merge: refactor-integrity-check into main

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

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

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

@@ -1,4 +1,3 @@
-use crate::actors::keyholder;
 use arbiter_crypto::hashing::Hashable;
 use hmac::Hmac;
 use sha2::Sha256;
@@ -9,7 +8,7 @@ use kameo::{actor::ActorRef, error::SendError};
 use sha2::Digest as _;
 
 use crate::{
-    actors::keyholder::{KeyHolder, SignIntegrity, VerifyIntegrity},
+    actors::vault::{self, GetState, SignIntegrity, Vault, VerifyIntegrity},
     db::{
         self,
         models::{IntegrityEnvelope, NewIntegrityEnvelope},
@@ -22,11 +21,11 @@ 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 },
@@ -103,7 +102,7 @@ impl IntoId for &'_ [u8] {
 
 pub async fn sign_entity<E: Integrable>(
     conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
     entity: &E,
     entity_id: impl IntoId,
 ) -> Result<(), Error> {
@@ -113,13 +112,14 @@ 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 {
@@ -148,7 +148,7 @@ pub async fn sign_entity<E: Integrable>(
 
 pub async fn verify_entity<E: Integrable>(
     conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
     entity: &E,
     entity_id: impl IntoId,
 ) -> Result<AttestationStatus, Error> {
@@ -176,7 +176,7 @@ pub async fn verify_entity<E: Integrable>(
     let payload_hash = payload_hash(&entity);
     let mac_input = build_mac_input(E::KIND, &entity_id, envelope.payload_version, &payload_hash);
 
-    let result = keyholder
+    let result = vault
         .ask(VerifyIntegrity {
             mac_input,
             expected_mac: envelope.mac,
@@ -189,13 +189,16 @@ pub async fn verify_entity<E: Integrable>(
         Ok(false) => Err(Error::MacMismatch {
             entity_kind: E::KIND,
         }),
-        Err(SendError::HandlerError(keyholder::Error::NotBootstrapped)) => {
-            Ok(AttestationStatus::Unavailable)
-        }
-        Err(_) => Err(Error::KeyholderSend),
+        Err(SendError::HandlerError(vault::Error::Sealed)) => Ok(AttestationStatus::Unavailable),
+        Err(_) => Err(Error::VaultSend),
     }
 }
 
+pub async fn is_signing_available(vault: &ActorRef<Vault>) -> Result<bool, Error> {
+    let state = vault.ask(GetState).await.map_err(|_| Error::VaultSend)?;
+    Ok(matches!(state, vault::VaultState::Unsealed))
+}
+
 #[cfg(test)]
 mod tests {
     use diesel::{ExpressionMethods as _, QueryDsl};
@@ -203,7 +206,10 @@ mod tests {
     use kameo::{actor::ActorRef, prelude::Spawn};
 
     use crate::{
-        actors::keyholder::{Bootstrap, KeyHolder},
+        actors::{
+            GlobalActors,
+            vault::{Bootstrap, Vault},
+        },
         db::{self, schema},
     };
     use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
@@ -218,8 +224,12 @@ 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()),
@@ -232,7 +242,7 @@ 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";
@@ -242,7 +252,7 @@ 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();
 
@@ -255,7 +265,7 @@ 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();
     }
@@ -263,7 +273,7 @@ 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";
@@ -273,7 +283,7 @@ 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();
 
@@ -285,7 +295,7 @@ 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 { .. }));
@@ -294,7 +304,7 @@ 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";
@@ -304,7 +314,7 @@ 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();
 
@@ -313,7 +323,7 @@ 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

@@ -1,12 +1,11 @@
 use arbiter_crypto::authn;
+use arbiter_macros::Hashable;
 use arbiter_proto::{ClientMetadata, transport::Bi};
 use kameo::actor::Spawn;
 use tracing::{error, info};
 
 use crate::{
-    actors::{GlobalActors, client::session::ClientSession},
-    crypto::integrity::Integrable,
-    db,
+    actors::GlobalActors, crypto::integrity::Integrable, db, peers::client::session::ClientSession,
 };
 
 #[derive(Debug, Clone)]
@@ -15,10 +14,9 @@ pub struct ClientProfile {
     pub metadata: ClientMetadata,
 }
 
-#[derive(arbiter_macros::Hashable)]
+#[derive(Hashable)]
 pub struct ClientCredentials {
     pub pubkey: authn::PublicKey,
-    pub nonce: i32,
 }
 
 impl Integrable for ClientCredentials {

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 +1,185 @@
+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_macros::Hashable;
+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;
+
+pub mod auth;
+pub mod session;
+pub mod vault_gate;
+
+#[derive(Debug, Clone, Hashable)]
+pub struct Credentials {
+    pub id: i32,
+    pub pubkey: authn::PublicKey,
+}
+
+impl Integrable for Credentials {
+    const KIND: &'static str = "useragent_credentials";
+}
+
+// Messages, sent by user agent to connection client without having a request
+#[derive(Debug)]
+pub enum OutOfBand {
+    ClientConnectionRequest { profile: ClientProfile },
+    ClientConnectionCancel { pubkey: authn::PublicKey },
+}
+
+#[derive(Clone)]
+pub struct UserAgentConnection {
+    pub(crate) db: 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 +1,294 @@
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use chacha20poly1305::{AeadInPlace, KeyInit as _, XChaCha20Poly1305, XNonce};
+use kameo::{Actor, error::SendError, messages, prelude::Message};
+use kameo_actors::message_bus::Register;
+use tokio::sync::oneshot;
+use tracing::{error, info};
+use x25519_dalek::{EphemeralSecret, PublicKey, SharedSecret};
+
+pub mod state;
+use state::*;
+
+use super::Credentials;
+use crate::{
+    actors::{
+        GlobalActors,
+        vault::{self, Bootstrap, GetState, TryUnseal, VaultState, events},
+    },
+    crypto::integrity::{self},
+    db::DatabasePool,
+};
+
+#[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,
+    },
+}