docs: updated to new auth challenge format and removed stale TOCTOU race condition note

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.
 

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.
 

IMPLEMENTATION.md

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

mise.lock

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

mise.toml

@@ -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

@@ -26,7 +26,6 @@ thiserror = "2.0.18"
 async-trait = "0.1.89"
 futures = "0.3.32"
 tokio-stream = { version = "0.1.18", features = ["full"] }
-kameo = "0.19.2"
 prost-types = { version = "0.14.3", features = ["chrono"] }
 x25519-dalek = { version = "2.0.1", features = ["getrandom"] }
 rstest = "0.26.1"
@@ -47,3 +46,6 @@ miette = { version = "7.6.0", features = ["fancy", "serde"] }
 mutants = "0.0.4"
 ml-dsa = { version = "0.1.0-rc.8", features = ["zeroize"] }
 base64 = "0.22.1"
+kameo = {git = "https://github.com/hdbg/kameo.git", rev = "805b417"}
+kameo_actors = {git = "https://github.com/hdbg/kameo.git", rev = "805b417"}
+

server/crates/arbiter-client/Cargo.toml

@@ -24,3 +24,4 @@ http = "1.4.0"
 rustls-webpki = { version = "0.103.10", features = ["aws-lc-rs"] }
 async-trait.workspace = true
 rand.workspace = true
+chrono.workspace = true

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

@@ -1,4 +1,4 @@
-use arbiter_crypto::authn::{CLIENT_CONTEXT, SigningKey, format_challenge};
+use arbiter_crypto::authn::{self, CLIENT_CONTEXT, SigningKey};
 use arbiter_proto::{
     ClientMetadata,
     proto::{
@@ -15,6 +15,7 @@ use arbiter_proto::{
         shared::ClientInfo as ProtoClientInfo,
     },
 };
+use chrono::DateTime;
 
 use crate::{
     storage::StorageError,
@@ -23,6 +24,8 @@ use crate::{
 
 #[derive(Debug, thiserror::Error)]
 pub enum AuthError {
+    #[error("Server sent invalid auth challenge")]
+    InvalidChallenge,
     #[error("Auth challenge was not returned by server")]
     MissingAuthChallenge,
 
@@ -98,7 +101,15 @@ async fn send_auth_challenge_solution(
     key: &SigningKey,
     challenge: AuthChallenge,
 ) -> std::result::Result<(), AuthError> {
-    let challenge_payload = format_challenge(challenge.nonce, &challenge.pubkey);
+    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)?

server/crates/arbiter-crypto/Cargo.toml

@@ -6,13 +6,14 @@ edition = "2024"
 [dependencies]
 ml-dsa = {workspace = true, optional = true }
 rand = {workspace = true, optional = true}
-base64 = {workspace = true, optional = true }
 memsafe = {version = "0.4.0", optional = true}
+x-wing = { version = "0.1.0-rc.0", features = ["zeroize"] }
+chrono.workspace = true
 
 [lints]
 workspace = true
 
 [features]
 default = ["authn", "safecell"]
-authn = ["dep:ml-dsa", "dep:rand", "dep:base64"]
+authn = ["dep:ml-dsa", "dep:rand"]
 safecell = ["dep:memsafe"]

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

@@ -1,15 +1,56 @@
-use base64::{Engine as _, prelude::BASE64_STANDARD};
+use std::hash::Hash;
+
+use chrono::{DateTime, Utc};
 use ml_dsa::{
     EncodedVerifyingKey, Error, KeyGen, MlDsa87, Seed, Signature as MlDsaSignature,
     SigningKey as MlDsaSigningKey, VerifyingKey as MlDsaVerifyingKey, signature::Keypair as _,
 };
+use rand::RngExt;
 
 pub static CLIENT_CONTEXT: &[u8] = b"arbiter_client";
 pub static USERAGENT_CONTEXT: &[u8] = b"arbiter_user_agent";
 
-pub fn format_challenge(nonce: i32, pubkey: &[u8]) -> Vec<u8> {
-    let concat_form = format!("{}:{}", nonce, BASE64_STANDARD.encode(pubkey));
-    concat_form.into_bytes()
+const NONCE_SIZE: usize = 32;
+
+#[derive(Debug, Clone)]
+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, ()> {
+        let random_nonce = nonce.as_array().ok_or(())?;
+        Ok(AuthChallenge {
+            nonce: *random_nonce,
+            timestamp: DateTime::from_timestamp_nanos(timestamp),
+        })
+    }
 }
 
 pub type KeyParams = MlDsa87;
@@ -17,6 +58,12 @@ pub type KeyParams = MlDsa87;
 #[derive(Clone, Debug, PartialEq)]
 pub struct PublicKey(Box<MlDsaVerifyingKey<KeyParams>>);
 
+impl Hash for PublicKey {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        self.to_bytes().hash(state);
+    }
+}
+
 #[derive(Clone, Debug, PartialEq)]
 pub struct Signature(Box<MlDsaSignature<KeyParams>>);
 
@@ -28,12 +75,10 @@ impl PublicKey {
         self.0.encode().to_vec()
     }
 
-    pub fn verify(&self, nonce: i32, context: &[u8], signature: &Signature) -> bool {
-        self.0.verify_with_context(
-            &format_challenge(nonce, &self.to_bytes()),
-            context,
-            &signature.0,
-        )
+    pub fn verify(&self, challenge: &AuthChallenge, context: &[u8], signature: &Signature) -> bool {
+        let challenge = challenge.format();
+        self.0
+            .verify_with_context(&challenge, context, &signature.0)
     }
 }
 
@@ -67,11 +112,14 @@ impl SigningKey {
             .map(Into::into)
     }
 
-    pub fn sign_challenge(&self, nonce: i32, context: &[u8]) -> Result<Signature, Error> {
-        self.sign_message(
-            &format_challenge(nonce, &self.public_key().to_bytes()),
-            context,
-        )
+    pub fn sign_challenge(
+        &self,
+        challenge: &AuthChallenge,
+        context: &[u8],
+    ) -> Result<Signature, Error> {
+        let challenge = challenge.format();
+
+        self.sign_message(&challenge, context)
     }
 }
 
@@ -132,6 +180,8 @@ impl TryFrom<&'_ [u8]> for Signature {
 mod tests {
     use ml_dsa::{KeyGen, MlDsa87, signature::Keypair as _};
 
+    use crate::authn::AuthChallenge;
+
     use super::{CLIENT_CONTEXT, PublicKey, Signature, SigningKey, USERAGENT_CONTEXT};
 
     #[test]
@@ -161,13 +211,13 @@ mod tests {
     fn challenge_verification_uses_context_and_canonical_key_bytes() {
         let key = SigningKey::generate();
         let public_key = key.public_key();
-        let nonce = 17;
+        let challenge = AuthChallenge::generate(&mut rand::rng());
         let signature = key
-            .sign_challenge(nonce, CLIENT_CONTEXT)
+            .sign_challenge(&challenge, CLIENT_CONTEXT)
             .expect("signature should be created");
 
-        assert!(public_key.verify(nonce, CLIENT_CONTEXT, &signature));
-        assert!(!public_key.verify(nonce, USERAGENT_CONTEXT, &signature));
+        assert!(public_key.verify(&challenge, CLIENT_CONTEXT, &signature));
+        assert!(!public_key.verify(&challenge, USERAGENT_CONTEXT, &signature));
     }
 
     #[test]
@@ -177,10 +227,16 @@ mod tests {
 
         assert_eq!(restored.public_key(), original.public_key());
 
+        let challenge = AuthChallenge::generate(&mut rand::rng());
+
         let signature = restored
-            .sign_challenge(9, CLIENT_CONTEXT)
+            .sign_challenge(&challenge, CLIENT_CONTEXT)
             .expect("signature should be created");
 
-        assert!(restored.public_key().verify(9, CLIENT_CONTEXT, &signature));
+        assert!(
+            restored
+                .public_key()
+                .verify(&challenge, CLIENT_CONTEXT, &signature)
+        );
     }
 }

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

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

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

@@ -58,6 +58,7 @@
 use std::marker::PhantomData;
 
 use async_trait::async_trait;
+use kameo::{error::Infallible, prelude::*};
 
 /// Errors returned by transport adapters implementing [`Bi`].
 #[derive(thiserror::Error, Debug)]
@@ -106,6 +107,36 @@ 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 +192,29 @@ 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-server/Cargo.toml

@@ -58,6 +58,7 @@ 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"

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

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

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

@@ -7,7 +7,7 @@ use kameo::{Actor, actor::ActorRef, messages};
 use rand::{SeedableRng, rng, rngs::StdRng};
 
 use crate::{
-    actors::keyholder::{CreateNew, Decrypt, KeyHolder},
+    actors::vault::{CreateNew, Decrypt, Vault},
     crypto::integrity,
     db::{
         DatabaseError, DatabasePool,
@@ -34,11 +34,11 @@ pub enum SignTransactionError {
     #[error("Database error: {0}")]
     Database(#[from] DatabaseError),
 
-    #[error("Keyholder error: {0}")]
-    Keyholder(#[from] crate::actors::keyholder::Error),
+    #[error("Vault error: {0}")]
+    Vault(#[from] crate::actors::vault::Error),
 
-    #[error("Keyholder mailbox error")]
-    KeyholderSend,
+    #[error("Vault mailbox error")]
+    VaultSend,
 
     #[error("Signing error: {0}")]
     Signing(#[from] alloy::signers::Error),
@@ -49,11 +49,11 @@ pub enum SignTransactionError {
 
 #[derive(Debug, thiserror::Error)]
 pub enum Error {
-    #[error("Keyholder error: {0}")]
-    Keyholder(#[from] crate::actors::keyholder::Error),
+    #[error("Vault error: {0}")]
+    Vault(#[from] crate::actors::vault::Error),
 
-    #[error("Keyholder mailbox error")]
-    KeyholderSend,
+    #[error("Vault mailbox error")]
+    VaultSend,
 
     #[error("Database error: {0}")]
     Database(#[from] DatabaseError),
@@ -64,20 +64,20 @@ pub enum Error {
 
 #[derive(Actor)]
 pub struct EvmActor {
-    pub keyholder: ActorRef<KeyHolder>,
+    pub vault: ActorRef<Vault>,
     pub db: DatabasePool,
     pub rng: StdRng,
     pub engine: evm::Engine,
 }
 
 impl EvmActor {
-    pub fn new(keyholder: ActorRef<KeyHolder>, db: DatabasePool) -> Self {
+    pub fn new(vault: ActorRef<Vault>, db: DatabasePool) -> Self {
         // is it safe to seed rng from system once?
         // todo: audit
         let rng = StdRng::from_rng(&mut rng());
-        let engine = evm::Engine::new(db.clone(), keyholder.clone());
+        let engine = evm::Engine::new(db.clone(), vault.clone());
         Self {
-            keyholder,
+            vault,
             db,
             rng,
             engine,
@@ -94,10 +94,10 @@ impl EvmActor {
         let plaintext = key_cell.read_inline(|reader| SafeCell::new(reader.to_vec()));
 
         let aead_id: i32 = self
-            .keyholder
+            .vault
             .ask(CreateNew { plaintext })
             .await
-            .map_err(|_| Error::KeyholderSend)?;
+            .map_err(|_| Error::VaultSend)?;
 
         let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
         let wallet_id = insert_into(schema::evm_wallet::table)
@@ -160,7 +160,7 @@ impl EvmActor {
     #[message]
     pub async fn useragent_delete_grant(&mut self, _grant_id: i32) -> Result<(), Error> {
         // let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
-        // let keyholder = self.keyholder.clone();
+        // let vault = self.vault.clone();
 
         // diesel_async::AsyncConnection::transaction(&mut conn, |conn| {
         //     Box::pin(async move {
@@ -254,12 +254,12 @@ impl EvmActor {
         drop(conn);
 
         let raw_key: SafeCell<Vec<u8>> = self
-            .keyholder
+            .vault
             .ask(Decrypt {
                 aead_id: wallet.aead_encrypted_id,
             })
             .await
-            .map_err(|_| SignTransactionError::KeyholderSend)?;
+            .map_err(|_| SignTransactionError::VaultSend)?;
 
         let signer = safe_signer::SafeSigner::from_cell(raw_key)?;
 

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

@@ -6,10 +6,12 @@ use kameo::{
     reply::ReplySender,
 };
 
-use crate::actors::{
-    client::ClientProfile,
-    flow_coordinator::ApprovalError,
-    user_agent::{UserAgentSession, session::BeginNewClientApproval},
+use crate::{
+    actors::flow_coordinator::ApprovalError,
+    peers::{
+        client::ClientProfile,
+        user_agent::{UserAgentSession, session::BeginNewClientApproval},
+    },
 };
 
 pub struct Args {

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

@@ -9,18 +9,28 @@ use kameo::{
 };
 use tracing::info;
 
-use crate::actors::{
-    client::{ClientProfile, session::ClientSession},
-    flow_coordinator::client_connect_approval::ClientApprovalController,
-    user_agent::session::UserAgentSession,
+use crate::{
+    actors::{
+        flow_coordinator::client_connect_approval::ClientApprovalController,
+        useragent_registry::{GetConnected, UserAgentRegistry},
+    },
+    peers::client::{ClientProfile, session::ClientSession},
 };
 
 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 +48,7 @@ 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 +73,6 @@ 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 +94,14 @@ impl FlowCoordinator {
             unreachable!("Expected `request_client_approval` to have callback channel");
         };
 
-        let refs: Vec<_> = self.user_agents.values().cloned().collect();
+        let refs = match self.useragent_registry.ask(GetConnected).await {
+            Ok(refs) => refs,
+            Err(_) => {
+                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 +1,62 @@
 use kameo::actor::{ActorRef, Spawn};
+use kameo_actors::{DeliveryStrategy, message_bus::MessageBus};
 use thiserror::Error;
 
 use crate::{
     actors::{
-        bootstrap::Bootstrapper, evm::EvmActor, flow_coordinator::FlowCoordinator,
-        keyholder::KeyHolder,
+        bootstrap::Bootstrapper,
+        evm::EvmActor,
+        flow_coordinator::FlowCoordinator,
+        useragent_registry::UserAgentRegistry,
+        vault::Vault,
     },
     db,
 };
 
 pub mod bootstrap;
-pub mod client;
-mod evm;
+pub mod evm;
 pub mod flow_coordinator;
-pub mod keyholder;
-pub mod user_agent;
+pub mod vault;
+pub mod useragent_registry;
 
 #[derive(Error, Debug)]
 pub enum SpawnError {
     #[error("Failed to spawn Bootstrapper actor")]
     Bootstrapper(#[from] bootstrap::Error),
 
-    #[error("Failed to spawn KeyHolder actor")]
-    KeyHolder(#[from] keyholder::Error),
+    #[error("Failed to spawn Vault actor")]
+    Vault(#[from] vault::Error),
 }
 
 /// Long-lived actors that are shared across all connections and handle global state and operations
 #[derive(Clone)]
 pub struct GlobalActors {
-    pub key_holder: ActorRef<KeyHolder>,
+    pub vault: ActorRef<Vault>,
     pub bootstrapper: ActorRef<Bootstrapper>,
     pub flow_coordinator: ActorRef<FlowCoordinator>,
+    pub useragent_registry: ActorRef<UserAgentRegistry>,
     pub evm: ActorRef<EvmActor>,
+    pub events: ActorRef<MessageBus>,
 }
 
 impl GlobalActors {
+    pub fn spawn_message_bus() -> ActorRef<MessageBus> {
+        MessageBus::spawn(MessageBus::new(DeliveryStrategy::Guaranteed))
+    }
+
     pub async fn spawn(db: db::DatabasePool) -> Result<Self, SpawnError> {
-        let key_holder = KeyHolder::spawn(KeyHolder::new(db.clone()).await?);
+        let message_bus = Self::spawn_message_bus();
+        let key_holder = Vault::spawn(Vault::new(db.clone(), message_bus.clone()).await?);
+        let useragent_registry = UserAgentRegistry::spawn(UserAgentRegistry::default());
         Ok(Self {
             bootstrapper: Bootstrapper::spawn(Bootstrapper::new(&db).await?),
             evm: EvmActor::spawn(EvmActor::new(key_holder.clone(), db)),
-            key_holder,
-            flow_coordinator: FlowCoordinator::spawn(FlowCoordinator::default()),
+            vault: key_holder,
+            flow_coordinator: FlowCoordinator::spawn(FlowCoordinator::new(
+                useragent_registry.clone(),
+            )),
+            useragent_registry,
+            events: message_bus,
         })
     }
 }

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

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

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

@@ -1,55 +0,0 @@
-use crate::{
-    actors::{GlobalActors, client::ClientProfile},
-    crypto::integrity::Integrable,
-    db,
-};
-use arbiter_crypto::authn;
-
-#[derive(Debug)]
-pub struct UserAgentCredentials {
-    pub pubkey: authn::PublicKey,
-    pub nonce: i32,
-}
-
-impl Integrable for UserAgentCredentials {
-    const KIND: &'static str = "useragent_credentials";
-}
-
-// Messages, sent by user agent to connection client without having a request
-#[derive(Debug)]
-pub enum OutOfBand {
-    ClientConnectionRequest { profile: ClientProfile },
-    ClientConnectionCancel { pubkey: authn::PublicKey },
-}
-
-pub struct UserAgentConnection {
-    pub(crate) db: db::DatabasePool,
-    pub(crate) actors: GlobalActors,
-}
-
-impl UserAgentConnection {
-    pub fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
-        Self { db, actors }
-    }
-}
-
-pub mod auth;
-pub mod session;
-
-pub use auth::authenticate;
-pub use session::UserAgentSession;
-
-use crate::crypto::integrity::hashing::Hashable;
-
-impl Hashable for authn::PublicKey {
-    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
-        hasher.update(self.to_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/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 +1,58 @@
+use std::{collections::HashMap, ops::ControlFlow};
+
+use kameo::{
+    Actor,
+    actor::{ActorId, ActorRef},
+    error::Infallible,
+    messages,
+    prelude::{ActorStopReason, Context, WeakActorRef},
+};
+use tracing::info;
+
+use crate::peers::user_agent::UserAgentSession;
+
+#[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

@@ -5,7 +5,8 @@ use diesel::{
 };
 use diesel_async::{AsyncConnection, RunQueryDsl};
 use hmac::Mac as _;
-use kameo::{Actor, Reply, messages};
+use kameo::{Actor, Reply, actor::ActorRef, messages};
+use kameo_actors::message_bus::{MessageBus, Publish};
 use strum::{EnumDiscriminants, IntoDiscriminant};
 use tracing::{error, info};
 
@@ -21,26 +22,26 @@ use crate::db::{
 };
 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,
-    },
+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,
 
@@ -60,18 +61,35 @@ pub enum Error {
     BrokenDatabase,
 }
 
+struct Unsealed {
+    root_key_history_id: i32,
+    root_key: KeyCell,
+}
+
+#[derive(Default, EnumDiscriminants)]
+#[strum_discriminants(derive(Reply), vis(pub), name(VaultState))]
+enum State {
+    #[default]
+    Unbootstrapped,
+    Sealed {
+        root_key_history_id: i32,
+    },
+    Unsealed(Unsealed),
+}
+
 /// Manages vault root key and tracks current state of the vault (bootstrapped/unbootstrapped, sealed/unsealed).
 /// Provides API for encrypting and decrypting data using the vault root key.
 /// Abstraction over database to make sure nonces are never reused and encryption keys are never exposed in plaintext outside of this actor.
 #[derive(Actor)]
-pub struct KeyHolder {
+pub struct Vault {
     db: db::DatabasePool,
     state: State,
+    events: ActorRef<MessageBus>,
 }
 
 #[messages]
-impl KeyHolder {
-    pub async fn new(db: db::DatabasePool) -> Result<Self, Error> {
+impl Vault {
+    pub async fn new(db: db::DatabasePool, events: ActorRef<MessageBus>) -> Result<Self, Error> {
         let state = {
             let mut conn = db.get().await?;
 
@@ -89,10 +107,10 @@ 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?;
@@ -129,6 +147,14 @@ impl KeyHolder {
         Ok(nonce)
     }
 
+    fn expect_unsealed(state: &mut State) -> Result<&mut Unsealed, Error> {
+        match state {
+            State::Unsealed(unsealed) => Ok(unsealed),
+            State::Unbootstrapped => Err(Error::NotBootstrapped),
+            State::Sealed { .. } => Err(Error::Sealed),
+        }
+    }
+
     #[message]
     pub async fn bootstrap(&mut self, seal_key_raw: SafeCell<Vec<u8>>) -> Result<(), Error> {
         if !matches!(self.state, State::Unbootstrapped) {
@@ -181,12 +207,13 @@ 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");
+        self.events.tell(Publish(events::Bootstrapped)).await;
 
         Ok(())
     }
@@ -233,24 +260,23 @@ 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");
+        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?;
@@ -278,14 +304,10 @@ impl KeyHolder {
     // Creates new `aead_encrypted` entry in the database and returns it's ID
     #[message]
     pub async fn create_new(&mut self, mut plaintext: SafeCell<Vec<u8>>) -> Result<i32, Error> {
-        let State::Unsealed {
+        let Unsealed {
             root_key,
             root_key_history_id,
-            ..
-        } = &mut self.state
-        else {
-            return Err(Error::NotBootstrapped);
-        };
+        } = Self::expect_unsealed(&mut self.state)?;
 
         // Order matters here - `get_new_nonce` acquires connection, so we need to call it before next acquire
         // Borrow checker note: &mut borrow a few lines above is disjoint from this field
@@ -315,19 +337,16 @@ impl KeyHolder {
     }
 
     #[message]
-    pub fn get_state(&self) -> KeyHolderState {
+    pub fn get_state(&self) -> VaultState {
         self.state.discriminant()
     }
 
     #[message]
     pub fn sign_integrity(&mut self, mac_input: Vec<u8>) -> Result<(i32, Vec<u8>), Error> {
-        let State::Unsealed {
+        let Unsealed {
             root_key,
             root_key_history_id,
-        } = &mut self.state
-        else {
-            return Err(Error::NotBootstrapped);
-        };
+        } = Self::expect_unsealed(&mut self.state)?;
 
         let mut hmac = root_key
             .0
@@ -349,13 +368,10 @@ impl KeyHolder {
         expected_mac: Vec<u8>,
         key_version: i32,
     ) -> Result<bool, Error> {
-        let State::Unsealed {
+        let Unsealed {
             root_key,
             root_key_history_id,
-        } = &mut self.state
-        else {
-            return Err(Error::NotBootstrapped);
-        };
+        } = Self::expect_unsealed(&mut self.state)?;
 
         if *root_key_history_id != key_version {
             return Ok(false);
@@ -374,17 +390,16 @@ 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,
         };
+        self.events.tell(Publish(events::VaultResealed)).await;
         Ok(())
     }
 }
@@ -395,13 +410,18 @@ mod tests {
 
     use diesel_async::RunQueryDsl;
 
-    use crate::db::{self};
+    use crate::{
+        actors::GlobalActors,
+        db::{self},
+    };
     use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 
     use super::*;
 
-    async fn bootstrapped_actor(db: &db::DatabasePool) -> KeyHolder {
-        let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    async fn bootstrapped_actor(db: &db::DatabasePool) -> Vault {
+        let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+            .await
+            .unwrap();
         let seal_key = SafeCell::new(b"test-seal-key".to_vec());
         actor.bootstrap(seal_key).await.unwrap();
         actor
@@ -413,17 +433,17 @@ 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/crypto/integrity/v1.rs

@@ -1,6 +1,8 @@
-use crate::{actors::keyholder, crypto::integrity::hashing::Hashable};
-use arbiter_crypto::safecell::SafeCellHandle as _;
-use hmac::{Hmac, Mac as _};
+use crate::{
+    actors::vault::{self, GetState},
+    crypto::integrity::hashing::Hashable,
+};
+use hmac::Hmac;
 use sha2::Sha256;
 
 use diesel::{ExpressionMethods as _, QueryDsl, dsl::insert_into, sqlite::Sqlite};
@@ -11,7 +13,7 @@ use sha2::Digest as _;
 pub mod hashing;
 
 use crate::{
-    actors::keyholder::{KeyHolder, SignIntegrity, VerifyIntegrity},
+    actors::vault::{SignIntegrity, Vault, VerifyIntegrity},
     db::{
         self,
         models::{IntegrityEnvelope, NewIntegrityEnvelope},
@@ -24,11 +26,11 @@ 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 },
@@ -105,7 +107,7 @@ impl IntoId for &'_ [u8] {
 
 pub async fn sign_entity<E: Integrable>(
     conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
     entity: &E,
     entity_id: impl IntoId,
 ) -> Result<(), Error> {
@@ -115,13 +117,14 @@ pub async fn sign_entity<E: Integrable>(
 
     let mac_input = build_mac_input(E::KIND, &entity_id, E::VERSION, &payload_hash);
 
-    let (key_version, mac) = keyholder
-        .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 {
+                kameo::error::SendError::HandlerError(inner) => Error::Vault(inner),
+                _ => Error::VaultSend,
+            })?;
 
     insert_into(integrity_envelope::table)
         .values(NewIntegrityEnvelope {
@@ -150,7 +153,7 @@ pub async fn sign_entity<E: Integrable>(
 
 pub async fn verify_entity<E: Integrable>(
     conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
     entity: &E,
     entity_id: impl IntoId,
 ) -> Result<AttestationStatus, Error> {
@@ -178,7 +181,7 @@ pub async fn verify_entity<E: Integrable>(
     let payload_hash = payload_hash(&entity);
     let mac_input = build_mac_input(E::KIND, &entity_id, envelope.payload_version, &payload_hash);
 
-    let result = keyholder
+    let result = vault
         .ask(VerifyIntegrity {
             mac_input,
             expected_mac: envelope.mac,
@@ -191,31 +194,37 @@ pub async fn verify_entity<E: Integrable>(
         Ok(false) => Err(Error::MacMismatch {
             entity_kind: E::KIND,
         }),
-        Err(SendError::HandlerError(keyholder::Error::NotBootstrapped)) => {
+        Err(SendError::HandlerError(vault::Error::Sealed)) => {
             Ok(AttestationStatus::Unavailable)
         }
-        Err(_) => Err(Error::KeyholderSend),
+        Err(_) => Err(Error::VaultSend),
     }
 }
 
+pub async fn is_signing_available(vault: &ActorRef<Vault>) -> Result<bool, Error> {
+    let state = vault.ask(GetState).await.map_err(|_| Error::VaultSend)?;
+    Ok(matches!(state, vault::VaultState::Unsealed))
+}
+
 #[cfg(test)]
 mod tests {
     use diesel::{ExpressionMethods as _, QueryDsl};
     use diesel_async::RunQueryDsl;
     use kameo::{actor::ActorRef, prelude::Spawn};
-    
+
     use sha2::Digest;
 
-    
-
     use crate::{
-        actors::keyholder::{Bootstrap, KeyHolder},
+        actors::{
+            GlobalActors,
+            vault::{Bootstrap, Vault},
+        },
         db::{self, schema},
     };
     use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 
-    use super::{Error, Integrable, sign_entity, verify_entity};
     use super::hashing::Hashable;
+    use super::{Error, Integrable, sign_entity, verify_entity};
 
     #[derive(Clone)]
     struct DummyEntity {
@@ -233,8 +242,12 @@ mod tests {
         const KIND: &'static str = "dummy_entity";
     }
 
-    async fn bootstrapped_keyholder(db: &db::DatabasePool) -> ActorRef<KeyHolder> {
-        let actor = KeyHolder::spawn(KeyHolder::new(db.clone()).await.unwrap());
+    async fn bootstrapped_vault(db: &db::DatabasePool) -> ActorRef<Vault> {
+        let actor = Vault::spawn(
+            Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+                .await
+                .unwrap(),
+        );
         actor
             .ask(Bootstrap {
                 seal_key_raw: SafeCell::new(b"integrity-test-seal-key".to_vec()),
@@ -247,7 +260,7 @@ mod tests {
     #[tokio::test]
     async fn sign_writes_envelope_and_verify_passes() {
         let db = db::create_test_pool().await;
-        let keyholder = bootstrapped_keyholder(&db).await;
+        let vault = bootstrapped_vault(&db).await;
         let mut conn = db.get().await.unwrap();
 
         const ENTITY_ID: &[u8] = b"entity-id-7";
@@ -257,7 +270,7 @@ mod tests {
             payload: b"payload-v1".to_vec(),
         };
 
-        sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
             .await
             .unwrap();
 
@@ -270,7 +283,7 @@ mod tests {
             .unwrap();
 
         assert_eq!(count, 1, "envelope row must be created exactly once");
-        verify_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        verify_entity(&mut conn, &vault, &entity, ENTITY_ID)
             .await
             .unwrap();
     }
@@ -278,7 +291,7 @@ mod tests {
     #[tokio::test]
     async fn tampered_mac_fails_verification() {
         let db = db::create_test_pool().await;
-        let keyholder = bootstrapped_keyholder(&db).await;
+        let vault = bootstrapped_vault(&db).await;
         let mut conn = db.get().await.unwrap();
 
         const ENTITY_ID: &[u8] = b"entity-id-11";
@@ -288,7 +301,7 @@ mod tests {
             payload: b"payload-v1".to_vec(),
         };
 
-        sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
             .await
             .unwrap();
 
@@ -300,7 +313,7 @@ mod tests {
             .await
             .unwrap();
 
-        let err = verify_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        let err = verify_entity(&mut conn, &vault, &entity, ENTITY_ID)
             .await
             .unwrap_err();
         assert!(matches!(err, Error::MacMismatch { .. }));
@@ -309,7 +322,7 @@ mod tests {
     #[tokio::test]
     async fn changed_payload_fails_verification() {
         let db = db::create_test_pool().await;
-        let keyholder = bootstrapped_keyholder(&db).await;
+        let vault = bootstrapped_vault(&db).await;
         let mut conn = db.get().await.unwrap();
 
         const ENTITY_ID: &[u8] = b"entity-id-21";
@@ -319,7 +332,7 @@ mod tests {
             payload: b"payload-v1".to_vec(),
         };
 
-        sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
             .await
             .unwrap();
 
@@ -328,7 +341,7 @@ mod tests {
             ..entity
         };
 
-        let err = verify_entity(&mut conn, &keyholder, &tampered, ENTITY_ID)
+        let err = verify_entity(&mut conn, &vault, &tampered, ENTITY_ID)
             .await
             .unwrap_err();
         assert!(matches!(err, Error::MacMismatch { .. }));

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

@@ -195,7 +195,6 @@ pub struct ProgramClientMetadataHistory {
 #[diesel(table_name = schema::program_client, check_for_backend(Sqlite))]
 pub struct ProgramClient {
     pub id: i32,
-    pub nonce: i32,
     pub public_key: Vec<u8>,
     pub metadata_id: i32,
     pub created_at: SqliteTimestamp,
@@ -206,7 +205,6 @@ pub struct ProgramClient {
 #[diesel(table_name = schema::useragent_client, check_for_backend(Sqlite))]
 pub struct UseragentClient {
     pub id: i32,
-    pub nonce: i32,
     pub public_key: Vec<u8>,
     pub created_at: SqliteTimestamp,
     pub updated_at: SqliteTimestamp,

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/mod.rs

@@ -11,7 +11,7 @@ use diesel_async::{AsyncConnection, RunQueryDsl};
 use kameo::actor::ActorRef;
 
 use crate::{
-    actors::keyholder::KeyHolder,
+    actors::vault::Vault,
     crypto::integrity,
     db::{
         self, DatabaseError,
@@ -138,7 +138,7 @@ async fn check_shared_constraints(
 // Supporting only EIP-1559 transactions for now, but we can easily extend this to support legacy transactions if needed
 pub struct Engine {
     db: db::DatabasePool,
-    keyholder: ActorRef<KeyHolder>,
+    vault: ActorRef<Vault>,
 }
 
 impl Engine {
@@ -158,7 +158,7 @@ impl Engine {
             .map_err(DatabaseError::from)?
             .ok_or(PolicyError::NoMatchingGrant)?;
 
-        integrity::verify_entity(&mut conn, &self.keyholder, &grant.settings, grant.id).await?;
+        integrity::verify_entity(&mut conn, &self.vault, &grant.settings, grant.id).await?;
 
         let mut violations = check_shared_constraints(
             &context,
@@ -207,8 +207,8 @@ impl Engine {
 }
 
 impl Engine {
-    pub fn new(db: db::DatabasePool, keyholder: ActorRef<KeyHolder>) -> Self {
-        Self { db, keyholder }
+    pub fn new(db: db::DatabasePool, vault: ActorRef<Vault>) -> Self {
+        Self { db, vault }
     }
 
     pub async fn create_grant<P: Policy>(
@@ -219,7 +219,7 @@ impl Engine {
         P::Settings: Clone,
     {
         let mut conn = self.db.get().await?;
-        let keyholder = self.keyholder.clone();
+        let vault = self.vault.clone();
 
         let id = conn
             .transaction(|conn| {
@@ -258,7 +258,7 @@ impl Engine {
 
                     P::create_grant(&basic_grant, &full_grant.specific, conn).await?;
 
-                    integrity::sign_entity(conn, &keyholder, &full_grant, basic_grant.id)
+                    integrity::sign_entity(conn, &vault, &full_grant, basic_grant.id)
                         .await
                         .map_err(|_| diesel::result::Error::RollbackTransaction)?;
 
@@ -283,7 +283,7 @@ impl Engine {
 
         // Verify integrity of all grants before returning any results
         for grant in &all_grants {
-            integrity::verify_entity(conn, &self.keyholder, &grant.settings, grant.id).await?;
+            integrity::verify_entity(conn, &self.vault, &grant.settings, grant.id).await?;
         }
 
         Ok(all_grants.into_iter().map(|g| Grant {

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

@@ -10,8 +10,8 @@ use tonic::Status;
 use tracing::{info, warn};
 
 use crate::{
-    actors::client::{ClientConnection, session::ClientSession},
     grpc::request_tracker::RequestTracker,
+    peers::client::{ClientConnection, session::ClientSession},
 };
 
 mod auth;

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

@@ -22,8 +22,8 @@ use tonic::Status;
 use tracing::warn;
 
 use crate::{
-    actors::client::{self, ClientConnection, auth},
     grpc::request_tracker::RequestTracker,
+    peers::client::{self, ClientConnection, auth},
 };
 
 pub struct AuthTransportAdapter<'a> {
@@ -44,10 +44,14 @@ impl<'a> AuthTransportAdapter<'a> {
 
     fn response_to_proto(response: auth::Outbound) -> AuthResponsePayload {
         match response {
-            auth::Outbound::AuthChallenge { pubkey, nonce } => {
+            auth::Outbound::AuthChallenge {  challenge } => {
                 AuthResponsePayload::Challenge(ProtoAuthChallenge {
-                    pubkey: pubkey.to_bytes(),
-                    nonce,
+                    timestamp_nanos: challenge
+                        .timestamp
+                        .timestamp_nanos_opt()
+                        .expect("timestamp within range")
+                        as u64,
+                    random: challenge.nonce.to_vec(),
                 })
             }
             auth::Outbound::AuthSuccess => {

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

@@ -16,11 +16,11 @@ use tonic::Status;
 use tracing::warn;
 
 use crate::{
-    actors::client::session::{ClientSession, HandleSignTransaction, SignTransactionRpcError},
     grpc::{
         Convert, TryConvert,
         common::inbound::{RawEvmAddress, RawEvmTransaction},
     },
+    peers::client::session::{ClientSession, HandleSignTransaction, SignTransactionRpcError},
 };
 
 fn wrap_response(payload: EvmResponsePayload) -> ClientResponsePayload {

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

@@ -12,9 +12,9 @@ use kameo::{actor::ActorRef, error::SendError};
 use tonic::Status;
 use tracing::warn;
 
-use crate::actors::{
-    client::session::{ClientSession, Error, HandleQueryVaultState},
-    keyholder::KeyHolderState,
+use crate::{
+    actors::vault::VaultState,
+    peers::client::session::{ClientSession, Error, HandleQueryVaultState},
 };
 
 pub(super) async fn dispatch(
@@ -30,9 +30,9 @@ pub(super) async fn dispatch(
     match payload {
         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/mod.rs

@@ -10,8 +10,7 @@ use tonic::{Request, Response, Status, async_trait};
 use tracing::info;
 
 use crate::{
-    actors::{client::ClientConnection, user_agent::UserAgentConnection},
-    grpc::user_agent::start,
+    peers::{client::ClientConnection, user_agent::UserAgentConnection},
 };
 
 mod request_tracker;
@@ -63,7 +62,7 @@ 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/user_agent.rs

@@ -9,13 +9,13 @@ 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 tonic::Status;
 use tracing::{error, info, warn};
 
 use crate::{
-    actors::user_agent::{OutOfBand, UserAgentConnection, UserAgentSession},
     grpc::request_tracker::RequestTracker,
+    peers::user_agent::{OutOfBand, UserAgentConnection, UserAgentSession},
 };
 
 mod auth;
@@ -24,6 +24,7 @@ mod inbound;
 mod outbound;
 mod sdk_client;
 mod vault;
+mod vault_gate;
 
 pub struct OutOfBandAdapter(mpsc::Sender<OutOfBand>);
 
@@ -124,21 +125,23 @@ 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

@@ -18,13 +18,13 @@ use tonic::Status;
 use tracing::warn;
 
 use crate::{
-    actors::user_agent::{UserAgentConnection, auth},
     grpc::request_tracker::RequestTracker,
+    peers::user_agent::{Credentials, UserAgentConnection, auth},
 };
 
 pub struct AuthTransportAdapter<'a> {
-    bi: &'a mut GrpcBi<UserAgentRequest, UserAgentResponse>,
-    request_tracker: &'a mut RequestTracker,
+    pub(super) bi: &'a mut GrpcBi<UserAgentRequest, UserAgentResponse>,
+    pub(super) request_tracker: &'a mut RequestTracker,
 }
 
 impl<'a> AuthTransportAdapter<'a> {
@@ -38,19 +38,35 @@ impl<'a> AuthTransportAdapter<'a> {
         }
     }
 
-    async fn send_user_agent_response(
+    pub(super) fn bi_mut(&mut self) -> &mut GrpcBi<UserAgentRequest, UserAgentResponse> {
+        self.bi
+    }
+
+    pub(super) 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]
@@ -61,8 +77,15 @@ impl Sender<Result<auth::Outbound, auth::Error>> for AuthTransportAdapter<'_> {
     ) -> Result<(), TransportError> {
         use auth::{Error, Outbound};
         let payload = match item {
-            Ok(Outbound::AuthChallenge { nonce }) => {
-                AuthResponsePayload::Challenge(ProtoAuthChallenge { nonce })
+            Ok(Outbound::AuthChallenge { challenge }) => {
+                AuthResponsePayload::Challenge(ProtoAuthChallenge {
+                    timestamp_nanos: challenge
+                        .timestamp
+                        .timestamp_nanos_opt()
+                        .expect("timestamp within range")
+                        as u64,
+                    random: challenge.nonce.to_vec(),
+                })
             }
             Ok(Outbound::AuthSuccess) => {
                 AuthResponsePayload::Result(ProtoAuthResult::Success.into())
@@ -140,7 +163,6 @@ impl Receiver<auth::Inbound> for AuthTransportAdapter<'_> {
             AuthRequestPayload::ChallengeRequest(ProtoAuthChallengeRequest {
                 pubkey,
                 bootstrap_token,
-                key_type: _,
             }) => {
                 let Ok(pubkey) = authn::PublicKey::try_from(pubkey.as_slice()) else {
                     warn!(
@@ -168,7 +190,7 @@ pub async fn start(
     conn: &mut UserAgentConnection,
     bi: &mut GrpcBi<UserAgentRequest, UserAgentResponse>,
     request_tracker: &mut RequestTracker,
-) -> Result<authn::PublicKey, auth::Error> {
-    let transport = AuthTransportAdapter::new(bi, request_tracker);
-    auth::authenticate(conn, transport).await
+) -> Result<Credentials, auth::Error> {
+    let mut transport = AuthTransportAdapter::new(bi, request_tracker);
+    auth::authenticate(conn, &mut transport).await
 }

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

@@ -23,18 +23,18 @@ use tonic::Status;
 use tracing::warn;
 
 use crate::{
-    actors::user_agent::{
+    grpc::{
+        Convert, TryConvert,
+        common::inbound::{RawEvmAddress, RawEvmTransaction},
+    },
+    peers::user_agent::{
         UserAgentSession,
-        session::connection::{
+        session::handlers::{
             GrantMutationError, HandleEvmWalletCreate, HandleEvmWalletList, HandleGrantCreate,
             HandleGrantDelete, HandleGrantList, HandleSignTransaction,
             SignTransactionError as SessionSignTransactionError,
         },
     },
-    grpc::{
-        Convert, TryConvert,
-        common::inbound::{RawEvmAddress, RawEvmTransaction},
-    },
 };
 
 fn wrap_evm_response(payload: EvmResponsePayload) -> UserAgentResponsePayload {

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

@@ -21,15 +21,15 @@ use tonic::Status;
 use tracing::{info, warn};
 
 use crate::{
-    actors::user_agent::{
+    db::models::NewEvmWalletAccess,
+    grpc::Convert,
+    peers::user_agent::{
         OutOfBand, UserAgentSession,
-        session::connection::{
+        session::handlers::{
             HandleGrantEvmWalletAccess, HandleListWalletAccess, HandleNewClientApprove,
             HandleRevokeEvmWalletAccess, HandleSdkClientList,
         },
     },
-    db::models::NewEvmWalletAccess,
-    grpc::Convert,
 };
 
 fn wrap_sdk_client_response(payload: SdkClientResponsePayload) -> UserAgentResponsePayload {

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

@@ -1,34 +1,15 @@
 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,
-        },
-    },
+    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,
-        },
-    },
+use crate::{
+    actors::vault::VaultState,
+    peers::user_agent::{UserAgentSession, session::handlers::HandleQueryVaultState},
 };
 
 fn wrap_vault_response(payload: VaultResponsePayload) -> UserAgentResponsePayload {
@@ -37,18 +18,6 @@ fn wrap_vault_response(payload: VaultResponsePayload) -> UserAgentResponsePayloa
     })
 }
 
-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,
@@ -59,116 +28,21 @@ 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::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 +1,81 @@
+use arbiter_proto::transport::{Bi, Error as TransportError, Receiver, Sender};
+use async_trait::async_trait;
+use tonic::Status;
+use tracing::warn;
+
+use super::auth::AuthTransportAdapter;
+use crate::{
+    grpc::TryConvert,
+    peers::user_agent::vault_gate::{self as vault_gate},
+};
+
+mod inbound;
+mod outbound;
+
+#[async_trait]
+impl Receiver<vault_gate::Inbound> for AuthTransportAdapter<'_> {
+    async fn recv(&mut self) -> Option<vault_gate::Inbound> {
+        loop {
+            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) => return Some(inbound),
+                Err(status) => {
+                    let _ = self.bi_mut().send(Err(status)).await;
+                    return 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 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;
+
+use crate::{
+    grpc::{Convert, TryConvert},
+    peers::user_agent::vault_gate::{
+        self as vault_gate, HandleBootstrapEncryptedKey, HandleHandshake, HandleUnsealEncryptedKey,
+    },
+};
+
+impl TryConvert for UserAgentRequestPayload {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        match self {
+            UserAgentRequestPayload::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 {
+            VaultRequestPayload::QueryState(_) => Ok(vault_gate::Inbound::HandleVaultState),
+            VaultRequestPayload::Unseal(req) => req.try_convert(),
+            VaultRequestPayload::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 {
+            UnsealRequestPayload::Start(start) => start.try_convert(),
+            UnsealRequestPayload::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 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;
+
+use crate::{
+    actors::vault::VaultState,
+    grpc::{Convert, TryConvert},
+    peers::user_agent::vault_gate::{self as vault_gate},
+};
+
+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(),
+    }))
+}
+
+impl Convert for VaultState {
+    type Output = UserAgentResponsePayload;
+
+    fn convert(self) -> UserAgentResponsePayload {
+        let proto_state = match self {
+            VaultState::Unbootstrapped => ProtoVaultState::Unbootstrapped,
+            VaultState::Sealed => ProtoVaultState::Sealed,
+            VaultState::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 {
+            vault_gate::Outbound::HandleVaultState(result) => result
+                .map_err(|err| {
+                    warn!(?err, "vault state query failed");
+                    Status::internal("Failed to query vault state")
+                })
+                .map(VaultState::convert),
+            vault_gate::Outbound::HandleHandshake(result) => result
+                .map_err(|err| {
+                    warn!(?err, "handshake failed");
+                    Status::internal("Failed to start unseal flow")
+                })
+                .map(vault_gate::HandshakeResponse::convert),
+            vault_gate::Outbound::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(),
+                )))
+            }
+            vault_gate::Outbound::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

@@ -7,6 +7,7 @@ pub mod crypto;
 pub mod db;
 pub mod evm;
 pub mod grpc;
+pub mod peers;
 pub mod utils;
 
 pub struct Server {

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

@@ -1,4 +1,4 @@
-use arbiter_crypto::authn::{self, CLIENT_CONTEXT};
+use arbiter_crypto::authn::{self, AuthChallenge, CLIENT_CONTEXT};
 use arbiter_proto::{
     ClientMetadata,
     transport::{Bi, expect_message},
@@ -14,9 +14,9 @@ use tracing::error;
 
 use crate::{
     actors::{
-        client::{ClientConnection, ClientCredentials, ClientProfile},
+        GlobalActors,
         flow_coordinator::{self, RequestClientApproval},
-        keyholder::KeyHolder,
+        vault::Vault,
     },
     crypto::integrity::{self, AttestationStatus},
     db::{
@@ -26,6 +26,8 @@ use crate::{
     },
 };
 
+use super::{ClientConnection, ClientCredentials, ClientProfile};
+
 #[derive(thiserror::Error, Debug, Clone, PartialEq, Eq)]
 pub enum Error {
     #[error("Database pool unavailable")]
@@ -72,19 +74,14 @@ pub enum Inbound {
 
 #[derive(Debug, Clone)]
 pub enum Outbound {
-    AuthChallenge {
-        pubkey: authn::PublicKey,
-        nonce: i32,
-    },
+    AuthChallenge { challenge: AuthChallenge },
     AuthSuccess,
 }
 
-/// Returns the current nonce and client ID for a registered client.
-/// Returns `None` if the pubkey is not registered.
-async fn get_current_nonce_and_id(
+async fn get_client_id(
     db: &db::DatabasePool,
     pubkey: &authn::PublicKey,
-) -> Result<Option<(i32, i32)>, Error> {
+) -> Result<Option<i32>, Error> {
     let pubkey_bytes = pubkey.to_bytes();
     let mut conn = db.get().await.map_err(|e| {
         error!(error = ?e, "Database pool error");
@@ -92,8 +89,8 @@ async fn get_current_nonce_and_id(
     })?;
     program_client::table
         .filter(program_client::public_key.eq(&pubkey_bytes))
-        .select((program_client::id, program_client::nonce))
-        .first::<(i32, i32)>(&mut conn)
+        .select(program_client::id)
+        .first::<i32>(&mut conn)
         .await
         .optional()
         .map_err(|e| {
@@ -104,7 +101,7 @@ async fn get_current_nonce_and_id(
 
 async fn verify_integrity(
     db: &db::DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
     pubkey: &authn::PublicKey,
 ) -> Result<(), Error> {
     let mut db_conn = db.get().await.map_err(|e| {
@@ -112,17 +109,16 @@ async fn verify_integrity(
         Error::DatabasePoolUnavailable
     })?;
 
-    let (id, nonce) = get_current_nonce_and_id(db, pubkey).await?.ok_or_else(|| {
+    let id = get_client_id(db, pubkey).await?.ok_or_else(|| {
         error!("Client not found during integrity verification");
         Error::DatabaseOperationFailed
     })?;
 
     let attestation = integrity::verify_entity(
         &mut db_conn,
-        keyholder,
+        vault,
         &ClientCredentials {
             pubkey: pubkey.clone(),
-            nonce,
         },
         id,
     )
@@ -140,57 +136,7 @@ async fn verify_integrity(
     Ok(())
 }
 
-/// Atomically increments the nonce and re-signs the integrity envelope.
-/// Returns the new nonce, which is used as the challenge nonce.
-async fn create_nonce(
-    db: &db::DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
-    pubkey: &authn::PublicKey,
-) -> Result<i32, Error> {
-    let pubkey_bytes = pubkey.to_bytes();
-    let pubkey = pubkey.clone();
-
-    let mut conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::DatabasePoolUnavailable
-    })?;
-
-    conn.exclusive_transaction(|conn| {
-        let keyholder = keyholder.clone();
-        let pubkey = pubkey.clone();
-        Box::pin(async move {
-            let (id, new_nonce): (i32, i32) = update(program_client::table)
-                .filter(program_client::public_key.eq(&pubkey_bytes))
-                .set(program_client::nonce.eq(program_client::nonce + 1))
-                .returning((program_client::id, program_client::nonce))
-                .get_result(conn)
-                .await?;
-
-            integrity::sign_entity(
-                conn,
-                &keyholder,
-                &ClientCredentials {
-                    pubkey: pubkey.clone(),
-                    nonce: new_nonce,
-                },
-                id,
-            )
-            .await
-            .map_err(|e| {
-                error!(?e, "Integrity sign failed after nonce update");
-                Error::DatabaseOperationFailed
-            })?;
-
-            Ok(new_nonce)
-        })
-    })
-    .await
-}
-
-async fn approve_new_client(
-    actors: &crate::actors::GlobalActors,
-    profile: ClientProfile,
-) -> Result<(), Error> {
+async fn approve_new_client(actors: &GlobalActors, profile: ClientProfile) -> Result<(), Error> {
     let result = actors
         .flow_coordinator
         .ask(RequestClientApproval { client: profile })
@@ -212,7 +158,7 @@ async fn approve_new_client(
 
 async fn insert_client(
     db: &db::DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
     pubkey: &authn::PublicKey,
     metadata: &ClientMetadata,
 ) -> Result<i32, Error> {
@@ -226,11 +172,9 @@ async fn insert_client(
     })?;
 
     conn.exclusive_transaction(|conn| {
-        let keyholder = keyholder.clone();
+        let vault = vault.clone();
         let pubkey = pubkey.clone();
         Box::pin(async move {
-            const NONCE_START: i32 = 1;
-
             let metadata_id = insert_into(client_metadata::table)
                 .values((
                     client_metadata::name.eq(&metadata.name),
@@ -245,7 +189,6 @@ async fn insert_client(
                 .values((
                     program_client::public_key.eq(pubkey.to_bytes()),
                     program_client::metadata_id.eq(metadata_id),
-                    program_client::nonce.eq(NONCE_START),
                 ))
                 .on_conflict_do_nothing()
                 .returning(program_client::id)
@@ -254,10 +197,9 @@ async fn insert_client(
 
             integrity::sign_entity(
                 conn,
-                &keyholder,
+                &vault,
                 &ClientCredentials {
                     pubkey: pubkey.clone(),
-                    nonce: NONCE_START,
                 },
                 client_id,
             )
@@ -347,15 +289,14 @@ async fn sync_client_metadata(
 async fn challenge_client<T>(
     transport: &mut T,
     pubkey: authn::PublicKey,
-    nonce: i32,
+    challenge: AuthChallenge,
 ) -> Result<(), Error>
 where
     T: Bi<Inbound, Result<Outbound, Error>> + ?Sized,
 {
     transport
         .send(Ok(Outbound::AuthChallenge {
-            pubkey: pubkey.clone(),
-            nonce,
+            challenge: challenge.clone(),
         }))
         .await
         .map_err(|e| {
@@ -373,7 +314,7 @@ where
         Error::Transport
     })?;
 
-    if !pubkey.verify(nonce, CLIENT_CONTEXT, &signature) {
+    if !pubkey.verify(&challenge, CLIENT_CONTEXT, &signature) {
         error!("Challenge solution verification failed");
         return Err(Error::InvalidChallengeSolution);
     }
@@ -389,9 +330,9 @@ where
         return Err(Error::Transport);
     };
 
-    let client_id = match get_current_nonce_and_id(&props.db, &pubkey).await? {
-        Some((id, _)) => {
-            verify_integrity(&props.db, &props.actors.key_holder, &pubkey).await?;
+    let client_id = match get_client_id(&props.db, &pubkey).await? {
+        Some(id) => {
+            verify_integrity(&props.db, &props.actors.vault, &pubkey).await?;
             id
         }
         None => {
@@ -403,13 +344,14 @@ where
                 },
             )
             .await?;
-            insert_client(&props.db, &props.actors.key_holder, &pubkey, &metadata).await?
+            insert_client(&props.db, &props.actors.vault, &pubkey, &metadata).await?
         }
     };
 
     sync_client_metadata(&props.db, client_id, &metadata).await?;
-    let challenge_nonce = create_nonce(&props.db, &props.actors.key_holder, &pubkey).await?;
-    challenge_client(transport, pubkey, challenge_nonce).await?;
+
+    let challenge = AuthChallenge::generate(&mut rand::rng());
+    challenge_client(transport, pubkey, challenge).await?;
 
     transport
         .send(Ok(Outbound::AuthSuccess))

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

@@ -4,9 +4,10 @@ use kameo::actor::Spawn;
 use tracing::{error, info};
 
 use crate::{
-    actors::{GlobalActors, client::session::ClientSession},
+    actors::GlobalActors,
     crypto::integrity::{Integrable, hashing::Hashable},
     db,
+    peers::client::session::ClientSession,
 };
 
 #[derive(Debug, Clone)]
@@ -17,7 +18,6 @@ pub struct ClientProfile {
 
 pub struct ClientCredentials {
     pub pubkey: authn::PublicKey,
-    pub nonce: i32,
 }
 
 impl Integrable for ClientCredentials {
@@ -27,7 +27,6 @@ impl Integrable for ClientCredentials {
 impl Hashable for ClientCredentials {
     fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
         hasher.update(self.pubkey.to_bytes());
-        self.nonce.hash(hasher);
     }
 }
 

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

@@ -6,15 +6,16 @@ use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
 use crate::{
     actors::{
         GlobalActors,
-        client::ClientConnection,
         evm::{ClientSignTransaction, SignTransactionError},
         flow_coordinator::RegisterClient,
-        keyholder::KeyHolderState,
+        vault::VaultState,
     },
     db,
     evm::VetError,
 };
 
+use super::ClientConnection;
+
 pub struct ClientSession {
     props: ClientConnection,
     client_id: i32,
@@ -29,13 +30,13 @@ 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);
             }
         };

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

@@ -1,14 +1,13 @@
-use arbiter_crypto::authn;
+use arbiter_crypto::authn::{self, AuthChallenge};
 use arbiter_proto::transport::Bi;
 use tracing::error;
 
-use crate::actors::user_agent::{
-    UserAgentConnection,
-    auth::state::{AuthContext, AuthStateMachine},
-};
 mod state;
 use state::*;
 
+use super::Credentials;
+use super::UserAgentConnection;
+
 #[derive(Debug, Clone)]
 pub enum Inbound {
     AuthChallengeRequest {
@@ -46,7 +45,7 @@ impl From<diesel::result::Error> for Error {
 
 #[derive(Debug, Clone)]
 pub enum Outbound {
-    AuthChallenge { nonce: i32 },
+    AuthChallenge { challenge: AuthChallenge },
     AuthSuccess,
 }
 
@@ -54,12 +53,11 @@ fn parse_auth_event(payload: Inbound) -> AuthEvents {
     match payload {
         Inbound::AuthChallengeRequest {
             pubkey,
-            bootstrap_token: None,
-        } => AuthEvents::AuthRequest(ChallengeRequest { pubkey }),
-        Inbound::AuthChallengeRequest {
+            bootstrap_token,
+        } => AuthEvents::AuthRequest(ChallengeRequest {
             pubkey,
-            bootstrap_token: Some(token),
-        } => AuthEvents::BootstrapAuthRequest(BootstrapAuthRequest { pubkey, token }),
+            bootstrap_token,
+        }),
         Inbound::AuthChallengeSolution { signature } => {
             AuthEvents::ReceivedSolution(ChallengeSolution {
                 solution: signature,
@@ -70,21 +68,20 @@ fn parse_auth_event(payload: Inbound) -> AuthEvents {
 
 pub async fn authenticate<T>(
     props: &mut UserAgentConnection,
-    transport: T,
-) -> Result<authn::PublicKey, Error>
+    transport: &mut T,
+) -> Result<Credentials, Error>
 where
-    T: Bi<Inbound, Result<Outbound, Error>> + Send,
+    T: Bi<Inbound, Result<Outbound, Error>> + Send + ?Sized,
 {
     let mut state = AuthStateMachine::new(AuthContext::new(props, transport));
 
     loop {
-        // `state` holds a mutable reference to `props` so we can't access it directly here
         let Some(payload) = state.context_mut().transport.recv().await else {
             return Err(Error::Transport);
         };
 
         match state.process_event(parse_auth_event(payload)).await {
-            Ok(AuthStates::AuthOk(key)) => return Ok(key.clone()),
+            Ok(AuthStates::AuthOk(result)) => return Ok(result.clone()),
             Err(AuthError::ActionFailed(err)) => {
                 error!(?err, "State machine action failed");
                 return Err(err);

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

@@ -0,0 +1,196 @@
+use super::super::{Credentials, UserAgentConnection};
+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;
+
+use super::Error;
+use crate::{
+    actors::bootstrap::ConsumeToken,
+    db::{DatabasePool, schema::useragent_client},
+    peers::user_agent::auth::Outbound,
+};
+
+pub struct ChallengeRequest {
+    pub pubkey: authn::PublicKey,
+    pub bootstrap_token: Option<String>,
+}
+
+pub struct ChallengeContext {
+    pub challenge: AuthChallenge,
+    pub pubkey: authn::PublicKey,
+    pub bootstrap_token: Option<String>,
+}
+
+pub struct ChallengeSolution {
+    pub 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 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 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<super::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 +1,199 @@
+use crate::{
+    actors::{
+        GlobalActors,
+        vault::{GetState, Vault},
+    },
+    crypto::integrity::{self, AttestationStatus, Integrable},
+    db::{self, DatabaseError, DatabasePool},
+    peers::client::ClientProfile,
+};
+use arbiter_crypto::authn;
+
+use arbiter_proto::transport::{Bi, Sender};
+pub use auth::authenticate;
+use kameo::actor::{ActorRef, Spawn as _};
+pub use session::UserAgentSession;
+use tokio::sync::oneshot;
+use tracing::{error, warn};
+use vault_gate::VaultGate;
+
+use crate::crypto::integrity::hashing::Hashable;
+
+pub mod auth;
+pub mod session;
+pub mod vault_gate;
+
+#[derive(Debug, Clone)]
+pub struct Credentials {
+    pub id: i32,
+    pub pubkey: authn::PublicKey,
+}
+
+impl Hashable for authn::PublicKey {
+    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
+        hasher.update(self.to_bytes());
+    }
+}
+
+impl Hashable for Credentials {
+    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
+        self.id.hash(hasher);
+        self.pubkey.hash(hasher);
+    }
+}
+
+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: db::DatabasePool,
+    pub(crate) actors: GlobalActors,
+}
+
+impl UserAgentConnection {
+    pub fn new(db: 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(),
+        creds,
+        oob_sender,
+    )))
+}

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

@@ -1,115 +1,32 @@
-use std::sync::Mutex;
 
 use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
 use arbiter_crypto::{
     authn,
-    safecell::{SafeCell, SafeCellHandle as _},
+    safecell::SafeCellHandle as _,
 };
-use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
+use chacha20poly1305::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 tracing::error;
 
 use crate::actors::flow_coordinator::client_connect_approval::ClientApprovalAnswer;
-use crate::actors::keyholder::KeyHolderState;
-use crate::actors::user_agent::session::Error;
-use crate::actors::{
-    evm::{
+use crate::actors::evm::{
         ClientSignTransaction, Generate, ListWallets, SignTransactionError as EvmSignError,
         UseragentCreateGrant, UseragentListGrants,
-    },
-    keyholder::{self, Bootstrap, TryUnseal},
-    user_agent::session::{
-        UserAgentSession,
-        state::{UnsealContext, UserAgentEvents, UserAgentStates},
-    },
-};
+    };
 use crate::db::models::{
     EvmWalletAccess, NewEvmWalletAccess, ProgramClient, ProgramClientMetadata,
 };
 use crate::evm::policies::{Grant, SpecificGrant};
+use crate::{
+    actors::vault::VaultState,
+};
 
-impl UserAgentSession {
-    fn take_unseal_secret(&mut self) -> Result<(EphemeralSecret, PublicKey), Error> {
-        let UserAgentStates::WaitingForUnsealKey(unseal_context) = self.state.state() else {
-            error!("Received encrypted key in invalid state");
-            return Err(Error::internal("Invalid state for unseal encrypted key"));
-        };
+use super::{Error, UserAgentSession};
 
-        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 {
@@ -132,160 +49,13 @@ pub enum GrantMutationError {
 #[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);
+    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<VaultState, Error> {
+        use crate::actors::vault::GetState;
 
-        self.transition(UserAgentEvents::UnsealRequest(UnsealContext {
-            secret: Mutex::new(Some(secret)),
-            client_public_key: client_pubkey,
-        }))?;
-
-        Ok(UnsealStartResponse {
-            server_pubkey: public_key,
-        })
-    }
-
-    #[message]
-    pub async fn handle_unseal_encrypted_key(
-        &mut self,
-        nonce: Vec<u8>,
-        ciphertext: Vec<u8>,
-        associated_data: Vec<u8>,
-    ) -> Result<(), UnsealError> {
-        let (ephemeral_secret, client_public_key) = match self.take_unseal_secret() {
-            Ok(values) => values,
-            Err(Error::State) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(UnsealError::InvalidKey);
-            }
-            Err(_err) => {
-                return Err(Error::internal("Failed to take unseal secret").into());
-            }
-        };
-
-        let seal_key_buffer = match Self::decrypt_client_key_material(
-            ephemeral_secret,
-            client_public_key,
-            &nonce,
-            &ciphertext,
-            &associated_data,
-        ) {
-            Ok(buffer) => buffer,
-            Err(()) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(UnsealError::InvalidKey);
-            }
-        };
-
-        match self
-            .props
-            .actors
-            .key_holder
-            .ask(TryUnseal {
-                seal_key_raw: seal_key_buffer,
-            })
-            .await
-        {
-            Ok(_) => {
-                info!("Successfully unsealed key with client-provided key");
-                self.transition(UserAgentEvents::ReceivedValidKey)?;
-                Ok(())
-            }
-            Err(SendError::HandlerError(keyholder::Error::InvalidKey)) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(UnsealError::InvalidKey)
-            }
-            Err(SendError::HandlerError(err)) => {
-                error!(?err, "Keyholder failed to unseal key");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(UnsealError::InvalidKey)
-            }
-            Err(err) => {
-                error!(?err, "Failed to send unseal request to keyholder");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(Error::internal("Vault actor error").into())
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_bootstrap_encrypted_key(
-        &mut self,
-        nonce: Vec<u8>,
-        ciphertext: Vec<u8>,
-        associated_data: Vec<u8>,
-    ) -> Result<(), BootstrapError> {
-        let (ephemeral_secret, client_public_key) = match self.take_unseal_secret() {
-            Ok(values) => values,
-            Err(Error::State) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(BootstrapError::InvalidKey);
-            }
-            Err(err) => return Err(err.into()),
-        };
-
-        let seal_key_buffer = match Self::decrypt_client_key_material(
-            ephemeral_secret,
-            client_public_key,
-            &nonce,
-            &ciphertext,
-            &associated_data,
-        ) {
-            Ok(buffer) => buffer,
-            Err(()) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(BootstrapError::InvalidKey);
-            }
-        };
-
-        match self
-            .props
-            .actors
-            .key_holder
-            .ask(Bootstrap {
-                seal_key_raw: seal_key_buffer,
-            })
-            .await
-        {
-            Ok(_) => {
-                info!("Successfully bootstrapped vault with client-provided key");
-                self.transition(UserAgentEvents::ReceivedValidKey)?;
-                Ok(())
-            }
-            Err(SendError::HandlerError(keyholder::Error::AlreadyBootstrapped)) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::AlreadyBootstrapped)
-            }
-            Err(SendError::HandlerError(err)) => {
-                error!(?err, "Keyholder failed to bootstrap vault");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::InvalidKey)
-            }
-            Err(err) => {
-                error!(?err, "Failed to send bootstrap request to keyholder");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::General(Error::internal(
-                    "Vault actor error",
-                )))
-            }
-        }
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<KeyHolderState, Error> {
-        use crate::actors::keyholder::GetState;
-
-        let vault_state = match self.props.actors.key_holder.ask(GetState {}).await {
+        let vault_state = match self.props.actors.vault.ask(GetState {}).await {
             Ok(state) => state,
             Err(err) => {
-                error!(?err, actor = "useragent", "keyholder.query.failed");
+                error!(?err, actor = "useragent", "vault.query.failed");
                 return Err(Error::internal("Vault is in broken state"));
             }
         };
@@ -374,7 +144,7 @@ impl UserAgentSession {
         //         Err(GrantMutationError::Internal)
         //     }
         // }
-       let _ = grant_id;
+        let _ = grant_id;
         todo!()
     }
 

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

@@ -3,18 +3,19 @@ use arbiter_crypto::authn;
 use std::{borrow::Cow, collections::HashMap};
 
 use arbiter_proto::transport::Sender;
-use async_trait::async_trait;
 use kameo::{Actor, actor::ActorRef, messages};
 use thiserror::Error;
 use tracing::error;
 
-use crate::actors::{
-    client::ClientProfile,
-    flow_coordinator::{RegisterUserAgent, client_connect_approval::ClientApprovalController},
-    user_agent::{OutOfBand, UserAgentConnection},
+use crate::{
+    actors::{
+        flow_coordinator::client_connect_approval::ClientApprovalController,
+        useragent_registry::ConnectUseragent,
+    },
+    peers::{client::ClientProfile, user_agent::Credentials},
 };
-mod state;
-use state::{DummyContext, UserAgentEvents, UserAgentStateMachine};
+
+use super::{OutOfBand, UserAgentConnection};
 
 #[derive(Debug, Error)]
 pub enum Error {
@@ -52,48 +53,28 @@ pub struct PendingClientApproval {
 }
 
 pub struct UserAgentSession {
+    creds: Credentials,
     props: UserAgentConnection,
-    state: UserAgentStateMachine<DummyContext>,
     sender: Box<dyn Sender<OutOfBand>>,
 
     pending_client_approvals: HashMap<Vec<u8>, PendingClientApproval>,
 }
 
-pub mod connection;
+pub mod handlers;
 
 impl UserAgentSession {
-    pub(crate) fn new(props: UserAgentConnection, sender: Box<dyn Sender<OutOfBand>>) -> Self {
+    pub(crate) fn new(
+        props: UserAgentConnection,
+        creds: Credentials,
+        sender: Box<dyn Sender<OutOfBand>>,
+    ) -> Self {
         Self {
+            creds,
             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]
@@ -140,17 +121,17 @@ impl Actor for UserAgentSession {
     ) -> Result<Self, Self::Error> {
         args.props
             .actors
-            .flow_coordinator
-            .ask(RegisterUserAgent {
+            .useragent_registry
+            .ask(ConnectUseragent {
                 actor: this.clone(),
             })
             .await
             .map_err(|err| {
                 error!(
                     ?err,
-                    "Failed to register user agent connection with flow coordinator"
+                    "Failed to register user agent connection with user agent registry"
                 );
-                Error::internal("Failed to register user agent connection with flow coordinator")
+                Error::internal("Failed to register user agent connection with user agent registry")
             })?;
         Ok(args)
     }

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

@@ -0,0 +1,296 @@
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use arbiter_proto::transport::Bi;
+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, warn};
+use x25519_dalek::{EphemeralSecret, PublicKey, SharedSecret};
+
+pub mod state;
+use state::*;
+
+use super::Credentials;
+use crate::{
+    actors::{
+        GlobalActors,
+        vault::{self, Bootstrap, GetState, TryUnseal, VaultState, events},
+    },
+    crypto::integrity::{self},
+    db::DatabasePool,
+    peers::user_agent::UserAgentConnection,
+};
+
+#[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 async fn handle_handshake(
+        &mut self,
+        client_pubkey: x25519_dalek::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.clone(),
+            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 seal_key_buffer = match Self::decrypt_key(secret, &nonce, &ciphertext, &associated_data)
+        {
+            Ok(buffer) => buffer,
+            Err(()) => {
+                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").into())
+            }
+        }
+    }
+
+    #[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 seal_key_buffer = match Self::decrypt_key(secret, &nonce, &ciphertext, &associated_data)
+        {
+            Ok(buffer) => buffer,
+            Err(()) => {
+                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 +1,16 @@
+
+use x25519_dalek::{PublicKey, SharedSecret};
+
+pub struct Handshake {
+    client_pubkey: PublicKey,
+}
+
+#[derive(Default)]
+pub enum State {
+    #[default]
+    Idle,
+    ReadyForExchange {
+        server_key: PublicKey,
+        secret: SharedSecret,
+    },
+}

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

@@ -1,17 +1,14 @@
 use arbiter_crypto::{
-    authn::{self, CLIENT_CONTEXT, format_challenge},
+    authn::{self, AuthChallenge, CLIENT_CONTEXT},
     safecell::{SafeCell, SafeCellHandle as _},
 };
 use arbiter_proto::ClientMetadata;
 use arbiter_proto::transport::{Receiver, Sender};
 use arbiter_server::{
-    actors::{
-        GlobalActors,
-        client::{ClientConnection, ClientCredentials, auth, connect_client},
-        keyholder::Bootstrap,
-    },
+    actors::{GlobalActors, vault::Bootstrap},
     crypto::integrity,
     db::{self, schema},
+    peers::client::{ClientConnection, ClientCredentials, auth, connect_client},
 };
 use diesel::{ExpressionMethods as _, NullableExpressionMethods as _, QueryDsl as _, insert_into};
 use diesel_async::RunQueryDsl;
@@ -58,10 +55,9 @@ async fn insert_registered_client(
 
     integrity::sign_entity(
         &mut conn,
-        &actors.key_holder,
+        &actors.vault,
         &ClientCredentials {
             pubkey: pubkey.into(),
-            nonce: 1,
         },
         client_id,
     )
@@ -69,12 +65,8 @@ async fn insert_registered_client(
     .unwrap();
 }
 
-fn sign_client_challenge(
-    key: &SigningKey<MlDsa87>,
-    nonce: i32,
-    pubkey: &authn::PublicKey,
-) -> authn::Signature {
-    let challenge = format_challenge(nonce, &pubkey.to_bytes());
+fn sign_client_challenge(key: &SigningKey<MlDsa87>, challenge: &AuthChallenge) -> authn::Signature {
+    let challenge = challenge.format();
     key.signing_key()
         .sign_deterministic(&challenge, CLIENT_CONTEXT)
         .unwrap()
@@ -89,10 +81,7 @@ async fn insert_bootstrap_sentinel_useragent(db: &db::DatabasePool) {
         .to_vec();
 
     insert_into(schema::useragent_client::table)
-        .values((
-            schema::useragent_client::public_key.eq(sentinel_key),
-            schema::useragent_client::key_type.eq(1i32),
-        ))
+        .values((schema::useragent_client::public_key.eq(sentinel_key),))
         .execute(&mut conn)
         .await
         .unwrap();
@@ -103,7 +92,7 @@ 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()),
         })
@@ -178,14 +167,14 @@ 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),
+            auth::Outbound::AuthChallenge { challenge } => challenge,
             other => panic!("Expected AuthChallenge, got {other:?}"),
         },
         Err(err) => panic!("Expected Ok response, got Err({err:?})"),
     };
 
     // Sign the challenge and send solution
-    let signature = sign_client_challenge(&new_key, challenge.1, &challenge.0);
+    let signature = sign_client_challenge(&new_key, &challenge);
 
     test_transport
         .send(auth::Inbound::AuthChallengeSolution { signature })
@@ -233,11 +222,11 @@ pub async fn test_metadata_unchanged_does_not_append_history() {
         .unwrap();
 
     let response = test_transport.recv().await.unwrap().unwrap();
-    let (pubkey, nonce) = match response {
-        auth::Outbound::AuthChallenge { pubkey, nonce } => (pubkey, nonce),
+    let challenge = match response {
+        auth::Outbound::AuthChallenge { challenge } => challenge,
         other => panic!("Expected AuthChallenge, got {other:?}"),
     };
-    let signature = sign_client_challenge(&new_key, nonce, &pubkey);
+    let signature = sign_client_challenge(&new_key, &challenge);
     test_transport
         .send(auth::Inbound::AuthChallengeSolution { signature })
         .await
@@ -295,11 +284,11 @@ pub async fn test_metadata_change_appends_history_and_repoints_binding() {
         .unwrap();
 
     let response = test_transport.recv().await.unwrap().unwrap();
-    let (pubkey, nonce) = match response {
-        auth::Outbound::AuthChallenge { pubkey, nonce } => (pubkey, nonce),
+    let challenge = match response {
+        auth::Outbound::AuthChallenge { challenge } => challenge,
         other => panic!("Expected AuthChallenge, got {other:?}"),
     };
-    let signature = sign_client_challenge(&new_key, nonce, &pubkey);
+    let signature = sign_client_challenge(&new_key, &challenge);
     test_transport
         .send(auth::Inbound::AuthChallengeSolution { signature })
         .await

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

@@ -1,7 +1,7 @@
 use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_proto::transport::{Bi, Error, Receiver, Sender};
 use arbiter_server::{
-    actors::keyholder::KeyHolder,
+    actors::{GlobalActors, vault::Vault},
     db::{self, schema},
 };
 
@@ -11,8 +11,10 @@ use diesel_async::RunQueryDsl;
 use tokio::sync::mpsc;
 
 #[allow(dead_code)]
-pub async fn bootstrapped_keyholder(db: &db::DatabasePool) -> KeyHolder {
-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+pub async fn bootstrapped_vault(db: &db::DatabasePool) -> Vault {
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
     actor
         .bootstrap(SafeCell::new(b"test-seal-key".to_vec()))
         .await

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

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

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

@@ -1,44 +1,152 @@
 use arbiter_crypto::{
-    authn::{self, USERAGENT_CONTEXT, format_challenge},
+    authn::{self, AuthChallenge, USERAGENT_CONTEXT},
     safecell::{SafeCell, SafeCellHandle as _},
 };
 
-use arbiter_proto::transport::{Receiver, Sender};
+use arbiter_proto::transport::{Error as TransportError, Receiver, Sender};
 use arbiter_server::{
-    actors::{
-        GlobalActors,
-        bootstrap::GetToken,
-        keyholder::Bootstrap,
-        user_agent::{UserAgentConnection, UserAgentCredentials, auth},
-    },
+    actors::{GlobalActors, bootstrap::GetToken, vault::Bootstrap},
     crypto::integrity,
     db::{self, schema},
+    peers::user_agent::{self, Credentials, UserAgentConnection, auth, vault_gate},
 };
+use async_trait::async_trait;
 use diesel::{ExpressionMethods as _, QueryDsl, insert_into};
 use diesel_async::RunQueryDsl;
 use ml_dsa::{KeyGen, MlDsa87, SigningKey, signature::Keypair as _};
+use tokio::sync::mpsc;
 
 use super::common::ChannelTransport;
 
 fn sign_useragent_challenge(
     key: &SigningKey<MlDsa87>,
-    nonce: i32,
-    pubkey_bytes: &[u8],
+    challenge: &AuthChallenge,
 ) -> authn::Signature {
-    let challenge = format_challenge(nonce, pubkey_bytes);
+    let challenge = challenge.format();
     key.signing_key()
         .sign_deterministic(&challenge, USERAGENT_CONTEXT)
         .unwrap()
         .into()
 }
 
+fn tamper_challenge(challenge: &AuthChallenge) -> AuthChallenge {
+    let mut challenge = challenge.clone();
+    challenge.nonce[0] ^= 1;
+    challenge
+}
+
+struct NullOobSender;
+
+#[async_trait]
+impl Sender<user_agent::OutOfBand> for NullOobSender {
+    async fn send(&mut self, _item: user_agent::OutOfBand) -> Result<(), TransportError> {
+        Ok(())
+    }
+}
+
+struct StartServerTransport {
+    auth_rx: mpsc::Receiver<auth::Inbound>,
+    auth_tx: mpsc::Sender<Result<auth::Outbound, auth::Error>>,
+    vault_rx: mpsc::Receiver<vault_gate::Inbound>,
+    vault_tx: mpsc::Sender<Result<vault_gate::Outbound, vault_gate::Error>>,
+}
+
+struct StartTestTransport {
+    auth_rx: mpsc::Receiver<Result<auth::Outbound, auth::Error>>,
+    auth_tx: mpsc::Sender<auth::Inbound>,
+}
+
+fn start_transport_pair() -> (StartServerTransport, StartTestTransport) {
+    let (auth_in_tx, auth_in_rx) = mpsc::channel(10);
+    let (auth_out_tx, auth_out_rx) = mpsc::channel(10);
+    let (_vault_in_tx, vault_in_rx) = mpsc::channel(10);
+    let (vault_out_tx, _vault_out_rx) = mpsc::channel(10);
+
+    (
+        StartServerTransport {
+            auth_rx: auth_in_rx,
+            auth_tx: auth_out_tx,
+            vault_rx: vault_in_rx,
+            vault_tx: vault_out_tx,
+        },
+        StartTestTransport {
+            auth_rx: auth_out_rx,
+            auth_tx: auth_in_tx,
+        },
+    )
+}
+
+#[async_trait]
+impl Receiver<auth::Inbound> for StartServerTransport {
+    async fn recv(&mut self) -> Option<auth::Inbound> {
+        self.auth_rx.recv().await
+    }
+}
+
+#[async_trait]
+impl Sender<Result<auth::Outbound, auth::Error>> for StartServerTransport {
+    async fn send(&mut self, item: Result<auth::Outbound, auth::Error>) -> Result<(), TransportError> {
+        self.auth_tx
+            .send(item)
+            .await
+            .map_err(|_| TransportError::ChannelClosed)
+    }
+}
+
+impl arbiter_proto::transport::Bi<auth::Inbound, Result<auth::Outbound, auth::Error>>
+    for StartServerTransport
+{
+}
+
+#[async_trait]
+impl Receiver<vault_gate::Inbound> for StartServerTransport {
+    async fn recv(&mut self) -> Option<vault_gate::Inbound> {
+        self.vault_rx.recv().await
+    }
+}
+
+#[async_trait]
+impl Sender<Result<vault_gate::Outbound, vault_gate::Error>> for StartServerTransport {
+    async fn send(
+        &mut self,
+        item: Result<vault_gate::Outbound, vault_gate::Error>,
+    ) -> Result<(), TransportError> {
+        self.vault_tx
+            .send(item)
+            .await
+            .map_err(|_| TransportError::ChannelClosed)
+    }
+}
+
+impl arbiter_proto::transport::Bi<vault_gate::Inbound, Result<vault_gate::Outbound, vault_gate::Error>>
+    for StartServerTransport
+{
+}
+
+#[async_trait]
+impl Receiver<Result<auth::Outbound, auth::Error>> for StartTestTransport {
+    async fn recv(&mut self) -> Option<Result<auth::Outbound, auth::Error>> {
+        self.auth_rx.recv().await
+    }
+}
+
+#[async_trait]
+impl Sender<auth::Inbound> for StartTestTransport {
+    async fn send(&mut self, item: auth::Inbound) -> Result<(), TransportError> {
+        self.auth_tx
+            .send(item)
+            .await
+            .map_err(|_| TransportError::ChannelClosed)
+    }
+}
+
 #[tokio::test]
 #[test_log::test]
 pub async fn test_bootstrap_token_auth() {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
     actors
-        .key_holder
+        .vault
         .ask(Bootstrap {
             seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
         })
@@ -46,11 +154,11 @@ pub async fn test_bootstrap_token_auth() {
         .unwrap();
     let token = actors.bootstrapper.ask(GetToken).await.unwrap().unwrap();
 
-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
     let db_for_task = db.clone();
     let task = tokio::spawn(async move {
         let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        auth::authenticate(&mut props, &mut server_transport).await
     });
 
     let new_key = MlDsa87::key_gen(&mut rand::rng());
@@ -62,14 +170,29 @@ pub async fn test_bootstrap_token_auth() {
         .await
         .unwrap();
 
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive challenge");
+    let challenge = match response {
+        Ok(auth::Outbound::AuthChallenge { challenge }) => challenge,
+        other => panic!("Expected AuthChallenge, got {other:?}"),
+    };
+
+    let signature = sign_useragent_challenge(&new_key, &challenge);
+
+    test_transport
+        .send(auth::Inbound::AuthChallengeSolution {
+            signature: signature.to_bytes(),
+        })
+        .await
+        .unwrap();
+
     let response = test_transport
         .recv()
         .await
         .expect("should receive auth result");
-    match response {
-        Ok(auth::Outbound::AuthSuccess) => {}
-        other => panic!("Expected AuthSuccess, got {other:?}"),
-    }
+    assert!(matches!(response, Ok(auth::Outbound::AuthSuccess)));
 
     task.await.unwrap().unwrap();
 
@@ -88,11 +211,11 @@ pub async fn test_bootstrap_invalid_token_auth() {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
 
-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
     let db_for_task = db.clone();
     let task = tokio::spawn(async move {
         let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        auth::authenticate(&mut props, &mut server_transport).await
     });
 
     let new_key = MlDsa87::key_gen(&mut rand::rng());
@@ -104,6 +227,23 @@ pub async fn test_bootstrap_invalid_token_auth() {
         .await
         .unwrap();
 
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive challenge");
+    let challenge = match response {
+        Ok(auth::Outbound::AuthChallenge { challenge }) => challenge,
+        other => panic!("Expected AuthChallenge, got {other:?}"),
+    };
+
+    let signature = sign_useragent_challenge(&new_key, &challenge);
+    test_transport
+        .send(auth::Inbound::AuthChallengeSolution {
+            signature: signature.to_bytes(),
+        })
+        .await
+        .unwrap();
+
     assert!(matches!(
         task.await.unwrap(),
         Err(auth::Error::InvalidBootstrapToken)
@@ -124,7 +264,7 @@ pub async fn test_challenge_auth() {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
     actors
-        .key_holder
+        .vault
         .ask(Bootstrap {
             seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
         })
@@ -137,20 +277,17 @@ pub async fn test_challenge_auth() {
     {
         let mut conn = db.get().await.unwrap();
         let id: i32 = insert_into(schema::useragent_client::table)
-            .values((
-                schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
-                schema::useragent_client::key_type.eq(1i32),
-            ))
+            .values((schema::useragent_client::public_key.eq(pubkey_bytes.clone()),))
             .returning(schema::useragent_client::id)
             .get_result(&mut conn)
             .await
             .unwrap();
         integrity::sign_entity(
             &mut conn,
-            &actors.key_holder,
-            &UserAgentCredentials {
+            &actors.vault,
+            &Credentials {
+                id,
                 pubkey: new_key.verifying_key().into(),
-                nonce: 1,
             },
             id,
         )
@@ -158,11 +295,11 @@ pub async fn test_challenge_auth() {
         .unwrap();
     }
 
-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
     let db_for_task = db.clone();
     let task = tokio::spawn(async move {
         let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        auth::authenticate(&mut props, &mut server_transport).await
     });
 
     test_transport
@@ -179,13 +316,13 @@ pub async fn test_challenge_auth() {
         .expect("should receive challenge");
     let challenge = match response {
         Ok(resp) => match resp {
-            auth::Outbound::AuthChallenge { nonce } => nonce,
+            auth::Outbound::AuthChallenge { challenge } => challenge,
             other => panic!("Expected AuthChallenge, got {other:?}"),
         },
         Err(err) => panic!("Expected Ok response, got Err({err:?})"),
     };
 
-    let signature = sign_useragent_challenge(&new_key, challenge, &pubkey_bytes);
+    let signature = sign_useragent_challenge(&new_key, &challenge);
 
     test_transport
         .send(auth::Inbound::AuthChallengeSolution {
@@ -213,7 +350,7 @@ pub async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed()
     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()),
         })
@@ -226,81 +363,17 @@ pub async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed()
     {
         let mut conn = db.get().await.unwrap();
         insert_into(schema::useragent_client::table)
-            .values((
-                schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
-                schema::useragent_client::key_type.eq(1i32),
-            ))
+            .values((schema::useragent_client::public_key.eq(pubkey_bytes.clone()),))
             .execute(&mut conn)
             .await
             .unwrap();
     }
 
-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (server_transport, mut test_transport) = start_transport_pair();
     let db_for_task = db.clone();
     let task = tokio::spawn(async move {
         let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
-    });
-
-    test_transport
-        .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key().into(),
-            bootstrap_token: None,
-        })
-        .await
-        .unwrap();
-
-    assert!(matches!(
-        task.await.unwrap(),
-        Err(auth::Error::Internal { .. })
-    ));
-}
-
-#[tokio::test]
-#[test_log::test]
-pub async fn test_challenge_auth_rejects_invalid_signature() {
-    let db = db::create_test_pool().await;
-    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
-    actors
-        .key_holder
-        .ask(Bootstrap {
-            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
-        })
-        .await
-        .unwrap();
-
-    let new_key = MlDsa87::key_gen(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().encode().to_vec();
-
-    {
-        let mut conn = db.get().await.unwrap();
-        let id: i32 = insert_into(schema::useragent_client::table)
-            .values((
-                schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
-                schema::useragent_client::key_type.eq(1i32),
-            ))
-            .returning(schema::useragent_client::id)
-            .get_result(&mut conn)
-            .await
-            .unwrap();
-        integrity::sign_entity(
-            &mut conn,
-            &actors.key_holder,
-            &UserAgentCredentials {
-                pubkey: new_key.verifying_key().into(),
-                nonce: 1,
-            },
-            id,
-        )
-        .await
-        .unwrap();
-    }
-
-    let (server_transport, mut test_transport) = ChannelTransport::new();
-    let db_for_task = db.clone();
-    let task = tokio::spawn(async move {
-        let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        user_agent::start(&mut props, server_transport, Box::new(NullOobSender)).await
     });
 
     test_transport
@@ -317,13 +390,98 @@ pub async fn test_challenge_auth_rejects_invalid_signature() {
         .expect("should receive challenge");
     let challenge = match response {
         Ok(resp) => match resp {
-            auth::Outbound::AuthChallenge { nonce } => nonce,
+            auth::Outbound::AuthChallenge { challenge } => challenge,
             other => panic!("Expected AuthChallenge, got {other:?}"),
         },
         Err(err) => panic!("Expected Ok response, got Err({err:?})"),
     };
 
-    let signature = sign_useragent_challenge(&new_key, challenge + 1, &pubkey_bytes);
+    let signature = sign_useragent_challenge(&new_key, &challenge);
+
+    test_transport
+        .send(auth::Inbound::AuthChallengeSolution {
+            signature: signature.to_bytes(),
+        })
+        .await
+        .unwrap();
+
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive auth result");
+    assert!(matches!(response, Ok(auth::Outbound::AuthSuccess)));
+
+    assert!(matches!(
+        task.await.unwrap(),
+        Err(user_agent::Error::Internal(_))
+    ));
+}
+
+#[tokio::test]
+#[test_log::test]
+pub async fn test_challenge_auth_rejects_invalid_signature() {
+    let db = db::create_test_pool().await;
+    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+    actors
+        .vault
+        .ask(Bootstrap {
+            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
+        })
+        .await
+        .unwrap();
+
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
+    let pubkey_bytes = new_key.verifying_key().encode().to_vec();
+
+    {
+        let mut conn = db.get().await.unwrap();
+        let id: i32 = insert_into(schema::useragent_client::table)
+            .values((schema::useragent_client::public_key.eq(pubkey_bytes.clone()),))
+            .returning(schema::useragent_client::id)
+            .get_result(&mut conn)
+            .await
+            .unwrap();
+        integrity::sign_entity(
+            &mut conn,
+            &actors.vault,
+            &Credentials {
+                id,
+                pubkey: new_key.verifying_key().into(),
+            },
+            id,
+        )
+        .await
+        .unwrap();
+    }
+
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
+    let db_for_task = db.clone();
+    let task = tokio::spawn(async move {
+        let mut props = UserAgentConnection::new(db_for_task, actors);
+        auth::authenticate(&mut props, &mut server_transport).await
+    });
+
+    test_transport
+        .send(auth::Inbound::AuthChallengeRequest {
+            pubkey: new_key.verifying_key().into(),
+            bootstrap_token: None,
+        })
+        .await
+        .unwrap();
+
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive challenge");
+    let challenge = match response {
+        Ok(resp) => match resp {
+            auth::Outbound::AuthChallenge { challenge } => challenge,
+            other => panic!("Expected AuthChallenge, got {other:?}"),
+        },
+        Err(err) => panic!("Expected Ok response, got Err({err:?})"),
+    };
+
+    let signature = sign_useragent_challenge(&new_key, &tamper_challenge(&challenge));
 
     test_transport
         .send(auth::Inbound::AuthChallengeSolution {

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

@@ -1,49 +1,62 @@
-use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use arbiter_crypto::{
+    authn,
+    safecell::{SafeCell, SafeCellHandle as _},
+};
 use arbiter_server::{
     actors::{
         GlobalActors,
-        keyholder::{Bootstrap, Seal},
-        user_agent::{
-            UserAgentSession,
-            session::connection::{HandleUnsealEncryptedKey, HandleUnsealRequest, UnsealError},
-        },
+        vault::{Bootstrap, Seal},
     },
     db,
+    peers::user_agent::{
+        Credentials,
+        vault_gate::{
+            Error as VaultGateError, HandleHandshake, HandleUnsealEncryptedKey, VaultGate,
+        },
+    },
 };
 
 use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
 use kameo::actor::Spawn as _;
+use tokio::sync::oneshot;
 use x25519_dalek::{EphemeralSecret, PublicKey};
 
-async fn setup_sealed_user_agent(
+async fn setup_sealed_gate(
     seal_key: &[u8],
-) -> (db::DatabasePool, kameo::actor::ActorRef<UserAgentSession>) {
+) -> (
+    db::DatabasePool,
+    kameo::actor::ActorRef<VaultGate>,
+    oneshot::Receiver<Result<(), VaultGateError>>,
+) {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
 
     actors
-        .key_holder
+        .vault
         .ask(Bootstrap {
             seal_key_raw: SafeCell::new(seal_key.to_vec()),
         })
         .await
         .unwrap();
-    actors.key_holder.ask(Seal).await.unwrap();
+    actors.vault.ask(Seal).await.unwrap();
 
-    let session = UserAgentSession::spawn(UserAgentSession::new_test(db.clone(), actors));
+    let (promotion_tx, promotion_rx) = oneshot::channel();
+    let pubkey = authn::SigningKey::generate().public_key();
+    let auth_creds = Credentials { id: 1, pubkey };
+    let gate = VaultGate::spawn(VaultGate::new(auth_creds, actors, db.clone(), promotion_tx));
 
-    (db, session)
+    (db, gate, promotion_rx)
 }
 
 async fn client_dh_encrypt(
-    user_agent: &kameo::actor::ActorRef<UserAgentSession>,
+    gate: &kameo::actor::ActorRef<VaultGate>,
     key_to_send: &[u8],
 ) -> HandleUnsealEncryptedKey {
     let client_secret = EphemeralSecret::random();
     let client_public = PublicKey::from(&client_secret);
 
-    let response = user_agent
-        .ask(HandleUnsealRequest {
+    let response = gate
+        .ask(HandleHandshake {
             client_pubkey: client_public,
         })
         .await
@@ -71,26 +84,26 @@ async fn client_dh_encrypt(
 #[test_log::test]
 pub async fn test_unseal_success() {
     let seal_key = b"test-seal-key";
-    let (_db, user_agent) = setup_sealed_user_agent(seal_key).await;
+    let (_db, gate, _promotion_rx) = setup_sealed_gate(seal_key).await;
 
-    let encrypted_key = client_dh_encrypt(&user_agent, seal_key).await;
+    let encrypted_key = client_dh_encrypt(&gate, seal_key).await;
 
-    let response = user_agent.ask(encrypted_key).await;
+    let response = gate.ask(encrypted_key).await;
     assert!(matches!(response, Ok(())));
 }
 
 #[tokio::test]
 #[test_log::test]
 pub async fn test_unseal_wrong_seal_key() {
-    let (_db, user_agent) = setup_sealed_user_agent(b"correct-key").await;
+    let (_db, gate, _promotion_rx) = setup_sealed_gate(b"correct-key").await;
 
-    let encrypted_key = client_dh_encrypt(&user_agent, b"wrong-key").await;
+    let encrypted_key = client_dh_encrypt(&gate, b"wrong-key").await;
 
-    let response = user_agent.ask(encrypted_key).await;
+    let response = gate.ask(encrypted_key).await;
     assert!(matches!(
         response,
         Err(kameo::error::SendError::HandlerError(
-            UnsealError::InvalidKey
+            VaultGateError::InvalidKey
         ))
     ));
 }
@@ -98,19 +111,18 @@ pub async fn test_unseal_wrong_seal_key() {
 #[tokio::test]
 #[test_log::test]
 pub async fn test_unseal_corrupted_ciphertext() {
-    let (_db, user_agent) = setup_sealed_user_agent(b"test-key").await;
+    let (_db, gate, _promotion_rx) = setup_sealed_gate(b"test-key").await;
 
     let client_secret = EphemeralSecret::random();
     let client_public = PublicKey::from(&client_secret);
 
-    user_agent
-        .ask(HandleUnsealRequest {
-            client_pubkey: client_public,
-        })
-        .await
-        .unwrap();
+    gate.ask(HandleHandshake {
+        client_pubkey: client_public,
+    })
+    .await
+    .unwrap();
 
-    let response = user_agent
+    let response = gate
         .ask(HandleUnsealEncryptedKey {
             nonce: vec![0u8; 24],
             ciphertext: vec![0u8; 32],
@@ -121,7 +133,7 @@ pub async fn test_unseal_corrupted_ciphertext() {
     assert!(matches!(
         response,
         Err(kameo::error::SendError::HandlerError(
-            UnsealError::InvalidKey
+            VaultGateError::InvalidKey
         ))
     ));
 }
@@ -130,24 +142,24 @@ pub async fn test_unseal_corrupted_ciphertext() {
 #[test_log::test]
 pub async fn test_unseal_retry_after_invalid_key() {
     let seal_key = b"real-seal-key";
-    let (_db, user_agent) = setup_sealed_user_agent(seal_key).await;
+    let (_db, gate, _promotion_rx) = setup_sealed_gate(seal_key).await;
 
     {
-        let encrypted_key = client_dh_encrypt(&user_agent, b"wrong-key").await;
+        let encrypted_key = client_dh_encrypt(&gate, b"wrong-key").await;
 
-        let response = user_agent.ask(encrypted_key).await;
+        let response = gate.ask(encrypted_key).await;
         assert!(matches!(
             response,
             Err(kameo::error::SendError::HandlerError(
-                UnsealError::InvalidKey
+                VaultGateError::InvalidKey
             ))
         ));
     }
 
     {
-        let encrypted_key = client_dh_encrypt(&user_agent, seal_key).await;
+        let encrypted_key = client_dh_encrypt(&gate, seal_key).await;
 
-        let response = user_agent.ask(encrypted_key).await;
+        let response = gate.ask(encrypted_key).await;
         assert!(matches!(response, Ok(())));
     }
 }

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

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

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

@@ -2,7 +2,10 @@ use std::collections::{HashMap, HashSet};
 
 use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_server::{
-    actors::keyholder::{CreateNew, Error, KeyHolder},
+    actors::{
+        GlobalActors,
+        vault::{CreateNew, Error, Vault},
+    },
     db::{self, models, schema},
 };
 
@@ -14,7 +17,7 @@ use tokio::task::JoinSet;
 use crate::common;
 
 async fn write_concurrently(
-    actor: ActorRef<KeyHolder>,
+    actor: ActorRef<Vault>,
     prefix: &'static str,
     count: usize,
 ) -> Vec<(i32, Vec<u8>)> {
@@ -44,7 +47,7 @@ async fn write_concurrently(
 #[test_log::test]
 async fn concurrent_create_new_no_duplicate_nonces_() {
     let db = db::create_test_pool().await;
-    let actor = KeyHolder::spawn(common::bootstrapped_keyholder(&db).await);
+    let actor = Vault::spawn(common::bootstrapped_vault(&db).await);
 
     let writes = write_concurrently(actor, "nonce-unique", 32).await;
     assert_eq!(writes.len(), 32);
@@ -66,7 +69,7 @@ async fn concurrent_create_new_no_duplicate_nonces_() {
 #[test_log::test]
 async fn concurrent_create_new_root_nonce_never_moves_backward() {
     let db = db::create_test_pool().await;
-    let actor = KeyHolder::spawn(common::bootstrapped_keyholder(&db).await);
+    let actor = Vault::spawn(common::bootstrapped_vault(&db).await);
 
     write_concurrently(actor, "root-max", 24).await;
 
@@ -94,7 +97,7 @@ async fn concurrent_create_new_root_nonce_never_moves_backward() {
 #[test_log::test]
 async fn insert_failure_does_not_create_partial_row() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
     let root_key_history_id = common::root_key_history_id(&db).await;
 
     let mut conn = db.get().await.unwrap();
@@ -156,12 +159,14 @@ async fn insert_failure_does_not_create_partial_row() {
 #[test_log::test]
 async fn decrypt_roundtrip_after_high_concurrency() {
     let db = db::create_test_pool().await;
-    let actor = KeyHolder::spawn(common::bootstrapped_keyholder(&db).await);
+    let actor = Vault::spawn(common::bootstrapped_vault(&db).await);
 
     let writes = write_concurrently(actor, "roundtrip", 40).await;
     let expected: HashMap<i32, Vec<u8>> = writes.into_iter().collect();
 
-    let mut decryptor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut decryptor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
     decryptor
         .try_unseal(SafeCell::new(b"test-seal-key".to_vec()))
         .await

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

@@ -1,6 +1,9 @@
 use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_server::{
-    actors::keyholder::{Error, KeyHolder},
+    actors::{
+        GlobalActors,
+        vault::{Error, Vault},
+    },
     crypto::encryption::v1::{Nonce, ROOT_KEY_TAG},
     db::{self, models, schema},
 };
@@ -14,7 +17,9 @@ use crate::common;
 #[test_log::test]
 async fn test_bootstrap() {
     let db = db::create_test_pool().await;
-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
 
     let seal_key = SafeCell::new(b"test-seal-key".to_vec());
     actor.bootstrap(seal_key).await.unwrap();
@@ -37,7 +42,7 @@ async fn test_bootstrap() {
 #[test_log::test]
 async fn test_bootstrap_rejects_double() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let seal_key2 = SafeCell::new(b"test-seal-key".to_vec());
     let err = actor.bootstrap(seal_key2).await.unwrap_err();
@@ -48,7 +53,9 @@ async fn test_bootstrap_rejects_double() {
 #[test_log::test]
 async fn test_create_new_before_bootstrap_fails() {
     let db = db::create_test_pool().await;
-    let mut actor = KeyHolder::new(db).await.unwrap();
+    let mut actor = Vault::new(db, GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
 
     let err = actor
         .create_new(SafeCell::new(b"data".to_vec()))
@@ -61,7 +68,9 @@ async fn test_create_new_before_bootstrap_fails() {
 #[test_log::test]
 async fn test_decrypt_before_bootstrap_fails() {
     let db = db::create_test_pool().await;
-    let mut actor = KeyHolder::new(db).await.unwrap();
+    let mut actor = Vault::new(db, GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
 
     let err = actor.decrypt(1).await.unwrap_err();
     assert!(matches!(err, Error::NotBootstrapped));
@@ -71,19 +80,21 @@ async fn test_decrypt_before_bootstrap_fails() {
 #[test_log::test]
 async fn test_new_restores_sealed_state() {
     let db = db::create_test_pool().await;
-    let actor = common::bootstrapped_keyholder(&db).await;
+    let actor = common::bootstrapped_vault(&db).await;
     drop(actor);
 
-    let mut actor2 = KeyHolder::new(db).await.unwrap();
+    let mut actor2 = Vault::new(db, GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
     let err = actor2.decrypt(1).await.unwrap_err();
-    assert!(matches!(err, Error::NotBootstrapped));
+    assert!(matches!(err, Error::Sealed));
 }
 
 #[tokio::test]
 #[test_log::test]
 async fn test_unseal_correct_password() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let plaintext = b"survive a restart";
     let aead_id = actor
@@ -92,7 +103,9 @@ async fn test_unseal_correct_password() {
         .unwrap();
     drop(actor);
 
-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
     let seal_key = SafeCell::new(b"test-seal-key".to_vec());
     actor.try_unseal(seal_key).await.unwrap();
 
@@ -104,7 +117,7 @@ async fn test_unseal_correct_password() {
 #[test_log::test]
 async fn test_unseal_wrong_then_correct_password() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let plaintext = b"important data";
     let aead_id = actor
@@ -113,7 +126,9 @@ async fn test_unseal_wrong_then_correct_password() {
         .unwrap();
     drop(actor);
 
-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
 
     let bad_key = SafeCell::new(b"wrong-password".to_vec());
     let err = actor.try_unseal(bad_key).await.unwrap_err();

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

@@ -2,7 +2,7 @@ use std::collections::HashSet;
 
 use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_server::{
-    actors::keyholder::Error,
+    actors::vault::Error,
     crypto::encryption::v1::Nonce,
     db::{self, models, schema},
 };
@@ -16,7 +16,7 @@ use crate::common;
 #[test_log::test]
 async fn test_create_decrypt_roundtrip() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let plaintext = b"hello arbiter";
     let aead_id = actor
@@ -32,7 +32,7 @@ async fn test_create_decrypt_roundtrip() {
 #[test_log::test]
 async fn test_decrypt_nonexistent_returns_not_found() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let err = actor.decrypt(9999).await.unwrap_err();
     assert!(matches!(err, Error::NotFound));
@@ -42,7 +42,7 @@ async fn test_decrypt_nonexistent_returns_not_found() {
 #[test_log::test]
 async fn test_ciphertext_differs_across_entries() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let plaintext = b"same content";
     let id1 = actor
@@ -80,7 +80,7 @@ async fn test_ciphertext_differs_across_entries() {
 #[test_log::test]
 async fn test_nonce_never_reused() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let n = 5;
     for i in 0..n {
@@ -124,7 +124,7 @@ async fn test_nonce_never_reused() {
 #[test_log::test]
 async fn broken_db_nonce_format_fails_closed() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
     let root_key_history_id = common::root_key_history_id(&db).await;
 
     let mut conn = db.get().await.unwrap();
@@ -145,7 +145,7 @@ async fn broken_db_nonce_format_fails_closed() {
     assert!(matches!(err, Error::BrokenDatabase));
 
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
     let id = actor
         .create_new(SafeCell::new(b"decrypt target".to_vec()))
         .await

useragent/flutter_rust_bridge.yaml

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

useragent/lib/features/callouts/callout_event.dart

@@ -18,7 +18,6 @@ sealed class CalloutEvent with _$CalloutEvent {
     required CalloutData data,
   }) = CalloutEventAdded;
 
-  const factory CalloutEvent.cancelled({
-    required String id,
-  }) = CalloutEventCancelled;
+  const factory CalloutEvent.cancelled({required String id}) =
+      CalloutEventCancelled;
 }

useragent/lib/features/callouts/show_callout.dart

@@ -14,11 +14,8 @@ Future<void> showCallout(BuildContext context, WidgetRef ref, String id) async {
     barrierLabel: MaterialLocalizations.of(context).modalBarrierDismissLabel,
     barrierColor: Colors.transparent,
     transitionDuration: const Duration(milliseconds: 320),
-    pageBuilder: (_, animation, _) => _CalloutOverlay(
-      id: id,
-      data: data,
-      animation: animation,
-    ),
+    pageBuilder: (_, animation, _) =>
+        _CalloutOverlay(id: id, data: data, animation: animation),
   );
 }
 
@@ -35,22 +32,25 @@ class _CalloutOverlay extends ConsumerWidget {
 
   @override
   Widget build(BuildContext context, WidgetRef ref) {
-    ref.listen(
-      calloutManagerProvider.select((map) => map.containsKey(id)),
-      (wasPresent, isPresent) {
-        if (wasPresent == true && !isPresent && context.mounted) {
-          Navigator.of(context).pop();
-        }
-      },
-    );
+    ref.listen(calloutManagerProvider.select((map) => map.containsKey(id)), (
+      wasPresent,
+      isPresent,
+    ) {
+      if (wasPresent == true && !isPresent && context.mounted) {
+        Navigator.of(context).pop();
+      }
+    });
 
     final content = switch (data) {
-      ConnectApprovalData(:final pubkey, :final clientInfo) => SdkConnectCallout(
-        pubkey: pubkey,
-        clientInfo: clientInfo,
-        onAccept: () => ref.read(calloutManagerProvider.notifier).sendDecision(id, true),
-        onDecline: () => ref.read(calloutManagerProvider.notifier).sendDecision(id, false),
-      ),
+      ConnectApprovalData(:final pubkey, :final clientInfo) =>
+        SdkConnectCallout(
+          pubkey: pubkey,
+          clientInfo: clientInfo,
+          onAccept: () =>
+              ref.read(calloutManagerProvider.notifier).sendDecision(id, true),
+          onDecline: () =>
+              ref.read(calloutManagerProvider.notifier).sendDecision(id, false),
+        ),
     };
 
     final barrierAnim = CurvedAnimation(

useragent/lib/features/callouts/show_callout_list.dart

@@ -14,7 +14,8 @@ Future<void> showCalloutList(BuildContext context, WidgetRef ref) async {
     barrierLabel: MaterialLocalizations.of(context).modalBarrierDismissLabel,
     barrierColor: Colors.transparent,
     transitionDuration: const Duration(milliseconds: 280),
-    pageBuilder: (_, animation, __) => _CalloutListOverlay(animation: animation),
+    pageBuilder: (_, animation, __) =>
+        _CalloutListOverlay(animation: animation),
   );
 
   if (selectedId != null && context.mounted) {
@@ -51,7 +52,9 @@ class _CalloutListOverlay extends ConsumerWidget {
               child: AnimatedBuilder(
                 animation: barrierAnim,
                 builder: (_, __) => ColoredBox(
-                  color: Colors.black.withValues(alpha: 0.35 * barrierAnim.value),
+                  color: Colors.black.withValues(
+                    alpha: 0.35 * barrierAnim.value,
+                  ),
                 ),
               ),
             ),

useragent/lib/features/connection/arbiter_url.dart

@@ -50,7 +50,9 @@ class ArbiterUrl {
     try {
       return base64Url.decode(base64Url.normalize(cert));
     } on FormatException catch (error) {
-      throw FormatException("Invalid base64 in 'cert' query parameter: ${error.message}");
+      throw FormatException(
+        "Invalid base64 in 'cert' query parameter: ${error.message}",
+      );
     }
   }
 }

useragent/lib/features/connection/auth.dart

@@ -7,6 +7,7 @@ import 'package:arbiter/features/identity/pk_manager.dart';
 import 'package:arbiter/proto/arbiter.pbgrpc.dart';
 import 'package:arbiter/proto/user_agent/auth.pb.dart' as ua_auth;
 import 'package:arbiter/proto/user_agent.pb.dart';
+import 'package:arbiter/src/rust/api.dart';
 import 'package:grpc/grpc.dart';
 import 'package:mtcore/markettakers.dart';
 
@@ -61,11 +62,6 @@ Future<Connection> connectAndAuthorize(
     final req = ua_auth.AuthChallengeRequest(
       pubkey: pubkey,
       bootstrapToken: bootstrapToken,
-      keyType: switch (key.alg) {
-        KeyAlgorithm.rsa => ua_auth.KeyType.KEY_TYPE_RSA,
-        KeyAlgorithm.ecdsa => ua_auth.KeyType.KEY_TYPE_ECDSA_SECP256K1,
-        KeyAlgorithm.ed25519 => ua_auth.KeyType.KEY_TYPE_ED25519,
-      },
     );
     final response = await connection.ask(
       UserAgentRequest(auth: ua_auth.Request(challengeRequest: req)),
@@ -97,7 +93,10 @@ Future<Connection> connectAndAuthorize(
       );
     }
 
-    final challenge = _formatChallenge(authResponse.challenge, pubkey);
+    final challenge = await formatChallenge(
+      random: authResponse.challenge.random,
+      timestamp: authResponse.challenge.timestampNanos.toInt(),
+    );
     talker.info(
       'Received auth challenge, signing with key ${base64Encode(pubkey)}',
     );
@@ -106,7 +105,9 @@ Future<Connection> connectAndAuthorize(
     final solutionResponse = await connection.ask(
       UserAgentRequest(
         auth: ua_auth.Request(
-          challengeSolution: ua_auth.AuthChallengeSolution(signature: signature),
+          challengeSolution: ua_auth.AuthChallengeSolution(
+            signature: signature,
+          ),
         ),
       ),
     );
@@ -167,9 +168,3 @@ Future<Connection> _connect(StoredServerInfo serverInfo) async {
 
   return Connection(channel: channel, tx: tx, rx: rx);
 }
-
-List<int> _formatChallenge(ua_auth.AuthChallenge challenge, List<int> pubkey) {
-  final encodedPubkey = base64Encode(pubkey);
-  final payload = "${challenge.nonce}:$encodedPubkey";
-  return utf8.encode(payload);
-}

useragent/lib/features/connection/connection.dart

@@ -85,7 +85,9 @@ class Connection {
     if (response.hasId()) {
       final completer = _pendingRequests.remove(response.id);
       if (completer == null) {
-        talker.warning('Received response for unknown request id ${response.id}');
+        talker.warning(
+          'Received response for unknown request id ${response.id}',
+        );
         return;
       }
       completer.complete(response);

useragent/lib/features/connection/evm.dart

@@ -9,9 +9,7 @@ Future<List<WalletEntry>> listEvmWallets(Connection connection) async {
     UserAgentRequest(evm: ua_evm.Request(walletList: Empty())),
   );
   if (!response.hasEvm()) {
-    throw Exception(
-      'Expected EVM response, got ${response.whichPayload()}',
-    );
+    throw Exception('Expected EVM response, got ${response.whichPayload()}');
   }
 
   final evmResponse = response.evm;
@@ -37,9 +35,7 @@ Future<void> createEvmWallet(Connection connection) async {
     UserAgentRequest(evm: ua_evm.Request(walletCreate: Empty())),
   );
   if (!response.hasEvm()) {
-    throw Exception(
-      'Expected EVM response, got ${response.whichPayload()}',
-    );
+    throw Exception('Expected EVM response, got ${response.whichPayload()}');
   }
 
   final evmResponse = response.evm;

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

@@ -10,9 +10,7 @@ Future<List<GrantEntry>> listEvmGrants(Connection connection) async {
     UserAgentRequest(evm: ua_evm.Request(grantList: request)),
   );
   if (!response.hasEvm()) {
-    throw Exception(
-      'Expected EVM response, got ${response.whichPayload()}',
-    );
+    throw Exception('Expected EVM response, got ${response.whichPayload()}');
   }
 
   final evmResponse = response.evm;
@@ -50,9 +48,7 @@ Future<int> createEvmGrant(
   final resp = await connection.ask(request);
 
   if (!resp.hasEvm()) {
-    throw Exception(
-      'Expected EVM response, got ${resp.whichPayload()}',
-    );
+    throw Exception('Expected EVM response, got ${resp.whichPayload()}');
   }
 
   final evmResponse = resp.evm;
@@ -70,15 +66,11 @@ Future<int> createEvmGrant(
 Future<void> deleteEvmGrant(Connection connection, int grantId) async {
   final response = await connection.ask(
     UserAgentRequest(
-      evm: ua_evm.Request(
-        grantDelete: EvmGrantDeleteRequest(grantId: grantId),
-      ),
+      evm: ua_evm.Request(grantDelete: EvmGrantDeleteRequest(grantId: grantId)),
     ),
   );
   if (!response.hasEvm()) {
-    throw Exception(
-      'Expected EVM response, got ${response.whichPayload()}',
-    );
+    throw Exception('Expected EVM response, got ${response.whichPayload()}');
   }
 
   final evmResponse = response.evm;

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

@@ -8,9 +8,7 @@ Future<Set<int>> readClientWalletAccess(
   required int clientId,
 }) async {
   final response = await connection.ask(
-    UserAgentRequest(
-      sdkClient: ua_sdk.Request(listWalletAccess: Empty()),
-    ),
+    UserAgentRequest(sdkClient: ua_sdk.Request(listWalletAccess: Empty())),
   );
   if (!response.hasSdkClient()) {
     throw Exception(
@@ -33,9 +31,7 @@ Future<List<ua_sdk.WalletAccessEntry>> listAllWalletAccesses(
   Connection connection,
 ) async {
   final response = await connection.ask(
-    UserAgentRequest(
-      sdkClient: ua_sdk.Request(listWalletAccess: Empty()),
-    ),
+    UserAgentRequest(sdkClient: ua_sdk.Request(listWalletAccess: Empty())),
   );
   if (!response.hasSdkClient()) {
     throw Exception(
@@ -81,9 +77,7 @@ Future<void> writeClientWalletAccess(
       UserAgentRequest(
         sdkClient: ua_sdk.Request(
           revokeWalletAccess: ua_sdk.RevokeWalletAccess(
-            accesses: [
-              for (final walletId in toRevoke) walletId,
-            ],
+            accesses: [for (final walletId in toRevoke) walletId],
           ),
         ),
       ),

useragent/lib/features/connection/server_info_storage.dart

@@ -17,9 +17,9 @@ class StoredServerInfo {
   final int port;
   final String caCertFingerprint;
 
-  factory StoredServerInfo.fromJson(Map<String, dynamic> json) => _$StoredServerInfoFromJson(json);
+  factory StoredServerInfo.fromJson(Map<String, dynamic> json) =>
+      _$StoredServerInfoFromJson(json);
   Map<String, dynamic> toJson() => _$StoredServerInfoToJson(this);
-  
 }
 
 abstract class ServerInfoStorage {

useragent/lib/features/connection/vault.dart

@@ -1,5 +1,6 @@
 import 'package:arbiter/features/connection/connection.dart';
-import 'package:arbiter/proto/user_agent/vault/bootstrap.pb.dart' as ua_bootstrap;
+import 'package:arbiter/proto/user_agent/vault/bootstrap.pb.dart'
+    as ua_bootstrap;
 import 'package:arbiter/proto/user_agent/vault/unseal.pb.dart' as ua_unseal;
 import 'package:arbiter/proto/user_agent/vault/vault.pb.dart' as ua_vault;
 import 'package:arbiter/proto/user_agent.pb.dart';
@@ -27,9 +28,7 @@ Future<ua_bootstrap.BootstrapResult> bootstrapVault(
     ),
   );
   if (!response.hasVault()) {
-    throw Exception(
-      'Expected vault response, got ${response.whichPayload()}',
-    );
+    throw Exception('Expected vault response, got ${response.whichPayload()}');
   }
 
   final vaultResponse = response.vault;

useragent/lib/features/identity/hazmat_mldsa.dart

@@ -0,0 +1,71 @@
+import 'dart:convert';
+
+import 'package:arbiter/src/rust/api.dart';
+import 'package:cryptography/cryptography.dart';
+import 'package:flutter_secure_storage/flutter_secure_storage.dart';
+import 'package:arbiter/features/identity/pk_manager.dart';
+
+final storage = FlutterSecureStorage(
+  aOptions: AndroidOptions.biometric(
+    enforceBiometrics: true,
+    biometricPromptTitle: 'Authentication Required',
+  ),
+  mOptions: MacOsOptions(
+    accessibility: KeychainAccessibility.unlocked_this_device,
+    label: "Arbiter",
+    description: "Confirm your identity to access vault",
+    synchronizable: false,
+    accessControlFlags: [AccessControlFlag.userPresence],
+    usesDataProtectionKeychain: true,
+  ),
+);
+
+class HazmatMldsa extends KeyHandle {
+  final MldsaKey _key;
+
+  HazmatMldsa({required MldsaKey key}) : _key = key;
+
+  @override
+  Future<List<int>> getPublicKey() async {
+    final publicKey = await _key.getPublicKey();
+    return publicKey;
+  }
+
+  @override
+  Future<List<int>> sign(List<int> data) async {
+    final signature = await _key.sign(message: data);
+    return signature;
+  }
+}
+
+class HazmatMLDSAManager extends KeyManager {
+  static const _storageKey = "ed25519_identity";
+
+  @override
+  Future<KeyHandle> create() async {
+    final storedKey = await get();
+    if (storedKey != null) {
+      return storedKey;
+    }
+
+    final newKeypair = await MldsaKey.generate();
+    final keyBytes = await newKeypair.toBytes();
+
+    await storage.write(key: _storageKey, value: base64Encode(keyBytes));
+
+    return HazmatMldsa(key: newKeypair);
+  }
+
+  @override
+  Future<KeyHandle?> get() async {
+    final storedKeyPair = await storage.read(key: _storageKey);
+    if (storedKeyPair == null) {
+      return null;
+    }
+
+    final keyBytes = base64Decode(storedKeyPair);
+    final key = await MldsaKey.fromBytes(bytes: keyBytes);
+
+    return HazmatMldsa(key: key);
+  }
+}

useragent/lib/features/identity/pk_manager.dart

@@ -1,11 +1,6 @@
-enum KeyAlgorithm {
-  rsa, ecdsa, ed25519
-}
-
-// The API to handle without storing the private key in memory. 
+// The API to handle without storing the private key in memory.
 //The implementation will use platform-specific secure storage and signing capabilities.
 abstract class KeyHandle {
-  KeyAlgorithm get alg;
   Future<List<int>> sign(List<int> data);
   Future<List<int>> getPublicKey();
 }

useragent/lib/features/identity/simple_ed25519.dart

@@ -1,93 +0,0 @@
-import 'dart:convert';
-
-import 'package:cryptography/cryptography.dart';
-import 'package:flutter_secure_storage/flutter_secure_storage.dart';
-import 'package:arbiter/features/identity/pk_manager.dart';
-
-final storage = FlutterSecureStorage(
-  aOptions: AndroidOptions.biometric(
-    enforceBiometrics: true,
-    biometricPromptTitle: 'Authentication Required',
-  ),
-  mOptions: MacOsOptions(
-    accessibility: KeychainAccessibility.unlocked_this_device,
-    label: "Arbiter",
-    description: "Confirm your identity to access vault",
-    synchronizable: false,
-    accessControlFlags: [
-      AccessControlFlag.userPresence,
-    ],
-    usesDataProtectionKeychain: true,
-  ),
-);
-
-final processor = Ed25519();
-
-class SimpleEd25519 extends KeyHandle {
-  final SimpleKeyPair _keyPair;
-
-  SimpleEd25519({required SimpleKeyPair keyPair}) : _keyPair = keyPair;
-
-  @override
-  KeyAlgorithm get alg => KeyAlgorithm.ed25519;
-
-  @override
-  Future<List<int>> getPublicKey() async {
-    final publicKey = await _keyPair.extractPublicKey();
-    return publicKey.bytes;
-  }
-
-  @override
-  Future<List<int>> sign(List<int> data) async {
-    final signature = await processor.sign(data, keyPair: _keyPair);
-    return signature.bytes;
-  }
-}
-
-class SimpleEd25519Manager extends KeyManager {
-  static const _storageKey = "ed25519_identity";
-  static const _storagePublicKey = "ed25519_public_key";
-
-  @override
-  Future<KeyHandle> create() async {
-    final storedKey = await get();
-    if (storedKey != null) {
-      return storedKey;
-    }
-
-    final newKey = await processor.newKeyPair();
-    final rawKey = await newKey.extract();
-
-    final keyData = base64Encode(rawKey.bytes);
-    await storage.write(key: _storageKey, value: keyData);
-
-    final publicKeyData = base64Encode(rawKey.publicKey.bytes);
-    await storage.write(key: _storagePublicKey, value: publicKeyData);
-
-    return SimpleEd25519(keyPair: newKey);
-  }
-
-  @override
-  Future<KeyHandle?> get() async {
-    final storedKeyPair = await storage.read(key: _storageKey);
-    if (storedKeyPair == null) {
-      return null;
-    }
-
-    final publicKeyData = await storage.read(key: _storagePublicKey);
-    final publicKeyRaw = base64Decode(publicKeyData!);
-    final publicKey = SimplePublicKey(
-      publicKeyRaw,
-      type: processor.keyPairType,
-    );
-
-    final keyBytes = base64Decode(storedKeyPair);
-    final keypair = SimpleKeyPairData(
-      keyBytes,
-      publicKey: publicKey,
-      type: processor.keyPairType,
-    );
-
-    return SimpleEd25519(keyPair: keypair);
-  }
-}

useragent/lib/main.dart

@@ -1,10 +1,12 @@
 import 'package:arbiter/router.dart';
+import 'package:arbiter/src/rust/frb_generated.dart';
 import 'package:flutter/material.dart' hide Router;
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 import 'package:sizer/sizer.dart';
 
-void main() {
+Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
+  await RustLib.init();
   runApp(const ProviderScope(child: App()));
 }
 
@@ -33,3 +35,5 @@ class _AppState extends State<App> {
     );
   }
 }
+
+

useragent/lib/proto/client/auth.pb.dart

@@ -12,6 +12,7 @@
 
 import 'dart:core' as $core;
 
+import 'package:fixnum/fixnum.dart' as $fixnum;
 import 'package:protobuf/protobuf.dart' as $pb;
 
 import '../shared/client.pb.dart' as $0;
@@ -94,12 +95,12 @@ class AuthChallengeRequest extends $pb.GeneratedMessage {
 
 class AuthChallenge extends $pb.GeneratedMessage {
   factory AuthChallenge({
-    $core.List<$core.int>? pubkey,
-    $core.int? nonce,
+    $fixnum.Int64? timestampNanos,
+    $core.List<$core.int>? random,
   }) {
     final result = create();
-    if (pubkey != null) result.pubkey = pubkey;
-    if (nonce != null) result.nonce = nonce;
+    if (timestampNanos != null) result.timestampNanos = timestampNanos;
+    if (random != null) result.random = random;
     return result;
   }
 
@@ -117,9 +118,11 @@ class AuthChallenge extends $pb.GeneratedMessage {
       package:
           const $pb.PackageName(_omitMessageNames ? '' : 'arbiter.client.auth'),
       createEmptyInstance: create)
+    ..a<$fixnum.Int64>(
+        1, _omitFieldNames ? '' : 'timestampNanos', $pb.PbFieldType.OU6,
+        defaultOrMaker: $fixnum.Int64.ZERO)
     ..a<$core.List<$core.int>>(
-        1, _omitFieldNames ? '' : 'pubkey', $pb.PbFieldType.OY)
-    ..aI(2, _omitFieldNames ? '' : 'nonce')
+        2, _omitFieldNames ? '' : 'random', $pb.PbFieldType.OY)
     ..hasRequiredFields = false;
 
   @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
@@ -142,22 +145,22 @@ class AuthChallenge extends $pb.GeneratedMessage {
   static AuthChallenge? _defaultInstance;
 
   @$pb.TagNumber(1)
-  $core.List<$core.int> get pubkey => $_getN(0);
+  $fixnum.Int64 get timestampNanos => $_getI64(0);
   @$pb.TagNumber(1)
-  set pubkey($core.List<$core.int> value) => $_setBytes(0, value);
+  set timestampNanos($fixnum.Int64 value) => $_setInt64(0, value);
   @$pb.TagNumber(1)
-  $core.bool hasPubkey() => $_has(0);
+  $core.bool hasTimestampNanos() => $_has(0);
   @$pb.TagNumber(1)
-  void clearPubkey() => $_clearField(1);
+  void clearTimestampNanos() => $_clearField(1);
 
   @$pb.TagNumber(2)
-  $core.int get nonce => $_getIZ(1);
+  $core.List<$core.int> get random => $_getN(1);
   @$pb.TagNumber(2)
-  set nonce($core.int value) => $_setSignedInt32(1, value);
+  set random($core.List<$core.int> value) => $_setBytes(1, value);
   @$pb.TagNumber(2)
-  $core.bool hasNonce() => $_has(1);
+  $core.bool hasRandom() => $_has(1);
   @$pb.TagNumber(2)
-  void clearNonce() => $_clearField(2);
+  void clearRandom() => $_clearField(2);
 }
 
 class AuthChallengeSolution extends $pb.GeneratedMessage {

useragent/lib/proto/client/auth.pbjson.dart

@@ -62,15 +62,15 @@ final $typed_data.Uint8List authChallengeRequestDescriptor = $convert.base64Deco
 const AuthChallenge$json = {
   '1': 'AuthChallenge',
   '2': [
-    {'1': 'pubkey', '3': 1, '4': 1, '5': 12, '10': 'pubkey'},
-    {'1': 'nonce', '3': 2, '4': 1, '5': 5, '10': 'nonce'},
+    {'1': 'timestamp_nanos', '3': 1, '4': 1, '5': 4, '10': 'timestampNanos'},
+    {'1': 'random', '3': 2, '4': 1, '5': 12, '10': 'random'},
   ],
 };
 
 /// Descriptor for `AuthChallenge`. Decode as a `google.protobuf.DescriptorProto`.
 final $typed_data.Uint8List authChallengeDescriptor = $convert.base64Decode(
-    'Cg1BdXRoQ2hhbGxlbmdlEhYKBnB1YmtleRgBIAEoDFIGcHVia2V5EhQKBW5vbmNlGAIgASgFUg'
-    'Vub25jZQ==');
+    'Cg1BdXRoQ2hhbGxlbmdlEicKD3RpbWVzdGFtcF9uYW5vcxgBIAEoBFIOdGltZXN0YW1wTmFub3'
+    'MSFgoGcmFuZG9tGAIgASgMUgZyYW5kb20=');
 
 @$core.Deprecated('Use authChallengeSolutionDescriptor instead')
 const AuthChallengeSolution$json = {

useragent/lib/proto/shared/evm.pb.dart

@@ -414,6 +414,79 @@ class GasLimitExceededViolation extends $pb.GeneratedMessage {
   void clearMaxPriorityFeePerGas() => $_clearField(2);
 }
 
+class EvalViolation_ChainIdMismatch extends $pb.GeneratedMessage {
+  factory EvalViolation_ChainIdMismatch({
+    $fixnum.Int64? expected,
+    $fixnum.Int64? actual,
+  }) {
+    final result = create();
+    if (expected != null) result.expected = expected;
+    if (actual != null) result.actual = actual;
+    return result;
+  }
+
+  EvalViolation_ChainIdMismatch._();
+
+  factory EvalViolation_ChainIdMismatch.fromBuffer($core.List<$core.int> data,
+          [$pb.ExtensionRegistry registry = $pb.ExtensionRegistry.EMPTY]) =>
+      create()..mergeFromBuffer(data, registry);
+  factory EvalViolation_ChainIdMismatch.fromJson($core.String json,
+          [$pb.ExtensionRegistry registry = $pb.ExtensionRegistry.EMPTY]) =>
+      create()..mergeFromJson(json, registry);
+
+  static final $pb.BuilderInfo _i = $pb.BuilderInfo(
+      _omitMessageNames ? '' : 'EvalViolation.ChainIdMismatch',
+      package:
+          const $pb.PackageName(_omitMessageNames ? '' : 'arbiter.shared.evm'),
+      createEmptyInstance: create)
+    ..a<$fixnum.Int64>(
+        1, _omitFieldNames ? '' : 'expected', $pb.PbFieldType.OU6,
+        defaultOrMaker: $fixnum.Int64.ZERO)
+    ..a<$fixnum.Int64>(2, _omitFieldNames ? '' : 'actual', $pb.PbFieldType.OU6,
+        defaultOrMaker: $fixnum.Int64.ZERO)
+    ..hasRequiredFields = false;
+
+  @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
+  EvalViolation_ChainIdMismatch clone() => deepCopy();
+  @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
+  EvalViolation_ChainIdMismatch copyWith(
+          void Function(EvalViolation_ChainIdMismatch) updates) =>
+      super.copyWith(
+              (message) => updates(message as EvalViolation_ChainIdMismatch))
+          as EvalViolation_ChainIdMismatch;
+
+  @$core.override
+  $pb.BuilderInfo get info_ => _i;
+
+  @$core.pragma('dart2js:noInline')
+  static EvalViolation_ChainIdMismatch create() =>
+      EvalViolation_ChainIdMismatch._();
+  @$core.override
+  EvalViolation_ChainIdMismatch createEmptyInstance() => create();
+  @$core.pragma('dart2js:noInline')
+  static EvalViolation_ChainIdMismatch getDefault() => _defaultInstance ??=
+      $pb.GeneratedMessage.$_defaultFor<EvalViolation_ChainIdMismatch>(create);
+  static EvalViolation_ChainIdMismatch? _defaultInstance;
+
+  @$pb.TagNumber(1)
+  $fixnum.Int64 get expected => $_getI64(0);
+  @$pb.TagNumber(1)
+  set expected($fixnum.Int64 value) => $_setInt64(0, value);
+  @$pb.TagNumber(1)
+  $core.bool hasExpected() => $_has(0);
+  @$pb.TagNumber(1)
+  void clearExpected() => $_clearField(1);
+
+  @$pb.TagNumber(2)
+  $fixnum.Int64 get actual => $_getI64(1);
+  @$pb.TagNumber(2)
+  set actual($fixnum.Int64 value) => $_setInt64(1, value);
+  @$pb.TagNumber(2)
+  $core.bool hasActual() => $_has(1);
+  @$pb.TagNumber(2)
+  void clearActual() => $_clearField(2);
+}
+
 enum EvalViolation_Kind {
   invalidTarget,
   gasLimitExceeded,
@@ -421,6 +494,7 @@ enum EvalViolation_Kind {
   volumetricLimitExceeded,
   invalidTime,
   invalidTransactionType,
+  chainIdMismatch,
   notSet
 }
 
@@ -432,6 +506,7 @@ class EvalViolation extends $pb.GeneratedMessage {
     $0.Empty? volumetricLimitExceeded,
     $0.Empty? invalidTime,
     $0.Empty? invalidTransactionType,
+    EvalViolation_ChainIdMismatch? chainIdMismatch,
   }) {
     final result = create();
     if (invalidTarget != null) result.invalidTarget = invalidTarget;
@@ -442,6 +517,7 @@ class EvalViolation extends $pb.GeneratedMessage {
     if (invalidTime != null) result.invalidTime = invalidTime;
     if (invalidTransactionType != null)
       result.invalidTransactionType = invalidTransactionType;
+    if (chainIdMismatch != null) result.chainIdMismatch = chainIdMismatch;
     return result;
   }
 
@@ -462,6 +538,7 @@ class EvalViolation extends $pb.GeneratedMessage {
     4: EvalViolation_Kind.volumetricLimitExceeded,
     5: EvalViolation_Kind.invalidTime,
     6: EvalViolation_Kind.invalidTransactionType,
+    7: EvalViolation_Kind.chainIdMismatch,
     0: EvalViolation_Kind.notSet
   };
   static final $pb.BuilderInfo _i = $pb.BuilderInfo(
@@ -469,7 +546,7 @@ class EvalViolation extends $pb.GeneratedMessage {
       package:
           const $pb.PackageName(_omitMessageNames ? '' : 'arbiter.shared.evm'),
       createEmptyInstance: create)
-    ..oo(0, [1, 2, 3, 4, 5, 6])
+    ..oo(0, [1, 2, 3, 4, 5, 6, 7])
     ..a<$core.List<$core.int>>(
         1, _omitFieldNames ? '' : 'invalidTarget', $pb.PbFieldType.OY)
     ..aOM<GasLimitExceededViolation>(
@@ -483,6 +560,9 @@ class EvalViolation extends $pb.GeneratedMessage {
         subBuilder: $0.Empty.create)
     ..aOM<$0.Empty>(6, _omitFieldNames ? '' : 'invalidTransactionType',
         subBuilder: $0.Empty.create)
+    ..aOM<EvalViolation_ChainIdMismatch>(
+        7, _omitFieldNames ? '' : 'chainIdMismatch',
+        subBuilder: EvalViolation_ChainIdMismatch.create)
     ..hasRequiredFields = false;
 
   @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
@@ -510,6 +590,7 @@ class EvalViolation extends $pb.GeneratedMessage {
   @$pb.TagNumber(4)
   @$pb.TagNumber(5)
   @$pb.TagNumber(6)
+  @$pb.TagNumber(7)
   EvalViolation_Kind whichKind() => _EvalViolation_KindByTag[$_whichOneof(0)]!;
   @$pb.TagNumber(1)
   @$pb.TagNumber(2)
@@ -517,6 +598,7 @@ class EvalViolation extends $pb.GeneratedMessage {
   @$pb.TagNumber(4)
   @$pb.TagNumber(5)
   @$pb.TagNumber(6)
+  @$pb.TagNumber(7)
   void clearKind() => $_clearField($_whichOneof(0));
 
   @$pb.TagNumber(1)
@@ -582,6 +664,18 @@ class EvalViolation extends $pb.GeneratedMessage {
   void clearInvalidTransactionType() => $_clearField(6);
   @$pb.TagNumber(6)
   $0.Empty ensureInvalidTransactionType() => $_ensure(5);
+
+  @$pb.TagNumber(7)
+  EvalViolation_ChainIdMismatch get chainIdMismatch => $_getN(6);
+  @$pb.TagNumber(7)
+  set chainIdMismatch(EvalViolation_ChainIdMismatch value) =>
+      $_setField(7, value);
+  @$pb.TagNumber(7)
+  $core.bool hasChainIdMismatch() => $_has(6);
+  @$pb.TagNumber(7)
+  void clearChainIdMismatch() => $_clearField(7);
+  @$pb.TagNumber(7)
+  EvalViolation_ChainIdMismatch ensureChainIdMismatch() => $_ensure(6);
 }
 
 /// Transaction was classified but no grant covers it

useragent/lib/proto/shared/evm.pbjson.dart

@@ -195,12 +195,31 @@ const EvalViolation$json = {
       '9': 0,
       '10': 'invalidTransactionType'
     },
+    {
+      '1': 'chain_id_mismatch',
+      '3': 7,
+      '4': 1,
+      '5': 11,
+      '6': '.arbiter.shared.evm.EvalViolation.ChainIdMismatch',
+      '9': 0,
+      '10': 'chainIdMismatch'
+    },
   ],
+  '3': [EvalViolation_ChainIdMismatch$json],
   '8': [
     {'1': 'kind'},
   ],
 };
 
+@$core.Deprecated('Use evalViolationDescriptor instead')
+const EvalViolation_ChainIdMismatch$json = {
+  '1': 'ChainIdMismatch',
+  '2': [
+    {'1': 'expected', '3': 1, '4': 1, '5': 4, '10': 'expected'},
+    {'1': 'actual', '3': 2, '4': 1, '5': 4, '10': 'actual'},
+  ],
+};
+
 /// Descriptor for `EvalViolation`. Decode as a `google.protobuf.DescriptorProto`.
 final $typed_data.Uint8List evalViolationDescriptor = $convert.base64Decode(
     'Cg1FdmFsVmlvbGF0aW9uEicKDmludmFsaWRfdGFyZ2V0GAEgASgMSABSDWludmFsaWRUYXJnZX'
@@ -211,7 +230,10 @@ final $typed_data.Uint8List evalViolationDescriptor = $convert.base64Decode(
     'YuRW1wdHlIAFIXdm9sdW1ldHJpY0xpbWl0RXhjZWVkZWQSOwoMaW52YWxpZF90aW1lGAUgASgL'
     'MhYuZ29vZ2xlLnByb3RvYnVmLkVtcHR5SABSC2ludmFsaWRUaW1lElIKGGludmFsaWRfdHJhbn'
     'NhY3Rpb25fdHlwZRgGIAEoCzIWLmdvb2dsZS5wcm90b2J1Zi5FbXB0eUgAUhZpbnZhbGlkVHJh'
-    'bnNhY3Rpb25UeXBlQgYKBGtpbmQ=');
+    'bnNhY3Rpb25UeXBlEl8KEWNoYWluX2lkX21pc21hdGNoGAcgASgLMjEuYXJiaXRlci5zaGFyZW'
+    'QuZXZtLkV2YWxWaW9sYXRpb24uQ2hhaW5JZE1pc21hdGNoSABSD2NoYWluSWRNaXNtYXRjaBpF'
+    'Cg9DaGFpbklkTWlzbWF0Y2gSGgoIZXhwZWN0ZWQYASABKARSCGV4cGVjdGVkEhYKBmFjdHVhbB'
+    'gCIAEoBFIGYWN0dWFsQgYKBGtpbmQ=');
 
 @$core.Deprecated('Use noMatchingGrantErrorDescriptor instead')
 const NoMatchingGrantError$json = {

useragent/lib/proto/user_agent/auth.pb.dart

@@ -12,6 +12,7 @@
 
 import 'dart:core' as $core;
 
+import 'package:fixnum/fixnum.dart' as $fixnum;
 import 'package:protobuf/protobuf.dart' as $pb;
 
 import 'auth.pbenum.dart';
@@ -24,12 +25,10 @@ class AuthChallengeRequest extends $pb.GeneratedMessage {
   factory AuthChallengeRequest({
     $core.List<$core.int>? pubkey,
     $core.String? bootstrapToken,
-    KeyType? keyType,
   }) {
     final result = create();
     if (pubkey != null) result.pubkey = pubkey;
     if (bootstrapToken != null) result.bootstrapToken = bootstrapToken;
-    if (keyType != null) result.keyType = keyType;
     return result;
   }
 
@@ -50,8 +49,6 @@ class AuthChallengeRequest extends $pb.GeneratedMessage {
     ..a<$core.List<$core.int>>(
         1, _omitFieldNames ? '' : 'pubkey', $pb.PbFieldType.OY)
     ..aOS(2, _omitFieldNames ? '' : 'bootstrapToken')
-    ..aE<KeyType>(3, _omitFieldNames ? '' : 'keyType',
-        enumValues: KeyType.values)
     ..hasRequiredFields = false;
 
   @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
@@ -90,23 +87,16 @@ class AuthChallengeRequest extends $pb.GeneratedMessage {
   $core.bool hasBootstrapToken() => $_has(1);
   @$pb.TagNumber(2)
   void clearBootstrapToken() => $_clearField(2);
-
-  @$pb.TagNumber(3)
-  KeyType get keyType => $_getN(2);
-  @$pb.TagNumber(3)
-  set keyType(KeyType value) => $_setField(3, value);
-  @$pb.TagNumber(3)
-  $core.bool hasKeyType() => $_has(2);
-  @$pb.TagNumber(3)
-  void clearKeyType() => $_clearField(3);
 }
 
 class AuthChallenge extends $pb.GeneratedMessage {
   factory AuthChallenge({
-    $core.int? nonce,
+    $fixnum.Int64? timestampNanos,
+    $core.List<$core.int>? random,
   }) {
     final result = create();
-    if (nonce != null) result.nonce = nonce;
+    if (timestampNanos != null) result.timestampNanos = timestampNanos;
+    if (random != null) result.random = random;
     return result;
   }
 
@@ -124,7 +114,11 @@ class AuthChallenge extends $pb.GeneratedMessage {
       package: const $pb.PackageName(
           _omitMessageNames ? '' : 'arbiter.user_agent.auth'),
       createEmptyInstance: create)
-    ..aI(1, _omitFieldNames ? '' : 'nonce')
+    ..a<$fixnum.Int64>(
+        1, _omitFieldNames ? '' : 'timestampNanos', $pb.PbFieldType.OU6,
+        defaultOrMaker: $fixnum.Int64.ZERO)
+    ..a<$core.List<$core.int>>(
+        2, _omitFieldNames ? '' : 'random', $pb.PbFieldType.OY)
     ..hasRequiredFields = false;
 
   @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
@@ -147,13 +141,22 @@ class AuthChallenge extends $pb.GeneratedMessage {
   static AuthChallenge? _defaultInstance;
 
   @$pb.TagNumber(1)
-  $core.int get nonce => $_getIZ(0);
+  $fixnum.Int64 get timestampNanos => $_getI64(0);
   @$pb.TagNumber(1)
-  set nonce($core.int value) => $_setSignedInt32(0, value);
+  set timestampNanos($fixnum.Int64 value) => $_setInt64(0, value);
   @$pb.TagNumber(1)
-  $core.bool hasNonce() => $_has(0);
+  $core.bool hasTimestampNanos() => $_has(0);
   @$pb.TagNumber(1)
-  void clearNonce() => $_clearField(1);
+  void clearTimestampNanos() => $_clearField(1);
+
+  @$pb.TagNumber(2)
+  $core.List<$core.int> get random => $_getN(1);
+  @$pb.TagNumber(2)
+  set random($core.List<$core.int> value) => $_setBytes(1, value);
+  @$pb.TagNumber(2)
+  $core.bool hasRandom() => $_has(1);
+  @$pb.TagNumber(2)
+  void clearRandom() => $_clearField(2);
 }
 
 class AuthChallengeSolution extends $pb.GeneratedMessage {

useragent/lib/proto/user_agent/auth.pbenum.dart

@@ -14,31 +14,6 @@ import 'dart:core' as $core;
 
 import 'package:protobuf/protobuf.dart' as $pb;
 
-class KeyType extends $pb.ProtobufEnum {
-  static const KeyType KEY_TYPE_UNSPECIFIED =
-      KeyType._(0, _omitEnumNames ? '' : 'KEY_TYPE_UNSPECIFIED');
-  static const KeyType KEY_TYPE_ED25519 =
-      KeyType._(1, _omitEnumNames ? '' : 'KEY_TYPE_ED25519');
-  static const KeyType KEY_TYPE_ECDSA_SECP256K1 =
-      KeyType._(2, _omitEnumNames ? '' : 'KEY_TYPE_ECDSA_SECP256K1');
-  static const KeyType KEY_TYPE_RSA =
-      KeyType._(3, _omitEnumNames ? '' : 'KEY_TYPE_RSA');
-
-  static const $core.List<KeyType> values = <KeyType>[
-    KEY_TYPE_UNSPECIFIED,
-    KEY_TYPE_ED25519,
-    KEY_TYPE_ECDSA_SECP256K1,
-    KEY_TYPE_RSA,
-  ];
-
-  static final $core.List<KeyType?> _byValue =
-      $pb.ProtobufEnum.$_initByValueList(values, 3);
-  static KeyType? valueOf($core.int value) =>
-      value < 0 || value >= _byValue.length ? null : _byValue[value];
-
-  const KeyType._(super.value, super.name);
-}
-
 class AuthResult extends $pb.ProtobufEnum {
   static const AuthResult AUTH_RESULT_UNSPECIFIED =
       AuthResult._(0, _omitEnumNames ? '' : 'AUTH_RESULT_UNSPECIFIED');

useragent/lib/proto/user_agent/auth.pbjson.dart

@@ -15,22 +15,6 @@ import 'dart:convert' as $convert;
 import 'dart:core' as $core;
 import 'dart:typed_data' as $typed_data;
 
-@$core.Deprecated('Use keyTypeDescriptor instead')
-const KeyType$json = {
-  '1': 'KeyType',
-  '2': [
-    {'1': 'KEY_TYPE_UNSPECIFIED', '2': 0},
-    {'1': 'KEY_TYPE_ED25519', '2': 1},
-    {'1': 'KEY_TYPE_ECDSA_SECP256K1', '2': 2},
-    {'1': 'KEY_TYPE_RSA', '2': 3},
-  ],
-};
-
-/// Descriptor for `KeyType`. Decode as a `google.protobuf.EnumDescriptorProto`.
-final $typed_data.Uint8List keyTypeDescriptor = $convert.base64Decode(
-    'CgdLZXlUeXBlEhgKFEtFWV9UWVBFX1VOU1BFQ0lGSUVEEAASFAoQS0VZX1RZUEVfRUQyNTUxOR'
-    'ABEhwKGEtFWV9UWVBFX0VDRFNBX1NFQ1AyNTZLMRACEhAKDEtFWV9UWVBFX1JTQRAD');
-
 @$core.Deprecated('Use authResultDescriptor instead')
 const AuthResult$json = {
   '1': 'AuthResult',
@@ -67,14 +51,6 @@ const AuthChallengeRequest$json = {
       '10': 'bootstrapToken',
       '17': true
     },
-    {
-      '1': 'key_type',
-      '3': 3,
-      '4': 1,
-      '5': 14,
-      '6': '.arbiter.user_agent.auth.KeyType',
-      '10': 'keyType'
-    },
   ],
   '8': [
     {'1': '_bootstrap_token'},
@@ -84,21 +60,22 @@ const AuthChallengeRequest$json = {
 /// Descriptor for `AuthChallengeRequest`. Decode as a `google.protobuf.DescriptorProto`.
 final $typed_data.Uint8List authChallengeRequestDescriptor = $convert.base64Decode(
     'ChRBdXRoQ2hhbGxlbmdlUmVxdWVzdBIWCgZwdWJrZXkYASABKAxSBnB1YmtleRIsCg9ib290c3'
-    'RyYXBfdG9rZW4YAiABKAlIAFIOYm9vdHN0cmFwVG9rZW6IAQESOwoIa2V5X3R5cGUYAyABKA4y'
-    'IC5hcmJpdGVyLnVzZXJfYWdlbnQuYXV0aC5LZXlUeXBlUgdrZXlUeXBlQhIKEF9ib290c3RyYX'
-    'BfdG9rZW4=');
+    'RyYXBfdG9rZW4YAiABKAlIAFIOYm9vdHN0cmFwVG9rZW6IAQFCEgoQX2Jvb3RzdHJhcF90b2tl'
+    'bg==');
 
 @$core.Deprecated('Use authChallengeDescriptor instead')
 const AuthChallenge$json = {
   '1': 'AuthChallenge',
   '2': [
-    {'1': 'nonce', '3': 1, '4': 1, '5': 5, '10': 'nonce'},
+    {'1': 'timestamp_nanos', '3': 1, '4': 1, '5': 4, '10': 'timestampNanos'},
+    {'1': 'random', '3': 2, '4': 1, '5': 12, '10': 'random'},
   ],
 };
 
 /// Descriptor for `AuthChallenge`. Decode as a `google.protobuf.DescriptorProto`.
-final $typed_data.Uint8List authChallengeDescriptor = $convert
-    .base64Decode('Cg1BdXRoQ2hhbGxlbmdlEhQKBW5vbmNlGAEgASgFUgVub25jZQ==');
+final $typed_data.Uint8List authChallengeDescriptor = $convert.base64Decode(
+    'Cg1BdXRoQ2hhbGxlbmdlEicKD3RpbWVzdGFtcF9uYW5vcxgBIAEoBFIOdGltZXN0YW1wTmFub3'
+    'MSFgoGcmFuZG9tGAIgASgMUgZyYW5kb20=');
 
 @$core.Deprecated('Use authChallengeSolutionDescriptor instead')
 const AuthChallengeSolution$json = {

useragent/lib/providers/connection/bootstrap_token.dart

@@ -1,5 +1,3 @@
-
-
 import 'package:riverpod_annotation/riverpod_annotation.dart';
 
 part 'bootstrap_token.g.dart';

useragent/lib/providers/evm/evm.dart

@@ -2,7 +2,6 @@ import 'package:arbiter/features/connection/evm.dart' as evm;
 import 'package:arbiter/proto/evm.pb.dart';
 import 'package:arbiter/providers/connection/connection_manager.dart';
 import 'package:hooks_riverpod/experimental/mutation.dart';
-import 'package:hooks_riverpod/hooks_riverpod.dart';
 import 'package:riverpod_annotation/riverpod_annotation.dart';
 
 part 'evm.g.dart';
@@ -35,7 +34,7 @@ final createEvmWallet = Mutation();
 
 Future<void> executeCreateEvmWallet(MutationTarget target) async {
   return await createEvmWallet.run(target, (tsx) async {
-       final connection = await tsx.get(connectionManagerProvider.future);
+    final connection = await tsx.get(connectionManagerProvider.future);
     if (connection == null) {
       throw Exception('Not connected to the server.');
     }
@@ -44,4 +43,4 @@ Future<void> executeCreateEvmWallet(MutationTarget target) async {
 
     await tsx.get(evmProvider.notifier).refreshWallets();
   });
-}
+}

useragent/lib/providers/key.dart

@@ -1,13 +1,13 @@
 import 'package:mtcore/markettakers.dart';
 import 'package:riverpod_annotation/riverpod_annotation.dart';
 import 'package:arbiter/features/identity/pk_manager.dart';
-import 'package:arbiter/features/identity/simple_ed25519.dart';
+import 'package:arbiter/features/identity/hazmat_mldsa.dart';
 
 part 'key.g.dart';
 
 @riverpod
 KeyManager keyManager(Ref ref) {
-  return SimpleEd25519Manager();
+  return HazmatMLDSAManager();
 }
 
 @Riverpod(keepAlive: true)

useragent/lib/providers/sdk_clients/list.dart

@@ -18,9 +18,7 @@ Future<List<ua_sdk.Entry>?> sdkClients(Ref ref) async {
   );
 
   if (!resp.hasSdkClient()) {
-    throw Exception(
-      'Expected SDK client response, got ${resp.whichPayload()}',
-    );
+    throw Exception('Expected SDK client response, got ${resp.whichPayload()}');
   }
   final sdkClientResponse = resp.sdkClient;
   if (!sdkClientResponse.hasList()) {

useragent/lib/providers/server_info.dart

@@ -46,6 +46,8 @@ class ServerInfo extends _$ServerInfo {
 
   Future<String> _fingerprint(List<int> caCert) async {
     final digest = await Sha256().hash(caCert);
-    return digest.bytes.map((byte) => byte.toRadixString(16).padLeft(2, '0')).join();
+    return digest.bytes
+        .map((byte) => byte.toRadixString(16).padLeft(2, '0'))
+        .join();
   }
 }

useragent/lib/screens/callouts/sdk_connect.dart

@@ -28,8 +28,7 @@ class SdkConnectCallout extends StatelessWidget {
 
     final hasDescription =
         clientInfo.hasDescription() && clientInfo.description.isNotEmpty;
-    final hasVersion =
-        clientInfo.hasVersion() && clientInfo.version.isNotEmpty;
+    final hasVersion = clientInfo.hasVersion() && clientInfo.version.isNotEmpty;
     final showInfoCard = hasDescription || hasVersion;
 
     return CreamFrame(
@@ -74,10 +73,7 @@ class SdkConnectCallout extends StatelessWidget {
                 borderRadius: BorderRadius.circular(14),
                 border: Border.all(color: Palette.line),
               ),
-              padding: EdgeInsets.symmetric(
-                horizontal: 1.6.w,
-                vertical: 1.2.h,
-              ),
+              padding: EdgeInsets.symmetric(horizontal: 1.6.w, vertical: 1.2.h),
               child: Column(
                 crossAxisAlignment: CrossAxisAlignment.start,
                 spacing: 0.6.h,

useragent/lib/screens/dashboard.dart

@@ -78,7 +78,7 @@ class DashboardRouter extends StatelessWidget {
 }
 
 class _CalloutBell extends ConsumerWidget {
-  const _CalloutBell({super.key});
+  const _CalloutBell();
 
   @override
   Widget build(BuildContext context, WidgetRef ref) {

useragent/lib/screens/dashboard/clients/details.dart

@@ -1,4 +1,3 @@
-
 import 'package:arbiter/proto/user_agent/sdk_client.pb.dart' as ua_sdk;
 import 'package:auto_route/auto_route.dart';
 import 'package:flutter/material.dart';
@@ -13,5 +12,4 @@ class ClientDetails extends ConsumerWidget {
   Widget build(BuildContext context, WidgetRef ref) {
     throw UnimplementedError();
   }
-
 }

useragent/lib/screens/dashboard/clients/details/widgets/client_summary_card.dart

@@ -12,30 +12,24 @@ class ClientSummaryCard extends StatelessWidget {
     return CreamFrame(
       padding: const EdgeInsets.all(20),
       child: Column(
-          crossAxisAlignment: CrossAxisAlignment.start,
-          children: [
-            Text(
-              client.info.name,
-              style: Theme.of(context).textTheme.titleLarge,
-            ),
-            const SizedBox(height: 8),
-            Text(client.info.description),
-            const SizedBox(height: 16),
-            Wrap(
-              runSpacing: 8,
-              spacing: 16,
-              children: [
-                _Fact(label: 'Client ID', value: '${client.id}'),
-                _Fact(label: 'Version', value: client.info.version),
-                _Fact(
-                  label: 'Registered',
-                  value: _formatDate(client.createdAt),
-                ),
-                _Fact(label: 'Pubkey', value: _shortPubkey(client.pubkey)),
-              ],
-            ),
-          ],
-        ),
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          Text(client.info.name, style: Theme.of(context).textTheme.titleLarge),
+          const SizedBox(height: 8),
+          Text(client.info.description),
+          const SizedBox(height: 16),
+          Wrap(
+            runSpacing: 8,
+            spacing: 16,
+            children: [
+              _Fact(label: 'Client ID', value: '${client.id}'),
+              _Fact(label: 'Version', value: client.info.version),
+              _Fact(label: 'Registered', value: _formatDate(client.createdAt)),
+              _Fact(label: 'Pubkey', value: _shortPubkey(client.pubkey)),
+            ],
+          ),
+        ],
+      ),
     );
   }
 }

useragent/lib/screens/dashboard/clients/details/widgets/wallet_access_save_bar.dart

@@ -28,27 +28,27 @@ class WalletAccessSaveBar extends StatelessWidget {
     return CreamFrame(
       padding: const EdgeInsets.all(16),
       child: Column(
-          crossAxisAlignment: CrossAxisAlignment.start,
-          children: [
-            if (errorText != null) ...[
-              Text(errorText, style: TextStyle(color: Palette.coral)),
-              const SizedBox(height: 12),
-            ],
-            Row(
-              children: [
-                TextButton(
-                  onPressed: state.hasChanges && !isPending ? onDiscard : null,
-                  child: const Text('Reset'),
-                ),
-                const Spacer(),
-                FilledButton(
-                  onPressed: state.hasChanges && !isPending ? onSave : null,
-                  child: Text(isPending ? 'Saving...' : 'Save changes'),
-                ),
-              ],
-            ),
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          if (errorText != null) ...[
+            Text(errorText, style: TextStyle(color: Palette.coral)),
+            const SizedBox(height: 12),
           ],
-        ),
+          Row(
+            children: [
+              TextButton(
+                onPressed: state.hasChanges && !isPending ? onDiscard : null,
+                child: const Text('Reset'),
+              ),
+              const Spacer(),
+              FilledButton(
+                onPressed: state.hasChanges && !isPending ? onSave : null,
+                child: Text(isPending ? 'Saving...' : 'Save changes'),
+              ),
+            ],
+          ),
+        ],
+      ),
     );
   }
 }

useragent/lib/screens/dashboard/clients/details/widgets/wallet_access_section.dart

@@ -30,26 +30,23 @@ class WalletAccessSection extends ConsumerWidget {
     return CreamFrame(
       padding: const EdgeInsets.all(20),
       child: Column(
-          crossAxisAlignment: CrossAxisAlignment.start,
-          children: [
-            Text(
-              'Wallet access',
-              style: Theme.of(context).textTheme.titleLarge,
-            ),
-            const SizedBox(height: 8),
-            Text('Choose which managed wallets this client can see.'),
-            const SizedBox(height: 16),
-            _WalletAccessBody(
-              clientId: clientId,
-              state: state,
-              accessSelectionAsync: accessSelectionAsync,
-              isSavePending: isSavePending,
-              optionsAsync: optionsAsync,
-              onSearchChanged: onSearchChanged,
-              onToggleWallet: onToggleWallet,
-            ),
-          ],
-        ),
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          Text('Wallet access', style: Theme.of(context).textTheme.titleLarge),
+          const SizedBox(height: 8),
+          Text('Choose which managed wallets this client can see.'),
+          const SizedBox(height: 16),
+          _WalletAccessBody(
+            clientId: clientId,
+            state: state,
+            accessSelectionAsync: accessSelectionAsync,
+            isSavePending: isSavePending,
+            optionsAsync: optionsAsync,
+            onSearchChanged: onSearchChanged,
+            onToggleWallet: onToggleWallet,
+          ),
+        ],
+      ),
     );
   }
 }

useragent/lib/screens/dashboard/clients/table.dart

@@ -378,48 +378,48 @@ class _ClientTable extends StatelessWidget {
         builder: (context, constraints) {
           final tableWidth = math.max(_tableMinWidth, constraints.maxWidth);
 
-            return Column(
-              crossAxisAlignment: CrossAxisAlignment.start,
-              children: [
-                Text(
-                  'Registered clients',
-                  style: theme.textTheme.titleLarge?.copyWith(
-                    color: Palette.ink,
-                    fontWeight: FontWeight.w800,
-                  ),
+          return Column(
+            crossAxisAlignment: CrossAxisAlignment.start,
+            children: [
+              Text(
+                'Registered clients',
+                style: theme.textTheme.titleLarge?.copyWith(
+                  color: Palette.ink,
+                  fontWeight: FontWeight.w800,
                 ),
-                SizedBox(height: 0.6.h),
-                Text(
-                  'Every entry here has authenticated with Arbiter at least once.',
-                  style: theme.textTheme.bodyMedium?.copyWith(
-                    color: Palette.ink.withValues(alpha: 0.70),
-                    height: 1.4,
-                  ),
+              ),
+              SizedBox(height: 0.6.h),
+              Text(
+                'Every entry here has authenticated with Arbiter at least once.',
+                style: theme.textTheme.bodyMedium?.copyWith(
+                  color: Palette.ink.withValues(alpha: 0.70),
+                  height: 1.4,
                 ),
-                SizedBox(height: 1.6.h),
-                SingleChildScrollView(
-                  scrollDirection: Axis.horizontal,
-                  child: SizedBox(
-                    width: tableWidth,
-                    child: Column(
-                      children: [
-                        const _ClientTableHeader(),
-                        SizedBox(height: 1.h),
-                        for (var i = 0; i < clients.length; i++)
-                          Padding(
-                            padding: EdgeInsets.only(
-                              bottom: i == clients.length - 1 ? 0 : 1.h,
-                            ),
-                            child: _ClientTableRow(client: clients[i]),
+              ),
+              SizedBox(height: 1.6.h),
+              SingleChildScrollView(
+                scrollDirection: Axis.horizontal,
+                child: SizedBox(
+                  width: tableWidth,
+                  child: Column(
+                    children: [
+                      const _ClientTableHeader(),
+                      SizedBox(height: 1.h),
+                      for (var i = 0; i < clients.length; i++)
+                        Padding(
+                          padding: EdgeInsets.only(
+                            bottom: i == clients.length - 1 ? 0 : 1.h,
                           ),
-                      ],
-                    ),
+                          child: _ClientTableRow(client: clients[i]),
+                        ),
+                    ],
                   ),
                 ),
-              ],
-            );
-          },
-        ),
+              ),
+            ],
+          );
+        },
+      ),
     );
   }
 }

useragent/lib/screens/dashboard/evm/grants/create/fields/client_picker_field.dart

@@ -31,7 +31,9 @@ class ClientPickerField extends ConsumerWidget {
           ? null
           : (value) {
               ref.read(grantCreationProvider.notifier).setClientId(value);
-              FormBuilder.of(context)?.fields['walletAccessId']?.didChange(null);
+              FormBuilder.of(
+                context,
+              )?.fields['walletAccessId']?.didChange(null);
             },
     );
   }