merge: feat-lints into main

Reviewed-on: #90

AGENTS.md

@@ -66,7 +66,7 @@ cargo insta review
 The server is actor-based using the **kameo** crate. All long-lived state lives in `GlobalActors`:
 
 - **`Bootstrapper`** — Manages the one-time bootstrap token written to `~/.arbiter/bootstrap_token` on first run.
-- **`KeyHolder`** — Holds the encrypted root key and manages the Sealed/Unsealed vault state machine. On unseal, decrypts the root key into a `memsafe` hardened memory cell.
+- **`Vault`** — Holds the encrypted root key and manages the Sealed/Unsealed vault state machine. On unseal, decrypts the root key into a `memsafe` hardened memory cell.
 - **`FlowCoordinator`** — Coordinates cross-connection flow between user agents and SDK clients.
 - **`EvmActor`** — Handles EVM transaction policy enforcement and signing.
 
@@ -100,6 +100,27 @@ diesel migration generate <name> --migration-dir crates/arbiter-server/migration
 diesel migration run --migration-dir crates/arbiter-server/migrations
 ```
 
+### Code Conventions
+
+**`#[must_use]` Attribute:**
+Apply the `#[must_use]` attribute to return types of functions where the return value is critical and should not be accidentally ignored. This is commonly used for:
+
+- Methods that return `bool` indicating success/failure or validation state
+- Any function where ignoring the return value indicates a logic error
+
+Do not apply `#[must_use]` redundantly to items (types or functions) that are already annotated with `#[must_use]`.
+
+Example:
+
+```rust
+#[must_use]
+pub fn verify(&self, nonce: i32, context: &[u8], signature: &Signature) -> bool {
+    // verification logic
+}
+```
+
+This forces callers to either use the return value or explicitly ignore it with `let _ = ...;`, preventing silent failures.
+
 ## 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.

CLAUDE.md

@@ -66,7 +66,7 @@ cargo insta review
 The server is actor-based using the **kameo** crate. All long-lived state lives in `GlobalActors`:
 
 - **`Bootstrapper`** — Manages the one-time bootstrap token written to `~/.arbiter/bootstrap_token` on first run.
-- **`KeyHolder`** — Holds the encrypted root key and manages the Sealed/Unsealed vault state machine. On unseal, decrypts the root key into a `memsafe` hardened memory cell.
+- **`Vault`** — Holds the encrypted root key and manages the Sealed/Unsealed vault state machine. On unseal, decrypts the root key into a `memsafe` hardened memory cell.
 - **`FlowCoordinator`** — Coordinates cross-connection flow between user agents and SDK clients.
 - **`EvmActor`** — Handles EVM transaction policy enforcement and signing.
 
@@ -100,6 +100,27 @@ diesel migration generate <name> --migration-dir crates/arbiter-server/migration
 diesel migration run --migration-dir crates/arbiter-server/migrations
 ```
 
+### Code Conventions
+
+**`#[must_use]` Attribute:**
+Apply the `#[must_use]` attribute to return types of functions where the return value is critical and should not be accidentally ignored. This is commonly used for:
+
+- Methods that return `bool` indicating success/failure or validation state
+- Any function where ignoring the return value indicates a logic error
+
+Do not apply `#[must_use]` redundantly to items (types or functions) that are already annotated with `#[must_use]`.
+
+Example:
+
+```rust
+#[must_use]
+pub fn verify(&self, nonce: i32, context: &[u8], signature: &Signature) -> bool {
+    // verification logic
+}
+```
+
+This forces callers to either use the return value or explicitly ignore it with `let _ = ...;`, preventing silent failures.
+
 ## 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.

IMPLEMENTATION.md

@@ -29,38 +29,23 @@ flowchart TD
     A([Client connects]) --> B[Receive AuthChallengeRequest]
     B --> C{pubkey in DB?}
 
-    C -- yes --> D[Read nonce\nIncrement nonce in DB]
-    D --> G
+    C -- yes --> G[Generate AuthChallenge]
 
     C -- no --> E[Ask all UserAgents:\nClientConnectionRequest]
     E --> F{First response}
     F -- denied --> Z([Reject connection])
     F -- approved --> F2[Cancel remaining\nUserAgent requests]
-    F2 --> F3[INSERT client\nnonce = 1]
-    F3 --> G[Send AuthChallenge\nwith nonce]
+    F2 --> F3[INSERT client]
+    F3 --> G
 
-    G --> H[Receive AuthChallengeSolution]
-    H --> I{Signature valid?}
-    I -- no --> Z
-    I -- yes --> J([Session started])
+    G --> H[Send AuthChallenge\ntimestamp + random bytes]
+    H --> I[Receive AuthChallengeSolution]
+    I --> K{Signature valid?}
+    K -- no --> Z
+    K -- yes --> J([Session started])
 ```
 
-### Known Issue: Concurrent Registration Race (TOCTOU)
-
-Two connections presenting the same previously-unknown public key can race through the approval flow simultaneously:
-
-1. Both check the DB → neither is registered.
-2. Both request approval from user agents → both receive approval.
-3. Both `INSERT` the client record → the second insert silently overwrites the first, resetting the nonce.
-
-This means the first connection's nonce is invalidated by the second, causing its challenge verification to fail. A fix requires either serialising new-client registration (e.g. an in-memory lock keyed on pubkey) or replacing the separate check + insert with an `INSERT OR IGNORE` / upsert guarded by a unique constraint on `public_key`.
-
-### Nonce Semantics
-
-The `program_client.nonce` column stores the **next usable nonce** — i.e. it is always one ahead of the nonce last issued in a challenge.
-
-- **New client:** inserted with `nonce = 1`; the first challenge is issued with `nonce = 0`.
-- **Existing client:** the current DB value is read and used as the challenge nonce, then immediately incremented within the same exclusive transaction, preventing replay.
+Auth challenges are generated from fresh random bytes plus a timestamp. They are signed as the canonical challenge payload and are not persisted in `program_client`.
 
 ---
 

mise.lock

@@ -72,6 +72,10 @@ backend = "cargo:diesel_cli"
 default-features = "false"
 features = "sqlite,sqlite-bundled"
 
+[[tools."cargo:flutter_rust_bridge_codegen"]]
+version = "2.12.0"
+backend = "cargo:flutter_rust_bridge_codegen"
+
 [[tools.flutter]]
 version = "3.38.9-stable"
 backend = "asdf:flutter"

mise.toml

@@ -4,7 +4,7 @@
 "cargo:cargo-vet" = "0.10.2"
 flutter = "3.38.9-stable"
 protoc = "29.6"
-"rust" = {version = "1.93.0", components = "clippy"}
+"rust" = {version = "1.93.0", components = "clippy,rust-analyzer"}
 "cargo:cargo-features-manager" = "0.11.1"
 "cargo:cargo-nextest" = "0.9.126"
 "cargo:cargo-shear" = "latest"
@@ -13,6 +13,7 @@ python = "3.14.3"
 ast-grep = "0.42.0"
 "cargo:cargo-edit" = "0.13.9"
 "cargo:cargo-mutants" = "27.0.0"
+"cargo:flutter_rust_bridge_codegen" = "2.12.0"
 
 [tasks.codegen]
 sources = ['protobufs/*.proto', 'protobufs/**/*.proto']

protobufs/client/auth.proto

@@ -10,8 +10,8 @@ message AuthChallengeRequest {
 }
 
 message AuthChallenge {
-  bytes pubkey = 1;
-  int32 nonce = 2;
+  uint64 timestamp_nanos = 1;
+  bytes random = 2;
 }
 
 message AuthChallengeSolution {

protobufs/user_agent/auth.proto

@@ -2,21 +2,14 @@ syntax = "proto3";
 
 package arbiter.user_agent.auth;
 
-enum KeyType {
-  KEY_TYPE_UNSPECIFIED = 0;
-  KEY_TYPE_ED25519 = 1;
-  KEY_TYPE_ECDSA_SECP256K1 = 2;
-  KEY_TYPE_RSA = 3;
-}
-
 message AuthChallengeRequest {
   bytes pubkey = 1;
   optional string bootstrap_token = 2;
-  KeyType key_type = 3;
 }
 
 message AuthChallenge {
-  int32 nonce = 1;
+  uint64 timestamp_nanos = 1;
+  bytes random = 2;
 }
 
 message AuthChallengeSolution {

server/Cargo.toml

@@ -4,47 +4,170 @@ members = [
 ]
 resolver = "3"
 
-[workspace.lints.clippy]
-disallowed-methods = "deny"
-
 
 [workspace.dependencies]
-tonic = { version = "0.14.5", features = [
-    "deflate",
-    "gzip",
-    "tls-connect-info",
-    "zstd",
-] }
-tracing = "0.1.44"
-tokio = { version = "1.50.0", features = ["full"] }
-ed25519-dalek = { version = "3.0.0-pre.6", features = ["rand_core"] }
-chrono = { version = "0.4.44", features = ["serde"] }
-rand = "0.10.0"
-rustls = { version = "0.23.37", features = ["aws-lc-rs", "logging", "prefer-post-quantum", "std"], default-features = false }
-smlang = "0.8.0"
-thiserror = "2.0.18"
+alloy = "2.0.0"
 async-trait = "0.1.89"
-futures = "0.3.32"
-tokio-stream = { version = "0.1.18", features = ["full"] }
-kameo = "0.19.2"
-prost-types = { version = "0.14.3", features = ["chrono"] }
-x25519-dalek = { version = "2.0.1", features = ["getrandom"] }
-rstest = "0.26.1"
-rustls-pki-types = "1.14.0"
-alloy = "1.7.3"
-rcgen = { version = "0.14.7", features = [
-    "aws_lc_rs",
-    "pem",
-    "x509-parser",
-    "zeroize",
-], default-features = false }
-k256 = { version = "0.13.4", features = ["ecdsa", "pkcs8"] }
-rsa = { version = "0.9", features = ["sha2"] }
-sha2 = "0.10"
-spki = "0.7"
-prost = "0.14.3"
-miette = { version = "7.6.0", features = ["fancy", "serde"] }
-mutants = "0.0.4"
-ml-dsa = { version = "0.1.0-rc.8", features = ["zeroize"] }
 base64 = "0.22.1"
-hmac = "0.12.1"
+chrono = { version = "0.4.44", features = ["serde"] }
+ed25519-dalek = { version = "3.0.0-pre.6", features = ["rand_core"] }
+futures = "0.3.32"
+k256 = { version = "0.13.4", features = ["ecdsa", "pkcs8"] }
+kameo = {git = "https://github.com/hdbg/kameo.git", rev = "805b417"}
+kameo_actors = {git = "https://github.com/hdbg/kameo.git", rev = "805b417"}
+hmac = "0.13.0"
+miette = { version = "7.6.0", features = ["fancy", "serde"] }
+ml-dsa = { version = "0.1.0-rc.8", features = ["zeroize"] }
+mutants = "0.0.4"
+prost = "0.14.3"
+prost-types = { version = "0.14.3", features = ["chrono"] }
+rand = "0.10.1"
+rcgen = { version = "0.14.7", features = [ "aws_lc_rs",  "pem", "x509-parser", "zeroize" ], default-features = false }
+rsa = { version = "0.9", features = ["sha2"] }
+rstest = "0.26.1"
+rustls = { version = "0.23.38", features = ["aws-lc-rs", "logging", "prefer-post-quantum", "std"], default-features = false }
+rustls-pki-types = "1.14.0"
+sha2 = "0.11"
+smlang = "0.8.0"
+spki = "0.8"
+thiserror = "2.0.18"
+tokio = { version = "1.52.1", features = ["full"] }
+tokio-stream = { version = "0.1.18", features = ["full"] }
+tonic = { version = "0.14.5", features = [ "deflate", "gzip", "tls-connect-info", "zstd" ] }
+tracing = "0.1.44"
+x25519-dalek = { version = "2.0.1", features = ["getrandom"] }
+
+[workspace.lints.rust]
+missing_unsafe_on_extern = "deny"
+unsafe_attr_outside_unsafe = "deny"
+unsafe_op_in_unsafe_fn = "deny"
+unstable_features = "deny"
+
+deprecated_safe_2024 = "warn"
+ffi_unwind_calls = "warn"
+linker_messages = "warn"
+
+elided_lifetimes_in_paths = "warn"
+explicit_outlives_requirements = "warn"
+impl-trait-overcaptures = "warn"
+impl-trait-redundant-captures = "warn"
+redundant_lifetimes = "warn"
+single_use_lifetimes = "warn"
+unused_lifetimes = "warn"
+
+macro_use_extern_crate = "warn"
+redundant_imports = "warn"
+unused_import_braces = "warn"
+unused_macro_rules = "warn"
+unused_qualifications = "warn"
+
+unit_bindings = "warn"
+
+# missing_docs = "warn" # ENABLE BY THE FIRST MAJOR VERSION!!
+unnameable_types = "warn"
+
+[workspace.lints.clippy]
+derive_partial_eq_without_eq = "allow" 
+future_not_send = "allow"
+inconsistent_struct_constructor = "allow"
+inline_always = "allow"
+missing_errors_doc = "allow"
+missing_fields_in_debug = "allow"
+missing_panics_doc = "allow"
+must_use_candidate = "allow"
+needless_pass_by_ref_mut = "allow"
+pub_underscore_fields = "allow"
+redundant_pub_crate = "allow" 
+uninhabited_references = "allow" # safe with unsafe_code = "forbid" and standard uninhabited pattern (match *self {})
+
+# restriction lints
+alloc_instead_of_core = "warn"
+allow_attributes_without_reason = "warn"
+as_conversions = "warn"
+assertions_on_result_states = "warn"
+cfg_not_test = "warn"
+clone_on_ref_ptr = "warn"
+cognitive_complexity = "warn"
+create_dir = "warn"
+dbg_macro = "warn"
+decimal_literal_representation = "warn"
+default_union_representation = "warn"
+deref_by_slicing = "warn"
+disallowed_script_idents = "warn"
+doc_include_without_cfg = "warn"
+empty_drop = "warn"
+empty_enum_variants_with_brackets = "warn"
+empty_structs_with_brackets = "warn"
+exit = "warn"
+filetype_is_file = "warn"
+float_arithmetic = "warn"
+float_cmp_const = "warn"
+fn_to_numeric_cast_any = "warn"
+get_unwrap = "warn"
+if_then_some_else_none = "warn"
+indexing_slicing = "warn"
+infinite_loop = "warn"
+inline_asm_x86_att_syntax = "warn"
+inline_asm_x86_intel_syntax = "warn"
+integer_division = "warn"
+large_include_file = "warn"
+lossy_float_literal = "warn"
+map_with_unused_argument_over_ranges = "warn"
+mem_forget = "warn"
+missing_assert_message = "warn"
+mixed_read_write_in_expression = "warn"
+modulo_arithmetic = "warn"
+multiple_unsafe_ops_per_block = "warn"
+mutex_atomic = "warn"
+mutex_integer = "warn"
+needless_raw_strings = "warn"
+non_ascii_literal = "warn"
+non_zero_suggestions = "warn"
+pathbuf_init_then_push = "warn"
+pointer_format = "warn"
+precedence_bits = "warn"
+pub_without_shorthand = "warn"
+rc_buffer = "warn"
+rc_mutex = "warn"
+redundant_test_prefix = "warn"
+redundant_type_annotations = "warn"
+ref_patterns = "warn"
+renamed_function_params = "warn"
+rest_pat_in_fully_bound_structs = "warn"
+return_and_then = "warn"
+semicolon_inside_block = "warn"
+str_to_string = "warn"
+string_add = "warn"
+string_lit_chars_any = "warn"
+string_slice = "warn"
+suspicious_xor_used_as_pow = "warn"
+try_err = "warn"
+undocumented_unsafe_blocks = "warn"
+uninlined_format_args = "warn"
+unnecessary_safety_comment = "warn"
+unnecessary_safety_doc = "warn"
+unnecessary_self_imports = "warn"
+unneeded_field_pattern = "warn"
+unused_result_ok = "warn"
+verbose_file_reads = "warn"
+
+# cargo lints
+negative_feature_names = "warn"
+redundant_feature_names = "warn"
+wildcard_dependencies = "warn"
+
+# ENABLE BY THE FIRST MAJOR VERSION!!
+# todo = "warn"
+# unimplemented = "warn"
+# panic = "warn"
+# panic_in_result_fn = "warn"
+# 
+# cargo_common_metadata = "warn"
+# multiple_crate_versions = "warn" # a controversial option since it's really difficult to maintain
+
+disallowed_methods = "deny"
+
+nursery = { level = "warn", priority = -1 }
+pedantic = { level = "warn", priority = -1 }
+
+type_repetition_in_bounds = "allow"   # sometimes, it's better for readability this way

server/clippy.toml

@@ -7,3 +7,22 @@ disallowed-methods = [
     { path = "rsa::traits::Decryptor::decrypt", reason = "RSA decryption is forbidden (RUSTSEC-2023-0071 Marvin Attack). This blocks decrypt() on rsa::{pkcs1v15,oaep}::DecryptingKey." },
     { path = "rsa::traits::RandomizedDecryptor::decrypt_with_rng", reason = "RSA decryption is forbidden (RUSTSEC-2023-0071 Marvin Attack). This blocks decrypt_with_rng() on rsa::{pkcs1v15,oaep}::DecryptingKey." },
 ]
+
+allow-indexing-slicing-in-tests = true
+allow-panic-in-tests = true
+check-inconsistent-struct-field-initializers = true
+suppress-restriction-lint-in-const = true
+allow-renamed-params-for = [
+    "core::convert::From",
+    "core::convert::TryFrom",
+    "core::str::FromStr",
+    "kameo::actor::Actor",
+]
+
+module-items-ordered-within-groupings = ["UPPER_SNAKE_CASE"]
+source-item-ordering = ["enum"]
+trait-assoc-item-kinds-order = [
+    "const",
+    "type",
+    "fn",
+] # community tested standard

server/crates/arbiter-client/Cargo.toml

@@ -21,6 +21,7 @@ tokio.workspace = true
 tokio-stream.workspace = true
 thiserror.workspace = true
 http = "1.4.0"
-rustls-webpki = { version = "0.103.10", features = ["aws-lc-rs"] }
+rustls-webpki = { version = "0.103.12", features = ["aws-lc-rs"] }
 async-trait.workspace = true
 rand.workspace = true
+chrono.workspace = true

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

@@ -1,4 +1,8 @@
-use arbiter_crypto::authn::{CLIENT_CONTEXT, SigningKey, format_challenge};
+use crate::{
+    storage::StorageError,
+    transport::{ClientTransport, next_request_id},
+};
+use arbiter_crypto::authn::{self, CLIENT_CONTEXT, SigningKey};
 use arbiter_proto::{
     ClientMetadata,
     proto::{
@@ -16,27 +20,25 @@ use arbiter_proto::{
     },
 };
 
-use crate::{
-    storage::StorageError,
-    transport::{ClientTransport, next_request_id},
-};
+use chrono::DateTime;
 
 #[derive(Debug, thiserror::Error)]
 pub enum AuthError {
-    #[error("Auth challenge was not returned by server")]
-    MissingAuthChallenge,
-
+    #[error("Server sent invalid auth challenge")]
+    InvalidChallenge,
     #[error("Client approval denied by User Agent")]
     ApprovalDenied,
+    #[error("Auth challenge was not returned by server")]
+    MissingAuthChallenge,
 
     #[error("No User Agents online to approve client")]
     NoUserAgentsOnline,
 
-    #[error("Unexpected auth response payload")]
-    UnexpectedAuthResponse,
-
     #[error("Signing key storage error")]
     Storage(#[from] StorageError),
+
+    #[error("Unexpected auth response payload")]
+    UnexpectedAuthResponse,
 }
 
 fn map_auth_result(code: i32) -> AuthError {
@@ -55,7 +57,7 @@ async fn send_auth_challenge_request(
     transport: &mut ClientTransport,
     metadata: ClientMetadata,
     key: &SigningKey,
-) -> std::result::Result<(), AuthError> {
+) -> Result<(), AuthError> {
     transport
         .send(ClientRequest {
             request_id: next_request_id(),
@@ -76,7 +78,7 @@ async fn send_auth_challenge_request(
 
 async fn receive_auth_challenge(
     transport: &mut ClientTransport,
-) -> std::result::Result<AuthChallenge, AuthError> {
+) -> Result<AuthChallenge, AuthError> {
     let response = transport
         .recv()
         .await
@@ -97,8 +99,16 @@ async fn send_auth_challenge_solution(
     transport: &mut ClientTransport,
     key: &SigningKey,
     challenge: AuthChallenge,
-) -> std::result::Result<(), AuthError> {
-    let challenge_payload = format_challenge(challenge.nonce, &challenge.pubkey);
+) -> Result<(), AuthError> {
+    let timestamp = DateTime::from_timestamp_nanos(challenge.timestamp_nanos as i64);
+    let challenge = authn::AuthChallenge {
+        nonce: *challenge
+            .random
+            .as_array()
+            .ok_or(AuthError::InvalidChallenge)?,
+        timestamp,
+    };
+    let challenge_payload: Vec<u8> = challenge.format();
     let signature = key
         .sign_message(&challenge_payload, CLIENT_CONTEXT)
         .map_err(|_| AuthError::UnexpectedAuthResponse)?
@@ -117,9 +127,7 @@ async fn send_auth_challenge_solution(
         .map_err(|_| AuthError::UnexpectedAuthResponse)
 }
 
-async fn receive_auth_confirmation(
-    transport: &mut ClientTransport,
-) -> std::result::Result<(), AuthError> {
+async fn receive_auth_confirmation(transport: &mut ClientTransport) -> Result<(), AuthError> {
     let response = transport
         .recv()
         .await
@@ -140,11 +148,11 @@ async fn receive_auth_confirmation(
     }
 }
 
-pub(crate) async fn authenticate(
+pub async fn authenticate(
     transport: &mut ClientTransport,
     metadata: ClientMetadata,
     key: &SigningKey,
-) -> std::result::Result<(), AuthError> {
+) -> Result<(), AuthError> {
     send_auth_challenge_request(transport, metadata, key).await?;
     let challenge = receive_auth_challenge(transport).await?;
     send_auth_challenge_solution(transport, key, challenge).await?;

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

@@ -1,8 +1,8 @@
-use std::io::{self, Write};
-
 use arbiter_client::ArbiterClient;
 use arbiter_proto::{ClientMetadata, url::ArbiterUrl};
 
+use std::io::{self, Write};
+
 #[tokio::main]
 async fn main() {
     println!("Testing connection to Arbiter server...");
@@ -29,16 +29,16 @@ async fn main() {
         }
     };
 
-    println!("{:#?}", url);
+    println!("{url:#?}");
 
     let metadata = ClientMetadata {
-        name: "arbiter-client test_connect".to_string(),
-        description: Some("Manual connection smoke test".to_string()),
-        version: Some(env!("CARGO_PKG_VERSION").to_string()),
+        name: "arbiter-client test_connect".to_owned(),
+        description: Some("Manual connection smoke test".to_owned()),
+        version: Some(env!("CARGO_PKG_VERSION").to_owned()),
     };
 
     match ArbiterClient::connect(url, metadata).await {
         Ok(_) => println!("Connected and authenticated successfully."),
-        Err(err) => eprintln!("Failed to connect: {:#?}", err),
+        Err(err) => eprintln!("Failed to connect: {err:#?}"),
     }
 }

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

@@ -1,50 +1,55 @@
-use arbiter_crypto::authn::SigningKey;
-use arbiter_proto::{
-    ClientMetadata, proto::arbiter_service_client::ArbiterServiceClient, url::ArbiterUrl,
-};
-use std::sync::Arc;
-use tokio::sync::{Mutex, mpsc};
-use tokio_stream::wrappers::ReceiverStream;
-use tonic::transport::ClientTlsConfig;
-
+#[cfg(feature = "evm")]
+use crate::wallets::evm::ArbiterEvmWallet;
 use crate::{
     StorageError,
     auth::{AuthError, authenticate},
     storage::{FileSigningKeyStorage, SigningKeyStorage},
     transport::{BUFFER_LENGTH, ClientTransport},
 };
+use arbiter_crypto::authn::SigningKey;
+use arbiter_proto::{
+    ClientMetadata, proto::arbiter_service_client::ArbiterServiceClient, url::ArbiterUrl,
+};
 
-#[cfg(feature = "evm")]
-use crate::wallets::evm::ArbiterEvmWallet;
+use std::sync::Arc;
+use tokio::sync::{Mutex, mpsc};
+use tokio_stream::wrappers::ReceiverStream;
+use tonic::transport::ClientTlsConfig;
 
 #[derive(Debug, thiserror::Error)]
-pub enum Error {
-    #[error("gRPC error")]
-    Grpc(#[from] tonic::Status),
+pub enum ArbiterClientError {
+    #[error("Authentication error")]
+    Authentication(#[from] AuthError),
 
     #[error("Could not establish connection")]
     Connection(#[from] tonic::transport::Error),
 
-    #[error("Invalid server URI")]
-    InvalidUri(#[from] http::uri::InvalidUri),
+    #[error("gRPC error")]
+    Grpc(#[from] tonic::Status),
 
     #[error("Invalid CA certificate")]
     InvalidCaCert(#[from] webpki::Error),
 
-    #[error("Authentication error")]
-    Authentication(#[from] AuthError),
+    #[error("Invalid server URI")]
+    InvalidUri(#[from] http::uri::InvalidUri),
 
     #[error("Storage error")]
     Storage(#[from] StorageError),
 }
 
 pub struct ArbiterClient {
-    #[allow(dead_code)]
+    #[expect(
+        dead_code,
+        reason = "transport will be used in future methods for sending requests and receiving responses"
+    )]
     transport: Arc<Mutex<ClientTransport>>,
 }
 
 impl ArbiterClient {
-    pub async fn connect(url: ArbiterUrl, metadata: ClientMetadata) -> Result<Self, Error> {
+    pub async fn connect(
+        url: ArbiterUrl,
+        metadata: ClientMetadata,
+    ) -> Result<Self, ArbiterClientError> {
         let storage = FileSigningKeyStorage::from_default_location()?;
         Self::connect_with_storage(url, metadata, &storage).await
     }
@@ -53,7 +58,7 @@ impl ArbiterClient {
         url: ArbiterUrl,
         metadata: ClientMetadata,
         storage: &S,
-    ) -> Result<Self, Error> {
+    ) -> Result<Self, ArbiterClientError> {
         let key = storage.load_or_create()?;
         Self::connect_with_key(url, metadata, key).await
     }
@@ -62,7 +67,7 @@ impl ArbiterClient {
         url: ArbiterUrl,
         metadata: ClientMetadata,
         key: SigningKey,
-    ) -> Result<Self, Error> {
+    ) -> Result<Self, ArbiterClientError> {
         let anchor = webpki::anchor_from_trusted_cert(&url.ca_cert)?.to_owned();
         let tls = ClientTlsConfig::new().trust_anchor(anchor);
 
@@ -89,7 +94,8 @@ impl ArbiterClient {
     }
 
     #[cfg(feature = "evm")]
-    pub async fn evm_wallets(&self) -> Result<Vec<ArbiterEvmWallet>, Error> {
+    #[expect(clippy::unused_async, reason = "false positive")]
+    pub async fn evm_wallets(&self) -> Result<Vec<ArbiterEvmWallet>, ArbiterClientError> {
         todo!("fetch EVM wallet list from server")
     }
 }

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

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

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

@@ -1,18 +1,19 @@
 use arbiter_crypto::authn::SigningKey;
 use arbiter_proto::home_path;
+
 use std::path::{Path, PathBuf};
 
 #[derive(Debug, thiserror::Error)]
 pub enum StorageError {
-    #[error("I/O error")]
-    Io(#[from] std::io::Error),
-
     #[error("Invalid signing key length in storage: expected {expected} bytes, got {actual} bytes")]
     InvalidKeyLength { expected: usize, actual: usize },
+
+    #[error("I/O error")]
+    Io(#[from] std::io::Error),
 }
 
 pub trait SigningKeyStorage {
-    fn load_or_create(&self) -> std::result::Result<SigningKey, StorageError>;
+    fn load_or_create(&self) -> Result<SigningKey, StorageError>;
 }
 
 #[derive(Debug, Clone)]
@@ -27,11 +28,11 @@ impl FileSigningKeyStorage {
         Self { path: path.into() }
     }
 
-    pub fn from_default_location() -> std::result::Result<Self, StorageError> {
+    pub fn from_default_location() -> Result<Self, StorageError> {
         Ok(Self::new(home_path()?.join(Self::DEFAULT_FILE_NAME)))
     }
 
-    fn read_key(path: &Path) -> std::result::Result<SigningKey, StorageError> {
+    fn read_key(path: &Path) -> Result<SigningKey, StorageError> {
         let bytes = std::fs::read(path)?;
         let raw: [u8; 32] =
             bytes
@@ -45,7 +46,7 @@ impl FileSigningKeyStorage {
 }
 
 impl SigningKeyStorage for FileSigningKeyStorage {
-    fn load_or_create(&self) -> std::result::Result<SigningKey, StorageError> {
+    fn load_or_create(&self) -> Result<SigningKey, StorageError> {
         if let Some(parent) = self.path.parent() {
             std::fs::create_dir_all(parent)?;
         }
@@ -125,7 +126,7 @@ mod tests {
                 assert_eq!(expected, 32);
                 assert_eq!(actual, 31);
             }
-            other => panic!("unexpected error: {other:?}"),
+            other @ StorageError::Io(_) => panic!("unexpected error: {other:?}"),
         }
 
         std::fs::remove_file(path).expect("temp key file should be removable");

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

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

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

@@ -1,13 +1,4 @@
-use alloy::{
-    consensus::SignableTransaction,
-    network::TxSigner,
-    primitives::{Address, B256, ChainId, Signature},
-    signers::{Error, Result, Signer},
-};
-use async_trait::async_trait;
-use std::sync::Arc;
-use tokio::sync::Mutex;
-
+use crate::transport::{ClientTransport, next_request_id};
 use arbiter_proto::proto::{
     client::{
         ClientRequest,
@@ -25,7 +16,15 @@ use arbiter_proto::proto::{
     shared::evm::TransactionEvalError,
 };
 
-use crate::transport::{ClientTransport, next_request_id};
+use alloy::{
+    consensus::SignableTransaction,
+    network::TxSigner,
+    primitives::{Address, B256, ChainId, Signature},
+    signers::{Error, Result, Signer},
+};
+use async_trait::async_trait;
+use std::sync::Arc;
+use tokio::sync::Mutex;
 
 /// A typed error payload returned by [`ArbiterEvmWallet`] transaction signing.
 ///
@@ -59,7 +58,11 @@ pub struct ArbiterEvmWallet {
 }
 
 impl ArbiterEvmWallet {
-    pub(crate) fn new(transport: Arc<Mutex<ClientTransport>>, address: Address) -> Self {
+    #[expect(
+        dead_code,
+        reason = "new will be used in future methods for creating wallets with different parameters"
+    )]
+    pub(crate) const fn new(transport: Arc<Mutex<ClientTransport>>, address: Address) -> Self {
         Self {
             transport,
             address,
@@ -67,11 +70,12 @@ impl ArbiterEvmWallet {
         }
     }
 
-    pub fn address(&self) -> Address {
+    pub const fn address(&self) -> Address {
         self.address
     }
 
-    pub fn with_chain_id(mut self, chain_id: ChainId) -> Self {
+    #[must_use]
+    pub const fn with_chain_id(mut self, chain_id: ChainId) -> Self {
         self.chain_id = Some(chain_id);
         self
     }
@@ -146,6 +150,7 @@ impl TxSigner<Signature> for ArbiterEvmWallet {
             .recv()
             .await
             .map_err(|_| Error::other("failed to receive evm sign transaction response"))?;
+        drop(transport);
 
         if response.request_id != Some(request_id) {
             return Err(Error::other(

server/crates/arbiter-crypto/Cargo.toml

@@ -6,16 +6,17 @@ edition = "2024"
 [dependencies]
 ml-dsa = {workspace = true, optional = true }
 rand = {workspace = true, optional = true}
-base64 = {workspace = true, optional = true }
 memsafe = {version = "0.4.0", optional = true}
 hmac.workspace = true
 alloy.workspace = true
+x-wing = { version = "0.1.0-rc.0", features = ["zeroize"] }
 chrono.workspace = true
+thiserror.workspace = true
 
 [lints]
 workspace = true
 
 [features]
 default = ["authn", "safecell"]
-authn = ["dep:ml-dsa", "dep:rand", "dep:base64"]
+authn = ["dep:ml-dsa", "dep:rand"]
 safecell = ["dep:memsafe"]

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

@@ -1,16 +1,65 @@
-use base64::{Engine as _, prelude::BASE64_STANDARD};
+use chrono::{DateTime, Utc};
 use hmac::digest::Digest;
 use ml_dsa::{
     EncodedVerifyingKey, Error, KeyGen, MlDsa87, Seed, Signature as MlDsaSignature,
     SigningKey as MlDsaSigningKey, VerifyingKey as MlDsaVerifyingKey, signature::Keypair as _,
 };
+use rand::RngExt;
 
 pub static CLIENT_CONTEXT: &[u8] = b"arbiter_client";
 pub static USERAGENT_CONTEXT: &[u8] = b"arbiter_user_agent";
 
-pub fn format_challenge(nonce: i32, pubkey: &[u8]) -> Vec<u8> {
-    let concat_form = format!("{}:{}", nonce, BASE64_STANDARD.encode(pubkey));
-    concat_form.into_bytes()
+const NONCE_SIZE: usize = 32;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, thiserror::Error)]
+#[error("invalid length: expected {expected} bytes, got {actual} bytes")]
+pub struct InvalidLength {
+    pub expected: usize,
+    pub actual: usize,
+}
+
+#[derive(Debug, Clone)]
+pub struct AuthChallenge {
+    pub nonce: [u8; NONCE_SIZE],
+    pub timestamp: DateTime<Utc>,
+}
+
+impl AuthChallenge {
+    pub fn generate(rng: &mut impl rand::CryptoRng) -> Self {
+        let timestamp = Utc::now();
+        let nonce = {
+            let mut array = [0; NONCE_SIZE];
+            rng.fill(&mut array);
+            array
+        };
+
+        Self { nonce, timestamp }
+    }
+
+    pub fn format(&self) -> Vec<u8> {
+        {
+            let mut buffer = Vec::from(self.nonce);
+
+            let stamp = self
+                .timestamp
+                .timestamp_nanos_opt()
+                .expect("We would be long dead by the time this triggers :)");
+            buffer.extend_from_slice(stamp.to_be_bytes().as_slice());
+
+            buffer
+        }
+    }
+
+    pub fn from_parts(nonce: &[u8], timestamp: i64) -> Result<Self, InvalidLength> {
+        let random_nonce = nonce.as_array().ok_or(InvalidLength {
+            expected: NONCE_SIZE,
+            actual: nonce.len(),
+        })?;
+        Ok(Self {
+            nonce: *random_nonce,
+            timestamp: DateTime::from_timestamp_nanos(timestamp),
+        })
+    }
 }
 
 pub type KeyParams = MlDsa87;
@@ -35,12 +84,11 @@ impl PublicKey {
         self.0.encode().0.to_vec()
     }
 
-    pub fn verify(&self, nonce: i32, context: &[u8], signature: &Signature) -> bool {
-        self.0.verify_with_context(
-            &format_challenge(nonce, &self.to_bytes()),
-            context,
-            &signature.0,
-        )
+    #[must_use]
+    pub fn verify(&self, challenge: &AuthChallenge, context: &[u8], signature: &Signature) -> bool {
+        let challenge = challenge.format();
+        self.0
+            .verify_with_context(&challenge, context, &signature.0)
     }
 }
 
@@ -74,11 +122,14 @@ impl SigningKey {
             .map(Into::into)
     }
 
-    pub fn sign_challenge(&self, nonce: i32, context: &[u8]) -> Result<Signature, Error> {
-        self.sign_message(
-            &format_challenge(nonce, &self.public_key().to_bytes()),
-            context,
-        )
+    pub fn sign_challenge(
+        &self,
+        challenge: &AuthChallenge,
+        context: &[u8],
+    ) -> Result<Signature, Error> {
+        let challenge = challenge.format();
+
+        self.sign_message(&challenge, context)
     }
 }
 
@@ -139,6 +190,8 @@ impl TryFrom<&'_ [u8]> for Signature {
 mod tests {
     use ml_dsa::{KeyGen, MlDsa87, signature::Keypair as _};
 
+    use crate::authn::AuthChallenge;
+
     use super::{CLIENT_CONTEXT, PublicKey, Signature, SigningKey, USERAGENT_CONTEXT};
 
     #[test]
@@ -168,13 +221,13 @@ mod tests {
     fn challenge_verification_uses_context_and_canonical_key_bytes() {
         let key = SigningKey::generate();
         let public_key = key.public_key();
-        let nonce = 17;
+        let challenge = AuthChallenge::generate(&mut rand::rng());
         let signature = key
-            .sign_challenge(nonce, CLIENT_CONTEXT)
+            .sign_challenge(&challenge, CLIENT_CONTEXT)
             .expect("signature should be created");
 
-        assert!(public_key.verify(nonce, CLIENT_CONTEXT, &signature));
-        assert!(!public_key.verify(nonce, USERAGENT_CONTEXT, &signature));
+        assert!(public_key.verify(&challenge, CLIENT_CONTEXT, &signature));
+        assert!(!public_key.verify(&challenge, USERAGENT_CONTEXT, &signature));
     }
 
     #[test]
@@ -184,10 +237,16 @@ mod tests {
 
         assert_eq!(restored.public_key(), original.public_key());
 
+        let challenge = AuthChallenge::generate(&mut rand::rng());
+
         let signature = restored
-            .sign_challenge(9, CLIENT_CONTEXT)
+            .sign_challenge(&challenge, CLIENT_CONTEXT)
             .expect("signature should be created");
 
-        assert!(restored.public_key().verify(9, CLIENT_CONTEXT, &signature));
+        assert!(
+            restored
+                .public_key()
+                .verify(&challenge, CLIENT_CONTEXT, &signature)
+        );
     }
 }

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

@@ -1,6 +1,7 @@
-pub use hmac::digest::Digest;
 use std::collections::HashSet;
 
+pub use hmac::digest::Digest;
+
 /// Deterministically hash a value by feeding its fields into the hasher in a consistent order.
 #[diagnostic::on_unimplemented(
     note = "for local types consider adding `#[derive(arbiter_macros::Hashable)]` to your `{Self}` type",
@@ -49,7 +50,7 @@ impl<T: Hashable + PartialOrd> Hashable for Vec<T> {
     }
 }
 
-impl<T: Hashable + PartialOrd> Hashable for HashSet<T> {
+impl<T: Hashable + PartialOrd, S: std::hash::BuildHasher> Hashable for HashSet<T, S> {
     fn hash<H: Digest>(&self, hasher: &mut H) {
         let ref_sorted = {
             let mut sorted = self.iter().collect::<Vec<_>>();

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

@@ -3,3 +3,5 @@ pub mod authn;
 pub mod hashing;
 #[cfg(feature = "safecell")]
 pub mod safecell;
+
+pub use x_wing;

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

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

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

@@ -1,10 +1,8 @@
+use crate::utils::{HASHABLE_TRAIT_PATH, HMAC_DIGEST_PATH};
+
 use proc_macro2::{Span, TokenStream, TokenTree};
 use quote::quote;
-use syn::parse_quote;
-use syn::spanned::Spanned;
-use syn::{DataStruct, DeriveInput, Fields, Generics, Index};
-
-use crate::utils::{HASHABLE_TRAIT_PATH, HMAC_DIGEST_PATH};
+use syn::{DataStruct, DeriveInput, Fields, Generics, Index, parse_quote, spanned::Spanned};
 
 pub(crate) fn derive(input: &DeriveInput) -> TokenStream {
     match &input.data {
@@ -20,7 +18,7 @@ pub(crate) fn derive(input: &DeriveInput) -> TokenStream {
     }
 }
 
-fn hashable_struct(input: &DeriveInput, struct_data: &syn::DataStruct) -> TokenStream {
+fn hashable_struct(input: &DeriveInput, struct_data: &DataStruct) -> TokenStream {
     let ident = &input.ident;
     let hashable_trait = HASHABLE_TRAIT_PATH.to_path();
     let hmac_digest = HMAC_DIGEST_PATH.to_path();

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

@@ -1,19 +1,24 @@
-pub struct ToPath(pub &'static str);
+pub(crate) struct ToPath(pub &'static str);
 
 impl ToPath {
-    pub fn to_path(&self) -> syn::Path {
+    pub(crate) fn to_path(&self) -> syn::Path {
         syn::parse_str(self.0).expect("Invalid path")
     }
 }
 
 macro_rules! ensure_path {
-    ($path:path) => {{
+    ($path:path as $name:ident) => {
+        const _: () = {
             #[cfg(test)]
-        #[expect(unused_imports)]
+            #[expect(
+                unused_imports,
+                reason = "Ensures the path is valid and will cause a compile error if not"
+            )]
             use $path as _;
-        ToPath(stringify!($path))
-    }};
+        };
+        pub(crate) const $name: ToPath = ToPath(stringify!($path));
+    };
 }
 
-pub const HASHABLE_TRAIT_PATH: ToPath = ensure_path!(::arbiter_crypto::hashing::Hashable);
-pub const HMAC_DIGEST_PATH: ToPath = ensure_path!(::arbiter_crypto::hashing::Digest);
+ensure_path!(::arbiter_crypto::hashing::Hashable as HASHABLE_TRAIT_PATH);
+ensure_path!(::arbiter_crypto::hashing::Digest as HMAC_DIGEST_PATH);

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

@@ -54,10 +54,9 @@
 //!   as a closed outbound channel.
 //! - [`Bi::recv`] returns `None` when the underlying transport closes.
 //! - Message translation is intentionally out of scope for this module.
-
-use std::marker::PhantomData;
-
 use async_trait::async_trait;
+use kameo::{error::Infallible, prelude::*};
+use std::marker::PhantomData;
 
 /// Errors returned by transport adapters implementing [`Bi`].
 #[derive(thiserror::Error, Debug)]
@@ -106,6 +105,36 @@ pub trait Receiver<Inbound>: Send + Sync {
 /// any built-in correlation mechanism between inbound and outbound items.
 pub trait Bi<Inbound, Outbound>: Sender<Outbound> + Receiver<Inbound> + Send + Sync {}
 
+#[async_trait]
+impl<T, Outbound> Sender<Outbound> for &mut T
+where
+    T: Sender<Outbound> + ?Sized,
+    Outbound: Send + 'static,
+{
+    async fn send(&mut self, item: Outbound) -> Result<(), Error> {
+        (**self).send(item).await
+    }
+}
+
+#[async_trait]
+impl<T, Inbound> Receiver<Inbound> for &mut T
+where
+    T: Receiver<Inbound> + ?Sized,
+    Inbound: Send + 'static,
+{
+    async fn recv(&mut self) -> Option<Inbound> {
+        (**self).recv().await
+    }
+}
+
+impl<T, Inbound, Outbound> Bi<Inbound, Outbound> for &mut T
+where
+    T: Bi<Inbound, Outbound> + ?Sized,
+    Inbound: Send + 'static,
+    Outbound: Send + 'static,
+{
+}
+
 pub trait SplittableBi<Inbound, Outbound>: Bi<Inbound, Outbound> {
     type Sender: Sender<Outbound>;
     type Receiver: Receiver<Inbound>;
@@ -161,3 +190,29 @@ where
 }
 
 pub mod grpc;
+
+#[derive(thiserror::Error, Debug)]
+pub enum ForwardError<I> {
+    #[error("Transport error: {0}")]
+    Transport(#[from] Error),
+    #[error("Actor delivery error: {0}")]
+    Actor(SendError<I>),
+}
+
+pub async fn forward_to_actor<Transport, Inbound, Outbound, Handler>(
+    transport: &mut Transport,
+    actor: &ActorRef<Handler>,
+) -> Result<(), ForwardError<Inbound>>
+where
+    Transport: Bi<Inbound, <Outbound as Reply>::Ok>,
+    Handler: Actor + Message<Inbound, Reply = Outbound>,
+    Inbound: Send + 'static,
+    Outbound: Send + 'static + Reply<Error = Infallible>, // `Infallible` to enforce contract that `Outbound` carries handler-level error
+{
+    while let Some(request) = transport.recv().await {
+        let resp = actor.ask(request).await.map_err(ForwardError::Actor)?;
+        transport.send(resp).await?
+    }
+
+    Err(Error::ChannelClosed.into())
+}

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

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

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

@@ -1,7 +1,6 @@
-use std::fmt::Display;
-
 use base64::{Engine as _, prelude::BASE64_URL_SAFE};
 use rustls_pki_types::CertificateDer;
+use std::fmt::Display;
 
 const ARBITER_URL_SCHEME: &str = "arbiter";
 const CERT_QUERY_KEY: &str = "cert";
@@ -105,7 +104,7 @@ mod tests {
 
     #[rstest]
 
-    fn test_parsing_correctness(
+    fn parsing_correctness(
         #[values("127.0.0.1", "localhost", "192.168.1.1", "some.domain.com")] host: &str,
 
         #[values(None, Some("token123".to_string()))] bootstrap_token: Option<String>,

server/crates/arbiter-server/Cargo.toml

@@ -59,9 +59,10 @@ ml-dsa.workspace = true
 ed25519-dalek.workspace = true
 x25519-dalek.workspace = true
 k256.workspace = true
+kameo_actors.workspace = true
 
 [dev-dependencies]
-insta = "1.46.3"
+insta = "1.47.2"
 proptest = "1.11.0"
 rstest.workspace = true
 test-log = { version = "0.2", default-features = false, features = ["trace"] }

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

@@ -45,13 +45,11 @@ insert into arbiter_settings (id) values (1) on conflict do nothing;
 
 create table if not exists useragent_client (
     id integer not null primary key,
-    nonce integer not null default(1), -- used for auth challenge
     public_key blob not null,
-    key_type integer not null default(1),
     created_at integer not null default(unixepoch ('now')),
     updated_at integer not null default(unixepoch ('now'))
 ) STRICT;
-create unique index if not exists uniq_useragent_client_public_key on useragent_client (public_key, key_type);
+create unique index if not exists uniq_useragent_client_public_key on useragent_client (public_key);
 
 create table if not exists client_metadata (
     id integer not null primary key,
@@ -73,7 +71,6 @@ create unique index if not exists uniq_metadata_binding_client on client_metadat
 
 create table if not exists program_client (
     id integer not null primary key,
-    nonce integer not null default(1), -- used for auth challenge
     public_key blob not null,
     metadata_id integer not null references client_metadata (id) on delete cascade,
     created_at integer not null default(unixepoch ('now')),

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

@@ -1,20 +1,20 @@
+use crate::db::{self, DatabasePool, schema};
 use arbiter_proto::{BOOTSTRAP_PATH, home_path};
+
 use diesel::QueryDsl;
 use diesel_async::RunQueryDsl;
 use kameo::{Actor, messages};
-
 use rand::{RngExt, distr::Alphanumeric, make_rng, rngs::StdRng};
 use subtle::ConstantTimeEq as _;
 use thiserror::Error;
 
-use crate::db::{self, DatabasePool, schema};
 const TOKEN_LENGTH: usize = 64;
 
 pub async fn generate_token() -> Result<String, std::io::Error> {
     let rng: StdRng = make_rng();
 
-    let token: String = rng.sample_iter(Alphanumeric).take(TOKEN_LENGTH).fold(
-        Default::default(),
+    let token = rng.sample_iter(Alphanumeric).take(TOKEN_LENGTH).fold(
+        String::default(),
         |mut accum, char| {
             accum += char.to_string().as_str();
             accum
@@ -31,11 +31,11 @@ pub enum Error {
     #[error("Database error: {0}")]
     Database(#[from] db::PoolError),
 
-    #[error("Database query error: {0}")]
-    Query(#[from] diesel::result::Error),
-
     #[error("I/O error: {0}")]
     Io(#[from] std::io::Error),
+
+    #[error("Database query error: {0}")]
+    Query(#[from] diesel::result::Error),
 }
 
 #[derive(Actor)]
@@ -69,16 +69,13 @@ impl Bootstrapper {
 impl Bootstrapper {
     #[message]
     pub fn is_correct_token(&self, token: String) -> bool {
-        match &self.token {
-            Some(expected) => {
+        self.token.as_ref().is_some_and(|expected| {
             let expected_bytes = expected.as_bytes();
             let token_bytes = token.as_bytes();
 
             let choice = expected_bytes.ct_eq(token_bytes);
             bool::from(choice)
-            }
-            None => false,
-        }
+        })
     }
 
     #[message]

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

@@ -1,13 +1,5 @@
-use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
-use diesel::{
-    ExpressionMethods, OptionalExtension as _, QueryDsl, SelectableHelper as _, dsl::insert_into,
-};
-use diesel_async::RunQueryDsl;
-use kameo::{Actor, actor::ActorRef, messages};
-use rand::{SeedableRng, rng, rngs::StdRng};
-
 use crate::{
-    actors::keyholder::{CreateNew, Decrypt, KeyHolder},
+    actors::vault::{CreateNew, Decrypt, Vault},
     crypto::integrity,
     db::{
         DatabaseError, DatabasePool,
@@ -24,6 +16,16 @@ use crate::{
 };
 use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 
+use alloy::{
+    consensus::TxEip1559, network::TxSignerSync as _, primitives::Address, signers::Signature,
+};
+use diesel::{
+    ExpressionMethods, OptionalExtension as _, QueryDsl, SelectableHelper as _, dsl::insert_into,
+};
+use diesel_async::RunQueryDsl;
+use kameo::{Actor, actor::ActorRef, messages};
+use rand::{SeedableRng, rng, rngs::StdRng};
+
 pub use crate::evm::safe_signer;
 
 #[derive(Debug, thiserror::Error)]
@@ -34,11 +36,11 @@ pub enum SignTransactionError {
     #[error("Database error: {0}")]
     Database(#[from] DatabaseError),
 
-    #[error("Keyholder error: {0}")]
-    Keyholder(#[from] crate::actors::keyholder::Error),
+    #[error("Vault error: {0}")]
+    Vault(#[from] crate::actors::vault::Error),
 
-    #[error("Keyholder mailbox error")]
-    KeyholderSend,
+    #[error("Vault mailbox error")]
+    VaultSend,
 
     #[error("Signing error: {0}")]
     Signing(#[from] alloy::signers::Error),
@@ -49,11 +51,11 @@ pub enum SignTransactionError {
 
 #[derive(Debug, thiserror::Error)]
 pub enum Error {
-    #[error("Keyholder error: {0}")]
-    Keyholder(#[from] crate::actors::keyholder::Error),
+    #[error("Vault error: {0}")]
+    Vault(#[from] crate::actors::vault::Error),
 
-    #[error("Keyholder mailbox error")]
-    KeyholderSend,
+    #[error("Vault mailbox error")]
+    VaultSend,
 
     #[error("Database error: {0}")]
     Database(#[from] DatabaseError),
@@ -64,20 +66,20 @@ pub enum Error {
 
 #[derive(Actor)]
 pub struct EvmActor {
-    pub keyholder: ActorRef<KeyHolder>,
+    pub vault: ActorRef<Vault>,
     pub db: DatabasePool,
     pub rng: StdRng,
     pub engine: evm::Engine,
 }
 
 impl EvmActor {
-    pub fn new(keyholder: ActorRef<KeyHolder>, db: DatabasePool) -> Self {
+    pub fn new(vault: ActorRef<Vault>, db: DatabasePool) -> Self {
         // is it safe to seed rng from system once?
         // todo: audit
         let rng = StdRng::from_rng(&mut rng());
-        let engine = evm::Engine::new(db.clone(), keyholder.clone());
+        let engine = evm::Engine::new(db.clone(), vault.clone());
         Self {
-            keyholder,
+            vault,
             db,
             rng,
             engine,
@@ -94,10 +96,10 @@ impl EvmActor {
         let plaintext = key_cell.read_inline(|reader| SafeCell::new(reader.to_vec()));
 
         let aead_id: i32 = self
-            .keyholder
+            .vault
             .ask(CreateNew { plaintext })
             .await
-            .map_err(|_| Error::KeyholderSend)?;
+            .map_err(|_| Error::VaultSend)?;
 
         let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
         let wallet_id = insert_into(schema::evm_wallet::table)
@@ -158,9 +160,10 @@ impl EvmActor {
     }
 
     #[message]
+    #[expect(clippy::unused_async, reason = "reserved for impl")]
     pub async fn useragent_delete_grant(&mut self, _grant_id: i32) -> Result<(), Error> {
         // let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
-        // let keyholder = self.keyholder.clone();
+        // let vault = self.vault.clone();
 
         // diesel_async::AsyncConnection::transaction(&mut conn, |conn| {
         //     Box::pin(async move {
@@ -254,12 +257,12 @@ impl EvmActor {
         drop(conn);
 
         let raw_key: SafeCell<Vec<u8>> = self
-            .keyholder
+            .vault
             .ask(Decrypt {
                 aead_id: wallet.aead_encrypted_id,
             })
             .await
-            .map_err(|_| SignTransactionError::KeyholderSend)?;
+            .map_err(|_| SignTransactionError::VaultSend)?;
 
         let signer = safe_signer::SafeSigner::from_cell(raw_key)?;
 
@@ -267,7 +270,6 @@ impl EvmActor {
             .evaluate_transaction(wallet_access, transaction.clone(), RunKind::Execution)
             .await?;
 
-        use alloy::network::TxSignerSync as _;
         Ok(signer.sign_transaction_sync(&mut transaction)?)
     }
 }

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

@@ -1,16 +1,17 @@
-use std::ops::ControlFlow;
+use crate::{
+    actors::flow_coordinator::ApprovalError,
+    peers::{
+        client::ClientProfile,
+        user_agent::{UserAgentSession, session::BeginNewClientApproval},
+    },
+};
 
 use kameo::{
     Actor, messages,
     prelude::{ActorId, ActorRef, ActorStopReason, Context, WeakActorRef},
     reply::ReplySender,
 };
-
-use crate::actors::{
-    client::ClientProfile,
-    flow_coordinator::ApprovalError,
-    user_agent::{UserAgentSession, session::BeginNewClientApproval},
-};
+use std::ops::ControlFlow;
 
 pub struct Args {
     pub client: ClientProfile,
@@ -41,7 +42,7 @@ impl Actor for ClientApprovalController {
     async fn on_start(
         Args {
             client,
-            mut user_agents,
+            user_agents,
             reply,
         }: Self::Args,
         actor_ref: ActorRef<Self>,
@@ -52,8 +53,9 @@ impl Actor for ClientApprovalController {
             reply: Some(reply),
         };
 
-        for user_agent in user_agents.drain(..) {
+        for user_agent in user_agents {
             actor_ref.link(&user_agent).await;
+
             let _ = user_agent
                 .tell(BeginNewClientApproval {
                     client: client.clone(),
@@ -85,7 +87,7 @@ impl Actor for ClientApprovalController {
 #[messages]
 impl ClientApprovalController {
     #[message(ctx)]
-    pub async fn client_approval_answer(&mut self, approved: bool, ctx: &mut Context<Self, ()>) {
+    pub fn client_approval_answer(&mut self, approved: bool, ctx: &mut Context<Self, ()>) {
         if !approved {
             // Denial wins immediately regardless of other pending responses.
             self.send_reply(Ok(false));

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

@@ -1,4 +1,10 @@
-use std::{collections::HashMap, ops::ControlFlow};
+use crate::{
+    actors::{
+        flow_coordinator::client_connect_approval::ClientApprovalController,
+        useragent_registry::{GetConnected, UserAgentRegistry},
+    },
+    peers::client::{ClientProfile, session::ClientSession},
+};
 
 use kameo::{
     Actor,
@@ -7,20 +13,23 @@ use kameo::{
     prelude::{ActorStopReason, Context, WeakActorRef},
     reply::DelegatedReply,
 };
+use std::{collections::HashMap, ops::ControlFlow};
 use tracing::info;
 
-use crate::actors::{
-    client::{ClientProfile, session::ClientSession},
-    flow_coordinator::client_connect_approval::ClientApprovalController,
-    user_agent::session::UserAgentSession,
-};
-
 pub mod client_connect_approval;
 
-#[derive(Default)]
 pub struct FlowCoordinator {
-    pub user_agents: HashMap<ActorId, ActorRef<UserAgentSession>>,
     pub clients: HashMap<ActorId, ActorRef<ClientSession>>,
+    useragent_registry: ActorRef<UserAgentRegistry>,
+}
+
+impl FlowCoordinator {
+    pub fn new(useragent_registry: ActorRef<UserAgentRegistry>) -> Self {
+        Self {
+            clients: HashMap::default(),
+            useragent_registry,
+        }
+    }
 }
 
 impl Actor for FlowCoordinator {
@@ -38,13 +47,7 @@ impl Actor for FlowCoordinator {
         id: ActorId,
         _: ActorStopReason,
     ) -> Result<ControlFlow<ActorStopReason>, Self::Error> {
-        if self.user_agents.remove(&id).is_some() {
-            info!(
-                ?id,
-                actor = "FlowCoordinator",
-                event = "useragent.disconnected"
-            );
-        } else if self.clients.remove(&id).is_some() {
+        if self.clients.remove(&id).is_some() {
             info!(
                 ?id,
                 actor = "FlowCoordinator",
@@ -69,17 +72,6 @@ pub enum ApprovalError {
 
 #[messages]
 impl FlowCoordinator {
-    #[message(ctx)]
-    pub async fn register_user_agent(
-        &mut self,
-        actor: ActorRef<UserAgentSession>,
-        ctx: &mut Context<Self, ()>,
-    ) {
-        info!(id = %actor.id(), actor = "FlowCoordinator", event = "useragent.connected");
-        ctx.actor_ref().link(&actor).await;
-        self.user_agents.insert(actor.id(), actor);
-    }
-
     #[message(ctx)]
     pub async fn register_client(
         &mut self,
@@ -101,7 +93,11 @@ impl FlowCoordinator {
             unreachable!("Expected `request_client_approval` to have callback channel");
         };
 
-        let refs: Vec<_> = self.user_agents.values().cloned().collect();
+        let Ok(refs) = self.useragent_registry.ask(GetConnected).await else {
+            reply_sender.send(Err(ApprovalError::NoUserAgentsConnected));
+            return reply;
+        };
+
         if refs.is_empty() {
             reply_sender.send(Err(ApprovalError::NoUserAgentsConnected));
             return reply;

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

@@ -1,47 +1,59 @@
-use kameo::actor::{ActorRef, Spawn};
-use thiserror::Error;
-
 use crate::{
     actors::{
         bootstrap::Bootstrapper, evm::EvmActor, flow_coordinator::FlowCoordinator,
-        keyholder::KeyHolder,
+        useragent_registry::UserAgentRegistry, vault::Vault,
     },
     db,
 };
 
+use kameo::actor::{ActorRef, Spawn};
+use kameo_actors::{DeliveryStrategy, message_bus::MessageBus};
+use thiserror::Error;
+
 pub mod bootstrap;
-pub mod client;
-mod evm;
+pub mod evm;
 pub mod flow_coordinator;
-pub mod keyholder;
-pub mod user_agent;
+pub mod useragent_registry;
+pub mod vault;
 
 #[derive(Error, Debug)]
 pub enum SpawnError {
     #[error("Failed to spawn Bootstrapper actor")]
     Bootstrapper(#[from] bootstrap::Error),
 
-    #[error("Failed to spawn KeyHolder actor")]
-    KeyHolder(#[from] keyholder::Error),
+    #[error("Failed to spawn Vault actor")]
+    Vault(#[from] vault::Error),
 }
 
 /// Long-lived actors that are shared across all connections and handle global state and operations
 #[derive(Clone)]
 pub struct GlobalActors {
-    pub key_holder: ActorRef<KeyHolder>,
+    pub vault: ActorRef<Vault>,
     pub bootstrapper: ActorRef<Bootstrapper>,
     pub flow_coordinator: ActorRef<FlowCoordinator>,
+    pub useragent_registry: ActorRef<UserAgentRegistry>,
     pub evm: ActorRef<EvmActor>,
+    pub events: ActorRef<MessageBus>,
 }
 
 impl GlobalActors {
+    pub fn spawn_message_bus() -> ActorRef<MessageBus> {
+        MessageBus::spawn(MessageBus::new(DeliveryStrategy::Guaranteed))
+    }
+
     pub async fn spawn(db: db::DatabasePool) -> Result<Self, SpawnError> {
-        let key_holder = KeyHolder::spawn(KeyHolder::new(db.clone()).await?);
+        let message_bus = Self::spawn_message_bus();
+        let key_holder = Vault::spawn(Vault::new(db.clone(), message_bus.clone()).await?);
+        let useragent_registry = UserAgentRegistry::spawn(UserAgentRegistry::default());
         Ok(Self {
             bootstrapper: Bootstrapper::spawn(Bootstrapper::new(&db).await?),
             evm: EvmActor::spawn(EvmActor::new(key_holder.clone(), db)),
-            key_holder,
-            flow_coordinator: FlowCoordinator::spawn(FlowCoordinator::default()),
+            vault: key_holder,
+            flow_coordinator: FlowCoordinator::spawn(FlowCoordinator::new(
+                useragent_registry.clone(),
+            )),
+            useragent_registry,
+            events: message_bus,
         })
     }
 }

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

@@ -1,318 +0,0 @@
-use arbiter_crypto::authn::{self, USERAGENT_CONTEXT};
-use arbiter_proto::transport::Bi;
-use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl, update};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::actor::ActorRef;
-use tracing::error;
-
-use super::Error;
-use crate::{
-    actors::{
-        bootstrap::ConsumeToken,
-        keyholder::KeyHolder,
-        user_agent::{UserAgentConnection, UserAgentCredentials, auth::Outbound},
-    },
-    crypto::integrity,
-    db::{DatabasePool, schema::useragent_client},
-};
-
-pub struct ChallengeRequest {
-    pub pubkey: authn::PublicKey,
-}
-
-pub struct BootstrapAuthRequest {
-    pub pubkey: authn::PublicKey,
-    pub token: String,
-}
-
-pub struct ChallengeContext {
-    pub challenge_nonce: i32,
-    pub key: authn::PublicKey,
-}
-
-pub struct ChallengeSolution {
-    pub solution: Vec<u8>,
-}
-
-smlang::statemachine!(
-    name: Auth,
-    custom_error: true,
-    transitions: {
-        *Init + AuthRequest(ChallengeRequest) / async prepare_challenge = SentChallenge(ChallengeContext),
-        Init + BootstrapAuthRequest(BootstrapAuthRequest) / async verify_bootstrap_token = AuthOk(authn::PublicKey),
-        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) / async verify_solution = AuthOk(authn::PublicKey),
-    }
-);
-
-/// Returns the current nonce, ready to use for the challenge nonce.
-async fn get_current_nonce_and_id(
-    db: &DatabasePool,
-    key: &authn::PublicKey,
-) -> Result<(i32, i32), Error> {
-    let mut db_conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::internal("Database unavailable")
-    })?;
-    db_conn
-        .exclusive_transaction(|conn| {
-            Box::pin(async move {
-                useragent_client::table
-                    .filter(useragent_client::public_key.eq(key.to_bytes()))
-                    .select((useragent_client::id, useragent_client::nonce))
-                    .first::<(i32, i32)>(conn)
-                    .await
-            })
-        })
-        .await
-        .optional()
-        .map_err(|e| {
-            error!(error = ?e, "Database error");
-            Error::internal("Database operation failed")
-        })?
-        .ok_or_else(|| {
-            error!(?key, "Public key not found in database");
-            Error::UnregisteredPublicKey
-        })
-}
-
-async fn verify_integrity(
-    db: &DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
-    pubkey: &authn::PublicKey,
-) -> Result<(), Error> {
-    let mut db_conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::internal("Database unavailable")
-    })?;
-
-    let (id, nonce) = get_current_nonce_and_id(db, pubkey).await?;
-
-    let _result = integrity::verify_entity(
-        &mut db_conn,
-        keyholder,
-        &UserAgentCredentials {
-            pubkey: pubkey.clone(),
-            nonce,
-        },
-        id,
-    )
-    .await
-    .map_err(|e| {
-        error!(?e, "Integrity verification failed");
-        Error::internal("Integrity verification failed")
-    })?;
-
-    Ok(())
-}
-
-async fn create_nonce(
-    db: &DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
-    pubkey: &authn::PublicKey,
-) -> Result<i32, Error> {
-    let mut db_conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::internal("Database unavailable")
-    })?;
-    let new_nonce = db_conn
-        .exclusive_transaction(|conn| {
-            Box::pin(async move {
-                let (id, new_nonce): (i32, i32) = update(useragent_client::table)
-                    .filter(useragent_client::public_key.eq(pubkey.to_bytes()))
-                    .set(useragent_client::nonce.eq(useragent_client::nonce + 1))
-                    .returning((useragent_client::id, useragent_client::nonce))
-                    .get_result(conn)
-                    .await
-                    .map_err(|e| {
-                        error!(error = ?e, "Database error");
-                        Error::internal("Database operation failed")
-                    })?;
-
-                integrity::sign_entity(
-                    conn,
-                    keyholder,
-                    &UserAgentCredentials {
-                        pubkey: pubkey.clone(),
-                        nonce: new_nonce,
-                    },
-                    id,
-                )
-                .await
-                .map_err(|e| {
-                    error!(?e, "Integrity signature update failed");
-                    Error::internal("Database error")
-                })?;
-
-                Result::<_, Error>::Ok(new_nonce)
-            })
-        })
-        .await?;
-    Ok(new_nonce)
-}
-
-async fn register_key(
-    db: &DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
-    pubkey: &authn::PublicKey,
-) -> Result<(), Error> {
-    let pubkey_bytes = pubkey.to_bytes();
-    let mut conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::internal("Database unavailable")
-    })?;
-
-    conn.transaction(|conn| {
-        Box::pin(async move {
-            const NONCE_START: i32 = 1;
-
-            let id: i32 = diesel::insert_into(useragent_client::table)
-                .values((
-                    useragent_client::public_key.eq(pubkey_bytes),
-                    useragent_client::nonce.eq(NONCE_START),
-                ))
-                .returning(useragent_client::id)
-                .get_result(conn)
-                .await
-                .map_err(|e| {
-                    error!(error = ?e, "Database error");
-                    Error::internal("Database operation failed")
-                })?;
-
-            let entity = UserAgentCredentials {
-                pubkey: pubkey.clone(),
-                nonce: NONCE_START,
-            };
-
-            integrity::sign_entity(conn, keyholder, &entity, id)
-                .await
-                .map_err(|e| {
-                    error!(error = ?e, "Failed to sign integrity tag for new user-agent key");
-                    Error::internal("Failed to register public key")
-                })?;
-
-            Result::<_, Error>::Ok(())
-        })
-    })
-    .await?;
-
-    Ok(())
-}
-
-pub struct AuthContext<'a, T> {
-    pub(super) conn: &'a mut UserAgentConnection,
-    pub(super) transport: T,
-}
-
-impl<'a, T> AuthContext<'a, T> {
-    pub fn new(conn: &'a mut UserAgentConnection, transport: T) -> Self {
-        Self { conn, transport }
-    }
-}
-
-impl<T> AuthStateMachineContext for AuthContext<'_, T>
-where
-    T: Bi<super::Inbound, Result<super::Outbound, Error>> + Send,
-{
-    type Error = Error;
-
-    async fn prepare_challenge(
-        &mut self,
-        ChallengeRequest { pubkey }: ChallengeRequest,
-    ) -> Result<ChallengeContext, Self::Error> {
-        verify_integrity(&self.conn.db, &self.conn.actors.key_holder, &pubkey).await?;
-
-        let nonce = create_nonce(&self.conn.db, &self.conn.actors.key_holder, &pubkey).await?;
-
-        self.transport
-            .send(Ok(Outbound::AuthChallenge { nonce }))
-            .await
-            .map_err(|e| {
-                error!(?e, "Failed to send auth challenge");
-                Error::Transport
-            })?;
-
-        Ok(ChallengeContext {
-            challenge_nonce: nonce,
-            key: pubkey,
-        })
-    }
-
-    #[allow(missing_docs)]
-    #[allow(clippy::result_unit_err)]
-    async fn verify_bootstrap_token(
-        &mut self,
-        BootstrapAuthRequest { pubkey, token }: BootstrapAuthRequest,
-    ) -> Result<authn::PublicKey, Self::Error> {
-        let token_ok: bool = self
-            .conn
-            .actors
-            .bootstrapper
-            .ask(ConsumeToken {
-                token: token.clone(),
-            })
-            .await
-            .map_err(|e| {
-                error!(?e, "Failed to consume bootstrap token");
-                Error::internal("Failed to consume bootstrap token")
-            })?;
-
-        if !token_ok {
-            error!("Invalid bootstrap token provided");
-            return Err(Error::InvalidBootstrapToken);
-        }
-
-        match token_ok {
-            true => {
-                register_key(&self.conn.db, &self.conn.actors.key_holder, &pubkey).await?;
-                self.transport
-                    .send(Ok(Outbound::AuthSuccess))
-                    .await
-                    .map_err(|_| Error::Transport)?;
-                Ok(pubkey)
-            }
-            false => {
-                error!("Invalid bootstrap token provided");
-                self.transport
-                    .send(Err(Error::InvalidBootstrapToken))
-                    .await
-                    .map_err(|_| Error::Transport)?;
-                Err(Error::InvalidBootstrapToken)
-            }
-        }
-    }
-
-    #[allow(missing_docs)]
-    #[allow(clippy::unused_unit)]
-    async fn verify_solution(
-        &mut self,
-        ChallengeContext {
-            challenge_nonce,
-            key,
-        }: &ChallengeContext,
-        ChallengeSolution { solution }: ChallengeSolution,
-    ) -> Result<authn::PublicKey, Self::Error> {
-        let signature = authn::Signature::try_from(solution.as_slice()).map_err(|_| {
-            error!("Failed to decode signature in challenge solution");
-            Error::InvalidChallengeSolution
-        })?;
-
-        let valid = key.verify(*challenge_nonce, USERAGENT_CONTEXT, &signature);
-
-        match valid {
-            true => {
-                self.transport
-                    .send(Ok(Outbound::AuthSuccess))
-                    .await
-                    .map_err(|_| Error::Transport)?;
-                Ok(key.clone())
-            }
-            false => {
-                self.transport
-                    .send(Err(Error::InvalidChallengeSolution))
-                    .await
-                    .map_err(|_| Error::Transport)?;
-                Err(Error::InvalidChallengeSolution)
-            }
-        }
-    }
-}

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

@@ -1,40 +0,0 @@
-use crate::{
-    actors::{GlobalActors, client::ClientProfile},
-    crypto::integrity::Integrable,
-    db,
-};
-use arbiter_crypto::authn;
-
-#[derive(Debug, arbiter_macros::Hashable)]
-pub struct UserAgentCredentials {
-    pub pubkey: authn::PublicKey,
-    pub nonce: i32,
-}
-
-impl Integrable for UserAgentCredentials {
-    const KIND: &'static str = "useragent_credentials";
-}
-
-// Messages, sent by user agent to connection client without having a request
-#[derive(Debug)]
-pub enum OutOfBand {
-    ClientConnectionRequest { profile: ClientProfile },
-    ClientConnectionCancel { pubkey: authn::PublicKey },
-}
-
-pub struct UserAgentConnection {
-    pub(crate) db: db::DatabasePool,
-    pub(crate) actors: GlobalActors,
-}
-
-impl UserAgentConnection {
-    pub fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
-        Self { db, actors }
-    }
-}
-
-pub mod auth;
-pub mod session;
-
-pub use auth::authenticate;
-pub use session::UserAgentSession;

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

@@ -1,524 +0,0 @@
-use std::sync::Mutex;
-
-use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
-use arbiter_crypto::{
-    authn,
-    safecell::{SafeCell, SafeCellHandle as _},
-};
-use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
-use diesel::{ExpressionMethods as _, QueryDsl as _, SelectableHelper};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::error::SendError;
-use kameo::messages;
-use kameo::prelude::Context;
-use tracing::{error, info};
-use x25519_dalek::{EphemeralSecret, PublicKey};
-
-use crate::actors::flow_coordinator::client_connect_approval::ClientApprovalAnswer;
-use crate::actors::keyholder::KeyHolderState;
-use crate::actors::user_agent::session::Error;
-use crate::actors::{
-    evm::{
-        ClientSignTransaction, Generate, ListWallets, SignTransactionError as EvmSignError,
-        UseragentCreateGrant, UseragentListGrants,
-    },
-    keyholder::{self, Bootstrap, TryUnseal},
-    user_agent::session::{
-        UserAgentSession,
-        state::{UnsealContext, UserAgentEvents, UserAgentStates},
-    },
-};
-use crate::db::models::{
-    EvmWalletAccess, NewEvmWalletAccess, ProgramClient, ProgramClientMetadata,
-};
-use crate::evm::policies::{Grant, SpecificGrant};
-
-impl UserAgentSession {
-    fn take_unseal_secret(&mut self) -> Result<(EphemeralSecret, PublicKey), Error> {
-        let UserAgentStates::WaitingForUnsealKey(unseal_context) = self.state.state() else {
-            error!("Received encrypted key in invalid state");
-            return Err(Error::internal("Invalid state for unseal encrypted key"));
-        };
-
-        let ephemeral_secret = {
-            #[allow(
-                clippy::unwrap_used,
-                reason = "Mutex poison is unrecoverable and should panic"
-            )]
-            let mut secret_lock = unseal_context.secret.lock().unwrap();
-            let secret = secret_lock.take();
-            match secret {
-                Some(secret) => secret,
-                None => {
-                    drop(secret_lock);
-                    error!("Ephemeral secret already taken");
-                    return Err(Error::internal("Ephemeral secret already taken"));
-                }
-            }
-        };
-
-        Ok((ephemeral_secret, unseal_context.client_public_key))
-    }
-
-    fn decrypt_client_key_material(
-        ephemeral_secret: EphemeralSecret,
-        client_public_key: PublicKey,
-        nonce: &[u8],
-        ciphertext: &[u8],
-        associated_data: &[u8],
-    ) -> Result<SafeCell<Vec<u8>>, ()> {
-        let nonce = XNonce::from_slice(nonce);
-
-        let shared_secret = ephemeral_secret.diffie_hellman(&client_public_key);
-        let cipher = XChaCha20Poly1305::new(shared_secret.as_bytes().into());
-
-        let mut key_buffer = SafeCell::new(ciphertext.to_vec());
-
-        let decryption_result = key_buffer.write_inline(|write_handle| {
-            cipher.decrypt_in_place(nonce, associated_data, write_handle)
-        });
-
-        match decryption_result {
-            Ok(_) => Ok(key_buffer),
-            Err(err) => {
-                error!(?err, "Failed to decrypt encrypted key material");
-                Err(())
-            }
-        }
-    }
-}
-
-pub struct UnsealStartResponse {
-    pub server_pubkey: PublicKey,
-}
-
-#[derive(Debug, Error)]
-pub enum UnsealError {
-    #[error("Invalid key provided for unsealing")]
-    InvalidKey,
-    #[error("Internal error during unsealing process")]
-    General(#[from] super::Error),
-}
-
-#[derive(Debug, Error)]
-pub enum BootstrapError {
-    #[error("Invalid key provided for bootstrapping")]
-    InvalidKey,
-    #[error("Vault is already bootstrapped")]
-    AlreadyBootstrapped,
-
-    #[error("Internal error during bootstrapping process")]
-    General(#[from] super::Error),
-}
-
-#[derive(Debug, Error)]
-pub enum SignTransactionError {
-    #[error("Policy evaluation failed")]
-    Vet(#[from] crate::evm::VetError),
-
-    #[error("Internal signing error")]
-    Internal,
-}
-
-#[derive(Debug, Error)]
-pub enum GrantMutationError {
-    #[error("Vault is sealed")]
-    VaultSealed,
-
-    #[error("Internal grant mutation error")]
-    Internal,
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub async fn handle_unseal_request(
-        &mut self,
-        client_pubkey: x25519_dalek::PublicKey,
-    ) -> Result<UnsealStartResponse, Error> {
-        let secret = EphemeralSecret::random();
-        let public_key = PublicKey::from(&secret);
-
-        self.transition(UserAgentEvents::UnsealRequest(UnsealContext {
-            secret: Mutex::new(Some(secret)),
-            client_public_key: client_pubkey,
-        }))?;
-
-        Ok(UnsealStartResponse {
-            server_pubkey: public_key,
-        })
-    }
-
-    #[message]
-    pub async fn handle_unseal_encrypted_key(
-        &mut self,
-        nonce: Vec<u8>,
-        ciphertext: Vec<u8>,
-        associated_data: Vec<u8>,
-    ) -> Result<(), UnsealError> {
-        let (ephemeral_secret, client_public_key) = match self.take_unseal_secret() {
-            Ok(values) => values,
-            Err(Error::State) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(UnsealError::InvalidKey);
-            }
-            Err(_err) => {
-                return Err(Error::internal("Failed to take unseal secret").into());
-            }
-        };
-
-        let seal_key_buffer = match Self::decrypt_client_key_material(
-            ephemeral_secret,
-            client_public_key,
-            &nonce,
-            &ciphertext,
-            &associated_data,
-        ) {
-            Ok(buffer) => buffer,
-            Err(()) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(UnsealError::InvalidKey);
-            }
-        };
-
-        match self
-            .props
-            .actors
-            .key_holder
-            .ask(TryUnseal {
-                seal_key_raw: seal_key_buffer,
-            })
-            .await
-        {
-            Ok(_) => {
-                info!("Successfully unsealed key with client-provided key");
-                self.transition(UserAgentEvents::ReceivedValidKey)?;
-                Ok(())
-            }
-            Err(SendError::HandlerError(keyholder::Error::InvalidKey)) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(UnsealError::InvalidKey)
-            }
-            Err(SendError::HandlerError(err)) => {
-                error!(?err, "Keyholder failed to unseal key");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(UnsealError::InvalidKey)
-            }
-            Err(err) => {
-                error!(?err, "Failed to send unseal request to keyholder");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(Error::internal("Vault actor error").into())
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_bootstrap_encrypted_key(
-        &mut self,
-        nonce: Vec<u8>,
-        ciphertext: Vec<u8>,
-        associated_data: Vec<u8>,
-    ) -> Result<(), BootstrapError> {
-        let (ephemeral_secret, client_public_key) = match self.take_unseal_secret() {
-            Ok(values) => values,
-            Err(Error::State) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(BootstrapError::InvalidKey);
-            }
-            Err(err) => return Err(err.into()),
-        };
-
-        let seal_key_buffer = match Self::decrypt_client_key_material(
-            ephemeral_secret,
-            client_public_key,
-            &nonce,
-            &ciphertext,
-            &associated_data,
-        ) {
-            Ok(buffer) => buffer,
-            Err(()) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(BootstrapError::InvalidKey);
-            }
-        };
-
-        match self
-            .props
-            .actors
-            .key_holder
-            .ask(Bootstrap {
-                seal_key_raw: seal_key_buffer,
-            })
-            .await
-        {
-            Ok(_) => {
-                info!("Successfully bootstrapped vault with client-provided key");
-                self.transition(UserAgentEvents::ReceivedValidKey)?;
-                Ok(())
-            }
-            Err(SendError::HandlerError(keyholder::Error::AlreadyBootstrapped)) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::AlreadyBootstrapped)
-            }
-            Err(SendError::HandlerError(err)) => {
-                error!(?err, "Keyholder failed to bootstrap vault");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::InvalidKey)
-            }
-            Err(err) => {
-                error!(?err, "Failed to send bootstrap request to keyholder");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::General(Error::internal(
-                    "Vault actor error",
-                )))
-            }
-        }
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<KeyHolderState, Error> {
-        use crate::actors::keyholder::GetState;
-
-        let vault_state = match self.props.actors.key_holder.ask(GetState {}).await {
-            Ok(state) => state,
-            Err(err) => {
-                error!(?err, actor = "useragent", "keyholder.query.failed");
-                return Err(Error::internal("Vault is in broken state"));
-            }
-        };
-
-        Ok(vault_state)
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub(crate) async fn handle_evm_wallet_create(&mut self) -> Result<(i32, Address), Error> {
-        match self.props.actors.evm.ask(Generate {}).await {
-            Ok(address) => Ok(address),
-            Err(SendError::HandlerError(err)) => Err(Error::internal(format!(
-                "EVM wallet generation failed: {err}"
-            ))),
-            Err(err) => {
-                error!(?err, "EVM actor unreachable during wallet create");
-                Err(Error::internal("EVM actor unreachable"))
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_evm_wallet_list(&mut self) -> Result<Vec<(i32, Address)>, Error> {
-        match self.props.actors.evm.ask(ListWallets {}).await {
-            Ok(wallets) => Ok(wallets),
-            Err(err) => {
-                error!(?err, "EVM wallet list failed");
-                Err(Error::internal("Failed to list EVM wallets"))
-            }
-        }
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub(crate) async fn handle_grant_list(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
-        match self.props.actors.evm.ask(UseragentListGrants {}).await {
-            Ok(grants) => Ok(grants),
-            Err(err) => {
-                error!(?err, "EVM grant list failed");
-                Err(Error::internal("Failed to list EVM grants"))
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_grant_create(
-        &mut self,
-        basic: crate::evm::policies::SharedGrantSettings,
-        grant: crate::evm::policies::SpecificGrant,
-    ) -> Result<i32, GrantMutationError> {
-        match self
-            .props
-            .actors
-            .evm
-            .ask(UseragentCreateGrant { basic, grant })
-            .await
-        {
-            Ok(grant_id) => Ok(grant_id),
-            Err(err) => {
-                error!(?err, "EVM grant create failed");
-                Err(GrantMutationError::Internal)
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_grant_delete(
-        &mut self,
-        grant_id: i32,
-    ) -> Result<(), GrantMutationError> {
-        // match self
-        //     .props
-        //     .actors
-        //     .evm
-        //     .ask(UseragentDeleteGrant { grant_id })
-        //     .await
-        // {
-        //     Ok(()) => Ok(()),
-        //     Err(err) => {
-        //         error!(?err, "EVM grant delete failed");
-        //         Err(GrantMutationError::Internal)
-        //     }
-        // }
-       let _ = grant_id;
-        todo!()
-    }
-
-    #[message]
-    pub(crate) async fn handle_sign_transaction(
-        &mut self,
-        client_id: i32,
-        wallet_address: Address,
-        transaction: TxEip1559,
-    ) -> Result<Signature, SignTransactionError> {
-        match self
-            .props
-            .actors
-            .evm
-            .ask(ClientSignTransaction {
-                client_id,
-                wallet_address,
-                transaction,
-            })
-            .await
-        {
-            Ok(signature) => Ok(signature),
-            Err(SendError::HandlerError(EvmSignError::Vet(vet_error))) => {
-                Err(SignTransactionError::Vet(vet_error))
-            }
-            Err(err) => {
-                error!(?err, "EVM sign transaction failed in user-agent session");
-                Err(SignTransactionError::Internal)
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_grant_evm_wallet_access(
-        &mut self,
-        entries: Vec<NewEvmWalletAccess>,
-    ) -> Result<(), Error> {
-        let mut conn = self.props.db.get().await?;
-        conn.transaction(|conn| {
-            Box::pin(async move {
-                use crate::db::schema::evm_wallet_access;
-
-                for entry in entries {
-                    diesel::insert_into(evm_wallet_access::table)
-                        .values(&entry)
-                        .on_conflict_do_nothing()
-                        .execute(conn)
-                        .await?;
-                }
-
-                Result::<_, Error>::Ok(())
-            })
-        })
-        .await?;
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_revoke_evm_wallet_access(
-        &mut self,
-        entries: Vec<i32>,
-    ) -> Result<(), Error> {
-        let mut conn = self.props.db.get().await?;
-        conn.transaction(|conn| {
-            Box::pin(async move {
-                use crate::db::schema::evm_wallet_access;
-                for entry in entries {
-                    diesel::delete(evm_wallet_access::table)
-                        .filter(evm_wallet_access::wallet_id.eq(entry))
-                        .execute(conn)
-                        .await?;
-                }
-
-                Result::<_, Error>::Ok(())
-            })
-        })
-        .await?;
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_list_wallet_access(
-        &mut self,
-    ) -> Result<Vec<EvmWalletAccess>, Error> {
-        let mut conn = self.props.db.get().await?;
-        use crate::db::schema::evm_wallet_access;
-        let access_entries = evm_wallet_access::table
-            .select(EvmWalletAccess::as_select())
-            .load::<_>(&mut conn)
-            .await?;
-        Ok(access_entries)
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message(ctx)]
-    pub(crate) async fn handle_new_client_approve(
-        &mut self,
-        approved: bool,
-        pubkey: authn::PublicKey,
-        ctx: &mut Context<Self, Result<(), Error>>,
-    ) -> Result<(), Error> {
-        let pending_approval = match self.pending_client_approvals.remove(&pubkey.to_bytes()) {
-            Some(approval) => approval,
-            None => {
-                error!("Received client connection response for unknown client");
-                return Err(Error::internal("Unknown client in connection response"));
-            }
-        };
-
-        pending_approval
-            .controller
-            .tell(ClientApprovalAnswer { approved })
-            .await
-            .map_err(|err| {
-                error!(
-                    ?err,
-                    "Failed to send client approval response to controller"
-                );
-                Error::internal("Failed to send client approval response to controller")
-            })?;
-
-        ctx.actor_ref().unlink(&pending_approval.controller).await;
-
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_sdk_client_list(
-        &mut self,
-    ) -> Result<Vec<(ProgramClient, ProgramClientMetadata)>, Error> {
-        use crate::db::schema::{client_metadata, program_client};
-        let mut conn = self.props.db.get().await?;
-
-        let clients = program_client::table
-            .inner_join(client_metadata::table)
-            .select((
-                ProgramClient::as_select(),
-                ProgramClientMetadata::as_select(),
-            ))
-            .load::<(ProgramClient, ProgramClientMetadata)>(&mut conn)
-            .await?;
-
-        Ok(clients)
-    }
-}

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

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

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

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

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

@@ -1,46 +1,49 @@
+use crate::{
+    crypto::{
+        KeyCell, derive_key,
+        encryption::v1::{self, Nonce},
+        integrity::v1::HmacSha256,
+    },
+    db::{
+        self,
+        models::{self, RootKeyHistory},
+        schema::{self},
+    },
+};
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+
 use chrono::Utc;
 use diesel::{
     ExpressionMethods as _, OptionalExtension, QueryDsl, SelectableHelper,
     dsl::{insert_into, update},
 };
 use diesel_async::{AsyncConnection, RunQueryDsl};
-use hmac::Mac as _;
-use kameo::{Actor, Reply, messages};
+use hmac::{KeyInit as _, Mac as _};
+use kameo::{Actor, Reply, actor::ActorRef, messages};
+use kameo_actors::message_bus::{MessageBus, Publish};
 use strum::{EnumDiscriminants, IntoDiscriminant};
 use tracing::{error, info};
 
-use crate::crypto::{
-    KeyCell, derive_key,
-    encryption::v1::{self, Nonce},
-    integrity::v1::HmacSha256,
-};
-use crate::db::{
-    self,
-    models::{self, RootKeyHistory},
-    schema::{self},
-};
-use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+pub mod events {
 
-#[derive(Default, EnumDiscriminants)]
-#[strum_discriminants(derive(Reply), vis(pub), name(KeyHolderState))]
-enum State {
-    #[default]
-    Unbootstrapped,
-    Sealed {
-        root_key_history_id: i32,
-    },
-    Unsealed {
-        root_key_history_id: i32,
-        root_key: KeyCell,
-    },
+    #[derive(Clone, Copy)]
+    pub struct Bootstrapped;
+
+    #[derive(Clone, Copy)]
+    pub struct Unsealed;
+
+    #[derive(Clone, Copy)]
+    pub struct VaultResealed;
 }
 
 #[derive(Debug, thiserror::Error)]
 pub enum Error {
-    #[error("Keyholder is already bootstrapped")]
+    #[error("Vault is already bootstrapped")]
     AlreadyBootstrapped,
-    #[error("Keyholder is not bootstrapped")]
+    #[error("Vault is not bootstrapped")]
     NotBootstrapped,
+    #[error("Vault is sealed")]
+    Sealed,
     #[error("Invalid key provided")]
     InvalidKey,
 
@@ -60,18 +63,36 @@ pub enum Error {
     BrokenDatabase,
 }
 
+struct Unsealed {
+    root_key_history_id: i32,
+    root_key: KeyCell,
+}
+
+#[derive(Default, EnumDiscriminants)]
+#[strum_discriminants(derive(Reply), vis(pub), name(VaultState))]
+enum State {
+    #[default]
+    Unbootstrapped,
+    Sealed {
+        root_key_history_id: i32,
+    },
+    Unsealed(Unsealed),
+}
+
 /// Manages vault root key and tracks current state of the vault (bootstrapped/unbootstrapped, sealed/unsealed).
+///
 /// Provides API for encrypting and decrypting data using the vault root key.
 /// Abstraction over database to make sure nonces are never reused and encryption keys are never exposed in plaintext outside of this actor.
 #[derive(Actor)]
-pub struct KeyHolder {
+pub struct Vault {
     db: db::DatabasePool,
     state: State,
+    events: ActorRef<MessageBus>,
 }
 
 #[messages]
-impl KeyHolder {
-    pub async fn new(db: db::DatabasePool) -> Result<Self, Error> {
+impl Vault {
+    pub async fn new(db: db::DatabasePool, events: ActorRef<MessageBus>) -> Result<Self, Error> {
         let state = {
             let mut conn = db.get().await?;
 
@@ -89,10 +110,10 @@ impl KeyHolder {
             }
         };
 
-        Ok(Self { db, state })
+        Ok(Self { db, state, events })
     }
 
-    // Exclusive transaction to avoid race condtions if multiple keyholders write
+    // Exclusive transaction to avoid race condtions if multiple vaults write
     // additional layer of protection against nonce-reuse
     async fn get_new_nonce(pool: &db::DatabasePool, root_key_id: i32) -> Result<Nonce, Error> {
         let mut conn = pool.get().await?;
@@ -106,7 +127,7 @@ impl KeyHolder {
                         .first(conn)
                         .await?;
 
-                    let mut nonce = Nonce::try_from(current_nonce.as_slice()).map_err(|_| {
+                    let mut nonce = Nonce::try_from(current_nonce.as_slice()).map_err(|()| {
                         error!(
                             "Broken database: invalid nonce for root key history id={}",
                             root_key_id
@@ -129,6 +150,14 @@ impl KeyHolder {
         Ok(nonce)
     }
 
+    const fn expect_unsealed(state: &mut State) -> Result<&mut Unsealed, Error> {
+        match state {
+            State::Unsealed(unsealed) => Ok(unsealed),
+            State::Unbootstrapped => Err(Error::NotBootstrapped),
+            State::Sealed { .. } => Err(Error::Sealed),
+        }
+    }
+
     #[message]
     pub async fn bootstrap(&mut self, seal_key_raw: SafeCell<Vec<u8>>) -> Result<(), Error> {
         if !matches!(self.state, State::Unbootstrapped) {
@@ -181,12 +210,13 @@ impl KeyHolder {
             })
             .await?;
 
-        self.state = State::Unsealed {
+        self.state = State::Unsealed(Unsealed {
             root_key,
             root_key_history_id,
-        };
+        });
 
-        info!("Keyholder bootstrapped successfully");
+        info!("Vault bootstrapped successfully");
+        let _ = self.events.tell(Publish(events::Bootstrapped)).await;
 
         Ok(())
     }
@@ -219,12 +249,11 @@ impl KeyHolder {
 
         let mut root_key = SafeCell::new(current_key.ciphertext.clone());
 
-        let nonce = v1::Nonce::try_from(current_key.root_key_encryption_nonce.as_slice()).map_err(
-            |_| {
+        let nonce =
+            Nonce::try_from(current_key.root_key_encryption_nonce.as_slice()).map_err(|()| {
                 error!("Broken database: invalid nonce for root key");
                 Error::BrokenDatabase
-            },
-        )?;
+            })?;
 
         seal_key
             .decrypt_in_place(&nonce, v1::ROOT_KEY_TAG, &mut root_key)
@@ -233,24 +262,23 @@ impl KeyHolder {
                 Error::InvalidKey
             })?;
 
-        self.state = State::Unsealed {
+        self.state = State::Unsealed(Unsealed {
             root_key_history_id: current_key.id,
             root_key: KeyCell::try_from(root_key).map_err(|err| {
                 error!(?err, "Broken database: invalid encryption key size");
                 Error::BrokenDatabase
             })?,
-        };
+        });
 
-        info!("Keyholder unsealed successfully");
+        info!("Vault unsealed successfully");
+        let _ = self.events.tell(Publish(events::Unsealed)).await;
 
         Ok(())
     }
 
     #[message]
     pub async fn decrypt(&mut self, aead_id: i32) -> Result<SafeCell<Vec<u8>>, Error> {
-        let State::Unsealed { root_key, .. } = &mut self.state else {
-            return Err(Error::NotBootstrapped);
-        };
+        let Unsealed { root_key, .. } = Self::expect_unsealed(&mut self.state)?;
 
         let row: models::AeadEncrypted = {
             let mut conn = self.db.get().await?;
@@ -263,7 +291,7 @@ impl KeyHolder {
                 .ok_or(Error::NotFound)?
         };
 
-        let nonce = v1::Nonce::try_from(row.current_nonce.as_slice()).map_err(|_| {
+        let nonce = Nonce::try_from(row.current_nonce.as_slice()).map_err(|()| {
             error!(
                 "Broken database: invalid nonce for aead_encrypted id={}",
                 aead_id
@@ -278,14 +306,10 @@ impl KeyHolder {
     // Creates new `aead_encrypted` entry in the database and returns it's ID
     #[message]
     pub async fn create_new(&mut self, mut plaintext: SafeCell<Vec<u8>>) -> Result<i32, Error> {
-        let State::Unsealed {
+        let Unsealed {
             root_key,
             root_key_history_id,
-            ..
-        } = &mut self.state
-        else {
-            return Err(Error::NotBootstrapped);
-        };
+        } = Self::expect_unsealed(&mut self.state)?;
 
         // Order matters here - `get_new_nonce` acquires connection, so we need to call it before next acquire
         // Borrow checker note: &mut borrow a few lines above is disjoint from this field
@@ -315,19 +339,16 @@ impl KeyHolder {
     }
 
     #[message]
-    pub fn get_state(&self) -> KeyHolderState {
+    pub fn get_state(&self) -> VaultState {
         self.state.discriminant()
     }
 
     #[message]
     pub fn sign_integrity(&mut self, mac_input: Vec<u8>) -> Result<(i32, Vec<u8>), Error> {
-        let State::Unsealed {
+        let Unsealed {
             root_key,
             root_key_history_id,
-        } = &mut self.state
-        else {
-            return Err(Error::NotBootstrapped);
-        };
+        } = Self::expect_unsealed(&mut self.state)?;
 
         let mut hmac = root_key
             .0
@@ -349,13 +370,10 @@ impl KeyHolder {
         expected_mac: Vec<u8>,
         key_version: i32,
     ) -> Result<bool, Error> {
-        let State::Unsealed {
+        let Unsealed {
             root_key,
             root_key_history_id,
-        } = &mut self.state
-        else {
-            return Err(Error::NotBootstrapped);
-        };
+        } = Self::expect_unsealed(&mut self.state)?;
 
         if *root_key_history_id != key_version {
             return Ok(false);
@@ -374,34 +392,31 @@ impl KeyHolder {
     }
 
     #[message]
-    pub fn seal(&mut self) -> Result<(), Error> {
-        let State::Unsealed {
+    pub async fn seal(&mut self) -> Result<(), Error> {
+        let Unsealed {
             root_key_history_id,
             ..
-        } = &self.state
-        else {
-            return Err(Error::NotBootstrapped);
-        };
+        } = Self::expect_unsealed(&mut self.state)?;
+
         self.state = State::Sealed {
             root_key_history_id: *root_key_history_id,
         };
+        let _ = self.events.tell(Publish(events::VaultResealed)).await;
         Ok(())
     }
 }
 
 #[cfg(test)]
 mod tests {
-    use diesel::SelectableHelper;
-
-    use diesel_async::RunQueryDsl;
-
-    use crate::db::{self};
-    use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+    use crate::actors::GlobalActors;
+    use arbiter_crypto::safecell::SafeCellHandle as _;
 
     use super::*;
 
-    async fn bootstrapped_actor(db: &db::DatabasePool) -> KeyHolder {
-        let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    async fn bootstrapped_actor(db: &db::DatabasePool) -> Vault {
+        let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+            .await
+            .unwrap();
         let seal_key = SafeCell::new(b"test-seal-key".to_vec());
         actor.bootstrap(seal_key).await.unwrap();
         actor
@@ -413,17 +428,17 @@ mod tests {
         let db = db::create_test_pool().await;
         let mut actor = bootstrapped_actor(&db).await;
         let root_key_history_id = match actor.state {
-            State::Unsealed {
+            State::Unsealed(Unsealed {
                 root_key_history_id,
                 ..
-            } => root_key_history_id,
+            }) => root_key_history_id,
             _ => panic!("expected unsealed state"),
         };
 
-        let n1 = KeyHolder::get_new_nonce(&db, root_key_history_id)
+        let n1 = Vault::get_new_nonce(&db, root_key_history_id)
             .await
             .unwrap();
-        let n2 = KeyHolder::get_new_nonce(&db, root_key_history_id)
+        let n2 = Vault::get_new_nonce(&db, root_key_history_id)
             .await
             .unwrap();
         assert!(n2.to_vec() > n1.to_vec(), "nonce must increase");

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

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

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

@@ -1,17 +1,3 @@
-use std::{net::Ipv4Addr, string::FromUtf8Error};
-
-use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper as _};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-
-use pem::Pem;
-use rcgen::{
-    BasicConstraints, Certificate, CertificateParams, CertifiedIssuer, DistinguishedName, DnType,
-    IsCa, Issuer, KeyPair, KeyUsagePurpose, SanType,
-};
-use rustls::pki_types::pem::PemObject;
-use thiserror::Error;
-use tonic::transport::CertificateDer;
-
 use crate::db::{
     self,
     models::{NewTlsHistory, TlsHistory},
@@ -21,10 +7,23 @@ use crate::db::{
     },
 };
 
+use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper as _};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use pem::Pem;
+use rcgen::{
+    BasicConstraints, Certificate, CertificateParams, CertifiedIssuer, DistinguishedName, DnType,
+    IsCa, Issuer, KeyPair, KeyUsagePurpose, SanType,
+};
+use rustls::pki_types::pem::PemObject;
+use std::{net::Ipv4Addr, string::FromUtf8Error};
+use thiserror::Error;
+use tonic::transport::CertificateDer;
+
 const ENCODE_CONFIG: pem::EncodeConfig = {
-    let line_ending = match cfg!(target_family = "windows") {
-        true => pem::LineEnding::CRLF,
-        false => pem::LineEnding::LF,
+    let line_ending = if cfg!(target_family = "windows") {
+        pem::LineEnding::CRLF
+    } else {
+        pem::LineEnding::LF
     };
     pem::EncodeConfig::new().set_line_ending(line_ending)
 };
@@ -52,11 +51,14 @@ pub enum InitError {
 
 pub type PemCert = String;
 
-pub fn encode_cert_to_pem(cert: &CertificateDer) -> PemCert {
+pub fn encode_cert_to_pem(cert: &CertificateDer<'_>) -> PemCert {
     pem::encode_config(&Pem::new("CERTIFICATE", cert.to_vec()), ENCODE_CONFIG)
 }
 
-#[allow(unused)]
+#[expect(
+    unused,
+    reason = "may be needed for future cert rotation implementation"
+)]
 struct SerializedTls {
     cert_pem: PemCert,
     cert_key_pem: String,
@@ -85,7 +87,7 @@ impl TlsCa {
 
         let cert_key_pem = certified_issuer.key().serialize_pem();
 
-        #[allow(
+        #[expect(
             clippy::unwrap_used,
             reason = "Broken cert couldn't bootstrap server anyway"
         )]
@@ -124,7 +126,11 @@ impl TlsCa {
         })
     }
 
-    #[allow(unused)]
+    #[expect(
+        unused,
+        clippy::unnecessary_wraps,
+        reason = "may be needed for future cert rotation implementation"
+    )]
     fn serialize(&self) -> Result<SerializedTls, InitError> {
         let cert_key_pem = self.issuer.key().serialize_pem();
         Ok(SerializedTls {
@@ -133,7 +139,10 @@ impl TlsCa {
         })
     }
 
-    #[allow(unused)]
+    #[expect(
+        unused,
+        reason = "may be needed for future cert rotation implementation"
+    )]
     fn try_deserialize(cert_pem: &str, cert_key_pem: &str) -> Result<Self, InitError> {
         let keypair =
             KeyPair::from_pem(cert_key_pem).map_err(InitError::KeyDeserializationError)?;
@@ -234,10 +243,10 @@ impl TlsManager {
         }
     }
 
-    pub fn cert(&self) -> &CertificateDer<'static> {
+    pub const fn cert(&self) -> &CertificateDer<'static> {
         &self.cert
     }
-    pub fn ca_cert(&self) -> &CertificateDer<'static> {
+    pub const fn ca_cert(&self) -> &CertificateDer<'static> {
         &self.ca_cert
     }
 

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

@@ -1,12 +1,11 @@
 use argon2::password_hash::Salt as ArgonSalt;
-
 use rand::{
     Rng as _, SeedableRng,
     rngs::{StdRng, SysRng},
 };
 
-pub const ROOT_KEY_TAG: &[u8] = "arbiter/seal/v1".as_bytes();
-pub const TAG: &[u8] = "arbiter/private-key/v1".as_bytes();
+pub const ROOT_KEY_TAG: &[u8] = b"arbiter/seal/v1";
+pub const TAG: &[u8] = b"arbiter/private-key/v1";
 
 pub const NONCE_LENGTH: usize = 24;
 
@@ -15,14 +14,16 @@ pub struct Nonce(pub [u8; NONCE_LENGTH]);
 impl Nonce {
     pub fn increment(&mut self) {
         for i in (0..self.0.len()).rev() {
-            if self.0[i] == 0xFF {
-                self.0[i] = 0;
+            if let Some(byte) = self.0.get_mut(i) {
+                if *byte == 0xFF {
+                    *byte = 0;
                 } else {
-                self.0[i] += 1;
+                    *byte += 1;
                     break;
                 }
             }
         }
+    }
 
     pub fn to_vec(&self) -> Vec<u8> {
         self.0.to_vec()
@@ -45,25 +46,20 @@ pub type Salt = [u8; ArgonSalt::RECOMMENDED_LENGTH];
 
 pub fn generate_salt() -> Salt {
     let mut salt = Salt::default();
-    #[allow(
-        clippy::unwrap_used,
-        reason = "Rng failure is unrecoverable and should panic"
-    )]
-    let mut rng = StdRng::try_from_rng(&mut SysRng).unwrap();
+    let mut rng =
+        StdRng::try_from_rng(&mut SysRng).expect("Rng failure is unrecoverable and should panic");
     rng.fill_bytes(&mut salt);
     salt
 }
 
 #[cfg(test)]
 mod tests {
-    use std::ops::Deref as _;
-
     use super::*;
     use crate::crypto::derive_key;
     use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 
     #[test]
-    pub fn derive_seal_key_deterministic() {
+    fn derive_seal_key_deterministic() {
         static PASSWORD: &[u8] = b"password";
         let password = SafeCell::new(PASSWORD.to_vec());
         let password2 = SafeCell::new(PASSWORD.to_vec());
@@ -75,25 +71,24 @@ mod tests {
         let key1_reader = key1.0.read();
         let key2_reader = key2.0.read();
 
-        assert_eq!(key1_reader.deref(), key2_reader.deref());
+        assert_eq!(&*key1_reader, &*key2_reader);
     }
 
     #[test]
-    pub fn successful_derive() {
+    fn successful_derive() {
         static PASSWORD: &[u8] = b"password";
         let password = SafeCell::new(PASSWORD.to_vec());
         let salt = generate_salt();
 
         let mut key = derive_key(password, &salt);
         let key_reader = key.0.read();
-        let key_ref = key_reader.deref();
 
-        assert_ne!(key_ref.as_slice(), &[0u8; 32][..]);
+        assert_ne!(key_reader.as_slice(), &[0u8; 32][..]);
     }
 
     #[test]
     // We should fuzz this
-    pub fn test_nonce_increment() {
+    pub fn nonce_increment() {
         let mut nonce = Nonce([0u8; NONCE_LENGTH]);
         nonce.increment();
 

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

@@ -1,32 +1,29 @@
-use crate::actors::keyholder;
-use arbiter_crypto::hashing::Hashable;
-use hmac::Hmac;
-use sha2::Sha256;
-
-use diesel::{ExpressionMethods as _, QueryDsl, dsl::insert_into, sqlite::Sqlite};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::{actor::ActorRef, error::SendError};
-use sha2::Digest as _;
-
 use crate::{
-    actors::keyholder::{KeyHolder, SignIntegrity, VerifyIntegrity},
+    actors::vault::{self, GetState, SignIntegrity, Vault, VerifyIntegrity},
     db::{
         self,
         models::{IntegrityEnvelope, NewIntegrityEnvelope},
         schema::integrity_envelope,
     },
 };
+use arbiter_crypto::hashing::Hashable;
+
+use diesel::{ExpressionMethods as _, QueryDsl, dsl::insert_into, sqlite::Sqlite};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use hmac::Hmac;
+use kameo::{actor::ActorRef, error::SendError};
+use sha2::{Digest as _, Sha256};
 
 #[derive(Debug, thiserror::Error)]
 pub enum Error {
     #[error("Database error: {0}")]
     Database(#[from] db::DatabaseError),
 
-    #[error("KeyHolder error: {0}")]
-    Keyholder(#[from] keyholder::Error),
+    #[error("Vault error: {0}")]
+    Vault(#[from] vault::Error),
 
-    #[error("KeyHolder mailbox error")]
-    KeyholderSend,
+    #[error("Vault mailbox error")]
+    VaultSend,
 
     #[error("Integrity envelope is missing for entity {entity_kind}")]
     MissingEnvelope { entity_kind: &'static str },
@@ -67,6 +64,11 @@ fn payload_hash(payload: &impl Hashable) -> [u8; 32] {
 }
 
 fn push_len_prefixed(out: &mut Vec<u8>, bytes: &[u8]) {
+    #[expect(
+        clippy::cast_possible_truncation,
+        clippy::as_conversions,
+        reason = "fixme! #85"
+    )]
     out.extend_from_slice(&(bytes.len() as u32).to_be_bytes());
     out.extend_from_slice(bytes);
 }
@@ -103,7 +105,7 @@ impl IntoId for &'_ [u8] {
 
 pub async fn sign_entity<E: Integrable>(
     conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
     entity: &E,
     entity_id: impl IntoId,
 ) -> Result<(), Error> {
@@ -113,12 +115,13 @@ pub async fn sign_entity<E: Integrable>(
 
     let mac_input = build_mac_input(E::KIND, &entity_id, E::VERSION, &payload_hash);
 
-    let (key_version, mac) = keyholder
+    let (key_version, mac) =
+        vault
             .ask(SignIntegrity { mac_input })
             .await
             .map_err(|err| match err {
-            kameo::error::SendError::HandlerError(inner) => Error::Keyholder(inner),
-            _ => Error::KeyholderSend,
+                SendError::HandlerError(inner) => Error::Vault(inner),
+                _ => Error::VaultSend,
             })?;
 
     insert_into(integrity_envelope::table)
@@ -127,7 +130,7 @@ pub async fn sign_entity<E: Integrable>(
             entity_id,
             payload_version: E::VERSION,
             key_version,
-            mac: mac.to_vec(),
+            mac: mac.clone(),
         })
         .on_conflict((
             integrity_envelope::entity_id,
@@ -148,7 +151,7 @@ pub async fn sign_entity<E: Integrable>(
 
 pub async fn verify_entity<E: Integrable>(
     conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
     entity: &E,
     entity_id: impl IntoId,
 ) -> Result<AttestationStatus, Error> {
@@ -176,7 +179,7 @@ pub async fn verify_entity<E: Integrable>(
     let payload_hash = payload_hash(&entity);
     let mac_input = build_mac_input(E::KIND, &entity_id, envelope.payload_version, &payload_hash);
 
-    let result = keyholder
+    let result = vault
         .ask(VerifyIntegrity {
             mac_input,
             expected_mac: envelope.mac,
@@ -189,11 +192,14 @@ pub async fn verify_entity<E: Integrable>(
         Ok(false) => Err(Error::MacMismatch {
             entity_kind: E::KIND,
         }),
-        Err(SendError::HandlerError(keyholder::Error::NotBootstrapped)) => {
-            Ok(AttestationStatus::Unavailable)
+        Err(SendError::HandlerError(vault::Error::Sealed)) => Ok(AttestationStatus::Unavailable),
+        Err(_) => Err(Error::VaultSend),
     }
-        Err(_) => Err(Error::KeyholderSend),
 }
+
+pub async fn is_signing_available(vault: &ActorRef<Vault>) -> Result<bool, Error> {
+    let state = vault.ask(GetState).await.map_err(|_| Error::VaultSend)?;
+    Ok(matches!(state, vault::VaultState::Unsealed))
 }
 
 #[cfg(test)]
@@ -203,7 +209,10 @@ mod tests {
     use kameo::{actor::ActorRef, prelude::Spawn};
 
     use crate::{
-        actors::keyholder::{Bootstrap, KeyHolder},
+        actors::{
+            GlobalActors,
+            vault::{Bootstrap, Vault},
+        },
         db::{self, schema},
     };
     use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
@@ -218,8 +227,12 @@ mod tests {
         const KIND: &'static str = "dummy_entity";
     }
 
-    async fn bootstrapped_keyholder(db: &db::DatabasePool) -> ActorRef<KeyHolder> {
-        let actor = KeyHolder::spawn(KeyHolder::new(db.clone()).await.unwrap());
+    async fn bootstrapped_vault(db: &db::DatabasePool) -> ActorRef<Vault> {
+        let actor = Vault::spawn(
+            Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+                .await
+                .unwrap(),
+        );
         actor
             .ask(Bootstrap {
                 seal_key_raw: SafeCell::new(b"integrity-test-seal-key".to_vec()),
@@ -231,18 +244,18 @@ mod tests {
 
     #[tokio::test]
     async fn sign_writes_envelope_and_verify_passes() {
-        let db = db::create_test_pool().await;
-        let keyholder = bootstrapped_keyholder(&db).await;
-        let mut conn = db.get().await.unwrap();
-
         const ENTITY_ID: &[u8] = b"entity-id-7";
 
+        let db = db::create_test_pool().await;
+        let vault = bootstrapped_vault(&db).await;
+        let mut conn = db.get().await.unwrap();
+
         let entity = DummyEntity {
             payload_version: 1,
             payload: b"payload-v1".to_vec(),
         };
 
-        sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
             .await
             .unwrap();
 
@@ -255,25 +268,25 @@ mod tests {
             .unwrap();
 
         assert_eq!(count, 1, "envelope row must be created exactly once");
-        verify_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        verify_entity(&mut conn, &vault, &entity, ENTITY_ID)
             .await
             .unwrap();
     }
 
     #[tokio::test]
     async fn tampered_mac_fails_verification() {
-        let db = db::create_test_pool().await;
-        let keyholder = bootstrapped_keyholder(&db).await;
-        let mut conn = db.get().await.unwrap();
-
         const ENTITY_ID: &[u8] = b"entity-id-11";
 
+        let db = db::create_test_pool().await;
+        let vault = bootstrapped_vault(&db).await;
+        let mut conn = db.get().await.unwrap();
+
         let entity = DummyEntity {
             payload_version: 1,
             payload: b"payload-v1".to_vec(),
         };
 
-        sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
             .await
             .unwrap();
 
@@ -285,7 +298,7 @@ mod tests {
             .await
             .unwrap();
 
-        let err = verify_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        let err = verify_entity(&mut conn, &vault, &entity, ENTITY_ID)
             .await
             .unwrap_err();
         assert!(matches!(err, Error::MacMismatch { .. }));
@@ -293,18 +306,18 @@ mod tests {
 
     #[tokio::test]
     async fn changed_payload_fails_verification() {
-        let db = db::create_test_pool().await;
-        let keyholder = bootstrapped_keyholder(&db).await;
-        let mut conn = db.get().await.unwrap();
-
         const ENTITY_ID: &[u8] = b"entity-id-21";
 
+        let db = db::create_test_pool().await;
+        let vault = bootstrapped_vault(&db).await;
+        let mut conn = db.get().await.unwrap();
+
         let entity = DummyEntity {
             payload_version: 1,
             payload: b"payload-v1".to_vec(),
         };
 
-        sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
             .await
             .unwrap();
 
@@ -313,7 +326,7 @@ mod tests {
             ..entity
         };
 
-        let err = verify_entity(&mut conn, &keyholder, &tampered, ENTITY_ID)
+        let err = verify_entity(&mut conn, &vault, &tampered, ENTITY_ID)
             .await
             .unwrap_err();
         assert!(matches!(err, Error::MacMismatch { .. }));

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

@@ -1,4 +1,5 @@
-use std::ops::Deref as _;
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use encryption::v1::{Nonce, Salt};
 
 use argon2::{Algorithm, Argon2};
 use chacha20poly1305::{
@@ -10,13 +11,9 @@ use rand::{
     rngs::{StdRng, SysRng},
 };
 
-use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
-
 pub mod encryption;
 pub mod integrity;
 
-use encryption::v1::{Nonce, Salt};
-
 pub struct KeyCell(pub SafeCell<Key>);
 impl From<SafeCell<Key>> for KeyCell {
     fn from(value: SafeCell<Key>) -> Self {
@@ -41,11 +38,8 @@ impl TryFrom<SafeCell<Vec<u8>>> for KeyCell {
 impl KeyCell {
     pub fn new_secure_random() -> Self {
         let key = SafeCell::new_inline(|key_buffer: &mut Key| {
-            #[allow(
-                clippy::unwrap_used,
-                reason = "Rng failure is unrecoverable and should panic"
-            )]
-            let mut rng = StdRng::try_from_rng(&mut SysRng).unwrap();
+            let mut rng = StdRng::try_from_rng(&mut SysRng)
+                .expect("Rng failure is unrecoverable and should panic");
             rng.fill_bytes(key_buffer);
         });
 
@@ -59,8 +53,7 @@ impl KeyCell {
         mut buffer: impl AsMut<Vec<u8>>,
     ) -> Result<(), Error> {
         let key_reader = self.0.read();
-        let key_ref = key_reader.deref();
-        let cipher = XChaCha20Poly1305::new(key_ref);
+        let cipher = XChaCha20Poly1305::new(&key_reader);
         let nonce = XNonce::from_slice(nonce.0.as_ref());
         let buffer = buffer.as_mut();
         cipher.encrypt_in_place(nonce, associated_data, buffer)
@@ -72,8 +65,7 @@ impl KeyCell {
         buffer: &mut SafeCell<Vec<u8>>,
     ) -> Result<(), Error> {
         let key_reader = self.0.read();
-        let key_ref = key_reader.deref();
-        let cipher = XChaCha20Poly1305::new(key_ref);
+        let cipher = XChaCha20Poly1305::new(&key_reader);
         let nonce = XNonce::from_slice(nonce.0.as_ref());
         let mut buffer = buffer.write();
         let buffer: &mut Vec<u8> = buffer.as_mut();
@@ -87,8 +79,7 @@ impl KeyCell {
         plaintext: impl AsRef<[u8]>,
     ) -> Result<Vec<u8>, Error> {
         let key_reader = self.0.read();
-        let key_ref = key_reader.deref();
-        let mut cipher = XChaCha20Poly1305::new(key_ref);
+        let mut cipher = XChaCha20Poly1305::new(&key_reader);
         let nonce = XNonce::from_slice(nonce.0.as_ref());
 
         let ciphertext = cipher.encrypt(
@@ -116,20 +107,15 @@ pub fn derive_key(mut password: SafeCell<Vec<u8>>, salt: &Salt) -> KeyCell {
         }
     };
 
-    #[allow(clippy::unwrap_used)]
     let hasher = Argon2::new(Algorithm::Argon2id, argon2::Version::V0x13, params);
     let mut key = SafeCell::new(Key::default());
     password.read_inline(|password_source| {
         let mut key_buffer = key.write();
         let key_buffer: &mut [u8] = key_buffer.as_mut();
 
-        #[allow(
-            clippy::unwrap_used,
-            reason = "Better fail completely than return a weak key"
-        )]
         hasher
-            .hash_password_into(password_source.deref(), salt, key_buffer)
-            .unwrap();
+            .hash_password_into(password_source, salt, key_buffer)
+            .expect("Better fail completely than return a weak key");
     });
 
     key.into()
@@ -144,7 +130,7 @@ mod tests {
     use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 
     #[test]
-    pub fn encrypt_decrypt() {
+    fn encrypt_decrypt() {
         static PASSWORD: &[u8] = b"password";
         let password = SafeCell::new(PASSWORD.to_vec());
         let salt = generate_salt();

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

@@ -5,7 +5,6 @@ use diesel_async::{
     sync_connection_wrapper::SyncConnectionWrapper,
 };
 use diesel_migrations::{EmbeddedMigrations, MigrationHarness, embed_migrations};
-
 use thiserror::Error;
 use tracing::info;
 
@@ -23,14 +22,14 @@ const MIGRATIONS: EmbeddedMigrations = embed_migrations!("migrations");
 
 #[derive(Error, Debug)]
 pub enum DatabaseSetupError {
-    #[error("Failed to determine home directory")]
-    HomeDir(std::io::Error),
+    #[error(transparent)]
+    ConcurrencySetup(diesel::result::Error),
 
     #[error(transparent)]
     Connection(diesel::ConnectionError),
 
-    #[error(transparent)]
-    ConcurrencySetup(diesel::result::Error),
+    #[error("Failed to determine home directory")]
+    HomeDir(std::io::Error),
 
     #[error(transparent)]
     Migration(Box<dyn std::error::Error + Send + Sync>),
@@ -41,10 +40,11 @@ pub enum DatabaseSetupError {
 
 #[derive(Error, Debug)]
 pub enum DatabaseError {
-    #[error("Database connection error")]
-    Pool(#[from] PoolError),
     #[error("Database query error")]
     Connection(#[from] diesel::result::Error),
+
+    #[error("Database connection error")]
+    Pool(#[from] PoolError),
 }
 
 #[tracing::instrument(level = "info")]
@@ -93,13 +93,16 @@ fn initialize_database(url: &str) -> Result<(), DatabaseSetupError> {
 }
 
 #[tracing::instrument(level = "info")]
+/// Creates a connection pool for the `SQLite` database.
+///
+/// # Panics
+/// Panics if the database path is not valid UTF-8.
 pub async fn create_pool(url: Option<&str>) -> Result<DatabasePool, DatabaseSetupError> {
     let database_url = url.map(String::from).unwrap_or(
-        #[allow(clippy::expect_used)]
         database_path()?
             .to_str()
             .expect("database path is not valid UTF-8")
-            .to_string(),
+            .to_owned(),
     );
 
     initialize_database(&database_url)?;
@@ -134,19 +137,19 @@ pub async fn create_pool(url: Option<&str>) -> Result<DatabasePool, DatabaseSetu
 }
 
 #[mutants::skip]
+#[expect(clippy::missing_panics_doc, reason = "Tests oriented function")]
+/// Creates a test database pool with a temporary `SQLite` database file.
 pub async fn create_test_pool() -> DatabasePool {
     use rand::distr::{Alphanumeric, SampleString as _};
 
     let tempfile_name = Alphanumeric.sample_string(&mut rand::rng(), 16);
 
     let file = std::env::temp_dir().join(tempfile_name);
-    #[allow(clippy::expect_used)]
     let url = file
         .to_str()
         .expect("temp file path is not valid UTF-8")
-        .to_string();
+        .to_owned();
 
-    #[allow(clippy::expect_used)]
     create_pool(Some(&url))
         .await
         .expect("Failed to create test database pool")

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

@@ -1,13 +1,14 @@
-#![allow(unused)]
-#![allow(clippy::all)]
-
+#![allow(
+    clippy::duplicated_attributes,
+    reason = "restructed's #[view] causes false positives"
+)]
 use crate::db::schema::{
     self, aead_encrypted, arbiter_settings, evm_basic_grant, evm_ether_transfer_grant,
     evm_ether_transfer_grant_target, evm_ether_transfer_limit, evm_token_transfer_grant,
     evm_token_transfer_log, evm_token_transfer_volume_limit, evm_transaction_log, evm_wallet,
     integrity_envelope, root_key_history, tls_history,
 };
-use chrono::{DateTime, Utc};
+
 use diesel::{prelude::*, sqlite::Sqlite};
 use restructed::Models;
 
@@ -27,16 +28,16 @@ pub mod types {
     pub struct SqliteTimestamp(pub DateTime<Utc>);
     impl SqliteTimestamp {
         pub fn now() -> Self {
-            SqliteTimestamp(Utc::now())
+            Self(Utc::now())
         }
     }
 
-    impl From<chrono::DateTime<Utc>> for SqliteTimestamp {
-        fn from(dt: chrono::DateTime<Utc>) -> Self {
-            SqliteTimestamp(dt)
+    impl From<DateTime<Utc>> for SqliteTimestamp {
+        fn from(dt: DateTime<Utc>) -> Self {
+            Self(dt)
         }
     }
-    impl From<SqliteTimestamp> for chrono::DateTime<Utc> {
+    impl From<SqliteTimestamp> for DateTime<Utc> {
         fn from(ts: SqliteTimestamp) -> Self {
             ts.0
         }
@@ -47,6 +48,11 @@ pub mod types {
             &'b self,
             out: &mut diesel::serialize::Output<'b, '_, Sqlite>,
         ) -> diesel::serialize::Result {
+            #[expect(
+                clippy::cast_possible_truncation,
+                clippy::as_conversions,
+                reason = "fixme! #84; this will break up in 2038 :3"
+            )]
             let unix_timestamp = self.0.timestamp() as i32;
             out.set_value(unix_timestamp);
             Ok(IsNull::No)
@@ -69,7 +75,47 @@ pub mod types {
             let datetime =
                 DateTime::from_timestamp(unix_timestamp, 0).ok_or("Timestamp is out of bounds")?;
 
-            Ok(SqliteTimestamp(datetime))
+            Ok(Self(datetime))
+        }
+    }
+
+    #[derive(Debug, FromSqlRow, AsExpression, Clone)]
+    #[diesel(sql_type = Integer)]
+    #[repr(transparent)] // hint compiler to optimize the wrapper struct away
+    pub struct ChainId(pub i32);
+
+    #[expect(
+        clippy::cast_sign_loss,
+        clippy::cast_possible_truncation,
+        clippy::as_conversions,
+        reason = "safe because chain_id is stored as i32 but is guaranteed to be a valid ChainId by the API when creating grants"
+    )]
+    const _: () = {
+        impl From<ChainId> for alloy::primitives::ChainId {
+            fn from(chain_id: ChainId) -> Self {
+                chain_id.0 as Self
+            }
+        }
+        impl From<alloy::primitives::ChainId> for ChainId {
+            fn from(chain_id: alloy::primitives::ChainId) -> Self {
+                Self(chain_id as _)
+            }
+        }
+    };
+
+    impl FromSql<Integer, Sqlite> for ChainId {
+        fn from_sql(
+            bytes: <Sqlite as diesel::backend::Backend>::RawValue<'_>,
+        ) -> diesel::deserialize::Result<Self> {
+            FromSql::<Integer, Sqlite>::from_sql(bytes).map(Self)
+        }
+    }
+    impl ToSql<Integer, Sqlite> for ChainId {
+        fn to_sql<'b>(
+            &'b self,
+            out: &mut diesel::serialize::Output<'b, '_, Sqlite>,
+        ) -> diesel::serialize::Result {
+            ToSql::<Integer, Sqlite>::to_sql(&self.0, out)
         }
     }
 }
@@ -195,7 +241,6 @@ pub struct ProgramClientMetadataHistory {
 #[diesel(table_name = schema::program_client, check_for_backend(Sqlite))]
 pub struct ProgramClient {
     pub id: i32,
-    pub nonce: i32,
     pub public_key: Vec<u8>,
     pub metadata_id: i32,
     pub created_at: SqliteTimestamp,
@@ -206,7 +251,6 @@ pub struct ProgramClient {
 #[diesel(table_name = schema::useragent_client, check_for_backend(Sqlite))]
 pub struct UseragentClient {
     pub id: i32,
-    pub nonce: i32,
     pub public_key: Vec<u8>,
     pub created_at: SqliteTimestamp,
     pub updated_at: SqliteTimestamp,
@@ -237,7 +281,7 @@ pub struct EvmEtherTransferLimit {
 pub struct EvmBasicGrant {
     pub id: i32,
     pub wallet_access_id: i32, // references evm_wallet_access.id
-    pub chain_id: i32,
+    pub chain_id: ChainId,
     pub valid_from: Option<SqliteTimestamp>,
     pub valid_until: Option<SqliteTimestamp>,
     pub max_gas_fee_per_gas: Option<Vec<u8>>,
@@ -260,7 +304,7 @@ pub struct EvmTransactionLog {
     pub id: i32,
     pub grant_id: i32,
     pub wallet_access_id: i32,
-    pub chain_id: i32,
+    pub chain_id: ChainId,
     pub eth_value: Vec<u8>,
     pub signed_at: SqliteTimestamp,
 }
@@ -335,7 +379,7 @@ pub struct EvmTokenTransferLog {
     pub id: i32,
     pub grant_id: i32,
     pub log_id: i32,
-    pub chain_id: i32,
+    pub chain_id: ChainId,
     pub token_contract: Vec<u8>,
     pub recipient_address: Vec<u8>,
     pub value: Vec<u8>,

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

@@ -155,7 +155,6 @@ diesel::table! {
 diesel::table! {
     program_client (id) {
         id -> Integer,
-        nonce -> Integer,
         public_key -> Binary,
         metadata_id -> Integer,
         created_at -> Integer,
@@ -189,9 +188,7 @@ diesel::table! {
 diesel::table! {
     useragent_client (id) {
         id -> Integer,
-        nonce -> Integer,
         public_key -> Binary,
-        key_type -> Integer,
         created_at -> Integer,
         updated_at -> Integer,
     }

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

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

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

@@ -1,17 +1,5 @@
-pub mod abi;
-pub mod safe_signer;
-
-use alloy::{
-    consensus::TxEip1559,
-    primitives::{TxKind, U256},
-};
-use chrono::Utc;
-use diesel::{ExpressionMethods as _, QueryDsl as _, QueryResult, insert_into, sqlite::Sqlite};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::actor::ActorRef;
-
 use crate::{
-    actors::keyholder::KeyHolder,
+    actors::vault::Vault,
     crypto::integrity,
     db::{
         self, DatabaseError,
@@ -27,6 +15,18 @@ use crate::{
     },
 };
 
+use alloy::{
+    consensus::TxEip1559,
+    primitives::{TxKind, U256},
+};
+use chrono::Utc;
+use diesel::{ExpressionMethods as _, QueryDsl as _, QueryResult, insert_into, sqlite::Sqlite};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use kameo::actor::ActorRef;
+
+pub mod abi;
+pub mod safe_signer;
+
 pub mod policies;
 mod utils;
 
@@ -34,7 +34,7 @@ mod utils;
 #[derive(Debug, thiserror::Error)]
 pub enum PolicyError {
     #[error("Database error")]
-    Database(#[from] crate::db::DatabaseError),
+    Database(#[from] DatabaseError),
     #[error("Transaction violates policy: {0:?}")]
     Violations(Vec<EvalViolation>),
     #[error("No matching grant found")]
@@ -66,7 +66,7 @@ pub enum AnalyzeError {
 #[derive(Debug, thiserror::Error)]
 pub enum ListError {
     #[error("Database error")]
-    Database(#[from] crate::db::DatabaseError),
+    Database(#[from] DatabaseError),
 
     #[error("Integrity verification failed for grant")]
     Integrity(#[from] integrity::Error),
@@ -127,7 +127,7 @@ async fn check_shared_constraints(
             .get_result(conn)
             .await?;
 
-        if count >= rate_limit.count as i64 {
+        if count >= rate_limit.count.into() {
             violations.push(EvalViolation::RateLimitExceeded);
         }
     }
@@ -138,7 +138,7 @@ async fn check_shared_constraints(
 // Supporting only EIP-1559 transactions for now, but we can easily extend this to support legacy transactions if needed
 pub struct Engine {
     db: db::DatabasePool,
-    keyholder: ActorRef<KeyHolder>,
+    vault: ActorRef<Vault>,
 }
 
 impl Engine {
@@ -158,7 +158,7 @@ impl Engine {
             .map_err(DatabaseError::from)?
             .ok_or(PolicyError::NoMatchingGrant)?;
 
-        integrity::verify_entity(&mut conn, &self.keyholder, &grant.settings, grant.id).await?;
+        integrity::verify_entity(&mut conn, &self.vault, &grant.settings, grant.id).await?;
 
         let mut violations = check_shared_constraints(
             &context,
@@ -185,7 +185,7 @@ impl Engine {
                         .values(&NewEvmTransactionLog {
                             grant_id: grant.common_settings_id,
                             wallet_access_id: context.target.id,
-                            chain_id: context.chain as i32,
+                            chain_id: context.chain.into(),
                             eth_value: utils::u256_to_bytes(context.value).to_vec(),
                             signed_at: Utc::now().into(),
                         })
@@ -207,8 +207,8 @@ impl Engine {
 }
 
 impl Engine {
-    pub fn new(db: db::DatabasePool, keyholder: ActorRef<KeyHolder>) -> Self {
-        Self { db, keyholder }
+    pub const fn new(db: db::DatabasePool, vault: ActorRef<Vault>) -> Self {
+        Self { db, vault }
     }
 
     pub async fn create_grant<P: Policy>(
@@ -219,16 +219,22 @@ impl Engine {
         P::Settings: Clone,
     {
         let mut conn = self.db.get().await?;
-        let keyholder = self.keyholder.clone();
+        let vault = self.vault.clone();
 
         let id = conn
             .transaction(|conn| {
                 Box::pin(async move {
                     use schema::evm_basic_grant;
 
+                    #[expect(
+                        clippy::cast_possible_truncation,
+                        clippy::cast_possible_wrap,
+                        clippy::as_conversions,
+                        reason = "fixme! #86"
+                    )]
                     let basic_grant: EvmBasicGrant = insert_into(evm_basic_grant::table)
                         .values(&NewEvmBasicGrant {
-                            chain_id: full_grant.shared.chain as i32,
+                            chain_id: full_grant.shared.chain.into(),
                             wallet_access_id: full_grant.shared.wallet_access_id,
                             valid_from: full_grant.shared.valid_from.map(SqliteTimestamp),
                             valid_until: full_grant.shared.valid_until.map(SqliteTimestamp),
@@ -258,7 +264,7 @@ impl Engine {
 
                     P::create_grant(&basic_grant, &full_grant.specific, conn).await?;
 
-                    integrity::sign_entity(conn, &keyholder, &full_grant, basic_grant.id)
+                    integrity::sign_entity(conn, &vault, &full_grant, basic_grant.id)
                         .await
                         .map_err(|_| diesel::result::Error::RollbackTransaction)?;
 
@@ -283,7 +289,7 @@ impl Engine {
 
         // Verify integrity of all grants before returning any results
         for grant in &all_grants {
-            integrity::verify_entity(conn, &self.keyholder, &grant.settings, grant.id).await?;
+            integrity::verify_entity(conn, &self.vault, &grant.settings, grant.id).await?;
         }
 
         Ok(all_grants.into_iter().map(|g| Grant {
@@ -313,7 +319,7 @@ impl Engine {
         let TxKind::Call(to) = transaction.to else {
             return Err(VetError::ContractCreationNotSupported);
         };
-        let context = policies::EvalContext {
+        let context = EvalContext {
             target,
             chain: transaction.chain_id,
             to,
@@ -404,10 +410,16 @@ mod tests {
         conn: &mut DatabaseConnection,
         shared: &SharedGrantSettings,
     ) -> EvmBasicGrant {
+        #[expect(
+            clippy::cast_possible_truncation,
+            clippy::cast_possible_wrap,
+            clippy::as_conversions,
+            reason = "fixme! #86"
+        )]
         insert_into(evm_basic_grant::table)
             .values(NewEvmBasicGrant {
                 wallet_access_id: shared.wallet_access_id,
-                chain_id: shared.chain as i32,
+                chain_id: shared.chain.into(),
                 valid_from: shared.valid_from.map(SqliteTimestamp),
                 valid_until: shared.valid_until.map(SqliteTimestamp),
                 max_gas_fee_per_gas: shared
@@ -571,7 +583,7 @@ mod tests {
             .values(NewEvmTransactionLog {
                 grant_id: basic_grant.id,
                 wallet_access_id: WALLET_ACCESS_ID,
-                chain_id: CHAIN_ID as i32,
+                chain_id: CHAIN_ID.into(),
                 eth_value: super::utils::u256_to_bytes(U256::ZERO).to_vec(),
                 signed_at: SqliteTimestamp(Utc::now()),
             })

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

@@ -1,4 +1,8 @@
-use std::fmt::Display;
+use crate::{
+    crypto::integrity::v1::Integrable,
+    db::models::{EvmBasicGrant, EvmWalletAccess},
+    evm::utils,
+};
 
 use alloy::primitives::{Address, Bytes, ChainId, U256};
 use chrono::{DateTime, Duration, Utc};
@@ -6,15 +10,9 @@ use diesel::{
     ExpressionMethods as _, QueryDsl, SelectableHelper, result::QueryResult, sqlite::Sqlite,
 };
 use diesel_async::{AsyncConnection, RunQueryDsl};
-
+use std::fmt::Display;
 use thiserror::Error;
 
-use crate::{
-    crypto::integrity::v1::Integrable,
-    db::models::{self, EvmBasicGrant, EvmWalletAccess},
-    evm::utils,
-};
-
 pub mod ether_transfer;
 pub mod token_transfers;
 
@@ -87,10 +85,10 @@ pub trait Policy: Sized {
 
     // Create a new grant in the database based on the provided grant details, and return its ID
     fn create_grant(
-        basic: &models::EvmBasicGrant,
+        basic: &EvmBasicGrant,
         grant: &Self::Settings,
         conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    ) -> impl std::future::Future<Output = QueryResult<DatabaseID>> + Send;
+    ) -> impl Future<Output = QueryResult<DatabaseID>> + Send;
 
     // Try to find an existing grant that matches the transaction context, and return its details if found
     // Additionally, return ID of basic grant for shared-logic checks like rate limits and validity periods
@@ -157,7 +155,7 @@ impl SharedGrantSettings {
     pub(crate) fn try_from_model(model: EvmBasicGrant) -> QueryResult<Self> {
         Ok(Self {
             wallet_access_id: model.wallet_access_id,
-            chain: model.chain_id as u64, // safe because chain_id is stored as i32 but is guaranteed to be a valid ChainId by the API when creating grants
+            chain: model.chain_id.into(),
             valid_from: model.valid_from.map(Into::into),
             valid_until: model.valid_until.map(Into::into),
             max_gas_fee_per_gas: model
@@ -168,10 +166,11 @@ impl SharedGrantSettings {
                 .max_priority_fee_per_gas
                 .map(|b| utils::try_bytes_to_u256(&b))
                 .transpose()?,
+            #[expect(clippy::cast_sign_loss, clippy::as_conversions, reason = "fixme! #86")]
             rate_limit: match (model.rate_limit_count, model.rate_limit_window_secs) {
                 (Some(count), Some(window_secs)) => Some(TransactionRateLimit {
                     count: count as u32,
-                    window: Duration::seconds(window_secs as i64),
+                    window: Duration::seconds(window_secs.into()),
                 }),
                 _ => None,
             },
@@ -181,7 +180,7 @@ impl SharedGrantSettings {
     pub async fn query_by_id(
         conn: &mut impl AsyncConnection<Backend = Sqlite>,
         id: i32,
-    ) -> diesel::result::QueryResult<Self> {
+    ) -> QueryResult<Self> {
         use crate::db::schema::evm_basic_grant;
 
         let basic_grant: EvmBasicGrant = evm_basic_grant::table

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

@@ -1,30 +1,32 @@
-use std::collections::HashMap;
-use std::fmt::Display;
-
-use alloy::primitives::{Address, U256};
-use chrono::{DateTime, Duration, Utc};
-use diesel::dsl::{auto_type, insert_into};
-use diesel::sqlite::Sqlite;
-use diesel::{ExpressionMethods, JoinOnDsl, prelude::*};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-
-use crate::crypto::integrity::v1::Integrable;
-use crate::db::models::{
+use super::{DatabaseID, EvalContext, EvalViolation};
+use crate::{
+    crypto::integrity::v1::Integrable,
+    db::models::{
         EvmBasicGrant, EvmEtherTransferGrant, EvmEtherTransferGrantTarget, EvmEtherTransferLimit,
         NewEvmEtherTransferLimit, SqliteTimestamp,
-};
-use crate::db::schema::{evm_basic_grant, evm_ether_transfer_limit, evm_transaction_log};
-use crate::evm::policies::{
-    CombinedSettings, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning, VolumeRateLimit,
-};
-use crate::{
+    },
+    db::schema::{evm_basic_grant, evm_ether_transfer_limit, evm_transaction_log},
     db::{
-        models::{self, NewEvmEtherTransferGrant, NewEvmEtherTransferGrantTarget},
+        models::{NewEvmEtherTransferGrant, NewEvmEtherTransferGrantTarget},
         schema::{evm_ether_transfer_grant, evm_ether_transfer_grant_target},
     },
+    evm::policies::{
+        CombinedSettings, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
+        VolumeRateLimit,
+    },
     evm::{policies::Policy, utils},
 };
 
+use alloy::primitives::{Address, U256};
+use chrono::{DateTime, Duration, Utc};
+use diesel::{
+    dsl::{auto_type, insert_into},
+    prelude::*,
+    sqlite::Sqlite,
+};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use std::{collections::HashMap, fmt::Display};
+
 #[auto_type]
 fn grant_join() -> _ {
     evm_ether_transfer_grant::table.inner_join(
@@ -32,8 +34,6 @@ fn grant_join() -> _ {
     )
 }
 
-use super::{DatabaseID, EvalContext, EvalViolation};
-
 // Plain ether transfer
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Meaning {
@@ -46,8 +46,8 @@ impl Display for Meaning {
     }
 }
 impl From<Meaning> for SpecificMeaning {
-    fn from(val: Meaning) -> SpecificMeaning {
-        SpecificMeaning::EtherTransfer(val)
+    fn from(val: Meaning) -> Self {
+        Self::EtherTransfer(val)
     }
 }
 
@@ -62,8 +62,8 @@ impl Integrable for Settings {
 }
 
 impl From<Settings> for SpecificGrant {
-    fn from(val: Settings) -> SpecificGrant {
-        SpecificGrant::EtherTransfer(val)
+    fn from(val: Settings) -> Self {
+        Self::EtherTransfer(val)
     }
 }
 
@@ -74,9 +74,7 @@ async fn query_relevant_past_transaction(
 ) -> QueryResult<Vec<(U256, DateTime<Utc>)>> {
     let past_transactions: Vec<(Vec<u8>, SqliteTimestamp)> = evm_transaction_log::table
         .filter(evm_transaction_log::grant_id.eq(grant_id))
-        .filter(
-            evm_transaction_log::signed_at.ge(SqliteTimestamp(chrono::Utc::now() - longest_window)),
-        )
+        .filter(evm_transaction_log::signed_at.ge(SqliteTimestamp(Utc::now() - longest_window)))
         .select((
             evm_transaction_log::eth_value,
             evm_transaction_log::signed_at,
@@ -103,7 +101,7 @@ async fn check_rate_limits(
 
     let past_transaction = query_relevant_past_transaction(grant.id, window, db).await?;
 
-    let window_start = chrono::Utc::now() - grant.settings.specific.limit.window;
+    let window_start = Utc::now() - grant.settings.specific.limit.window;
     let prospective_cumulative_volume: U256 = past_transaction
         .iter()
         .filter(|(_, timestamp)| timestamp >= &window_start)
@@ -153,10 +151,15 @@ impl Policy for EtherTransfer {
     }
 
     async fn create_grant(
-        basic: &models::EvmBasicGrant,
+        basic: &EvmBasicGrant,
         grant: &Self::Settings,
         conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    ) -> diesel::result::QueryResult<DatabaseID> {
+    ) -> QueryResult<DatabaseID> {
+        #[expect(
+            clippy::cast_possible_truncation,
+            clippy::as_conversions,
+            reason = "fixme! #86"
+        )]
         let limit_id: i32 = insert_into(evm_ether_transfer_limit::table)
             .values(NewEvmEtherTransferLimit {
                 window_secs: grant.limit.window.num_seconds() as i32,
@@ -191,7 +194,7 @@ impl Policy for EtherTransfer {
     async fn try_find_grant(
         context: &EvalContext,
         conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    ) -> diesel::result::QueryResult<Option<Grant<Self::Settings>>> {
+    ) -> QueryResult<Option<Grant<Self::Settings>>> {
         let target_bytes = context.to.to_vec();
 
         // Find a grant where:
@@ -245,7 +248,7 @@ impl Policy for EtherTransfer {
             limit: VolumeRateLimit {
                 max_volume: utils::try_bytes_to_u256(&limit.max_volume)
                     .map_err(|err| diesel::result::Error::DeserializationError(Box::new(err)))?,
-                window: chrono::Duration::seconds(limit.window_secs as i64),
+                window: Duration::seconds(limit.window_secs.into()),
             },
         };
 
@@ -265,7 +268,7 @@ impl Policy for EtherTransfer {
         _log_id: i32,
         _grant: &Grant<Self::Settings>,
         _conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    ) -> diesel::result::QueryResult<()> {
+    ) -> QueryResult<()> {
         // Basic log is sufficient
 
         Ok(())
@@ -318,7 +321,7 @@ impl Policy for EtherTransfer {
             .map(|(basic, specific)| {
                 let targets: Vec<Address> = targets_by_grant
                     .get(&specific.id)
-                    .map(|v| v.as_slice())
+                    .map(Vec::as_slice)
                     .unwrap_or_default()
                     .iter()
                     .filter_map(|t| {
@@ -342,7 +345,7 @@ impl Policy for EtherTransfer {
                                 max_volume: utils::try_bytes_to_u256(&limit.max_volume).map_err(
                                     |e| diesel::result::Error::DeserializationError(Box::new(e)),
                                 )?,
-                                window: Duration::seconds(limit.window_secs as i64),
+                                window: Duration::seconds(limit.window_secs.into()),
                             },
                         },
                     },

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

@@ -1,27 +1,28 @@
-use alloy::primitives::{Address, Bytes, U256, address};
-use chrono::{Duration, Utc};
-use diesel::{SelectableHelper, insert_into};
-use diesel_async::RunQueryDsl;
-
-use crate::db::{
+use super::{EtherTransfer, Settings};
+use crate::{
+    db::{
         self, DatabaseConnection,
         models::{
             EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, NewEvmTransactionLog, SqliteTimestamp,
         },
         schema::{evm_basic_grant, evm_transaction_log},
-};
-use crate::evm::{
+    },
+    evm::{
         policies::{
             CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
             VolumeRateLimit,
         },
         utils,
+    },
 };
 
-use super::{EtherTransfer, Settings};
+use alloy::primitives::{Address, Bytes, U256, address};
+use chrono::{Duration, Utc};
+use diesel::{SelectableHelper, insert_into};
+use diesel_async::RunQueryDsl;
 
 const WALLET_ACCESS_ID: i32 = 1;
-const CHAIN_ID: u64 = 1;
+const CHAIN_ID: alloy::primitives::ChainId = 1;
 
 const ALLOWED: Address = address!("1111111111111111111111111111111111111111");
 const OTHER: Address = address!("2222222222222222222222222222222222222222");
@@ -47,7 +48,7 @@ async fn insert_basic(conn: &mut DatabaseConnection, revoked: bool) -> EvmBasicG
     insert_into(evm_basic_grant::table)
         .values(NewEvmBasicGrant {
             wallet_access_id: WALLET_ACCESS_ID,
-            chain_id: CHAIN_ID as i32,
+            chain_id: CHAIN_ID.into(),
             valid_from: None,
             valid_until: None,
             max_gas_fee_per_gas: None,
@@ -160,7 +161,7 @@ async fn evaluate_passes_when_volume_within_limit() {
         .values(NewEvmTransactionLog {
             grant_id,
             wallet_access_id: WALLET_ACCESS_ID,
-            chain_id: CHAIN_ID as i32,
+            chain_id: CHAIN_ID.into(),
             eth_value: utils::u256_to_bytes(U256::from(500u64)).to_vec(),
             signed_at: SqliteTimestamp(Utc::now()),
         })
@@ -202,7 +203,7 @@ async fn evaluate_rejects_volume_over_limit() {
         .values(NewEvmTransactionLog {
             grant_id,
             wallet_access_id: WALLET_ACCESS_ID,
-            chain_id: CHAIN_ID as i32,
+            chain_id: CHAIN_ID.into(),
             eth_value: utils::u256_to_bytes(U256::from(1_000u64)).to_vec(),
             signed_at: SqliteTimestamp(Utc::now()),
         })
@@ -245,7 +246,7 @@ async fn evaluate_passes_at_exactly_volume_limit() {
         .values(NewEvmTransactionLog {
             grant_id,
             wallet_access_id: WALLET_ACCESS_ID,
-            chain_id: CHAIN_ID as i32,
+            chain_id: CHAIN_ID.into(),
             eth_value: utils::u256_to_bytes(U256::from(900u64)).to_vec(),
             signed_at: SqliteTimestamp(Utc::now()),
         })

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

@@ -1,16 +1,4 @@
-use std::collections::HashMap;
-
-use crate::db::schema::{
-    evm_basic_grant, evm_token_transfer_grant, evm_token_transfer_log,
-    evm_token_transfer_volume_limit,
-};
-use crate::evm::{
-    abi::IERC20::transferCall,
-    policies::{
-        Grant, Policy, SharedGrantSettings, SpecificGrant, SpecificMeaning, VolumeRateLimit,
-    },
-    utils,
-};
+use super::{DatabaseID, EvalContext, EvalViolation};
 use crate::{
     crypto::integrity::Integrable,
     db::models::{
@@ -18,20 +6,33 @@ use crate::{
         NewEvmTokenTransferGrant, NewEvmTokenTransferLog, NewEvmTokenTransferVolumeLimit,
         SqliteTimestamp,
     },
+    db::schema::{
+        evm_basic_grant, evm_token_transfer_grant, evm_token_transfer_log,
+        evm_token_transfer_volume_limit,
+    },
     evm::policies::CombinedSettings,
+    evm::{
+        abi::IERC20::transferCall,
+        policies::{
+            Grant, Policy, SharedGrantSettings, SpecificGrant, SpecificMeaning, VolumeRateLimit,
+        },
+        utils,
+    },
 };
+use arbiter_tokens_registry::evm::nonfungible::{self, TokenInfo};
+
 use alloy::{
     primitives::{Address, U256},
     sol_types::SolCall,
 };
-use arbiter_tokens_registry::evm::nonfungible::{self, TokenInfo};
 use chrono::{DateTime, Duration, Utc};
-use diesel::dsl::{auto_type, insert_into};
-use diesel::sqlite::Sqlite;
-use diesel::{ExpressionMethods, prelude::*};
+use diesel::{
+    dsl::{auto_type, insert_into},
+    prelude::*,
+    sqlite::Sqlite,
+};
 use diesel_async::{AsyncConnection, RunQueryDsl};
-
-use super::{DatabaseID, EvalContext, EvalViolation};
+use std::collections::HashMap;
 
 #[auto_type]
 fn grant_join() -> _ {
@@ -56,8 +57,8 @@ impl std::fmt::Display for Meaning {
     }
 }
 impl From<Meaning> for SpecificMeaning {
-    fn from(val: Meaning) -> SpecificMeaning {
-        SpecificMeaning::TokenTransfer(val)
+    fn from(val: Meaning) -> Self {
+        Self::TokenTransfer(val)
     }
 }
 
@@ -73,8 +74,8 @@ impl Integrable for Settings {
 }
 
 impl From<Settings> for SpecificGrant {
-    fn from(val: Settings) -> SpecificGrant {
-        SpecificGrant::TokenTransfer(val)
+    fn from(val: Settings) -> Self {
+        Self::TokenTransfer(val)
     }
 }
 
@@ -85,10 +86,7 @@ async fn query_relevant_past_transfers(
 ) -> QueryResult<Vec<(U256, DateTime<Utc>)>> {
     let past_logs: Vec<(Vec<u8>, SqliteTimestamp)> = evm_token_transfer_log::table
         .filter(evm_token_transfer_log::grant_id.eq(grant_id))
-        .filter(
-            evm_token_transfer_log::created_at
-                .ge(SqliteTimestamp(chrono::Utc::now() - longest_window)),
-        )
+        .filter(evm_token_transfer_log::created_at.ge(SqliteTimestamp(Utc::now() - longest_window)))
         .select((
             evm_token_transfer_log::value,
             evm_token_transfer_log::created_at,
@@ -128,7 +126,7 @@ async fn check_volume_rate_limits(
     let past_transfers = query_relevant_past_transfers(grant.id, longest_window, db).await?;
 
     for limit in &grant.settings.specific.volume_limits {
-        let window_start = chrono::Utc::now() - limit.window;
+        let window_start = Utc::now() - limit.window;
         let prospective_cumulative_volume: U256 = past_transfers
             .iter()
             .filter(|(_, timestamp)| timestamp >= &window_start)
@@ -204,6 +202,11 @@ impl Policy for TokenTransfer {
             .await?;
 
         for limit in &grant.volume_limits {
+            #[expect(
+                clippy::cast_possible_truncation,
+                clippy::as_conversions,
+                reason = "fixme! #86"
+            )]
             insert_into(evm_token_transfer_volume_limit::table)
                 .values(NewEvmTokenTransferVolumeLimit {
                     grant_id,
@@ -253,7 +256,7 @@ impl Policy for TokenTransfer {
                     max_volume: utils::try_bytes_to_u256(&row.max_volume).map_err(|err| {
                         diesel::result::Error::DeserializationError(Box::new(err))
                     })?,
-                    window: Duration::seconds(row.window_secs as i64),
+                    window: Duration::seconds(row.window_secs.into()),
                 })
             })
             .collect::<QueryResult<Vec<_>>>()?;
@@ -303,7 +306,7 @@ impl Policy for TokenTransfer {
             .values(NewEvmTokenTransferLog {
                 grant_id: grant.id,
                 log_id,
-                chain_id: context.chain as i32,
+                chain_id: context.chain.into(),
                 token_contract: context.to.to_vec(),
                 recipient_address: meaning.to.to_vec(),
                 value: utils::u256_to_bytes(meaning.value).to_vec(),
@@ -352,7 +355,7 @@ impl Policy for TokenTransfer {
             .map(|(basic, specific)| {
                 let volume_limits: Vec<VolumeRateLimit> = limits_by_grant
                     .get(&specific.id)
-                    .map(|v| v.as_slice())
+                    .map(Vec::as_slice)
                     .unwrap_or_default()
                     .iter()
                     .map(|row| {
@@ -360,7 +363,7 @@ impl Policy for TokenTransfer {
                             max_volume: utils::try_bytes_to_u256(&row.max_volume).map_err(|e| {
                                 diesel::result::Error::DeserializationError(Box::new(e))
                             })?,
-                            window: Duration::seconds(row.window_secs as i64),
+                            window: Duration::seconds(row.window_secs.into()),
                         })
                     })
                     .collect::<QueryResult<Vec<_>>>()?;

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

@@ -1,24 +1,27 @@
-use alloy::primitives::{Address, Bytes, U256, address};
-use alloy::sol_types::SolCall;
-use chrono::{Duration, Utc};
-use diesel::{SelectableHelper, insert_into};
-use diesel_async::RunQueryDsl;
-
-use crate::db::{
+use super::{Settings, TokenTransfer};
+use crate::{
+    db::{
         self, DatabaseConnection,
         models::{EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, SqliteTimestamp},
         schema::evm_basic_grant,
-};
-use crate::evm::{
+    },
+    evm::{
         abi::IERC20::transferCall,
         policies::{
             CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
             VolumeRateLimit,
         },
         utils,
+    },
 };
 
-use super::{Settings, TokenTransfer};
+use alloy::{
+    primitives::{Address, Bytes, U256, address},
+    sol_types::SolCall,
+};
+use chrono::{Duration, Utc};
+use diesel::{SelectableHelper, insert_into};
+use diesel_async::RunQueryDsl;
 
 // DAI on Ethereum mainnet — present in the static token registry
 const CHAIN_ID: u64 = 1;
@@ -59,7 +62,7 @@ async fn insert_basic(conn: &mut DatabaseConnection, revoked: bool) -> EvmBasicG
     insert_into(evm_basic_grant::table)
         .values(NewEvmBasicGrant {
             wallet_access_id: WALLET_ACCESS_ID,
-            chain_id: CHAIN_ID as i32,
+            chain_id: CHAIN_ID.into(),
             valid_from: None,
             valid_until: None,
             max_gas_fee_per_gas: None,
@@ -238,12 +241,11 @@ async fn evaluate_passes_volume_at_exact_limit() {
         .unwrap();
 
     // Record a past transfer of 900, with current transfer 100 => exactly 1000 limit
-    use crate::db::{models::NewEvmTokenTransferLog, schema::evm_token_transfer_log};
-    insert_into(evm_token_transfer_log::table)
-        .values(NewEvmTokenTransferLog {
+    insert_into(db::schema::evm_token_transfer_log::table)
+        .values(db::models::NewEvmTokenTransferLog {
             grant_id,
             log_id: 0,
-            chain_id: CHAIN_ID as i32,
+            chain_id: CHAIN_ID.into(),
             token_contract: DAI.to_vec(),
             recipient_address: RECIPIENT.to_vec(),
             value: utils::u256_to_bytes(U256::from(900u64)).to_vec(),
@@ -283,12 +285,11 @@ async fn evaluate_rejects_volume_over_limit() {
         .await
         .unwrap();
 
-    use crate::db::{models::NewEvmTokenTransferLog, schema::evm_token_transfer_log};
-    insert_into(evm_token_transfer_log::table)
-        .values(NewEvmTokenTransferLog {
+    insert_into(db::schema::evm_token_transfer_log::table)
+        .values(db::models::NewEvmTokenTransferLog {
             grant_id,
             log_id: 0,
-            chain_id: CHAIN_ID as i32,
+            chain_id: CHAIN_ID.into(),
             token_contract: DAI.to_vec(),
             recipient_address: RECIPIENT.to_vec(),
             value: utils::u256_to_bytes(U256::from(1_000u64)).to_vec(),

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

@@ -1,4 +1,4 @@
-use std::sync::Mutex;
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 
 use alloy::{
     consensus::SignableTransaction,
@@ -6,9 +6,9 @@ use alloy::{
     primitives::{Address, B256, ChainId, Signature},
     signers::{Error, Result, Signer, SignerSync, utils::secret_key_to_address},
 };
-use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use async_trait::async_trait;
 use k256::ecdsa::{self, RecoveryId, SigningKey, signature::hazmat::PrehashSigner};
+use std::sync::Mutex;
 
 /// An Ethereum signer that stores its secp256k1 secret key inside a
 /// hardware-protected [`MemSafe`] cell.
@@ -82,8 +82,8 @@ impl SafeSigner {
         })
     }
 
+    #[expect(clippy::significant_drop_tightening, reason = "false positive")]
     fn sign_hash_inner(&self, hash: &B256) -> Result<Signature> {
-        #[allow(clippy::expect_used)]
         let mut cell = self.key.lock().expect("SafeSigner mutex poisoned");
         let reader = cell.read();
         let sig: (ecdsa::Signature, RecoveryId) = reader.sign_prehash(hash.as_ref())?;
@@ -96,7 +96,6 @@ impl SafeSigner {
         {
             return Err(Error::TransactionChainIdMismatch {
                 signer: chain_id,
-                #[allow(clippy::expect_used)]
                 tx: tx.chain_id().expect("Chain ID is guaranteed to be set"),
             });
         }

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

@@ -2,20 +2,20 @@ use alloy::primitives::U256;
 
 #[derive(thiserror::Error, Debug)]
 #[error("Expected {expected} bytes but got {actual} bytes")]
-pub struct LengthError {
-    pub expected: usize,
-    pub actual: usize,
+pub(super) struct LengthError {
+    pub(super) expected: usize,
+    pub(super) actual: usize,
 }
 
-pub fn u256_to_bytes(value: U256) -> [u8; 32] {
+pub const fn u256_to_bytes(value: U256) -> [u8; 32] {
     value.to_le_bytes()
 }
-pub fn bytes_to_u256(bytes: &[u8]) -> Option<U256> {
+pub(super) fn bytes_to_u256(bytes: &[u8]) -> Option<U256> {
     let bytes: [u8; 32] = bytes.try_into().ok()?;
     Some(U256::from_le_bytes(bytes))
 }
 
-pub fn try_bytes_to_u256(bytes: &[u8]) -> diesel::result::QueryResult<U256> {
+pub(super) fn try_bytes_to_u256(bytes: &[u8]) -> diesel::result::QueryResult<U256> {
     let bytes: [u8; 32] = bytes.try_into().map_err(|_| {
         diesel::result::Error::DeserializationError(Box::new(LengthError {
             expected: 32,

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

@@ -1,3 +1,7 @@
+use crate::{
+    grpc::request_tracker::RequestTracker,
+    peers::client::{ClientConnection, session::ClientSession},
+};
 use arbiter_proto::{
     proto::client::{
         ClientRequest, ClientResponse, client_request::Payload as ClientRequestPayload,
@@ -5,15 +9,11 @@ use arbiter_proto::{
     },
     transport::{Receiver, Sender, grpc::GrpcBi},
 };
+
 use kameo::actor::{ActorRef, Spawn as _};
 use tonic::Status;
 use tracing::{info, warn};
 
-use crate::{
-    actors::client::{ClientConnection, session::ClientSession},
-    grpc::request_tracker::RequestTracker,
-};
-
 mod auth;
 mod evm;
 mod inbound;
@@ -98,8 +98,7 @@ pub async fn start(mut conn: ClientConnection, mut bi: GrpcBi<ClientRequest, Cli
         Err(err) => {
             let _ = bi
                 .send(Err(Status::unauthenticated(format!(
-                    "Authentication failed: {}",
-                    err
+                    "Authentication failed: {err}",
                 ))))
                 .await;
             warn!(error = ?err, "Client authentication failed");

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

@@ -1,3 +1,7 @@
+use crate::{
+    grpc::{Convert, request_tracker::RequestTracker},
+    peers::client::{ClientConnection, auth},
+};
 use arbiter_crypto::authn;
 use arbiter_proto::{
     ClientMetadata,
@@ -17,22 +21,18 @@ use arbiter_proto::{
     },
     transport::{Bi, Error as TransportError, Receiver, Sender, grpc::GrpcBi},
 };
+
 use async_trait::async_trait;
 use tonic::Status;
 use tracing::warn;
 
-use crate::{
-    actors::client::{self, ClientConnection, auth},
-    grpc::request_tracker::RequestTracker,
-};
-
-pub struct AuthTransportAdapter<'a> {
+pub(super) struct AuthTransportAdapter<'a> {
     bi: &'a mut GrpcBi<ClientRequest, ClientResponse>,
     request_tracker: &'a mut RequestTracker,
 }
 
 impl<'a> AuthTransportAdapter<'a> {
-    pub fn new(
+    pub(super) const fn new(
         bi: &'a mut GrpcBi<ClientRequest, ClientResponse>,
         request_tracker: &'a mut RequestTracker,
     ) -> Self {
@@ -42,40 +42,6 @@ impl<'a> AuthTransportAdapter<'a> {
         }
     }
 
-    fn response_to_proto(response: auth::Outbound) -> AuthResponsePayload {
-        match response {
-            auth::Outbound::AuthChallenge { pubkey, nonce } => {
-                AuthResponsePayload::Challenge(ProtoAuthChallenge {
-                    pubkey: pubkey.to_bytes(),
-                    nonce,
-                })
-            }
-            auth::Outbound::AuthSuccess => {
-                AuthResponsePayload::Result(ProtoAuthResult::Success.into())
-            }
-        }
-    }
-
-    fn error_to_proto(error: auth::Error) -> AuthResponsePayload {
-        AuthResponsePayload::Result(
-            match error {
-                auth::Error::InvalidChallengeSolution => ProtoAuthResult::InvalidSignature,
-                auth::Error::ApproveError(auth::ApproveError::Denied) => {
-                    ProtoAuthResult::ApprovalDenied
-                }
-                auth::Error::ApproveError(auth::ApproveError::Upstream(
-                    crate::actors::flow_coordinator::ApprovalError::NoUserAgentsConnected,
-                )) => ProtoAuthResult::NoUserAgentsOnline,
-                auth::Error::ApproveError(auth::ApproveError::Internal)
-                | auth::Error::DatabasePoolUnavailable
-                | auth::Error::DatabaseOperationFailed
-                | auth::Error::IntegrityCheckFailed
-                | auth::Error::Transport => ProtoAuthResult::Internal,
-            }
-            .into(),
-        )
-    }
-
     async fn send_client_response(
         &mut self,
         payload: AuthResponsePayload,
@@ -103,8 +69,8 @@ impl Sender<Result<auth::Outbound, auth::Error>> for AuthTransportAdapter<'_> {
         item: Result<auth::Outbound, auth::Error>,
     ) -> Result<(), TransportError> {
         let payload = match item {
-            Ok(message) => AuthTransportAdapter::response_to_proto(message),
-            Err(err) => AuthTransportAdapter::error_to_proto(err),
+            Ok(message) => message.convert(),
+            Err(err) => err.convert(),
         };
 
         self.send_client_response(payload).await
@@ -167,7 +133,7 @@ impl Receiver<auth::Inbound> for AuthTransportAdapter<'_> {
                 };
                 Some(auth::Inbound::AuthChallengeRequest {
                     pubkey,
-                    metadata: client_metadata_from_proto(client_info),
+                    metadata: client_info.convert(),
                 })
             }
             AuthRequestPayload::ChallengeSolution(ProtoAuthChallengeSolution { signature }) => {
@@ -185,19 +151,69 @@ impl Receiver<auth::Inbound> for AuthTransportAdapter<'_> {
 
 impl Bi<auth::Inbound, Result<auth::Outbound, auth::Error>> for AuthTransportAdapter<'_> {}
 
-fn client_metadata_from_proto(metadata: ProtoClientInfo) -> ClientMetadata {
+impl Convert for ProtoClientInfo {
+    type Output = ClientMetadata;
+
+    fn convert(self) -> Self::Output {
         ClientMetadata {
-        name: metadata.name,
-        description: metadata.description,
-        version: metadata.version,
+            name: self.name,
+            description: self.description,
+            version: self.version,
+        }
     }
 }
 
-pub async fn start(
+impl Convert for auth::Error {
+    type Output = AuthResponsePayload;
+
+    fn convert(self) -> Self::Output {
+        use auth::Error::{
+            ApproveError, DatabaseOperationFailed, DatabasePoolUnavailable, IntegrityCheckFailed,
+            InvalidChallengeSolution, Transport,
+        };
+        AuthResponsePayload::Result(
+            match self {
+                InvalidChallengeSolution => ProtoAuthResult::InvalidSignature,
+                ApproveError(auth::ApproveError::Denied) => ProtoAuthResult::ApprovalDenied,
+                ApproveError(auth::ApproveError::Upstream(
+                    crate::actors::flow_coordinator::ApprovalError::NoUserAgentsConnected,
+                )) => ProtoAuthResult::NoUserAgentsOnline,
+                ApproveError(auth::ApproveError::Internal)
+                | DatabasePoolUnavailable
+                | DatabaseOperationFailed
+                | IntegrityCheckFailed
+                | Transport => ProtoAuthResult::Internal,
+            }
+            .into(),
+        )
+    }
+}
+
+impl Convert for auth::Outbound {
+    type Output = AuthResponsePayload;
+
+    fn convert(self) -> Self::Output {
+        match self {
+            Self::AuthChallenge { challenge } => {
+                AuthResponsePayload::Challenge(ProtoAuthChallenge {
+                    timestamp_nanos: challenge
+                        .timestamp
+                        .timestamp_nanos_opt()
+                        .expect("timestamp within range")
+                        as u64,
+                    random: challenge.nonce.to_vec(),
+                })
+            }
+            Self::AuthSuccess => AuthResponsePayload::Result(ProtoAuthResult::Success.into()),
+        }
+    }
+}
+
+pub(super) async fn start(
     conn: &mut ClientConnection,
     bi: &mut GrpcBi<ClientRequest, ClientResponse>,
     request_tracker: &mut RequestTracker,
 ) -> Result<i32, auth::Error> {
     let mut transport = AuthTransportAdapter::new(bi, request_tracker);
-    client::auth::authenticate(conn, &mut transport).await
+    auth::authenticate(conn, &mut transport).await
 }

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

@@ -1,3 +1,10 @@
+use crate::{
+    grpc::{
+        Convert, TryConvert,
+        common::inbound::{RawEvmAddress, RawEvmTransaction},
+    },
+    peers::client::session::{ClientSession, HandleSignTransaction, SignTransactionRpcError},
+};
 use arbiter_proto::proto::{
     client::{
         client_response::Payload as ClientResponsePayload,
@@ -11,19 +18,12 @@ use arbiter_proto::proto::{
         evm_sign_transaction_response::Result as EvmSignTransactionResult,
     },
 };
+
 use kameo::actor::ActorRef;
 use tonic::Status;
 use tracing::warn;
 
-use crate::{
-    actors::client::session::{ClientSession, HandleSignTransaction, SignTransactionRpcError},
-    grpc::{
-        Convert, TryConvert,
-        common::inbound::{RawEvmAddress, RawEvmTransaction},
-    },
-};
-
-fn wrap_response(payload: EvmResponsePayload) -> ClientResponsePayload {
+const fn wrap_response(payload: EvmResponsePayload) -> ClientResponsePayload {
     ClientResponsePayload::Evm(proto_evm::Response {
         payload: Some(payload),
     })

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

@@ -1,3 +1,7 @@
+use crate::{
+    actors::vault::VaultState,
+    peers::client::session::{ClientSession, Error, HandleQueryVaultState},
+};
 use arbiter_proto::proto::{
     client::{
         client_response::Payload as ClientResponsePayload,
@@ -8,15 +12,11 @@ use arbiter_proto::proto::{
     },
     shared::VaultState as ProtoVaultState,
 };
+
 use kameo::{actor::ActorRef, error::SendError};
 use tonic::Status;
 use tracing::warn;
 
-use crate::actors::{
-    client::session::{ClientSession, Error, HandleQueryVaultState},
-    keyholder::KeyHolderState,
-};
-
 pub(super) async fn dispatch(
     actor: &ActorRef<ClientSession>,
     req: proto_vault::Request,
@@ -28,11 +28,11 @@ pub(super) async fn dispatch(
     };
 
     match payload {
-        VaultRequestPayload::QueryState(_) => {
+        VaultRequestPayload::QueryState(()) => {
             let state = match actor.ask(HandleQueryVaultState {}).await {
-                Ok(KeyHolderState::Unbootstrapped) => ProtoVaultState::Unbootstrapped,
-                Ok(KeyHolderState::Sealed) => ProtoVaultState::Sealed,
-                Ok(KeyHolderState::Unsealed) => ProtoVaultState::Unsealed,
+                Ok(VaultState::Unbootstrapped) => ProtoVaultState::Unbootstrapped,
+                Ok(VaultState::Sealed) => ProtoVaultState::Sealed,
+                Ok(VaultState::Unsealed) => ProtoVaultState::Unsealed,
                 Err(SendError::HandlerError(Error::Internal)) => ProtoVaultState::Error,
                 Err(err) => {
                     warn!(error = ?err, "Failed to query vault state");

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

@@ -1,2 +1,2 @@
-pub mod inbound;
-pub mod outbound;
+pub(super) mod inbound;
+pub(super) mod outbound;

server/crates/arbiter-server/src/grpc/common/inbound.rs

@@ -1,8 +1,8 @@
-use alloy::{consensus::TxEip1559, primitives::Address, rlp::Decodable as _};
-
 use crate::grpc::TryConvert;
 
-pub struct RawEvmAddress(pub Vec<u8>);
+use alloy::{consensus::TxEip1559, primitives::Address, rlp::Decodable as _};
+
+pub(in crate::grpc) struct RawEvmAddress(pub(in crate::grpc) Vec<u8>);
 impl TryConvert for RawEvmAddress {
     type Output = Address;
 
@@ -21,7 +21,7 @@ impl TryConvert for RawEvmAddress {
     }
 }
 
-pub struct RawEvmTransaction(pub Vec<u8>);
+pub(in crate::grpc) struct RawEvmTransaction(pub(in crate::grpc) Vec<u8>);
 impl TryConvert for RawEvmTransaction {
     type Output = TxEip1559;
 

server/crates/arbiter-server/src/grpc/common/outbound.rs

@@ -1,4 +1,10 @@
-use alloy::primitives::U256;
+use crate::{
+    evm::{
+        PolicyError, VetError,
+        policies::{EvalViolation, SpecificMeaning},
+    },
+    grpc::Convert,
+};
 use arbiter_proto::proto::{
     evm::{
         EvmError as ProtoEvmError,
@@ -14,13 +20,7 @@ use arbiter_proto::proto::{
     },
 };
 
-use crate::{
-    evm::{
-        PolicyError, VetError,
-        policies::{EvalViolation, SpecificMeaning},
-    },
-    grpc::Convert,
-};
+use alloy::primitives::U256;
 
 fn u256_to_proto_bytes(value: U256) -> Vec<u8> {
     value.to_be_bytes::<32>().to_vec()
@@ -31,16 +31,16 @@ impl Convert for SpecificMeaning {
 
     fn convert(self) -> Self::Output {
         let kind = match self {
-            SpecificMeaning::EtherTransfer(meaning) => ProtoSpecificMeaningKind::EtherTransfer(
+            Self::EtherTransfer(meaning) => ProtoSpecificMeaningKind::EtherTransfer(
                 arbiter_proto::proto::shared::evm::EtherTransferMeaning {
                     to: meaning.to.to_vec(),
                     value: u256_to_proto_bytes(meaning.value),
                 },
             ),
-            SpecificMeaning::TokenTransfer(meaning) => ProtoSpecificMeaningKind::TokenTransfer(
+            Self::TokenTransfer(meaning) => ProtoSpecificMeaningKind::TokenTransfer(
                 arbiter_proto::proto::shared::evm::TokenTransferMeaning {
                     token: Some(ProtoTokenInfo {
-                        symbol: meaning.token.symbol.to_string(),
+                        symbol: meaning.token.symbol.to_owned(),
                         address: meaning.token.contract.to_vec(),
                         chain_id: meaning.token.chain,
                     }),
@@ -61,25 +61,21 @@ impl Convert for EvalViolation {
 
     fn convert(self) -> Self::Output {
         let kind = match self {
-            EvalViolation::InvalidTarget { target } => {
+            Self::InvalidTarget { target } => {
                 ProtoEvalViolationKind::InvalidTarget(target.to_vec())
             }
-            EvalViolation::GasLimitExceeded {
+            Self::GasLimitExceeded {
                 max_gas_fee_per_gas,
                 max_priority_fee_per_gas,
             } => ProtoEvalViolationKind::GasLimitExceeded(GasLimitExceededViolation {
                 max_gas_fee_per_gas: max_gas_fee_per_gas.map(u256_to_proto_bytes),
                 max_priority_fee_per_gas: max_priority_fee_per_gas.map(u256_to_proto_bytes),
             }),
-            EvalViolation::RateLimitExceeded => ProtoEvalViolationKind::RateLimitExceeded(()),
-            EvalViolation::VolumetricLimitExceeded => {
-                ProtoEvalViolationKind::VolumetricLimitExceeded(())
-            }
-            EvalViolation::InvalidTime => ProtoEvalViolationKind::InvalidTime(()),
-            EvalViolation::InvalidTransactionType => {
-                ProtoEvalViolationKind::InvalidTransactionType(())
-            }
-            EvalViolation::MismatchingChainId { expected, actual } => {
+            Self::RateLimitExceeded => ProtoEvalViolationKind::RateLimitExceeded(()),
+            Self::VolumetricLimitExceeded => ProtoEvalViolationKind::VolumetricLimitExceeded(()),
+            Self::InvalidTime => ProtoEvalViolationKind::InvalidTime(()),
+            Self::InvalidTransactionType => ProtoEvalViolationKind::InvalidTransactionType(()),
+            Self::MismatchingChainId { expected, actual } => {
                 ProtoEvalViolationKind::ChainIdMismatch(proto_eval_violation::ChainIdMismatch {
                     expected,
                     actual,
@@ -96,13 +92,13 @@ impl Convert for VetError {
 
     fn convert(self) -> Self::Output {
         let kind = match self {
-            VetError::ContractCreationNotSupported => {
+            Self::ContractCreationNotSupported => {
                 ProtoTransactionEvalErrorKind::ContractCreationNotSupported(())
             }
-            VetError::UnsupportedTransactionType => {
+            Self::UnsupportedTransactionType => {
                 ProtoTransactionEvalErrorKind::UnsupportedTransactionType(())
             }
-            VetError::Evaluated(meaning, policy_error) => match policy_error {
+            Self::Evaluated(meaning, policy_error) => match policy_error {
                 PolicyError::NoMatchingGrant => {
                     ProtoTransactionEvalErrorKind::NoMatchingGrant(NoMatchingGrantError {
                         meaning: Some(meaning.convert()),

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

@@ -1,3 +1,4 @@
+use crate::peers::{client::ClientConnection, user_agent::UserAgentConnection};
 use arbiter_proto::{
     proto::{
         client::{ClientRequest, ClientResponse},
@@ -5,15 +6,11 @@ use arbiter_proto::{
     },
     transport::grpc::GrpcBi,
 };
+
 use tokio_stream::wrappers::ReceiverStream;
 use tonic::{Request, Response, Status, async_trait};
 use tracing::info;
 
-use crate::{
-    actors::{client::ClientConnection, user_agent::UserAgentConnection},
-    grpc::user_agent::start,
-};
-
 mod request_tracker;
 
 pub mod client;
@@ -63,7 +60,7 @@ impl arbiter_proto::proto::arbiter_service_server::ArbiterService for super::Ser
 
         let (bi, rx) = GrpcBi::from_bi_stream(req_stream);
 
-        tokio::spawn(start(
+        tokio::spawn(user_agent::start(
             UserAgentConnection {
                 db: self.context.db.clone(),
                 actors: self.context.actors.clone(),

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

@@ -1,12 +1,12 @@
 use tonic::Status;
 
 #[derive(Default)]
-pub struct RequestTracker {
+pub(super) struct RequestTracker {
     next_request_id: i32,
 }
 
 impl RequestTracker {
-    pub fn request(&mut self, id: i32) -> Result<i32, Status> {
+    pub(super) fn request(&mut self, id: i32) -> Result<i32, Status> {
         if id < self.next_request_id {
             return Err(Status::invalid_argument("Duplicate request id"));
         }
@@ -20,7 +20,7 @@ impl RequestTracker {
 
     // This is used to set the response id for auth responses, which need to match the request id of the auth challenge request.
     // -1 offset is needed because request() increments the next_request_id after returning the current request id.
-    pub fn current_request_id(&self) -> i32 {
+    pub(super) const fn current_request_id(&self) -> i32 {
         self.next_request_id - 1
     }
 }

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

@@ -1,5 +1,7 @@
-use tokio::sync::mpsc;
-
+use crate::{
+    grpc::request_tracker::RequestTracker,
+    peers::user_agent::{OutOfBand, UserAgentConnection, UserAgentSession},
+};
 use arbiter_proto::{
     proto::user_agent::{
         UserAgentRequest, UserAgentResponse,
@@ -8,22 +10,20 @@ use arbiter_proto::{
     },
     transport::{Error as TransportError, Receiver, Sender, grpc::GrpcBi},
 };
+
 use async_trait::async_trait;
-use kameo::actor::{ActorRef, Spawn as _};
+use kameo::actor::ActorRef;
+use tokio::sync::mpsc;
 use tonic::Status;
 use tracing::{error, info, warn};
 
-use crate::{
-    actors::user_agent::{OutOfBand, UserAgentConnection, UserAgentSession},
-    grpc::request_tracker::RequestTracker,
-};
-
 mod auth;
 mod evm;
 mod inbound;
 mod outbound;
 mod sdk_client;
 mod vault;
+mod vault_gate;
 
 pub struct OutOfBandAdapter(mpsc::Sender<OutOfBand>);
 
@@ -124,21 +124,22 @@ pub async fn start(
 ) {
     let mut request_tracker = RequestTracker::default();
 
-    let pubkey = match auth::start(&mut conn, &mut bi, &mut request_tracker).await {
-        Ok(pubkey) => pubkey,
-        Err(e) => {
-            warn!(error = ?e, "Authentication failed");
-            return;
-        }
-    };
-
     let (oob_sender, oob_receiver) = mpsc::channel(16);
     let oob_adapter = OutOfBandAdapter(oob_sender);
 
-    let actor = UserAgentSession::spawn(UserAgentSession::new(conn, Box::new(oob_adapter)));
-    let actor_for_cleanup = actor.clone();
-
-    info!(?pubkey, "User authenticated successfully");
-    dispatch_loop(bi, actor, oob_receiver, request_tracker).await;
-    actor_for_cleanup.kill();
+    let actor = {
+        let transport = auth::AuthTransportAdapter::new(&mut bi, &mut request_tracker);
+        match crate::peers::user_agent::start(&mut conn, transport, Box::new(oob_adapter)).await {
+            Ok(actor) => actor,
+            Err(e) => {
+                warn!(error = ?e, "User agent connection failed");
+                return;
+            }
+        }
+    };
+
+    info!("User agent session established");
+
+    dispatch_loop(bi, actor.clone(), oob_receiver, request_tracker).await;
+    actor.kill();
 }

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

@@ -1,3 +1,4 @@
+use crate::{grpc::request_tracker::RequestTracker, peers::user_agent::auth};
 use arbiter_crypto::authn;
 use arbiter_proto::{
     proto::user_agent::{
@@ -13,22 +14,18 @@ use arbiter_proto::{
     },
     transport::{Bi, Error as TransportError, Receiver, Sender, grpc::GrpcBi},
 };
+
 use async_trait::async_trait;
 use tonic::Status;
 use tracing::warn;
 
-use crate::{
-    actors::user_agent::{UserAgentConnection, auth},
-    grpc::request_tracker::RequestTracker,
-};
-
-pub struct AuthTransportAdapter<'a> {
-    bi: &'a mut GrpcBi<UserAgentRequest, UserAgentResponse>,
-    request_tracker: &'a mut RequestTracker,
+pub(super) struct AuthTransportAdapter<'a> {
+    pub(super) bi: &'a mut GrpcBi<UserAgentRequest, UserAgentResponse>,
+    pub(super) request_tracker: &'a mut RequestTracker,
 }
 
 impl<'a> AuthTransportAdapter<'a> {
-    pub fn new(
+    pub(super) const fn new(
         bi: &'a mut GrpcBi<UserAgentRequest, UserAgentResponse>,
         request_tracker: &'a mut RequestTracker,
     ) -> Self {
@@ -38,16 +35,32 @@ impl<'a> AuthTransportAdapter<'a> {
         }
     }
 
-    async fn send_user_agent_response(
+    pub(super) const fn bi_mut(&mut self) -> &mut GrpcBi<UserAgentRequest, UserAgentResponse> {
+        self.bi
+    }
+
+    pub(super) const fn tracker_mut(&mut self) -> &mut RequestTracker {
+        self.request_tracker
+    }
+
+    pub(super) async fn send_response_payload(
         &mut self,
-        payload: AuthResponsePayload,
+        payload: UserAgentResponsePayload,
     ) -> Result<(), TransportError> {
         self.bi
             .send(Ok(UserAgentResponse {
                 id: Some(self.request_tracker.current_request_id()),
-                payload: Some(UserAgentResponsePayload::Auth(proto_auth::Response {
                 payload: Some(payload),
-                })),
+            }))
+            .await
+    }
+
+    async fn send_user_agent_response(
+        &mut self,
+        payload: AuthResponsePayload,
+    ) -> Result<(), TransportError> {
+        self.send_response_payload(UserAgentResponsePayload::Auth(proto_auth::Response {
+            payload: Some(payload),
         }))
         .await
     }
@@ -61,8 +74,15 @@ impl Sender<Result<auth::Outbound, auth::Error>> for AuthTransportAdapter<'_> {
     ) -> Result<(), TransportError> {
         use auth::{Error, Outbound};
         let payload = match item {
-            Ok(Outbound::AuthChallenge { nonce }) => {
-                AuthResponsePayload::Challenge(ProtoAuthChallenge { nonce })
+            Ok(Outbound::AuthChallenge { challenge }) => {
+                AuthResponsePayload::Challenge(ProtoAuthChallenge {
+                    timestamp_nanos: challenge
+                        .timestamp
+                        .timestamp_nanos_opt()
+                        .expect("timestamp within range")
+                        as u64,
+                    random: challenge.nonce.to_vec(),
+                })
             }
             Ok(Outbound::AuthSuccess) => {
                 AuthResponsePayload::Result(ProtoAuthResult::Success.into())
@@ -140,7 +160,6 @@ impl Receiver<auth::Inbound> for AuthTransportAdapter<'_> {
             AuthRequestPayload::ChallengeRequest(ProtoAuthChallengeRequest {
                 pubkey,
                 bootstrap_token,
-                key_type: _,
             }) => {
                 let Ok(pubkey) = authn::PublicKey::try_from(pubkey.as_slice()) else {
                     warn!(
@@ -163,12 +182,3 @@ impl Receiver<auth::Inbound> for AuthTransportAdapter<'_> {
 }
 
 impl Bi<auth::Inbound, Result<auth::Outbound, auth::Error>> for AuthTransportAdapter<'_> {}
-
-pub async fn start(
-    conn: &mut UserAgentConnection,
-    bi: &mut GrpcBi<UserAgentRequest, UserAgentResponse>,
-    request_tracker: &mut RequestTracker,
-) -> Result<authn::PublicKey, auth::Error> {
-    let transport = AuthTransportAdapter::new(bi, request_tracker);
-    auth::authenticate(conn, transport).await
-}

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

@@ -1,3 +1,17 @@
+use crate::{
+    grpc::{
+        Convert, TryConvert,
+        common::inbound::{RawEvmAddress, RawEvmTransaction},
+    },
+    peers::user_agent::{
+        UserAgentSession,
+        session::handlers::{
+            GrantMutationError, HandleEvmWalletCreate, HandleEvmWalletList, HandleGrantCreate,
+            HandleGrantDelete, HandleGrantList, HandleSignTransaction,
+            SignTransactionError as SessionSignTransactionError,
+        },
+    },
+};
 use arbiter_proto::proto::{
     evm::{
         EvmError as ProtoEvmError, EvmGrantCreateRequest, EvmGrantCreateResponse,
@@ -18,26 +32,12 @@ use arbiter_proto::proto::{
         user_agent_response::Payload as UserAgentResponsePayload,
     },
 };
+
 use kameo::actor::ActorRef;
 use tonic::Status;
 use tracing::warn;
 
-use crate::{
-    actors::user_agent::{
-        UserAgentSession,
-        session::connection::{
-            GrantMutationError, HandleEvmWalletCreate, HandleEvmWalletList, HandleGrantCreate,
-            HandleGrantDelete, HandleGrantList, HandleSignTransaction,
-            SignTransactionError as SessionSignTransactionError,
-        },
-    },
-    grpc::{
-        Convert, TryConvert,
-        common::inbound::{RawEvmAddress, RawEvmTransaction},
-    },
-};
-
-fn wrap_evm_response(payload: EvmResponsePayload) -> UserAgentResponsePayload {
+const fn wrap_evm_response(payload: EvmResponsePayload) -> UserAgentResponsePayload {
     UserAgentResponsePayload::Evm(proto_evm::Response {
         payload: Some(payload),
     })
@@ -52,8 +52,8 @@ pub(super) async fn dispatch(
     };
 
     match payload {
-        EvmRequestPayload::WalletCreate(_) => handle_wallet_create(actor).await,
-        EvmRequestPayload::WalletList(_) => handle_wallet_list(actor).await,
+        EvmRequestPayload::WalletCreate(()) => handle_wallet_create(actor).await,
+        EvmRequestPayload::WalletList(()) => handle_wallet_list(actor).await,
         EvmRequestPayload::GrantCreate(req) => handle_grant_create(actor, req).await,
         EvmRequestPayload::GrantDelete(req) => handle_grant_delete(actor, req).await,
         EvmRequestPayload::GrantList(_) => handle_grant_list(actor).await,

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

@@ -1,32 +1,32 @@
-use alloy::primitives::{Address, U256};
-use arbiter_proto::proto::evm::{
-    EtherTransferSettings as ProtoEtherTransferSettings, SharedSettings as ProtoSharedSettings,
-    SpecificGrant as ProtoSpecificGrant, TokenTransferSettings as ProtoTokenTransferSettings,
-    TransactionRateLimit as ProtoTransactionRateLimit, VolumeRateLimit as ProtoVolumeRateLimit,
-    specific_grant::Grant as ProtoSpecificGrantType,
-};
-use arbiter_proto::proto::user_agent::sdk_client::{
-    WalletAccess, WalletAccessEntry as SdkClientWalletAccess,
-};
-use chrono::{DateTime, TimeZone, Utc};
-use prost_types::Timestamp as ProtoTimestamp;
-use tonic::Status;
-
-use crate::db::models::{CoreEvmWalletAccess, NewEvmWalletAccess};
-use crate::grpc::Convert;
 use crate::{
+    db::models::{CoreEvmWalletAccess, NewEvmWalletAccess},
     evm::policies::{
         SharedGrantSettings, SpecificGrant, TransactionRateLimit, VolumeRateLimit, ether_transfer,
         token_transfers,
     },
+    grpc::Convert,
     grpc::TryConvert,
 };
+use arbiter_proto::{
+    proto::evm::{
+        EtherTransferSettings as ProtoEtherTransferSettings, SharedSettings as ProtoSharedSettings,
+        SpecificGrant as ProtoSpecificGrant, TokenTransferSettings as ProtoTokenTransferSettings,
+        TransactionRateLimit as ProtoTransactionRateLimit, VolumeRateLimit as ProtoVolumeRateLimit,
+        specific_grant::Grant as ProtoSpecificGrantType,
+    },
+    proto::user_agent::sdk_client::{WalletAccess, WalletAccessEntry as SdkClientWalletAccess},
+};
 
-fn address_from_bytes(bytes: Vec<u8>) -> Result<Address, Status> {
+use alloy::primitives::{Address, U256};
+use chrono::{DateTime, TimeZone, Utc};
+use prost_types::Timestamp as ProtoTimestamp;
+use tonic::Status;
+
+fn address_from_bytes(bytes: &[u8]) -> Result<Address, Status> {
     if bytes.len() != 20 {
         return Err(Status::invalid_argument("Invalid EVM address"));
     }
-    Ok(Address::from_slice(&bytes))
+    Ok(Address::from_slice(bytes))
 }
 
 fn u256_from_proto_bytes(bytes: &[u8]) -> Result<U256, Status> {
@@ -41,7 +41,7 @@ impl TryConvert for ProtoTimestamp {
     type Error = Status;
 
     fn try_convert(self) -> Result<DateTime<Utc>, Status> {
-        Utc.timestamp_opt(self.seconds, self.nanos as u32)
+        Utc.timestamp_opt(self.seconds, self.nanos.try_into().unwrap_or_default())
             .single()
             .ok_or_else(|| Status::invalid_argument("Invalid timestamp"))
     }
@@ -116,7 +116,8 @@ impl TryConvert for ProtoSpecificGrant {
                 limit,
             })) => Ok(SpecificGrant::EtherTransfer(ether_transfer::Settings {
                 target: targets
-                    .into_iter()
+                    .iter()
+                    .map(Vec::as_slice)
                     .map(address_from_bytes)
                     .collect::<Result<_, _>>()?,
                 limit: limit
@@ -130,8 +131,10 @@ impl TryConvert for ProtoSpecificGrant {
                 target,
                 volume_limits,
             })) => Ok(SpecificGrant::TokenTransfer(token_transfers::Settings {
-                token_contract: address_from_bytes(token_contract)?,
-                target: target.map(address_from_bytes).transpose()?,
+                token_contract: address_from_bytes(&token_contract)?,
+                target: target
+                    .map(|target| address_from_bytes(&target))
+                    .transpose()?,
                 volume_limits: volume_limits
                     .into_iter()
                     .map(ProtoVolumeRateLimit::try_convert)

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

@@ -1,3 +1,8 @@
+use crate::{
+    db::models::EvmWalletAccess,
+    evm::policies::{SharedGrantSettings, SpecificGrant, TransactionRateLimit, VolumeRateLimit},
+    grpc::Convert,
+};
 use arbiter_proto::proto::{
     evm::{
         EtherTransferSettings as ProtoEtherTransferSettings, SharedSettings as ProtoSharedSettings,
@@ -7,22 +12,17 @@ use arbiter_proto::proto::{
     },
     user_agent::sdk_client::{WalletAccess, WalletAccessEntry as ProtoSdkClientWalletAccess},
 };
+
 use chrono::{DateTime, Utc};
 use prost_types::Timestamp as ProtoTimestamp;
 
-use crate::{
-    db::models::EvmWalletAccess,
-    evm::policies::{SharedGrantSettings, SpecificGrant, TransactionRateLimit, VolumeRateLimit},
-    grpc::Convert,
-};
-
 impl Convert for DateTime<Utc> {
     type Output = ProtoTimestamp;
 
     fn convert(self) -> ProtoTimestamp {
         ProtoTimestamp {
             seconds: self.timestamp(),
-            nanos: self.timestamp_subsec_nanos() as i32,
+            nanos: self.timestamp_subsec_nanos().try_into().unwrap_or(i32::MAX),
         }
     }
 }
@@ -74,13 +74,13 @@ impl Convert for SpecificGrant {
 
     fn convert(self) -> ProtoSpecificGrant {
         let grant = match self {
-            SpecificGrant::EtherTransfer(s) => {
+            Self::EtherTransfer(s) => {
                 ProtoSpecificGrantType::EtherTransfer(ProtoEtherTransferSettings {
                     targets: s.target.into_iter().map(|a| a.to_vec()).collect(),
                     limit: Some(s.limit.convert()),
                 })
             }
-            SpecificGrant::TokenTransfer(s) => {
+            Self::TokenTransfer(s) => {
                 ProtoSpecificGrantType::TokenTransfer(ProtoTokenTransferSettings {
                     token_contract: s.token_contract.to_vec(),
                     target: s.target.map(|a| a.to_vec()),

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

@@ -1,3 +1,14 @@
+use crate::{
+    db::models::NewEvmWalletAccess,
+    grpc::Convert,
+    peers::user_agent::{
+        OutOfBand, UserAgentSession,
+        session::handlers::{
+            HandleGrantEvmWalletAccess, HandleListWalletAccess, HandleNewClientApprove,
+            HandleRevokeEvmWalletAccess, HandleSdkClientList,
+        },
+    },
+};
 use arbiter_crypto::authn;
 use arbiter_proto::proto::{
     shared::ClientInfo as ProtoClientMetadata,
@@ -16,23 +27,12 @@ use arbiter_proto::proto::{
         user_agent_response::Payload as UserAgentResponsePayload,
     },
 };
+
 use kameo::actor::ActorRef;
 use tonic::Status;
 use tracing::{info, warn};
 
-use crate::{
-    actors::user_agent::{
-        OutOfBand, UserAgentSession,
-        session::connection::{
-            HandleGrantEvmWalletAccess, HandleListWalletAccess, HandleNewClientApprove,
-            HandleRevokeEvmWalletAccess, HandleSdkClientList,
-        },
-    },
-    db::models::NewEvmWalletAccess,
-    grpc::Convert,
-};
-
-fn wrap_sdk_client_response(payload: SdkClientResponsePayload) -> UserAgentResponsePayload {
+const fn wrap_sdk_client_response(payload: SdkClientResponsePayload) -> UserAgentResponsePayload {
     UserAgentResponsePayload::SdkClient(proto_sdk_client::Response {
         payload: Some(payload),
     })
@@ -75,14 +75,14 @@ pub(super) async fn dispatch(
         SdkClientRequestPayload::Revoke(_) => Err(Status::unimplemented(
             "SdkClientRevoke is not yet implemented",
         )),
-        SdkClientRequestPayload::List(_) => handle_list(actor).await,
+        SdkClientRequestPayload::List(()) => handle_list(actor).await,
         SdkClientRequestPayload::GrantWalletAccess(req) => {
             handle_grant_wallet_access(actor, req).await
         }
         SdkClientRequestPayload::RevokeWalletAccess(req) => {
             handle_revoke_wallet_access(actor, req).await
         }
-        SdkClientRequestPayload::ListWalletAccess(_) => handle_list_wallet_access(actor).await,
+        SdkClientRequestPayload::ListWalletAccess(()) => handle_list_wallet_access(actor).await,
     }
 }
 
@@ -91,7 +91,7 @@ async fn handle_connection_response(
     resp: ProtoSdkClientConnectionResponse,
 ) -> Result<Option<UserAgentResponsePayload>, Status> {
     let pubkey = authn::PublicKey::try_from(resp.pubkey.as_slice())
-        .map_err(|_| Status::invalid_argument("Invalid ML-DSA public key"))?;
+        .map_err(|()| Status::invalid_argument("Invalid ML-DSA public key"))?;
 
     actor
         .ask(HandleNewClientApprove {
@@ -116,12 +116,17 @@ async fn handle_list(
                 .into_iter()
                 .map(|(client, metadata)| ProtoSdkClientEntry {
                     id: client.id,
-                    pubkey: client.public_key.to_vec(),
+                    pubkey: client.public_key.clone(),
                     info: Some(ProtoClientMetadata {
                         name: metadata.name,
                         description: metadata.description,
                         version: metadata.version,
                     }),
+                    #[expect(
+                        clippy::cast_possible_truncation,
+                        clippy::as_conversions,
+                        reason = "fixme! #84"
+                    )]
                     created_at: client.created_at.0.timestamp() as i32,
                 })
                 .collect(),
@@ -142,7 +147,7 @@ async fn handle_grant_wallet_access(
     actor: &ActorRef<UserAgentSession>,
     req: ProtoSdkClientGrantWalletAccess,
 ) -> Result<Option<UserAgentResponsePayload>, Status> {
-    let entries: Vec<NewEvmWalletAccess> = req.accesses.into_iter().map(|a| a.convert()).collect();
+    let entries: Vec<NewEvmWalletAccess> = req.accesses.into_iter().map(Convert::convert).collect();
     match actor.ask(HandleGrantEvmWalletAccess { entries }).await {
         Ok(()) => {
             info!("Successfully granted wallet access");
@@ -182,7 +187,7 @@ async fn handle_list_wallet_access(
     match actor.ask(HandleListWalletAccess {}).await {
         Ok(accesses) => Ok(Some(wrap_sdk_client_response(
             SdkClientResponsePayload::ListWalletAccess(ListWalletAccessResponse {
-                accesses: accesses.into_iter().map(|a| a.convert()).collect(),
+                accesses: accesses.into_iter().map(Convert::convert).collect(),
             }),
         ))),
         Err(err) => {

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

@@ -1,54 +1,28 @@
-use arbiter_proto::proto::shared::VaultState as ProtoVaultState;
-use arbiter_proto::proto::user_agent::{
+use crate::{
+    actors::vault::VaultState,
+    peers::user_agent::{UserAgentSession, session::handlers::HandleQueryVaultState},
+};
+use arbiter_proto::{
+    proto::shared::VaultState as ProtoVaultState,
+    proto::user_agent::{
         user_agent_response::Payload as UserAgentResponsePayload,
         vault::{
-        self as proto_vault,
-        bootstrap::{
-            self as proto_bootstrap, BootstrapEncryptedKey as ProtoBootstrapEncryptedKey,
-            BootstrapResult as ProtoBootstrapResult,
-        },
-        request::Payload as VaultRequestPayload,
+            self as proto_vault, request::Payload as VaultRequestPayload,
             response::Payload as VaultResponsePayload,
-        unseal::{
-            self as proto_unseal, UnsealEncryptedKey as ProtoUnsealEncryptedKey,
-            UnsealResult as ProtoUnsealResult, UnsealStart,
-            request::Payload as UnsealRequestPayload, response::Payload as UnsealResponsePayload,
         },
     },
 };
-use kameo::{actor::ActorRef, error::SendError};
+
+use kameo::actor::ActorRef;
 use tonic::Status;
 use tracing::warn;
 
-use crate::actors::{
-    keyholder::KeyHolderState,
-    user_agent::{
-        UserAgentSession,
-        session::connection::{
-            BootstrapError, HandleBootstrapEncryptedKey, HandleQueryVaultState,
-            HandleUnsealEncryptedKey, HandleUnsealRequest, UnsealError,
-        },
-    },
-};
-
-fn wrap_vault_response(payload: VaultResponsePayload) -> UserAgentResponsePayload {
+const fn wrap_vault_response(payload: VaultResponsePayload) -> UserAgentResponsePayload {
     UserAgentResponsePayload::Vault(proto_vault::Response {
         payload: Some(payload),
     })
 }
 
-fn wrap_unseal_response(payload: UnsealResponsePayload) -> UserAgentResponsePayload {
-    wrap_vault_response(VaultResponsePayload::Unseal(proto_unseal::Response {
-        payload: Some(payload),
-    }))
-}
-
-fn wrap_bootstrap_response(result: ProtoBootstrapResult) -> UserAgentResponsePayload {
-    wrap_vault_response(VaultResponsePayload::Bootstrap(proto_bootstrap::Response {
-        result: result.into(),
-    }))
-}
-
 pub(super) async fn dispatch(
     actor: &ActorRef<UserAgentSession>,
     req: proto_vault::Request,
@@ -58,117 +32,22 @@ pub(super) async fn dispatch(
     };
 
     match payload {
-        VaultRequestPayload::QueryState(_) => handle_query_vault_state(actor).await,
-        VaultRequestPayload::Unseal(req) => dispatch_unseal_request(actor, req).await,
-        VaultRequestPayload::Bootstrap(req) => handle_bootstrap_request(actor, req).await,
+        VaultRequestPayload::QueryState(()) => handle_query_vault_state(actor).await,
+        VaultRequestPayload::Unseal(_) | VaultRequestPayload::Bootstrap(_) => {
+            Err(Status::permission_denied(
+                "Vault is already unsealed; unseal/bootstrap not permitted in session",
+            ))
         }
     }
-
-async fn dispatch_unseal_request(
-    actor: &ActorRef<UserAgentSession>,
-    req: proto_unseal::Request,
-) -> Result<Option<UserAgentResponsePayload>, Status> {
-    let Some(payload) = req.payload else {
-        return Err(Status::invalid_argument("Missing unseal request payload"));
-    };
-
-    match payload {
-        UnsealRequestPayload::Start(req) => handle_unseal_start(actor, req).await,
-        UnsealRequestPayload::EncryptedKey(req) => handle_unseal_encrypted_key(actor, req).await,
-    }
-}
-
-async fn handle_unseal_start(
-    actor: &ActorRef<UserAgentSession>,
-    req: UnsealStart,
-) -> Result<Option<UserAgentResponsePayload>, Status> {
-    let client_pubkey = <[u8; 32]>::try_from(req.client_pubkey)
-        .map(x25519_dalek::PublicKey::from)
-        .map_err(|_| Status::invalid_argument("Invalid X25519 public key"))?;
-
-    let response = actor
-        .ask(HandleUnsealRequest { client_pubkey })
-        .await
-        .map_err(|err| {
-            warn!(error = ?err, "Failed to handle unseal start request");
-            Status::internal("Failed to start unseal flow")
-        })?;
-
-    Ok(Some(wrap_unseal_response(UnsealResponsePayload::Start(
-        proto_unseal::UnsealStartResponse {
-            server_pubkey: response.server_pubkey.as_bytes().to_vec(),
-        },
-    ))))
-}
-
-async fn handle_unseal_encrypted_key(
-    actor: &ActorRef<UserAgentSession>,
-    req: ProtoUnsealEncryptedKey,
-) -> Result<Option<UserAgentResponsePayload>, Status> {
-    let result = match actor
-        .ask(HandleUnsealEncryptedKey {
-            nonce: req.nonce,
-            ciphertext: req.ciphertext,
-            associated_data: req.associated_data,
-        })
-        .await
-    {
-        Ok(()) => ProtoUnsealResult::Success,
-        Err(SendError::HandlerError(UnsealError::InvalidKey)) => ProtoUnsealResult::InvalidKey,
-        Err(err) => {
-            warn!(error = ?err, "Failed to handle unseal request");
-            return Err(Status::internal("Failed to unseal vault"));
-        }
-    };
-    Ok(Some(wrap_unseal_response(UnsealResponsePayload::Result(
-        result.into(),
-    ))))
-}
-
-async fn handle_bootstrap_request(
-    actor: &ActorRef<UserAgentSession>,
-    req: proto_bootstrap::Request,
-) -> Result<Option<UserAgentResponsePayload>, Status> {
-    let encrypted_key = req
-        .encrypted_key
-        .ok_or_else(|| Status::invalid_argument("Missing bootstrap encrypted key"))?;
-    handle_bootstrap_encrypted_key(actor, encrypted_key).await
-}
-
-async fn handle_bootstrap_encrypted_key(
-    actor: &ActorRef<UserAgentSession>,
-    req: ProtoBootstrapEncryptedKey,
-) -> Result<Option<UserAgentResponsePayload>, Status> {
-    let result = match actor
-        .ask(HandleBootstrapEncryptedKey {
-            nonce: req.nonce,
-            ciphertext: req.ciphertext,
-            associated_data: req.associated_data,
-        })
-        .await
-    {
-        Ok(()) => ProtoBootstrapResult::Success,
-        Err(SendError::HandlerError(BootstrapError::InvalidKey)) => {
-            ProtoBootstrapResult::InvalidKey
-        }
-        Err(SendError::HandlerError(BootstrapError::AlreadyBootstrapped)) => {
-            ProtoBootstrapResult::AlreadyBootstrapped
-        }
-        Err(err) => {
-            warn!(error = ?err, "Failed to handle bootstrap request");
-            return Err(Status::internal("Failed to bootstrap vault"));
-        }
-    };
-    Ok(Some(wrap_bootstrap_response(result)))
 }
 
 async fn handle_query_vault_state(
     actor: &ActorRef<UserAgentSession>,
 ) -> Result<Option<UserAgentResponsePayload>, Status> {
     let state = match actor.ask(HandleQueryVaultState {}).await {
-        Ok(KeyHolderState::Unbootstrapped) => ProtoVaultState::Unbootstrapped,
-        Ok(KeyHolderState::Sealed) => ProtoVaultState::Sealed,
-        Ok(KeyHolderState::Unsealed) => ProtoVaultState::Unsealed,
+        Ok(VaultState::Unbootstrapped) => ProtoVaultState::Unbootstrapped,
+        Ok(VaultState::Sealed) => ProtoVaultState::Sealed,
+        Ok(VaultState::Unsealed) => ProtoVaultState::Unsealed,
         Err(err) => {
             warn!(error = ?err, "Failed to query vault state");
             ProtoVaultState::Error

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

@@ -0,0 +1,79 @@
+use super::auth::AuthTransportAdapter;
+use crate::{
+    grpc::TryConvert,
+    peers::user_agent::vault_gate::{self as vault_gate},
+};
+use arbiter_proto::transport::{Bi, Error as TransportError, Receiver, Sender};
+
+use async_trait::async_trait;
+use tonic::Status;
+use tracing::warn;
+
+mod inbound;
+mod outbound;
+
+#[async_trait]
+impl Receiver<vault_gate::Inbound> for AuthTransportAdapter<'_> {
+    async fn recv(&mut self) -> Option<vault_gate::Inbound> {
+        let request = match self.bi_mut().recv().await? {
+            Ok(request) => request,
+            Err(error) => {
+                warn!(
+                    ?error,
+                    "Failed to receive user agent request during vault gate"
+                );
+                return None;
+            }
+        };
+
+        if let Err(err) = self.tracker_mut().request(request.id) {
+            let _ = self.bi_mut().send(Err(err)).await;
+            return None;
+        }
+
+        let Some(payload) = request.payload else {
+            let _ = self
+                .bi_mut()
+                .send(Err(Status::invalid_argument("Missing request payload")))
+                .await;
+            return None;
+        };
+
+        match payload.try_convert() {
+            Ok(inbound) => Some(inbound),
+            Err(status) => {
+                let _ = self.bi_mut().send(Err(status)).await;
+                None
+            }
+        }
+    }
+}
+
+#[async_trait]
+impl Sender<Result<vault_gate::Outbound, vault_gate::Error>> for AuthTransportAdapter<'_> {
+    async fn send(
+        &mut self,
+        item: Result<vault_gate::Outbound, vault_gate::Error>,
+    ) -> Result<(), TransportError> {
+        let outbound = match item {
+            Ok(outbound) => outbound,
+            Err(err) => {
+                warn!(?err, "vault gate produced transport-level error");
+                return self
+                    .bi_mut()
+                    .send(Err(Status::internal(err.to_string())))
+                    .await;
+            }
+        };
+
+        match outbound.try_convert() {
+            Ok(payload) => self.send_response_payload(payload).await,
+            Err(status) => self.bi_mut().send(Err(status)).await,
+        }
+    }
+}
+
+impl Bi<vault_gate::Inbound, Result<vault_gate::Outbound, vault_gate::Error>>
+    for AuthTransportAdapter<'_>
+{
+}

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

@@ -0,0 +1,129 @@
+use crate::{
+    grpc::{Convert, TryConvert},
+    peers::user_agent::vault_gate::{
+        self as vault_gate, HandleBootstrapEncryptedKey, HandleHandshake, HandleUnsealEncryptedKey,
+    },
+};
+use arbiter_proto::proto::user_agent::{
+    user_agent_request::Payload as UserAgentRequestPayload,
+    vault::{
+        self as proto_vault,
+        bootstrap::{self as proto_bootstrap},
+        request::Payload as VaultRequestPayload,
+        unseal::{self as proto_unseal, request::Payload as UnsealRequestPayload},
+    },
+};
+
+use tonic::Status;
+
+impl TryConvert for UserAgentRequestPayload {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        match self {
+            Self::Vault(req) => req.try_convert(),
+            _ => Err(Status::permission_denied(
+                "Only vault operations are permitted before unsealing",
+            )),
+        }
+    }
+}
+
+impl TryConvert for proto_vault::Request {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        self.payload
+            .ok_or_else(|| Status::invalid_argument("Missing vault request payload"))?
+            .try_convert()
+    }
+}
+
+impl TryConvert for VaultRequestPayload {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        match self {
+            Self::QueryState(()) => Ok(vault_gate::Inbound::HandleVaultState),
+            Self::Unseal(req) => req.try_convert(),
+            Self::Bootstrap(req) => req.try_convert(),
+        }
+    }
+}
+
+impl TryConvert for proto_unseal::Request {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        self.payload
+            .ok_or_else(|| Status::invalid_argument("Missing unseal request payload"))?
+            .try_convert()
+    }
+}
+
+impl TryConvert for UnsealRequestPayload {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        match self {
+            Self::Start(start) => start.try_convert(),
+            Self::EncryptedKey(key) => Ok(key.convert()),
+        }
+    }
+}
+
+impl TryConvert for proto_unseal::UnsealStart {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        let bytes = <[u8; 32]>::try_from(self.client_pubkey)
+            .map_err(|_| Status::invalid_argument("Invalid X25519 public key"))?;
+        Ok(vault_gate::Inbound::HandleHandshake(HandleHandshake {
+            client_pubkey: x25519_dalek::PublicKey::from(bytes),
+        }))
+    }
+}
+
+impl Convert for proto_unseal::UnsealEncryptedKey {
+    type Output = vault_gate::Inbound;
+
+    fn convert(self) -> vault_gate::Inbound {
+        vault_gate::Inbound::HandleUnsealEncryptedKey(HandleUnsealEncryptedKey {
+            nonce: self.nonce,
+            ciphertext: self.ciphertext,
+            associated_data: self.associated_data,
+        })
+    }
+}
+
+impl TryConvert for proto_bootstrap::Request {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        self.encrypted_key
+            .ok_or_else(|| Status::invalid_argument("Missing bootstrap encrypted key"))?
+            .try_convert()
+    }
+}
+
+impl TryConvert for proto_bootstrap::BootstrapEncryptedKey {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        Ok(vault_gate::Inbound::HandleBootstrapEncryptedKey(
+            HandleBootstrapEncryptedKey {
+                nonce: self.nonce,
+                ciphertext: self.ciphertext,
+                associated_data: self.associated_data,
+            },
+        ))
+    }
+}

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

@@ -0,0 +1,115 @@
+use crate::{
+    actors::vault::VaultState,
+    grpc::{Convert, TryConvert},
+    peers::user_agent::vault_gate::{self as vault_gate},
+};
+use arbiter_proto::proto::{
+    shared::VaultState as ProtoVaultState,
+    user_agent::{
+        user_agent_response::Payload as UserAgentResponsePayload,
+        vault::{
+            self as proto_vault,
+            bootstrap::{self as proto_bootstrap, BootstrapResult as ProtoBootstrapResult},
+            response::Payload as VaultResponsePayload,
+            unseal::{
+                self as proto_unseal, UnsealResult as ProtoUnsealResult,
+                response::Payload as UnsealResponsePayload,
+            },
+        },
+    },
+};
+
+use tonic::Status;
+use tracing::warn;
+
+const fn wrap_vault_response(payload: VaultResponsePayload) -> UserAgentResponsePayload {
+    UserAgentResponsePayload::Vault(proto_vault::Response {
+        payload: Some(payload),
+    })
+}
+
+const fn wrap_unseal_response(payload: UnsealResponsePayload) -> UserAgentResponsePayload {
+    wrap_vault_response(VaultResponsePayload::Unseal(proto_unseal::Response {
+        payload: Some(payload),
+    }))
+}
+
+fn wrap_bootstrap_response(result: ProtoBootstrapResult) -> UserAgentResponsePayload {
+    wrap_vault_response(VaultResponsePayload::Bootstrap(proto_bootstrap::Response {
+        result: result.into(),
+    }))
+}
+
+impl Convert for VaultState {
+    type Output = UserAgentResponsePayload;
+
+    fn convert(self) -> UserAgentResponsePayload {
+        let proto_state = match self {
+            Self::Unbootstrapped => ProtoVaultState::Unbootstrapped,
+            Self::Sealed => ProtoVaultState::Sealed,
+            Self::Unsealed => ProtoVaultState::Unsealed,
+        };
+        wrap_vault_response(VaultResponsePayload::State(proto_state.into()))
+    }
+}
+
+impl Convert for vault_gate::HandshakeResponse {
+    type Output = UserAgentResponsePayload;
+
+    fn convert(self) -> UserAgentResponsePayload {
+        wrap_unseal_response(UnsealResponsePayload::Start(
+            proto_unseal::UnsealStartResponse {
+                server_pubkey: self.server_pubkey.as_bytes().to_vec(),
+            },
+        ))
+    }
+}
+
+impl TryConvert for vault_gate::Outbound {
+    type Output = UserAgentResponsePayload;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<UserAgentResponsePayload, Status> {
+        match self {
+            Self::HandleVaultState(result) => result
+                .map_err(|err| {
+                    warn!(?err, "vault state query failed");
+                    Status::internal("Failed to query vault state")
+                })
+                .map(VaultState::convert),
+            Self::HandleHandshake(result) => result
+                .map_err(|err| {
+                    warn!(?err, "handshake failed");
+                    Status::internal("Failed to start unseal flow")
+                })
+                .map(vault_gate::HandshakeResponse::convert),
+            Self::HandleUnsealEncryptedKey(result) => {
+                let proto_result = match result {
+                    Ok(()) => ProtoUnsealResult::Success,
+                    Err(vault_gate::Error::InvalidKey) => ProtoUnsealResult::InvalidKey,
+                    Err(err) => {
+                        warn!(?err, "unseal failed");
+                        return Err(Status::internal("Failed to unseal vault"));
+                    }
+                };
+                Ok(wrap_unseal_response(UnsealResponsePayload::Result(
+                    proto_result.into(),
+                )))
+            }
+            Self::HandleBootstrapEncryptedKey(result) => {
+                let proto_result = match result {
+                    Ok(()) => ProtoBootstrapResult::Success,
+                    Err(vault_gate::Error::InvalidKey) => ProtoBootstrapResult::InvalidKey,
+                    Err(vault_gate::Error::AlreadyBootstrapped) => {
+                        ProtoBootstrapResult::AlreadyBootstrapped
+                    }
+                    Err(err) => {
+                        warn!(?err, "bootstrap failed");
+                        return Err(Status::internal("Failed to bootstrap vault"));
+                    }
+                };
+                Ok(wrap_bootstrap_response(proto_result))
+            }
+        }
+    }
+}

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

@@ -1,4 +1,3 @@
-#![forbid(unsafe_code)]
 use crate::context::ServerContext;
 
 pub mod actors;
@@ -7,6 +6,7 @@ pub mod crypto;
 pub mod db;
 pub mod evm;
 pub mod grpc;
+pub mod peers;
 pub mod utils;
 
 pub struct Server {
@@ -14,7 +14,7 @@ pub struct Server {
 }
 
 impl Server {
-    pub fn new(context: ServerContext) -> Self {
+    pub const fn new(context: ServerContext) -> Self {
         Self { context }
     }
 }

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

@@ -1,9 +1,9 @@
-use std::net::SocketAddr;
-
-use anyhow::anyhow;
 use arbiter_proto::{proto::arbiter_service_server::ArbiterServiceServer, url::ArbiterUrl};
 use arbiter_server::{Server, actors::bootstrap::GetToken, context::ServerContext, db};
+
+use anyhow::anyhow;
 use rustls::crypto::aws_lc_rs;
+use std::net::SocketAddr;
 use tonic::transport::{Identity, ServerTlsConfig};
 use tracing::info;
 

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

@@ -1,22 +1,9 @@
-use arbiter_crypto::authn::{self, CLIENT_CONTEXT};
-use arbiter_proto::{
-    ClientMetadata,
-    transport::{Bi, expect_message},
-};
-use chrono::Utc;
-use diesel::{
-    ExpressionMethods as _, OptionalExtension as _, QueryDsl as _, SelectableHelper as _,
-    dsl::insert_into, update,
-};
-use diesel_async::RunQueryDsl as _;
-use kameo::{actor::ActorRef, error::SendError};
-use tracing::error;
-
+use super::{ClientConnection, ClientCredentials, ClientProfile};
 use crate::{
     actors::{
-        client::{ClientConnection, ClientCredentials, ClientProfile},
+        GlobalActors,
         flow_coordinator::{self, RequestClientApproval},
-        keyholder::KeyHolder,
+        vault::Vault,
     },
     crypto::integrity::{self, AttestationStatus},
     db::{
@@ -25,6 +12,20 @@ use crate::{
         schema::program_client,
     },
 };
+use arbiter_crypto::authn::{self, AuthChallenge, CLIENT_CONTEXT};
+use arbiter_proto::{
+    ClientMetadata,
+    transport::{Bi, expect_message},
+};
+
+use chrono::Utc;
+use diesel::{
+    ExpressionMethods as _, OptionalExtension as _, QueryDsl as _, SelectableHelper as _,
+    dsl::insert_into, update,
+};
+use diesel_async::RunQueryDsl as _;
+use kameo::{actor::ActorRef, error::SendError};
+use tracing::error;
 
 #[derive(thiserror::Error, Debug, Clone, PartialEq, Eq)]
 pub enum Error {
@@ -72,19 +73,14 @@ pub enum Inbound {
 
 #[derive(Debug, Clone)]
 pub enum Outbound {
-    AuthChallenge {
-        pubkey: authn::PublicKey,
-        nonce: i32,
-    },
+    AuthChallenge { challenge: AuthChallenge },
     AuthSuccess,
 }
 
-/// Returns the current nonce and client ID for a registered client.
-/// Returns `None` if the pubkey is not registered.
-async fn get_current_nonce_and_id(
+async fn get_client_id(
     db: &db::DatabasePool,
     pubkey: &authn::PublicKey,
-) -> Result<Option<(i32, i32)>, Error> {
+) -> Result<Option<i32>, Error> {
     let pubkey_bytes = pubkey.to_bytes();
     let mut conn = db.get().await.map_err(|e| {
         error!(error = ?e, "Database pool error");
@@ -92,8 +88,8 @@ async fn get_current_nonce_and_id(
     })?;
     program_client::table
         .filter(program_client::public_key.eq(&pubkey_bytes))
-        .select((program_client::id, program_client::nonce))
-        .first::<(i32, i32)>(&mut conn)
+        .select(program_client::id)
+        .first::<i32>(&mut conn)
         .await
         .optional()
         .map_err(|e| {
@@ -104,7 +100,7 @@ async fn get_current_nonce_and_id(
 
 async fn verify_integrity(
     db: &db::DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
     pubkey: &authn::PublicKey,
 ) -> Result<(), Error> {
     let mut db_conn = db.get().await.map_err(|e| {
@@ -112,17 +108,16 @@ async fn verify_integrity(
         Error::DatabasePoolUnavailable
     })?;
 
-    let (id, nonce) = get_current_nonce_and_id(db, pubkey).await?.ok_or_else(|| {
+    let id = get_client_id(db, pubkey).await?.ok_or_else(|| {
         error!("Client not found during integrity verification");
         Error::DatabaseOperationFailed
     })?;
 
     let attestation = integrity::verify_entity(
         &mut db_conn,
-        keyholder,
+        vault,
         &ClientCredentials {
             pubkey: pubkey.clone(),
-            nonce,
         },
         id,
     )
@@ -140,57 +135,7 @@ async fn verify_integrity(
     Ok(())
 }
 
-/// Atomically increments the nonce and re-signs the integrity envelope.
-/// Returns the new nonce, which is used as the challenge nonce.
-async fn create_nonce(
-    db: &db::DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
-    pubkey: &authn::PublicKey,
-) -> Result<i32, Error> {
-    let pubkey_bytes = pubkey.to_bytes();
-    let pubkey = pubkey.clone();
-
-    let mut conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::DatabasePoolUnavailable
-    })?;
-
-    conn.exclusive_transaction(|conn| {
-        let keyholder = keyholder.clone();
-        let pubkey = pubkey.clone();
-        Box::pin(async move {
-            let (id, new_nonce): (i32, i32) = update(program_client::table)
-                .filter(program_client::public_key.eq(&pubkey_bytes))
-                .set(program_client::nonce.eq(program_client::nonce + 1))
-                .returning((program_client::id, program_client::nonce))
-                .get_result(conn)
-                .await?;
-
-            integrity::sign_entity(
-                conn,
-                &keyholder,
-                &ClientCredentials {
-                    pubkey: pubkey.clone(),
-                    nonce: new_nonce,
-                },
-                id,
-            )
-            .await
-            .map_err(|e| {
-                error!(?e, "Integrity sign failed after nonce update");
-                Error::DatabaseOperationFailed
-            })?;
-
-            Ok(new_nonce)
-        })
-    })
-    .await
-}
-
-async fn approve_new_client(
-    actors: &crate::actors::GlobalActors,
-    profile: ClientProfile,
-) -> Result<(), Error> {
+async fn approve_new_client(actors: &GlobalActors, profile: ClientProfile) -> Result<(), Error> {
     let result = actors
         .flow_coordinator
         .ask(RequestClientApproval { client: profile })
@@ -212,11 +157,12 @@ async fn approve_new_client(
 
 async fn insert_client(
     db: &db::DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
     pubkey: &authn::PublicKey,
     metadata: &ClientMetadata,
 ) -> Result<i32, Error> {
-    use crate::db::schema::{client_metadata, program_client};
+    use crate::db::schema::client_metadata;
+
     let pubkey = pubkey.clone();
     let metadata = metadata.clone();
 
@@ -226,11 +172,9 @@ async fn insert_client(
     })?;
 
     conn.exclusive_transaction(|conn| {
-        let keyholder = keyholder.clone();
+        let vault = vault.clone();
         let pubkey = pubkey.clone();
         Box::pin(async move {
-            const NONCE_START: i32 = 1;
-
             let metadata_id = insert_into(client_metadata::table)
                 .values((
                     client_metadata::name.eq(&metadata.name),
@@ -245,7 +189,6 @@ async fn insert_client(
                 .values((
                     program_client::public_key.eq(pubkey.to_bytes()),
                     program_client::metadata_id.eq(metadata_id),
-                    program_client::nonce.eq(NONCE_START),
                 ))
                 .on_conflict_do_nothing()
                 .returning(program_client::id)
@@ -254,10 +197,9 @@ async fn insert_client(
 
             integrity::sign_entity(
                 conn,
-                &keyholder,
+                &vault,
                 &ClientCredentials {
                     pubkey: pubkey.clone(),
-                    nonce: NONCE_START,
                 },
                 client_id,
             )
@@ -347,15 +289,14 @@ async fn sync_client_metadata(
 async fn challenge_client<T>(
     transport: &mut T,
     pubkey: authn::PublicKey,
-    nonce: i32,
+    challenge: AuthChallenge,
 ) -> Result<(), Error>
 where
     T: Bi<Inbound, Result<Outbound, Error>> + ?Sized,
 {
     transport
         .send(Ok(Outbound::AuthChallenge {
-            pubkey: pubkey.clone(),
-            nonce,
+            challenge: challenge.clone(),
         }))
         .await
         .map_err(|e| {
@@ -373,7 +314,7 @@ where
         Error::Transport
     })?;
 
-    if !pubkey.verify(nonce, CLIENT_CONTEXT, &signature) {
+    if !pubkey.verify(&challenge, CLIENT_CONTEXT, &signature) {
         error!("Challenge solution verification failed");
         return Err(Error::InvalidChallengeSolution);
     }
@@ -389,12 +330,10 @@ where
         return Err(Error::Transport);
     };
 
-    let client_id = match get_current_nonce_and_id(&props.db, &pubkey).await? {
-        Some((id, _)) => {
-            verify_integrity(&props.db, &props.actors.key_holder, &pubkey).await?;
+    let client_id = if let Some(id) = get_client_id(&props.db, &pubkey).await? {
+        verify_integrity(&props.db, &props.actors.vault, &pubkey).await?;
         id
-        }
-        None => {
+    } else {
         approve_new_client(
             &props.actors,
             ClientProfile {
@@ -403,13 +342,13 @@ where
             },
         )
         .await?;
-            insert_client(&props.db, &props.actors.key_holder, &pubkey, &metadata).await?
-        }
+        insert_client(&props.db, &props.actors.vault, &pubkey, &metadata).await?
     };
 
     sync_client_metadata(&props.db, client_id, &metadata).await?;
-    let challenge_nonce = create_nonce(&props.db, &props.actors.key_holder, &pubkey).await?;
-    challenge_client(transport, pubkey, challenge_nonce).await?;
+
+    let challenge = AuthChallenge::generate(&mut rand::rng());
+    challenge_client(transport, pubkey, challenge).await?;
 
     transport
         .send(Ok(Outbound::AuthSuccess))

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

@@ -1,24 +1,22 @@
+use crate::{
+    actors::GlobalActors, crypto::integrity::Integrable, db, peers::client::session::ClientSession,
+};
 use arbiter_crypto::authn;
+use arbiter_macros::Hashable;
 use arbiter_proto::{ClientMetadata, transport::Bi};
+
 use kameo::actor::Spawn;
 use tracing::{error, info};
 
-use crate::{
-    actors::{GlobalActors, client::session::ClientSession},
-    crypto::integrity::Integrable,
-    db,
-};
-
 #[derive(Debug, Clone)]
 pub struct ClientProfile {
     pub pubkey: authn::PublicKey,
     pub metadata: ClientMetadata,
 }
 
-#[derive(arbiter_macros::Hashable)]
+#[derive(Hashable)]
 pub struct ClientCredentials {
     pub pubkey: authn::PublicKey,
-    pub nonce: i32,
 }
 
 impl Integrable for ClientCredentials {
@@ -31,7 +29,7 @@ pub struct ClientConnection {
 }
 
 impl ClientConnection {
-    pub fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
+    pub const fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
         Self { db, actors }
     }
 }
@@ -44,7 +42,7 @@ where
     T: Bi<auth::Inbound, Result<auth::Outbound, auth::Error>> + Send + ?Sized,
 {
     let fut = auth::authenticate(&mut props, transport);
-    println!("authenticate future size: {}", std::mem::size_of_val(&fut));
+    println!("authenticate future size: {}", size_of_val(&fut));
     match fut.await {
         Ok(client_id) => {
             ClientSession::spawn(ClientSession::new(props, client_id));

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

@@ -1,27 +1,26 @@
-use kameo::{Actor, messages};
-use tracing::error;
-
-use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
-
+use super::ClientConnection;
 use crate::{
     actors::{
         GlobalActors,
-        client::ClientConnection,
         evm::{ClientSignTransaction, SignTransactionError},
         flow_coordinator::RegisterClient,
-        keyholder::KeyHolderState,
+        vault::VaultState,
     },
     db,
     evm::VetError,
 };
 
+use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
+use kameo::{Actor, messages};
+use tracing::error;
+
 pub struct ClientSession {
     props: ClientConnection,
     client_id: i32,
 }
 
 impl ClientSession {
-    pub(crate) fn new(props: ClientConnection, client_id: i32) -> Self {
+    pub(crate) const fn new(props: ClientConnection, client_id: i32) -> Self {
         Self { props, client_id }
     }
 }
@@ -29,13 +28,13 @@ impl ClientSession {
 #[messages]
 impl ClientSession {
     #[message]
-    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<KeyHolderState, Error> {
-        use crate::actors::keyholder::GetState;
+    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<VaultState, Error> {
+        use crate::actors::vault::GetState;
 
-        let vault_state = match self.props.actors.key_holder.ask(GetState {}).await {
+        let vault_state = match self.props.actors.vault.ask(GetState {}).await {
             Ok(state) => state,
             Err(err) => {
-                error!(?err, actor = "client", "keyholder.query.failed");
+                error!(?err, actor = "client", "vault.query.failed");
                 return Err(Error::Internal);
             }
         };
@@ -92,7 +91,7 @@ impl Actor for ClientSession {
 }
 
 impl ClientSession {
-    pub fn new_test(db: db::DatabasePool, actors: GlobalActors) -> Self {
+    pub const fn new_test(db: db::DatabasePool, actors: GlobalActors) -> Self {
         let props = ClientConnection::new(db, actors);
         Self {
             props,

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

@@ -0,0 +1,2 @@
+pub mod client;
+pub mod user_agent;

server/crates/arbiter-server/src/peers/user_agent/auth/mod.rs

@@ -1,13 +1,14 @@
-use arbiter_crypto::authn;
+use super::{Credentials, UserAgentConnection};
+use arbiter_crypto::authn::{self, AuthChallenge};
 use arbiter_proto::transport::Bi;
+
+use state::{
+    AuthContext, AuthError, AuthEvents, AuthStateMachine, AuthStates, ChallengeRequest,
+    ChallengeSolution,
+};
 use tracing::error;
 
-use crate::actors::user_agent::{
-    UserAgentConnection,
-    auth::state::{AuthContext, AuthStateMachine},
-};
 mod state;
-use state::*;
 
 #[derive(Debug, Clone)]
 pub enum Inbound {
@@ -46,7 +47,7 @@ impl From<diesel::result::Error> for Error {
 
 #[derive(Debug, Clone)]
 pub enum Outbound {
-    AuthChallenge { nonce: i32 },
+    AuthChallenge { challenge: AuthChallenge },
     AuthSuccess,
 }
 
@@ -54,12 +55,11 @@ fn parse_auth_event(payload: Inbound) -> AuthEvents {
     match payload {
         Inbound::AuthChallengeRequest {
             pubkey,
-            bootstrap_token: None,
-        } => AuthEvents::AuthRequest(ChallengeRequest { pubkey }),
-        Inbound::AuthChallengeRequest {
+            bootstrap_token,
+        } => AuthEvents::AuthRequest(ChallengeRequest {
             pubkey,
-            bootstrap_token: Some(token),
-        } => AuthEvents::BootstrapAuthRequest(BootstrapAuthRequest { pubkey, token }),
+            bootstrap_token,
+        }),
         Inbound::AuthChallengeSolution { signature } => {
             AuthEvents::ReceivedSolution(ChallengeSolution {
                 solution: signature,
@@ -70,21 +70,20 @@ fn parse_auth_event(payload: Inbound) -> AuthEvents {
 
 pub async fn authenticate<T>(
     props: &mut UserAgentConnection,
-    transport: T,
-) -> Result<authn::PublicKey, Error>
+    transport: &mut T,
+) -> Result<Credentials, Error>
 where
-    T: Bi<Inbound, Result<Outbound, Error>> + Send,
+    T: Bi<Inbound, Result<Outbound, Error>> + Send + ?Sized,
 {
     let mut state = AuthStateMachine::new(AuthContext::new(props, transport));
 
     loop {
-        // `state` holds a mutable reference to `props` so we can't access it directly here
         let Some(payload) = state.context_mut().transport.recv().await else {
             return Err(Error::Transport);
         };
 
         match state.process_event(parse_auth_event(payload)).await {
-            Ok(AuthStates::AuthOk(key)) => return Ok(key.clone()),
+            Ok(AuthStates::AuthOk(result)) => return Ok(result.clone()),
             Err(AuthError::ActionFailed(err)) => {
                 error!(?err, "State machine action failed");
                 return Err(err);

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

@@ -0,0 +1,198 @@
+use super::{
+    super::{Credentials, UserAgentConnection},
+    Error,
+};
+use crate::{
+    actors::bootstrap::ConsumeToken,
+    db::{DatabasePool, schema::useragent_client},
+    peers::user_agent::auth::Outbound,
+};
+use arbiter_crypto::authn::{self, AuthChallenge, USERAGENT_CONTEXT};
+use arbiter_proto::transport::Bi;
+
+use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl};
+use diesel_async::RunQueryDsl;
+use tracing::error;
+
+pub(super) struct ChallengeRequest {
+    pub(super) pubkey: authn::PublicKey,
+    pub(super) bootstrap_token: Option<String>,
+}
+
+pub(super) struct ChallengeContext {
+    pub(super) challenge: AuthChallenge,
+    pub(super) pubkey: authn::PublicKey,
+    pub(super) bootstrap_token: Option<String>,
+}
+
+pub(super) struct ChallengeSolution {
+    pub(super) solution: Vec<u8>,
+}
+
+smlang::statemachine!(
+    name: Auth,
+    custom_error: true,
+    transitions: {
+        *Init + AuthRequest(ChallengeRequest) / async prepare_challenge = SentChallenge(ChallengeContext),
+        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) / async verify_solution = AuthOk(Credentials),
+    }
+);
+
+async fn get_client_id(db: &DatabasePool, pubkey: &authn::PublicKey) -> Result<Option<i32>, Error> {
+    let mut conn = db.get().await.map_err(|e| {
+        error!(error = ?e, "Database pool error");
+        Error::internal("Database unavailable")
+    })?;
+
+    useragent_client::table
+        .filter(useragent_client::public_key.eq(pubkey.to_bytes()))
+        .select(useragent_client::id)
+        .first::<i32>(&mut conn)
+        .await
+        .optional()
+        .map_err(|e| {
+            error!(error = ?e, "Database error");
+            Error::internal("Database operation failed")
+        })
+}
+
+async fn register_key(db: &DatabasePool, pubkey: &authn::PublicKey) -> Result<i32, Error> {
+    let pubkey_bytes = pubkey.to_bytes();
+    let mut conn = db.get().await.map_err(|e| {
+        error!(error = ?e, "Database pool error");
+        Error::internal("Database unavailable")
+    })?;
+
+    let id: i32 = diesel::insert_into(useragent_client::table)
+        .values((useragent_client::public_key.eq(pubkey_bytes),))
+        .returning(useragent_client::id)
+        .get_result(&mut conn)
+        .await
+        .map_err(|e| {
+            error!(error = ?e, "Database error");
+            Error::internal("Database operation failed")
+        })?;
+
+    Ok(id)
+}
+
+pub(super) struct AuthContext<'a, T: ?Sized> {
+    pub(super) conn: &'a mut UserAgentConnection,
+    pub(super) transport: &'a mut T,
+}
+
+impl<'a, T: ?Sized> AuthContext<'a, T> {
+    pub(super) const fn new(conn: &'a mut UserAgentConnection, transport: &'a mut T) -> Self {
+        Self { conn, transport }
+    }
+}
+
+impl<T> AuthStateMachineContext for AuthContext<'_, T>
+where
+    T: Bi<super::Inbound, Result<Outbound, Error>> + Send + ?Sized,
+{
+    type Error = Error;
+
+    async fn prepare_challenge(
+        &mut self,
+        ChallengeRequest {
+            pubkey,
+            bootstrap_token,
+        }: ChallengeRequest,
+    ) -> Result<ChallengeContext, Self::Error> {
+        // Verify pubkey is registered (unless bootstrapping)
+        if bootstrap_token.is_none() {
+            let id = get_client_id(&self.conn.db, &pubkey).await?;
+            if id.is_none() {
+                return Err(Error::UnregisteredPublicKey);
+            }
+        }
+
+        let challenge = AuthChallenge::generate(&mut rand::rng());
+
+        self.transport
+            .send(Ok(Outbound::AuthChallenge {
+                challenge: challenge.clone(),
+            }))
+            .await
+            .map_err(|e| {
+                error!(?e, "Failed to send auth challenge");
+                Error::Transport
+            })?;
+
+        Ok(ChallengeContext {
+            challenge,
+            pubkey,
+            bootstrap_token,
+        })
+    }
+
+    #[allow(missing_docs)]
+    #[allow(clippy::unused_unit)]
+    async fn verify_solution(
+        &mut self,
+        ChallengeContext {
+            challenge,
+            pubkey,
+            bootstrap_token,
+        }: &ChallengeContext,
+        ChallengeSolution { solution }: ChallengeSolution,
+    ) -> Result<Credentials, Self::Error> {
+        let signature = authn::Signature::try_from(solution.as_slice()).map_err(|()| {
+            error!("Failed to decode signature in challenge solution");
+            Error::InvalidChallengeSolution
+        })?;
+
+        let valid = pubkey.verify(challenge, USERAGENT_CONTEXT, &signature);
+
+        if !valid {
+            self.transport
+                .send(Err(Error::InvalidChallengeSolution))
+                .await
+                .map_err(|_| Error::Transport)?;
+            return Err(Error::InvalidChallengeSolution);
+        }
+
+        // Resolve client id: bootstrap (consume token + register) or lookup
+        let id = match bootstrap_token {
+            Some(token) => {
+                let token_ok: bool = self
+                    .conn
+                    .actors
+                    .bootstrapper
+                    .ask(ConsumeToken {
+                        token: token.clone(),
+                    })
+                    .await
+                    .map_err(|e| {
+                        error!(?e, "Failed to consume bootstrap token");
+                        Error::internal("Failed to consume bootstrap token")
+                    })?;
+
+                if !token_ok {
+                    error!("Invalid bootstrap token provided");
+                    self.transport
+                        .send(Err(Error::InvalidBootstrapToken))
+                        .await
+                        .map_err(|_| Error::Transport)?;
+                    return Err(Error::InvalidBootstrapToken);
+                }
+
+                register_key(&self.conn.db, pubkey).await?
+            }
+            None => get_client_id(&self.conn.db, pubkey)
+                .await?
+                .ok_or(Error::UnregisteredPublicKey)?,
+        };
+
+        self.transport
+            .send(Ok(Outbound::AuthSuccess))
+            .await
+            .map_err(|_| Error::Transport)?;
+
+        Ok(Credentials {
+            id,
+            pubkey: pubkey.clone(),
+        })
+    }
+}

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

@@ -0,0 +1,185 @@
+use crate::{
+    actors::{
+        GlobalActors,
+        vault::{GetState, Vault},
+    },
+    crypto::integrity::{self, AttestationStatus, Integrable},
+    db::{DatabaseError, DatabasePool},
+    peers::client::ClientProfile,
+};
+use arbiter_crypto::authn;
+use arbiter_macros::Hashable;
+use arbiter_proto::transport::{Bi, Sender};
+use vault_gate::VaultGate;
+
+use kameo::actor::{ActorRef, Spawn as _};
+use tokio::sync::oneshot;
+use tracing::{error, warn};
+
+pub use auth::authenticate;
+pub use session::UserAgentSession;
+
+pub mod auth;
+pub mod session;
+pub mod vault_gate;
+
+#[derive(Debug, Clone, Hashable)]
+pub struct Credentials {
+    pub id: i32,
+    pub pubkey: authn::PublicKey,
+}
+
+impl Integrable for Credentials {
+    const KIND: &'static str = "useragent_credentials";
+}
+
+// Messages, sent by user agent to connection client without having a request
+#[derive(Debug)]
+pub enum OutOfBand {
+    ClientConnectionRequest { profile: ClientProfile },
+    ClientConnectionCancel { pubkey: authn::PublicKey },
+}
+
+#[derive(Clone)]
+pub struct UserAgentConnection {
+    pub(crate) db: DatabasePool,
+    pub(crate) actors: GlobalActors,
+}
+
+impl UserAgentConnection {
+    pub const fn new(db: DatabasePool, actors: GlobalActors) -> Self {
+        Self { db, actors }
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("authentication failed: {0:?}")]
+    Auth(auth::Error),
+    #[error("vault gate failed: {0}")]
+    VaultGate(#[from] vault_gate::Error),
+    #[error("transport closed unexpectedly")]
+    Transport,
+    #[error("database error: {0}")]
+    Database(DatabaseError),
+    #[error("internal: {0}")]
+    Internal(String),
+}
+
+impl From<auth::Error> for Error {
+    fn from(err: auth::Error) -> Self {
+        Self::Auth(err)
+    }
+}
+
+async fn verify_integrity(
+    db: &DatabasePool,
+    vault: &ActorRef<Vault>,
+    credentials: &Credentials,
+) -> Result<(), Error> {
+    let mut conn = db
+        .get()
+        .await
+        .map_err(|_| Error::Internal("DB unavailable".into()))?;
+    match integrity::verify_entity(&mut conn, vault, credentials, credentials.id).await {
+        Ok(AttestationStatus::Attested) => Ok(()),
+        Ok(AttestationStatus::Unavailable) => {
+            Err(Error::Internal("Vault sealed during promotion".into()))
+        }
+        Err(e) => {
+            error!(?e, "Integrity verification failed during unseal promotion");
+            Err(Error::Internal("Integrity check failed".into()))
+        }
+    }
+}
+
+async fn should_run_gate(vault: &ActorRef<Vault>) -> Result<bool, Error> {
+    let vault_state = vault
+        .ask(GetState {})
+        .await
+        .map_err(|_| Error::Internal("Failed to contact the vault".into()))?;
+
+    Ok(!matches!(
+        vault_state,
+        crate::actors::vault::VaultState::Unsealed
+    ))
+}
+
+async fn run_vault_gate<T>(
+    props: &UserAgentConnection,
+    transport: &mut T,
+    auth_creds: Credentials,
+) -> Result<(), Error>
+where
+    T: Bi<vault_gate::Inbound, Result<vault_gate::Outbound, vault_gate::Error>> + Send + ?Sized,
+{
+    let (promotion_tx, mut promotion_rx) = oneshot::channel();
+    let gate = VaultGate::spawn(VaultGate::new(
+        auth_creds,
+        props.actors.clone(),
+        props.db.clone(),
+        promotion_tx,
+    ));
+
+    let result = loop {
+        tokio::select! {
+            promotion = &mut promotion_rx => {
+                break match promotion {
+                    Ok(Ok(creds)) => Ok(creds),
+                    Ok(Err(err)) => Err(Error::VaultGate(err)),
+                    Err(_) => Err(Error::Internal(
+                        "vault gate promotion channel closed".into(),
+                    )),
+                };
+            }
+
+            inbound = transport.recv() => {
+                let Some(inbound) = inbound else {
+                    break Err(Error::Transport);
+                };
+
+                match gate.ask(inbound).await {
+                    Ok(outbound) => {
+                        if transport.send(Ok(outbound)).await.is_err() {
+                            break Err(Error::Transport);
+                        }
+                    }
+                    Err(err) => {
+                        warn!(?err, "VaultGate failed to handle message");
+                        break Err(Error::Internal(format!(
+                            "vault gate ask failed: {err:?}"
+                        )));
+                    }
+                }
+            }
+        }
+    };
+
+    gate.kill();
+    result
+}
+
+pub async fn start<T>(
+    props: &mut UserAgentConnection,
+    mut transport: T,
+    oob_sender: Box<dyn Sender<OutOfBand>>,
+) -> Result<ActorRef<UserAgentSession>, Error>
+where
+    T: Bi<auth::Inbound, Result<auth::Outbound, auth::Error>> + Send,
+    T: Bi<vault_gate::Inbound, Result<vault_gate::Outbound, vault_gate::Error>> + Send,
+{
+    let creds = authenticate(props, &mut transport).await?;
+
+    // should run vault gate only if sealed / unbootstrapped
+    if should_run_gate(&props.actors.vault).await? {
+        run_vault_gate(props, &mut transport, creds.clone()).await?;
+    }
+
+    // checking the integrity
+    verify_integrity(&props.db, &props.actors.vault, &creds).await?;
+
+    Ok(UserAgentSession::spawn(UserAgentSession::new(
+        props.clone(),
+        oob_sender,
+    )))
+}

server/crates/arbiter-server/src/peers/user_agent/session/handlers.rs

@@ -0,0 +1,278 @@
+use super::{Error, UserAgentSession};
+use crate::{
+    actors::evm::{
+        ClientSignTransaction, Generate, ListWallets, SignTransactionError as EvmSignError,
+        UseragentCreateGrant, UseragentListGrants,
+    },
+    actors::flow_coordinator::client_connect_approval::ClientApprovalAnswer,
+    actors::vault::VaultState,
+    db::models::{EvmWalletAccess, NewEvmWalletAccess, ProgramClient, ProgramClientMetadata},
+    evm::policies::{Grant, SpecificGrant},
+};
+use arbiter_crypto::authn;
+
+use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
+use diesel::{ExpressionMethods as _, QueryDsl as _, SelectableHelper};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use kameo::{error::SendError, messages, prelude::Context};
+use tracing::error;
+
+#[derive(Debug, Error)]
+pub enum SignTransactionError {
+    #[error("Policy evaluation failed")]
+    Vet(#[from] crate::evm::VetError),
+
+    #[error("Internal signing error")]
+    Internal,
+}
+
+#[derive(Debug, Error)]
+pub enum GrantMutationError {
+    #[error("Vault is sealed")]
+    VaultSealed,
+
+    #[error("Internal grant mutation error")]
+    Internal,
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message]
+    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<VaultState, Error> {
+        use crate::actors::vault::GetState;
+
+        let vault_state = match self.props.actors.vault.ask(GetState {}).await {
+            Ok(state) => state,
+            Err(err) => {
+                error!(?err, actor = "useragent", "vault.query.failed");
+                return Err(Error::internal("Vault is in broken state"));
+            }
+        };
+
+        Ok(vault_state)
+    }
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message]
+    pub(crate) async fn handle_evm_wallet_create(&mut self) -> Result<(i32, Address), Error> {
+        match self.props.actors.evm.ask(Generate {}).await {
+            Ok(address) => Ok(address),
+            Err(SendError::HandlerError(err)) => Err(Error::internal(format!(
+                "EVM wallet generation failed: {err}"
+            ))),
+            Err(err) => {
+                error!(?err, "EVM actor unreachable during wallet create");
+                Err(Error::internal("EVM actor unreachable"))
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_evm_wallet_list(&mut self) -> Result<Vec<(i32, Address)>, Error> {
+        match self.props.actors.evm.ask(ListWallets {}).await {
+            Ok(wallets) => Ok(wallets),
+            Err(err) => {
+                error!(?err, "EVM wallet list failed");
+                Err(Error::internal("Failed to list EVM wallets"))
+            }
+        }
+    }
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message]
+    pub(crate) async fn handle_grant_list(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
+        match self.props.actors.evm.ask(UseragentListGrants {}).await {
+            Ok(grants) => Ok(grants),
+            Err(err) => {
+                error!(?err, "EVM grant list failed");
+                Err(Error::internal("Failed to list EVM grants"))
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_grant_create(
+        &mut self,
+        basic: crate::evm::policies::SharedGrantSettings,
+        grant: SpecificGrant,
+    ) -> Result<i32, GrantMutationError> {
+        match self
+            .props
+            .actors
+            .evm
+            .ask(UseragentCreateGrant { basic, grant })
+            .await
+        {
+            Ok(grant_id) => Ok(grant_id),
+            Err(err) => {
+                error!(?err, "EVM grant create failed");
+                Err(GrantMutationError::Internal)
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) fn handle_grant_delete(&mut self, grant_id: i32) -> Result<(), GrantMutationError> {
+        // match self
+        //     .props
+        //     .actors
+        //     .evm
+        //     .ask(UseragentDeleteGrant { grant_id })
+        //     .await
+        // {
+        //     Ok(()) => Ok(()),
+        //     Err(err) => {
+        //         error!(?err, "EVM grant delete failed");
+        //         Err(GrantMutationError::Internal)
+        //     }
+        // }
+        let _ = grant_id;
+        todo!()
+    }
+
+    #[message]
+    pub(crate) async fn handle_sign_transaction(
+        &mut self,
+        client_id: i32,
+        wallet_address: Address,
+        transaction: TxEip1559,
+    ) -> Result<Signature, SignTransactionError> {
+        match self
+            .props
+            .actors
+            .evm
+            .ask(ClientSignTransaction {
+                client_id,
+                wallet_address,
+                transaction,
+            })
+            .await
+        {
+            Ok(signature) => Ok(signature),
+            Err(SendError::HandlerError(EvmSignError::Vet(vet_error))) => {
+                Err(SignTransactionError::Vet(vet_error))
+            }
+            Err(err) => {
+                error!(?err, "EVM sign transaction failed in user-agent session");
+                Err(SignTransactionError::Internal)
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_grant_evm_wallet_access(
+        &mut self,
+        entries: Vec<NewEvmWalletAccess>,
+    ) -> Result<(), Error> {
+        let mut conn = self.props.db.get().await?;
+        conn.transaction(|conn| {
+            Box::pin(async move {
+                use crate::db::schema::evm_wallet_access;
+
+                for entry in entries {
+                    diesel::insert_into(evm_wallet_access::table)
+                        .values(&entry)
+                        .on_conflict_do_nothing()
+                        .execute(conn)
+                        .await?;
+                }
+
+                Result::<_, Error>::Ok(())
+            })
+        })
+        .await?;
+        Ok(())
+    }
+
+    #[message]
+    pub(crate) async fn handle_revoke_evm_wallet_access(
+        &mut self,
+        entries: Vec<i32>,
+    ) -> Result<(), Error> {
+        let mut conn = self.props.db.get().await?;
+        conn.transaction(|conn| {
+            Box::pin(async move {
+                use crate::db::schema::evm_wallet_access;
+                for entry in entries {
+                    diesel::delete(evm_wallet_access::table)
+                        .filter(evm_wallet_access::wallet_id.eq(entry))
+                        .execute(conn)
+                        .await?;
+                }
+
+                Result::<_, Error>::Ok(())
+            })
+        })
+        .await?;
+        Ok(())
+    }
+
+    #[message]
+    pub(crate) async fn handle_list_wallet_access(
+        &mut self,
+    ) -> Result<Vec<EvmWalletAccess>, Error> {
+        let mut conn = self.props.db.get().await?;
+        use crate::db::schema::evm_wallet_access;
+        let access_entries = evm_wallet_access::table
+            .select(EvmWalletAccess::as_select())
+            .load::<_>(&mut conn)
+            .await?;
+        Ok(access_entries)
+    }
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message(ctx)]
+    pub(crate) async fn handle_new_client_approve(
+        &mut self,
+        approved: bool,
+        pubkey: authn::PublicKey,
+        ctx: &mut Context<Self, Result<(), Error>>,
+    ) -> Result<(), Error> {
+        let Some(pending_approval) = self.pending_client_approvals.remove(&pubkey.to_bytes())
+        else {
+            error!("Received client connection response for unknown client");
+            return Err(Error::internal("Unknown client in connection response"));
+        };
+
+        pending_approval
+            .controller
+            .tell(ClientApprovalAnswer { approved })
+            .await
+            .map_err(|err| {
+                error!(
+                    ?err,
+                    "Failed to send client approval response to controller"
+                );
+                Error::internal("Failed to send client approval response to controller")
+            })?;
+
+        ctx.actor_ref().unlink(&pending_approval.controller).await;
+
+        Ok(())
+    }
+
+    #[message]
+    pub(crate) async fn handle_sdk_client_list(
+        &mut self,
+    ) -> Result<Vec<(ProgramClient, ProgramClientMetadata)>, Error> {
+        use crate::db::schema::{client_metadata, program_client};
+        let mut conn = self.props.db.get().await?;
+
+        let clients = program_client::table
+            .inner_join(client_metadata::table)
+            .select((
+                ProgramClient::as_select(),
+                ProgramClientMetadata::as_select(),
+            ))
+            .load::<(ProgramClient, ProgramClientMetadata)>(&mut conn)
+            .await?;
+
+        Ok(clients)
+    }
+}

server/crates/arbiter-server/src/peers/user_agent/session/mod.rs

@@ -1,21 +1,19 @@
+use super::{OutOfBand, UserAgentConnection};
+use crate::{
+    actors::{
+        flow_coordinator::client_connect_approval::ClientApprovalController,
+        useragent_registry::ConnectUseragent,
+    },
+    peers::client::ClientProfile,
+};
 use arbiter_crypto::authn;
-
-use std::{borrow::Cow, collections::HashMap};
-
 use arbiter_proto::transport::Sender;
-use async_trait::async_trait;
+
 use kameo::{Actor, actor::ActorRef, messages};
+use std::{borrow::Cow, collections::HashMap};
 use thiserror::Error;
 use tracing::error;
 
-use crate::actors::{
-    client::ClientProfile,
-    flow_coordinator::{RegisterUserAgent, client_connect_approval::ClientApprovalController},
-    user_agent::{OutOfBand, UserAgentConnection},
-};
-mod state;
-use state::{DummyContext, UserAgentEvents, UserAgentStateMachine};
-
 #[derive(Debug, Error)]
 pub enum Error {
     #[error("State transition failed")]
@@ -53,47 +51,21 @@ pub struct PendingClientApproval {
 
 pub struct UserAgentSession {
     props: UserAgentConnection,
-    state: UserAgentStateMachine<DummyContext>,
     sender: Box<dyn Sender<OutOfBand>>,
 
     pending_client_approvals: HashMap<Vec<u8>, PendingClientApproval>,
 }
 
-pub mod connection;
+pub mod handlers;
 
 impl UserAgentSession {
     pub(crate) fn new(props: UserAgentConnection, sender: Box<dyn Sender<OutOfBand>>) -> Self {
         Self {
             props,
-            state: UserAgentStateMachine::new(DummyContext),
             sender,
             pending_client_approvals: Default::default(),
         }
     }
-
-    pub fn new_test(db: crate::db::DatabasePool, actors: crate::actors::GlobalActors) -> Self {
-        struct DummySender;
-
-        #[async_trait]
-        impl Sender<OutOfBand> for DummySender {
-            async fn send(
-                &mut self,
-                _item: OutOfBand,
-            ) -> Result<(), arbiter_proto::transport::Error> {
-                Ok(())
-            }
-        }
-
-        Self::new(UserAgentConnection::new(db, actors), Box::new(DummySender))
-    }
-
-    fn transition(&mut self, event: UserAgentEvents) -> Result<(), Error> {
-        self.state.process_event(event).map_err(|e| {
-            error!(?e, "State transition failed");
-            Error::State
-        })?;
-        Ok(())
-    }
 }
 
 #[messages]
@@ -134,23 +106,20 @@ impl Actor for UserAgentSession {
 
     type Error = Error;
 
-    async fn on_start(
-        args: Self::Args,
-        this: kameo::prelude::ActorRef<Self>,
-    ) -> Result<Self, Self::Error> {
+    async fn on_start(args: Self::Args, this: ActorRef<Self>) -> Result<Self, Self::Error> {
         args.props
             .actors
-            .flow_coordinator
-            .ask(RegisterUserAgent {
+            .useragent_registry
+            .ask(ConnectUseragent {
                 actor: this.clone(),
             })
             .await
             .map_err(|err| {
                 error!(
                     ?err,
-                    "Failed to register user agent connection with flow coordinator"
+                    "Failed to register user agent connection with user agent registry"
                 );
-                Error::internal("Failed to register user agent connection with flow coordinator")
+                Error::internal("Failed to register user agent connection with user agent registry")
             })?;
         Ok(args)
     }

server/crates/arbiter-server/src/peers/user_agent/vault_gate/mod.rs

@@ -0,0 +1,288 @@
+use super::Credentials;
+use crate::{
+    actors::{
+        GlobalActors,
+        vault::{self, Bootstrap, GetState, TryUnseal, VaultState, events},
+    },
+    crypto::integrity::{self},
+    db::DatabasePool,
+};
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use state::State;
+
+use chacha20poly1305::{AeadInPlace, KeyInit as _, XChaCha20Poly1305, XNonce};
+use kameo::{Actor, error::SendError, messages, prelude::Message};
+use kameo_actors::message_bus::Register;
+use tokio::sync::oneshot;
+use tracing::{error, info};
+use x25519_dalek::{EphemeralSecret, PublicKey, SharedSecret};
+
+pub mod state;
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("Vault is already bootstrapped")]
+    AlreadyBootstrapped,
+    #[error("Invalid key provided")]
+    InvalidKey,
+
+    #[error("State transition failed")]
+    State,
+
+    #[error("Internal error: {0}")]
+    Internal(String),
+}
+impl Error {
+    fn internal(message: impl Into<String>) -> Self {
+        Self::Internal(message.into())
+    }
+}
+
+pub struct HandshakeResponse {
+    pub server_pubkey: PublicKey,
+}
+
+pub struct VaultGate {
+    pub auth_creds: Credentials,
+    pub promotion_tx: Option<oneshot::Sender<Result<(), Error>>>,
+    pub state: State,
+    pub actors: GlobalActors,
+    pub db: DatabasePool,
+}
+
+impl VaultGate {
+    pub fn new(
+        auth_creds: Credentials,
+        actors: GlobalActors,
+        db: DatabasePool,
+        promotion_tx: oneshot::Sender<Result<(), Error>>,
+    ) -> Self {
+        Self {
+            auth_creds,
+            state: State::default(),
+            actors,
+            db,
+            promotion_tx: Some(promotion_tx),
+        }
+    }
+}
+
+impl Actor for VaultGate {
+    type Args = Self;
+
+    type Error = ();
+
+    async fn on_start(
+        args: Self::Args,
+        actor_ref: kameo::prelude::ActorRef<Self>,
+    ) -> Result<Self, Self::Error> {
+        let _ = args
+            .actors
+            .events
+            .tell(Register(
+                actor_ref.clone().recipient::<events::Bootstrapped>(),
+            ))
+            .await;
+        let _ = args
+            .actors
+            .events
+            .tell(Register(actor_ref.recipient::<events::Unsealed>()))
+            .await;
+        Ok(args)
+    }
+}
+
+impl VaultGate {
+    fn decrypt_key(
+        secret: &SharedSecret,
+        nonce: &[u8],
+        ciphertext: &[u8],
+        associated_data: &[u8],
+    ) -> Result<SafeCell<Vec<u8>>, ()> {
+        let nonce = XNonce::from_slice(nonce);
+
+        let cipher = XChaCha20Poly1305::new(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(())
+            }
+        }
+    }
+}
+
+#[messages(messages = Inbound, replies = Outbound)]
+impl VaultGate {
+    #[message]
+    pub fn handle_handshake(
+        &mut self,
+        client_pubkey: PublicKey,
+    ) -> Result<HandshakeResponse, Error> {
+        let ephemeral_secret = EphemeralSecret::random();
+        let public_key = PublicKey::from(&ephemeral_secret);
+
+        let secret = ephemeral_secret.diffie_hellman(&client_pubkey);
+
+        self.state = State::ReadyForExchange {
+            server_key: public_key,
+            secret,
+        };
+
+        Ok(HandshakeResponse {
+            server_pubkey: public_key,
+        })
+    }
+
+    #[message]
+    pub async fn handle_unseal_encrypted_key(
+        &mut self,
+        nonce: Vec<u8>,
+        ciphertext: Vec<u8>,
+        associated_data: Vec<u8>,
+    ) -> Result<(), Error> {
+        let State::ReadyForExchange { secret, .. } = &self.state else {
+            return Err(Error::State);
+        };
+
+        let Ok(seal_key_buffer) = Self::decrypt_key(secret, &nonce, &ciphertext, &associated_data)
+        else {
+            return Err(Error::InvalidKey);
+        };
+
+        match self
+            .actors
+            .vault
+            .ask(TryUnseal {
+                seal_key_raw: seal_key_buffer,
+            })
+            .await
+        {
+            Ok(()) => {
+                info!("Successfully unsealed key with client-provided key");
+                Ok(())
+            }
+            Err(SendError::HandlerError(vault::Error::InvalidKey)) => Err(Error::InvalidKey),
+            Err(SendError::HandlerError(err)) => {
+                error!(?err, "Vault failed to unseal key");
+                Err(Error::InvalidKey)
+            }
+            Err(err) => {
+                error!(?err, "Failed to send unseal request to vault");
+                Err(Error::internal("Vault actor error"))
+            }
+        }
+    }
+
+    #[message]
+    pub async fn handle_bootstrap_encrypted_key(
+        &mut self,
+        nonce: Vec<u8>,
+        ciphertext: Vec<u8>,
+        associated_data: Vec<u8>,
+    ) -> Result<(), Error> {
+        let State::ReadyForExchange { secret, .. } = &self.state else {
+            return Err(Error::State);
+        };
+
+        let Ok(seal_key_buffer) = Self::decrypt_key(secret, &nonce, &ciphertext, &associated_data)
+        else {
+            return Err(Error::InvalidKey);
+        };
+
+        match self
+            .actors
+            .vault
+            .ask(Bootstrap {
+                seal_key_raw: seal_key_buffer,
+            })
+            .await
+        {
+            Ok(()) => {
+                info!("Successfully bootstrapped vault with client-provided key");
+                Ok(())
+            }
+            Err(SendError::HandlerError(vault::Error::AlreadyBootstrapped)) => {
+                Err(Error::AlreadyBootstrapped)
+            }
+            Err(SendError::HandlerError(err)) => {
+                error!(?err, "Vault failed to bootstrap vault");
+                Err(Error::InvalidKey)
+            }
+            Err(err) => {
+                error!(?err, "Failed to send bootstrap request to vault");
+                Err(Error::internal("Vault error"))
+            }
+        }
+    }
+
+    #[message]
+    pub async fn handle_vault_state(&mut self) -> Result<VaultState, Error> {
+        let answer = self
+            .actors
+            .vault
+            .ask(GetState {})
+            .await
+            .map_err(|_| Error::internal("failed to query vault"))?;
+
+        Ok(answer)
+    }
+}
+
+impl Message<events::Bootstrapped> for VaultGate {
+    type Reply = ();
+
+    async fn handle(
+        &mut self,
+        _: events::Bootstrapped,
+        ctx: &mut kameo::prelude::Context<Self, Self::Reply>,
+    ) -> Self::Reply {
+        let result = async {
+            let mut conn = self
+                .db
+                .get()
+                .await
+                .map_err(|_| Error::internal("DB unavailable"))?;
+            integrity::sign_entity(
+                &mut conn,
+                &self.actors.vault,
+                &self.auth_creds,
+                self.auth_creds.id,
+            )
+            .await
+            .map_err(|e| {
+                error!(?e, "Failed to sign integrity envelope on bootstrap");
+                Error::internal("Integrity sign failed")
+            })?;
+            Ok(())
+        }
+        .await;
+
+        if let Some(tx) = self.promotion_tx.take() {
+            let _ = tx.send(result);
+        }
+        ctx.stop();
+    }
+}
+
+impl Message<events::Unsealed> for VaultGate {
+    type Reply = ();
+
+    async fn handle(
+        &mut self,
+        _: events::Unsealed,
+        ctx: &mut kameo::prelude::Context<Self, Self::Reply>,
+    ) -> Self::Reply {
+        if let Some(tx) = self.promotion_tx.take() {
+            let _ = tx.send(Ok(()));
+        }
+        ctx.stop();
+    }
+}

server/crates/arbiter-server/src/peers/user_agent/vault_gate/state.rs

@@ -0,0 +1,11 @@
+use x25519_dalek::{PublicKey, SharedSecret};
+
+#[derive(Default)]
+pub enum State {
+    #[default]
+    Idle,
+    ReadyForExchange {
+        server_key: PublicKey,
+        secret: SharedSecret,
+    },
+}

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

@@ -1,23 +1,22 @@
+use super::common::ChannelTransport;
 use arbiter_crypto::{
-    authn::{self, CLIENT_CONTEXT, format_challenge},
+    authn::{self, AuthChallenge, CLIENT_CONTEXT},
     safecell::{SafeCell, SafeCellHandle as _},
 };
-use arbiter_proto::ClientMetadata;
-use arbiter_proto::transport::{Receiver, Sender};
+use arbiter_proto::{
+    ClientMetadata,
+    transport::{Receiver, Sender},
+};
 use arbiter_server::{
-    actors::{
-        GlobalActors,
-        client::{ClientConnection, ClientCredentials, auth, connect_client},
-        keyholder::Bootstrap,
-    },
+    actors::{GlobalActors, vault::Bootstrap},
     crypto::integrity,
     db::{self, schema},
+    peers::client::{ClientConnection, ClientCredentials, auth, connect_client},
 };
+
 use diesel::{ExpressionMethods as _, NullableExpressionMethods as _, QueryDsl as _, insert_into};
 use diesel_async::RunQueryDsl;
-use ml_dsa::{KeyGen, MlDsa87, SigningKey, VerifyingKey, signature::Keypair as _};
-
-use super::common::ChannelTransport;
+use ml_dsa::{KeyGen, MlDsa87, SigningKey, VerifyingKey, signature::Keypair};
 
 fn metadata(name: &str, description: Option<&str>, version: Option<&str>) -> ClientMetadata {
     ClientMetadata {
@@ -27,6 +26,10 @@ fn metadata(name: &str, description: Option<&str>, version: Option<&str>) -> Cli
     }
 }
 
+fn verifying_key(key: &SigningKey<MlDsa87>) -> VerifyingKey<MlDsa87> {
+    <SigningKey<MlDsa87> as Keypair>::verifying_key(key)
+}
+
 async fn insert_registered_client(
     db: &db::DatabasePool,
     actors: &GlobalActors,
@@ -48,7 +51,7 @@ async fn insert_registered_client(
         .unwrap();
     let client_id: i32 = insert_into(program_client::table)
         .values((
-            program_client::public_key.eq(pubkey.encode().to_vec()),
+            program_client::public_key.eq(pubkey.encode().0.to_vec()),
             program_client::metadata_id.eq(metadata_id),
         ))
         .returning(program_client::id)
@@ -58,10 +61,9 @@ async fn insert_registered_client(
 
     integrity::sign_entity(
         &mut conn,
-        &actors.key_holder,
+        &actors.vault,
         &ClientCredentials {
             pubkey: pubkey.into(),
-            nonce: 1,
         },
         client_id,
     )
@@ -69,12 +71,8 @@ async fn insert_registered_client(
     .unwrap();
 }
 
-fn sign_client_challenge(
-    key: &SigningKey<MlDsa87>,
-    nonce: i32,
-    pubkey: &authn::PublicKey,
-) -> authn::Signature {
-    let challenge = format_challenge(nonce, &pubkey.to_bytes());
+fn sign_client_challenge(key: &SigningKey<MlDsa87>, challenge: &AuthChallenge) -> authn::Signature {
+    let challenge = challenge.format();
     key.signing_key()
         .sign_deterministic(&challenge, CLIENT_CONTEXT)
         .unwrap()
@@ -83,16 +81,13 @@ fn sign_client_challenge(
 
 async fn insert_bootstrap_sentinel_useragent(db: &db::DatabasePool) {
     let mut conn = db.get().await.unwrap();
-    let sentinel_key = MlDsa87::key_gen(&mut rand::rng())
-        .verifying_key()
+    let sentinel_key = verifying_key(&MlDsa87::key_gen(&mut rand::rng()))
         .encode()
+        .0
         .to_vec();
 
     insert_into(schema::useragent_client::table)
-        .values((
-            schema::useragent_client::public_key.eq(sentinel_key),
-            schema::useragent_client::key_type.eq(1i32),
-        ))
+        .values((schema::useragent_client::public_key.eq(sentinel_key),))
         .execute(&mut conn)
         .await
         .unwrap();
@@ -103,7 +98,7 @@ async fn spawn_test_actors(db: &db::DatabasePool) -> GlobalActors {
 
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
     actors
-        .key_holder
+        .vault
         .ask(Bootstrap {
             seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
         })
@@ -114,7 +109,7 @@ async fn spawn_test_actors(db: &db::DatabasePool) -> GlobalActors {
 
 #[tokio::test]
 #[test_log::test]
-pub async fn test_unregistered_pubkey_rejected() {
+pub async fn unregistered_pubkey_rejected() {
     let db = db::create_test_pool().await;
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
@@ -129,7 +124,7 @@ pub async fn test_unregistered_pubkey_rejected() {
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key().into(),
+            pubkey: verifying_key(&new_key).into(),
             metadata: metadata("client", Some("desc"), Some("1.0.0")),
         })
         .await
@@ -141,18 +136,18 @@ pub async fn test_unregistered_pubkey_rejected() {
 
 #[tokio::test]
 #[test_log::test]
-pub async fn test_challenge_auth() {
+pub async fn challenge_auth() {
     let db = db::create_test_pool().await;
     let actors = spawn_test_actors(&db).await;
 
     let new_key = MlDsa87::key_gen(&mut rand::rng());
 
-    insert_registered_client(
+    Box::pin(insert_registered_client(
         &db,
         &actors,
-        new_key.verifying_key(),
+        verifying_key(&new_key),
         &metadata("client", Some("desc"), Some("1.0.0")),
-    )
+    ))
     .await;
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
@@ -165,7 +160,7 @@ pub async fn test_challenge_auth() {
     // Send challenge request
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key().into(),
+            pubkey: verifying_key(&new_key).into(),
             metadata: metadata("client", Some("desc"), Some("1.0.0")),
         })
         .await
@@ -178,14 +173,14 @@ pub async fn test_challenge_auth() {
         .expect("should receive challenge");
     let challenge = match response {
         Ok(resp) => match resp {
-            auth::Outbound::AuthChallenge { pubkey, nonce } => (pubkey, nonce),
-            other => panic!("Expected AuthChallenge, got {other:?}"),
+            auth::Outbound::AuthChallenge { challenge } => challenge,
+            other @ auth::Outbound::AuthSuccess => panic!("Expected AuthChallenge, got {other:?}"),
         },
         Err(err) => panic!("Expected Ok response, got Err({err:?})"),
     };
 
     // Sign the challenge and send solution
-    let signature = sign_client_challenge(&new_key, challenge.1, &challenge.0);
+    let signature = sign_client_challenge(&new_key, &challenge);
 
     test_transport
         .send(auth::Inbound::AuthChallengeSolution { signature })
@@ -208,13 +203,19 @@ pub async fn test_challenge_auth() {
 
 #[tokio::test]
 #[test_log::test]
-pub async fn test_metadata_unchanged_does_not_append_history() {
+pub async fn metadata_unchanged_does_not_append_history() {
     let db = db::create_test_pool().await;
     let actors = spawn_test_actors(&db).await;
     let new_key = MlDsa87::key_gen(&mut rand::rng());
     let requested = metadata("client", Some("desc"), Some("1.0.0"));
 
-    insert_registered_client(&db, &actors, new_key.verifying_key(), &requested).await;
+    Box::pin(insert_registered_client(
+        &db,
+        &actors,
+        verifying_key(&new_key),
+        &requested,
+    ))
+    .await;
 
     let props = ClientConnection::new(db.clone(), actors);
 
@@ -226,18 +227,18 @@ pub async fn test_metadata_unchanged_does_not_append_history() {
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key().into(),
+            pubkey: verifying_key(&new_key).into(),
             metadata: requested,
         })
         .await
         .unwrap();
 
     let response = test_transport.recv().await.unwrap().unwrap();
-    let (pubkey, nonce) = match response {
-        auth::Outbound::AuthChallenge { pubkey, nonce } => (pubkey, nonce),
-        other => panic!("Expected AuthChallenge, got {other:?}"),
+    let challenge = match response {
+        auth::Outbound::AuthChallenge { challenge } => challenge,
+        auth::Outbound::AuthSuccess => panic!("Expected AuthChallenge, got AuthSuccess"),
     };
-    let signature = sign_client_challenge(&new_key, nonce, &pubkey);
+    let signature = sign_client_challenge(&new_key, &challenge);
     test_transport
         .send(auth::Inbound::AuthChallengeSolution { signature })
         .await
@@ -265,17 +266,17 @@ pub async fn test_metadata_unchanged_does_not_append_history() {
 
 #[tokio::test]
 #[test_log::test]
-pub async fn test_metadata_change_appends_history_and_repoints_binding() {
+pub async fn metadata_change_appends_history_and_repoints_binding() {
     let db = db::create_test_pool().await;
     let actors = spawn_test_actors(&db).await;
     let new_key = MlDsa87::key_gen(&mut rand::rng());
 
-    insert_registered_client(
+    Box::pin(insert_registered_client(
         &db,
         &actors,
-        new_key.verifying_key(),
+        verifying_key(&new_key),
         &metadata("client", Some("old"), Some("1.0.0")),
-    )
+    ))
     .await;
 
     let props = ClientConnection::new(db.clone(), actors);
@@ -288,23 +289,23 @@ pub async fn test_metadata_change_appends_history_and_repoints_binding() {
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key().into(),
+            pubkey: verifying_key(&new_key).into(),
             metadata: metadata("client", Some("new"), Some("2.0.0")),
         })
         .await
         .unwrap();
 
     let response = test_transport.recv().await.unwrap().unwrap();
-    let (pubkey, nonce) = match response {
-        auth::Outbound::AuthChallenge { pubkey, nonce } => (pubkey, nonce),
-        other => panic!("Expected AuthChallenge, got {other:?}"),
+    let challenge = match response {
+        auth::Outbound::AuthChallenge { challenge } => challenge,
+        auth::Outbound::AuthSuccess => panic!("Expected AuthChallenge, got AuthSuccess"),
     };
-    let signature = sign_client_challenge(&new_key, nonce, &pubkey);
+    let signature = sign_client_challenge(&new_key, &challenge);
     test_transport
         .send(auth::Inbound::AuthChallengeSolution { signature })
         .await
         .unwrap();
-    let _ = test_transport.recv().await.unwrap();
+    drop(test_transport.recv().await.unwrap());
     task.await.unwrap();
 
     {
@@ -352,7 +353,7 @@ pub async fn test_metadata_change_appends_history_and_repoints_binding() {
 
 #[tokio::test]
 #[test_log::test]
-pub async fn test_challenge_auth_rejects_integrity_tag_mismatch() {
+pub async fn challenge_auth_rejects_integrity_tag_mismatch() {
     let db = db::create_test_pool().await;
     let actors = spawn_test_actors(&db).await;
 
@@ -374,7 +375,7 @@ pub async fn test_challenge_auth_rejects_integrity_tag_mismatch() {
             .unwrap();
         insert_into(program_client::table)
             .values((
-                program_client::public_key.eq(new_key.verifying_key().encode().to_vec()),
+                program_client::public_key.eq(verifying_key(&new_key).encode().0.to_vec()),
                 program_client::metadata_id.eq(metadata_id),
             ))
             .execute(&mut conn)
@@ -391,7 +392,7 @@ pub async fn test_challenge_auth_rejects_integrity_tag_mismatch() {
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key().into(),
+            pubkey: verifying_key(&new_key).into(),
             metadata: requested,
         })
         .await

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

@@ -1,7 +1,11 @@
+#![allow(
+    dead_code,
+    reason = "Common test utilities that may not be used in every test"
+)]
 use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_proto::transport::{Bi, Error, Receiver, Sender};
 use arbiter_server::{
-    actors::keyholder::KeyHolder,
+    actors::{GlobalActors, vault::Vault},
     db::{self, schema},
 };
 
@@ -10,9 +14,10 @@ use diesel::QueryDsl;
 use diesel_async::RunQueryDsl;
 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();
+pub(crate) async fn bootstrapped_vault(db: &db::DatabasePool) -> Vault {
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
     actor
         .bootstrap(SafeCell::new(b"test-seal-key".to_vec()))
         .await
@@ -20,8 +25,7 @@ pub async fn bootstrapped_keyholder(db: &db::DatabasePool) -> KeyHolder {
     actor
 }
 
-#[allow(dead_code)]
-pub async fn root_key_history_id(db: &db::DatabasePool) -> i32 {
+pub(crate) async fn root_key_history_id(db: &db::DatabasePool) -> i32 {
     let mut conn = db.get().await.unwrap();
     let id = schema::arbiter_settings::table
         .select(schema::arbiter_settings::root_key_id)
@@ -31,15 +35,13 @@ pub async fn root_key_history_id(db: &db::DatabasePool) -> i32 {
     id.expect("root_key_id should be set after bootstrap")
 }
 
-#[allow(dead_code)]
-pub struct ChannelTransport<T, Y> {
+pub(crate) struct ChannelTransport<T, Y> {
     receiver: mpsc::Receiver<T>,
     sender: mpsc::Sender<Y>,
 }
 
 impl<T, Y> ChannelTransport<T, Y> {
-    #[allow(dead_code)]
-    pub fn new() -> (Self, ChannelTransport<Y, T>) {
+    pub(crate) fn new() -> (Self, ChannelTransport<Y, T>) {
         let (tx1, rx1) = mpsc::channel(10);
         let (tx2, rx2) = mpsc::channel(10);
         (

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

@@ -1,8 +0,0 @@
-mod common;
-
-#[path = "keyholder/concurrency.rs"]
-mod concurrency;
-#[path = "keyholder/lifecycle.rs"]
-mod lifecycle;
-#[path = "keyholder/storage.rs"]
-mod storage;

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

@@ -1,44 +1,161 @@
+use super::common::ChannelTransport;
 use arbiter_crypto::{
-    authn::{self, USERAGENT_CONTEXT, format_challenge},
+    authn::{self, AuthChallenge, USERAGENT_CONTEXT},
     safecell::{SafeCell, SafeCellHandle as _},
 };
-
-use arbiter_proto::transport::{Receiver, Sender};
+use arbiter_proto::transport::{Error as TransportError, Receiver, Sender};
 use arbiter_server::{
-    actors::{
-        GlobalActors,
-        bootstrap::GetToken,
-        keyholder::Bootstrap,
-        user_agent::{UserAgentConnection, UserAgentCredentials, auth},
-    },
+    actors::{GlobalActors, bootstrap::GetToken, vault::Bootstrap},
     crypto::integrity,
     db::{self, schema},
+    peers::user_agent::{self, Credentials, UserAgentConnection, auth, vault_gate},
 };
+
+use async_trait::async_trait;
 use diesel::{ExpressionMethods as _, QueryDsl, insert_into};
 use diesel_async::RunQueryDsl;
-use ml_dsa::{KeyGen, MlDsa87, SigningKey, signature::Keypair as _};
+use ml_dsa::{KeyGen, MlDsa87, SigningKey, VerifyingKey, signature::Keypair};
+use tokio::sync::mpsc;
 
-use super::common::ChannelTransport;
+fn verifying_key(key: &SigningKey<MlDsa87>) -> VerifyingKey<MlDsa87> {
+    <SigningKey<MlDsa87> as Keypair>::verifying_key(key)
+}
 
 fn sign_useragent_challenge(
     key: &SigningKey<MlDsa87>,
-    nonce: i32,
-    pubkey_bytes: &[u8],
+    challenge: &AuthChallenge,
 ) -> authn::Signature {
-    let challenge = format_challenge(nonce, pubkey_bytes);
+    let challenge = challenge.format();
     key.signing_key()
         .sign_deterministic(&challenge, USERAGENT_CONTEXT)
         .unwrap()
         .into()
 }
 
+fn tamper_challenge(challenge: &AuthChallenge) -> AuthChallenge {
+    let mut challenge = challenge.clone();
+    challenge.nonce[0] ^= 1;
+    challenge
+}
+
+struct NullOobSender;
+
+#[async_trait]
+impl Sender<user_agent::OutOfBand> for NullOobSender {
+    async fn send(&mut self, _item: user_agent::OutOfBand) -> Result<(), TransportError> {
+        Ok(())
+    }
+}
+
+struct StartServerTransport {
+    auth_rx: mpsc::Receiver<auth::Inbound>,
+    auth_tx: mpsc::Sender<Result<auth::Outbound, auth::Error>>,
+    vault_rx: mpsc::Receiver<vault_gate::Inbound>,
+    vault_tx: mpsc::Sender<Result<vault_gate::Outbound, vault_gate::Error>>,
+}
+
+struct StartTestTransport {
+    auth_rx: mpsc::Receiver<Result<auth::Outbound, auth::Error>>,
+    auth_tx: mpsc::Sender<auth::Inbound>,
+}
+
+fn start_transport_pair() -> (StartServerTransport, StartTestTransport) {
+    let (auth_in_tx, auth_in_rx) = mpsc::channel(10);
+    let (auth_out_tx, auth_out_rx) = mpsc::channel(10);
+    let (_vault_in_tx, vault_in_rx) = mpsc::channel(10);
+    let (vault_out_tx, _vault_out_rx) = mpsc::channel(10);
+
+    (
+        StartServerTransport {
+            auth_rx: auth_in_rx,
+            auth_tx: auth_out_tx,
+            vault_rx: vault_in_rx,
+            vault_tx: vault_out_tx,
+        },
+        StartTestTransport {
+            auth_rx: auth_out_rx,
+            auth_tx: auth_in_tx,
+        },
+    )
+}
+
+#[async_trait]
+impl Receiver<auth::Inbound> for StartServerTransport {
+    async fn recv(&mut self) -> Option<auth::Inbound> {
+        self.auth_rx.recv().await
+    }
+}
+
+#[async_trait]
+impl Sender<Result<auth::Outbound, auth::Error>> for StartServerTransport {
+    async fn send(
+        &mut self,
+        item: Result<auth::Outbound, auth::Error>,
+    ) -> Result<(), TransportError> {
+        self.auth_tx
+            .send(item)
+            .await
+            .map_err(|_| TransportError::ChannelClosed)
+    }
+}
+
+impl arbiter_proto::transport::Bi<auth::Inbound, Result<auth::Outbound, auth::Error>>
+    for StartServerTransport
+{
+}
+
+#[async_trait]
+impl Receiver<vault_gate::Inbound> for StartServerTransport {
+    async fn recv(&mut self) -> Option<vault_gate::Inbound> {
+        self.vault_rx.recv().await
+    }
+}
+
+#[async_trait]
+impl Sender<Result<vault_gate::Outbound, vault_gate::Error>> for StartServerTransport {
+    async fn send(
+        &mut self,
+        item: Result<vault_gate::Outbound, vault_gate::Error>,
+    ) -> Result<(), TransportError> {
+        self.vault_tx
+            .send(item)
+            .await
+            .map_err(|_| TransportError::ChannelClosed)
+    }
+}
+
+impl
+    arbiter_proto::transport::Bi<
+        vault_gate::Inbound,
+        Result<vault_gate::Outbound, vault_gate::Error>,
+    > for StartServerTransport
+{
+}
+
+#[async_trait]
+impl Receiver<Result<auth::Outbound, auth::Error>> for StartTestTransport {
+    async fn recv(&mut self) -> Option<Result<auth::Outbound, auth::Error>> {
+        self.auth_rx.recv().await
+    }
+}
+
+#[async_trait]
+impl Sender<auth::Inbound> for StartTestTransport {
+    async fn send(&mut self, item: auth::Inbound) -> Result<(), TransportError> {
+        self.auth_tx
+            .send(item)
+            .await
+            .map_err(|_| TransportError::ChannelClosed)
+    }
+}
+
 #[tokio::test]
 #[test_log::test]
-pub async fn test_bootstrap_token_auth() {
+pub async fn bootstrap_token_auth() {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
     actors
-        .key_holder
+        .vault
         .ask(Bootstrap {
             seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
         })
@@ -46,30 +163,45 @@ pub async fn test_bootstrap_token_auth() {
         .unwrap();
     let token = actors.bootstrapper.ask(GetToken).await.unwrap().unwrap();
 
-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
     let db_for_task = db.clone();
     let task = tokio::spawn(async move {
         let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        auth::authenticate(&mut props, &mut server_transport).await
     });
 
     let new_key = MlDsa87::key_gen(&mut rand::rng());
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key().into(),
+            pubkey: verifying_key(&new_key).into(),
             bootstrap_token: Some(token),
         })
         .await
         .unwrap();
 
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive challenge");
+    let challenge = match response {
+        Ok(auth::Outbound::AuthChallenge { challenge }) => challenge,
+        other => panic!("Expected AuthChallenge, got {other:?}"),
+    };
+
+    let signature = sign_useragent_challenge(&new_key, &challenge);
+
+    test_transport
+        .send(auth::Inbound::AuthChallengeSolution {
+            signature: signature.to_bytes(),
+        })
+        .await
+        .unwrap();
+
     let response = test_transport
         .recv()
         .await
         .expect("should receive auth result");
-    match response {
-        Ok(auth::Outbound::AuthSuccess) => {}
-        other => panic!("Expected AuthSuccess, got {other:?}"),
-    }
+    assert!(matches!(response, Ok(auth::Outbound::AuthSuccess)));
 
     task.await.unwrap().unwrap();
 
@@ -79,27 +211,44 @@ pub async fn test_bootstrap_token_auth() {
         .first::<Vec<u8>>(&mut conn)
         .await
         .unwrap();
-    assert_eq!(stored_pubkey, new_key.verifying_key().encode().to_vec());
+    assert_eq!(stored_pubkey, verifying_key(&new_key).encode().0.to_vec());
 }
 
 #[tokio::test]
 #[test_log::test]
-pub async fn test_bootstrap_invalid_token_auth() {
+pub async fn bootstrap_invalid_token_auth() {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
 
-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
     let db_for_task = db.clone();
     let task = tokio::spawn(async move {
         let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        auth::authenticate(&mut props, &mut server_transport).await
     });
 
     let new_key = MlDsa87::key_gen(&mut rand::rng());
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key().into(),
-            bootstrap_token: Some("invalid_token".to_string()),
+            pubkey: verifying_key(&new_key).into(),
+            bootstrap_token: Some("invalid_token".to_owned()),
+        })
+        .await
+        .unwrap();
+
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive challenge");
+    let challenge = match response {
+        Ok(auth::Outbound::AuthChallenge { challenge }) => challenge,
+        other => panic!("Expected AuthChallenge, got {other:?}"),
+    };
+
+    let signature = sign_useragent_challenge(&new_key, &challenge);
+    test_transport
+        .send(auth::Inbound::AuthChallengeSolution {
+            signature: signature.to_bytes(),
         })
         .await
         .unwrap();
@@ -120,11 +269,11 @@ pub async fn test_bootstrap_invalid_token_auth() {
 
 #[tokio::test]
 #[test_log::test]
-pub async fn test_challenge_auth() {
+pub async fn challenge_auth() {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
     actors
-        .key_holder
+        .vault
         .ask(Bootstrap {
             seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
         })
@@ -132,25 +281,22 @@ pub async fn test_challenge_auth() {
         .unwrap();
 
     let new_key = MlDsa87::key_gen(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().encode().to_vec();
+    let pubkey_bytes = authn::PublicKey::from(verifying_key(&new_key)).to_bytes();
 
     {
         let mut conn = db.get().await.unwrap();
         let id: i32 = insert_into(schema::useragent_client::table)
-            .values((
-                schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
-                schema::useragent_client::key_type.eq(1i32),
-            ))
+            .values((schema::useragent_client::public_key.eq(pubkey_bytes.clone()),))
             .returning(schema::useragent_client::id)
             .get_result(&mut conn)
             .await
             .unwrap();
         integrity::sign_entity(
             &mut conn,
-            &actors.key_holder,
-            &UserAgentCredentials {
-                pubkey: new_key.verifying_key().into(),
-                nonce: 1,
+            &actors.vault,
+            &Credentials {
+                id,
+                pubkey: verifying_key(&new_key).into(),
             },
             id,
         )
@@ -158,16 +304,16 @@ pub async fn test_challenge_auth() {
         .unwrap();
     }
 
-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
     let db_for_task = db.clone();
     let task = tokio::spawn(async move {
         let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        auth::authenticate(&mut props, &mut server_transport).await
     });
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key().into(),
+            pubkey: verifying_key(&new_key).into(),
             bootstrap_token: None,
         })
         .await
@@ -179,13 +325,13 @@ pub async fn test_challenge_auth() {
         .expect("should receive challenge");
     let challenge = match response {
         Ok(resp) => match resp {
-            auth::Outbound::AuthChallenge { nonce } => nonce,
-            other => panic!("Expected AuthChallenge, got {other:?}"),
+            auth::Outbound::AuthChallenge { challenge } => challenge,
+            auth::Outbound::AuthSuccess => panic!("Expected AuthChallenge, got AuthSuccess"),
         },
         Err(err) => panic!("Expected Ok response, got Err({err:?})"),
     };
 
-    let signature = sign_useragent_challenge(&new_key, challenge, &pubkey_bytes);
+    let signature = sign_useragent_challenge(&new_key, &challenge);
 
     test_transport
         .send(auth::Inbound::AuthChallengeSolution {
@@ -208,12 +354,12 @@ pub async fn test_challenge_auth() {
 
 #[tokio::test]
 #[test_log::test]
-pub async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed() {
+pub async fn challenge_auth_rejects_integrity_tag_mismatch_when_unsealed() {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
 
     actors
-        .key_holder
+        .vault
         .ask(Bootstrap {
             seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
         })
@@ -221,91 +367,27 @@ pub async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed()
         .unwrap();
 
     let new_key = MlDsa87::key_gen(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().encode().to_vec();
+    let pubkey_bytes = authn::PublicKey::from(verifying_key(&new_key)).to_bytes();
 
     {
         let mut conn = db.get().await.unwrap();
         insert_into(schema::useragent_client::table)
-            .values((
-                schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
-                schema::useragent_client::key_type.eq(1i32),
-            ))
+            .values((schema::useragent_client::public_key.eq(pubkey_bytes.clone()),))
             .execute(&mut conn)
             .await
             .unwrap();
     }
 
-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (server_transport, mut test_transport) = start_transport_pair();
     let db_for_task = db.clone();
     let task = tokio::spawn(async move {
         let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        user_agent::start(&mut props, server_transport, Box::new(NullOobSender)).await
     });
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key().into(),
-            bootstrap_token: None,
-        })
-        .await
-        .unwrap();
-
-    assert!(matches!(
-        task.await.unwrap(),
-        Err(auth::Error::Internal { .. })
-    ));
-}
-
-#[tokio::test]
-#[test_log::test]
-pub async fn test_challenge_auth_rejects_invalid_signature() {
-    let db = db::create_test_pool().await;
-    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
-    actors
-        .key_holder
-        .ask(Bootstrap {
-            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
-        })
-        .await
-        .unwrap();
-
-    let new_key = MlDsa87::key_gen(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().encode().to_vec();
-
-    {
-        let mut conn = db.get().await.unwrap();
-        let id: i32 = insert_into(schema::useragent_client::table)
-            .values((
-                schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
-                schema::useragent_client::key_type.eq(1i32),
-            ))
-            .returning(schema::useragent_client::id)
-            .get_result(&mut conn)
-            .await
-            .unwrap();
-        integrity::sign_entity(
-            &mut conn,
-            &actors.key_holder,
-            &UserAgentCredentials {
-                pubkey: new_key.verifying_key().into(),
-                nonce: 1,
-            },
-            id,
-        )
-        .await
-        .unwrap();
-    }
-
-    let (server_transport, mut test_transport) = ChannelTransport::new();
-    let db_for_task = db.clone();
-    let task = tokio::spawn(async move {
-        let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
-    });
-
-    test_transport
-        .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key().into(),
+            pubkey: verifying_key(&new_key).into(),
             bootstrap_token: None,
         })
         .await
@@ -317,13 +399,98 @@ pub async fn test_challenge_auth_rejects_invalid_signature() {
         .expect("should receive challenge");
     let challenge = match response {
         Ok(resp) => match resp {
-            auth::Outbound::AuthChallenge { nonce } => nonce,
+            auth::Outbound::AuthChallenge { challenge } => challenge,
             other => panic!("Expected AuthChallenge, got {other:?}"),
         },
         Err(err) => panic!("Expected Ok response, got Err({err:?})"),
     };
 
-    let signature = sign_useragent_challenge(&new_key, challenge + 1, &pubkey_bytes);
+    let signature = sign_useragent_challenge(&new_key, &challenge);
+
+    test_transport
+        .send(auth::Inbound::AuthChallengeSolution {
+            signature: signature.to_bytes(),
+        })
+        .await
+        .unwrap();
+
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive auth result");
+    assert!(matches!(response, Ok(auth::Outbound::AuthSuccess)));
+
+    assert!(matches!(
+        task.await.unwrap(),
+        Err(user_agent::Error::Internal(_))
+    ));
+}
+
+#[tokio::test]
+#[test_log::test]
+pub async fn challenge_auth_rejects_invalid_signature() {
+    let db = db::create_test_pool().await;
+    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+    actors
+        .vault
+        .ask(Bootstrap {
+            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
+        })
+        .await
+        .unwrap();
+
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
+    let pubkey_bytes = authn::PublicKey::from(verifying_key(&new_key)).to_bytes();
+
+    {
+        let mut conn = db.get().await.unwrap();
+        let id: i32 = insert_into(schema::useragent_client::table)
+            .values((schema::useragent_client::public_key.eq(pubkey_bytes.clone()),))
+            .returning(schema::useragent_client::id)
+            .get_result(&mut conn)
+            .await
+            .unwrap();
+        integrity::sign_entity(
+            &mut conn,
+            &actors.vault,
+            &Credentials {
+                id,
+                pubkey: verifying_key(&new_key).into(),
+            },
+            id,
+        )
+        .await
+        .unwrap();
+    }
+
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
+    let db_for_task = db.clone();
+    let task = tokio::spawn(async move {
+        let mut props = UserAgentConnection::new(db_for_task, actors);
+        auth::authenticate(&mut props, &mut server_transport).await
+    });
+
+    test_transport
+        .send(auth::Inbound::AuthChallengeRequest {
+            pubkey: verifying_key(&new_key).into(),
+            bootstrap_token: None,
+        })
+        .await
+        .unwrap();
+
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive challenge");
+    let challenge = match response {
+        Ok(resp) => match resp {
+            auth::Outbound::AuthChallenge { challenge } => challenge,
+            auth::Outbound::AuthSuccess => panic!("Expected AuthChallenge, got AuthSuccess"),
+        },
+        Err(err) => panic!("Expected Ok response, got Err({err:?})"),
+    };
+
+    let signature = sign_useragent_challenge(&new_key, &tamper_challenge(&challenge));
 
     test_transport
         .send(auth::Inbound::AuthChallengeSolution {

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

@@ -1,49 +1,62 @@
-use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use arbiter_crypto::{
+    authn,
+    safecell::{SafeCell, SafeCellHandle as _},
+};
 use arbiter_server::{
     actors::{
         GlobalActors,
-        keyholder::{Bootstrap, Seal},
-        user_agent::{
-            UserAgentSession,
-            session::connection::{HandleUnsealEncryptedKey, HandleUnsealRequest, UnsealError},
-        },
+        vault::{Bootstrap, Seal},
     },
     db,
+    peers::user_agent::{
+        Credentials,
+        vault_gate::{
+            Error as VaultGateError, HandleHandshake, HandleUnsealEncryptedKey, VaultGate,
+        },
+    },
 };
 
 use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
 use kameo::actor::Spawn as _;
+use tokio::sync::oneshot;
 use x25519_dalek::{EphemeralSecret, PublicKey};
 
-async fn setup_sealed_user_agent(
+async fn setup_sealed_gate(
     seal_key: &[u8],
-) -> (db::DatabasePool, kameo::actor::ActorRef<UserAgentSession>) {
+) -> (
+    db::DatabasePool,
+    kameo::actor::ActorRef<VaultGate>,
+    oneshot::Receiver<Result<(), VaultGateError>>,
+) {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
 
     actors
-        .key_holder
+        .vault
         .ask(Bootstrap {
             seal_key_raw: SafeCell::new(seal_key.to_vec()),
         })
         .await
         .unwrap();
-    actors.key_holder.ask(Seal).await.unwrap();
+    actors.vault.ask(Seal).await.unwrap();
 
-    let session = UserAgentSession::spawn(UserAgentSession::new_test(db.clone(), actors));
+    let (promotion_tx, promotion_rx) = oneshot::channel();
+    let pubkey = authn::SigningKey::generate().public_key();
+    let auth_creds = Credentials { id: 1, pubkey };
+    let gate = VaultGate::spawn(VaultGate::new(auth_creds, actors, db.clone(), promotion_tx));
 
-    (db, session)
+    (db, gate, promotion_rx)
 }
 
 async fn client_dh_encrypt(
-    user_agent: &kameo::actor::ActorRef<UserAgentSession>,
+    gate: &kameo::actor::ActorRef<VaultGate>,
     key_to_send: &[u8],
 ) -> HandleUnsealEncryptedKey {
     let client_secret = EphemeralSecret::random();
     let client_public = PublicKey::from(&client_secret);
 
-    let response = user_agent
-        .ask(HandleUnsealRequest {
+    let response = gate
+        .ask(HandleHandshake {
             client_pubkey: client_public,
         })
         .await
@@ -69,48 +82,49 @@ async fn client_dh_encrypt(
 
 #[tokio::test]
 #[test_log::test]
-pub async fn test_unseal_success() {
+pub async fn unseal_success() {
     let seal_key = b"test-seal-key";
-    let (_db, user_agent) = setup_sealed_user_agent(seal_key).await;
+    let (_db, gate, _promotion_rx) = setup_sealed_gate(seal_key).await;
 
-    let encrypted_key = client_dh_encrypt(&user_agent, seal_key).await;
+    let encrypted_key = client_dh_encrypt(&gate, seal_key).await;
 
-    let response = user_agent.ask(encrypted_key).await;
+    let response = gate.ask(encrypted_key).await;
     assert!(matches!(response, Ok(())));
 }
 
 #[tokio::test]
 #[test_log::test]
-pub async fn test_unseal_wrong_seal_key() {
-    let (_db, user_agent) = setup_sealed_user_agent(b"correct-key").await;
+pub async fn unseal_wrong_seal_key() {
+    let seal_key = b"test-seal-key";
+    let (_db, gate, _promotion_rx) = setup_sealed_gate(seal_key).await;
 
-    let encrypted_key = client_dh_encrypt(&user_agent, b"wrong-key").await;
+    let encrypted_key = client_dh_encrypt(&gate, b"wrong-key").await;
 
-    let response = user_agent.ask(encrypted_key).await;
+    let response = gate.ask(encrypted_key).await;
     assert!(matches!(
         response,
         Err(kameo::error::SendError::HandlerError(
-            UnsealError::InvalidKey
+            VaultGateError::InvalidKey
         ))
     ));
 }
 
 #[tokio::test]
 #[test_log::test]
-pub async fn test_unseal_corrupted_ciphertext() {
-    let (_db, user_agent) = setup_sealed_user_agent(b"test-key").await;
+pub async fn unseal_corrupted_ciphertext() {
+    let seal_key = b"test-seal-key";
+    let (_db, gate, _promotion_rx) = setup_sealed_gate(seal_key).await;
 
     let client_secret = EphemeralSecret::random();
     let client_public = PublicKey::from(&client_secret);
 
-    user_agent
-        .ask(HandleUnsealRequest {
+    gate.ask(HandleHandshake {
         client_pubkey: client_public,
     })
     .await
     .unwrap();
 
-    let response = user_agent
+    let response = gate
         .ask(HandleUnsealEncryptedKey {
             nonce: vec![0u8; 24],
             ciphertext: vec![0u8; 32],
@@ -121,33 +135,33 @@ pub async fn test_unseal_corrupted_ciphertext() {
     assert!(matches!(
         response,
         Err(kameo::error::SendError::HandlerError(
-            UnsealError::InvalidKey
+            VaultGateError::InvalidKey
         ))
     ));
 }
 
 #[tokio::test]
 #[test_log::test]
-pub async fn test_unseal_retry_after_invalid_key() {
+pub async fn unseal_retry_after_invalid_key() {
     let seal_key = b"real-seal-key";
-    let (_db, user_agent) = setup_sealed_user_agent(seal_key).await;
+    let (_db, gate, _promotion_rx) = setup_sealed_gate(seal_key).await;
 
     {
-        let encrypted_key = client_dh_encrypt(&user_agent, b"wrong-key").await;
+        let encrypted_key = client_dh_encrypt(&gate, b"wrong-key").await;
 
-        let response = user_agent.ask(encrypted_key).await;
+        let response = gate.ask(encrypted_key).await;
         assert!(matches!(
             response,
             Err(kameo::error::SendError::HandlerError(
-                UnsealError::InvalidKey
+                VaultGateError::InvalidKey
             ))
         ));
     }
 
     {
-        let encrypted_key = client_dh_encrypt(&user_agent, seal_key).await;
+        let encrypted_key = client_dh_encrypt(&gate, seal_key).await;
 
-        let response = user_agent.ask(encrypted_key).await;
+        let response = gate.ask(encrypted_key).await;
         assert!(matches!(response, Ok(())));
     }
 }

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

@@ -0,0 +1,8 @@
+mod common;
+
+#[path = "vault/concurrency.rs"]
+mod concurrency;
+#[path = "vault/lifecycle.rs"]
+mod lifecycle;
+#[path = "vault/storage.rs"]
+mod storage;

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

@@ -1,20 +1,21 @@
-use std::collections::{HashMap, HashSet};
-
+use crate::common;
 use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_server::{
-    actors::keyholder::{CreateNew, Error, KeyHolder},
+    actors::{
+        GlobalActors,
+        vault::{CreateNew, Error, Vault},
+    },
     db::{self, models, schema},
 };
 
 use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper, dsl::sql_query};
 use diesel_async::RunQueryDsl;
 use kameo::actor::{ActorRef, Spawn as _};
+use std::collections::{HashMap, HashSet};
 use tokio::task::JoinSet;
 
-use crate::common;
-
 async fn write_concurrently(
-    actor: ActorRef<KeyHolder>,
+    actor: ActorRef<Vault>,
     prefix: &'static str,
     count: usize,
 ) -> Vec<(i32, Vec<u8>)> {
@@ -44,7 +45,7 @@ async fn write_concurrently(
 #[test_log::test]
 async fn concurrent_create_new_no_duplicate_nonces_() {
     let db = db::create_test_pool().await;
-    let actor = KeyHolder::spawn(common::bootstrapped_keyholder(&db).await);
+    let actor = Vault::spawn(common::bootstrapped_vault(&db).await);
 
     let writes = write_concurrently(actor, "nonce-unique", 32).await;
     assert_eq!(writes.len(), 32);
@@ -66,7 +67,7 @@ async fn concurrent_create_new_no_duplicate_nonces_() {
 #[test_log::test]
 async fn concurrent_create_new_root_nonce_never_moves_backward() {
     let db = db::create_test_pool().await;
-    let actor = KeyHolder::spawn(common::bootstrapped_keyholder(&db).await);
+    let actor = Vault::spawn(common::bootstrapped_vault(&db).await);
 
     write_concurrently(actor, "root-max", 24).await;
 
@@ -94,7 +95,7 @@ async fn concurrent_create_new_root_nonce_never_moves_backward() {
 #[test_log::test]
 async fn insert_failure_does_not_create_partial_row() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
     let root_key_history_id = common::root_key_history_id(&db).await;
 
     let mut conn = db.get().await.unwrap();
@@ -156,12 +157,14 @@ async fn insert_failure_does_not_create_partial_row() {
 #[test_log::test]
 async fn decrypt_roundtrip_after_high_concurrency() {
     let db = db::create_test_pool().await;
-    let actor = KeyHolder::spawn(common::bootstrapped_keyholder(&db).await);
+    let actor = Vault::spawn(common::bootstrapped_vault(&db).await);
 
     let writes = write_concurrently(actor, "roundtrip", 40).await;
     let expected: HashMap<i32, Vec<u8>> = writes.into_iter().collect();
 
-    let mut decryptor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut decryptor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
     decryptor
         .try_unseal(SafeCell::new(b"test-seal-key".to_vec()))
         .await

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

@@ -1,6 +1,10 @@
+use crate::common;
 use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_server::{
-    actors::keyholder::{Error, KeyHolder},
+    actors::{
+        GlobalActors,
+        vault::{Error, Vault},
+    },
     crypto::encryption::v1::{Nonce, ROOT_KEY_TAG},
     db::{self, models, schema},
 };
@@ -8,13 +12,13 @@ use arbiter_server::{
 use diesel::{QueryDsl, SelectableHelper};
 use diesel_async::RunQueryDsl;
 
-use crate::common;
-
 #[tokio::test]
 #[test_log::test]
 async fn test_bootstrap() {
     let db = db::create_test_pool().await;
-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
 
     let seal_key = SafeCell::new(b"test-seal-key".to_vec());
     actor.bootstrap(seal_key).await.unwrap();
@@ -37,7 +41,7 @@ async fn test_bootstrap() {
 #[test_log::test]
 async fn test_bootstrap_rejects_double() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let seal_key2 = SafeCell::new(b"test-seal-key".to_vec());
     let err = actor.bootstrap(seal_key2).await.unwrap_err();
@@ -48,7 +52,9 @@ async fn test_bootstrap_rejects_double() {
 #[test_log::test]
 async fn test_create_new_before_bootstrap_fails() {
     let db = db::create_test_pool().await;
-    let mut actor = KeyHolder::new(db).await.unwrap();
+    let mut actor = Vault::new(db, GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
 
     let err = actor
         .create_new(SafeCell::new(b"data".to_vec()))
@@ -61,7 +67,9 @@ async fn test_create_new_before_bootstrap_fails() {
 #[test_log::test]
 async fn test_decrypt_before_bootstrap_fails() {
     let db = db::create_test_pool().await;
-    let mut actor = KeyHolder::new(db).await.unwrap();
+    let mut actor = Vault::new(db, GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
 
     let err = actor.decrypt(1).await.unwrap_err();
     assert!(matches!(err, Error::NotBootstrapped));
@@ -71,19 +79,21 @@ async fn test_decrypt_before_bootstrap_fails() {
 #[test_log::test]
 async fn test_new_restores_sealed_state() {
     let db = db::create_test_pool().await;
-    let actor = common::bootstrapped_keyholder(&db).await;
+    let actor = common::bootstrapped_vault(&db).await;
     drop(actor);
 
-    let mut actor2 = KeyHolder::new(db).await.unwrap();
+    let mut actor2 = Vault::new(db, GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
     let err = actor2.decrypt(1).await.unwrap_err();
-    assert!(matches!(err, Error::NotBootstrapped));
+    assert!(matches!(err, Error::Sealed));
 }
 
 #[tokio::test]
 #[test_log::test]
 async fn test_unseal_correct_password() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let plaintext = b"survive a restart";
     let aead_id = actor
@@ -92,7 +102,9 @@ async fn test_unseal_correct_password() {
         .unwrap();
     drop(actor);
 
-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
     let seal_key = SafeCell::new(b"test-seal-key".to_vec());
     actor.try_unseal(seal_key).await.unwrap();
 
@@ -104,7 +116,7 @@ async fn test_unseal_correct_password() {
 #[test_log::test]
 async fn test_unseal_wrong_then_correct_password() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let plaintext = b"important data";
     let aead_id = actor
@@ -113,7 +125,9 @@ async fn test_unseal_wrong_then_correct_password() {
         .unwrap();
     drop(actor);
 
-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
 
     let bad_key = SafeCell::new(b"wrong-password".to_vec());
     let err = actor.try_unseal(bad_key).await.unwrap_err();

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

@@ -1,22 +1,20 @@
-use std::collections::HashSet;
-
+use crate::common;
 use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_server::{
-    actors::keyholder::Error,
+    actors::vault::Error,
     crypto::encryption::v1::Nonce,
     db::{self, models, schema},
 };
 
 use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper, dsl::update};
 use diesel_async::RunQueryDsl;
-
-use crate::common;
+use std::collections::HashSet;
 
 #[tokio::test]
 #[test_log::test]
 async fn test_create_decrypt_roundtrip() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let plaintext = b"hello arbiter";
     let aead_id = actor
@@ -32,7 +30,7 @@ async fn test_create_decrypt_roundtrip() {
 #[test_log::test]
 async fn test_decrypt_nonexistent_returns_not_found() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let err = actor.decrypt(9999).await.unwrap_err();
     assert!(matches!(err, Error::NotFound));
@@ -42,7 +40,7 @@ async fn test_decrypt_nonexistent_returns_not_found() {
 #[test_log::test]
 async fn test_ciphertext_differs_across_entries() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let plaintext = b"same content";
     let id1 = actor
@@ -80,7 +78,7 @@ async fn test_ciphertext_differs_across_entries() {
 #[test_log::test]
 async fn test_nonce_never_reused() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let n = 5;
     for i in 0..n {
@@ -124,7 +122,7 @@ async fn test_nonce_never_reused() {
 #[test_log::test]
 async fn broken_db_nonce_format_fails_closed() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
     let root_key_history_id = common::root_key_history_id(&db).await;
 
     let mut conn = db.get().await.unwrap();
@@ -145,7 +143,7 @@ async fn broken_db_nonce_format_fails_closed() {
     assert!(matches!(err, Error::BrokenDatabase));
 
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
     let id = actor
         .create_new(SafeCell::new(b"decrypt target".to_vec()))
         .await

useragent/flutter_rust_bridge.yaml

@@ -0,0 +1,3 @@
+rust_input: crate::api
+rust_root: rust/
+dart_output: lib/src/rust