayload::AuthOk(ProtoAuthOk {}),
+            DomainResponse::ClientConnectError { code } => {
+                ClientResponsePayload::ClientConnectError(ClientConnectError {
+                    code: match code {
+                        ConnectErrorCode::Unknown => ProtoClientConnectErrorCode::Unknown,
+                        ConnectErrorCode::ApprovalDenied => {
+                            ProtoClientConnectErrorCode::ApprovalDenied
+                        }
+                        ConnectErrorCode::NoUserAgentsOnline => {
+                            ProtoClientConnectErrorCode::NoUserAgentsOnline
+                        }
+                    }
+                    .into(),
+                })
+            }
+        };
+
+        ClientResponse {
+            payload: Some(payload),
+        }
+    }
+
+    fn error_to_status(value: ClientError) -> Status {
+        match value {
+            ClientError::MissingRequestPayload | ClientError::UnexpectedRequestPayload => {
+                Status::invalid_argument("Expected message with payload")
+            }
+            ClientError::StateTransitionFailed => Status::internal("State machine error"),
+            ClientError::Auth(ref err) => auth_error_status(err),
+            ClientError::ConnectionRegistrationFailed => {
+                Status::internal("Connection registration failed")
+            }
+        }
+    }
+}
+
+#[async_trait]
+impl Bi<DomainRequest, Result<DomainResponse, ClientError>> for GrpcTransport {
+    async fn send(&mut self, item: Result<DomainResponse, ClientError>) -> Result<(), TransportError> {
+        let outbound = match item {
+            Ok(message) => Ok(Self::response_to_proto(message)),
+            Err(err) => Err(Self::error_to_status(err)),
+        };
+
+        self.sender
+            .send(outbound)
+            .await
+            .map_err(|_| TransportError::ChannelClosed)
+    }
+
+    async fn recv(&mut self) -> Option<DomainRequest> {
+        match self.receiver.next().await {
+            Some(Ok(item)) => match Self::request_to_domain(item) {
+                Ok(request) => Some(request),
+                Err(status) => {
+                    let _ = self.sender.send(Err(status)).await;
+                    None
+                }
+            },
+            Some(Err(error)) => {
+                tracing::error!(error = ?error, "grpc client recv failed; closing stream");
+                None
+            }
+            None => None,
+        }
+    }
+}
+
+fn auth_error_status(value: &client::auth::Error) -> Status {
+    use client::auth::Error;
+
+    match value {
+        Error::UnexpectedMessagePayload | Error::InvalidClientPubkeyLength => {
+            Status::invalid_argument(value.to_string())
+        }
+        Error::InvalidAuthPubkeyEncoding => {
+            Status::invalid_argument("Failed to convert pubkey to VerifyingKey")
+        }
+        Error::InvalidChallengeSolution => Status::unauthenticated(value.to_string()),
+        Error::ApproveError(_) => Status::permission_denied(value.to_string()),
+        Error::Transport => Status::internal("Transport error"),
+        Error::DatabasePoolUnavailable => Status::internal("Database pool error"),
+        Error::DatabaseOperationFailed => Status::internal("Database error"),
+        Error::InternalError => Status::internal("Internal error"),
+    }
+}

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

@@ -0,0 +1,65 @@
+
+use arbiter_proto::proto::{
+    client::{ClientRequest, ClientResponse},
+    user_agent::{UserAgentRequest, UserAgentResponse},
+};
+use tokio::sync::mpsc;
+use tokio_stream::wrappers::ReceiverStream;
+use tonic::{Request, Response, Status, async_trait};
+use tracing::info;
+
+use crate::{
+    DEFAULT_CHANNEL_SIZE,
+    actors::{client::{ClientConnection, connect_client}, user_agent::{UserAgentConnection, connect_user_agent}},
+};
+
+pub mod client;
+pub mod user_agent;
+
+#[async_trait]
+impl arbiter_proto::proto::arbiter_service_server::ArbiterService for super::Server {
+    type UserAgentStream = ReceiverStream<Result<UserAgentResponse, Status>>;
+    type ClientStream = ReceiverStream<Result<ClientResponse, Status>>;
+
+    #[tracing::instrument(level = "debug", skip(self))]
+    async fn client(
+        &self,
+        request: Request<tonic::Streaming<ClientRequest>>,
+    ) -> Result<Response<Self::ClientStream>, Status> {
+        let req_stream = request.into_inner();
+        let (tx, rx) = mpsc::channel(DEFAULT_CHANNEL_SIZE);
+
+        let transport = client::GrpcTransport::new(tx, req_stream);
+        let props = ClientConnection::new(
+            self.context.db.clone(),
+            Box::new(transport),
+            self.context.actors.clone(),
+        );
+        tokio::spawn(connect_client(props));
+
+        info!(event = "connection established", "grpc.client");
+
+        Ok(Response::new(ReceiverStream::new(rx)))
+    }
+
+    #[tracing::instrument(level = "debug", skip(self))]
+    async fn user_agent(
+        &self,
+        request: Request<tonic::Streaming<UserAgentRequest>>,
+    ) -> Result<Response<Self::UserAgentStream>, Status> {
+        let req_stream = request.into_inner();
+        let (tx, rx) = mpsc::channel(DEFAULT_CHANNEL_SIZE);
+
+        let transport = user_agent::GrpcTransport::new(tx, req_stream);
+        let props = UserAgentConnection::new(
+            self.context.db.clone(),
+            self.context.actors.clone(),
+            Box::new(transport),
+        );
+        tokio::spawn(connect_user_agent(props));
+
+        info!(event = "connection established", "grpc.user_agent");
+
+        Ok(Response::new(ReceiverStream::new(rx)))
+    }
+}

server/crates/arbiter-server/src/grpc/user_agent.rs

@@ -0,0 +1,509 @@
+use arbiter_proto::{
+    proto::{
+        self,
+        evm::{
+            EtherTransferSettings as ProtoEtherTransferSettings, EvmError as ProtoEvmError,
+            EvmGrantCreateRequest, EvmGrantCreateResponse, EvmGrantDeleteRequest,
+            EvmGrantDeleteResponse, EvmGrantList, EvmGrantListResponse, GrantEntry,
+            SharedSettings as ProtoSharedSettings, SpecificGrant as ProtoSpecificGrant,
+            TokenTransferSettings as ProtoTokenTransferSettings,
+            VolumeRateLimit as ProtoVolumeRateLimit, WalletCreateResponse, WalletEntry, WalletList,
+            WalletListResponse, evm_grant_create_response::Result as EvmGrantCreateResult,
+            evm_grant_delete_response::Result as EvmGrantDeleteResult,
+            evm_grant_list_response::Result as EvmGrantListResult,
+            specific_grant::Grant as ProtoSpecificGrantType,
+            wallet_create_response::Result as WalletCreateResult,
+            wallet_list_response::Result as WalletListResult,
+        },
+        user_agent::{
+            AuthChallenge as ProtoAuthChallenge, AuthChallengeRequest as ProtoAuthChallengeRequest,
+            AuthChallengeSolution as ProtoAuthChallengeSolution, AuthOk as ProtoAuthOk,
+            BootstrapEncryptedKey as ProtoBootstrapEncryptedKey,
+            BootstrapResult as ProtoBootstrapResult, ClientConnectionCancel,
+            ClientConnectionRequest, ClientConnectionResponse, KeyType as ProtoKeyType,
+            UnsealEncryptedKey as ProtoUnsealEncryptedKey, UnsealResult as ProtoUnsealResult,
+            UnsealStart, UnsealStartResponse, UserAgentRequest, UserAgentResponse,
+            VaultState as ProtoVaultState, user_agent_request::Payload as UserAgentRequestPayload,
+            user_agent_response::Payload as UserAgentResponsePayload,
+        },
+    },
+    transport::{Bi, Error as TransportError},
+};
+use async_trait::async_trait;
+use futures::StreamExt as _;
+use prost_types::Timestamp;
+use tokio::sync::mpsc;
+use tonic::{Status, Streaming};
+
+use crate::{
+    actors::user_agent::{
+        self, AuthPublicKey, BootstrapError, Request as DomainRequest, Response as DomainResponse,
+        TransportResponseError, UnsealError, VaultState,
+    },
+    evm::{
+        policies::{Grant, SpecificGrant},
+        policies::{
+            SharedGrantSettings, TransactionRateLimit, VolumeRateLimit, ether_transfer,
+            token_transfers,
+        },
+    },
+};
+use alloy::primitives::{Address, U256};
+use chrono::{DateTime, TimeZone, Utc};
+
+pub struct GrpcTransport {
+    sender: mpsc::Sender<Result<UserAgentResponse, Status>>,
+    receiver: Streaming<UserAgentRequest>,
+}
+
+impl GrpcTransport {
+    pub fn new(
+        sender: mpsc::Sender<Result<UserAgentResponse, Status>>,
+        receiver: Streaming<UserAgentRequest>,
+    ) -> Self {
+        Self { sender, receiver }
+    }
+
+    fn request_to_domain(request: UserAgentRequest) -> Result<DomainRequest, Status> {
+        match request.payload {
+            Some(UserAgentRequestPayload::AuthChallengeRequest(ProtoAuthChallengeRequest {
+                pubkey,
+                bootstrap_token,
+                key_type,
+            })) => Ok(DomainRequest::AuthChallengeRequest {
+                pubkey: parse_auth_pubkey(key_type, pubkey)?,
+                bootstrap_token,
+            }),
+            Some(UserAgentRequestPayload::AuthChallengeSolution(ProtoAuthChallengeSolution {
+                signature,
+            })) => Ok(DomainRequest::AuthChallengeSolution { signature }),
+            Some(UserAgentRequestPayload::UnsealStart(UnsealStart { client_pubkey })) => {
+                let client_pubkey: [u8; 32] = client_pubkey
+                    .as_slice()
+                    .try_into()
+                    .map_err(|_| Status::invalid_argument("client_pubkey must be 32 bytes"))?;
+                Ok(DomainRequest::UnsealStart {
+                    client_pubkey: x25519_dalek::PublicKey::from(client_pubkey),
+                })
+            }
+            Some(UserAgentRequestPayload::UnsealEncryptedKey(ProtoUnsealEncryptedKey {
+                nonce,
+                ciphertext,
+                associated_data,
+            })) => Ok(DomainRequest::UnsealEncryptedKey {
+                nonce,
+                ciphertext,
+                associated_data,
+            }),
+            Some(UserAgentRequestPayload::BootstrapEncryptedKey(ProtoBootstrapEncryptedKey {
+                nonce,
+                ciphertext,
+                associated_data,
+            })) => Ok(DomainRequest::BootstrapEncryptedKey {
+                nonce,
+                ciphertext,
+                associated_data,
+            }),
+            Some(UserAgentRequestPayload::QueryVaultState(_)) => Ok(DomainRequest::QueryVaultState),
+            Some(UserAgentRequestPayload::EvmWalletCreate(_)) => Ok(DomainRequest::EvmWalletCreate),
+            Some(UserAgentRequestPayload::EvmWalletList(_)) => Ok(DomainRequest::EvmWalletList),
+            Some(UserAgentRequestPayload::ClientConnectionResponse(ClientConnectionResponse {
+                approved,
+            })) => Ok(DomainRequest::ClientConnectionResponse { approved }),
+
+            Some(UserAgentRequestPayload::EvmGrantList(_)) => Ok(DomainRequest::ListGrants),
+            Some(UserAgentRequestPayload::EvmGrantCreate(EvmGrantCreateRequest {
+                client_id,
+                shared,
+                specific,
+            })) => {
+                let shared = parse_shared_settings(client_id, shared)?;
+                let specific = parse_specific_grant(specific)?;
+                Ok(DomainRequest::EvmGrantCreate {
+                    client_id,
+                    shared,
+                    specific,
+                })
+            }
+            Some(UserAgentRequestPayload::EvmGrantDelete(EvmGrantDeleteRequest { grant_id })) => {
+                Ok(DomainRequest::EvmGrantDelete { grant_id })
+            }
+            None => Err(Status::invalid_argument(
+                "Missing user-agent request payload",
+            )),
+        }
+    }
+
+    fn response_to_proto(response: DomainResponse) -> UserAgentResponse {
+        let payload = match response {
+            DomainResponse::AuthChallenge { nonce } => {
+                UserAgentResponsePayload::AuthChallenge(ProtoAuthChallenge {
+                    pubkey: Vec::new(),
+                    nonce,
+                })
+            }
+            DomainResponse::AuthOk => UserAgentResponsePayload::AuthOk(ProtoAuthOk {}),
+            DomainResponse::UnsealStartResponse { server_pubkey } => {
+                UserAgentResponsePayload::UnsealStartResponse(UnsealStartResponse {
+                    server_pubkey: server_pubkey.as_bytes().to_vec(),
+                })
+            }
+            DomainResponse::UnsealResult(result) => UserAgentResponsePayload::UnsealResult(
+                match result {
+                    Ok(()) => ProtoUnsealResult::Success,
+                    Err(UnsealError::InvalidKey) => ProtoUnsealResult::InvalidKey,
+                    Err(UnsealError::Unbootstrapped) => ProtoUnsealResult::Unbootstrapped,
+                }
+                .into(),
+            ),
+            DomainResponse::BootstrapResult(result) => UserAgentResponsePayload::BootstrapResult(
+                match result {
+                    Ok(()) => ProtoBootstrapResult::Success,
+                    Err(BootstrapError::AlreadyBootstrapped) => {
+                        ProtoBootstrapResult::AlreadyBootstrapped
+                    }
+                    Err(BootstrapError::InvalidKey) => ProtoBootstrapResult::InvalidKey,
+                }
+                .into(),
+            ),
+            DomainResponse::VaultState(state) => UserAgentResponsePayload::VaultState(
+                match state {
+                    VaultState::Unbootstrapped => ProtoVaultState::Unbootstrapped,
+                    VaultState::Sealed => ProtoVaultState::Sealed,
+                    VaultState::Unsealed => ProtoVaultState::Unsealed,
+                }
+                .into(),
+            ),
+            DomainResponse::ClientConnectionRequest { pubkey } => {
+                UserAgentResponsePayload::ClientConnectionRequest(ClientConnectionRequest {
+                    pubkey: pubkey.to_bytes().to_vec(),
+                })
+            }
+            DomainResponse::ClientConnectionCancel => {
+                UserAgentResponsePayload::ClientConnectionCancel(ClientConnectionCancel {})
+            }
+            DomainResponse::EvmWalletCreate(result) => {
+                UserAgentResponsePayload::EvmWalletCreate(WalletCreateResponse {
+                    result: Some(match result {
+                        Ok(()) => WalletCreateResult::Wallet(WalletEntry {
+                            address: Vec::new(),
+                        }),
+                        Err(_) => WalletCreateResult::Error(ProtoEvmError::Internal.into()),
+                    }),
+                })
+            }
+            DomainResponse::EvmWalletList(wallets) => {
+                UserAgentResponsePayload::EvmWalletList(WalletListResponse {
+                    result: Some(WalletListResult::Wallets(WalletList {
+                        wallets: wallets
+                            .into_iter()
+                            .map(|addr| WalletEntry {
+                                address: addr.as_slice().to_vec(),
+                            })
+                            .collect(),
+                    })),
+                })
+            }
+            DomainResponse::ListGrants(grants) => {
+                UserAgentResponsePayload::EvmGrantList(EvmGrantListResponse {
+                    result: Some(EvmGrantListResult::Grants(EvmGrantList {
+                        grants: grants.into_iter().map(grant_to_proto).collect(),
+                    })),
+                })
+            }
+            DomainResponse::EvmGrantCreate(result) => {
+                UserAgentResponsePayload::EvmGrantCreate(EvmGrantCreateResponse {
+                    result: Some(match result {
+                        Ok(grant_id) => EvmGrantCreateResult::GrantId(grant_id),
+                        Err(_) => EvmGrantCreateResult::Error(ProtoEvmError::Internal.into()),
+                    }),
+                })
+            }
+            DomainResponse::EvmGrantDelete(result) => {
+                UserAgentResponsePayload::EvmGrantDelete(EvmGrantDeleteResponse {
+                    result: Some(match result {
+                        Ok(()) => EvmGrantDeleteResult::Ok(()),
+                        Err(_) => EvmGrantDeleteResult::Error(ProtoEvmError::Internal.into()),
+                    }),
+                })
+            }
+        };
+
+        UserAgentResponse {
+            payload: Some(payload),
+        }
+    }
+
+    fn error_to_status(value: TransportResponseError) -> Status {
+        match value {
+            TransportResponseError::UnexpectedRequestPayload => {
+                Status::invalid_argument("Expected message with payload")
+            }
+            TransportResponseError::InvalidStateForUnsealEncryptedKey => {
+                Status::failed_precondition("Invalid state for unseal encrypted key")
+            }
+            TransportResponseError::InvalidClientPubkeyLength => {
+                Status::invalid_argument("client_pubkey must be 32 bytes")
+            }
+            TransportResponseError::StateTransitionFailed => {
+                Status::internal("State machine error")
+            }
+            TransportResponseError::KeyHolderActorUnreachable => {
+                Status::internal("Vault is not available")
+            }
+            TransportResponseError::Auth(ref err) => auth_error_status(err),
+            TransportResponseError::ConnectionRegistrationFailed => {
+                Status::internal("Failed registering connection")
+            }
+        }
+    }
+}
+
+#[async_trait]
+impl Bi<DomainRequest, Result<DomainResponse, TransportResponseError>> for GrpcTransport {
+    async fn send(
+        &mut self,
+        item: Result<DomainResponse, TransportResponseError>,
+    ) -> Result<(), TransportError> {
+        let outbound = match item {
+            Ok(message) => Ok(Self::response_to_proto(message)),
+            Err(err) => Err(Self::error_to_status(err)),
+        };
+
+        self.sender
+            .send(outbound)
+            .await
+            .map_err(|_| TransportError::ChannelClosed)
+    }
+
+    async fn recv(&mut self) -> Option<DomainRequest> {
+        match self.receiver.next().await {
+            Some(Ok(item)) => match Self::request_to_domain(item) {
+                Ok(request) => Some(request),
+                Err(status) => {
+                    let _ = self.sender.send(Err(status)).await;
+                    None
+                }
+            },
+            Some(Err(error)) => {
+                tracing::error!(error = ?error, "grpc user-agent recv failed; closing stream");
+                None
+            }
+            None => None,
+        }
+    }
+}
+
+fn grant_to_proto(grant: Grant<SpecificGrant>) -> proto::evm::GrantEntry {
+    GrantEntry {
+        id: grant.id,
+        specific: Some(match grant.settings {
+            SpecificGrant::EtherTransfer(settings) => ProtoSpecificGrant {
+                grant: Some(ProtoSpecificGrantType::EtherTransfer(
+                    ProtoEtherTransferSettings {
+                        targets: settings
+                            .target
+                            .into_iter()
+                            .map(|addr| addr.as_slice().to_vec())
+                            .collect(),
+                        limit: Some(proto::evm::VolumeRateLimit {
+                            max_volume: settings.limit.max_volume.to_be_bytes_vec(),
+                            window_secs: settings.limit.window.num_seconds(),
+                        }),
+                    },
+                )),
+            },
+            SpecificGrant::TokenTransfer(settings) => ProtoSpecificGrant {
+                grant: Some(ProtoSpecificGrantType::TokenTransfer(
+                    ProtoTokenTransferSettings {
+                        token_contract: settings.token_contract.as_slice().to_vec(),
+                        target: settings.target.map(|addr| addr.as_slice().to_vec()),
+                        volume_limits: settings
+                            .volume_limits
+                            .into_iter()
+                            .map(|vrl| proto::evm::VolumeRateLimit {
+                                max_volume: vrl.max_volume.to_be_bytes_vec(),
+                                window_secs: vrl.window.num_seconds(),
+                            })
+                            .collect(),
+                    },
+                )),
+            },
+        }),
+        client_id: grant.shared.client_id,
+        shared: Some(proto::evm::SharedSettings {
+            wallet_id: grant.shared.wallet_id,
+            chain_id: grant.shared.chain,
+            valid_from: grant.shared.valid_from.map(|dt| Timestamp {
+                seconds: dt.timestamp(),
+                nanos: 0,
+            }),
+            valid_until: grant.shared.valid_until.map(|dt| Timestamp {
+                seconds: dt.timestamp(),
+                nanos: 0,
+            }),
+            max_gas_fee_per_gas: grant
+                .shared
+                .max_gas_fee_per_gas
+                .map(|fee| fee.to_be_bytes_vec()),
+            max_priority_fee_per_gas: grant
+                .shared
+                .max_priority_fee_per_gas
+                .map(|fee| fee.to_be_bytes_vec()),
+            rate_limit: grant
+                .shared
+                .rate_limit
+                .map(|limit| proto::evm::TransactionRateLimit {
+                    count: limit.count,
+                    window_secs: limit.window.num_seconds(),
+                }),
+        }),
+    }
+}
+
+fn parse_volume_rate_limit(vrl: ProtoVolumeRateLimit) -> Result<VolumeRateLimit, Status> {
+    Ok(VolumeRateLimit {
+        max_volume: U256::from_be_slice(&vrl.max_volume),
+        window: chrono::Duration::seconds(vrl.window_secs),
+    })
+}
+
+fn parse_shared_settings(
+    client_id: i32,
+    proto: Option<ProtoSharedSettings>,
+) -> Result<SharedGrantSettings, Status> {
+    let s = proto.ok_or_else(|| Status::invalid_argument("missing shared settings"))?;
+    let parse_u256 = |b: Vec<u8>| -> Result<U256, Status> {
+        if b.is_empty() {
+            Err(Status::invalid_argument("U256 bytes must not be empty"))
+        } else {
+            Ok(U256::from_be_slice(&b))
+        }
+    };
+    let parse_ts = |ts: prost_types::Timestamp| -> Result<DateTime<Utc>, Status> {
+        Utc.timestamp_opt(ts.seconds, ts.nanos as u32)
+            .single()
+            .ok_or_else(|| Status::invalid_argument("invalid timestamp"))
+    };
+    Ok(SharedGrantSettings {
+        wallet_id: s.wallet_id,
+        client_id,
+        chain: s.chain_id,
+        valid_from: s.valid_from.map(parse_ts).transpose()?,
+        valid_until: s.valid_until.map(parse_ts).transpose()?,
+        max_gas_fee_per_gas: s.max_gas_fee_per_gas.map(parse_u256).transpose()?,
+        max_priority_fee_per_gas: s.max_priority_fee_per_gas.map(parse_u256).transpose()?,
+        rate_limit: s.rate_limit.map(|rl| TransactionRateLimit {
+            count: rl.count,
+            window: chrono::Duration::seconds(rl.window_secs),
+        }),
+    })
+}
+
+fn parse_specific_grant(proto: Option<proto::evm::SpecificGrant>) -> Result<SpecificGrant, Status> {
+    use proto::evm::specific_grant::Grant as ProtoGrant;
+    let g = proto
+        .and_then(|sg| sg.grant)
+        .ok_or_else(|| Status::invalid_argument("missing specific grant"))?;
+    match g {
+        ProtoGrant::EtherTransfer(s) => {
+            let limit = parse_volume_rate_limit(
+                s.limit
+                    .ok_or_else(|| Status::invalid_argument("missing ether transfer limit"))?,
+            )?;
+            let target = s
+                .targets
+                .into_iter()
+                .map(|b| {
+                    if b.len() == 20 {
+                        Ok(Address::from_slice(&b))
+                    } else {
+                        Err(Status::invalid_argument(
+                            "ether transfer target must be 20 bytes",
+                        ))
+                    }
+                })
+                .collect::<Result<Vec<_>, _>>()?;
+            Ok(SpecificGrant::EtherTransfer(ether_transfer::Settings {
+                target,
+                limit,
+            }))
+        }
+        ProtoGrant::TokenTransfer(s) => {
+            if s.token_contract.len() != 20 {
+                return Err(Status::invalid_argument("token_contract must be 20 bytes"));
+            }
+            let target = s
+                .target
+                .map(|b| {
+                    if b.len() == 20 {
+                        Ok(Address::from_slice(&b))
+                    } else {
+                        Err(Status::invalid_argument(
+                            "token transfer target must be 20 bytes",
+                        ))
+                    }
+                })
+                .transpose()?;
+            let volume_limits = s
+                .volume_limits
+                .into_iter()
+                .map(parse_volume_rate_limit)
+                .collect::<Result<Vec<_>, _>>()?;
+            Ok(SpecificGrant::TokenTransfer(token_transfers::Settings {
+                token_contract: Address::from_slice(&s.token_contract),
+                target,
+                volume_limits,
+            }))
+        }
+    }
+}
+
+fn parse_auth_pubkey(key_type: i32, pubkey: Vec<u8>) -> Result<AuthPublicKey, Status> {
+    match ProtoKeyType::try_from(key_type).unwrap_or(ProtoKeyType::Unspecified) {
+        ProtoKeyType::Unspecified | ProtoKeyType::Ed25519 => {
+            let bytes: [u8; 32] = pubkey
+                .as_slice()
+                .try_into()
+                .map_err(|_| Status::invalid_argument("invalid Ed25519 public key length"))?;
+            let key = ed25519_dalek::VerifyingKey::from_bytes(&bytes)
+                .map_err(|_| Status::invalid_argument("invalid Ed25519 public key encoding"))?;
+            Ok(AuthPublicKey::Ed25519(key))
+        }
+        ProtoKeyType::EcdsaSecp256k1 => {
+            let key = k256::ecdsa::VerifyingKey::from_sec1_bytes(&pubkey)
+                .map_err(|_| Status::invalid_argument("invalid secp256k1 public key encoding"))?;
+            Ok(AuthPublicKey::EcdsaSecp256k1(key))
+        }
+        ProtoKeyType::Rsa => {
+            use rsa::pkcs8::DecodePublicKey as _;
+
+            let key = rsa::RsaPublicKey::from_public_key_der(&pubkey)
+                .map_err(|_| Status::invalid_argument("invalid RSA public key encoding"))?;
+            Ok(AuthPublicKey::Rsa(key))
+        }
+    }
+}
+
+fn auth_error_status(value: &user_agent::auth::Error) -> Status {
+    use user_agent::auth::Error;
+
+    match value {
+        Error::UnexpectedMessagePayload | Error::InvalidClientPubkeyLength => {
+            Status::invalid_argument(value.to_string())
+        }
+        Error::InvalidAuthPubkeyEncoding => {
+            Status::invalid_argument("Failed to convert pubkey to VerifyingKey")
+        }
+        Error::PublicKeyNotRegistered | Error::InvalidChallengeSolution => {
+            Status::unauthenticated(value.to_string())
+        }
+        Error::InvalidBootstrapToken => Status::invalid_argument("Invalid bootstrap token"),
+        Error::Transport => Status::internal("Transport error"),
+        Error::BootstrapperActorUnreachable => {
+            Status::internal("Bootstrap token consumption failed")
+        }
+        Error::DatabasePoolUnavailable => Status::internal("Database pool error"),
+        Error::DatabaseOperationFailed => Status::internal("Database error"),
+    }
+}

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

@@ -1,137 +1,21 @@
 #![forbid(unsafe_code)]
-use arbiter_proto::{
+#![deny(
-    proto::{
+    clippy::unwrap_used,
-        client::{ClientRequest, ClientResponse},
+    clippy::expect_used,
-        user_agent::{UserAgentRequest, UserAgentResponse},
+    clippy::panic
-    },
+)]
-    transport::{IdentityRecvConverter, SendConverter, grpc},
-};
-use async_trait::async_trait;
-use tokio_stream::wrappers::ReceiverStream;
 
-use tokio::sync::mpsc;
+use crate::context::ServerContext;
-use tonic::{Request, Response, Status};
-use tracing::info;
-
-use crate::{
-    actors::{
-        client::{self, ClientConnection as ClientConnectionProps, ClientError, connect_client},
-        user_agent::{self, TransportResponseError, UserAgentConnection, connect_user_agent},
-    },
-    context::ServerContext,
-};
 
 pub mod actors;
 pub mod context;
 pub mod db;
 pub mod evm;
+pub mod grpc;
+pub mod safe_cell;
 
 const DEFAULT_CHANNEL_SIZE: usize = 1000;
 
-struct UserAgentGrpcSender;
-
-impl SendConverter for UserAgentGrpcSender {
-    type Input = Result<UserAgentResponse, TransportResponseError>;
-    type Output = Result<UserAgentResponse, Status>;
-
-    fn convert(&self, item: Self::Input) -> Self::Output {
-        match item {
-            Ok(message) => Ok(message),
-            Err(err) => Err(user_agent_error_status(err)),
-        }
-    }
-}
-
-struct ClientGrpcSender;
-
-impl SendConverter for ClientGrpcSender {
-    type Input = Result<ClientResponse, ClientError>;
-    type Output = Result<ClientResponse, Status>;
-
-    fn convert(&self, item: Self::Input) -> Self::Output {
-        match item {
-            Ok(message) => Ok(message),
-            Err(err) => Err(client_error_status(err)),
-        }
-    }
-}
-
-fn client_error_status(value: ClientError) -> Status {
-    match value {
-        ClientError::MissingRequestPayload | ClientError::UnexpectedRequestPayload => {
-            Status::invalid_argument("Expected message with payload")
-        }
-        ClientError::StateTransitionFailed => Status::internal("State machine error"),
-        ClientError::Auth(ref err) => client_auth_error_status(err),
-        ClientError::ConnectionRegistrationFailed => {
-            Status::internal("Connection registration failed")
-        }
-    }
-}
-
-fn client_auth_error_status(value: &client::auth::Error) -> Status {
-    use client::auth::Error;
-    match value {
-        Error::UnexpectedMessagePayload | Error::InvalidClientPubkeyLength => {
-            Status::invalid_argument(value.to_string())
-        }
-        Error::InvalidAuthPubkeyEncoding => {
-            Status::invalid_argument("Failed to convert pubkey to VerifyingKey")
-        }
-        Error::InvalidChallengeSolution => Status::unauthenticated(value.to_string()),
-        Error::NotRegistered => Status::permission_denied(value.to_string()),
-        Error::Transport => Status::internal("Transport error"),
-        Error::DatabasePoolUnavailable => Status::internal("Database pool error"),
-        Error::DatabaseOperationFailed => Status::internal("Database error"),
-        Error::InternalError => Status::internal("Internal error"),
-    }
-}
-
-fn user_agent_error_status(value: TransportResponseError) -> Status {
-    match value {
-        TransportResponseError::MissingRequestPayload
-        | TransportResponseError::UnexpectedRequestPayload => {
-            Status::invalid_argument("Expected message with payload")
-        }
-        TransportResponseError::InvalidStateForUnsealEncryptedKey => {
-            Status::failed_precondition("Invalid state for unseal encrypted key")
-        }
-        TransportResponseError::InvalidClientPubkeyLength => {
-            Status::invalid_argument("client_pubkey must be 32 bytes")
-        }
-        TransportResponseError::StateTransitionFailed => Status::internal("State machine error"),
-        TransportResponseError::KeyHolderActorUnreachable => {
-            Status::internal("Vault is not available")
-        }
-        TransportResponseError::Auth(ref err) => auth_error_status(err),
-        TransportResponseError::ConnectionRegistrationFailed => {
-            Status::internal("Failed registering connection")
-        }
-    }
-}
-
-fn auth_error_status(value: &user_agent::auth::Error) -> Status {
-    use user_agent::auth::Error;
-    match value {
-        Error::UnexpectedMessagePayload | Error::InvalidClientPubkeyLength => {
-            Status::invalid_argument(value.to_string())
-        }
-        Error::InvalidAuthPubkeyEncoding => {
-            Status::invalid_argument("Failed to convert pubkey to VerifyingKey")
-        }
-        Error::PublicKeyNotRegistered | Error::InvalidChallengeSolution => {
-            Status::unauthenticated(value.to_string())
-        }
-        Error::InvalidBootstrapToken => Status::invalid_argument("Invalid bootstrap token"),
-        Error::Transport => Status::internal("Transport error"),
-        Error::BootstrapperActorUnreachable => {
-            Status::internal("Bootstrap token consumption failed")
-        }
-        Error::DatabasePoolUnavailable => Status::internal("Database pool error"),
-        Error::DatabaseOperationFailed => Status::internal("Database error"),
-    }
-}
-
 pub struct Server {
     context: ServerContext,
 }
@@ -142,60 +26,3 @@ impl Server {
     }
 }
 
-#[async_trait]
-impl arbiter_proto::proto::arbiter_service_server::ArbiterService for Server {
-    type UserAgentStream = ReceiverStream<Result<UserAgentResponse, Status>>;
-    type ClientStream = ReceiverStream<Result<ClientResponse, Status>>;
-
-    #[tracing::instrument(level = "debug", skip(self))]
-    async fn client(
-        &self,
-        request: Request<tonic::Streaming<ClientRequest>>,
-    ) -> Result<Response<Self::ClientStream>, Status> {
-        let req_stream = request.into_inner();
-        let (tx, rx) = mpsc::channel(DEFAULT_CHANNEL_SIZE);
-
-        let transport = grpc::GrpcAdapter::new(
-            tx,
-            req_stream,
-            IdentityRecvConverter::<ClientRequest>::new(),
-            ClientGrpcSender,
-        );
-        let props = ClientConnectionProps::new(
-            self.context.db.clone(),
-            Box::new(transport),
-            self.context.actors.clone(),
-        );
-        tokio::spawn(connect_client(props));
-
-        info!(event = "connection established", "grpc.client");
-
-        Ok(Response::new(ReceiverStream::new(rx)))
-    }
-
-    #[tracing::instrument(level = "debug", skip(self))]
-    async fn user_agent(
-        &self,
-        request: Request<tonic::Streaming<UserAgentRequest>>,
-    ) -> Result<Response<Self::UserAgentStream>, Status> {
-        let req_stream = request.into_inner();
-        let (tx, rx) = mpsc::channel(DEFAULT_CHANNEL_SIZE);
-
-        let transport = grpc::GrpcAdapter::new(
-            tx,
-            req_stream,
-            IdentityRecvConverter::<UserAgentRequest>::new(),
-            UserAgentGrpcSender,
-        );
-        let props = UserAgentConnection::new(
-            self.context.db.clone(),
-            self.context.actors.clone(),
-            Box::new(transport),
-        );
-        tokio::spawn(connect_user_agent(props));
-
-        info!(event = "connection established", "grpc.user_agent");
-
-        Ok(Response::new(ReceiverStream::new(rx)))
-    }
-}

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

@@ -3,6 +3,7 @@ use std::net::SocketAddr;
 use arbiter_proto::{proto::arbiter_service_server::ArbiterServiceServer, url::ArbiterUrl};
 use arbiter_server::{Server, actors::bootstrap::GetToken, context::ServerContext, db};
 use miette::miette;
+use rustls::crypto::aws_lc_rs;
 use tonic::transport::{Identity, ServerTlsConfig};
 use tracing::info;
 
@@ -10,6 +11,8 @@ const PORT: u16 = 50051;
 
 #[tokio::main]
 async fn main() -> miette::Result<()> {
+    aws_lc_rs::default_provider().install_default().unwrap();
+
     tracing_subscriber::fmt()
         .with_env_filter(
             tracing_subscriber::EnvFilter::try_from_default_env()

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

@@ -0,0 +1,111 @@
+use std::ops::{Deref, DerefMut};
+use std::{any::type_name, fmt};
+
+use memsafe::MemSafe;
+
+pub trait SafeCellHandle<T> {
+    type CellRead<'a>: Deref<Target = T>
+    where
+        Self: 'a,
+        T: 'a;
+    type CellWrite<'a>: Deref<Target = T> + DerefMut<Target = T>
+    where
+        Self: 'a,
+        T: 'a;
+
+    fn new(value: T) -> Self
+    where
+        Self: Sized;
+
+    fn read(&mut self) -> Self::CellRead<'_>;
+    fn write(&mut self) -> Self::CellWrite<'_>;
+
+    fn new_inline<F>(f: F) -> Self
+    where
+        Self: Sized,
+        T: Default,
+        F: for<'a> FnOnce(&'a mut T),
+    {
+        let mut cell = Self::new(T::default());
+        {
+            let mut handle = cell.write();
+            f(handle.deref_mut());
+        }
+        cell
+    }
+
+    #[inline(always)]
+    fn read_inline<F, R>(&mut self, f: F) -> R
+    where
+        F: FnOnce(&T) -> R,
+    {
+        f(&*self.read())
+    }
+
+    #[inline(always)]
+    fn write_inline<F, R>(&mut self, f: F) -> R
+    where
+        F: FnOnce(&mut T) -> R,
+    {
+        f(&mut *self.write())
+    }
+}
+
+pub struct MemSafeCell<T>(MemSafe<T>);
+
+impl<T> fmt::Debug for MemSafeCell<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("MemSafeCell")
+            .field("inner", &format_args!("<protected {}>", type_name::<T>()))
+            .finish()
+    }
+}
+
+impl<T> SafeCellHandle<T> for MemSafeCell<T> {
+    type CellRead<'a>
+        = memsafe::MemSafeRead<'a, T>
+    where
+        Self: 'a,
+        T: 'a;
+    type CellWrite<'a>
+        = memsafe::MemSafeWrite<'a, T>
+    where
+        Self: 'a,
+        T: 'a;
+
+    fn new(value: T) -> Self {
+        match MemSafe::new(value) {
+            Ok(inner) => Self(inner),
+            Err(err) => {
+                // If protected memory cannot be allocated, process integrity is compromised.
+                abort_memory_breach("safe cell allocation", &err)
+            }
+        }
+    }
+
+    #[inline(always)]
+    fn read(&mut self) -> Self::CellRead<'_> {
+        match self.0.read() {
+            Ok(inner) => inner,
+            Err(err) => abort_memory_breach("safe cell read", &err),
+        }
+    }
+
+    #[inline(always)]
+    fn write(&mut self) -> Self::CellWrite<'_> {
+        match self.0.write() {
+            Ok(inner) => inner,
+            Err(err) => {
+                // If protected memory becomes unwritable here, treat it as a fatal memory breach.
+                abort_memory_breach("safe cell write", &err)
+            }
+        }
+    }
+}
+
+fn abort_memory_breach(action: &str, err: &memsafe::error::MemoryError) -> ! {
+    eprintln!("fatal {action}: {err}");
+    std::process::abort();
+}
+
+pub type SafeCell<T> = MemSafeCell<T>;

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

@@ -1,20 +1,7 @@
-use alloy::{
-    consensus::TxEip1559,
-    primitives::{Address, Bytes, TxKind, U256},
-    rlp::Encodable,
-};
-use arbiter_proto::proto::{
-    client::{
-        AuthChallengeRequest, AuthChallengeSolution, ClientRequest,
-        client_request::Payload as ClientRequestPayload,
-        client_response::Payload as ClientResponsePayload,
-    },
-    evm::EvmSignTransactionRequest,
-};
 use arbiter_proto::transport::Bi;
 use arbiter_server::actors::GlobalActors;
 use arbiter_server::{
-    actors::client::{ClientConnection, connect_client},
+    actors::client::{ClientConnection, Request, Response, connect_client},
     db::{self, schema},
 };
 use diesel::{ExpressionMethods as _, insert_into};
@@ -37,12 +24,8 @@ pub async fn test_unregistered_pubkey_rejected() {
     let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
 
     test_transport
-        .send(ClientRequest {
+        .send(Request::AuthChallengeRequest {
-            payload: Some(ClientRequestPayload::AuthChallengeRequest(
+            pubkey: pubkey_bytes,
-                AuthChallengeRequest {
-                    pubkey: pubkey_bytes,
-                },
-            )),
         })
         .await
         .unwrap();
@@ -76,12 +59,8 @@ pub async fn test_challenge_auth() {
 
     // Send challenge request
     test_transport
-        .send(ClientRequest {
+        .send(Request::AuthChallengeRequest {
-            payload: Some(ClientRequestPayload::AuthChallengeRequest(
+            pubkey: pubkey_bytes,
-                AuthChallengeRequest {
-                    pubkey: pubkey_bytes,
-                },
-            )),
         })
         .await
         .unwrap();
@@ -92,24 +71,20 @@ pub async fn test_challenge_auth() {
         .await
         .expect("should receive challenge");
     let challenge = match response {
-        Ok(resp) => match resp.payload {
+        Ok(resp) => match resp {
-            Some(ClientResponsePayload::AuthChallenge(c)) => c,
+            Response::AuthChallenge { pubkey, nonce } => (pubkey, nonce),
             other => panic!("Expected AuthChallenge, got {other:?}"),
         },
         Err(err) => panic!("Expected Ok response, got Err({err:?})"),
     };
 
     // Sign the challenge and send solution
-    let formatted_challenge = arbiter_proto::format_challenge(challenge.nonce, &challenge.pubkey);
+    let formatted_challenge = arbiter_proto::format_challenge(challenge.1, &challenge.0);
     let signature = new_key.sign(&formatted_challenge);
 
     test_transport
-        .send(ClientRequest {
+        .send(Request::AuthChallengeSolution {
-            payload: Some(ClientRequestPayload::AuthChallengeSolution(
+            signature: signature.to_bytes().to_vec(),
-                AuthChallengeSolution {
-                    signature: signature.to_bytes().to_vec(),
-                },
-            )),
         })
         .await
         .unwrap();
@@ -117,106 +92,3 @@ pub async fn test_challenge_auth() {
     // Auth completes, session spawned
     task.await.unwrap();
 }
-
-#[tokio::test]
-#[test_log::test]
-pub async fn test_evm_sign_request_payload_is_handled() {
-    let db = db::create_test_pool().await;
-
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
-
-    {
-        let mut conn = db.get().await.unwrap();
-        insert_into(schema::program_client::table)
-            .values(schema::program_client::public_key.eq(pubkey_bytes.clone()))
-            .execute(&mut conn)
-            .await
-            .unwrap();
-    }
-
-    let (server_transport, mut test_transport) = ChannelTransport::new();
-    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
-
-    let props = ClientConnection::new(db.clone(), Box::new(server_transport), actors);
-    let task = tokio::spawn(connect_client(props));
-
-    test_transport
-        .send(ClientRequest {
-            payload: Some(ClientRequestPayload::AuthChallengeRequest(
-                AuthChallengeRequest {
-                    pubkey: pubkey_bytes,
-                },
-            )),
-        })
-        .await
-        .unwrap();
-
-    let response = test_transport
-        .recv()
-        .await
-        .expect("should receive challenge");
-    let challenge = match response {
-        Ok(resp) => match resp.payload {
-            Some(ClientResponsePayload::AuthChallenge(c)) => c,
-            other => panic!("Expected AuthChallenge, got {other:?}"),
-        },
-        Err(err) => panic!("Expected Ok response, got Err({err:?})"),
-    };
-
-    let formatted_challenge = arbiter_proto::format_challenge(challenge.nonce, &challenge.pubkey);
-    let signature = new_key.sign(&formatted_challenge);
-
-    test_transport
-        .send(ClientRequest {
-            payload: Some(ClientRequestPayload::AuthChallengeSolution(
-                AuthChallengeSolution {
-                    signature: signature.to_bytes().to_vec(),
-                },
-            )),
-        })
-        .await
-        .unwrap();
-
-    task.await.unwrap();
-
-    let tx = TxEip1559 {
-        chain_id: 1,
-        nonce: 0,
-        gas_limit: 21_000,
-        max_fee_per_gas: 1,
-        max_priority_fee_per_gas: 1,
-        to: TxKind::Call(Address::from_slice(&[0x11; 20])),
-        value: U256::ZERO,
-        input: Bytes::new(),
-        access_list: Default::default(),
-    };
-
-    let mut rlp_transaction = Vec::new();
-    tx.encode(&mut rlp_transaction);
-
-    test_transport
-        .send(ClientRequest {
-            payload: Some(ClientRequestPayload::EvmSignTransaction(
-                EvmSignTransactionRequest {
-                    wallet_address: [0x22; 20].to_vec(),
-                    rlp_transaction,
-                },
-            )),
-        })
-        .await
-        .unwrap();
-
-    let response = test_transport
-        .recv()
-        .await
-        .expect("should receive sign response");
-
-    match response {
-        Ok(resp) => match resp.payload {
-            Some(ClientResponsePayload::EvmSignTransaction(_)) => {}
-            other => panic!("Expected EvmSignTransaction response, got {other:?}"),
-        },
-        Err(err) => panic!("Expected Ok response, got Err({err:?})"),
-    }
-}

server/crates/arbiter-server/tests/common/mod.rs

@@ -1,19 +1,18 @@
 use arbiter_proto::transport::{Bi, Error};
 use arbiter_server::{
     actors::keyholder::KeyHolder,
-    db::{self, schema},
+    db::{self, schema}, safe_cell::{SafeCell, SafeCellHandle as _},
 };
 use async_trait::async_trait;
 use diesel::QueryDsl;
 use diesel_async::RunQueryDsl;
-use memsafe::MemSafe;
 use tokio::sync::mpsc;
 
 #[allow(dead_code)]
 pub async fn bootstrapped_keyholder(db: &db::DatabasePool) -> KeyHolder {
     let mut actor = KeyHolder::new(db.clone()).await.unwrap();
     actor
-        .bootstrap(MemSafe::new(b"test-seal-key".to_vec()).unwrap())
+        .bootstrap(SafeCell::new(b"test-seal-key".to_vec()))
         .await
         .unwrap();
     actor

server/crates/arbiter-server/tests/keyholder/concurrency.rs

@@ -3,11 +3,11 @@ use std::collections::{HashMap, HashSet};
 use arbiter_server::{
     actors::keyholder::{CreateNew, Error, KeyHolder},
     db::{self, models, schema},
+    safe_cell::{SafeCell, SafeCellHandle as _},
 };
 use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper, dsl::sql_query};
 use diesel_async::RunQueryDsl;
 use kameo::actor::{ActorRef, Spawn as _};
-use memsafe::MemSafe;
 use tokio::task::JoinSet;
 
 use crate::common;
@@ -24,7 +24,7 @@ async fn write_concurrently(
             let plaintext = format!("{prefix}-{i}").into_bytes();
             let id = actor
                 .ask(CreateNew {
-                    plaintext: MemSafe::new(plaintext.clone()).unwrap(),
+                    plaintext: SafeCell::new(plaintext.clone()),
                 })
                 .await
                 .unwrap();
@@ -118,7 +118,7 @@ async fn insert_failure_does_not_create_partial_row() {
     drop(conn);
 
     let err = actor
-        .create_new(MemSafe::new(b"should fail".to_vec()).unwrap())
+        .create_new(SafeCell::new(b"should fail".to_vec()))
         .await
         .unwrap_err();
     assert!(matches!(err, Error::DatabaseTransaction(_)));
@@ -162,12 +162,12 @@ async fn decrypt_roundtrip_after_high_concurrency() {
 
     let mut decryptor = KeyHolder::new(db.clone()).await.unwrap();
     decryptor
-        .try_unseal(MemSafe::new(b"test-seal-key".to_vec()).unwrap())
+        .try_unseal(SafeCell::new(b"test-seal-key".to_vec()))
         .await
         .unwrap();
 
     for (id, plaintext) in expected {
         let mut decrypted = decryptor.decrypt(id).await.unwrap();
-        assert_eq!(*decrypted.read().unwrap(), plaintext);
+        assert_eq!(*decrypted.read(), plaintext);
     }
 }

server/crates/arbiter-server/tests/keyholder/lifecycle.rs

@@ -1,10 +1,10 @@
 use arbiter_server::{
     actors::keyholder::{Error, KeyHolder},
     db::{self, models, schema},
+    safe_cell::{SafeCell, SafeCellHandle as _},
 };
 use diesel::{QueryDsl, SelectableHelper};
 use diesel_async::RunQueryDsl;
-use memsafe::MemSafe;
 
 use crate::common;
 
@@ -14,7 +14,7 @@ async fn test_bootstrap() {
     let db = db::create_test_pool().await;
     let mut actor = KeyHolder::new(db.clone()).await.unwrap();
 
-    let seal_key = MemSafe::new(b"test-seal-key".to_vec()).unwrap();
+    let seal_key = SafeCell::new(b"test-seal-key".to_vec());
     actor.bootstrap(seal_key).await.unwrap();
 
     let mut conn = db.get().await.unwrap();
@@ -43,7 +43,7 @@ async fn test_bootstrap_rejects_double() {
     let db = db::create_test_pool().await;
     let mut actor = common::bootstrapped_keyholder(&db).await;
 
-    let seal_key2 = MemSafe::new(b"test-seal-key".to_vec()).unwrap();
+    let seal_key2 = SafeCell::new(b"test-seal-key".to_vec());
     let err = actor.bootstrap(seal_key2).await.unwrap_err();
     assert!(matches!(err, Error::AlreadyBootstrapped));
 }
@@ -55,7 +55,7 @@ async fn test_create_new_before_bootstrap_fails() {
     let mut actor = KeyHolder::new(db).await.unwrap();
 
     let err = actor
-        .create_new(MemSafe::new(b"data".to_vec()).unwrap())
+        .create_new(SafeCell::new(b"data".to_vec()))
         .await
         .unwrap_err();
     assert!(matches!(err, Error::NotBootstrapped));
@@ -91,17 +91,17 @@ async fn test_unseal_correct_password() {
 
     let plaintext = b"survive a restart";
     let aead_id = actor
-        .create_new(MemSafe::new(plaintext.to_vec()).unwrap())
+        .create_new(SafeCell::new(plaintext.to_vec()))
         .await
         .unwrap();
     drop(actor);
 
     let mut actor = KeyHolder::new(db.clone()).await.unwrap();
-    let seal_key = MemSafe::new(b"test-seal-key".to_vec()).unwrap();
+    let seal_key = SafeCell::new(b"test-seal-key".to_vec());
     actor.try_unseal(seal_key).await.unwrap();
 
     let mut decrypted = actor.decrypt(aead_id).await.unwrap();
-    assert_eq!(*decrypted.read().unwrap(), plaintext);
+    assert_eq!(*decrypted.read(), plaintext);
 }
 
 #[tokio::test]
@@ -112,20 +112,20 @@ async fn test_unseal_wrong_then_correct_password() {
 
     let plaintext = b"important data";
     let aead_id = actor
-        .create_new(MemSafe::new(plaintext.to_vec()).unwrap())
+        .create_new(SafeCell::new(plaintext.to_vec()))
         .await
         .unwrap();
     drop(actor);
 
     let mut actor = KeyHolder::new(db.clone()).await.unwrap();
 
-    let bad_key = MemSafe::new(b"wrong-password".to_vec()).unwrap();
+    let bad_key = SafeCell::new(b"wrong-password".to_vec());
     let err = actor.try_unseal(bad_key).await.unwrap_err();
     assert!(matches!(err, Error::InvalidKey));
 
-    let good_key = MemSafe::new(b"test-seal-key".to_vec()).unwrap();
+    let good_key = SafeCell::new(b"test-seal-key".to_vec());
     actor.try_unseal(good_key).await.unwrap();
 
     let mut decrypted = actor.decrypt(aead_id).await.unwrap();
-    assert_eq!(*decrypted.read().unwrap(), plaintext);
+    assert_eq!(*decrypted.read(), plaintext);
 }

server/crates/arbiter-server/tests/keyholder/storage.rs

@@ -3,10 +3,10 @@ use std::collections::HashSet;
 use arbiter_server::{
     actors::keyholder::{Error, encryption::v1},
     db::{self, models, schema},
+    safe_cell::{SafeCell, SafeCellHandle as _},
 };
 use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper, dsl::update};
 use diesel_async::RunQueryDsl;
-use memsafe::MemSafe;
 
 use crate::common;
 
@@ -18,12 +18,12 @@ async fn test_create_decrypt_roundtrip() {
 
     let plaintext = b"hello arbiter";
     let aead_id = actor
-        .create_new(MemSafe::new(plaintext.to_vec()).unwrap())
+        .create_new(SafeCell::new(plaintext.to_vec()))
         .await
         .unwrap();
 
     let mut decrypted = actor.decrypt(aead_id).await.unwrap();
-    assert_eq!(*decrypted.read().unwrap(), plaintext);
+    assert_eq!(*decrypted.read(), plaintext);
 }
 
 #[tokio::test]
@@ -44,11 +44,11 @@ async fn test_ciphertext_differs_across_entries() {
 
     let plaintext = b"same content";
     let id1 = actor
-        .create_new(MemSafe::new(plaintext.to_vec()).unwrap())
+        .create_new(SafeCell::new(plaintext.to_vec()))
         .await
         .unwrap();
     let id2 = actor
-        .create_new(MemSafe::new(plaintext.to_vec()).unwrap())
+        .create_new(SafeCell::new(plaintext.to_vec()))
         .await
         .unwrap();
 
@@ -70,8 +70,8 @@ async fn test_ciphertext_differs_across_entries() {
 
     let mut d1 = actor.decrypt(id1).await.unwrap();
     let mut d2 = actor.decrypt(id2).await.unwrap();
-    assert_eq!(*d1.read().unwrap(), plaintext);
+    assert_eq!(*d1.read(), plaintext);
-    assert_eq!(*d2.read().unwrap(), plaintext);
+    assert_eq!(*d2.read(), plaintext);
 }
 
 #[tokio::test]
@@ -83,7 +83,7 @@ async fn test_nonce_never_reused() {
     let n = 5;
     for i in 0..n {
         actor
-            .create_new(MemSafe::new(format!("secret {i}").into_bytes()).unwrap())
+            .create_new(SafeCell::new(format!("secret {i}").into_bytes()))
             .await
             .unwrap();
     }
@@ -137,7 +137,7 @@ async fn broken_db_nonce_format_fails_closed() {
     drop(conn);
 
     let err = actor
-        .create_new(MemSafe::new(b"must fail".to_vec()).unwrap())
+        .create_new(SafeCell::new(b"must fail".to_vec()))
         .await
         .unwrap_err();
     assert!(matches!(err, Error::BrokenDatabase));
@@ -145,7 +145,7 @@ async fn broken_db_nonce_format_fails_closed() {
     let db = db::create_test_pool().await;
     let mut actor = common::bootstrapped_keyholder(&db).await;
     let id = actor
-        .create_new(MemSafe::new(b"decrypt target".to_vec()).unwrap())
+        .create_new(SafeCell::new(b"decrypt target".to_vec()))
         .await
         .unwrap();
     let mut conn = db.get().await.unwrap();

server/crates/arbiter-server/tests/user_agent.rs

@@ -2,7 +2,5 @@ mod common;
 
 #[path = "user_agent/auth.rs"]
 mod auth;
-#[path = "user_agent/sdk_client.rs"]
-mod sdk_client;
 #[path = "user_agent/unseal.rs"]
 mod unseal;

server/crates/arbiter-server/tests/user_agent/auth.rs

@@ -1,14 +1,9 @@
-use arbiter_proto::proto::user_agent::{
-    AuthChallengeRequest, AuthChallengeSolution, KeyType as ProtoKeyType, UserAgentRequest,
-    user_agent_request::Payload as UserAgentRequestPayload,
-    user_agent_response::Payload as UserAgentResponsePayload,
-};
 use arbiter_proto::transport::Bi;
 use arbiter_server::{
     actors::{
         GlobalActors,
         bootstrap::GetToken,
-        user_agent::{UserAgentConnection, connect_user_agent},
+        user_agent::{AuthPublicKey, Request, Response, UserAgentConnection, connect_user_agent},
     },
     db::{self, schema},
 };
@@ -30,17 +25,10 @@ pub async fn test_bootstrap_token_auth() {
     let task = tokio::spawn(connect_user_agent(props));
 
     let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
-
     test_transport
-        .send(UserAgentRequest {
+        .send(Request::AuthChallengeRequest {
-            payload: Some(UserAgentRequestPayload::AuthChallengeRequest(
+            pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
-                AuthChallengeRequest {
+            bootstrap_token: Some(token),
-                    pubkey: pubkey_bytes,
-                    bootstrap_token: Some(token),
-                    key_type: ProtoKeyType::Ed25519.into(),
-                },
-            )),
         })
         .await
         .unwrap();
@@ -67,17 +55,10 @@ pub async fn test_bootstrap_invalid_token_auth() {
     let task = tokio::spawn(connect_user_agent(props));
 
     let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
-
     test_transport
-        .send(UserAgentRequest {
+        .send(Request::AuthChallengeRequest {
-            payload: Some(UserAgentRequestPayload::AuthChallengeRequest(
+            pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
-                AuthChallengeRequest {
+            bootstrap_token: Some("invalid_token".to_string()),
-                    pubkey: pubkey_bytes,
-                    bootstrap_token: Some("invalid_token".to_string()),
-                    key_type: ProtoKeyType::Ed25519.into(),
-                },
-            )),
         })
         .await
         .unwrap();
@@ -123,14 +104,9 @@ pub async fn test_challenge_auth() {
 
     // Send challenge request
     test_transport
-        .send(UserAgentRequest {
+        .send(Request::AuthChallengeRequest {
-            payload: Some(UserAgentRequestPayload::AuthChallengeRequest(
+            pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
-                AuthChallengeRequest {
+            bootstrap_token: None,
-                    pubkey: pubkey_bytes,
-                    bootstrap_token: None,
-                    key_type: ProtoKeyType::Ed25519.into(),
-                },
-            )),
         })
         .await
         .unwrap();
@@ -141,24 +117,19 @@ pub async fn test_challenge_auth() {
         .await
         .expect("should receive challenge");
     let challenge = match response {
-        Ok(resp) => match resp.payload {
+        Ok(resp) => match resp {
-            Some(UserAgentResponsePayload::AuthChallenge(c)) => c,
+            Response::AuthChallenge { nonce } => nonce,
             other => panic!("Expected AuthChallenge, got {other:?}"),
         },
         Err(err) => panic!("Expected Ok response, got Err({err:?})"),
     };
 
-    // Sign the challenge and send solution
+    let formatted_challenge = arbiter_proto::format_challenge(challenge, &pubkey_bytes);
-    let formatted_challenge = arbiter_proto::format_challenge(challenge.nonce, &challenge.pubkey);
     let signature = new_key.sign(&formatted_challenge);
 
     test_transport
-        .send(UserAgentRequest {
+        .send(Request::AuthChallengeSolution {
-            payload: Some(UserAgentRequestPayload::AuthChallengeSolution(
+            signature: signature.to_bytes().to_vec(),
-                AuthChallengeSolution {
-                    signature: signature.to_bytes().to_vec(),
-                },
-            )),
         })
         .await
         .unwrap();

server/crates/arbiter-server/tests/user_agent/sdk_client.rs

@@ -1,270 +0,0 @@
-use arbiter_proto::proto::user_agent::{
-    SdkClientApproveRequest, SdkClientError as ProtoSdkClientError, SdkClientRevokeRequest,
-    UserAgentRequest, sdk_client_approve_response, sdk_client_list_response,
-    sdk_client_revoke_response, user_agent_request::Payload as UserAgentRequestPayload,
-    user_agent_response::Payload as UserAgentResponsePayload,
-};
-use arbiter_server::{
-    actors::{GlobalActors, user_agent::session::UserAgentSession},
-    db,
-};
-
-/// Shared helper: create a session and register a client pubkey via sdk_client_approve.
-async fn make_session(db: &db::DatabasePool) -> UserAgentSession {
-    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
-    UserAgentSession::new_test(db.clone(), actors)
-}
-
-#[tokio::test]
-#[test_log::test]
-async fn test_sdk_client_approve_registers_client() {
-    let db = db::create_test_pool().await;
-    let mut session = make_session(&db).await;
-
-    let pubkey = [0x42u8; 32];
-
-    let response = session
-        .process_transport_inbound(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::SdkClientApprove(
-                SdkClientApproveRequest {
-                    pubkey: pubkey.to_vec(),
-                },
-            )),
-        })
-        .await
-        .expect("handler should succeed");
-
-    let entry = match response.payload.unwrap() {
-        UserAgentResponsePayload::SdkClientApprove(resp) => match resp.result.unwrap() {
-            sdk_client_approve_response::Result::Client(e) => e,
-            sdk_client_approve_response::Result::Error(e) => {
-                panic!("Expected Client, got error {:?}", e)
-            }
-        },
-        other => panic!("Expected SdkClientApprove, got {other:?}"),
-    };
-
-    assert_eq!(entry.pubkey, pubkey.to_vec());
-    assert!(entry.id > 0);
-}
-
-#[tokio::test]
-#[test_log::test]
-async fn test_sdk_client_approve_duplicate_returns_already_exists() {
-    let db = db::create_test_pool().await;
-    let mut session = make_session(&db).await;
-
-    let pubkey = [0x11u8; 32];
-    let req = UserAgentRequest {
-        payload: Some(UserAgentRequestPayload::SdkClientApprove(
-            SdkClientApproveRequest {
-                pubkey: pubkey.to_vec(),
-            },
-        )),
-    };
-
-    session
-        .process_transport_inbound(req.clone())
-        .await
-        .unwrap();
-
-    let response = session
-        .process_transport_inbound(req)
-        .await
-        .expect("second insert should not panic");
-
-    match response.payload.unwrap() {
-        UserAgentResponsePayload::SdkClientApprove(resp) => match resp.result.unwrap() {
-            sdk_client_approve_response::Result::Error(code) => {
-                assert_eq!(code, ProtoSdkClientError::AlreadyExists as i32);
-            }
-            sdk_client_approve_response::Result::Client(_) => {
-                panic!("Expected AlreadyExists error for duplicate pubkey")
-            }
-        },
-        other => panic!("Expected SdkClientApprove, got {other:?}"),
-    }
-}
-
-#[tokio::test]
-#[test_log::test]
-async fn test_sdk_client_list_shows_registered_clients() {
-    let db = db::create_test_pool().await;
-    let mut session = make_session(&db).await;
-
-    let pubkey_a = [0x0Au8; 32];
-    let pubkey_b = [0x0Bu8; 32];
-
-    for pubkey in [pubkey_a, pubkey_b] {
-        session
-            .process_transport_inbound(UserAgentRequest {
-                payload: Some(UserAgentRequestPayload::SdkClientApprove(
-                    SdkClientApproveRequest {
-                        pubkey: pubkey.to_vec(),
-                    },
-                )),
-            })
-            .await
-            .unwrap();
-    }
-
-    let response = session
-        .process_transport_inbound(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::SdkClientList(())),
-        })
-        .await
-        .expect("list should succeed");
-
-    let clients = match response.payload.unwrap() {
-        UserAgentResponsePayload::SdkClientList(resp) => match resp.result.unwrap() {
-            sdk_client_list_response::Result::Clients(list) => list.clients,
-            sdk_client_list_response::Result::Error(e) => {
-                panic!("Expected Clients, got error {:?}", e)
-            }
-        },
-        other => panic!("Expected SdkClientList, got {other:?}"),
-    };
-
-    assert_eq!(clients.len(), 2);
-    let pubkeys: Vec<Vec<u8>> = clients.into_iter().map(|e| e.pubkey).collect();
-    assert!(pubkeys.contains(&pubkey_a.to_vec()));
-    assert!(pubkeys.contains(&pubkey_b.to_vec()));
-}
-
-#[tokio::test]
-#[test_log::test]
-async fn test_sdk_client_revoke_removes_client() {
-    let db = db::create_test_pool().await;
-    let mut session = make_session(&db).await;
-
-    let pubkey = [0xBBu8; 32];
-
-    // Register a client and get its id
-    let approve_response = session
-        .process_transport_inbound(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::SdkClientApprove(
-                SdkClientApproveRequest {
-                    pubkey: pubkey.to_vec(),
-                },
-            )),
-        })
-        .await
-        .unwrap();
-
-    let client_id = match approve_response.payload.unwrap() {
-        UserAgentResponsePayload::SdkClientApprove(resp) => match resp.result.unwrap() {
-            sdk_client_approve_response::Result::Client(e) => e.id,
-            sdk_client_approve_response::Result::Error(e) => panic!("approve failed: {:?}", e),
-        },
-        other => panic!("{other:?}"),
-    };
-
-    // Revoke the client
-    let revoke_response = session
-        .process_transport_inbound(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::SdkClientRevoke(
-                SdkClientRevokeRequest { client_id },
-            )),
-        })
-        .await
-        .expect("revoke should succeed");
-
-    match revoke_response.payload.unwrap() {
-        UserAgentResponsePayload::SdkClientRevoke(resp) => match resp.result.unwrap() {
-            sdk_client_revoke_response::Result::Ok(_) => {}
-            sdk_client_revoke_response::Result::Error(e) => {
-                panic!("Expected Ok, got error {:?}", e)
-            }
-        },
-        other => panic!("Expected SdkClientRevoke, got {other:?}"),
-    }
-
-    // List should now be empty
-    let list_response = session
-        .process_transport_inbound(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::SdkClientList(())),
-        })
-        .await
-        .unwrap();
-
-    let clients = match list_response.payload.unwrap() {
-        UserAgentResponsePayload::SdkClientList(resp) => match resp.result.unwrap() {
-            sdk_client_list_response::Result::Clients(list) => list.clients,
-            sdk_client_list_response::Result::Error(e) => panic!("list error: {:?}", e),
-        },
-        other => panic!("{other:?}"),
-    };
-    assert!(clients.is_empty(), "client should be removed after revoke");
-}
-
-#[tokio::test]
-#[test_log::test]
-async fn test_sdk_client_revoke_not_found_returns_error() {
-    let db = db::create_test_pool().await;
-    let mut session = make_session(&db).await;
-
-    let response = session
-        .process_transport_inbound(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::SdkClientRevoke(
-                SdkClientRevokeRequest { client_id: 9999 },
-            )),
-        })
-        .await
-        .unwrap();
-
-    match response.payload.unwrap() {
-        UserAgentResponsePayload::SdkClientRevoke(resp) => match resp.result.unwrap() {
-            sdk_client_revoke_response::Result::Error(code) => {
-                assert_eq!(code, ProtoSdkClientError::NotFound as i32);
-            }
-            sdk_client_revoke_response::Result::Ok(_) => {
-                panic!("Expected NotFound error for missing client_id")
-            }
-        },
-        other => panic!("Expected SdkClientRevoke, got {other:?}"),
-    }
-}
-
-#[tokio::test]
-#[test_log::test]
-async fn test_sdk_client_approve_rejected_client_cannot_auth() {
-    // Verify the core flow: only pre-approved clients can authenticate
-    use arbiter_proto::proto::client::{
-        AuthChallengeRequest, ClientRequest, client_request::Payload as ClientRequestPayload,
-        client_response::Payload as ClientResponsePayload,
-    };
-    use arbiter_proto::transport::Bi as _;
-    use arbiter_server::actors::client::{ClientConnection, connect_client};
-
-    let db = db::create_test_pool().await;
-    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
-
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
-
-    let (server_transport, mut test_transport) = super::common::ChannelTransport::<_, _>::new();
-    let props = ClientConnection::new(db.clone(), Box::new(server_transport), actors.clone());
-    let task = tokio::spawn(connect_client(props));
-
-    test_transport
-        .send(ClientRequest {
-            payload: Some(ClientRequestPayload::AuthChallengeRequest(
-                AuthChallengeRequest {
-                    pubkey: pubkey_bytes.clone(),
-                },
-            )),
-        })
-        .await
-        .unwrap();
-
-    let response = test_transport.recv().await.unwrap().unwrap();
-    assert!(
-        matches!(
-            response.payload.unwrap(),
-            ClientResponsePayload::ClientConnectError(_)
-        ),
-        "unregistered client should be rejected"
-    );
-
-    task.await.unwrap();
-}

server/crates/arbiter-server/tests/user_agent/unseal.rs

@@ -1,30 +1,23 @@
-use arbiter_proto::proto::user_agent::{
-    UnsealEncryptedKey, UnsealResult, UnsealStart, UserAgentRequest,
-    user_agent_request::Payload as UserAgentRequestPayload,
-    user_agent_response::Payload as UserAgentResponsePayload,
-};
 use arbiter_server::{
     actors::{
         GlobalActors,
         keyholder::{Bootstrap, Seal},
-        user_agent::session::UserAgentSession,
+        user_agent::{Request, Response, UnsealError, session::UserAgentSession},
     },
     db,
+    safe_cell::{SafeCell, SafeCellHandle as _},
 };
 use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
-use memsafe::MemSafe;
 use x25519_dalek::{EphemeralSecret, PublicKey};
 
-async fn setup_sealed_user_agent(
+async fn setup_sealed_user_agent(seal_key: &[u8]) -> (db::DatabasePool, UserAgentSession) {
-    seal_key: &[u8],
-) -> (db::DatabasePool, UserAgentSession) {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
 
     actors
         .key_holder
         .ask(Bootstrap {
-            seal_key_raw: MemSafe::new(seal_key.to_vec()).unwrap(),
+            seal_key_raw: SafeCell::new(seal_key.to_vec()),
         })
         .await
         .unwrap();
@@ -35,29 +28,23 @@ async fn setup_sealed_user_agent(
     (db, session)
 }
 
-async fn client_dh_encrypt(
+async fn client_dh_encrypt(user_agent: &mut UserAgentSession, key_to_send: &[u8]) -> Request {
-    user_agent: &mut UserAgentSession,
-    key_to_send: &[u8],
-) -> UnsealEncryptedKey {
     let client_secret = EphemeralSecret::random();
     let client_public = PublicKey::from(&client_secret);
 
     let response = user_agent
-        .process_transport_inbound(UserAgentRequest {
+        .process_transport_inbound(Request::UnsealStart {
-            payload: Some(UserAgentRequestPayload::UnsealStart(UnsealStart {
+            client_pubkey: client_public,
-                client_pubkey: client_public.as_bytes().to_vec(),
-            })),
         })
         .await
         .unwrap();
 
-    let server_pubkey = match response.payload.unwrap() {
+    let server_pubkey = match response {
-        UserAgentResponsePayload::UnsealStartResponse(resp) => resp.server_pubkey,
+        Response::UnsealStartResponse { server_pubkey } => server_pubkey,
         other => panic!("Expected UnsealStartResponse, got {other:?}"),
     };
-    let server_public = PublicKey::from(<[u8; 32]>::try_from(server_pubkey.as_slice()).unwrap());
 
-    let shared_secret = client_secret.diffie_hellman(&server_public);
+    let shared_secret = client_secret.diffie_hellman(&server_pubkey);
     let cipher = XChaCha20Poly1305::new(shared_secret.as_bytes().into());
     let nonce = XNonce::from([0u8; 24]);
     let associated_data = b"unseal";
@@ -66,19 +53,13 @@ async fn client_dh_encrypt(
         .encrypt_in_place(&nonce, associated_data, &mut ciphertext)
         .unwrap();
 
-    UnsealEncryptedKey {
+    Request::UnsealEncryptedKey {
         nonce: nonce.to_vec(),
         ciphertext,
         associated_data: associated_data.to_vec(),
     }
 }
 
-fn unseal_key_request(req: UnsealEncryptedKey) -> UserAgentRequest {
-    UserAgentRequest {
-        payload: Some(UserAgentRequestPayload::UnsealEncryptedKey(req)),
-    }
-}
-
 #[tokio::test]
 #[test_log::test]
 pub async fn test_unseal_success() {
@@ -88,14 +69,11 @@ pub async fn test_unseal_success() {
     let encrypted_key = client_dh_encrypt(&mut user_agent, seal_key).await;
 
     let response = user_agent
-        .process_transport_inbound(unseal_key_request(encrypted_key))
+        .process_transport_inbound(encrypted_key)
         .await
         .unwrap();
 
-    assert_eq!(
+    assert!(matches!(response, Response::UnsealResult(Ok(()))));
-        response.payload.unwrap(),
-        UserAgentResponsePayload::UnsealResult(UnsealResult::Success.into()),
-    );
 }
 
 #[tokio::test]
@@ -106,14 +84,14 @@ pub async fn test_unseal_wrong_seal_key() {
     let encrypted_key = client_dh_encrypt(&mut user_agent, b"wrong-key").await;
 
     let response = user_agent
-        .process_transport_inbound(unseal_key_request(encrypted_key))
+        .process_transport_inbound(encrypted_key)
         .await
         .unwrap();
 
-    assert_eq!(
+    assert!(matches!(
-        response.payload.unwrap(),
+        response,
-        UserAgentResponsePayload::UnsealResult(UnsealResult::InvalidKey.into()),
+        Response::UnsealResult(Err(UnsealError::InvalidKey))
-    );
+    ));
 }
 
 #[tokio::test]
@@ -125,27 +103,25 @@ pub async fn test_unseal_corrupted_ciphertext() {
     let client_public = PublicKey::from(&client_secret);
 
     user_agent
-        .process_transport_inbound(UserAgentRequest {
+        .process_transport_inbound(Request::UnsealStart {
-            payload: Some(UserAgentRequestPayload::UnsealStart(UnsealStart {
+            client_pubkey: client_public,
-                client_pubkey: client_public.as_bytes().to_vec(),
-            })),
         })
         .await
         .unwrap();
 
     let response = user_agent
-        .process_transport_inbound(unseal_key_request(UnsealEncryptedKey {
+        .process_transport_inbound(Request::UnsealEncryptedKey {
             nonce: vec![0u8; 24],
             ciphertext: vec![0u8; 32],
             associated_data: vec![],
-        }))
+        })
         .await
         .unwrap();
 
-    assert_eq!(
+    assert!(matches!(
-        response.payload.unwrap(),
+        response,
-        UserAgentResponsePayload::UnsealResult(UnsealResult::InvalidKey.into()),
+        Response::UnsealResult(Err(UnsealError::InvalidKey))
-    );
+    ));
 }
 
 #[tokio::test]
@@ -158,27 +134,24 @@ pub async fn test_unseal_retry_after_invalid_key() {
         let encrypted_key = client_dh_encrypt(&mut user_agent, b"wrong-key").await;
 
         let response = user_agent
-            .process_transport_inbound(unseal_key_request(encrypted_key))
+            .process_transport_inbound(encrypted_key)
             .await
             .unwrap();
 
-        assert_eq!(
+        assert!(matches!(
-            response.payload.unwrap(),
+            response,
-            UserAgentResponsePayload::UnsealResult(UnsealResult::InvalidKey.into()),
+            Response::UnsealResult(Err(UnsealError::InvalidKey))
-        );
+        ));
     }
 
     {
         let encrypted_key = client_dh_encrypt(&mut user_agent, seal_key).await;
 
         let response = user_agent
-            .process_transport_inbound(unseal_key_request(encrypted_key))
+            .process_transport_inbound(encrypted_key)
             .await
             .unwrap();
 
-        assert_eq!(
+        assert!(matches!(response, Response::UnsealResult(Ok(()))));
-            response.payload.unwrap(),
-            UserAgentResponsePayload::UnsealResult(UnsealResult::Success.into()),
-        );
     }
 }

server/crates/arbiter-terrors-poc/Cargo.toml

@@ -1,7 +0,0 @@
-[package]
-name = "arbiter-terrors-poc"
-version = "0.1.0"
-edition = "2024"
-
-[dependencies]
-terrors = "0.3"

server/crates/arbiter-terrors-poc/src/auth.rs

@@ -1,139 +0,0 @@
-use crate::errors::{InternalError1, InternalError2, InvalidSignature, NotRegistered};
-use terrors::OneOf;
-
-use crate::errors::ProtoError;
-
-// Each sub-call's error type already implements DrainInto<ProtoError>, so we convert
-// directly to ProtoError without broaden — no turbofish needed anywhere.
-//
-// Call chain:
-//   load_config()  → OneOf<(InternalError2,)>          → ProtoError::from
-//   get_nonce()    → OneOf<(InternalError1, InternalError2)> → ProtoError::from
-//   verify_sig()   → OneOf<(InvalidSignature,)>         → ProtoError::from
-pub fn process_request(id: u32, sig: &str) -> Result<String, ProtoError> {
-    if id == 0 {
-        return Err(ProtoError::NotRegistered);
-    }
-
-    let config = load_config(id).map_err(ProtoError::from)?;
-    let nonce = crate::db::get_nonce(id).map_err(ProtoError::from)?;
-    verify_signature(nonce, sig).map_err(ProtoError::from)?;
-
-    Ok(format!("config={config} nonce={nonce} sig={sig}"))
-}
-
-// Simulates loading a config value.
-// id=97 triggers InternalError2 ("config read failed").
-fn load_config(id: u32) -> Result<String, OneOf<(InternalError2,)>> {
-    if id == 97 {
-        return Err(OneOf::new(InternalError2("config read failed".to_owned())));
-    }
-    Ok(format!("cfg-{id}"))
-}
-
-pub fn verify_signature(_nonce: u32, sig: &str) -> Result<(), OneOf<(InvalidSignature,)>> {
-    if sig != "ok" {
-        return Err(OneOf::new(InvalidSignature));
-    }
-    Ok(())
-}
-
-type AuthError = OneOf<(
-    NotRegistered,
-    InvalidSignature,
-    InternalError1,
-    InternalError2,
-)>;
-
-pub fn authenticate(id: u32, sig: &str) -> Result<u32, AuthError> {
-    if id == 0 {
-        return Err(OneOf::new(NotRegistered));
-    }
-
-    // Return type AuthError lets the compiler infer the broaden target.
-    let nonce = crate::db::get_nonce(id).map_err(OneOf::broaden)?;
-    verify_signature(nonce, sig).map_err(OneOf::broaden)?;
-
-    Ok(nonce)
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn verify_signature_ok() {
-        assert!(verify_signature(42, "ok").is_ok());
-    }
-
-    #[test]
-    fn verify_signature_bad() {
-        let err = verify_signature(42, "bad").unwrap_err();
-        assert!(err.narrow::<crate::errors::InvalidSignature, _>().is_ok());
-    }
-
-    #[test]
-    fn authenticate_success() {
-        assert_eq!(authenticate(1, "ok").unwrap(), 42);
-    }
-
-    #[test]
-    fn authenticate_not_registered() {
-        let err = authenticate(0, "ok").unwrap_err();
-        assert!(err.narrow::<crate::errors::NotRegistered, _>().is_ok());
-    }
-
-    #[test]
-    fn authenticate_invalid_signature() {
-        let err = authenticate(1, "bad").unwrap_err();
-        assert!(err.narrow::<crate::errors::InvalidSignature, _>().is_ok());
-    }
-
-    #[test]
-    fn authenticate_internal_error1() {
-        let err = authenticate(99, "ok").unwrap_err();
-        assert!(err.narrow::<crate::errors::InternalError1, _>().is_ok());
-    }
-
-    #[test]
-    fn authenticate_internal_error2() {
-        let err = authenticate(98, "ok").unwrap_err();
-        assert!(err.narrow::<crate::errors::InternalError2, _>().is_ok());
-    }
-
-    #[test]
-    fn process_request_success() {
-        let result = process_request(1, "ok").unwrap();
-        assert!(result.contains("nonce=42"));
-    }
-
-    #[test]
-    fn process_request_not_registered() {
-        let err = process_request(0, "ok").unwrap_err();
-        assert!(matches!(err, crate::errors::ProtoError::NotRegistered));
-    }
-
-    #[test]
-    fn process_request_invalid_signature() {
-        let err = process_request(1, "bad").unwrap_err();
-        assert!(matches!(err, crate::errors::ProtoError::InvalidSignature));
-    }
-
-    #[test]
-    fn process_request_internal_from_config() {
-        // id=97 → load_config returns InternalError2
-        let err = process_request(97, "ok").unwrap_err();
-        assert!(
-            matches!(err, crate::errors::ProtoError::Internal(ref msg) if msg == "config read failed")
-        );
-    }
-
-    #[test]
-    fn process_request_internal_from_db() {
-        // id=99 → get_nonce returns InternalError1
-        let err = process_request(99, "ok").unwrap_err();
-        assert!(
-            matches!(err, crate::errors::ProtoError::Internal(ref msg) if msg == "db pool unavailable")
-        );
-    }
-}

server/crates/arbiter-terrors-poc/src/db.rs

@@ -1,38 +0,0 @@
-use crate::errors::{InternalError1, InternalError2};
-use terrors::OneOf;
-
-// Simulates fetching a nonce from a database.
-// id=99 → InternalError1 (pool unavailable)
-// id=98 → InternalError2 (query timeout)
-pub fn get_nonce(id: u32) -> Result<u32, OneOf<(InternalError1, InternalError2)>> {
-    match id {
-        99 => Err(OneOf::new(InternalError1("db pool unavailable".to_owned()))),
-        98 => Err(OneOf::new(InternalError2("query timeout".to_owned()))),
-        _ => Ok(42),
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn get_nonce_returns_nonce_for_valid_id() {
-        assert_eq!(get_nonce(1).unwrap(), 42);
-    }
-
-    #[test]
-    fn get_nonce_returns_internal_error1_for_sentinel() {
-        let err = get_nonce(99).unwrap_err();
-        let internal = err.narrow::<crate::errors::InternalError1, _>().unwrap();
-        assert_eq!(internal.0, "db pool unavailable");
-    }
-
-    #[test]
-    fn get_nonce_returns_internal_error2_for_sentinel() {
-        let err = get_nonce(98).unwrap_err();
-        let e = err.narrow::<crate::errors::InternalError1, _>().unwrap_err();
-        let internal = e.take::<crate::errors::InternalError2>();
-        assert_eq!(internal.0, "query timeout");
-    }
-}

server/crates/arbiter-terrors-poc/src/errors.rs

@@ -1,130 +0,0 @@
-use terrors::OneOf;
-
-// Wire boundary type — what would go into a proto response
-#[derive(Debug)]
-pub enum ProtoError {
-    NotRegistered,
-    InvalidSignature,
-    Internal(String), // Or Box<dyn Error>, who cares?
-}
-
-// Internal terrors types
-#[derive(Debug)]
-pub struct NotRegistered;
-#[derive(Debug)]
-pub struct InvalidSignature;
-#[derive(Debug)]
-pub struct InternalError1(pub String);
-#[derive(Debug)]
-pub struct InternalError2(pub String);
-
-// Errors can be scattered across the codebase as long as they implement Into<ProtoError>
-impl From<NotRegistered> for ProtoError {
-    fn from(_: NotRegistered) -> Self {
-        ProtoError::NotRegistered
-    }
-}
-
-impl From<InvalidSignature> for ProtoError {
-    fn from(_: InvalidSignature) -> Self {
-        ProtoError::InvalidSignature
-    }
-}
-
-impl From<InternalError1> for ProtoError {
-    fn from(e: InternalError1) -> Self {
-        ProtoError::Internal(e.0)
-    }
-}
-impl From<InternalError2> for ProtoError {
-    fn from(e: InternalError2) -> Self {
-        ProtoError::Internal(e.0)
-    }
-}
-
-/// Private helper trait for converting from OneOf<T...> where each T can be converted
-/// into the target type `O` by recursively narrowing until a match is found.
-/// 
-/// IDK why this isn't already in terrors.
-trait DrainInto<O>: terrors::TypeSet + Sized {
-    fn drain(e: OneOf<Self>) -> O;
-}
-
-macro_rules! impl_drain_into {
-    ($head:ident) => {
-        impl<$head, O> DrainInto<O> for ($head,)
-        where
-            $head: Into<O> + 'static,
-        {
-            fn drain(e: OneOf<($head,)>) -> O {
-                e.take().into()
-            }
-        }
-    };
-    ($head:ident, $($tail:ident),+) => {
-        impl<$head, $($tail),+, O> DrainInto<O> for ($head, $($tail),+)
-        where
-            $head: Into<O> + 'static,
-            ($($tail,)+): DrainInto<O>,
-        {
-            fn drain(e: OneOf<($head, $($tail),+)>) -> O {
-                match e.narrow::<$head, _>() {
-                    Ok(h) => h.into(),
-                    Err(rest) => <($($tail,)+)>::drain(rest),
-                }
-            }
-        }
-        impl_drain_into!($($tail),+);
-    };
-}
-
-// Generates impls for all tuple sizes from 1 up to 7 (restricted by terrors internal impl).
-// Each invocation produces one impl then recurses on the tail.
-impl_drain_into!(A, B, C, D, E, F, G, H, I);
-
-// Blanket From impl: body delegates to the recursive drain.
-impl<E: DrainInto<ProtoError>> From<OneOf<E>> for ProtoError {
-    fn from(e: OneOf<E>) -> Self {
-        E::drain(e)
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn not_registered_converts_to_proto() {
-        let e: ProtoError = NotRegistered.into();
-        assert!(matches!(e, ProtoError::NotRegistered));
-    }
-
-    #[test]
-    fn invalid_signature_converts_to_proto() {
-        let e: ProtoError = InvalidSignature.into();
-        assert!(matches!(e, ProtoError::InvalidSignature));
-    }
-
-    #[test]
-    fn internal_converts_to_proto() {
-        let e: ProtoError = InternalError1("boom".into()).into();
-        assert!(matches!(e, ProtoError::Internal(msg) if msg == "boom"));
-    }
-
-    #[test]
-    fn one_of_remainder_converts_to_proto_invalid_signature() {
-        use terrors::OneOf;
-        let e: OneOf<(InvalidSignature, InternalError1)> = OneOf::new(InvalidSignature);
-        let proto = ProtoError::from(e);
-        assert!(matches!(proto, ProtoError::InvalidSignature));
-    }
-
-    #[test]
-    fn one_of_remainder_converts_to_proto_internal() {
-        use terrors::OneOf;
-        let e: OneOf<(InvalidSignature, InternalError1)> =
-            OneOf::new(InternalError1("db fail".into()));
-        let proto = ProtoError::from(e);
-        assert!(matches!(proto, ProtoError::Internal(msg) if msg == "db fail"));
-    }
-}

server/crates/arbiter-terrors-poc/src/main.rs

@@ -1,43 +0,0 @@
-mod auth;
-mod db;
-mod errors;
-
-use errors::ProtoError;
-
-fn run(id: u32, sig: &str) {
-    print!("authenticate(id={id}, sig={sig:?}) => ");
-    match auth::authenticate(id, sig) {
-        Ok(nonce) => println!("Ok(nonce={nonce})"),
-        Err(e) => match e.narrow::<errors::NotRegistered, _>() {
-            Ok(_) => println!("Err(NotRegistered) — handled locally"),
-            Err(remaining) => {
-                let proto = ProtoError::from(remaining);
-                println!("Err(ProtoError::{proto:?}) — forwarded to wire");
-            }
-        },
-    }
-}
-
-fn run_process(id: u32, sig: &str) {
-    print!("process_request(id={id}, sig={sig:?}) => ");
-    match auth::process_request(id, sig) {
-        Ok(s) => println!("Ok({s})"),
-        Err(e) => println!("Err(ProtoError::{e:?})"),
-    }
-}
-
-fn main() {
-    println!("=== authenticate ===");
-    run(0, "ok");   // NotRegistered
-    run(1, "bad");  // InvalidSignature
-    run(99, "ok");  // InternalError1
-    run(98, "ok");  // InternalError2
-    run(1, "ok");   // success
-
-    println!("\n=== process_request (Try chain) ===");
-    run_process(0, "ok");   // NotRegistered (guard, no I/O)
-    run_process(97, "ok");  // InternalError2 from load_config
-    run_process(99, "ok");  // InternalError1 from get_nonce
-    run_process(1, "bad");  // InvalidSignature from verify_signature
-    run_process(1, "ok");   // success
-}

server/crates/arbiter-useragent/Cargo.toml

@@ -1,29 +0,0 @@
-[package]
-name = "arbiter-useragent"
-version = "0.1.0"
-edition = "2024"
-license = "Apache-2.0"
-
-[lints]
-workspace = true
-
-[dependencies]
-arbiter-proto.path = "../arbiter-proto"
-kameo.workspace = true
-tokio = {workspace = true, features = ["net"]}
-tonic.workspace = true
-tonic.features = ["tls-aws-lc"]
-tracing.workspace = true
-ed25519-dalek.workspace = true
-smlang.workspace = true
-x25519-dalek.workspace = true
-k256.workspace = true
-rsa.workspace = true
-sha2.workspace = true
-spki.workspace = true
-rand.workspace = true
-thiserror.workspace = true
-tokio-stream.workspace = true
-http = "1.4.0"
-rustls-webpki = { version = "0.103.9", features = ["aws-lc-rs"] }
-async-trait.workspace = true

server/crates/arbiter-useragent/src/grpc.rs

@@ -1,70 +0,0 @@
-use arbiter_proto::{
-    proto::{
-        arbiter_service_client::ArbiterServiceClient,
-        user_agent::{UserAgentRequest, UserAgentResponse},
-    },
-    transport::{IdentityRecvConverter, IdentitySendConverter, grpc},
-    url::ArbiterUrl,
-};
-use kameo::actor::{ActorRef, Spawn};
-
-use tokio::sync::mpsc;
-use tokio_stream::wrappers::ReceiverStream;
-
-use tonic::transport::ClientTlsConfig;
-
-use super::{SigningKeyEnum, UserAgentActor};
-
-#[derive(Debug, thiserror::Error)]
-pub enum ConnectError {
-    #[error("Could establish connection")]
-    Connection(#[from] tonic::transport::Error),
-
-    #[error("Invalid server URI")]
-    InvalidUri(#[from] http::uri::InvalidUri),
-
-    #[error("Invalid CA certificate")]
-    InvalidCaCert(#[from] webpki::Error),
-
-    #[error("gRPC error")]
-    Grpc(#[from] tonic::Status),
-}
-
-pub type UserAgentGrpc = ActorRef<
-    UserAgentActor<
-        grpc::GrpcAdapter<
-            IdentityRecvConverter<UserAgentResponse>,
-            IdentitySendConverter<UserAgentRequest>,
-        >,
-    >,
->;
-pub async fn connect_grpc(
-    url: ArbiterUrl,
-    key: SigningKeyEnum,
-) -> Result<UserAgentGrpc, ConnectError> {
-    let bootstrap_token = url.bootstrap_token.clone();
-    let anchor = webpki::anchor_from_trusted_cert(&url.ca_cert)?.to_owned();
-    let tls = ClientTlsConfig::new().trust_anchor(anchor);
-
-    // TODO: if `host` is localhost, we need to verify server's process authenticity
-    let channel = tonic::transport::Channel::from_shared(format!("{}:{}", url.host, url.port))?
-        .tls_config(tls)?
-        .connect()
-        .await?;
-
-    let mut client = ArbiterServiceClient::new(channel);
-    let (tx, rx) = mpsc::channel(16);
-    let bistream = client.user_agent(ReceiverStream::new(rx)).await?;
-    let bistream = bistream.into_inner();
-
-    let adapter = grpc::GrpcAdapter::new(
-        tx,
-        bistream,
-        IdentityRecvConverter::new(),
-        IdentitySendConverter::new(),
-    );
-
-    let actor = UserAgentActor::spawn(UserAgentActor::new(key, bootstrap_token, adapter));
-
-    Ok(actor)
-}

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

@@ -1,257 +0,0 @@
-use arbiter_proto::{
-    format_challenge,
-    proto::user_agent::{
-        AuthChallengeRequest, AuthChallengeSolution, AuthOk, KeyType as ProtoKeyType,
-        UserAgentRequest, UserAgentResponse,
-        user_agent_request::Payload as UserAgentRequestPayload,
-        user_agent_response::Payload as UserAgentResponsePayload,
-    },
-    transport::Bi,
-};
-use kameo::{Actor, actor::ActorRef};
-use smlang::statemachine;
-use tokio::select;
-use tracing::{error, info};
-
-/// Signing key variants supported by the user-agent auth protocol.
-pub enum SigningKeyEnum {
-    Ed25519(ed25519_dalek::SigningKey),
-    /// secp256k1 ECDSA; public key is sent as SEC1 compressed 33 bytes; signature is raw 64-byte (r||s).
-    EcdsaSecp256k1(k256::ecdsa::SigningKey),
-    /// RSA for Windows Hello (KeyCredentialManager); public key is DER SPKI; signature is PSS+SHA-256.
-    Rsa(rsa::RsaPrivateKey),
-}
-
-impl SigningKeyEnum {
-    /// Returns the canonical public key bytes to include in `AuthChallengeRequest.pubkey`.
-    pub fn pubkey_bytes(&self) -> Vec<u8> {
-        match self {
-            SigningKeyEnum::Ed25519(k) => k.verifying_key().to_bytes().to_vec(),
-            // 33-byte SEC1 compressed point — compact and natively supported by secp256k1 tooling
-            SigningKeyEnum::EcdsaSecp256k1(k) => {
-                k.verifying_key().to_encoded_point(true).as_bytes().to_vec()
-            }
-            SigningKeyEnum::Rsa(k) => {
-                use rsa::pkcs8::EncodePublicKey as _;
-                k.to_public_key()
-                    .to_public_key_der()
-                    .expect("rsa SPKI encoding is infallible")
-                    .to_vec()
-            }
-        }
-    }
-
-    /// Returns the proto `KeyType` discriminant to send in `AuthChallengeRequest.key_type`.
-    pub fn proto_key_type(&self) -> ProtoKeyType {
-        match self {
-            SigningKeyEnum::Ed25519(_) => ProtoKeyType::Ed25519,
-            SigningKeyEnum::EcdsaSecp256k1(_) => ProtoKeyType::EcdsaSecp256k1,
-            SigningKeyEnum::Rsa(_) => ProtoKeyType::Rsa,
-        }
-    }
-
-    /// Signs `msg` and returns raw signature bytes matching the server-side verification.
-    pub fn sign(&self, msg: &[u8]) -> Vec<u8> {
-        match self {
-            SigningKeyEnum::Ed25519(k) => {
-                use ed25519_dalek::Signer as _;
-                k.sign(msg).to_bytes().to_vec()
-            }
-            SigningKeyEnum::EcdsaSecp256k1(k) => {
-                use k256::ecdsa::signature::Signer as _;
-                let sig: k256::ecdsa::Signature = k.sign(msg);
-                sig.to_bytes().to_vec()
-            }
-            SigningKeyEnum::Rsa(k) => {
-                use rsa::signature::RandomizedSigner as _;
-                let signing_key = rsa::pss::BlindedSigningKey::<sha2::Sha256>::new(k.clone());
-                // Use rand_core OsRng from the rsa crate's re-exported rand_core (0.6.x),
-                // which is the version rsa's signature API expects.
-                let sig = signing_key.sign_with_rng(&mut rsa::rand_core::OsRng, msg);
-                use rsa::signature::SignatureEncoding as _;
-                sig.to_vec()
-            }
-        }
-    }
-}
-
-statemachine! {
-    name: UserAgent,
-    custom_error: false,
-    transitions: {
-        *Init + SentAuthChallengeRequest = WaitingForServerAuth,
-        WaitingForServerAuth + ReceivedAuthChallenge = WaitingForAuthOk,
-        WaitingForServerAuth + ReceivedAuthOk = Authenticated,
-        WaitingForAuthOk + ReceivedAuthOk = Authenticated,
-    }
-}
-
-pub struct DummyContext;
-impl UserAgentStateMachineContext for DummyContext {}
-
-#[derive(Debug, thiserror::Error)]
-pub enum InboundError {
-    #[error("Invalid user agent response")]
-    InvalidResponse,
-    #[error("Expected response payload")]
-    MissingResponsePayload,
-    #[error("Unexpected response payload")]
-    UnexpectedResponsePayload,
-    #[error("Invalid state for auth challenge")]
-    InvalidStateForAuthChallenge,
-    #[error("Invalid state for auth ok")]
-    InvalidStateForAuthOk,
-    #[error("State machine error")]
-    StateTransitionFailed,
-    #[error("Transport send failed")]
-    TransportSendFailed,
-}
-
-pub struct UserAgentActor<Transport>
-where
-    Transport: Bi<UserAgentResponse, UserAgentRequest>,
-{
-    key: SigningKeyEnum,
-    bootstrap_token: Option<String>,
-    state: UserAgentStateMachine<DummyContext>,
-    transport: Transport,
-}
-
-impl<Transport> UserAgentActor<Transport>
-where
-    Transport: Bi<UserAgentResponse, UserAgentRequest>,
-{
-    pub fn new(key: SigningKeyEnum, bootstrap_token: Option<String>, transport: Transport) -> Self {
-        Self {
-            key,
-            bootstrap_token,
-            state: UserAgentStateMachine::new(DummyContext),
-            transport,
-        }
-    }
-
-    fn transition(&mut self, event: UserAgentEvents) -> Result<(), InboundError> {
-        self.state.process_event(event).map_err(|e| {
-            error!(?e, "useragent state transition failed");
-            InboundError::StateTransitionFailed
-        })?;
-        Ok(())
-    }
-
-    async fn send_auth_challenge_request(&mut self) -> Result<(), InboundError> {
-        let req = AuthChallengeRequest {
-            pubkey: self.key.pubkey_bytes(),
-            bootstrap_token: self.bootstrap_token.take(),
-            key_type: self.key.proto_key_type().into(),
-        };
-
-        self.transition(UserAgentEvents::SentAuthChallengeRequest)?;
-
-        self.transport
-            .send(UserAgentRequest {
-                payload: Some(UserAgentRequestPayload::AuthChallengeRequest(req)),
-            })
-            .await
-            .map_err(|_| InboundError::TransportSendFailed)?;
-
-        info!(actor = "useragent", "auth.request.sent");
-        Ok(())
-    }
-
-    async fn handle_auth_challenge(
-        &mut self,
-        challenge: arbiter_proto::proto::user_agent::AuthChallenge,
-    ) -> Result<(), InboundError> {
-        self.transition(UserAgentEvents::ReceivedAuthChallenge)?;
-
-        let formatted = format_challenge(challenge.nonce, &challenge.pubkey);
-        let signature_bytes = self.key.sign(&formatted);
-        let solution = AuthChallengeSolution {
-            signature: signature_bytes,
-        };
-
-        self.transport
-            .send(UserAgentRequest {
-                payload: Some(UserAgentRequestPayload::AuthChallengeSolution(solution)),
-            })
-            .await
-            .map_err(|_| InboundError::TransportSendFailed)?;
-
-        info!(actor = "useragent", "auth.solution.sent");
-        Ok(())
-    }
-
-    fn handle_auth_ok(&mut self, _ok: AuthOk) -> Result<(), InboundError> {
-        self.transition(UserAgentEvents::ReceivedAuthOk)?;
-        info!(actor = "useragent", "auth.ok");
-        Ok(())
-    }
-
-    pub async fn process_inbound_transport(
-        &mut self,
-        inbound: UserAgentResponse,
-    ) -> Result<(), InboundError> {
-        let payload = inbound
-            .payload
-            .ok_or(InboundError::MissingResponsePayload)?;
-
-        match payload {
-            UserAgentResponsePayload::AuthChallenge(challenge) => {
-                self.handle_auth_challenge(challenge).await
-            }
-            UserAgentResponsePayload::AuthOk(ok) => self.handle_auth_ok(ok),
-            _ => Err(InboundError::UnexpectedResponsePayload),
-        }
-    }
-}
-
-impl<Transport> Actor for UserAgentActor<Transport>
-where
-    Transport: Bi<UserAgentResponse, UserAgentRequest>,
-{
-    type Args = Self;
-
-    type Error = ();
-
-    async fn on_start(
-        mut args: Self::Args,
-        _actor_ref: ActorRef<Self>,
-    ) -> Result<Self, Self::Error> {
-        if let Err(err) = args.send_auth_challenge_request().await {
-            error!(?err, actor = "useragent", "auth.start.failed");
-            return Err(());
-        }
-        Ok(args)
-    }
-
-    async fn next(
-        &mut self,
-        _actor_ref: kameo::prelude::WeakActorRef<Self>,
-        mailbox_rx: &mut kameo::prelude::MailboxReceiver<Self>,
-    ) -> Option<kameo::mailbox::Signal<Self>> {
-        loop {
-            select! {
-                signal = mailbox_rx.recv() => {
-                    return signal;
-                }
-                inbound = self.transport.recv() => {
-                    match inbound {
-                        Some(inbound) => {
-                            if let Err(err) = self.process_inbound_transport(inbound).await {
-                                error!(?err, actor = "useragent", "transport.inbound.failed");
-                                return Some(kameo::mailbox::Signal::Stop);
-                            }
-                        }
-                        None => {
-                            info!(actor = "useragent", "transport.closed");
-                            return Some(kameo::mailbox::Signal::Stop);
-                        }
-                    }
-                }
-            }
-        }
-    }
-}
-
-mod grpc;
-pub use grpc::{ConnectError, connect_grpc};

server/crates/arbiter-useragent/tests/auth.rs

@@ -1,146 +0,0 @@
-use arbiter_proto::{
-    format_challenge,
-    proto::user_agent::{
-        AuthChallenge, AuthOk, UserAgentRequest, UserAgentResponse,
-        user_agent_request::Payload as UserAgentRequestPayload,
-        user_agent_response::Payload as UserAgentResponsePayload,
-    },
-    transport::Bi,
-};
-use arbiter_useragent::{SigningKeyEnum, UserAgentActor};
-use async_trait::async_trait;
-use ed25519_dalek::SigningKey;
-use kameo::actor::Spawn;
-use tokio::sync::mpsc;
-use tokio::time::{Duration, timeout};
-
-struct TestTransport {
-    inbound_rx: mpsc::Receiver<UserAgentResponse>,
-    outbound_tx: mpsc::Sender<UserAgentRequest>,
-}
-
-#[async_trait]
-impl Bi<UserAgentResponse, UserAgentRequest> for TestTransport {
-    async fn send(
-        &mut self,
-        item: UserAgentRequest,
-    ) -> Result<(), arbiter_proto::transport::Error> {
-        self.outbound_tx
-            .send(item)
-            .await
-            .map_err(|_| arbiter_proto::transport::Error::ChannelClosed)
-    }
-
-    async fn recv(&mut self) -> Option<UserAgentResponse> {
-        self.inbound_rx.recv().await
-    }
-}
-
-fn make_transport() -> (
-    TestTransport,
-    mpsc::Sender<UserAgentResponse>,
-    mpsc::Receiver<UserAgentRequest>,
-) {
-    let (inbound_tx, inbound_rx) = mpsc::channel(8);
-    let (outbound_tx, outbound_rx) = mpsc::channel(8);
-    (
-        TestTransport {
-            inbound_rx,
-            outbound_tx,
-        },
-        inbound_tx,
-        outbound_rx,
-    )
-}
-
-fn test_key() -> SigningKeyEnum {
-    SigningKeyEnum::Ed25519(SigningKey::from_bytes(&[7u8; 32]))
-}
-
-#[tokio::test]
-async fn sends_auth_request_on_start_with_bootstrap_token() {
-    let key = test_key();
-    let pubkey = key.pubkey_bytes();
-    let bootstrap_token = Some("bootstrap-123".to_string());
-    let (transport, inbound_tx, mut outbound_rx) = make_transport();
-
-    let actor = UserAgentActor::spawn(UserAgentActor::new(key, bootstrap_token.clone(), transport));
-
-    let outbound = timeout(Duration::from_secs(1), outbound_rx.recv())
-        .await
-        .expect("timed out waiting for auth request")
-        .expect("channel closed before auth request");
-
-    let UserAgentRequest {
-        payload: Some(UserAgentRequestPayload::AuthChallengeRequest(req)),
-    } = outbound
-    else {
-        panic!("expected auth challenge request");
-    };
-
-    assert_eq!(req.pubkey, pubkey);
-    assert_eq!(req.bootstrap_token, bootstrap_token);
-
-    drop(inbound_tx);
-    drop(actor);
-}
-
-#[tokio::test]
-async fn challenge_flow_sends_solution_from_transport_inbound() {
-    let key = test_key();
-    let pubkey_bytes = key.pubkey_bytes();
-    let (transport, inbound_tx, mut outbound_rx) = make_transport();
-
-    let actor = UserAgentActor::spawn(UserAgentActor::new(key, None, transport));
-
-    let _initial_auth_request = timeout(Duration::from_secs(1), outbound_rx.recv())
-        .await
-        .expect("timed out waiting for initial auth request")
-        .expect("missing initial auth request");
-
-    let challenge = AuthChallenge {
-        pubkey: pubkey_bytes.clone(),
-        nonce: 42,
-    };
-    inbound_tx
-        .send(UserAgentResponse {
-            payload: Some(UserAgentResponsePayload::AuthChallenge(challenge.clone())),
-        })
-        .await
-        .unwrap();
-
-    let outbound = timeout(Duration::from_secs(1), outbound_rx.recv())
-        .await
-        .expect("timed out waiting for challenge solution")
-        .expect("missing challenge solution");
-
-    let UserAgentRequest {
-        payload: Some(UserAgentRequestPayload::AuthChallengeSolution(solution)),
-    } = outbound
-    else {
-        panic!("expected auth challenge solution");
-    };
-
-    // Verify the signature using the Ed25519 verifying key
-    let formatted = format_challenge(challenge.nonce, &challenge.pubkey);
-    let raw_key = SigningKey::from_bytes(&[7u8; 32]);
-    let sig: ed25519_dalek::Signature = solution
-        .signature
-        .as_slice()
-        .try_into()
-        .expect("signature bytes length");
-    raw_key
-        .verifying_key()
-        .verify_strict(&formatted, &sig)
-        .expect("solution signature should verify");
-
-    inbound_tx
-        .send(UserAgentResponse {
-            payload: Some(UserAgentResponsePayload::AuthOk(AuthOk {})),
-        })
-        .await
-        .unwrap();
-
-    drop(inbound_tx);
-    drop(actor);
-}

server/rules/safecell/new-inline.yaml

@@ -0,0 +1,10 @@
+id: safecell-new-inline
+language: Rust
+rule:
+  pattern: $CELL.write_inline(|$W| $BODY);
+  follows:
+    pattern: let mut $CELL = SafeCell::new($INIT);
+fix: 
+  template: let mut $CELL = SafeCell::new_inline(|$W| $BODY);
+  expandStart:
+    pattern: let mut $CELL = SafeCell::new($INIT)

server/rules/safecell/read-inline.yaml

@@ -0,0 +1,17 @@
+id: safecell-read-inline
+language: Rust
+rule:
+  pattern: 
+    context: |
+      {
+          let $READ = $CELL.read();
+          $$$BODY
+      }
+    selector: block
+  inside:
+    kind: block
+fix: 
+  template: | 
+    $CELL.read_inline(|$READ| { 
+      $$$BODY 
+    });

server/rules/safecell/write-inline.yaml

@@ -0,0 +1,13 @@
+id: safecell-write-inline
+language: Rust
+rule:
+  pattern: |
+    {
+        let mut $WRITE = $CELL.write();
+        $$$BODY
+    }
+fix: 
+  template: | 
+    $CELL.write_inline(|$WRITE| { 
+      $$$BODY 
+    });

server/sgconfig.yml

@@ -0,0 +1,2 @@
+ruleDirs:
+- ./rules

useragent/.dart_tool/extension_discovery/README.md

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

useragent/.dart_tool/extension_discovery/vs_code.json

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

useragent/.dart_tool/package_config.json

@@ -1,172 +0,0 @@
-{
-  "configVersion": 2,
-  "packages": [
-    {
-      "name": "async",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/async-2.13.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "boolean_selector",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/boolean_selector-2.1.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "characters",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/characters-1.4.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "clock",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/clock-1.1.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "collection",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/collection-1.19.1",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "fake_async",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/fake_async-1.3.3",
-      "packageUri": "lib/",
-      "languageVersion": "3.3"
-    },
-    {
-      "name": "flutter",
-      "rootUri": "file:///Users/kaska/.local/share/mise/installs/flutter/3.38.9-stable/packages/flutter",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "flutter_lints",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/flutter_lints-6.0.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "flutter_test",
-      "rootUri": "file:///Users/kaska/.local/share/mise/installs/flutter/3.38.9-stable/packages/flutter_test",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "leak_tracker",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/leak_tracker-11.0.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.2"
-    },
-    {
-      "name": "leak_tracker_flutter_testing",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/leak_tracker_flutter_testing-3.0.10",
-      "packageUri": "lib/",
-      "languageVersion": "3.2"
-    },
-    {
-      "name": "leak_tracker_testing",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/leak_tracker_testing-3.0.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.2"
-    },
-    {
-      "name": "lints",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/lints-6.1.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "matcher",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/matcher-0.12.17",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "material_color_utilities",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/material_color_utilities-0.11.1",
-      "packageUri": "lib/",
-      "languageVersion": "2.17"
-    },
-    {
-      "name": "meta",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/meta-1.17.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.5"
-    },
-    {
-      "name": "path",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/path-1.9.1",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "sky_engine",
-      "rootUri": "file:///Users/kaska/.local/share/mise/installs/flutter/3.38.9-stable/bin/cache/pkg/sky_engine",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "source_span",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/source_span-1.10.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "stack_trace",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/stack_trace-1.12.1",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "stream_channel",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/stream_channel-2.1.4",
-      "packageUri": "lib/",
-      "languageVersion": "3.3"
-    },
-    {
-      "name": "string_scanner",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/string_scanner-1.4.1",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "term_glyph",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/term_glyph-1.2.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "test_api",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/test_api-0.7.7",
-      "packageUri": "lib/",
-      "languageVersion": "3.5"
-    },
-    {
-      "name": "vector_math",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/vector_math-2.2.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "vm_service",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/vm_service-15.0.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.5"
-    },
-    {
-      "name": "arbiter",
-      "rootUri": "../",
-      "packageUri": "lib/",
-      "languageVersion": "3.10"
-    }
-  ],
-  "generator": "pub",
-  "generatorVersion": "3.10.8",
-  "flutterRoot": "file:///Users/kaska/.local/share/mise/installs/flutter/3.38.9-stable",
-  "flutterVersion": "3.38.9",
-  "pubCache": "file:///Users/kaska/.pub-cache"
-}

useragent/.dart_tool/package_graph.json

@@ -1,224 +0,0 @@
-{
-  "roots": [
-    "arbiter"
-  ],
-  "packages": [
-    {
-      "name": "arbiter",
-      "version": "0.1.0",
-      "dependencies": [
-        "flutter"
-      ],
-      "devDependencies": [
-        "flutter_lints",
-        "flutter_test"
-      ]
-    },
-    {
-      "name": "flutter_lints",
-      "version": "6.0.0",
-      "dependencies": [
-        "lints"
-      ]
-    },
-    {
-      "name": "flutter_test",
-      "version": "0.0.0",
-      "dependencies": [
-        "clock",
-        "collection",
-        "fake_async",
-        "flutter",
-        "leak_tracker_flutter_testing",
-        "matcher",
-        "meta",
-        "path",
-        "stack_trace",
-        "stream_channel",
-        "test_api",
-        "vector_math"
-      ]
-    },
-    {
-      "name": "flutter",
-      "version": "0.0.0",
-      "dependencies": [
-        "characters",
-        "collection",
-        "material_color_utilities",
-        "meta",
-        "sky_engine",
-        "vector_math"
-      ]
-    },
-    {
-      "name": "lints",
-      "version": "6.1.0",
-      "dependencies": []
-    },
-    {
-      "name": "stream_channel",
-      "version": "2.1.4",
-      "dependencies": [
-        "async"
-      ]
-    },
-    {
-      "name": "meta",
-      "version": "1.17.0",
-      "dependencies": []
-    },
-    {
-      "name": "collection",
-      "version": "1.19.1",
-      "dependencies": []
-    },
-    {
-      "name": "leak_tracker_flutter_testing",
-      "version": "3.0.10",
-      "dependencies": [
-        "flutter",
-        "leak_tracker",
-        "leak_tracker_testing",
-        "matcher",
-        "meta"
-      ]
-    },
-    {
-      "name": "vector_math",
-      "version": "2.2.0",
-      "dependencies": []
-    },
-    {
-      "name": "stack_trace",
-      "version": "1.12.1",
-      "dependencies": [
-        "path"
-      ]
-    },
-    {
-      "name": "clock",
-      "version": "1.1.2",
-      "dependencies": []
-    },
-    {
-      "name": "fake_async",
-      "version": "1.3.3",
-      "dependencies": [
-        "clock",
-        "collection"
-      ]
-    },
-    {
-      "name": "path",
-      "version": "1.9.1",
-      "dependencies": []
-    },
-    {
-      "name": "matcher",
-      "version": "0.12.17",
-      "dependencies": [
-        "async",
-        "meta",
-        "stack_trace",
-        "term_glyph",
-        "test_api"
-      ]
-    },
-    {
-      "name": "test_api",
-      "version": "0.7.7",
-      "dependencies": [
-        "async",
-        "boolean_selector",
-        "collection",
-        "meta",
-        "source_span",
-        "stack_trace",
-        "stream_channel",
-        "string_scanner",
-        "term_glyph"
-      ]
-    },
-    {
-      "name": "sky_engine",
-      "version": "0.0.0",
-      "dependencies": []
-    },
-    {
-      "name": "material_color_utilities",
-      "version": "0.11.1",
-      "dependencies": [
-        "collection"
-      ]
-    },
-    {
-      "name": "characters",
-      "version": "1.4.0",
-      "dependencies": []
-    },
-    {
-      "name": "async",
-      "version": "2.13.0",
-      "dependencies": [
-        "collection",
-        "meta"
-      ]
-    },
-    {
-      "name": "leak_tracker_testing",
-      "version": "3.0.2",
-      "dependencies": [
-        "leak_tracker",
-        "matcher",
-        "meta"
-      ]
-    },
-    {
-      "name": "leak_tracker",
-      "version": "11.0.2",
-      "dependencies": [
-        "clock",
-        "collection",
-        "meta",
-        "path",
-        "vm_service"
-      ]
-    },
-    {
-      "name": "term_glyph",
-      "version": "1.2.2",
-      "dependencies": []
-    },
-    {
-      "name": "string_scanner",
-      "version": "1.4.1",
-      "dependencies": [
-        "source_span"
-      ]
-    },
-    {
-      "name": "source_span",
-      "version": "1.10.2",
-      "dependencies": [
-        "collection",
-        "path",
-        "term_glyph"
-      ]
-    },
-    {
-      "name": "boolean_selector",
-      "version": "2.1.2",
-      "dependencies": [
-        "source_span",
-        "string_scanner"
-      ]
-    },
-    {
-      "name": "vm_service",
-      "version": "15.0.2",
-      "dependencies": []
-    }
-  ],
-  "configVersion": 1
-}

useragent/.dart_tool/version

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

useragent/README.md

@@ -1,4 +1,4 @@
-# app
+# useragent
 
 A new Flutter project.
 

useragent/android/.gitignore

@@ -0,0 +1,14 @@
+gradle-wrapper.jar
+/.gradle
+/captures/
+/gradlew
+/gradlew.bat
+/local.properties
+GeneratedPluginRegistrant.java
+.cxx/
+
+# Remember to never publicly share your keystore.
+# See https://flutter.dev/to/reference-keystore
+key.properties
+**/*.keystore
+**/*.jks

useragent/android/app/build.gradle.kts

@@ -0,0 +1,44 @@
+plugins {
+    id("com.android.application")
+    id("kotlin-android")
+    // The Flutter Gradle Plugin must be applied after the Android and Kotlin Gradle plugins.
+    id("dev.flutter.flutter-gradle-plugin")
+}
+
+android {
+    namespace = "com.example.useragent"
+    compileSdk = flutter.compileSdkVersion
+    ndkVersion = flutter.ndkVersion
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+
+    kotlinOptions {
+        jvmTarget = JavaVersion.VERSION_17.toString()
+    }
+
+    defaultConfig {
+        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
+        applicationId = "com.example.useragent"
+        // You can update the following values to match your application needs.
+        // For more information, see: https://flutter.dev/to/review-gradle-config.
+        minSdk = flutter.minSdkVersion
+        targetSdk = flutter.targetSdkVersion
+        versionCode = flutter.versionCode
+        versionName = flutter.versionName
+    }
+
+    buildTypes {
+        release {
+            // TODO: Add your own signing config for the release build.
+            // Signing with the debug keys for now, so `flutter run --release` works.
+            signingConfig = signingConfigs.getByName("debug")
+        }
+    }
+}
+
+flutter {
+    source = "../.."
+}

useragent/android/app/src/debug/AndroidManifest.xml

@@ -0,0 +1,7 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- The INTERNET permission is required for development. Specifically,
+         the Flutter tool needs it to communicate with the running application
+         to allow setting breakpoints, to provide hot reload, etc.
+    -->
+    <uses-permission android:name="android.permission.INTERNET"/>
+</manifest>

useragent/android/app/src/main/AndroidManifest.xml

@@ -0,0 +1,45 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <application
+        android:label="useragent"
+        android:name="${applicationName}"
+        android:icon="@mipmap/ic_launcher">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true"
+            android:launchMode="singleTop"
+            android:taskAffinity=""
+            android:theme="@style/LaunchTheme"
+            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
+            android:hardwareAccelerated="true"
+            android:windowSoftInputMode="adjustResize">
+            <!-- Specifies an Android theme to apply to this Activity as soon as
+                 the Android process has started. This theme is visible to the user
+                 while the Flutter UI initializes. After that, this theme continues
+                 to determine the Window background behind the Flutter UI. -->
+            <meta-data
+              android:name="io.flutter.embedding.android.NormalTheme"
+              android:resource="@style/NormalTheme"
+              />
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN"/>
+                <category android:name="android.intent.category.LAUNCHER"/>
+            </intent-filter>
+        </activity>
+        <!-- Don't delete the meta-data below.
+             This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
+        <meta-data
+            android:name="flutterEmbedding"
+            android:value="2" />
+    </application>
+    <!-- Required to query activities that can process text, see:
+         https://developer.android.com/training/package-visibility and
+         https://developer.android.com/reference/android/content/Intent#ACTION_PROCESS_TEXT.
+
+         In particular, this is used by the Flutter engine in io.flutter.plugin.text.ProcessTextPlugin. -->
+    <queries>
+        <intent>
+            <action android:name="android.intent.action.PROCESS_TEXT"/>
+            <data android:mimeType="text/plain"/>
+        </intent>
+    </queries>
+</manifest>

useragent/android/app/src/main/kotlin/com/example/useragent/MainActivity.kt

@@ -0,0 +1,5 @@
+package com.example.useragent
+
+import io.flutter.embedding.android.FlutterActivity
+
+class MainActivity : FlutterActivity()

useragent/android/app/src/main/res/drawable-v21/launch_background.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Modify this file to customize your launch splash screen -->
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:drawable="?android:colorBackground" />
+
+    <!-- You can insert your own image assets here -->
+    <!-- <item>
+        <bitmap
+            android:gravity="center"
+            android:src="@mipmap/launch_image" />
+    </item> -->
+</layer-list>

useragent/android/app/src/main/res/drawable/launch_background.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Modify this file to customize your launch splash screen -->
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:drawable="@android:color/white" />
+
+    <!-- You can insert your own image assets here -->
+    <!-- <item>
+        <bitmap
+            android:gravity="center"
+            android:src="@mipmap/launch_image" />
+    </item> -->
+</layer-list>

useragent/android/app/src/main/res/values-night/styles.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <!-- Theme applied to the Android Window while the process is starting when the OS's Dark Mode setting is on -->
+    <style name="LaunchTheme" parent="@android:style/Theme.Black.NoTitleBar">
+        <!-- Show a splash screen on the activity. Automatically removed when
+             the Flutter engine draws its first frame -->
+        <item name="android:windowBackground">@drawable/launch_background</item>
+    </style>
+    <!-- Theme applied to the Android Window as soon as the process has started.
+         This theme determines the color of the Android Window while your
+         Flutter UI initializes, as well as behind your Flutter UI while its
+         running.
+
+         This Theme is only used starting with V2 of Flutter's Android embedding. -->
+    <style name="NormalTheme" parent="@android:style/Theme.Black.NoTitleBar">
+        <item name="android:windowBackground">?android:colorBackground</item>
+    </style>
+</resources>

useragent/android/app/src/main/res/values/styles.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <!-- Theme applied to the Android Window while the process is starting when the OS's Dark Mode setting is off -->
+    <style name="LaunchTheme" parent="@android:style/Theme.Light.NoTitleBar">
+        <!-- Show a splash screen on the activity. Automatically removed when
+             the Flutter engine draws its first frame -->
+        <item name="android:windowBackground">@drawable/launch_background</item>
+    </style>
+    <!-- Theme applied to the Android Window as soon as the process has started.
+         This theme determines the color of the Android Window while your
+         Flutter UI initializes, as well as behind your Flutter UI while its
+         running.
+
+         This Theme is only used starting with V2 of Flutter's Android embedding. -->
+    <style name="NormalTheme" parent="@android:style/Theme.Light.NoTitleBar">
+        <item name="android:windowBackground">?android:colorBackground</item>
+    </style>
+</resources>

useragent/android/app/src/profile/AndroidManifest.xml

@@ -0,0 +1,7 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- The INTERNET permission is required for development. Specifically,
+         the Flutter tool needs it to communicate with the running application
+         to allow setting breakpoints, to provide hot reload, etc.
+    -->
+    <uses-permission android:name="android.permission.INTERNET"/>
+</manifest>

useragent/android/build.gradle.kts

@@ -0,0 +1,24 @@
+allprojects {
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+val newBuildDir: Directory =
+    rootProject.layout.buildDirectory
+        .dir("../../build")
+        .get()
+rootProject.layout.buildDirectory.value(newBuildDir)
+
+subprojects {
+    val newSubprojectBuildDir: Directory = newBuildDir.dir(project.name)
+    project.layout.buildDirectory.value(newSubprojectBuildDir)
+}
+subprojects {
+    project.evaluationDependsOn(":app")
+}
+
+tasks.register<Delete>("clean") {
+    delete(rootProject.layout.buildDirectory)
+}

useragent/android/gradle.properties

@@ -0,0 +1,2 @@
+org.gradle.jvmargs=-Xmx8G -XX:MaxMetaspaceSize=4G -XX:ReservedCodeCacheSize=512m -XX:+HeapDumpOnOutOfMemoryError
+android.useAndroidX=true

useragent/android/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.14-all.zip

useragent/android/settings.gradle.kts

@@ -0,0 +1,26 @@
+pluginManagement {
+    val flutterSdkPath =
+        run {
+            val properties = java.util.Properties()
+            file("local.properties").inputStream().use { properties.load(it) }
+            val flutterSdkPath = properties.getProperty("flutter.sdk")
+            require(flutterSdkPath != null) { "flutter.sdk not set in local.properties" }
+            flutterSdkPath
+        }
+
+    includeBuild("$flutterSdkPath/packages/flutter_tools/gradle")
+
+    repositories {
+        google()
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+
+plugins {
+    id("dev.flutter.flutter-plugin-loader") version "1.0.0"
+    id("com.android.application") version "8.11.1" apply false
+    id("org.jetbrains.kotlin.android") version "2.2.20" apply false
+}
+
+include(":app")

useragent/lib/features/connection/arbiter_url.dart

@@ -0,0 +1,56 @@
+import 'dart:convert';
+
+class ArbiterUrl {
+  const ArbiterUrl({
+    required this.host,
+    required this.port,
+    required this.caCert,
+    this.bootstrapToken,
+  });
+
+  final String host;
+  final int port;
+  final List<int> caCert;
+  final String? bootstrapToken;
+
+  static const _scheme = 'arbiter';
+  static const _certQueryKey = 'cert';
+  static const _bootstrapTokenQueryKey = 'bootstrap_token';
+
+  static ArbiterUrl parse(String value) {
+    final uri = Uri.tryParse(value);
+    if (uri == null || uri.scheme != _scheme) {
+      throw const FormatException("Invalid URL scheme, expected 'arbiter://'");
+    }
+
+    if (uri.host.isEmpty) {
+      throw const FormatException('Missing host in URL');
+    }
+
+    if (!uri.hasPort) {
+      throw const FormatException('Missing port in URL');
+    }
+
+    final cert = uri.queryParameters[_certQueryKey];
+    if (cert == null || cert.isEmpty) {
+      throw const FormatException("Missing 'cert' query parameter in URL");
+    }
+
+    final decodedCert = _decodeCert(cert);
+
+    return ArbiterUrl(
+      host: uri.host,
+      port: uri.port,
+      caCert: decodedCert,
+      bootstrapToken: uri.queryParameters[_bootstrapTokenQueryKey],
+    );
+  }
+
+  static List<int> _decodeCert(String cert) {
+    try {
+      return base64Url.decode(base64Url.normalize(cert));
+    } on FormatException catch (error) {
+      throw FormatException("Invalid base64 in 'cert' query parameter: ${error.message}");
+    }
+  }
+}

useragent/lib/features/connection/auth.dart

@@ -0,0 +1,103 @@
+import 'dart:async';
+import 'dart:convert';
+
+import 'package:arbiter/features/connection/connection.dart';
+import 'package:arbiter/features/connection/server_info_storage.dart';
+import 'package:arbiter/features/identity/pk_manager.dart';
+import 'package:arbiter/proto/arbiter.pbgrpc.dart';
+import 'package:arbiter/proto/user_agent.pb.dart';
+import 'package:grpc/grpc.dart';
+import 'package:mtcore/markettakers.dart';
+
+Future<Connection> connectAndAuthorize(
+  StoredServerInfo serverInfo,
+  KeyHandle key, {
+  String? bootstrapToken,
+}) async {
+  try {
+    final connection = await _connect(serverInfo);
+    talker.info(
+      'Connected to server at ${serverInfo.address}:${serverInfo.port}',
+    );
+    final pubkey = await key.getPublicKey();
+
+    final req = AuthChallengeRequest(
+      pubkey: pubkey,
+      bootstrapToken: bootstrapToken,
+      keyType: switch (key.alg) {
+        KeyAlgorithm.rsa => KeyType.KEY_TYPE_RSA,
+        KeyAlgorithm.ecdsa => KeyType.KEY_TYPE_ECDSA_SECP256K1,
+        KeyAlgorithm.ed25519 => KeyType.KEY_TYPE_ED25519,
+      },
+    );
+    await connection.send(UserAgentRequest(authChallengeRequest: req));
+    talker.info(
+      "Sent auth challenge request with pubkey ${base64Encode(pubkey)}",
+    );
+
+    final response = await connection.receive();
+    talker.info('Received response from server, checking auth flow...');
+
+    if (response.hasAuthOk()) {
+      talker.info('Authentication successful, connection established');
+      return connection;
+    }
+
+    if (!response.hasAuthChallenge()) {
+      throw Exception(
+        'Expected AuthChallengeResponse, got ${response.whichPayload()}',
+      );
+    }
+
+    final challenge = _formatChallenge(response.authChallenge, pubkey);
+    talker.info(
+      'Received auth challenge, signing with key ${base64Encode(pubkey)}',
+    );
+
+    final signature = await key.sign(challenge);
+    await connection.send(
+      UserAgentRequest(authChallengeSolution: AuthChallengeSolution(signature: signature)),
+    );
+
+    talker.info('Sent auth challenge solution, waiting for server response...');
+
+    final solutionResponse = await connection.receive();
+    if (!solutionResponse.hasAuthOk()) {
+      throw Exception(
+        'Expected AuthChallengeSolutionResponse, got ${solutionResponse.whichPayload()}',
+      );
+    }
+
+    talker.info('Authentication successful, connection established');
+    return connection;
+  } catch (e) {
+    throw Exception('Failed to connect to server: $e');
+  }
+}
+
+Future<Connection> _connect(StoredServerInfo serverInfo) async {
+  final channel = ClientChannel(
+    serverInfo.address,
+    port: serverInfo.port,
+    options: ChannelOptions(
+      connectTimeout: const Duration(seconds: 10),
+      credentials: ChannelCredentials.secure(
+        onBadCertificate: (cert, host) {
+          return true;
+        },
+      ),
+    ),
+  );
+
+  final client = ArbiterServiceClient(channel);
+  final tx = StreamController<UserAgentRequest>();
+  final rx = client.userAgent(tx.stream);
+
+  return Connection(channel: channel, tx: tx, rx: rx);
+}
+
+List<int> _formatChallenge(AuthChallenge challenge, List<int> pubkey) {
+  final encodedPubkey = base64Encode(pubkey);
+  final payload = "${challenge.nonce}:$encodedPubkey";
+  return utf8.encode(payload);
+}

useragent/lib/features/connection/connection.dart

@@ -0,0 +1,37 @@
+import 'dart:async';
+
+import 'package:arbiter/proto/user_agent.pb.dart';
+import 'package:grpc/grpc.dart';
+import 'package:mtcore/markettakers.dart';
+
+class Connection {
+  final ClientChannel channel;
+  final StreamController<UserAgentRequest> _tx;
+  final StreamIterator<UserAgentResponse> _rx;
+
+  Connection({
+    required this.channel,
+    required StreamController<UserAgentRequest> tx,
+    required ResponseStream<UserAgentResponse> rx,
+  }) : _tx = tx,
+       _rx = StreamIterator(rx);
+
+  Future<void> send(UserAgentRequest request) async {
+    talker.debug('Sending request: ${request.toDebugString()}');
+    _tx.add(request);
+  }
+
+  Future<UserAgentResponse> receive() async {
+    final hasValue = await _rx.moveNext();
+    if (!hasValue) {
+      throw Exception('Connection closed while waiting for server response.');
+    }
+    talker.debug('Received response: ${_rx.current.toDebugString()}');
+    return _rx.current;
+  }
+
+  Future<void> close() async {
+    await _tx.close();
+    await channel.shutdown();
+  }
+}

useragent/lib/features/connection/evm.dart

@@ -0,0 +1,56 @@
+import 'package:arbiter/features/connection/connection.dart';
+import 'package:arbiter/proto/evm.pb.dart';
+import 'package:arbiter/proto/user_agent.pb.dart';
+import 'package:protobuf/well_known_types/google/protobuf/empty.pb.dart';
+
+Future<List<WalletEntry>> listEvmWallets(Connection connection) async {
+  await connection.send(UserAgentRequest(evmWalletList: Empty()));
+
+  final response = await connection.receive();
+  if (!response.hasEvmWalletList()) {
+    throw Exception(
+      'Expected EVM wallet list response, got ${response.whichPayload()}',
+    );
+  }
+
+  final result = response.evmWalletList;
+  switch (result.whichResult()) {
+    case WalletListResponse_Result.wallets:
+      return result.wallets.wallets.toList(growable: false);
+    case WalletListResponse_Result.error:
+      throw Exception(_describeEvmError(result.error));
+    case WalletListResponse_Result.notSet:
+      throw Exception('EVM wallet list response was empty.');
+  }
+}
+
+Future<void> createEvmWallet(Connection connection) async {
+  await connection.send(UserAgentRequest(evmWalletCreate: Empty()));
+
+  final response = await connection.receive();
+  if (!response.hasEvmWalletCreate()) {
+    throw Exception(
+      'Expected EVM wallet create response, got ${response.whichPayload()}',
+    );
+  }
+
+  final result = response.evmWalletCreate;
+  switch (result.whichResult()) {
+    case WalletCreateResponse_Result.wallet:
+      return;
+    case WalletCreateResponse_Result.error:
+      throw Exception(_describeEvmError(result.error));
+    case WalletCreateResponse_Result.notSet:
+      throw Exception('Wallet creation returned no result.');
+  }
+}
+
+String _describeEvmError(EvmError error) {
+  return switch (error) {
+    EvmError.EVM_ERROR_VAULT_SEALED =>
+      'The vault is sealed. Unseal it before using EVM wallets.',
+    EvmError.EVM_ERROR_INTERNAL || EvmError.EVM_ERROR_UNSPECIFIED =>
+      'The server failed to process the EVM request.',
+    _ => 'The server failed to process the EVM request.',
+  };
+}

useragent/lib/features/connection/evm/grants.dart

@@ -0,0 +1,122 @@
+import 'package:arbiter/features/connection/connection.dart';
+import 'package:arbiter/proto/evm.pb.dart';
+import 'package:arbiter/proto/user_agent.pb.dart';
+import 'package:fixnum/fixnum.dart';
+import 'package:protobuf/well_known_types/google/protobuf/timestamp.pb.dart';
+
+Future<List<GrantEntry>> listEvmGrants(
+  Connection connection, {
+  int? walletId,
+}) async {
+  final request = EvmGrantListRequest();
+  if (walletId != null) {
+    request.walletId = walletId;
+  }
+
+  await connection.send(UserAgentRequest(evmGrantList: request));
+
+  final response = await connection.receive();
+  if (!response.hasEvmGrantList()) {
+    throw Exception(
+      'Expected EVM grant list response, got ${response.whichPayload()}',
+    );
+  }
+
+  final result = response.evmGrantList;
+  switch (result.whichResult()) {
+    case EvmGrantListResponse_Result.grants:
+      return result.grants.grants.toList(growable: false);
+    case EvmGrantListResponse_Result.error:
+      throw Exception(_describeGrantError(result.error));
+    case EvmGrantListResponse_Result.notSet:
+      throw Exception('EVM grant list response was empty.');
+  }
+}
+
+Future<int> createEvmGrant(
+  Connection connection, {
+  required int clientId,
+  required int walletId,
+  required Int64 chainId,
+  DateTime? validFrom,
+  DateTime? validUntil,
+  List<int>? maxGasFeePerGas,
+  List<int>? maxPriorityFeePerGas,
+  TransactionRateLimit? rateLimit,
+  required SpecificGrant specific,
+}) async {
+  await connection.send(
+    UserAgentRequest(
+      evmGrantCreate: EvmGrantCreateRequest(
+        clientId: clientId,
+        shared: SharedSettings(
+          walletId: walletId,
+          chainId: chainId,
+          validFrom: validFrom == null ? null : _toTimestamp(validFrom),
+          validUntil: validUntil == null ? null : _toTimestamp(validUntil),
+          maxGasFeePerGas: maxGasFeePerGas,
+          maxPriorityFeePerGas: maxPriorityFeePerGas,
+          rateLimit: rateLimit,
+        ),
+        specific: specific,
+      ),
+    ),
+  );
+
+  final response = await connection.receive();
+  if (!response.hasEvmGrantCreate()) {
+    throw Exception(
+      'Expected EVM grant create response, got ${response.whichPayload()}',
+    );
+  }
+
+  final result = response.evmGrantCreate;
+  switch (result.whichResult()) {
+    case EvmGrantCreateResponse_Result.grantId:
+      return result.grantId;
+    case EvmGrantCreateResponse_Result.error:
+      throw Exception(_describeGrantError(result.error));
+    case EvmGrantCreateResponse_Result.notSet:
+      throw Exception('Grant creation returned no result.');
+  }
+}
+
+Future<void> deleteEvmGrant(Connection connection, int grantId) async {
+  await connection.send(
+    UserAgentRequest(evmGrantDelete: EvmGrantDeleteRequest(grantId: grantId)),
+  );
+
+  final response = await connection.receive();
+  if (!response.hasEvmGrantDelete()) {
+    throw Exception(
+      'Expected EVM grant delete response, got ${response.whichPayload()}',
+    );
+  }
+
+  final result = response.evmGrantDelete;
+  switch (result.whichResult()) {
+    case EvmGrantDeleteResponse_Result.ok:
+      return;
+    case EvmGrantDeleteResponse_Result.error:
+      throw Exception(_describeGrantError(result.error));
+    case EvmGrantDeleteResponse_Result.notSet:
+      throw Exception('Grant revoke returned no result.');
+  }
+}
+
+Timestamp _toTimestamp(DateTime value) {
+  final utc = value.toUtc();
+  return Timestamp()
+    ..seconds = Int64(utc.millisecondsSinceEpoch ~/ 1000)
+    ..nanos = (utc.microsecondsSinceEpoch % 1000000) * 1000;
+}
+
+String _describeGrantError(EvmError error) {
+  return switch (error) {
+    EvmError.EVM_ERROR_VAULT_SEALED =>
+      'The vault is sealed. Unseal it before using EVM grants.',
+    EvmError.EVM_ERROR_INTERNAL || EvmError.EVM_ERROR_UNSPECIFIED =>
+      'The server failed to process the EVM grant request.',
+    _ => 'The server failed to process the EVM grant request.',
+  };
+}

useragent/lib/features/connection/server_info_storage.dart

@@ -0,0 +1,62 @@
+import 'dart:convert';
+
+import 'package:flutter_secure_storage/flutter_secure_storage.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+part 'server_info_storage.g.dart';
+
+@JsonSerializable()
+class StoredServerInfo {
+  const StoredServerInfo({
+    required this.address,
+    required this.port,
+    required this.caCertFingerprint,
+  });
+
+  final String address;
+  final int port;
+  final String caCertFingerprint;
+
+  factory StoredServerInfo.fromJson(Map<String, dynamic> json) => _$StoredServerInfoFromJson(json);
+  Map<String, dynamic> toJson() => _$StoredServerInfoToJson(this);
+  
+}
+
+abstract class ServerInfoStorage {
+  Future<StoredServerInfo?> load();
+  Future<void> save(StoredServerInfo serverInfo);
+  Future<void> clear();
+}
+
+class SecureServerInfoStorage implements ServerInfoStorage {
+  static const _storageKey = 'server_info';
+
+  const SecureServerInfoStorage();
+
+  static const _storage = FlutterSecureStorage();
+
+  @override
+  Future<StoredServerInfo?> load() async {
+    return null;
+    final rawValue = await _storage.read(key: _storageKey);
+    if (rawValue == null) {
+      return null;
+    }
+
+    final decoded = jsonDecode(rawValue) as Map<String, dynamic>;
+    return StoredServerInfo.fromJson(decoded);
+  }
+
+  @override
+  Future<void> save(StoredServerInfo serverInfo) {
+    return _storage.write(
+      key: _storageKey,
+      value: jsonEncode(serverInfo.toJson()),
+    );
+  }
+
+  @override
+  Future<void> clear() {
+    return _storage.delete(key: _storageKey);
+  }
+}

useragent/lib/features/connection/server_info_storage.g.dart

@@ -0,0 +1,21 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'server_info_storage.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+StoredServerInfo _$StoredServerInfoFromJson(Map<String, dynamic> json) =>
+    StoredServerInfo(
+      address: json['address'] as String,
+      port: (json['port'] as num).toInt(),
+      caCertFingerprint: json['caCertFingerprint'] as String,
+    );
+
+Map<String, dynamic> _$StoredServerInfoToJson(StoredServerInfo instance) =>
+    <String, dynamic>{
+      'address': instance.address,
+      'port': instance.port,
+      'caCertFingerprint': instance.caCertFingerprint,
+    };

useragent/lib/features/connection/vault.dart

@@ -0,0 +1,107 @@
+import 'package:arbiter/features/connection/connection.dart';
+import 'package:arbiter/proto/user_agent.pb.dart';
+import 'package:cryptography/cryptography.dart';
+
+const _vaultKeyAssociatedData = 'arbiter.vault.password';
+
+Future<BootstrapResult> bootstrapVault(
+  Connection connection,
+  String password,
+) async {
+  final encryptedKey = await _encryptVaultKeyMaterial(connection, password);
+
+  await connection.send(
+    UserAgentRequest(
+      bootstrapEncryptedKey: BootstrapEncryptedKey(
+        nonce: encryptedKey.nonce,
+        ciphertext: encryptedKey.ciphertext,
+        associatedData: encryptedKey.associatedData,
+      ),
+    ),
+  );
+
+  final response = await connection.receive();
+  if (!response.hasBootstrapResult()) {
+    throw Exception(
+      'Expected bootstrap result, got ${response.whichPayload()}',
+    );
+  }
+
+  return response.bootstrapResult;
+}
+
+Future<UnsealResult> unsealVault(Connection connection, String password) async {
+  final encryptedKey = await _encryptVaultKeyMaterial(connection, password);
+
+  await connection.send(
+    UserAgentRequest(
+      unsealEncryptedKey: UnsealEncryptedKey(
+        nonce: encryptedKey.nonce,
+        ciphertext: encryptedKey.ciphertext,
+        associatedData: encryptedKey.associatedData,
+      ),
+    ),
+  );
+
+  final response = await connection.receive();
+  if (!response.hasUnsealResult()) {
+    throw Exception('Expected unseal result, got ${response.whichPayload()}');
+  }
+
+  return response.unsealResult;
+}
+
+Future<_EncryptedVaultKey> _encryptVaultKeyMaterial(
+  Connection connection,
+  String password,
+) async {
+  final keyExchange = X25519();
+  final cipher = Xchacha20.poly1305Aead();
+  final clientKeyPair = await keyExchange.newKeyPair();
+  final clientPublicKey = await clientKeyPair.extractPublicKey();
+
+  await connection.send(
+    UserAgentRequest(unsealStart: UnsealStart(clientPubkey: clientPublicKey.bytes)),
+  );
+
+  final handshakeResponse = await connection.receive();
+  if (!handshakeResponse.hasUnsealStartResponse()) {
+    throw Exception(
+      'Expected unseal handshake response, got ${handshakeResponse.whichPayload()}',
+    );
+  }
+
+  final serverPublicKey = SimplePublicKey(
+    handshakeResponse.unsealStartResponse.serverPubkey,
+    type: KeyPairType.x25519,
+  );
+  final sharedSecret = await keyExchange.sharedSecretKey(
+    keyPair: clientKeyPair,
+    remotePublicKey: serverPublicKey,
+  );
+
+  final secretBox = await cipher.encrypt(
+    password.codeUnits,
+    secretKey: sharedSecret,
+    nonce: cipher.newNonce(),
+    aad: _vaultKeyAssociatedData.codeUnits,
+  );
+
+  return _EncryptedVaultKey(
+    nonce: secretBox.nonce,
+    ciphertext: [...secretBox.cipherText, ...secretBox.mac.bytes],
+    associatedData: _vaultKeyAssociatedData.codeUnits,
+  );
+}
+
+class _EncryptedVaultKey {
+  const _EncryptedVaultKey({
+    required this.nonce,
+    required this.ciphertext,
+    required this.associatedData,
+  });
+
+  final List<int> nonce;
+  final List<int> ciphertext;
+  final List<int> associatedData;
+}

useragent/lib/features/identity/pk_manager.dart

@@ -0,0 +1,16 @@
+enum KeyAlgorithm {
+  rsa, ecdsa, ed25519
+}
+
+// The API to handle without storing the private key in memory. 
+//The implementation will use platform-specific secure storage and signing capabilities.
+abstract class KeyHandle {
+  KeyAlgorithm get alg;
+  Future<List<int>> sign(List<int> data);
+  Future<List<int>> getPublicKey();
+}
+
+abstract class KeyManager {
+  Future<KeyHandle?> get();
+  Future<KeyHandle> create();
+}