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

@@ -29,56 +29,37 @@ 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`.
 
 ---
 
 ## Cryptography
 
 ### Authentication
-- **Client protocol:** ed25519
+- **Client protocol:** ML-DSA
 
 ### User-Agent Authentication
 
 User-agent authentication supports multiple signature schemes because platform-provided "hardware-bound" keys do not expose a uniform algorithm across operating systems and hardware.
 
-- **Supported schemes:** RSA, Ed25519, ECDSA (secp256k1)
-- **Why:** the user agent authenticates with keys backed by platform facilities, and those facilities differ by platform
-- **Apple Silicon Secure Enclave / Secure Element:** ECDSA-only in practice
-- **Windows Hello / TPM 2.0:** currently RSA-backed in our integration
-
-This is why the user-agent auth protocol carries an explicit `KeyType`, while the SDK client protocol remains fixed to ed25519.
+- **Supported schemes:** ML-DSA
+- **Why:** Secure Enclave (MacOS) support them natively, on other platforms we could emulate while they roll-out
 
 ### Encryption at Rest
 - **Scheme:** Symmetric AEAD — currently **XChaCha20-Poly1305**

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

@@ -4,44 +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"] }
-smlang = "0.8.0"
-thiserror = "2.0.18"
+alloy = "2.0.0"
 async-trait = "0.1.89"
+base64 = "0.22.1"
+chrono = { version = "0.4.44", features = ["serde"] }
+ed25519-dalek = { version = "3.0.0-pre.6", features = ["rand_core"] }
 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"
+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

@@ -13,14 +13,15 @@ evm = ["dep:alloy"]
 
 [dependencies]
 arbiter-proto.path = "../arbiter-proto"
+arbiter-crypto.path = "../arbiter-crypto"
 alloy = { workspace = true, optional = true }
 tonic.workspace = true
 tonic.features = ["tls-aws-lc"]
 tokio.workspace = true
 tokio-stream.workspace = true
-ed25519-dalek.workspace = true
 thiserror.workspace = true
 http = "1.4.0"
-rustls-webpki = { version = "0.103.10", features = ["aws-lc-rs"] }
+rustls-webpki = { version = "0.103.12", features = ["aws-lc-rs"] }
 async-trait.workspace = true
 rand.workspace = true
+chrono.workspace = true

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

@@ -1,5 +1,10 @@
+use crate::{
+    storage::StorageError,
+    transport::{ClientTransport, next_request_id},
+};
+use arbiter_crypto::authn::{self, CLIENT_CONTEXT, SigningKey};
 use arbiter_proto::{
-    ClientMetadata, format_challenge,
+    ClientMetadata,
     proto::{
         client::{
             ClientRequest,
@@ -14,29 +19,26 @@ use arbiter_proto::{
         shared::ClientInfo as ProtoClientInfo,
     },
 };
-use ed25519_dalek::Signer as _;
 
-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 {
@@ -54,14 +56,14 @@ fn map_auth_result(code: i32) -> AuthError {
 async fn send_auth_challenge_request(
     transport: &mut ClientTransport,
     metadata: ClientMetadata,
-    key: &ed25519_dalek::SigningKey,
-) -> std::result::Result<(), AuthError> {
+    key: &SigningKey,
+) -> Result<(), AuthError> {
     transport
         .send(ClientRequest {
             request_id: next_request_id(),
             payload: Some(ClientRequestPayload::Auth(proto_auth::Request {
                 payload: Some(AuthRequestPayload::ChallengeRequest(AuthChallengeRequest {
-                    pubkey: key.verifying_key().to_bytes().to_vec(),
+                    pubkey: key.public_key().to_bytes(),
                     client_info: Some(ProtoClientInfo {
                         name: metadata.name,
                         description: metadata.description,
@@ -76,7 +78,7 @@ async fn send_auth_challenge_request(
 
 async fn receive_auth_challenge(
     transport: &mut ClientTransport,
-) -> std::result::Result<AuthChallenge, AuthError> {
+) -> Result<AuthChallenge, AuthError> {
     let response = transport
         .recv()
         .await
@@ -95,11 +97,22 @@ async fn receive_auth_challenge(
 
 async fn send_auth_challenge_solution(
     transport: &mut ClientTransport,
-    key: &ed25519_dalek::SigningKey,
+    key: &SigningKey,
     challenge: AuthChallenge,
-) -> std::result::Result<(), AuthError> {
-    let challenge_payload = format_challenge(challenge.nonce, &challenge.pubkey);
-    let signature = key.sign(&challenge_payload).to_bytes().to_vec();
+) -> 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)?
+        .to_bytes();
 
     transport
         .send(ClientRequest {
@@ -114,9 +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
@@ -137,11 +148,11 @@ async fn receive_auth_confirmation(
     }
 }
 
-pub(crate) async fn authenticate(
+pub async fn authenticate(
     transport: &mut ClientTransport,
     metadata: ClientMetadata,
-    key: &ed25519_dalek::SigningKey,
-) -> std::result::Result<(), AuthError> {
+    key: &SigningKey,
+) -> Result<(), AuthError> {
     send_auth_challenge_request(transport, metadata, key).await?;
     let challenge = receive_auth_challenge(transport).await?;
     send_auth_challenge_solution(transport, key, challenge).await?;

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

@@ -1,49 +1,55 @@
-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
     }
@@ -52,7 +58,7 @@ impl ArbiterClient {
         url: ArbiterUrl,
         metadata: ClientMetadata,
         storage: &S,
-    ) -> Result<Self, Error> {
+    ) -> Result<Self, ArbiterClientError> {
         let key = storage.load_or_create()?;
         Self::connect_with_key(url, metadata, key).await
     }
@@ -60,8 +66,8 @@ impl ArbiterClient {
     pub async fn connect_with_key(
         url: ArbiterUrl,
         metadata: ClientMetadata,
-        key: ed25519_dalek::SigningKey,
-    ) -> Result<Self, Error> {
+        key: SigningKey,
+    ) -> Result<Self, ArbiterClientError> {
         let anchor = webpki::anchor_from_trusted_cert(&url.ca_cert)?.to_owned();
         let tls = ClientTlsConfig::new().trust_anchor(anchor);
 
@@ -88,7 +94,8 @@ 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

@@ -1,17 +1,19 @@
+use arbiter_crypto::authn::SigningKey;
 use arbiter_proto::home_path;
+
 use std::path::{Path, PathBuf};
 
 #[derive(Debug, thiserror::Error)]
 pub enum StorageError {
-    #[error("I/O error")]
-    Io(#[from] std::io::Error),
-
     #[error("Invalid signing key length in storage: expected {expected} bytes, got {actual} bytes")]
     InvalidKeyLength { expected: usize, actual: usize },
+
+    #[error("I/O error")]
+    Io(#[from] std::io::Error),
 }
 
 pub trait SigningKeyStorage {
-    fn load_or_create(&self) -> std::result::Result<ed25519_dalek::SigningKey, StorageError>;
+    fn load_or_create(&self) -> Result<SigningKey, StorageError>;
 }
 
 #[derive(Debug, Clone)]
@@ -20,17 +22,17 @@ pub struct FileSigningKeyStorage {
 }
 
 impl FileSigningKeyStorage {
-    pub const DEFAULT_FILE_NAME: &str = "sdk_client_ed25519.key";
+    pub const DEFAULT_FILE_NAME: &str = "sdk_client_ml_dsa.key";
 
     pub fn new(path: impl Into<PathBuf>) -> Self {
         Self { path: path.into() }
     }
 
-    pub fn from_default_location() -> std::result::Result<Self, StorageError> {
+    pub fn from_default_location() -> Result<Self, StorageError> {
         Ok(Self::new(home_path()?.join(Self::DEFAULT_FILE_NAME)))
     }
 
-    fn read_key(path: &Path) -> std::result::Result<ed25519_dalek::SigningKey, StorageError> {
+    fn read_key(path: &Path) -> Result<SigningKey, StorageError> {
         let bytes = std::fs::read(path)?;
         let raw: [u8; 32] =
             bytes
@@ -39,12 +41,12 @@ impl FileSigningKeyStorage {
                     expected: 32,
                     actual: v.len(),
                 })?;
-        Ok(ed25519_dalek::SigningKey::from_bytes(&raw))
+        Ok(SigningKey::from_seed(raw))
     }
 }
 
 impl SigningKeyStorage for FileSigningKeyStorage {
-    fn load_or_create(&self) -> std::result::Result<ed25519_dalek::SigningKey, StorageError> {
+    fn load_or_create(&self) -> Result<SigningKey, StorageError> {
         if let Some(parent) = self.path.parent() {
             std::fs::create_dir_all(parent)?;
         }
@@ -53,8 +55,8 @@ impl SigningKeyStorage for FileSigningKeyStorage {
             return Self::read_key(&self.path);
         }
 
-        let key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-        let raw_key = key.to_bytes();
+        let key = SigningKey::generate();
+        let raw_key = key.to_seed();
 
         // Use create_new to prevent accidental overwrite if another process creates the key first.
         match std::fs::OpenOptions::new()
@@ -103,7 +105,7 @@ mod tests {
             .load_or_create()
             .expect("second load_or_create should read same key");
 
-        assert_eq!(key_a.to_bytes(), key_b.to_bytes());
+        assert_eq!(key_a.to_seed(), key_b.to_seed());
         assert!(path.exists());
 
         std::fs::remove_file(path).expect("temp key file should be removable");
@@ -124,7 +126,7 @@ mod tests {
                 assert_eq!(expected, 32);
                 assert_eq!(actual, 31);
             }
-            other => panic!("unexpected error: {other:?}"),
+            other @ StorageError::Io(_) => panic!("unexpected error: {other:?}"),
         }
 
         std::fs::remove_file(path).expect("temp key file should be removable");

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

@@ -1,16 +1,17 @@
 use arbiter_proto::proto::client::{ClientRequest, ClientResponse};
+
 use std::sync::atomic::{AtomicI32, Ordering};
 use tokio::sync::mpsc;
 
-pub(crate) const BUFFER_LENGTH: usize = 16;
+pub const BUFFER_LENGTH: usize = 16;
 static NEXT_REQUEST_ID: AtomicI32 = AtomicI32::new(1);
 
-pub(crate) fn next_request_id() -> i32 {
+pub fn next_request_id() -> i32 {
     NEXT_REQUEST_ID.fetch_add(1, Ordering::Relaxed)
 }
 
 #[derive(Debug, thiserror::Error)]
-pub(crate) enum ClientSignError {
+pub enum ClientSignError {
     #[error("Transport channel closed")]
     ChannelClosed,
 
@@ -18,27 +19,23 @@ pub(crate) enum ClientSignError {
     ConnectionClosed,
 }
 
-pub(crate) struct ClientTransport {
+pub struct ClientTransport {
     pub(crate) sender: mpsc::Sender<ClientRequest>,
     pub(crate) receiver: tonic::Streaming<ClientResponse>,
 }
 
 impl ClientTransport {
-    pub(crate) async fn send(
-        &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.
 ///
@@ -61,9 +60,9 @@ pub struct ArbiterEvmWallet {
 impl ArbiterEvmWallet {
     #[expect(
         dead_code,
-        reason = "constructor may be used in future extensions, e.g. to support wallet listing"
+        reason = "new will be used in future methods for creating wallets with different parameters"
     )]
-    pub(crate) fn new(transport: Arc<Mutex<ClientTransport>>, address: Address) -> Self {
+    pub(crate) const fn new(transport: Arc<Mutex<ClientTransport>>, address: Address) -> Self {
         Self {
             transport,
             address,
@@ -71,11 +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
     }
@@ -150,6 +150,7 @@ impl TxSigner<Signature> for ArbiterEvmWallet {
             .recv()
             .await
             .map_err(|_| Error::other("failed to receive evm sign transaction response"))?;
+        drop(transport);
 
         if response.request_id != Some(request_id) {
             return Err(Error::other(

server/crates/arbiter-crypto/.gitignore

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

server/crates/arbiter-crypto/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "arbiter-crypto"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+ml-dsa = {workspace = true, optional = true }
+rand = {workspace = true, optional = true}
+memsafe = {version = "0.4.0", optional = true}
+hmac.workspace = true
+alloy.workspace = true
+x-wing = { version = "0.1.0-rc.0", features = ["zeroize"] }
+chrono.workspace = true
+thiserror.workspace = true
+
+[lints]
+workspace = true
+
+[features]
+default = ["authn", "safecell"]
+authn = ["dep:ml-dsa", "dep:rand"]
+safecell = ["dep:memsafe"]

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

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

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

@@ -0,0 +1,252 @@
+use chrono::{DateTime, Utc};
+use hmac::digest::Digest;
+use ml_dsa::{
+    EncodedVerifyingKey, Error, KeyGen, MlDsa87, Seed, Signature as MlDsaSignature,
+    SigningKey as MlDsaSigningKey, VerifyingKey as MlDsaVerifyingKey, signature::Keypair as _,
+};
+use rand::RngExt;
+
+pub static CLIENT_CONTEXT: &[u8] = b"arbiter_client";
+pub static USERAGENT_CONTEXT: &[u8] = b"arbiter_user_agent";
+
+const NONCE_SIZE: usize = 32;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, thiserror::Error)]
+#[error("invalid length: expected {expected} bytes, got {actual} bytes")]
+pub struct InvalidLength {
+    pub expected: usize,
+    pub actual: usize,
+}
+
+#[derive(Debug, Clone)]
+pub struct AuthChallenge {
+    pub nonce: [u8; NONCE_SIZE],
+    pub timestamp: DateTime<Utc>,
+}
+
+impl AuthChallenge {
+    pub fn generate(rng: &mut impl rand::CryptoRng) -> Self {
+        let timestamp = Utc::now();
+        let nonce = {
+            let mut array = [0; NONCE_SIZE];
+            rng.fill(&mut array);
+            array
+        };
+
+        Self { nonce, timestamp }
+    }
+
+    pub fn format(&self) -> Vec<u8> {
+        {
+            let mut buffer = Vec::from(self.nonce);
+
+            let stamp = self
+                .timestamp
+                .timestamp_nanos_opt()
+                .expect("We would be long dead by the time this triggers :)");
+            buffer.extend_from_slice(stamp.to_be_bytes().as_slice());
+
+            buffer
+        }
+    }
+
+    pub fn from_parts(nonce: &[u8], timestamp: i64) -> Result<Self, InvalidLength> {
+        let random_nonce = nonce.as_array().ok_or(InvalidLength {
+            expected: NONCE_SIZE,
+            actual: nonce.len(),
+        })?;
+        Ok(Self {
+            nonce: *random_nonce,
+            timestamp: DateTime::from_timestamp_nanos(timestamp),
+        })
+    }
+}
+
+pub type KeyParams = MlDsa87;
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct PublicKey(Box<MlDsaVerifyingKey<KeyParams>>);
+
+impl crate::hashing::Hashable for PublicKey {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        hasher.update(self.to_bytes());
+    }
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct Signature(Box<MlDsaSignature<KeyParams>>);
+
+#[derive(Debug)]
+pub struct SigningKey(Box<MlDsaSigningKey<KeyParams>>);
+
+impl PublicKey {
+    pub fn to_bytes(&self) -> Vec<u8> {
+        self.0.encode().0.to_vec()
+    }
+
+    #[must_use]
+    pub fn verify(&self, challenge: &AuthChallenge, context: &[u8], signature: &Signature) -> bool {
+        let challenge = challenge.format();
+        self.0
+            .verify_with_context(&challenge, context, &signature.0)
+    }
+}
+
+impl Signature {
+    pub fn to_bytes(&self) -> Vec<u8> {
+        self.0.encode().0.to_vec()
+    }
+}
+
+impl SigningKey {
+    pub fn generate() -> Self {
+        Self(Box::new(KeyParams::key_gen(&mut rand::rng())))
+    }
+
+    pub fn from_seed(seed: [u8; 32]) -> Self {
+        Self(Box::new(KeyParams::from_seed(&Seed::from(seed))))
+    }
+
+    pub fn to_seed(&self) -> [u8; 32] {
+        self.0.to_seed().into()
+    }
+
+    pub fn public_key(&self) -> PublicKey {
+        self.0.verifying_key().into()
+    }
+
+    pub fn sign_message(&self, message: &[u8], context: &[u8]) -> Result<Signature, Error> {
+        self.0
+            .signing_key()
+            .sign_deterministic(message, context)
+            .map(Into::into)
+    }
+
+    pub fn sign_challenge(
+        &self,
+        challenge: &AuthChallenge,
+        context: &[u8],
+    ) -> Result<Signature, Error> {
+        let challenge = challenge.format();
+
+        self.sign_message(&challenge, context)
+    }
+}
+
+impl From<MlDsaVerifyingKey<KeyParams>> for PublicKey {
+    fn from(value: MlDsaVerifyingKey<KeyParams>) -> Self {
+        Self(Box::new(value))
+    }
+}
+
+impl From<MlDsaSignature<KeyParams>> for Signature {
+    fn from(value: MlDsaSignature<KeyParams>) -> Self {
+        Self(Box::new(value))
+    }
+}
+
+impl From<MlDsaSigningKey<KeyParams>> for SigningKey {
+    fn from(value: MlDsaSigningKey<KeyParams>) -> Self {
+        Self(Box::new(value))
+    }
+}
+
+impl TryFrom<Vec<u8>> for PublicKey {
+    type Error = ();
+
+    fn try_from(value: Vec<u8>) -> Result<Self, Self::Error> {
+        Self::try_from(value.as_slice())
+    }
+}
+
+impl TryFrom<&'_ [u8]> for PublicKey {
+    type Error = ();
+
+    fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
+        let encoded = EncodedVerifyingKey::<KeyParams>::try_from(value).map_err(|_| ())?;
+        Ok(Self(Box::new(MlDsaVerifyingKey::decode(&encoded))))
+    }
+}
+
+impl TryFrom<Vec<u8>> for Signature {
+    type Error = ();
+
+    fn try_from(value: Vec<u8>) -> Result<Self, Self::Error> {
+        Self::try_from(value.as_slice())
+    }
+}
+
+impl TryFrom<&'_ [u8]> for Signature {
+    type Error = ();
+
+    fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
+        MlDsaSignature::try_from(value)
+            .map(|sig| Self(Box::new(sig)))
+            .map_err(|_| ())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use ml_dsa::{KeyGen, MlDsa87, signature::Keypair as _};
+
+    use crate::authn::AuthChallenge;
+
+    use super::{CLIENT_CONTEXT, PublicKey, Signature, SigningKey, USERAGENT_CONTEXT};
+
+    #[test]
+    fn public_key_round_trip_decodes() {
+        let key = MlDsa87::key_gen(&mut rand::rng());
+        let encoded = PublicKey::from(key.verifying_key()).to_bytes();
+
+        let decoded = PublicKey::try_from(encoded.as_slice()).expect("public key should decode");
+
+        assert_eq!(decoded, PublicKey::from(key.verifying_key()));
+    }
+
+    #[test]
+    fn signature_round_trip_decodes() {
+        let key = SigningKey::generate();
+        let signature = key
+            .sign_message(b"challenge", CLIENT_CONTEXT)
+            .expect("signature should be created");
+
+        let decoded =
+            Signature::try_from(signature.to_bytes().as_slice()).expect("signature should decode");
+
+        assert_eq!(decoded, signature);
+    }
+
+    #[test]
+    fn challenge_verification_uses_context_and_canonical_key_bytes() {
+        let key = SigningKey::generate();
+        let public_key = key.public_key();
+        let challenge = AuthChallenge::generate(&mut rand::rng());
+        let signature = key
+            .sign_challenge(&challenge, CLIENT_CONTEXT)
+            .expect("signature should be created");
+
+        assert!(public_key.verify(&challenge, CLIENT_CONTEXT, &signature));
+        assert!(!public_key.verify(&challenge, USERAGENT_CONTEXT, &signature));
+    }
+
+    #[test]
+    fn signing_key_round_trip_seed_preserves_public_key_and_signing() {
+        let original = SigningKey::generate();
+        let restored = SigningKey::from_seed(original.to_seed());
+
+        assert_eq!(restored.public_key(), original.public_key());
+
+        let challenge = AuthChallenge::generate(&mut rand::rng());
+
+        let signature = restored
+            .sign_challenge(&challenge, CLIENT_CONTEXT)
+            .expect("signature should be created");
+
+        assert!(
+            restored
+                .public_key()
+                .verify(&challenge, CLIENT_CONTEXT, &signature)
+        );
+    }
+}

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

@@ -1,21 +1,26 @@
-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",
+    note = "for types from other crates check whether the crate offers a `Hashable` implementation"
+)]
 pub trait Hashable {
     fn hash<H: Digest>(&self, hasher: &mut H);
 }
 
 macro_rules! impl_numeric {
-($($t:ty),*) => {
-    $(
-        impl Hashable for $t {
-            fn hash<H: Digest>(&self, hasher: &mut H) {
-                hasher.update(&self.to_be_bytes());
+    ($($t:ty),*) => {
+        $(
+            impl Hashable for $t {
+                fn hash<H: Digest>(&self, hasher: &mut H) {
+                    hasher.update(&self.to_be_bytes());
+                }
             }
-        }
-    )*
-};
+        )*
+    };
 }
 
 impl_numeric!(u8, u16, u32, u64, i8, i16, i32, i64);
@@ -45,7 +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

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

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

@@ -1,7 +1,9 @@
-use std::ops::{Deref, DerefMut};
-use std::{any::type_name, fmt};
-
 use memsafe::MemSafe;
+use std::{
+    any::type_name,
+    fmt,
+    ops::{Deref, DerefMut},
+};
 
 pub trait SafeCellHandle<T> {
     type CellRead<'a>: Deref<Target = T>
@@ -29,7 +31,7 @@ pub trait SafeCellHandle<T> {
         let mut cell = Self::new(T::default());
         {
             let mut handle = cell.write();
-            f(handle.deref_mut());
+            f(&mut *handle);
         }
         cell
     }
@@ -105,6 +107,11 @@ impl<T> SafeCellHandle<T> for MemSafeCell<T> {
 
 fn abort_memory_breach(action: &str, err: &memsafe::error::MemoryError) -> ! {
     eprintln!("fatal {action}: {err}");
+    // SAFETY: Intentionally cause a segmentation fault to prevent further execution in a compromised state.
+    unsafe {
+        let unsafe_pointer = std::ptr::null_mut::<u8>();
+        std::ptr::write_volatile(unsafe_pointer, 0);
+    }
     std::process::abort();
 }
 

server/crates/arbiter-macros/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "arbiter-macros"
+version = "0.1.0"
+edition = "2024"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+proc-macro2 = "1.0"
+quote = "1.0"
+syn = { version = "2.0", features = ["derive", "fold", "full", "visit-mut"] }
+
+[dev-dependencies]
+arbiter-crypto = { path = "../arbiter-crypto" }
+
+[lints]
+workspace = true

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

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

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

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

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

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

server/crates/arbiter-proto/Cargo.toml

@@ -17,7 +17,7 @@ url = "2.5.8"
 miette.workspace = true
 thiserror.workspace = true
 rustls-pki-types.workspace = true
-base64 = "0.22.1"
+base64.workspace = true
 prost-types.workspace = true
 tracing.workspace = true
 async-trait.workspace = true

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

@@ -1,8 +1,6 @@
 pub mod transport;
 pub mod url;
 
-use base64::{Engine, prelude::BASE64_STANDARD};
-
 pub mod proto {
     tonic::include_proto!("arbiter");
 
@@ -84,8 +82,3 @@ pub fn home_path() -> Result<std::path::PathBuf, std::io::Error> {
 
     Ok(arbiter_home)
 }
-
-pub fn format_challenge(nonce: i32, pubkey: &[u8]) -> Vec<u8> {
-    let concat_form = format!("{}:{}", nonce, BASE64_STANDARD.encode(pubkey));
-    concat_form.into_bytes()
-}

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

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

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

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

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

@@ -1,7 +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

@@ -16,9 +16,9 @@ diesel-async = { version = "0.8.0", features = [
     "sqlite",
     "tokio",
 ] }
-ed25519-dalek.workspace = true
-ed25519-dalek.features = ["serde"]
 arbiter-proto.path = "../arbiter-proto"
+arbiter-crypto.path = "../arbiter-crypto"
+arbiter-macros.path = "../arbiter-macros"
 tracing.workspace = true
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 tonic.workspace = true
@@ -37,21 +37,15 @@ dashmap = "6.1.0"
 rand.workspace = true
 rcgen.workspace = true
 chrono.workspace = true
-memsafe = "0.4.0"
 zeroize = { version = "1.8.2", features = ["std", "simd"] }
 kameo.workspace = true
-x25519-dalek.workspace = true
 chacha20poly1305 = { version = "0.10.1", features = ["std"] }
 argon2 = { version = "0.5.3", features = ["zeroize"] }
 restructed = "0.2.2"
 strum = { version = "0.28.0", features = ["derive"] }
 pem = "3.0.6"
-k256.workspace = true
-k256.features = ["serde"]
-rsa.workspace = true
-rsa.features = ["serde"]
 sha2.workspace = true
-hmac = "0.12"
+hmac.workspace = true
 spki.workspace = true
 alloy.workspace = true
 prost-types.workspace = true
@@ -61,11 +55,14 @@ anyhow = "1.0.102"
 serde_with = "3.18.0"
 mutants.workspace = true
 subtle = "2.6.1"
-macro_rules_attribute = "0.2.2"
-paste = "1.0.15"
+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), -- 1=Ed25519, 2=ECDSA(secp256k1)
     created_at integer not null default(unixepoch ('now')),
     updated_at integer not null default(unixepoch ('now'))
 ) STRICT;
-create unique index if not exists uniq_useragent_client_public_key on useragent_client (public_key, key_type);
+create unique index if not exists uniq_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) => {
-                let expected_bytes = expected.as_bytes();
-                let token_bytes = token.as_bytes();
+        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,
-        }
+            let choice = expected_bytes.ct_eq(token_bytes);
+            bool::from(choice)
+        })
     }
 
     #[message]

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

@@ -1,14 +1,6 @@
-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},
-    crypto::integrity::{self, Integrable, Verified, hashing::Hashable},
+    actors::vault::{CreateNew, Decrypt, Vault},
+    crypto::integrity,
     db::{
         DatabaseError, DatabasePool,
         models::{self},
@@ -21,68 +13,49 @@ use crate::{
             ether_transfer::EtherTransfer, token_transfers::TokenTransfer,
         },
     },
-    safe_cell::{SafeCell, SafeCellHandle as _},
 };
+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;
 
-/// Hashable structure for wallet integrity protection.
-/// Binds the encrypted private key to the wallet address using HMAC.
-pub struct EvmWalletIntegrity {
-    pub address: Vec<u8>,       // 20-byte Ethereum address
-    pub aead_encrypted_id: i32, // Reference to encrypted key material
-}
-
-impl Hashable for EvmWalletIntegrity {
-    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
-        hasher.update(&self.address);
-        hasher.update(self.aead_encrypted_id.to_be_bytes());
-    }
-}
-
-impl Integrable for EvmWalletIntegrity {
-    const KIND: &'static str = "evm_wallet";
-}
-
 #[derive(Debug, thiserror::Error)]
 pub enum SignTransactionError {
     #[error("Wallet not found")]
     WalletNotFound,
 
-    #[error("Wallet integrity check failed")]
-    WalletIntegrityCheckFailed,
-
-    #[error(
-        "Decrypted key does not correspond to wallet address (CRITICAL: possible key substitution attack)"
-    )]
-    KeyAddressMismatch,
-
     #[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),
 
     #[error("Policy error: {0}")]
     Vet(#[from] evm::VetError),
-
-    #[error("Integrity error: {0}")]
-    Integrity(#[from] integrity::Error),
 }
 
 #[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),
@@ -93,20 +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,
@@ -117,19 +90,19 @@ impl EvmActor {
 #[messages]
 impl EvmActor {
     #[message]
-    pub async fn generate(&mut self) -> Result<(Verified<i32>, Address), Error> {
+    pub async fn generate(&mut self) -> Result<(i32, Address), Error> {
         let (mut key_cell, address) = safe_signer::generate(&mut self.rng);
 
         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: i32 = insert_into(schema::evm_wallet::table)
+        let wallet_id = insert_into(schema::evm_wallet::table)
             .values(&models::NewEvmWallet {
                 address: address.as_slice().to_vec(),
                 aead_encrypted_id: aead_id,
@@ -139,17 +112,7 @@ impl EvmActor {
             .await
             .map_err(DatabaseError::from)?;
 
-        // Sign integrity envelope to bind encrypted key to wallet address
-        let wallet_integrity = EvmWalletIntegrity {
-            address: address.as_slice().to_vec(),
-            aead_encrypted_id: aead_id,
-        };
-        let verified_wallet_id =
-            integrity::sign_entity(&mut conn, &self.keyholder, &wallet_integrity, wallet_id)
-                .await?
-                .unqualify_origin();
-
-        Ok((verified_wallet_id, address))
+        Ok((wallet_id, address))
     }
 
     #[message]
@@ -175,7 +138,7 @@ impl EvmActor {
         &mut self,
         basic: SharedGrantSettings,
         grant: SpecificGrant,
-    ) -> Result<integrity::Verified<i32>, Error> {
+    ) -> Result<i32, Error> {
         match grant {
             SpecificGrant::EtherTransfer(settings) => self
                 .engine
@@ -197,9 +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 {
@@ -246,23 +210,9 @@ impl EvmActor {
             .optional()
             .map_err(DatabaseError::from)?
             .ok_or(SignTransactionError::WalletNotFound)?;
-
-        // Verify wallet integrity envelope
-        let wallet = integrity::verify_entity(
-            &mut conn,
-            &self.keyholder,
-            EvmWalletIntegrity {
-                address: wallet.address.clone(),
-                aead_encrypted_id: wallet.aead_encrypted_id,
-            },
-            wallet.id,
-        )
-        .await
-        .map_err(|_| SignTransactionError::WalletIntegrityCheckFailed)?;
-
         let wallet_access = schema::evm_wallet_access::table
             .select(models::EvmWalletAccess::as_select())
-            .filter(schema::evm_wallet_access::wallet_id.eq(wallet.entity_id))
+            .filter(schema::evm_wallet_access::wallet_id.eq(wallet.id))
             .filter(schema::evm_wallet_access::client_id.eq(client_id))
             .first(&mut conn)
             .await
@@ -295,23 +245,9 @@ impl EvmActor {
             .optional()
             .map_err(DatabaseError::from)?
             .ok_or(SignTransactionError::WalletNotFound)?;
-
-        // Verify wallet integrity envelope to ensure encrypted key is bound to address
-        let wallet = integrity::verify_entity(
-            &mut conn,
-            &self.keyholder,
-            EvmWalletIntegrity {
-                address: wallet.address.clone(),
-                aead_encrypted_id: wallet.aead_encrypted_id,
-            },
-            wallet.id,
-        )
-        .await
-        .map_err(|_| SignTransactionError::WalletIntegrityCheckFailed)?;
-
         let wallet_access = schema::evm_wallet_access::table
             .select(models::EvmWalletAccess::as_select())
-            .filter(schema::evm_wallet_access::wallet_id.eq(wallet.entity_id))
+            .filter(schema::evm_wallet_access::wallet_id.eq(wallet.id))
             .filter(schema::evm_wallet_access::client_id.eq(client_id))
             .first(&mut conn)
             .await
@@ -321,26 +257,19 @@ 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)?;
 
-        // Verify that the decrypted key's derived address matches the wallet address
-        // This prevents an attacker from substituting one wallet's key with another's even if they compromised the DB
-        if signer.address() != wallet_address {
-            return Err(SignTransactionError::KeyAddressMismatch);
-        }
-
         self.engine
             .evaluate_transaction(wallet_access, transaction.clone(), RunKind::Execution)
             .await?;
 
-        use alloy::network::TxSignerSync as _;
         Ok(signer.sign_transaction_sync(&mut transaction)?)
     }
 }

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

@@ -1,16 +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

@@ -1,347 +0,0 @@
-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::{AuthPublicKey, UserAgentConnection, UserAgentCredentials, auth::Outbound},
-    },
-    crypto::integrity,
-    db::{DatabasePool, schema::useragent_client},
-};
-
-pub struct ChallengeRequest {
-    pub pubkey: AuthPublicKey,
-}
-
-pub struct BootstrapAuthRequest {
-    pub pubkey: AuthPublicKey,
-    pub token: String,
-}
-
-pub struct ChallengeContext {
-    pub challenge_nonce: i32,
-    pub key: AuthPublicKey,
-}
-
-pub struct ChallengeSolution {
-    pub solution: Vec<u8>,
-}
-
-smlang::statemachine!(
-    name: Auth,
-    custom_error: true,
-    transitions: {
-        *Init + AuthRequest(ChallengeRequest) / async prepare_challenge = SentChallenge(ChallengeContext),
-        Init + BootstrapAuthRequest(BootstrapAuthRequest) / async verify_bootstrap_token = AuthOk(AuthPublicKey),
-        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) / async verify_solution = AuthOk(AuthPublicKey),
-    }
-);
-
-/// Returns the current nonce, ready to use for the challenge nonce.
-async fn get_current_nonce_and_id(
-    db: &DatabasePool,
-    key: &AuthPublicKey,
-) -> Result<(i32, i32), Error> {
-    let mut db_conn = db
-        .get()
-        .await
-        .map_err(|e| Error::internal("Database unavailable", &e))?;
-    db_conn
-        .exclusive_transaction(|conn| {
-            Box::pin(async move {
-                useragent_client::table
-                    .filter(useragent_client::public_key.eq(key.to_stored_bytes()))
-                    .filter(useragent_client::key_type.eq(key.key_type()))
-                    .select((useragent_client::id, useragent_client::nonce))
-                    .first::<(i32, i32)>(conn)
-                    .await
-            })
-        })
-        .await
-        .optional()
-        .map_err(|e| Error::internal("Database operation failed", &e))?
-        .ok_or_else(|| {
-            error!(?key, "Public key not found in database");
-            Error::UnregisteredPublicKey
-        })
-}
-
-async fn verify_integrity(
-    db: &DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
-    pubkey: &AuthPublicKey,
-) -> Result<(), Error> {
-    let mut db_conn = db
-        .get()
-        .await
-        .map_err(|e| Error::internal("Database unavailable", &e))?;
-
-    let (id, nonce) = get_current_nonce_and_id(db, pubkey).await?;
-
-    let attestation_status = integrity::check_entity_attestation(
-        &mut db_conn,
-        keyholder,
-        &UserAgentCredentials {
-            pubkey: pubkey.clone(),
-            nonce,
-        },
-        id,
-    )
-    .await
-    .map_err(|e| Error::internal("Integrity verification failed", &e))?;
-
-    use integrity::AttestationStatus as AS;
-    // SAFETY (policy): challenge auth must work in both vault states.
-    // While sealed, integrity checks can only report `Unavailable` because key material is not
-    // accessible. While unsealed, the same check can report `Attested`.
-    // This path intentionally accepts both outcomes to keep challenge auth available across state
-    // transitions; stricter verification is enforced in sensitive post-auth flows.
-    match attestation_status {
-        AS::Attested | AS::Unavailable => Ok(()),
-    }
-}
-
-async fn create_nonce(
-    db: &DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
-    pubkey: &AuthPublicKey,
-) -> Result<i32, Error> {
-    let mut db_conn = db
-        .get()
-        .await
-        .map_err(|e| Error::internal("Database unavailable", &e))?;
-    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_stored_bytes()))
-                    .filter(useragent_client::key_type.eq(pubkey.key_type()))
-                    .set(useragent_client::nonce.eq(useragent_client::nonce + 1))
-                    .returning((useragent_client::id, useragent_client::nonce))
-                    .get_result(conn)
-                    .await
-                    .map_err(|e| Error::internal("Database operation failed", &e))?;
-
-                integrity::sign_entity(
-                    conn,
-                    keyholder,
-                    &UserAgentCredentials {
-                        pubkey: pubkey.clone(),
-                        nonce: new_nonce,
-                    },
-                    id,
-                )
-                .await
-                .map_err(|e| Error::internal("Database error", &e))?
-                .drop_verification_provenance();
-
-                Result::<_, Error>::Ok(new_nonce)
-            })
-        })
-        .await?;
-    Ok(new_nonce)
-}
-
-async fn register_key(
-    db: &DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
-    pubkey: &AuthPublicKey,
-) -> Result<(), Error> {
-    let pubkey_bytes = pubkey.to_stored_bytes();
-    let key_type = pubkey.key_type();
-    let mut conn = db
-        .get()
-        .await
-        .map_err(|e| Error::internal("Database unavailable", &e))?;
-
-    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),
-                    useragent_client::key_type.eq(key_type),
-                ))
-                .returning(useragent_client::id)
-                .get_result(conn)
-                .await
-                .map_err(|e| Error::internal("Database operation failed", &e))?;
-
-            if let Err(e) = integrity::sign_entity(
-                conn,
-                keyholder,
-                &UserAgentCredentials {
-                    pubkey: pubkey.clone(),
-                    nonce: NONCE_START,
-                },
-                id,
-            )
-            .await
-            {
-                match e {
-                    integrity::Error::Keyholder(
-                        crate::actors::keyholder::Error::NotBootstrapped,
-                    ) => {
-                        // IMPORTANT: bootstrap-token auth must work before the vault has a root key.
-                        // We intentionally allow creating the DB row first and backfill envelopes
-                        // after bootstrap/unseal to keep the bootstrap flow possible.
-                    }
-                    other => {
-                        return Err(Error::internal("Failed to register public key", &other));
-                    }
-                }
-            }
-
-            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<AuthPublicKey, Self::Error> {
-        let token_ok: bool = self
-            .conn
-            .actors
-            .bootstrapper
-            .ask(ConsumeToken {
-                token: token.clone(),
-            })
-            .await
-            .map_err(|e| Error::internal("Failed to consume bootstrap token", &e))?;
-
-        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<AuthPublicKey, Self::Error> {
-        let formatted = arbiter_proto::format_challenge(*challenge_nonce, &key.to_stored_bytes());
-
-        let valid = match key {
-            AuthPublicKey::Ed25519(vk) => {
-                let sig = solution.as_slice().try_into().map_err(|_| {
-                    error!(?solution, "Invalid Ed25519 signature length");
-                    Error::InvalidChallengeSolution
-                })?;
-                vk.verify_strict(&formatted, &sig).is_ok()
-            }
-            AuthPublicKey::EcdsaSecp256k1(vk) => {
-                use k256::ecdsa::signature::Verifier as _;
-                let sig = k256::ecdsa::Signature::try_from(solution.as_slice()).map_err(|_| {
-                    error!(?solution, "Invalid ECDSA signature bytes");
-                    Error::InvalidChallengeSolution
-                })?;
-                vk.verify(&formatted, &sig).is_ok()
-            }
-            AuthPublicKey::Rsa(pk) => {
-                use rsa::signature::Verifier as _;
-                let verifying_key = rsa::pss::VerifyingKey::<sha2::Sha256>::new(pk.clone());
-                let sig = rsa::pss::Signature::try_from(solution.as_slice()).map_err(|_| {
-                    error!(?solution, "Invalid RSA signature bytes");
-                    Error::InvalidChallengeSolution
-                })?;
-                verifying_key.verify(&formatted, &sig).is_ok()
-            }
-        };
-
-        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

@@ -1,120 +0,0 @@
-use crate::{
-    actors::{GlobalActors, client::ClientProfile},
-    crypto::integrity::Integrable,
-    db::{self, models::KeyType},
-};
-
-/// Abstraction over Ed25519 / ECDSA-secp256k1 / RSA public keys used during the auth handshake.
-#[derive(Clone, Debug)]
-pub enum AuthPublicKey {
-    Ed25519(ed25519_dalek::VerifyingKey),
-    /// Compressed SEC1 public key; signature bytes are raw 64-byte (r||s).
-    EcdsaSecp256k1(k256::ecdsa::VerifyingKey),
-    /// RSA-2048+ public key (Windows Hello / KeyCredentialManager); signature bytes are PSS+SHA-256.
-    Rsa(rsa::RsaPublicKey),
-}
-
-#[derive(Debug)]
-pub struct UserAgentCredentials {
-    pub pubkey: AuthPublicKey,
-    pub nonce: i32,
-}
-
-impl Integrable for UserAgentCredentials {
-    const KIND: &'static str = "useragent_credentials";
-}
-
-impl AuthPublicKey {
-    /// Canonical bytes stored in DB and echoed back in the challenge.
-    /// Ed25519: raw 32 bytes. ECDSA: SEC1 compressed 33 bytes. RSA: DER-encoded SPKI.
-    pub fn to_stored_bytes(&self) -> Vec<u8> {
-        match self {
-            AuthPublicKey::Ed25519(k) => k.to_bytes().to_vec(),
-            // SEC1 compressed (33 bytes) is the natural compact format for secp256k1
-            AuthPublicKey::EcdsaSecp256k1(k) => k.to_encoded_point(true).as_bytes().to_vec(),
-            AuthPublicKey::Rsa(k) => {
-                use rsa::pkcs8::EncodePublicKey as _;
-                #[allow(clippy::expect_used)]
-                k.to_public_key_der()
-                    .expect("rsa SPKI encoding is infallible")
-                    .to_vec()
-            }
-        }
-    }
-
-    pub fn key_type(&self) -> KeyType {
-        match self {
-            AuthPublicKey::Ed25519(_) => KeyType::Ed25519,
-            AuthPublicKey::EcdsaSecp256k1(_) => KeyType::EcdsaSecp256k1,
-            AuthPublicKey::Rsa(_) => KeyType::Rsa,
-        }
-    }
-}
-
-impl TryFrom<(KeyType, Vec<u8>)> for AuthPublicKey {
-    type Error = &'static str;
-
-    fn try_from(value: (KeyType, Vec<u8>)) -> Result<Self, Self::Error> {
-        let (key_type, bytes) = value;
-        match key_type {
-            KeyType::Ed25519 => {
-                let bytes: [u8; 32] = bytes.try_into().map_err(|_| "invalid Ed25519 key length")?;
-                let key = ed25519_dalek::VerifyingKey::from_bytes(&bytes)
-                    .map_err(|_e| "invalid Ed25519 key")?;
-                Ok(AuthPublicKey::Ed25519(key))
-            }
-            KeyType::EcdsaSecp256k1 => {
-                let point =
-                    k256::EncodedPoint::from_bytes(&bytes).map_err(|_e| "invalid ECDSA key")?;
-                let key = k256::ecdsa::VerifyingKey::from_encoded_point(&point)
-                    .map_err(|_e| "invalid ECDSA key")?;
-                Ok(AuthPublicKey::EcdsaSecp256k1(key))
-            }
-            KeyType::Rsa => {
-                use rsa::pkcs8::DecodePublicKey as _;
-                let key = rsa::RsaPublicKey::from_public_key_der(&bytes)
-                    .map_err(|_e| "invalid RSA key")?;
-                Ok(AuthPublicKey::Rsa(key))
-            }
-        }
-    }
-}
-
-// Messages, sent by user agent to connection client without having a request
-#[derive(Debug)]
-pub enum OutOfBand {
-    ClientConnectionRequest { profile: ClientProfile },
-    ClientConnectionCancel { pubkey: ed25519_dalek::VerifyingKey },
-}
-
-pub struct UserAgentConnection {
-    pub(crate) db: db::DatabasePool,
-    pub(crate) actors: GlobalActors,
-}
-
-impl UserAgentConnection {
-    pub fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
-        Self { db, actors }
-    }
-}
-
-pub mod auth;
-pub mod session;
-
-pub use auth::authenticate;
-pub use session::UserAgentSession;
-
-use crate::crypto::integrity::hashing::Hashable;
-
-impl Hashable for AuthPublicKey {
-    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
-        hasher.update(self.to_stored_bytes());
-    }
-}
-
-impl Hashable for UserAgentCredentials {
-    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
-        self.pubkey.hash(hasher);
-        self.nonce.hash(hasher);
-    }
-}

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

@@ -1,592 +0,0 @@
-use std::sync::Mutex;
-
-use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
-use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
-use diesel::{ExpressionMethods as _, QueryDsl as _, SelectableHelper};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::error::SendError;
-use kameo::messages;
-use kameo::prelude::Context;
-use tracing::{error, info};
-use x25519_dalek::{EphemeralSecret, PublicKey};
-
-use crate::actors::keyholder::KeyHolderState;
-use crate::actors::user_agent::session::Error;
-use crate::db::models::{
-    EvmWalletAccess, NewEvmWalletAccess, ProgramClient, ProgramClientMetadata,
-};
-use crate::evm::policies::{Grant, SpecificGrant};
-use crate::safe_cell::SafeCell;
-use crate::{
-    actors::flow_coordinator::client_connect_approval::ClientApprovalAnswer,
-    crypto::integrity::{self, Verified},
-};
-use crate::{
-    actors::{
-        evm::{
-            ClientSignTransaction, Generate, ListWallets, SignTransactionError as EvmSignError,
-            UseragentCreateGrant, UseragentDeleteGrant, UseragentListGrants,
-        },
-        keyholder::{self, Bootstrap, TryUnseal},
-        user_agent::session::{
-            UserAgentSession,
-            state::{UnsealContext, UserAgentEvents, UserAgentStates},
-        },
-        user_agent::{AuthPublicKey, UserAgentCredentials},
-    },
-    db::schema::useragent_client,
-    safe_cell::SafeCellHandle as _,
-};
-
-fn is_vault_sealed_from_evm<M>(err: &SendError<M, crate::actors::evm::Error>) -> bool {
-    matches!(
-        err,
-        SendError::HandlerError(crate::actors::evm::Error::Keyholder(
-            keyholder::Error::NotBootstrapped
-        )) | SendError::HandlerError(crate::actors::evm::Error::Integrity(
-            crate::crypto::integrity::Error::Keyholder(keyholder::Error::NotBootstrapped)
-        ))
-    )
-}
-
-impl UserAgentSession {
-    async fn backfill_useragent_integrity(&self) -> Result<(), Error> {
-        let mut conn = self.props.db.get().await?;
-        let keyholder = self.props.actors.key_holder.clone();
-
-        conn.transaction(|conn| {
-            Box::pin(async move {
-                let rows: Vec<(i32, i32, Vec<u8>, crate::db::models::KeyType)> =
-                    useragent_client::table
-                        .select((
-                            useragent_client::id,
-                            useragent_client::nonce,
-                            useragent_client::public_key,
-                            useragent_client::key_type,
-                        ))
-                        .load(conn)
-                        .await?;
-
-                for (id, nonce, public_key, key_type) in rows {
-                    let pubkey = AuthPublicKey::try_from((key_type, public_key)).map_err(|e| {
-                        Error::internal(format!("Invalid user-agent key in db: {e}"))
-                    })?;
-
-                    integrity::sign_entity(
-                        conn,
-                        &keyholder,
-                        &UserAgentCredentials { pubkey, nonce },
-                        id,
-                    )
-                    .await
-                    .map_err(|e| {
-                        Error::internal(format!("Failed to backfill user-agent integrity: {e}"))
-                    })?
-                    .drop_verification_provenance();
-                }
-
-                Result::<_, Error>::Ok(())
-            })
-        })
-        .await?;
-
-        Ok(())
-    }
-
-    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(_) => {
-                self.backfill_useragent_integrity().await?;
-                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(_) => {
-                self.backfill_useragent_integrity().await?;
-                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<(Verified<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>>, GrantMutationError> {
-        match self.props.actors.evm.ask(UseragentListGrants {}).await {
-            Ok(grants) => Ok(grants),
-            Err(err) if is_vault_sealed_from_evm(&err) => Err(GrantMutationError::VaultSealed),
-            Err(err) => {
-                error!(?err, "EVM grant list failed");
-                Err(GrantMutationError::Internal)
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_grant_create(
-        &mut self,
-        basic: crate::evm::policies::SharedGrantSettings,
-        grant: crate::evm::policies::SpecificGrant,
-    ) -> Result<Verified<i32>, GrantMutationError> {
-        match self
-            .props
-            .actors
-            .evm
-            .ask(UseragentCreateGrant { basic, grant })
-            .await
-        {
-            Ok(grant_id) => Ok(grant_id),
-            Err(err) if is_vault_sealed_from_evm(&err) => Err(GrantMutationError::VaultSealed),
-            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: grant_id,
-            })
-            .await
-        {
-            Ok(()) => Ok(()),
-            Err(err) if is_vault_sealed_from_evm(&err) => Err(GrantMutationError::VaultSealed),
-            Err(err) => {
-                error!(?err, "EVM grant delete failed");
-                Err(GrantMutationError::Internal)
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_sign_transaction(
-        &mut self,
-        client_id: i32,
-        wallet_address: Address,
-        transaction: TxEip1559,
-    ) -> Result<Signature, SignTransactionError> {
-        match self
-            .props
-            .actors
-            .evm
-            .ask(ClientSignTransaction {
-                client_id,
-                wallet_address,
-                transaction,
-            })
-            .await
-        {
-            Ok(signature) => Ok(signature),
-            Err(SendError::HandlerError(EvmSignError::Vet(vet_error))) => {
-                Err(SignTransactionError::Vet(vet_error))
-            }
-            Err(err) => {
-                error!(?err, "EVM sign transaction failed in user-agent session");
-                Err(SignTransactionError::Internal)
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_grant_evm_wallet_access(
-        &mut self,
-        entries: Vec<NewEvmWalletAccess>,
-    ) -> Result<(), Error> {
-        let mut conn = self.props.db.get().await?;
-        conn.transaction(|conn| {
-            Box::pin(async move {
-                use crate::db::schema::evm_wallet_access;
-
-                for entry in entries {
-                    diesel::insert_into(evm_wallet_access::table)
-                        .values(&entry)
-                        .on_conflict_do_nothing()
-                        .execute(conn)
-                        .await?;
-                }
-
-                Result::<_, Error>::Ok(())
-            })
-        })
-        .await?;
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_revoke_evm_wallet_access(
-        &mut self,
-        entries: Vec<i32>,
-    ) -> Result<(), Error> {
-        let mut conn = self.props.db.get().await?;
-        conn.transaction(|conn| {
-            Box::pin(async move {
-                use crate::db::schema::evm_wallet_access;
-                for entry in entries {
-                    diesel::delete(evm_wallet_access::table)
-                        .filter(evm_wallet_access::wallet_id.eq(entry))
-                        .execute(conn)
-                        .await?;
-                }
-
-                Result::<_, Error>::Ok(())
-            })
-        })
-        .await?;
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_list_wallet_access(
-        &mut self,
-    ) -> Result<Vec<EvmWalletAccess>, Error> {
-        let mut conn = self.props.db.get().await?;
-        use crate::db::schema::evm_wallet_access;
-        let access_entries = evm_wallet_access::table
-            .select(EvmWalletAccess::as_select())
-            .load::<_>(&mut conn)
-            .await?;
-        Ok(access_entries)
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message(ctx)]
-    pub(crate) async fn handle_new_client_approve(
-        &mut self,
-        approved: bool,
-        pubkey: ed25519_dalek::VerifyingKey,
-        ctx: &mut Context<Self, Result<(), Error>>,
-    ) -> Result<(), Error> {
-        let pending_approval = match self.pending_client_approvals.remove(&pubkey) {
-            Some(approval) => approval,
-            None => {
-                error!("Received client connection response for unknown client");
-                return Err(Error::internal("Unknown client in connection response"));
-            }
-        };
-
-        pending_approval
-            .controller
-            .tell(ClientApprovalAnswer { approved })
-            .await
-            .map_err(|err| {
-                error!(
-                    ?err,
-                    "Failed to send client approval response to controller"
-                );
-                Error::internal("Failed to send client approval response to controller")
-            })?;
-
-        ctx.actor_ref().unlink(&pending_approval.controller).await;
-
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_sdk_client_list(
-        &mut self,
-    ) -> Result<Vec<(ProgramClient, ProgramClientMetadata)>, Error> {
-        use crate::db::schema::{client_metadata, program_client};
-        let mut conn = self.props.db.get().await?;
-
-        let clients = program_client::table
-            .inner_join(client_metadata::table)
-            .select((
-                ProgramClient::as_select(),
-                ProgramClientMetadata::as_select(),
-            ))
-            .load::<(ProgramClient, ProgramClientMetadata)>(&mut conn)
-            .await?;
-
-        Ok(clients)
-    }
-}

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

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

server/crates/arbiter-server/src/actors/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

@@ -1,51 +1,49 @@
-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 strum::{EnumDiscriminants, IntoDiscriminant};
-use tracing::{error, info};
-
 use crate::{
     crypto::{
         KeyCell, derive_key,
         encryption::v1::{self, Nonce},
         integrity::v1::HmacSha256,
     },
-    safe_cell::SafeCell,
-};
-use crate::{
     db::{
         self,
         models::{self, RootKeyHistory},
         schema::{self},
     },
-    safe_cell::SafeCellHandle as _,
 };
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 
-#[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,
-    },
+use chrono::Utc;
+use diesel::{
+    ExpressionMethods as _, OptionalExtension, QueryDsl, SelectableHelper,
+    dsl::{insert_into, update},
+};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use hmac::{KeyInit as _, Mac as _};
+use kameo::{Actor, Reply, actor::ActorRef, messages};
+use kameo_actors::message_bus::{MessageBus, Publish};
+use strum::{EnumDiscriminants, IntoDiscriminant};
+use tracing::{error, info};
+
+pub mod events {
+
+    #[derive(Clone, Copy)]
+    pub struct Bootstrapped;
+
+    #[derive(Clone, Copy)]
+    pub struct Unsealed;
+
+    #[derive(Clone, Copy)]
+    pub struct VaultResealed;
 }
 
 #[derive(Debug, thiserror::Error)]
 pub enum Error {
-    #[error("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,
 
@@ -65,18 +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?;
 
@@ -94,10 +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?;
@@ -111,7 +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
@@ -134,6 +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) {
@@ -186,12 +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(())
     }
@@ -224,12 +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)
@@ -238,24 +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?;
@@ -268,7 +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
@@ -283,14 +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
@@ -320,19 +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
@@ -354,13 +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);
@@ -379,36 +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},
-        safe_cell::SafeCell,
-    };
+    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
@@ -420,17 +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;
 
@@ -15,11 +14,13 @@ 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;
-            } else {
-                self.0[i] += 1;
-                break;
+            if let Some(byte) = self.0.get_mut(i) {
+                if *byte == 0xFF {
+                    *byte = 0;
+                } else {
+                    *byte += 1;
+                    break;
+                }
             }
         }
     }
@@ -45,27 +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,
-        safe_cell::{SafeCell, SafeCellHandle as _},
-    };
+    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());
@@ -77,25 +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

@@ -1,44 +1,29 @@
-use crate::actors::keyholder;
-use hmac::Hmac;
-use sha2::Sha256;
-use std::future::Future;
-use std::ops::Deref;
-use std::pin::Pin;
-
-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 _;
-
-pub mod hashing;
-pub mod verified;
-use self::hashing::Hashable;
-
 use crate::{
-    actors::keyholder::{KeyHolder, SignIntegrity, VerifyIntegrity},
+    actors::vault::{self, GetState, SignIntegrity, Vault, VerifyIntegrity},
     db::{
         self,
-        models::{IntegrityEnvelope as IntegrityEnvelopeRow, NewIntegrityEnvelope},
+        models::{IntegrityEnvelope, NewIntegrityEnvelope},
         schema::integrity_envelope,
     },
 };
+use arbiter_crypto::hashing::Hashable;
 
-pub const CURRENT_PAYLOAD_VERSION: i32 = 1;
-pub const INTEGRITY_SUBKEY_TAG: &[u8] = b"arbiter/db-integrity-key/v1";
-
-pub type HmacSha256 = Hmac<Sha256>;
-pub use self::verified::{Nested, Root, VerificationOrigin, Verified};
+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 },
@@ -57,108 +42,95 @@ pub enum Error {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[must_use]
 pub enum AttestationStatus {
     Attested,
     Unavailable,
 }
 
+pub const CURRENT_PAYLOAD_VERSION: i32 = 1;
+pub const INTEGRITY_SUBKEY_TAG: &[u8] = b"arbiter/db-integrity-key/v1";
+
+pub type HmacSha256 = Hmac<Sha256>;
+
 pub trait Integrable: Hashable {
     const KIND: &'static str;
     const VERSION: i32 = 1;
 }
 
-impl<T: Integrable> Integrable for &T {
-    const KIND: &'static str = T::KIND;
-    const VERSION: i32 = T::VERSION;
+fn payload_hash(payload: &impl Hashable) -> [u8; 32] {
+    let mut hasher = Sha256::new();
+    payload.hash(&mut hasher);
+    hasher.finalize().into()
 }
 
-#[derive(Debug, Clone)]
-pub struct EntityId(Vec<u8>);
+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);
+}
 
-impl Deref for EntityId {
-    type Target = [u8];
+fn build_mac_input(
+    entity_kind: &str,
+    entity_id: &[u8],
+    payload_version: i32,
+    payload_hash: &[u8; 32],
+) -> Vec<u8> {
+    let mut out = Vec::with_capacity(8 + entity_kind.len() + entity_id.len() + 32);
+    push_len_prefixed(&mut out, entity_kind.as_bytes());
+    push_len_prefixed(&mut out, entity_id);
+    out.extend_from_slice(&payload_version.to_be_bytes());
+    out.extend_from_slice(payload_hash);
+    out
+}
 
-    fn deref(&self) -> &Self::Target {
-        &self.0
+pub trait IntoId {
+    fn into_id(self) -> Vec<u8>;
+}
+
+impl IntoId for i32 {
+    fn into_id(self) -> Vec<u8> {
+        self.to_be_bytes().to_vec()
     }
 }
 
-impl From<i32> for EntityId {
-    fn from(value: i32) -> Self {
-        Self(value.to_be_bytes().to_vec())
+impl IntoId for &'_ [u8] {
+    fn into_id(self) -> Vec<u8> {
+        self.to_vec()
     }
 }
 
-impl From<&'_ [u8]> for EntityId {
-    fn from(bytes: &'_ [u8]) -> Self {
-        Self(bytes.to_vec())
-    }
-}
-
-pub async fn lookup_verified<E, Id, C, F, Fut>(
-    conn: &mut C,
-    keyholder: &ActorRef<KeyHolder>,
-    entity_id: Id,
-    load: F,
-) -> Result<Verified<Entity<E, Id>, Nested<E>>, Error>
-where
-    C: AsyncConnection<Backend = Sqlite>,
-    E: Integrable,
-    Id: Into<EntityId> + Clone,
-    F: FnOnce(&mut C) -> Fut,
-    Fut: Future<Output = Result<E, db::DatabaseError>>,
-{
-    let entity = load(conn).await?;
-    verify_entity(conn, keyholder, entity, entity_id).await
-}
-
-pub async fn lookup_verified_from_query<E, Id, C, F>(
-    conn: &mut C,
-    keyholder: &ActorRef<KeyHolder>,
-    load: F,
-) -> Result<Verified<Entity<E, Id>, Nested<E>>, Error>
-where
-    C: AsyncConnection<Backend = Sqlite> + Send,
-    E: Integrable,
-    Id: Into<EntityId> + Clone,
-    F: for<'a> FnOnce(
-        &'a mut C,
-    ) -> Pin<
-        Box<dyn Future<Output = Result<(Id, E), db::DatabaseError>> + Send + 'a>,
-    >,
-{
-    let (entity_id, entity) = load(conn).await?;
-    verify_entity(conn, keyholder, entity, entity_id).await
-}
-
-pub async fn sign_entity<E: Integrable, Id: Into<EntityId> + Clone>(
+pub async fn sign_entity<E: Integrable>(
     conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
     entity: &E,
-    as_entity_id: Id,
-) -> Result<Verified<Id, Nested<E>>, Error> {
-    let payload_hash = payload_hash(entity);
+    entity_id: impl IntoId,
+) -> Result<(), Error> {
+    let payload_hash = payload_hash(&entity);
 
-    let entity_id = as_entity_id.clone().into();
+    let entity_id = entity_id.into_id();
 
     let mac_input = build_mac_input(E::KIND, &entity_id, E::VERSION, &payload_hash);
 
-    let (key_version, mac) = keyholder
-        .ask(SignIntegrity { mac_input })
-        .await
-        .map_err(|err| match err {
-            kameo::error::SendError::HandlerError(inner) => Error::Keyholder(inner),
-            _ => Error::KeyholderSend,
-        })?;
+    let (key_version, mac) =
+        vault
+            .ask(SignIntegrity { mac_input })
+            .await
+            .map_err(|err| match err {
+                SendError::HandlerError(inner) => Error::Vault(inner),
+                _ => Error::VaultSend,
+            })?;
 
     insert_into(integrity_envelope::table)
         .values(NewIntegrityEnvelope {
             entity_kind: E::KIND.to_owned(),
-            entity_id: entity_id.to_vec(),
+            entity_id,
             payload_version: E::VERSION,
             key_version,
-            mac: mac.to_vec(),
+            mac: mac.clone(),
         })
         .on_conflict((
             integrity_envelope::entity_id,
@@ -174,19 +146,19 @@ pub async fn sign_entity<E: Integrable, Id: Into<EntityId> + Clone>(
         .await
         .map_err(db::DatabaseError::from)?;
 
-    Ok(Verified::<Id, Nested<E>>::new(as_entity_id))
+    Ok(())
 }
 
-pub async fn check_entity_attestation<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 Into<EntityId>,
+    entity_id: impl IntoId,
 ) -> Result<AttestationStatus, Error> {
-    let entity_id = entity_id.into();
-    let envelope: IntegrityEnvelopeRow = integrity_envelope::table
+    let entity_id = entity_id.into_id();
+    let envelope: IntegrityEnvelope = integrity_envelope::table
         .filter(integrity_envelope::entity_kind.eq(E::KIND))
-        .filter(integrity_envelope::entity_id.eq(&*entity_id))
+        .filter(integrity_envelope::entity_id.eq(&entity_id))
         .first(conn)
         .await
         .map_err(|err| match err {
@@ -204,10 +176,10 @@ pub async fn check_entity_attestation<E: Integrable>(
         });
     }
 
-    let payload_hash = payload_hash(entity);
+    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,
@@ -220,100 +192,143 @@ pub async fn check_entity_attestation<E: Integrable>(
         Ok(false) => Err(Error::MacMismatch {
             entity_kind: E::KIND,
         }),
-        Err(SendError::HandlerError(keyholder::Error::NotBootstrapped)) => {
-            Ok(AttestationStatus::Unavailable)
-        }
-        Err(_) => Err(Error::KeyholderSend),
+        Err(SendError::HandlerError(vault::Error::Sealed)) => Ok(AttestationStatus::Unavailable),
+        Err(_) => Err(Error::VaultSend),
     }
 }
 
-#[derive(Debug, Clone, crate::VerifiedFields!)]
-#[repr(C)]
-pub struct Entity<E, Id> {
-    pub entity: E,
-    pub entity_id: Id,
-}
-
-impl<E, Id> Deref for Entity<E, Id> {
-    type Target = E;
-
-    fn deref(&self) -> &Self::Target {
-        &self.entity
-    }
-}
-
-pub async fn verify_entity<E: Integrable, Id: Into<EntityId> + Clone>(
-    conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    keyholder: &ActorRef<KeyHolder>,
-    entity: E,
-    entity_id: Id,
-) -> Result<Verified<Entity<E, Id>, Nested<E>>, Error> {
-    match check_entity_attestation(conn, keyholder, &entity, entity_id.clone()).await? {
-        AttestationStatus::Attested => Ok(Verified::<Entity<E, Id>, Nested<E>>::new(Entity {
-            entity,
-            entity_id,
-        })),
-        AttestationStatus::Unavailable => Err(Error::Keyholder(keyholder::Error::NotBootstrapped)),
-    }
-}
-
-pub async fn verify_entity_ref<'e, E: Integrable, Id: Into<EntityId> + Clone>(
-    conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    keyholder: &ActorRef<KeyHolder>,
-    entity: &'e E,
-    entity_id: Id,
-) -> Result<Verified<Entity<&'e E, Id>, Nested<E>>, Error> {
-    match check_entity_attestation(conn, keyholder, entity, entity_id.clone()).await? {
-        AttestationStatus::Attested => Ok(Verified::<Entity<&'e E, Id>, Nested<E>>::new(Entity {
-            entity,
-            entity_id,
-        })),
-        AttestationStatus::Unavailable => Err(Error::Keyholder(keyholder::Error::NotBootstrapped)),
-    }
-}
-
-pub async fn delete_envelope<E: Integrable>(
-    conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    entity_id: impl Into<EntityId>,
-) -> Result<usize, Error> {
-    let entity_id = entity_id.into();
-
-    let affected = diesel::delete(
-        integrity_envelope::table
-            .filter(integrity_envelope::entity_kind.eq(E::KIND))
-            .filter(integrity_envelope::entity_id.eq(&*entity_id)),
-    )
-    .execute(conn)
-    .await
-    .map_err(db::DatabaseError::from)?;
-
-    Ok(affected)
-}
-
-fn payload_hash(payload: &impl Hashable) -> [u8; 32] {
-    let mut hasher = Sha256::new();
-    payload.hash(&mut hasher);
-    hasher.finalize().into()
-}
-
-fn build_mac_input(
-    entity_kind: &str,
-    entity_id: &[u8],
-    payload_version: i32,
-    payload_hash: &[u8; 32],
-) -> Vec<u8> {
-    let mut out = Vec::with_capacity(8 + entity_kind.len() + entity_id.len() + 32);
-    push_len_prefixed(&mut out, entity_kind.as_bytes());
-    push_len_prefixed(&mut out, entity_id);
-    out.extend_from_slice(&payload_version.to_be_bytes());
-    out.extend_from_slice(payload_hash);
-    out
-}
-
-fn push_len_prefixed(out: &mut Vec<u8>, bytes: &[u8]) {
-    out.extend_from_slice(&(bytes.len() as u32).to_be_bytes());
-    out.extend_from_slice(bytes);
+pub async fn is_signing_available(vault: &ActorRef<Vault>) -> Result<bool, Error> {
+    let state = vault.ask(GetState).await.map_err(|_| Error::VaultSend)?;
+    Ok(matches!(state, vault::VaultState::Unsealed))
 }
 
 #[cfg(test)]
-mod tests;
+mod tests {
+    use diesel::{ExpressionMethods as _, QueryDsl};
+    use diesel_async::RunQueryDsl;
+    use kameo::{actor::ActorRef, prelude::Spawn};
+
+    use crate::{
+        actors::{
+            GlobalActors,
+            vault::{Bootstrap, Vault},
+        },
+        db::{self, schema},
+    };
+    use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+
+    use super::{Error, Integrable, sign_entity, verify_entity};
+    #[derive(Clone, arbiter_macros::Hashable)]
+    struct DummyEntity {
+        payload_version: i32,
+        payload: Vec<u8>,
+    }
+    impl Integrable for DummyEntity {
+        const KIND: &'static str = "dummy_entity";
+    }
+
+    async fn bootstrapped_vault(db: &db::DatabasePool) -> ActorRef<Vault> {
+        let actor = Vault::spawn(
+            Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+                .await
+                .unwrap(),
+        );
+        actor
+            .ask(Bootstrap {
+                seal_key_raw: SafeCell::new(b"integrity-test-seal-key".to_vec()),
+            })
+            .await
+            .unwrap();
+        actor
+    }
+
+    #[tokio::test]
+    async fn sign_writes_envelope_and_verify_passes() {
+        const ENTITY_ID: &[u8] = b"entity-id-7";
+
+        let db = db::create_test_pool().await;
+        let vault = bootstrapped_vault(&db).await;
+        let mut conn = db.get().await.unwrap();
+
+        let entity = DummyEntity {
+            payload_version: 1,
+            payload: b"payload-v1".to_vec(),
+        };
+
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap();
+
+        let count: i64 = schema::integrity_envelope::table
+            .filter(schema::integrity_envelope::entity_kind.eq("dummy_entity"))
+            .filter(schema::integrity_envelope::entity_id.eq(ENTITY_ID))
+            .count()
+            .get_result(&mut conn)
+            .await
+            .unwrap();
+
+        assert_eq!(count, 1, "envelope row must be created exactly once");
+        verify_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap();
+    }
+
+    #[tokio::test]
+    async fn tampered_mac_fails_verification() {
+        const ENTITY_ID: &[u8] = b"entity-id-11";
+
+        let db = db::create_test_pool().await;
+        let vault = bootstrapped_vault(&db).await;
+        let mut conn = db.get().await.unwrap();
+
+        let entity = DummyEntity {
+            payload_version: 1,
+            payload: b"payload-v1".to_vec(),
+        };
+
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap();
+
+        diesel::update(schema::integrity_envelope::table)
+            .filter(schema::integrity_envelope::entity_kind.eq("dummy_entity"))
+            .filter(schema::integrity_envelope::entity_id.eq(ENTITY_ID))
+            .set(schema::integrity_envelope::mac.eq(vec![0u8; 32]))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+
+        let err = verify_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap_err();
+        assert!(matches!(err, Error::MacMismatch { .. }));
+    }
+
+    #[tokio::test]
+    async fn changed_payload_fails_verification() {
+        const ENTITY_ID: &[u8] = b"entity-id-21";
+
+        let db = db::create_test_pool().await;
+        let vault = bootstrapped_vault(&db).await;
+        let mut conn = db.get().await.unwrap();
+
+        let entity = DummyEntity {
+            payload_version: 1,
+            payload: b"payload-v1".to_vec(),
+        };
+
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap();
+
+        let tampered = DummyEntity {
+            payload: b"payload-v1-but-tampered".to_vec(),
+            ..entity
+        };
+
+        let err = verify_entity(&mut conn, &vault, &tampered, ENTITY_ID)
+            .await
+            .unwrap_err();
+        assert!(matches!(err, Error::MacMismatch { .. }));
+    }
+}

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

@@ -1,298 +0,0 @@
-use diesel::{ExpressionMethods as _, QueryDsl};
-use diesel_async::RunQueryDsl;
-use kameo::{actor::ActorRef, prelude::Spawn};
-use sha2::Digest;
-
-use crate::{
-    actors::keyholder::{Bootstrap, KeyHolder},
-    db::{self, schema},
-    safe_cell::{SafeCell, SafeCellHandle as _},
-};
-
-use super::hashing::Hashable;
-use super::{
-    Error, Integrable, check_entity_attestation, lookup_verified, lookup_verified_from_query,
-    sign_entity, verify_entity,
-};
-
-#[derive(Clone, Debug)]
-struct DummyEntity {
-    payload_version: i32,
-    payload: Vec<u8>,
-}
-
-impl Hashable for DummyEntity {
-    fn hash<H: Digest>(&self, hasher: &mut H) {
-        self.payload_version.hash(hasher);
-        self.payload.hash(hasher);
-    }
-}
-impl Integrable for DummyEntity {
-    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());
-    actor
-        .ask(Bootstrap {
-            seal_key_raw: SafeCell::new(b"integrity-test-seal-key".to_vec()),
-        })
-        .await
-        .unwrap();
-    actor
-}
-
-#[tokio::test]
-async fn sign_writes_envelope_and_verify_passes() {
-    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 entity = DummyEntity {
-        payload_version: 1,
-        payload: b"payload-v1".to_vec(),
-    };
-
-    sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
-        .await
-        .unwrap()
-        .drop_verification_provenance();
-
-    let count: i64 = schema::integrity_envelope::table
-        .filter(schema::integrity_envelope::entity_kind.eq("dummy_entity"))
-        .filter(schema::integrity_envelope::entity_id.eq(ENTITY_ID))
-        .count()
-        .get_result(&mut conn)
-        .await
-        .unwrap();
-
-    assert_eq!(count, 1, "envelope row must be created exactly once");
-    let _ = check_entity_attestation(&mut conn, &keyholder, &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 entity = DummyEntity {
-        payload_version: 1,
-        payload: b"payload-v1".to_vec(),
-    };
-
-    sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
-        .await
-        .unwrap()
-        .drop_verification_provenance();
-
-    diesel::update(schema::integrity_envelope::table)
-        .filter(schema::integrity_envelope::entity_kind.eq("dummy_entity"))
-        .filter(schema::integrity_envelope::entity_id.eq(ENTITY_ID))
-        .set(schema::integrity_envelope::mac.eq(vec![0u8; 32]))
-        .execute(&mut conn)
-        .await
-        .unwrap();
-
-    let err = check_entity_attestation(&mut conn, &keyholder, &entity, ENTITY_ID)
-        .await
-        .unwrap_err();
-    assert!(matches!(err, Error::MacMismatch { .. }));
-}
-
-#[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 entity = DummyEntity {
-        payload_version: 1,
-        payload: b"payload-v1".to_vec(),
-    };
-
-    sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
-        .await
-        .unwrap()
-        .drop_verification_provenance();
-
-    let tampered = DummyEntity {
-        payload: b"payload-v1-but-tampered".to_vec(),
-        ..entity
-    };
-
-    let err = check_entity_attestation(&mut conn, &keyholder, &tampered, ENTITY_ID)
-        .await
-        .unwrap_err();
-    assert!(matches!(err, Error::MacMismatch { .. }));
-}
-
-#[tokio::test]
-async fn strict_verify_fails_closed_while_sealed() {
-    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-41";
-
-    let entity = DummyEntity {
-        payload_version: 1,
-        payload: b"payload-v1".to_vec(),
-    };
-
-    sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
-        .await
-        .unwrap()
-        .drop_verification_provenance();
-    drop(keyholder);
-
-    let sealed_keyholder = KeyHolder::spawn(KeyHolder::new(db.clone()).await.unwrap());
-
-    let err = verify_entity(&mut conn, &sealed_keyholder, &entity, ENTITY_ID)
-        .await
-        .unwrap_err();
-    assert!(matches!(
-        err,
-        Error::Keyholder(crate::actors::keyholder::Error::NotBootstrapped)
-    ));
-
-    let err = lookup_verified(&mut conn, &sealed_keyholder, ENTITY_ID, |_| async {
-        Ok::<_, db::DatabaseError>(DummyEntity {
-            payload_version: 1,
-            payload: b"payload-v1".to_vec(),
-        })
-    })
-    .await
-    .unwrap_err();
-    assert!(matches!(
-        err,
-        Error::Keyholder(crate::actors::keyholder::Error::NotBootstrapped)
-    ));
-}
-
-#[tokio::test]
-async fn lookup_verified_supports_loaded_aggregate() {
-    let db = db::create_test_pool().await;
-    let keyholder = bootstrapped_keyholder(&db).await;
-    let mut conn = db.get().await.unwrap();
-
-    const ENTITY_ID: i32 = 77;
-
-    let entity = DummyEntity {
-        payload_version: 1,
-        payload: b"payload-v1".to_vec(),
-    };
-
-    sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
-        .await
-        .unwrap()
-        .drop_verification_provenance();
-
-    let verified = lookup_verified(&mut conn, &keyholder, ENTITY_ID, |_| async {
-        Ok::<_, db::DatabaseError>(DummyEntity {
-            payload_version: 1,
-            payload: b"payload-v1".to_vec(),
-        })
-    })
-    .await
-    .unwrap();
-
-    assert_eq!(verified.entity.payload, b"payload-v1".to_vec());
-}
-
-#[tokio::test]
-async fn extension_trait_lookup_verified_required_works() {
-    let db = db::create_test_pool().await;
-    let keyholder = bootstrapped_keyholder(&db).await;
-    let mut conn = db.get().await.unwrap();
-
-    const ENTITY_ID: i32 = 79;
-
-    let entity = DummyEntity {
-        payload_version: 1,
-        payload: b"payload-v1".to_vec(),
-    };
-
-    sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
-        .await
-        .unwrap()
-        .drop_verification_provenance();
-
-    let verified = lookup_verified(&mut conn, &keyholder, ENTITY_ID, |_| {
-        Box::pin(async {
-            Ok::<_, db::DatabaseError>(DummyEntity {
-                payload_version: 1,
-                payload: b"payload-v1".to_vec(),
-            })
-        })
-    })
-    .await
-    .unwrap();
-
-    assert_eq!(verified.entity.payload, b"payload-v1".to_vec());
-}
-
-#[tokio::test]
-async fn lookup_verified_from_query_helpers_work() {
-    let db = db::create_test_pool().await;
-    let keyholder = bootstrapped_keyholder(&db).await;
-    let mut conn = db.get().await.unwrap();
-
-    const ENTITY_ID: i32 = 80;
-
-    let entity = DummyEntity {
-        payload_version: 1,
-        payload: b"payload-v1".to_vec(),
-    };
-
-    sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
-        .await
-        .unwrap()
-        .drop_verification_provenance();
-
-    let verified = lookup_verified_from_query(&mut conn, &keyholder, |_| {
-        Box::pin(async {
-            Ok::<_, db::DatabaseError>((
-                ENTITY_ID,
-                DummyEntity {
-                    payload_version: 1,
-                    payload: b"payload-v1".to_vec(),
-                },
-            ))
-        })
-    })
-    .await
-    .unwrap();
-
-    assert_eq!(verified.entity.payload, b"payload-v1".to_vec());
-
-    drop(keyholder);
-    let sealed_keyholder = KeyHolder::spawn(KeyHolder::new(db.clone()).await.unwrap());
-
-    let err = lookup_verified_from_query(&mut conn, &sealed_keyholder, |_| {
-        Box::pin(async {
-            Ok::<_, db::DatabaseError>((
-                ENTITY_ID,
-                DummyEntity {
-                    payload_version: 1,
-                    payload: b"payload-v1".to_vec(),
-                },
-            ))
-        })
-    })
-    .await
-    .unwrap_err();
-
-    assert!(matches!(
-        err,
-        Error::Keyholder(crate::actors::keyholder::Error::NotBootstrapped)
-    ));
-}

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

@@ -1,593 +0,0 @@
-use std::ops::Deref;
-
-use super::Integrable;
-
-mod private {
-    pub trait Sealed {}
-}
-
-/// Marker trait for type-level verification provenance.
-///
-/// This trait is intentionally sealed so external code cannot invent arbitrary
-/// provenance tags and bypass the intended type-level guarantees.
-pub trait VerificationOrigin: private::Sealed {
-    type Origin: VerificationOrigin;
-}
-
-/// Root provenance marker for values directly produced by integrity APIs.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Default)]
-pub struct Root;
-
-/// Nested provenance marker carrying the source integrable type and previous
-/// provenance marker in the chain.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct Nested<From, P: VerificationOrigin = Root>(core::marker::PhantomData<(From, P)>);
-
-impl private::Sealed for Root {}
-impl VerificationOrigin for Root {
-    type Origin = Self;
-}
-
-impl<T, P: VerificationOrigin> private::Sealed for Nested<T, P> {}
-impl<T, P: VerificationOrigin> VerificationOrigin for Nested<T, P> {
-    type Origin = P;
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[repr(transparent)]
-#[must_use = "Verified<T> is a proof-bearing wrapper; use self.drop_verification_provenance() to explicitly discard integrity provenance when needed"]
-pub struct Verified<T, O: VerificationOrigin = Root> {
-    inner: T,
-    origin: core::marker::PhantomData<O>,
-}
-
-impl<T, O: VerificationOrigin> AsRef<Verified<T, O>> for Verified<&T, O> {
-    fn as_ref(&self) -> &Verified<T, O> {
-        // SAFETY: `Verified<T>` is `#[repr(transparent)]` over `T`, so `&T`
-        // and `&Verified<T>` have identical layout.
-        unsafe { reinterpret_layout_ref::<T, Verified<T, O>>(self.inner) }
-    }
-}
-
-impl<T, U: Integrable, O: VerificationOrigin> Deref for Verified<T, Nested<U, O>> {
-    type Target = Verified<T, O::Origin>;
-
-    fn deref(&self) -> &Self::Target {
-        // SAFETY: `Verified<T, Nested<U, O>>` is `#[repr(transparent)]` over `T`, so `&Verified<T, Nested<U, O>>`
-        // and `&Nested<U, O>` have identical layout.
-        unsafe { reinterpret_layout_ref::<Self, Verified<T, O::Origin>>(self) }
-    }
-}
-impl<T> Deref for Verified<T, Root> {
-    type Target = T;
-
-    fn deref(&self) -> &Self::Target {
-        &self.inner
-    }
-}
-
-impl<T, O: VerificationOrigin> Verified<T, O> {
-    /// Unwraps the verified value, discarding the integrity provenance.
-    ///
-    /// The name is intentionally verbose — call sites where provenance is
-    /// dropped should be easy to find and audit.
-    pub fn drop_verification_provenance(self) -> T {
-        self.inner
-    }
-
-    /// Downgrades the origin provenance to any lower nestedness level,
-    /// e.g. `Verified<T, Nested<Other>>` to `Verified<T, Root>`.
-    pub fn unqualify_origin<Target: VerificationOrigin>(self) -> Verified<T, Target>
-    where
-        O: VerificationOrigin<Origin = Target>,
-    {
-        Verified {
-            inner: self.inner,
-            origin: core::marker::PhantomData,
-        }
-    }
-
-    /// Constructs a `Verified<T>` by wrapping a `T`.
-    pub(super) fn new(value: T) -> Self {
-        Self {
-            inner: value,
-            origin: core::marker::PhantomData,
-        }
-    }
-
-    /// Constructs a `Verified<T>` from a raw value without performing any
-    /// integrity check. Only available in test builds; use the integrity
-    /// module's functions to obtain a `Verified<T>` in production code.
-    #[cfg(test)]
-    pub(crate) fn new_unchecked(value: T) -> Self {
-        Self {
-            inner: value,
-            origin: core::marker::PhantomData,
-        }
-    }
-
-    /// Reinterprets `&T` as `&Verified<T>`.
-    #[allow(dead_code)]
-    pub(super) fn from_ref(from: &T) -> &Self {
-        // SAFETY: `Self` is `#[repr(transparent)]` over `T`.
-        unsafe { reinterpret_layout_ref::<T, Self>(from) }
-    }
-}
-
-/// Bit-copies `value: From` into a `To`, suppressing the source destructor so
-/// the destination owns the bytes.
-///
-/// # Safety
-///
-/// The caller must guarantee that `From` and `To` have identical in-memory
-/// layout — the raw bytes that encode a valid `From` must also encode a valid
-/// `To`.
-///
-/// A `union` is used instead of [`std::mem::transmute`] because `transmute`
-/// rejects generic source/destination types at the call site even when their
-/// sizes are provably equal at monomorphization time.
-#[allow(dead_code)]
-#[inline]
-pub const unsafe fn reinterpret_layout<From, To>(value: From) -> To {
-    const {
-        assert!(
-            ::std::mem::size_of::<From>() == ::std::mem::size_of::<To>(),
-            "reinterpret_layout: source and destination must have identical size"
-        );
-        assert!(
-            ::std::mem::align_of::<From>() == ::std::mem::align_of::<To>(),
-            "reinterpret_layout: source and destination must have identical alignment"
-        );
-    }
-    union Reinterpret<A, B> {
-        from: ::std::mem::ManuallyDrop<A>,
-        to: ::std::mem::ManuallyDrop<B>,
-    }
-    // SAFETY: caller guarantees layout equivalence (see fn docs). The union
-    // write-read copies the raw bytes of `value` into a `To` slot, and
-    // `ManuallyDrop` on the source side suppresses its destructor so the
-    // destination owns the bytes unambiguously — no double-drop is possible.
-    unsafe {
-        ::std::mem::ManuallyDrop::into_inner(
-            Reinterpret {
-                from: ::std::mem::ManuallyDrop::new(value),
-            }
-            .to,
-        )
-    }
-}
-
-/// Reinterprets `&From` as `&To` via a layout-preserving pointer cast.
-///
-/// # Safety
-///
-/// Same invariants as [`reinterpret_layout`].
-#[inline]
-pub const unsafe fn reinterpret_layout_ref<From, To>(value: &From) -> &To {
-    const {
-        assert!(
-            ::std::mem::size_of::<From>() == ::std::mem::size_of::<To>(),
-            "reinterpret_layout_ref: source and destination must have identical size"
-        );
-        assert!(
-            ::std::mem::align_of::<From>() == ::std::mem::align_of::<To>(),
-            "reinterpret_layout_ref: source and destination must have identical alignment"
-        );
-    }
-    // SAFETY: caller guarantees layout equivalence (see fn docs). A reference
-    // cast between identically-laid-out types produces a reference with the
-    // same address and lifetime, which is sound.
-    unsafe { &*(value as *const From as *const To) }
-}
-
-/// Implemented on `Verified<T>` by [`VerifiedFields!`], exposing the field-wise counterpart.
-///
-/// ## Disclaimer
-/// Do not implement this trait manually. It is intended to be implemented only
-/// by the `VerifiedFields!` macro, which generates the necessary layout
-/// guarantees for sound pointer casts.
-///
-/// ## Soundness
-/// When [`verify_entity`][crate::crypto::integrity::verify_entity] attests an
-/// entity, it returns `Verified<T>` — an aggregate proof over the whole value.
-/// This trait converts that wrapper into `Counterpart` (e.g.
-/// `VerifiedMyStruct`), where every field is individually wrapped in
-/// [`Verified`], allowing verified data to flow into functions that require
-/// `Verified<FieldType>` without re-verifying.
-///
-/// ## Safety
-/// The conversion is a zero-cost reinterpretation — no copying (beyond a
-/// bitwise move in the owned variant) or HMAC work occurs. Soundness rests on
-/// identical memory layout between `Verified<T>` and `Counterpart`:
-///
-/// - `T` carries `#[repr(C)]` (enforced by `@require_repr` in the macro).
-/// - `T` does **not** carry `packed` (enforced by `@reject_packed`).
-/// - `Counterpart` also carries `#[repr(C)]`, with the same fields in the same
-///   order.
-/// - Each `Verified<F>` field is `#[repr(transparent)]` over `F`, so its size
-///   and alignment match `F` exactly.
-/// - `Verified<T>` itself is `#[repr(transparent)]` over `T`.
-///
-/// As an additional machine-checked guard, [`reinterpret_layout`] and
-/// [`reinterpret_layout_ref`] assert size/align equality of the two types at
-/// monomorphization time.
-///
-/// The trait is implemented directly on `Verified<T>` (not on `T`), so no
-/// `Deref`-coercion or auto-ref stripping is needed at call sites — the impl
-/// is unambiguous.
-pub trait VerifiedFieldsAccessor {
-    /// The field-wise verified counterpart, e.g. `VerifiedMyStruct`.
-    type Counterpart;
-
-    /// Reinterprets `&self` as `&Counterpart` via a layout-preserving pointer cast.
-    ///
-    /// No data is copied and no re-verification occurs. The returned reference
-    /// borrows from `self` and has the same lifetime.
-    fn inherit_ref(&self) -> &Self::Counterpart;
-
-    /// Consumes `self` and returns `Counterpart` via a layout-preserving
-    /// bitwise move.
-    ///
-    /// The original `Verified<T>` is moved without running its destructor
-    /// (there is none — `Verified` is a transparent wrapper with no heap
-    /// allocation), and the returned counterpart owns the original bytes. No
-    /// re-verification occurs.
-    fn inherit(self) -> Self::Counterpart;
-}
-
-// todo! rewrite macro_rules to derive crate
-#[macro_export]
-macro_rules! VerifiedFields {
-    // --- Entry point (no source generics) ---
-    (
-        $(#$attr:tt)*
-        $vis:vis struct $name:ident
-        {
-            $(
-                $field_vis:vis $field_name:ident : $field_ty:ty
-            ),* $(,)?
-        }
-    ) => {
-        // Attribute-list checks run in isolation — they only receive the attrs,
-        // not the struct body.
-        $crate::VerifiedFields!(@require_repr [$(#$attr)*]);
-        $crate::VerifiedFields!(@reject_packed [$(#$attr)*]);
-
-        paste::paste! {
-            #[doc = concat!(
-                "Field-wise verified counterpart of [`", stringify!($name), "`]."
-            )]
-            //
-            // `#[repr(C)]` is required for the pointer casts in `inherit_ref`
-            // and `inherit` to be sound. Both the source struct (enforced by
-            // `@require_repr`) and this counterpart carry `#[repr(C)]`, which
-            // guarantees matching field offsets. Combined with each
-            // `Verified<F>` being `#[repr(transparent)]` over `F`, the two
-            // structs have identical memory layout.
-            //
-            // `#[repr(transparent)]` is not usable here because it only permits
-            // a single non-ZST field; multi-field structs would fail to compile.
-            #[repr(C)]
-            $vis struct [<Verified $name>]<P: $crate::crypto::integrity::v1::verified::VerificationOrigin>
-            {
-                $(
-                    $field_vis $field_name : $crate::crypto::integrity::Verified<$field_ty, P>
-                ),*
-            }
-
-            impl<P: $crate::crypto::integrity::v1::verified::VerificationOrigin>
-                $crate::crypto::integrity::v1::verified::VerifiedFieldsAccessor
-                for $crate::crypto::integrity::Verified<$name, P>
-            {
-                type Counterpart = [<Verified $name>]<P>;
-
-                fn inherit_ref(&self) -> &Self::Counterpart {
-                    // SAFETY: `Self` is `Verified<T>` (transparent over
-                    // `T #[repr(C)]`) and `Self::Counterpart` is `#[repr(C)]`
-                    // with the same fields in the same order, each wrapped in
-                    // a `#[repr(transparent)]` `Verified<F>`. The two types
-                    // therefore have identical memory layout, which
-                    // `reinterpret_layout_ref` re-checks as size/align
-                    // equality at monomorphization.
-                    unsafe {
-                        $crate::crypto::integrity::v1::verified::reinterpret_layout_ref::<
-                            Self,
-                            Self::Counterpart,
-                        >(self)
-                    }
-                }
-
-                fn inherit(self) -> Self::Counterpart {
-                    // SAFETY: identical layout — see `inherit_ref`. The owned
-                    // helper additionally suppresses the source destructor so
-                    // the returned counterpart owns the original bytes (no
-                    // double-drop is possible).
-                    unsafe {
-                        $crate::crypto::integrity::v1::verified::reinterpret_layout::<
-                            Self,
-                            Self::Counterpart,
-                        >(self)
-                    }
-                }
-            }
-        }
-    };
-
-    // --- Entry point (source has generics) ---
-    (
-        $(#$attr:tt)*
-        $vis:vis struct $name:ident <$($gen:tt),*>
-        {
-            $(
-                $field_vis:vis $field_name:ident : $field_ty:ty
-            ),* $(,)?
-        }
-    ) => {
-        // Attribute-list checks run in isolation — they only receive the attrs,
-        // not the struct body.
-        $crate::VerifiedFields!(@require_repr [$(#$attr)*]);
-        $crate::VerifiedFields!(@reject_packed [$(#$attr)*]);
-
-        paste::paste! {
-            #[doc = concat!(
-                "Field-wise verified counterpart of [`", stringify!($name), "`]."
-            )]
-            //
-            // `#[repr(C)]` is required for the pointer casts in `inherit_ref`
-            // and `inherit` to be sound. Both the source struct (enforced by
-            // `@require_repr`) and this counterpart carry `#[repr(C)]`, which
-            // guarantees matching field offsets. Combined with each
-            // `Verified<F>` being `#[repr(transparent)]` over `F`, the two
-            // structs have identical memory layout.
-            //
-            // `#[repr(transparent)]` is not usable here because it only permits
-            // a single non-ZST field; multi-field structs would fail to compile.
-            #[repr(C)]
-            $vis struct [<Verified $name>]<$($gen),*, P: $crate::crypto::integrity::v1::verified::VerificationOrigin>
-            {
-                $(
-                    $field_vis $field_name : $crate::crypto::integrity::Verified<$field_ty, P>
-                ),*
-            }
-
-            impl<$($gen),*, P: $crate::crypto::integrity::v1::verified::VerificationOrigin>
-                $crate::crypto::integrity::v1::verified::VerifiedFieldsAccessor
-                for $crate::crypto::integrity::Verified<$name<$($gen),*>, P>
-            {
-                type Counterpart = [<Verified $name>]<$($gen),*, P>;
-
-                fn inherit_ref(&self) -> &Self::Counterpart {
-                    // SAFETY: `Self` is `Verified<T>` (transparent over
-                    // `T #[repr(C)]`) and `Self::Counterpart` is `#[repr(C)]`
-                    // with the same fields in the same order, each wrapped in
-                    // a `#[repr(transparent)]` `Verified<F>`. The two types
-                    // therefore have identical memory layout, which
-                    // `reinterpret_layout_ref` re-checks as size/align
-                    // equality at monomorphization.
-                    unsafe {
-                        $crate::crypto::integrity::v1::verified::reinterpret_layout_ref::<
-                            Self,
-                            Self::Counterpart,
-                        >(self)
-                    }
-                }
-
-                fn inherit(self) -> Self::Counterpart {
-                    // SAFETY: identical layout — see `inherit_ref`. The owned
-                    // helper additionally suppresses the source destructor so
-                    // the returned counterpart owns the original bytes (no
-                    // double-drop is possible).
-                    unsafe {
-                        $crate::crypto::integrity::v1::verified::reinterpret_layout::<
-                            Self,
-                            Self::Counterpart,
-                        >(self)
-                    }
-                }
-            }
-        }
-    };
-
-    // --- @require_repr: ensure `#[repr(C)]` appears in the attribute list ---
-    (@require_repr [#[repr(C)] $($rest:tt)*]) => {};
-    (@require_repr [#$other:tt $($rest:tt)*]) => {
-        $crate::VerifiedFields!(@require_repr [$($rest)*]);
-    };
-    (@require_repr []) => {
-        ::std::compile_error!(
-            "VerifiedFields requires `#[repr(C)]` on the struct to guarantee field layout"
-        );
-    };
-
-    // --- @reject_packed: walk attrs and reject any `#[repr(..., packed, ...)]`.
-    //
-    // Without this, a packed struct would still fail at monomorphization via
-    // the const assertions inside the `reinterpret_layout*` helpers, but the
-    // diagnostic would be much harder to read. `align(N)` is *not* rejected
-    // here because const assertions catch alignment mismatches cleanly, and
-    // forbidding it would be unnecessarily restrictive.
-    (@reject_packed [#[repr($($inner:tt)*)] $($rest:tt)*]) => {
-        $crate::VerifiedFields!(@reject_packed_inner [$($inner)*]);
-        $crate::VerifiedFields!(@reject_packed [$($rest)*]);
-    };
-    (@reject_packed [#$other:tt $($rest:tt)*]) => {
-        $crate::VerifiedFields!(@reject_packed [$($rest)*]);
-    };
-    (@reject_packed []) => {};
-
-    (@reject_packed_inner [packed $($rest:tt)*]) => {
-        ::std::compile_error!(
-            "VerifiedFields does not support packed layouts; the generated \
-             counterpart would not share layout with the source struct"
-        );
-    };
-    (@reject_packed_inner [$first:tt $($rest:tt)*]) => {
-        $crate::VerifiedFields!(@reject_packed_inner [$($rest)*]);
-    };
-    (@reject_packed_inner []) => {};
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[derive(VerifiedFields!)]
-    #[repr(C)]
-    #[derive(Default, Clone)]
-    pub struct MyStruct<T> {
-        pub field1: String,
-        pub field2: T,
-    }
-
-    fn verify<T>(t: T) -> Verified<T> {
-        Verified {
-            inner: t,
-            origin: core::marker::PhantomData,
-        }
-    }
-
-    // --- inherit_ref ---
-
-    // Verifies that `inherit_ref` returns a reference to the same memory
-    // address, confirming that no copy is made and the cast is purely a
-    // reinterpretation.
-    #[test]
-    fn inherit_ref_is_same_address() {
-        let v = verify(MyStruct {
-            field1: "hello".into(),
-            field2: 42u32,
-        });
-        let fields = v.inherit_ref();
-        assert_eq!(
-            &v as *const _ as *const u8, fields as *const _ as *const u8,
-            "inherit_ref must return a pointer to the same memory, not a copy"
-        );
-    }
-
-    // Verifies that field values are correctly accessible after `inherit_ref`.
-    #[test]
-    fn inherit_ref_field_values() {
-        let v = verify(MyStruct {
-            field1: "hello".into(),
-            field2: 99u32,
-        });
-        let fields = v.inherit_ref();
-        assert_eq!(*fields.field1, "hello");
-        assert_eq!(*fields.field2, 99u32);
-    }
-
-    // Verifies that casting the counterpart back to `Verified<T>` via a raw
-    // pointer lands on the original address — confirms the round-trip is a
-    // pure reinterpretation.
-    #[test]
-    fn inherit_ref_cast_roundtrip() {
-        let v = verify(MyStruct {
-            field1: "x".into(),
-            field2: 7u32,
-        });
-        let fields: &VerifiedMyStruct<u32, Root> = v.inherit_ref();
-        let back_ptr =
-            fields as *const VerifiedMyStruct<u32, Root> as *const Verified<MyStruct<u32>>;
-        assert_eq!(
-            back_ptr as *const u8, &v as *const _ as *const u8,
-            "cast of counterpart must point back to the same Verified<T>"
-        );
-    }
-
-    // ZST fields must still produce a counterpart with identical layout — the
-    // const asserts in `reinterpret_layout_ref` guard this at monomorphization.
-    #[test]
-    fn inherit_ref_with_zst_field() {
-        #[derive(VerifiedFields!)]
-        #[repr(C)]
-        struct WithZst {
-            pub unit: (),
-            pub val: u64,
-        }
-
-        let v = Verified::<WithZst>::new_unchecked(WithZst { unit: (), val: 777 });
-        let fields = v.inherit_ref();
-        assert_eq!(*fields.val, 777);
-        assert_eq!(*fields.unit, ());
-    }
-
-    // --- inherit ---
-
-    // Verifies that `inherit` preserves field values in the owned counterpart.
-    #[test]
-    fn inherit_field_values() {
-        let v = verify(MyStruct {
-            field1: "world".into(),
-            field2: 1234u64,
-        });
-        let VerifiedMyStruct { field1, field2 } = v.inherit();
-        assert_eq!(*field1, "world");
-        assert_eq!(*field2, 1234u64);
-    }
-
-    // Verifies that `inherit` does not double-drop the inner value.
-    // If `ManuallyDrop` handling is wrong, running under Miri or with a drop
-    // counter catches a double-free.
-    #[test]
-    fn inherit_no_double_drop() {
-        use std::sync::atomic::{AtomicUsize, Ordering};
-
-        static DROP_COUNT: AtomicUsize = AtomicUsize::new(0);
-
-        struct DropCounter;
-        impl Drop for DropCounter {
-            fn drop(&mut self) {
-                DROP_COUNT.fetch_add(1, Ordering::Relaxed);
-            }
-        }
-
-        #[derive(VerifiedFields!)]
-        #[repr(C)]
-        struct WithDrop {
-            pub val: DropCounter,
-        }
-
-        DROP_COUNT.store(0, Ordering::Relaxed);
-        {
-            let v = Verified::<WithDrop>::new_unchecked(WithDrop { val: DropCounter });
-            let _ = v.inherit();
-        }
-        assert_eq!(
-            DROP_COUNT.load(Ordering::Relaxed),
-            1,
-            "DropCounter must be dropped exactly once"
-        );
-    }
-
-    // --- Verified::from_ref ---
-
-    #[test]
-    fn from_ref_is_same_address() {
-        let val = 42u32;
-        let verified: &Verified<u32> = Verified::from_ref(&val);
-        assert_eq!(
-            &val as *const u32 as *const u8, verified as *const _ as *const u8,
-            "from_ref must alias the original reference, not copy the value"
-        );
-    }
-
-    #[test]
-    fn from_ref_value_preserved() {
-        let val = String::from("test");
-        let verified: &Verified<String> = Verified::from_ref(&val);
-        assert_eq!(**verified, "test");
-    }
-
-    // --- AsRef<Verified<T>> for Verified<&T> ---
-
-    #[test]
-    fn verified_ref_as_ref_is_same_address() {
-        let val = 99u32;
-        let vref: Verified<&u32> = Verified::new_unchecked(&val);
-        let v: &Verified<u32> = vref.as_ref();
-        assert_eq!(
-            &val as *const u32 as *const u8, v as *const _ as *const u8,
-            "AsRef<Verified<T>> for Verified<&T> must alias the referent, not copy it"
-        );
-    }
-}

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 crate::safe_cell::{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()
@@ -141,10 +127,10 @@ mod tests {
         derive_key,
         encryption::v1::{Nonce, generate_salt},
     };
-    use crate::safe_cell::{SafeCell, SafeCellHandle as _};
+    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)
@@ -69,41 +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))
         }
     }
 
-    /// Key algorithm stored in the `useragent_client.key_type` column.
-    /// Values must stay stable — they are persisted in the database.
-    #[derive(Debug, Clone, Copy, PartialEq, Eq, FromSqlRow, AsExpression, strum::FromRepr)]
+    #[derive(Debug, FromSqlRow, AsExpression, Clone)]
     #[diesel(sql_type = Integer)]
-    #[repr(i32)]
-    pub enum KeyType {
-        Ed25519 = 1,
-        EcdsaSecp256k1 = 2,
-        Rsa = 3,
-    }
+    #[repr(transparent)] // hint compiler to optimize the wrapper struct away
+    pub struct ChainId(pub i32);
 
-    impl ToSql<Integer, Sqlite> for KeyType {
+    #[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 {
-            out.set_value(*self as i32);
-            Ok(IsNull::No)
-        }
-    }
-
-    impl FromSql<Integer, Sqlite> for KeyType {
-        fn from_sql(
-            mut bytes: <Sqlite as diesel::backend::Backend>::RawValue<'_>,
-        ) -> diesel::deserialize::Result<Self> {
-            let Some(SqliteType::Long) = bytes.value_type() else {
-                return Err("Expected Integer for KeyType".into());
-            };
-            let discriminant = bytes.read_long();
-            KeyType::from_repr(discriminant as i32)
-                .ok_or_else(|| format!("Unknown KeyType discriminant: {discriminant}").into())
+            ToSql::<Integer, Sqlite>::to_sql(&self.0, out)
         }
     }
 }
@@ -229,7 +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,
@@ -240,11 +251,9 @@ 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,
-    pub key_type: KeyType,
 }
 
 #[derive(Models, Queryable, Debug, Insertable, Selectable)]
@@ -272,7 +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>>,
@@ -295,7 +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,
 }
@@ -370,7 +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

@@ -1,18 +1,6 @@
-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,
-    crypto::integrity::{self, Verified, VerifiedEntity, verified::VerifiedFieldsAccessor},
+    actors::vault::Vault,
+    crypto::integrity,
     db::{
         self, DatabaseError,
         models::{
@@ -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 {
@@ -153,39 +153,12 @@ impl Engine {
     {
         let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
 
-        let verified_settings =
-            match integrity::lookup_verified_from_query(&mut conn, &self.keyholder, |conn| {
-                let context = context.clone();
-                Box::pin(async move {
-                    let grant = P::try_find_grant(&context, conn)
-                        .await
-                        .map_err(DatabaseError::from)?
-                        .ok_or_else(|| DatabaseError::from(diesel::result::Error::NotFound))?;
-
-                    Ok::<_, DatabaseError>((grant.common_settings_id, grant.settings))
-                })
-            })
-            .await
-            {
-                Ok(verified) => verified,
-                Err(integrity::Error::Database(DatabaseError::Connection(
-                    diesel::result::Error::NotFound,
-                ))) => return Err(PolicyError::NoMatchingGrant),
-                Err(err) => return Err(PolicyError::Integrity(err)),
-            };
-
-        let mut grant = P::try_find_grant(&context, &mut conn)
+        let grant = P::try_find_grant(&context, &mut conn)
             .await
             .map_err(DatabaseError::from)?
             .ok_or(PolicyError::NoMatchingGrant)?;
 
-        // IMPORTANT: policy evaluation uses extra non-integrity fields from Grant
-        // (e.g., per-policy ids), so we currently reload Grant after the query-native
-        // integrity check over canonicalized settings.
-        grant.settings = verified_settings
-            .inherit()
-            .entity
-            .drop_verification_provenance();
+        integrity::verify_entity(&mut conn, &self.vault, &grant.settings, grant.id).await?;
 
         let mut violations = check_shared_constraints(
             &context,
@@ -212,7 +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(),
                         })
@@ -234,28 +207,34 @@ 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>(
         &self,
         full_grant: CombinedSettings<P::Settings>,
-    ) -> Result<Verified<i32>, DatabaseError>
+    ) -> Result<i32, DatabaseError>
     where
         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),
@@ -285,23 +264,22 @@ impl Engine {
 
                     P::create_grant(&basic_grant, &full_grant.specific, conn).await?;
 
-                    let verified_entity_id =
-                        integrity::sign_entity(conn, &keyholder, &full_grant, basic_grant.id)
-                            .await
-                            .map_err(|_| diesel::result::Error::RollbackTransaction)?;
+                    integrity::sign_entity(conn, &vault, &full_grant, basic_grant.id)
+                        .await
+                        .map_err(|_| diesel::result::Error::RollbackTransaction)?;
 
-                    QueryResult::Ok(verified_entity_id)
+                    QueryResult::Ok(basic_grant.id)
                 })
             })
             .await?;
 
-        Ok(id.unqualify_origin())
+        Ok(id)
     }
 
     async fn list_one_kind<Kind: Policy, Y>(
         &self,
         conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    ) -> Result<Vec<Grant<Y>>, ListError>
+    ) -> Result<impl Iterator<Item = Grant<Y>>, ListError>
     where
         Y: From<Kind::Settings>,
     {
@@ -309,32 +287,16 @@ impl Engine {
             .await
             .map_err(DatabaseError::from)?;
 
-        let mut verified_grants = Vec::with_capacity(all_grants.len());
-
-        // Verify integrity of all grants before returning any results.
-        for grant in all_grants {
-            let VerifiedEntity {
-                entity: verified_settings,
-                entity_id: _,
-            } = integrity::verify_entity(
-                conn,
-                &self.keyholder,
-                grant.settings,
-                grant.common_settings_id,
-            )
-            .await?
-            .inherit();
-
-            verified_grants.push(Grant {
-                id: grant.id,
-                common_settings_id: grant.common_settings_id,
-                settings: verified_settings
-                    .drop_verification_provenance()
-                    .generalize(),
-            });
+        // Verify integrity of all grants before returning any results
+        for grant in &all_grants {
+            integrity::verify_entity(conn, &self.vault, &grant.settings, grant.id).await?;
         }
 
-        Ok(verified_grants)
+        Ok(all_grants.into_iter().map(|g| Grant {
+            id: g.id,
+            common_settings_id: g.common_settings_id,
+            settings: g.settings.generalize(),
+        }))
     }
 
     pub async fn list_all_grants(&self) -> Result<Vec<Grant<SpecificGrant>>, ListError> {
@@ -357,7 +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,
@@ -448,10 +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
@@ -615,7 +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
@@ -127,19 +125,19 @@ pub enum SpecificMeaning {
     TokenTransfer(token_transfers::Meaning),
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, arbiter_macros::Hashable)]
 pub struct TransactionRateLimit {
     pub count: u32,
     pub window: Duration,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, arbiter_macros::Hashable)]
 pub struct VolumeRateLimit {
     pub max_volume: U256,
     pub window: Duration,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash, arbiter_macros::Hashable)]
 pub struct SharedGrantSettings {
     pub wallet_access_id: i32,
     pub chain: ChainId,
@@ -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
@@ -200,7 +199,7 @@ pub enum SpecificGrant {
     TokenTransfer(token_transfers::Settings),
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, arbiter_macros::Hashable)]
 pub struct CombinedSettings<PolicyGrant> {
     pub shared: SharedGrantSettings,
     pub specific: PolicyGrant,
@@ -219,38 +218,3 @@ impl<P: Integrable> Integrable for CombinedSettings<P> {
     const KIND: &'static str = P::KIND;
     const VERSION: i32 = P::VERSION;
 }
-
-use crate::crypto::integrity::hashing::Hashable;
-
-impl Hashable for TransactionRateLimit {
-    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
-        self.count.hash(hasher);
-        self.window.hash(hasher);
-    }
-}
-
-impl Hashable for VolumeRateLimit {
-    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
-        self.max_volume.hash(hasher);
-        self.window.hash(hasher);
-    }
-}
-
-impl Hashable for SharedGrantSettings {
-    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
-        self.wallet_access_id.hash(hasher);
-        self.chain.hash(hasher);
-        self.valid_from.hash(hasher);
-        self.valid_until.hash(hasher);
-        self.max_gas_fee_per_gas.hash(hasher);
-        self.max_priority_fee_per_gas.hash(hasher);
-        self.rate_limit.hash(hasher);
-    }
-}
-
-impl<P: Hashable> Hashable for CombinedSettings<P> {
-    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
-        self.shared.hash(hasher);
-        self.specific.hash(hasher);
-    }
-}

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::{
-    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 super::{DatabaseID, EvalContext, EvalViolation};
 use crate::{
+    crypto::integrity::v1::Integrable,
+    db::models::{
+        EvmBasicGrant, EvmEtherTransferGrant, EvmEtherTransferGrantTarget, EvmEtherTransferLimit,
+        NewEvmEtherTransferLimit, SqliteTimestamp,
+    },
+    db::schema::{evm_basic_grant, evm_ether_transfer_limit, evm_transaction_log},
     db::{
-        models::{self, NewEvmEtherTransferGrant, NewEvmEtherTransferGrantTarget},
+        models::{NewEvmEtherTransferGrant, NewEvmEtherTransferGrantTarget},
         schema::{evm_ether_transfer_grant, evm_ether_transfer_grant_target},
     },
+    evm::policies::{
+        CombinedSettings, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
+        VolumeRateLimit,
+    },
     evm::{policies::Policy, utils},
 };
 
+use alloy::primitives::{Address, U256};
+use chrono::{DateTime, Duration, Utc};
+use diesel::{
+    dsl::{auto_type, insert_into},
+    prelude::*,
+    sqlite::Sqlite,
+};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use std::{collections::HashMap, fmt::Display};
+
 #[auto_type]
 fn grant_join() -> _ {
     evm_ether_transfer_grant::table.inner_join(
@@ -32,8 +34,6 @@ fn grant_join() -> _ {
     )
 }
 
-use super::{DatabaseID, EvalContext, EvalViolation};
-
 // Plain ether transfer
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Meaning {
@@ -46,13 +46,13 @@ 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)
     }
 }
 
 // A grant for ether transfers, which can be scoped to specific target addresses and volume limits
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, arbiter_macros::Hashable)]
 pub struct Settings {
     pub target: Vec<Address>,
     pub limit: VolumeRateLimit,
@@ -61,18 +61,9 @@ impl Integrable for Settings {
     const KIND: &'static str = "EtherTransfer";
 }
 
-use crate::crypto::integrity::hashing::Hashable;
-
-impl Hashable for Settings {
-    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
-        self.target.hash(hasher);
-        self.limit.hash(hasher);
-    }
-}
-
 impl From<Settings> for SpecificGrant {
-    fn from(val: Settings) -> SpecificGrant {
-        SpecificGrant::EtherTransfer(val)
+    fn from(val: Settings) -> Self {
+        Self::EtherTransfer(val)
     }
 }
 
@@ -83,9 +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,
@@ -110,10 +99,9 @@ async fn check_rate_limits(
     let mut violations = Vec::new();
     let window = grant.settings.specific.limit.window;
 
-    let past_transaction =
-        query_relevant_past_transaction(grant.common_settings_id, window, db).await?;
+    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)
@@ -163,10 +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,
@@ -201,7 +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:
@@ -250,20 +243,21 @@ impl Policy for EtherTransfer {
             })
             .collect();
 
+        let settings = Settings {
+            target: targets,
+            limit: VolumeRateLimit {
+                max_volume: utils::try_bytes_to_u256(&limit.max_volume)
+                    .map_err(|err| diesel::result::Error::DeserializationError(Box::new(err)))?,
+                window: Duration::seconds(limit.window_secs.into()),
+            },
+        };
+
         Ok(Some(Grant {
             id: grant.id,
             common_settings_id: grant.basic_grant_id,
             settings: CombinedSettings {
                 shared: SharedGrantSettings::try_from_model(basic_grant)?,
-                specific: Settings {
-                    target: targets,
-                    limit: VolumeRateLimit {
-                        max_volume: utils::try_bytes_to_u256(&limit.max_volume).map_err(|err| {
-                            diesel::result::Error::DeserializationError(Box::new(err))
-                        })?,
-                        window: chrono::Duration::seconds(limit.window_secs as i64),
-                    },
-                },
+                specific: settings,
             },
         }))
     }
@@ -274,7 +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(())
@@ -327,7 +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| {
@@ -351,7 +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 super::{EtherTransfer, Settings};
+use crate::{
+    db::{
+        self, DatabaseConnection,
+        models::{
+            EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, NewEvmTransactionLog, SqliteTimestamp,
+        },
+        schema::{evm_basic_grant, evm_transaction_log},
+    },
+    evm::{
+        policies::{
+            CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
+            VolumeRateLimit,
+        },
+        utils,
+    },
+};
+
 use alloy::primitives::{Address, Bytes, U256, address};
 use chrono::{Duration, Utc};
 use diesel::{SelectableHelper, insert_into};
 use diesel_async::RunQueryDsl;
 
-use crate::db::{
-    self, DatabaseConnection,
-    models::{
-        EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, NewEvmTransactionLog, SqliteTimestamp,
-    },
-    schema::{evm_basic_grant, evm_transaction_log},
-};
-use crate::evm::{
-    policies::{
-        CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
-        VolumeRateLimit,
-    },
-    utils,
-};
-
-use super::{EtherTransfer, Settings};
-
 const WALLET_ACCESS_ID: i32 = 1;
-const CHAIN_ID: u64 = 1;
+const CHAIN_ID: alloy::primitives::ChainId = 1;
 
 const ALLOWED: Address = address!("1111111111111111111111111111111111111111");
 const OTHER: Address = address!("2222222222222222222222222222222222222222");
@@ -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()),
         })
@@ -340,7 +341,7 @@ proptest::proptest! {
     ) {
         use rand::{SeedableRng, seq::SliceRandom};
         use sha2::Digest;
-        use crate::crypto::integrity::hashing::Hashable;
+        use arbiter_crypto::hashing::Hashable;
 
         let addrs: Vec<Address> = raw_addrs.iter().map(|b| Address::from(*b)).collect();
         let mut shuffled = addrs.clone();

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() -> _ {
@@ -56,13 +57,13 @@ 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)
     }
 }
 
 // A grant for token transfers, which can be scoped to specific target addresses and volume limits
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, arbiter_macros::Hashable)]
 pub struct Settings {
     pub token_contract: Address,
     pub target: Option<Address>,
@@ -72,19 +73,9 @@ impl Integrable for Settings {
     const KIND: &'static str = "TokenTransfer";
 }
 
-use crate::crypto::integrity::hashing::Hashable;
-
-impl Hashable for Settings {
-    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
-        self.token_contract.hash(hasher);
-        self.target.hash(hasher);
-        self.volume_limits.hash(hasher);
-    }
-}
-
 impl From<Settings> for SpecificGrant {
-    fn from(val: Settings) -> SpecificGrant {
-        SpecificGrant::TokenTransfer(val)
+    fn from(val: Settings) -> Self {
+        Self::TokenTransfer(val)
     }
 }
 
@@ -95,10 +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,
@@ -138,7 +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)
@@ -214,6 +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,
@@ -263,7 +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<_>>>()?;
@@ -286,16 +279,18 @@ impl Policy for TokenTransfer {
             }
         };
 
+        let settings = Settings {
+            token_contract: Address::from(token_contract),
+            target,
+            volume_limits,
+        };
+
         Ok(Some(Grant {
             id: token_grant.id,
             common_settings_id: token_grant.basic_grant_id,
             settings: CombinedSettings {
                 shared: SharedGrantSettings::try_from_model(basic_grant)?,
-                specific: Settings {
-                    token_contract: Address::from(token_contract),
-                    target,
-                    volume_limits,
-                },
+                specific: settings,
             },
         }))
     }
@@ -311,7 +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(),
@@ -360,7 +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| {
@@ -368,7 +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

@@ -1,25 +1,28 @@
-use alloy::primitives::{Address, Bytes, U256, address};
-use alloy::sol_types::SolCall;
+use super::{Settings, TokenTransfer};
+use crate::{
+    db::{
+        self, DatabaseConnection,
+        models::{EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, SqliteTimestamp},
+        schema::evm_basic_grant,
+    },
+    evm::{
+        abi::IERC20::transferCall,
+        policies::{
+            CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
+            VolumeRateLimit,
+        },
+        utils,
+    },
+};
+
+use alloy::{
+    primitives::{Address, Bytes, U256, address},
+    sol_types::SolCall,
+};
 use chrono::{Duration, Utc};
 use diesel::{SelectableHelper, insert_into};
 use diesel_async::RunQueryDsl;
 
-use crate::db::{
-    self, DatabaseConnection,
-    models::{EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, SqliteTimestamp},
-    schema::evm_basic_grant,
-};
-use crate::evm::{
-    abi::IERC20::transferCall,
-    policies::{
-        CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
-        VolumeRateLimit,
-    },
-    utils,
-};
-
-use super::{Settings, TokenTransfer};
-
 // DAI on Ethereum mainnet — present in the static token registry
 const CHAIN_ID: u64 = 1;
 const DAI: Address = address!("6B175474E89094C44Da98b954EedeAC495271d0F");
@@ -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(),
@@ -419,7 +420,7 @@ proptest::proptest! {
     ) {
         use rand::{SeedableRng, seq::SliceRandom};
         use sha2::Digest;
-        use crate::crypto::integrity::hashing::Hashable;
+        use arbiter_crypto::hashing::Hashable;
 
         let limits: Vec<VolumeRateLimit> = raw_limits
             .iter()

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

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

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 +1,8 @@
+use crate::{
+    grpc::{Convert, request_tracker::RequestTracker},
+    peers::client::{ClientConnection, auth},
+};
+use arbiter_crypto::authn;
 use arbiter_proto::{
     ClientMetadata,
     proto::{
@@ -16,23 +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},
-    crypto::integrity::Verified,
-    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().to_vec(),
-                    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
@@ -161,21 +127,17 @@ impl Receiver<auth::Inbound> for AuthTransportAdapter<'_> {
                         .await;
                     return None;
                 };
-                let Ok(pubkey) = <[u8; 32]>::try_from(pubkey) else {
-                    let _ = self.send_auth_result(ProtoAuthResult::InvalidKey).await;
-                    return None;
-                };
-                let Ok(pubkey) = ed25519_dalek::VerifyingKey::from_bytes(&pubkey) else {
+                let Ok(pubkey) = authn::PublicKey::try_from(pubkey.as_slice()) else {
                     let _ = self.send_auth_result(ProtoAuthResult::InvalidKey).await;
                     return None;
                 };
                 Some(auth::Inbound::AuthChallengeRequest {
                     pubkey,
-                    metadata: client_metadata_from_proto(client_info),
+                    metadata: client_info.convert(),
                 })
             }
             AuthRequestPayload::ChallengeSolution(ProtoAuthChallengeSolution { signature }) => {
-                let Ok(signature) = ed25519_dalek::Signature::try_from(signature.as_slice()) else {
+                let Ok(signature) = authn::Signature::try_from(signature.as_slice()) else {
                     let _ = self
                         .send_auth_result(ProtoAuthResult::InvalidSignature)
                         .await;
@@ -189,19 +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 {
-    ClientMetadata {
-        name: metadata.name,
-        description: metadata.description,
-        version: metadata.version,
+impl Convert for ProtoClientInfo {
+    type Output = ClientMetadata;
+
+    fn convert(self) -> Self::Output {
+        ClientMetadata {
+            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<Verified<i32>, auth::Error> {
+) -> 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();
+    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!(?pubkey, "User authenticated successfully");
-    dispatch_loop(bi, actor, oob_receiver, request_tracker).await;
-    actor_for_cleanup.kill();
+    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 +1,5 @@
+use crate::{grpc::request_tracker::RequestTracker, peers::user_agent::auth};
+use arbiter_crypto::authn;
 use arbiter_proto::{
     proto::user_agent::{
         UserAgentRequest, UserAgentResponse,
@@ -5,31 +7,25 @@ use arbiter_proto::{
             self as proto_auth, AuthChallenge as ProtoAuthChallenge,
             AuthChallengeRequest as ProtoAuthChallengeRequest,
             AuthChallengeSolution as ProtoAuthChallengeSolution, AuthResult as ProtoAuthResult,
-            KeyType as ProtoKeyType, request::Payload as AuthRequestPayload,
-            response::Payload as AuthResponsePayload,
+            request::Payload as AuthRequestPayload, response::Payload as AuthResponsePayload,
         },
         user_agent_request::Payload as UserAgentRequestPayload,
         user_agent_response::Payload as UserAgentResponsePayload,
     },
     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::{AuthPublicKey, UserAgentConnection, auth},
-    db::models::KeyType,
-    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 {
@@ -39,19 +35,35 @@ 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),
-                })),
+                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
+    }
 }
 
 #[async_trait]
@@ -62,8 +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())
@@ -141,28 +160,8 @@ impl Receiver<auth::Inbound> for AuthTransportAdapter<'_> {
             AuthRequestPayload::ChallengeRequest(ProtoAuthChallengeRequest {
                 pubkey,
                 bootstrap_token,
-                key_type,
             }) => {
-                let Ok(key_type) = ProtoKeyType::try_from(key_type) else {
-                    warn!(
-                        event = "received request with invalid key type",
-                        "grpc.useragent.auth_adapter"
-                    );
-                    return None;
-                };
-                let key_type = match key_type {
-                    ProtoKeyType::Ed25519 => KeyType::Ed25519,
-                    ProtoKeyType::EcdsaSecp256k1 => KeyType::EcdsaSecp256k1,
-                    ProtoKeyType::Rsa => KeyType::Rsa,
-                    ProtoKeyType::Unspecified => {
-                        warn!(
-                            event = "received request with unspecified key type",
-                            "grpc.useragent.auth_adapter"
-                        );
-                        return None;
-                    }
-                };
-                let Ok(pubkey) = AuthPublicKey::try_from((key_type, pubkey)) else {
+                let Ok(pubkey) = authn::PublicKey::try_from(pubkey.as_slice()) else {
                     warn!(
                         event = "received request with invalid public key",
                         "grpc.useragent.auth_adapter"
@@ -183,12 +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<AuthPublicKey, 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,
@@ -66,7 +66,7 @@ async fn handle_wallet_create(
 ) -> Result<Option<UserAgentResponsePayload>, Status> {
     let result = match actor.ask(HandleEvmWalletCreate {}).await {
         Ok((wallet_id, address)) => WalletCreateResult::Wallet(WalletEntry {
-            id: wallet_id.drop_verification_provenance(),
+            id: wallet_id,
             address: address.to_vec(),
         }),
         Err(err) => {
@@ -121,9 +121,6 @@ async fn handle_grant_list(
                 })
                 .collect(),
         }),
-        Err(kameo::error::SendError::HandlerError(GrantMutationError::VaultSealed)) => {
-            EvmGrantListResult::Error(ProtoEvmError::VaultSealed.into())
-        }
         Err(err) => {
             warn!(error = ?err, "Failed to list EVM grants");
             EvmGrantListResult::Error(ProtoEvmError::Internal.into())
@@ -150,7 +147,7 @@ async fn handle_grant_create(
         .try_convert()?;
 
     let result = match actor.ask(HandleGrantCreate { basic, grant }).await {
-        Ok(grant_id) => EvmGrantCreateResult::GrantId(grant_id.drop_verification_provenance()),
+        Ok(grant_id) => EvmGrantCreateResult::GrantId(grant_id),
         Err(kameo::error::SendError::HandlerError(GrantMutationError::VaultSealed)) => {
             EvmGrantCreateResult::Error(ProtoEvmError::VaultSealed.into())
         }

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 +1,15 @@
+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,
     user_agent::{
@@ -15,23 +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),
     })
@@ -41,7 +42,7 @@ pub(super) fn out_of_band_payload(oob: OutOfBand) -> UserAgentResponsePayload {
     match oob {
         OutOfBand::ClientConnectionRequest { profile } => wrap_sdk_client_response(
             SdkClientResponsePayload::ConnectionRequest(ProtoSdkClientConnectionRequest {
-                pubkey: profile.pubkey.to_bytes().to_vec(),
+                pubkey: profile.pubkey.to_bytes(),
                 info: Some(ProtoClientMetadata {
                     name: profile.metadata.name,
                     description: profile.metadata.description,
@@ -51,7 +52,7 @@ pub(super) fn out_of_band_payload(oob: OutOfBand) -> UserAgentResponsePayload {
         ),
         OutOfBand::ClientConnectionCancel { pubkey } => wrap_sdk_client_response(
             SdkClientResponsePayload::ConnectionCancel(ProtoSdkClientConnectionCancel {
-                pubkey: pubkey.to_bytes().to_vec(),
+                pubkey: pubkey.to_bytes(),
             }),
         ),
     }
@@ -74,14 +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,
     }
 }
 
@@ -89,10 +90,8 @@ async fn handle_connection_response(
     actor: &ActorRef<UserAgentSession>,
     resp: ProtoSdkClientConnectionResponse,
 ) -> Result<Option<UserAgentResponsePayload>, Status> {
-    let pubkey_bytes = <[u8; 32]>::try_from(resp.pubkey)
-        .map_err(|_| Status::invalid_argument("Invalid Ed25519 public key length"))?;
-    let pubkey = ed25519_dalek::VerifyingKey::from_bytes(&pubkey_bytes)
-        .map_err(|_| Status::invalid_argument("Invalid Ed25519 public key"))?;
+    let pubkey = authn::PublicKey::try_from(resp.pubkey.as_slice())
+        .map_err(|()| Status::invalid_argument("Invalid ML-DSA public key"))?;
 
     actor
         .ask(HandleNewClientApprove {
@@ -117,12 +116,17 @@ async fn handle_list(
                 .into_iter()
                 .map(|(client, metadata)| ProtoSdkClientEntry {
                     id: client.id,
-                    pubkey: client.public_key,
+                    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(),
@@ -143,7 +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");
@@ -183,7 +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::{
-    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,
-        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 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, request::Payload as VaultRequestPayload,
+            response::Payload as VaultResponsePayload,
         },
     },
 };
-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

@@ -1,15 +1,12 @@
 use crate::context::ServerContext;
 
-#[macro_use]
-extern crate macro_rules_attribute;
-
 pub mod actors;
 pub mod context;
 pub mod crypto;
 pub mod db;
 pub mod evm;
 pub mod grpc;
-pub mod safe_cell;
+pub mod peers;
 pub mod utils;
 
 pub struct Server {
@@ -17,7 +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

@@ -1,30 +1,31 @@
-use arbiter_proto::{
-    ClientMetadata, format_challenge,
-    transport::{Bi, expect_message},
-};
-use chrono::Utc;
-use diesel::{
-    ExpressionMethods as _, OptionalExtension as _, QueryDsl as _, SelectableHelper as _,
-    dsl::insert_into, update,
-};
-use diesel_async::RunQueryDsl as _;
-use ed25519_dalek::{Signature, VerifyingKey};
-use kameo::{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, Verified, verified::VerifiedFieldsAccessor},
+    crypto::integrity::{self, AttestationStatus},
     db::{
         self,
         models::{ProgramClientMetadata, SqliteTimestamp},
         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 {
@@ -62,35 +63,33 @@ pub enum ApproveError {
 #[derive(Debug, Clone)]
 pub enum Inbound {
     AuthChallengeRequest {
-        pubkey: VerifyingKey,
+        pubkey: authn::PublicKey,
         metadata: ClientMetadata,
     },
     AuthChallengeSolution {
-        signature: Signature,
+        signature: authn::Signature,
     },
 }
 
 #[derive(Debug, Clone)]
 pub enum Outbound {
-    AuthChallenge { pubkey: VerifyingKey, 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: &VerifyingKey,
-) -> Result<Option<(i32, i32)>, Error> {
-    let pubkey_bytes = pubkey.as_bytes().to_vec();
+    pubkey: &authn::PublicKey,
+) -> 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");
         Error::DatabasePoolUnavailable
     })?;
     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| {
@@ -99,56 +98,44 @@ async fn get_current_nonce_and_id(
         })
 }
 
-/// 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(
+async fn verify_integrity(
     db: &db::DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
-    pubkey: &VerifyingKey,
-) -> Result<i32, Error> {
-    let pubkey_bytes = pubkey.as_bytes().to_vec();
-
-    let mut conn = db.get().await.map_err(|e| {
+    vault: &ActorRef<Vault>,
+    pubkey: &authn::PublicKey,
+) -> Result<(), Error> {
+    let mut db_conn = db.get().await.map_err(|e| {
         error!(error = ?e, "Database pool error");
         Error::DatabasePoolUnavailable
     })?;
 
-    conn.exclusive_transaction(|conn| {
-        let keyholder = keyholder.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?;
+    let id = get_client_id(db, pubkey).await?.ok_or_else(|| {
+        error!("Client not found during integrity verification");
+        Error::DatabaseOperationFailed
+    })?;
 
-            integrity::sign_entity(
-                conn,
-                &keyholder,
-                &ClientCredentials {
-                    pubkey: *pubkey,
-                    nonce: new_nonce,
-                },
-                id,
-            )
-            .await
-            .map_err(|e| {
-                error!(?e, "Integrity sign failed after nonce update");
-                Error::DatabaseOperationFailed
-            })?
-            .drop_verification_provenance();
-
-            Ok(new_nonce)
-        })
-    })
+    let attestation = integrity::verify_entity(
+        &mut db_conn,
+        vault,
+        &ClientCredentials {
+            pubkey: pubkey.clone(),
+        },
+        id,
+    )
     .await
+    .map_err(|e| {
+        error!(?e, "Integrity verification failed");
+        Error::IntegrityCheckFailed
+    })?;
+
+    if attestation != AttestationStatus::Attested {
+        error!("Integrity attestation unavailable for client {id}");
+        return Err(Error::IntegrityCheckFailed);
+    }
+
+    Ok(())
 }
 
-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 })
@@ -170,11 +157,13 @@ async fn approve_new_client(
 
 async fn insert_client(
     db: &db::DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
-    pubkey: &VerifyingKey,
+    vault: &ActorRef<Vault>,
+    pubkey: &authn::PublicKey,
     metadata: &ClientMetadata,
-) -> Result<Verified<i32>, Error> {
-    use crate::db::schema::{client_metadata, program_client};
+) -> Result<i32, Error> {
+    use crate::db::schema::client_metadata;
+
+    let pubkey = pubkey.clone();
     let metadata = metadata.clone();
 
     let mut conn = db.get().await.map_err(|e| {
@@ -183,10 +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),
@@ -199,21 +187,19 @@ async fn insert_client(
 
             let client_id = insert_into(program_client::table)
                 .values((
-                    program_client::public_key.eq(pubkey.as_bytes().to_vec()),
+                    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)
                 .get_result::<i32>(conn)
                 .await?;
 
-            let verified_id = integrity::sign_entity(
+            integrity::sign_entity(
                 conn,
-                &keyholder,
+                &vault,
                 &ClientCredentials {
-                    pubkey: *pubkey,
-                    nonce: NONCE_START,
+                    pubkey: pubkey.clone(),
                 },
                 client_id,
             )
@@ -221,10 +207,9 @@ async fn insert_client(
             .map_err(|e| {
                 error!(error = ?e, "Failed to sign integrity tag for new client key");
                 Error::DatabaseOperationFailed
-            })?
-            .unqualify_origin();
+            })?;
 
-            Ok(verified_id)
+            Ok(client_id)
         })
     })
     .await
@@ -303,14 +288,16 @@ async fn sync_client_metadata(
 
 async fn challenge_client<T>(
     transport: &mut T,
-    pubkey: VerifyingKey,
-    nonce: i32,
+    pubkey: authn::PublicKey,
+    challenge: AuthChallenge,
 ) -> Result<(), Error>
 where
     T: Bi<Inbound, Result<Outbound, Error>> + ?Sized,
 {
     transport
-        .send(Ok(Outbound::AuthChallenge { pubkey, nonce }))
+        .send(Ok(Outbound::AuthChallenge {
+            challenge: challenge.clone(),
+        }))
         .await
         .map_err(|e| {
             error!(error = ?e, "Failed to send auth challenge");
@@ -327,20 +314,15 @@ where
         Error::Transport
     })?;
 
-    let formatted = format_challenge(nonce, pubkey.as_bytes());
-
-    pubkey.verify_strict(&formatted, &signature).map_err(|_| {
+    if !pubkey.verify(&challenge, CLIENT_CONTEXT, &signature) {
         error!("Challenge solution verification failed");
-        Error::InvalidChallengeSolution
-    })?;
+        return Err(Error::InvalidChallengeSolution);
+    }
 
     Ok(())
 }
 
-pub async fn authenticate<T>(
-    props: &mut ClientConnection,
-    transport: &mut T,
-) -> Result<Verified<i32>, Error>
+pub async fn authenticate<T>(props: &mut ClientConnection, transport: &mut T) -> Result<i32, Error>
 where
     T: Bi<Inbound, Result<Outbound, Error>> + Send + ?Sized,
 {
@@ -348,45 +330,25 @@ where
         return Err(Error::Transport);
     };
 
-    // fixme! triage needed: probable regretion since in match->Some get_current_nonce_and_id called only once instead of twice
-    let client_id = match get_current_nonce_and_id(&props.db, &pubkey).await? {
-        Some((nonce, id)) => {
-            let mut db_conn = props.db.get().await.map_err(|e| {
-                error!(error = ?e, "Database pool error");
-                Error::DatabasePoolUnavailable
-            })?;
-
-            integrity::verify_entity(
-                &mut db_conn,
-                &props.actors.key_holder,
-                ClientCredentials { pubkey, nonce },
-                id,
-            )
-            .await
-            .map_err(|e| {
-                error!(?e, "Integrity verification failed");
-                Error::IntegrityCheckFailed
-            })?
-            .inherit()
-            .entity_id
-            .unqualify_origin()
-        }
-        None => {
-            approve_new_client(
-                &props.actors,
-                ClientProfile {
-                    pubkey,
-                    metadata: metadata.clone(),
-                },
-            )
-            .await?;
-            insert_client(&props.db, &props.actors.key_holder, &pubkey, &metadata).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
+    } else {
+        approve_new_client(
+            &props.actors,
+            ClientProfile {
+                pubkey: pubkey.clone(),
+                metadata: metadata.clone(),
+            },
+        )
+        .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?;
+    sync_client_metadata(&props.db, client_id, &metadata).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

@@ -1,42 +1,35 @@
+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, hashing::Hashable},
-    db,
-};
-
 #[derive(Debug, Clone)]
 pub struct ClientProfile {
-    pub pubkey: ed25519_dalek::VerifyingKey,
+    pub pubkey: authn::PublicKey,
     pub metadata: ClientMetadata,
 }
 
+#[derive(Hashable)]
 pub struct ClientCredentials {
-    pub pubkey: ed25519_dalek::VerifyingKey,
-    pub nonce: i32,
+    pub pubkey: authn::PublicKey,
 }
 
 impl Integrable for ClientCredentials {
     const KIND: &'static str = "client_credentials";
 }
 
-impl Hashable for ClientCredentials {
-    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
-        hasher.update(self.pubkey.as_bytes());
-        self.nonce.hash(hasher);
-    }
-}
-
 pub struct ClientConnection {
     pub(crate) db: db::DatabasePool,
     pub(crate) actors: GlobalActors,
 }
 
 impl ClientConnection {
-    pub fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
+    pub const fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
         Self { db, actors }
     }
 }
@@ -48,7 +41,9 @@ pub async fn connect_client<T>(mut props: ClientConnection, transport: &mut T)
 where
     T: Bi<auth::Inbound, Result<auth::Outbound, auth::Error>> + Send + ?Sized,
 {
-    match auth::authenticate(&mut props, transport).await {
+    let fut = auth::authenticate(&mut props, transport);
+    println!("authenticate future size: {}", size_of_val(&fut));
+    match fut.await {
         Ok(client_id) => {
             ClientSession::spawn(ClientSession::new(props, client_id));
             info!("Client authenticated, session started");

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

@@ -1,29 +1,26 @@
-use kameo::{Actor, messages};
-use tracing::error;
-
-use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
-
+use super::ClientConnection;
 use crate::{
     actors::{
-        client::ClientConnection,
+        GlobalActors,
         evm::{ClientSignTransaction, SignTransactionError},
         flow_coordinator::RegisterClient,
-        keyholder::KeyHolderState,
+        vault::VaultState,
     },
-    crypto::integrity::Verified,
+    db,
     evm::VetError,
 };
 
-#[cfg(test)]
-use crate::{actors::GlobalActors, db};
+use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
+use kameo::{Actor, messages};
+use tracing::error;
 
 pub struct ClientSession {
     props: ClientConnection,
-    client_id: Verified<i32>,
+    client_id: i32,
 }
 
 impl ClientSession {
-    pub(crate) fn new(props: ClientConnection, client_id: Verified<i32>) -> Self {
+    pub(crate) const fn new(props: ClientConnection, client_id: i32) -> Self {
         Self { props, client_id }
     }
 }
@@ -31,13 +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);
             }
         };
@@ -56,7 +53,7 @@ impl ClientSession {
             .actors
             .evm
             .ask(ClientSignTransaction {
-                client_id: *self.client_id,
+                client_id: self.client_id,
                 wallet_address,
                 transaction,
             })
@@ -94,12 +91,11 @@ impl Actor for ClientSession {
 }
 
 impl ClientSession {
-    #[cfg(test)]
-    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,
-            client_id: Verified::new_unchecked(0),
+            client_id: 0,
         }
     }
 }

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

@@ -1,18 +1,19 @@
+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::{
-    AuthPublicKey, UserAgentConnection,
-    auth::state::{AuthContext, AuthStateMachine},
-};
-
 mod state;
-use state::*;
 
 #[derive(Debug, Clone)]
 pub enum Inbound {
     AuthChallengeRequest {
-        pubkey: AuthPublicKey,
+        pubkey: authn::PublicKey,
         bootstrap_token: Option<String>,
     },
     AuthChallengeSolution {
@@ -30,32 +31,23 @@ pub enum Error {
 }
 
 impl Error {
-    #[track_caller]
-    pub(super) fn internal(details: impl Into<String>, err: &impl std::fmt::Debug) -> Self {
-        let details = details.into();
-        let caller = std::panic::Location::caller();
-        error!(
-            caller_file = %caller.file(),
-            caller_line = caller.line(),
-            caller_column = caller.column(),
-            details = %details,
-            error = ?err,
-            "Internal error"
-        );
-
-        Self::Internal { details }
+    fn internal(details: impl Into<String>) -> Self {
+        Self::Internal {
+            details: details.into(),
+        }
     }
 }
 
 impl From<diesel::result::Error> for Error {
     fn from(e: diesel::result::Error) -> Self {
-        Self::internal("Database error", &e)
+        error!(?e, "Database error");
+        Self::internal("Database error")
     }
 }
 
 #[derive(Debug, Clone)]
 pub enum Outbound {
-    AuthChallenge { nonce: i32 },
+    AuthChallenge { challenge: AuthChallenge },
     AuthSuccess,
 }
 
@@ -63,12 +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,
@@ -79,21 +70,20 @@ fn parse_auth_event(payload: Inbound) -> AuthEvents {
 
 pub async fn authenticate<T>(
     props: &mut UserAgentConnection,
-    transport: T,
-) -> Result<AuthPublicKey, 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 std::{borrow::Cow, collections::HashMap};
-
+use super::{OutOfBand, UserAgentConnection};
+use crate::{
+    actors::{
+        flow_coordinator::client_connect_approval::ClientApprovalController,
+        useragent_registry::ConnectUseragent,
+    },
+    peers::client::ClientProfile,
+};
+use arbiter_crypto::authn;
 use arbiter_proto::transport::Sender;
-use async_trait::async_trait;
-use ed25519_dalek::VerifyingKey;
+
 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")]
@@ -47,52 +45,27 @@ impl Error {
 }
 
 pub struct PendingClientApproval {
+    pubkey: authn::PublicKey,
     controller: ActorRef<ClientApprovalController>,
 }
 
 pub struct UserAgentSession {
     props: UserAgentConnection,
-    state: UserAgentStateMachine<DummyContext>,
     sender: Box<dyn Sender<OutOfBand>>,
 
-    pending_client_approvals: HashMap<VerifyingKey, PendingClientApproval>,
+    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]
@@ -118,8 +91,13 @@ impl UserAgentSession {
             return;
         }
 
-        self.pending_client_approvals
-            .insert(client.pubkey, PendingClientApproval { controller });
+        self.pending_client_approvals.insert(
+            client.pubkey.to_bytes(),
+            PendingClientApproval {
+                pubkey: client.pubkey,
+                controller,
+            },
+        );
     }
 }
 
@@ -128,23 +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)
     }
@@ -158,14 +133,18 @@ impl Actor for UserAgentSession {
         let cancelled_pubkey = self
             .pending_client_approvals
             .iter()
-            .find_map(|(k, v)| (v.controller.id() == id).then_some(*k));
+            .find_map(|(k, v)| (v.controller.id() == id).then_some(k.clone()));
 
-        if let Some(pubkey) = cancelled_pubkey {
-            self.pending_client_approvals.remove(&pubkey);
+        if let Some(pubkey_bytes) = cancelled_pubkey {
+            let Some(approval) = self.pending_client_approvals.remove(&pubkey_bytes) else {
+                return Ok(std::ops::ControlFlow::Continue(()));
+            };
 
             if let Err(e) = self
                 .sender
-                .send(OutOfBand::ClientConnectionCancel { pubkey })
+                .send(OutOfBand::ClientConnectionCancel {
+                    pubkey: approval.pubkey,
+                })
                 .await
             {
                 error!(

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/src/utils.rs

@@ -1,5 +1,3 @@
-use std::ops::Deref;
-
 struct DeferClosure<F: FnOnce()> {
     f: Option<F>,
 }
@@ -16,19 +14,3 @@ impl<F: FnOnce()> Drop for DeferClosure<F> {
 pub fn defer<F: FnOnce()>(f: F) -> impl Drop + Sized {
     DeferClosure { f: Some(f) }
 }
-
-/// A trait for casting between two transparently wrapped types with identical memory layouts.
-///
-/// [`ReinterpretWrapper`] enables zero-cost conversions between two types (`Self` and `Counterpart`)
-/// that wrap the same underlying data but differ in how that data is presented. Both types must
-/// transparently wrap the same "deref target" and provide bidirectional `AsRef` conversions.
-pub trait ReinterpretWrapper<Counterpart>
-where
-    Self: Deref<Target = Self::Inner> + AsRef<Counterpart>,
-    Counterpart: Deref<Target = Self::Inner> + AsRef<Self>,
-{
-    /// The shared target type that both `Self` and `Counterpart` transparently wrap.
-    type Inner;
-    /// Reinterprets `Self` as `Counterpart`.
-    fn reinterpret(self) -> Counterpart;
-}

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

@@ -1,20 +1,22 @@
-use arbiter_proto::ClientMetadata;
-use arbiter_proto::transport::{Receiver, Sender};
+use super::common::ChannelTransport;
+use arbiter_crypto::{
+    authn::{self, AuthChallenge, CLIENT_CONTEXT},
+    safecell::{SafeCell, SafeCellHandle as _},
+};
+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},
-    safe_cell::{SafeCell, SafeCellHandle as _},
+    peers::client::{ClientConnection, ClientCredentials, auth, connect_client},
 };
+
 use diesel::{ExpressionMethods as _, NullableExpressionMethods as _, QueryDsl as _, insert_into};
 use diesel_async::RunQueryDsl;
-use ed25519_dalek::Signer 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 {
@@ -24,10 +26,14 @@ 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,
-    pubkey: ed25519_dalek::VerifyingKey,
+    pubkey: VerifyingKey<MlDsa87>,
     metadata: &ClientMetadata,
 ) {
     use arbiter_server::db::schema::{client_metadata, program_client};
@@ -45,7 +51,7 @@ async fn insert_registered_client(
         .unwrap();
     let client_id: i32 = insert_into(program_client::table)
         .values((
-            program_client::public_key.eq(pubkey.to_bytes().to_vec()),
+            program_client::public_key.eq(pubkey.encode().0.to_vec()),
             program_client::metadata_id.eq(metadata_id),
         ))
         .returning(program_client::id)
@@ -53,28 +59,35 @@ async fn insert_registered_client(
         .await
         .unwrap();
 
-    let _ = integrity::sign_entity(
+    integrity::sign_entity(
         &mut conn,
-        &actors.key_holder,
-        &ClientCredentials { pubkey, nonce: 1 },
+        &actors.vault,
+        &ClientCredentials {
+            pubkey: pubkey.into(),
+        },
         client_id,
     )
     .await
     .unwrap();
 }
 
+fn sign_client_challenge(key: &SigningKey<MlDsa87>, challenge: &AuthChallenge) -> authn::Signature {
+    let challenge = challenge.format();
+    key.signing_key()
+        .sign_deterministic(&challenge, CLIENT_CONTEXT)
+        .unwrap()
+        .into()
+}
+
 async fn insert_bootstrap_sentinel_useragent(db: &db::DatabasePool) {
     let mut conn = db.get().await.unwrap();
-    let sentinel_key = ed25519_dalek::SigningKey::generate(&mut rand::rng())
-        .verifying_key()
-        .to_bytes()
+    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();
@@ -85,7 +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()),
         })
@@ -96,7 +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();
@@ -107,11 +120,11 @@ pub async fn test_unregistered_pubkey_rejected() {
         connect_client(props, &mut server_transport).await;
     });
 
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key(),
+            pubkey: verifying_key(&new_key).into(),
             metadata: metadata("client", Some("desc"), Some("1.0.0")),
         })
         .await
@@ -123,18 +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 = ed25519_dalek::SigningKey::generate(&mut rand::rng());
+    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();
@@ -147,7 +160,7 @@ pub async fn test_challenge_auth() {
     // Send challenge request
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key(),
+            pubkey: verifying_key(&new_key).into(),
             metadata: metadata("client", Some("desc"), Some("1.0.0")),
         })
         .await
@@ -160,15 +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 formatted_challenge = arbiter_proto::format_challenge(challenge.1, challenge.0.as_bytes());
-    let signature = new_key.sign(&formatted_challenge);
+    let signature = sign_client_challenge(&new_key, &challenge);
 
     test_transport
         .send(auth::Inbound::AuthChallengeSolution { signature })
@@ -191,13 +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 = ed25519_dalek::SigningKey::generate(&mut rand::rng());
+    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);
 
@@ -209,18 +227,18 @@ pub async fn test_metadata_unchanged_does_not_append_history() {
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key(),
+            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 = new_key.sign(&arbiter_proto::format_challenge(nonce, pubkey.as_bytes()));
+    let signature = sign_client_challenge(&new_key, &challenge);
     test_transport
         .send(auth::Inbound::AuthChallengeSolution { signature })
         .await
@@ -248,17 +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 = ed25519_dalek::SigningKey::generate(&mut rand::rng());
+    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);
@@ -271,23 +289,23 @@ pub async fn test_metadata_change_appends_history_and_repoints_binding() {
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key(),
+            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 = new_key.sign(&arbiter_proto::format_challenge(nonce, pubkey.as_bytes()));
+    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();
 
     {
@@ -335,11 +353,11 @@ 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;
 
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
     let requested = metadata("client", Some("desc"), Some("1.0.0"));
 
     {
@@ -357,7 +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().to_bytes().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)
@@ -374,7 +392,7 @@ pub async fn test_challenge_auth_rejects_integrity_tag_mismatch() {
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key(),
+            pubkey: verifying_key(&new_key).into(),
             metadata: requested,
         })
         .await