WIP: kameo::messages wiring for transport generalization

Reviewed-on: #80

AGENTS.md

@@ -66,7 +66,7 @@ cargo insta review
 The server is actor-based using the **kameo** crate. All long-lived state lives in `GlobalActors`:
 
 - **`Bootstrapper`** — Manages the one-time bootstrap token written to `~/.arbiter/bootstrap_token` on first run.
-- **`KeyHolder`** — Holds the encrypted root key and manages the Sealed/Unsealed vault state machine. On unseal, decrypts the root key into a `memsafe` hardened memory cell.
+- **`Vault`** — Holds the encrypted root key and manages the Sealed/Unsealed vault state machine. On unseal, decrypts the root key into a `memsafe` hardened memory cell.
 - **`FlowCoordinator`** — Coordinates cross-connection flow between user agents and SDK clients.
 - **`EvmActor`** — Handles EVM transaction policy enforcement and signing.
 

ARCHITECTURE.md

@@ -11,6 +11,7 @@ Arbiter distinguishes two kinds of peers:
 
 - **User Agent** — A client application used by the owner to manage the vault (create wallets, approve SDK clients, configure policies).
 - **SDK Client** — A consumer of signing capabilities, typically an automation tool. In the future, this could include a browser-based wallet.
+- **Recovery Operator** — A dormant recovery participant with narrowly scoped authority used only for custody recovery and operator replacement.
 
 ---
 
@@ -42,7 +43,149 @@ There is no bootstrap mechanism for SDK clients. They must be explicitly approve
 
 ---
 
-## 3. Server Identity
+## 3. Multi-Operator Governance
+
+When more than one User Agent is registered, the vault is treated as having multiple operators. In that mode, sensitive actions are governed by voting rather than by a single operator decision.
+
+### 3.1 Voting Rules
+
+Voting is based on the total number of registered operators:
+
+- **1 operator:** no vote is needed; the single operator decides directly.
+- **2 operators:** full consensus is required; both operators must approve.
+- **3 or more operators:** quorum is `floor(N / 2) + 1`.
+
+For a decision to count, the operator's approval or rejection must be signed by that operator's associated key. Unsigned votes, or votes that fail signature verification, are ignored.
+
+Examples:
+
+- **3 operators:** 2 approvals required
+- **4 operators:** 3 approvals required
+
+### 3.2 Actions Requiring a Vote
+
+In multi-operator mode, a successful vote is required for:
+
+- approving new SDK clients
+- granting an SDK client visibility to a wallet
+- approving a one-off transaction
+- approving creation of a persistent grant
+- approving operator replacement
+- approving server updates
+- updating Shamir secret-sharing parameters
+
+### 3.3 Special Rule for Key Rotation
+
+Key rotation always requires full quorum, regardless of the normal voting threshold.
+
+This is stricter than ordinary governance actions because rotating the root key requires every operator to participate in coordinated share refresh/update steps. The root key itself is not redistributed directly, but each operator's share material must be changed consistently.
+
+### 3.4 Root Key Custody
+
+When the vault has multiple operators, the vault root key is protected using Shamir secret sharing.
+
+The vault root key is encrypted in a way that requires reconstruction from user-held shares rather than from a single shared password.
+
+For ordinary operators, the Shamir threshold matches the ordinary governance quorum. For example:
+
+- **2 operators:** `2-of-2`
+- **3 operators:** `2-of-3`
+- **4 operators:** `3-of-4`
+
+In practice, the Shamir share set also includes Recovery Operator shares. This means the effective Shamir parameters are computed over the combined share pool while keeping the same threshold. For example:
+
+- **3 ordinary operators + 2 recovery shares:** `2-of-5`
+
+This ensures that the normal custody threshold follows the ordinary operator quorum, while still allowing dormant recovery shares to exist for break-glass recovery flows.
+
+### 3.5 Recovery Operators
+
+Recovery Operators are a separate peer type from ordinary vault operators.
+
+Their role is intentionally narrow. They can only:
+
+- participate in unsealing the vault
+- vote for operator replacement
+
+Recovery Operators do not participate in routine governance such as approving SDK clients, granting wallet visibility, approving transactions, creating grants, approving server updates, or changing Shamir parameters.
+
+### 3.6 Sleeping and Waking Recovery Operators
+
+By default, Recovery Operators are **sleeping** and do not participate in any active flow.
+
+Any ordinary operator may request that Recovery Operators **wake up**.
+
+Any ordinary operator may also cancel a pending wake-up request.
+
+This creates a dispute window before recovery powers become active. The default wake-up delay is **14 days**.
+
+Recovery Operators are therefore part of the break-glass recovery path rather than the normal operating quorum.
+
+The high-level recovery flow is:
+
+```mermaid
+sequenceDiagram
+    autonumber
+    actor Op as Ordinary Operator
+    participant Server
+    actor Other as Other Operator
+    actor Rec as Recovery Operator
+
+    Op->>Server: Request recovery wake-up
+    Server-->>Op: Wake-up pending
+    Note over Server: Default dispute window: 14 days
+
+    alt Wake-up cancelled during dispute window
+        Other->>Server: Cancel wake-up
+        Server-->>Op: Recovery cancelled
+        Server-->>Rec: Stay sleeping
+    else No cancellation for 14 days
+        Server-->>Rec: Wake up
+        Rec->>Server: Join recovery flow
+        critical Recovery authority
+            Rec->>Server: Participate in unseal
+            Rec->>Server: Vote on operator replacement
+        end
+        Server-->>Op: Recovery mode active
+    end
+```
+
+### 3.7 Committee Formation
+
+There are two ways to form a multi-operator committee:
+
+- convert an existing single-operator vault by adding new operators
+- bootstrap an unbootstrapped vault directly into multi-operator mode
+
+In both cases, committee formation is a coordinated process. Arbiter does not allow multi-operator custody to emerge implicitly from unrelated registrations.
+
+### 3.8 Bootstrapping an Unbootstrapped Vault into Multi-Operator Mode
+
+When an unbootstrapped vault is initialized as a multi-operator vault, the setup proceeds as follows:
+
+1. An operator connects to the unbootstrapped vault using a User Agent and the bootstrap token.
+2. During bootstrap setup, that operator declares:
+   - the total number of ordinary operators
+   - the total number of Recovery Operators
+3. The vault enters **multi-bootstrap mode**.
+4. While in multi-bootstrap mode:
+   - every ordinary operator must connect with a User Agent using the bootstrap token
+   - every Recovery Operator must also connect using the bootstrap token
+   - each participant is registered individually
+   - each participant's share is created and protected with that participant's credentials
+5. The vault is considered fully bootstrapped only after all declared operator and recovery-share registrations have completed successfully.
+
+This means the operator and recovery set is fixed at bootstrap completion time, based on the counts declared when multi-bootstrap mode was entered.
+
+### 3.9 Special Bootstrap Constraint for Two-Operator Vaults
+
+If a vault is declared with exactly **2 ordinary operators**, Arbiter requires at least **1 Recovery Operator** to be configured during bootstrap.
+
+This prevents the worst-case custody failure in which a `2-of-2` operator set becomes permanently unrecoverable after loss of a single operator.
+
+---
+
+## 4. Server Identity
 
 The server proves its identity using TLS with a self-signed certificate. The TLS private key is generated on first run and is long-term; no rotation mechanism exists yet due to the complexity of multi-peer coordination.
 
@@ -55,9 +198,9 @@ Peers verify the server by its **public key fingerprint**:
 
 ---
 
-## 4. Key Management
+## 5. Key Management
 
-### 4.1 Key Hierarchy
+### 5.1 Key Hierarchy
 
 There are three layers of keys:
 
@@ -72,19 +215,19 @@ This layered design enables:
 - **Password rotation** without re-encrypting every wallet key (only the root key is re-encrypted).
 - **Root key rotation** without requiring the user to change their password.
 
-### 4.2 Encryption at Rest
+### 5.2 Encryption at Rest
 
 The database stores everything in encrypted form using symmetric AEAD. The encryption scheme is versioned to support transparent migration — when the vault unseals, Arbiter automatically re-encrypts any entries that are behind the current scheme version. See [IMPLEMENTATION.md](IMPLEMENTATION.md) for the specific scheme and versioning mechanism.
 
 ---
 
-## 5. Vault Lifecycle
+## 6. Vault Lifecycle
 
-### 5.1 Sealed State
+### 6.1 Sealed State
 
 On boot, the root key is encrypted and the server cannot perform any signing operations. This state is called **Sealed**.
 
-### 5.2 Unseal Flow
+### 6.2 Unseal Flow
 
 To transition to the **Unsealed** state, a User Agent must provide the password:
 
@@ -95,7 +238,7 @@ To transition to the **Unsealed** state, a User Agent must provide the password:
    - **Success:** The root key is decrypted and placed into a hardened memory cell. The server transitions to `Unsealed`. Any entries pending encryption scheme migration are re-encrypted.
    - **Failure:** The server returns an error indicating the password is incorrect.
 
-### 5.3 Memory Protection
+### 6.3 Memory Protection
 
 Once unsealed, the root key must be protected in memory against:
 
@@ -107,9 +250,9 @@ See [IMPLEMENTATION.md](IMPLEMENTATION.md) for the current and planned memory pr
 
 ---
 
-## 6. Permission Engine
+## 7. Permission Engine
 
-### 6.1 Fundamental Rules
+### 7.1 Fundamental Rules
 
 - SDK clients have **no access by default**.
 - Access is granted **explicitly** by a User Agent.
@@ -119,11 +262,45 @@ Each blockchain requires its own policy system due to differences in static tran
 
 Arbiter is also responsible for ensuring that **transaction nonces are never reused**.
 
-### 6.2 EVM Policies
+### 7.2 EVM Policies
 
 Every EVM grant is scoped to a specific **wallet** and **chain ID**.
 
-#### 6.2.1 Transaction Sub-Grants
+#### 7.2.0 Transaction Signing Sequence
+
+The high-level interaction order is:
+
+```mermaid
+sequenceDiagram
+    autonumber
+    actor SDK as SDK Client
+    participant Server
+    participant UA as User Agent
+
+    SDK->>Server: SignTransactionRequest
+    Server->>Server: Resolve wallet and wallet visibility
+    alt Visibility approval required
+        Server->>UA: Ask for wallet visibility approval
+        UA-->>Server: Vote result
+    end
+    Server->>Server: Evaluate transaction
+    Server->>Server: Load grant and limits context
+    alt Grant approval required
+        Server->>UA: Ask for execution / grant approval
+        UA-->>Server: Vote result
+        opt Create persistent grant
+            Server->>Server: Create and store grant
+        end
+        Server->>Server: Retry evaluation
+    end
+    critical Final authorization path
+        Server->>Server: Check limits and record execution
+        Server-->>Server: Signature or evaluation error
+    end
+    Server-->>SDK: Signature or error
+```
+
+#### 7.2.1 Transaction Sub-Grants
 
 Arbiter maintains an ever-expanding database of known contracts and their ABIs. Based on contract knowledge, transaction requests fall into three categories:
 
@@ -147,7 +324,7 @@ Available restrictions:
 
 These transactions have no `calldata` and therefore cannot interact with contracts. They can be subject to the same volume and rate restrictions as above.
 
-#### 6.2.2 Global Limits
+#### 7.2.2 Global Limits
 
 In addition to sub-grant-specific restrictions, the following limits can be applied across all grant types:
 

CLAUDE.md

@@ -66,7 +66,7 @@ cargo insta review
 The server is actor-based using the **kameo** crate. All long-lived state lives in `GlobalActors`:
 
 - **`Bootstrapper`** — Manages the one-time bootstrap token written to `~/.arbiter/bootstrap_token` on first run.
-- **`KeyHolder`** — Holds the encrypted root key and manages the Sealed/Unsealed vault state machine. On unseal, decrypts the root key into a `memsafe` hardened memory cell.
+- **`Vault`** — Holds the encrypted root key and manages the Sealed/Unsealed vault state machine. On unseal, decrypts the root key into a `memsafe` hardened memory cell.
 - **`FlowCoordinator`** — Coordinates cross-connection flow between user agents and SDK clients.
 - **`EvmActor`** — Handles EVM transaction policy enforcement and signing.
 

IMPLEMENTATION.md

@@ -67,18 +67,14 @@ The `program_client.nonce` column stores the **next usable nonce** — i.e. it i
 ## Cryptography
 
 ### Authentication
-- **Client protocol:** ed25519
+- **Client protocol:** ML-DSA
 
 ### User-Agent Authentication
 
 User-agent authentication supports multiple signature schemes because platform-provided "hardware-bound" keys do not expose a uniform algorithm across operating systems and hardware.
 
-- **Supported schemes:** RSA, Ed25519, ECDSA (secp256k1)
-- **Why:** the user agent authenticates with keys backed by platform facilities, and those facilities differ by platform
-- **Apple Silicon Secure Enclave / Secure Element:** ECDSA-only in practice
-- **Windows Hello / TPM 2.0:** currently RSA-backed in our integration
-
-This is why the user-agent auth protocol carries an explicit `KeyType`, while the SDK client protocol remains fixed to ed25519.
+- **Supported schemes:** ML-DSA
+- **Why:** Secure Enclave (MacOS) support them natively, on other platforms we could emulate while they roll-out
 
 ### Encryption at Rest
 - **Scheme:** Symmetric AEAD — currently **XChaCha20-Poly1305**
@@ -128,6 +124,52 @@ The central abstraction is the `Policy` trait. Each implementation handles one s
 4. **Evaluate** — `Policy::evaluate` checks the decoded meaning against the grant's policy-specific constraints and returns any violations.
 5. **Record** — If `RunKind::Execution` and there are no violations, the engine writes to `evm_transaction_log` and calls `Policy::record_transaction` for any policy-specific logging (e.g., token transfer volume).
 
+The detailed branch structure is shown below:
+
+```mermaid
+flowchart TD
+    A[SDK Client sends sign transaction request] --> B[Server resolves wallet]
+    B --> C{Wallet exists?}
+
+    C -- No --> Z1[Return wallet not found error]
+    C -- Yes --> D[Check SDK client wallet visibility]
+
+    D --> E{Wallet visible to SDK client?}
+    E -- No --> F[Start wallet visibility voting flow]
+    F --> G{Vote approved?}
+    G -- No --> Z2[Return wallet access denied error]
+    G -- Yes --> H[Persist wallet visibility]
+    E -- Yes --> I[Classify transaction meaning]
+    H --> I
+
+    I --> J{Meaning supported?}
+    J -- No --> Z3[Return unsupported transaction error]
+    J -- Yes --> K[Find matching grant]
+
+    K --> L{Grant exists?}
+    L -- Yes --> M[Check grant limits]
+    L -- No --> N[Start execution or grant voting flow]
+
+    N --> O{User-agent decision}
+    O -- Reject --> Z4[Return no matching grant error]
+    O -- Allow once --> M
+    O -- Create grant --> P[Create grant with user-selected limits]
+    P --> Q[Persist grant]
+    Q --> M
+
+    M --> R{Limits exceeded?}
+    R -- Yes --> Z5[Return evaluation error]
+    R -- No --> S[Record transaction in logs]
+    S --> T[Produce signature]
+    T --> U[Return signature to SDK client]
+
+    note1[Limit checks include volume, count, and gas constraints.]
+    note2[Grant lookup depends on classified meaning, such as ether transfer or token transfer.]
+
+    K -. uses .-> note2
+    M -. checks .-> note1
+```
+
 ### Policy Trait
 
 | Method | Purpose |

mise.lock

@@ -48,6 +48,10 @@ backend = "cargo:cargo-features-manager"
 version = "1.46.3"
 backend = "cargo:cargo-insta"
 
+[[tools."cargo:cargo-mutants"]]
+version = "27.0.0"
+backend = "cargo:cargo-mutants"
+
 [[tools."cargo:cargo-nextest"]]
 version = "0.9.126"
 backend = "cargo:cargo-nextest"
@@ -68,6 +72,10 @@ backend = "cargo:diesel_cli"
 default-features = "false"
 features = "sqlite,sqlite-bundled"
 
+[[tools."cargo:flutter_rust_bridge_codegen"]]
+version = "2.12.0"
+backend = "cargo:flutter_rust_bridge_codegen"
+
 [[tools.flutter]]
 version = "3.38.9-stable"
 backend = "asdf:flutter"
@@ -111,30 +119,37 @@ backend = "core:python"
 [tools.python."platforms.linux-arm64"]
 checksum = "sha256:53700338695e402a1a1fe22be4a41fbdacc70e22bb308a48eca8ed67cb7992be"
 url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-aarch64-unknown-linux-gnu-install_only_stripped.tar.gz"
+provenance = "github-attestations"
 
 [tools.python."platforms.linux-arm64-musl"]
 checksum = "sha256:53700338695e402a1a1fe22be4a41fbdacc70e22bb308a48eca8ed67cb7992be"
 url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-aarch64-unknown-linux-gnu-install_only_stripped.tar.gz"
+provenance = "github-attestations"
 
 [tools.python."platforms.linux-x64"]
 checksum = "sha256:d7a9f970914bb4c88756fe3bdcc186d4feb90e9500e54f1db47dae4dc9687e39"
 url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-x86_64-unknown-linux-gnu-install_only_stripped.tar.gz"
+provenance = "github-attestations"
 
 [tools.python."platforms.linux-x64-musl"]
 checksum = "sha256:d7a9f970914bb4c88756fe3bdcc186d4feb90e9500e54f1db47dae4dc9687e39"
 url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-x86_64-unknown-linux-gnu-install_only_stripped.tar.gz"
+provenance = "github-attestations"
 
 [tools.python."platforms.macos-arm64"]
 checksum = "sha256:c43aecde4a663aebff99b9b83da0efec506479f1c3f98331442f33d2c43501f9"
 url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-aarch64-apple-darwin-install_only_stripped.tar.gz"
+provenance = "github-attestations"
 
 [tools.python."platforms.macos-x64"]
 checksum = "sha256:9ab41dbc2f100a2a45d1833b9c11165f51051c558b5213eda9a9731d5948a0c0"
 url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-x86_64-apple-darwin-install_only_stripped.tar.gz"
+provenance = "github-attestations"
 
 [tools.python."platforms.windows-x64"]
 checksum = "sha256:bbe19034b35b0267176a7442575ae7dc6343480fd4d35598cb7700173d431e09"
 url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-x86_64-pc-windows-msvc-install_only_stripped.tar.gz"
+provenance = "github-attestations"
 
 [[tools.rust]]
 version = "1.93.0"

mise.toml

@@ -12,6 +12,8 @@ protoc = "29.6"
 python = "3.14.3"
 ast-grep = "0.42.0"
 "cargo:cargo-edit" = "0.13.9"
+"cargo:cargo-mutants" = "27.0.0"
+"cargo:flutter_rust_bridge_codegen" = "2.12.0"
 
 [tasks.codegen]
 sources = ['protobufs/*.proto', 'protobufs/**/*.proto']

protobufs/shared/evm.proto

@@ -36,6 +36,10 @@ message GasLimitExceededViolation {
 }
 
 message EvalViolation {
+  message ChainIdMismatch {
+    uint64 expected = 1;
+    uint64 actual = 2;
+  }
   oneof kind {
     bytes invalid_target = 1; // 20-byte Ethereum address
     GasLimitExceededViolation gas_limit_exceeded = 2;
@@ -43,6 +47,8 @@ message EvalViolation {
     google.protobuf.Empty volumetric_limit_exceeded = 4;
     google.protobuf.Empty invalid_time = 5;
     google.protobuf.Empty invalid_transaction_type = 6;
+
+    ChainIdMismatch chain_id_mismatch = 7;
   }
 }
 

protobufs/user_agent/auth.proto

@@ -2,17 +2,9 @@ syntax = "proto3";
 
 package arbiter.user_agent.auth;
 
-enum KeyType {
-  KEY_TYPE_UNSPECIFIED = 0;
-  KEY_TYPE_ED25519 = 1;
-  KEY_TYPE_ECDSA_SECP256K1 = 2;
-  KEY_TYPE_RSA = 3;
-}
-
 message AuthChallengeRequest {
   bytes pubkey = 1;
   optional string bootstrap_token = 2;
-  KeyType key_type = 3;
 }
 
 message AuthChallenge {

server/.cargo/mutants.toml

@@ -0,0 +1 @@
+test_tool = "nextest"

server/.gitignore

@@ -0,0 +1,2 @@
+mutants.out/
+mutants.out.old/

server/Cargo.toml

@@ -20,13 +20,12 @@ tokio = { version = "1.50.0", features = ["full"] }
 ed25519-dalek = { version = "3.0.0-pre.6", features = ["rand_core"] }
 chrono = { version = "0.4.44", features = ["serde"] }
 rand = "0.10.0"
-rustls = { version = "0.23.37", features = ["aws-lc-rs"] }
+rustls = { version = "0.23.37", features = ["aws-lc-rs", "logging", "prefer-post-quantum", "std"], default-features = false }
 smlang = "0.8.0"
 thiserror = "2.0.18"
 async-trait = "0.1.89"
 futures = "0.3.32"
 tokio-stream = { version = "0.1.18", features = ["full"] }
-kameo = "0.19.2"
 prost-types = { version = "0.14.3", features = ["chrono"] }
 x25519-dalek = { version = "2.0.1", features = ["getrandom"] }
 rstest = "0.26.1"
@@ -42,4 +41,11 @@ k256 = { version = "0.13.4", features = ["ecdsa", "pkcs8"] }
 rsa = { version = "0.9", features = ["sha2"] }
 sha2 = "0.10"
 spki = "0.7"
+prost = "0.14.3"
 miette = { version = "7.6.0", features = ["fancy", "serde"] }
+mutants = "0.0.4"
+ml-dsa = { version = "0.1.0-rc.8", features = ["zeroize"] }
+base64 = "0.22.1"
+kameo = {git = "https://github.com/hdbg/kameo.git", rev = "805b417"}
+kameo_actors = {git = "https://github.com/hdbg/kameo.git", rev = "805b417"}
+

server/crates/arbiter-client/Cargo.toml

@@ -13,12 +13,12 @@ evm = ["dep:alloy"]
 
 [dependencies]
 arbiter-proto.path = "../arbiter-proto"
+arbiter-crypto.path = "../arbiter-crypto"
 alloy = { workspace = true, optional = true }
 tonic.workspace = true
 tonic.features = ["tls-aws-lc"]
 tokio.workspace = true
 tokio-stream.workspace = true
-ed25519-dalek.workspace = true
 thiserror.workspace = true
 http = "1.4.0"
 rustls-webpki = { version = "0.103.10", features = ["aws-lc-rs"] }

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

@@ -1,5 +1,6 @@
+use arbiter_crypto::authn::{CLIENT_CONTEXT, SigningKey, format_challenge};
 use arbiter_proto::{
-    ClientMetadata, format_challenge,
+    ClientMetadata,
     proto::{
         client::{
             ClientRequest,
@@ -14,7 +15,6 @@ use arbiter_proto::{
         shared::ClientInfo as ProtoClientInfo,
     },
 };
-use ed25519_dalek::Signer as _;
 
 use crate::{
     storage::StorageError,
@@ -54,14 +54,14 @@ fn map_auth_result(code: i32) -> AuthError {
 async fn send_auth_challenge_request(
     transport: &mut ClientTransport,
     metadata: ClientMetadata,
-    key: &ed25519_dalek::SigningKey,
+    key: &SigningKey,
 ) -> std::result::Result<(), AuthError> {
     transport
         .send(ClientRequest {
             request_id: next_request_id(),
             payload: Some(ClientRequestPayload::Auth(proto_auth::Request {
                 payload: Some(AuthRequestPayload::ChallengeRequest(AuthChallengeRequest {
-                    pubkey: key.verifying_key().to_bytes().to_vec(),
+                    pubkey: key.public_key().to_bytes(),
                     client_info: Some(ProtoClientInfo {
                         name: metadata.name,
                         description: metadata.description,
@@ -95,11 +95,14 @@ async fn receive_auth_challenge(
 
 async fn send_auth_challenge_solution(
     transport: &mut ClientTransport,
-    key: &ed25519_dalek::SigningKey,
+    key: &SigningKey,
     challenge: AuthChallenge,
 ) -> std::result::Result<(), AuthError> {
     let challenge_payload = format_challenge(challenge.nonce, &challenge.pubkey);
-    let signature = key.sign(&challenge_payload).to_bytes().to_vec();
+    let signature = key
+        .sign_message(&challenge_payload, CLIENT_CONTEXT)
+        .map_err(|_| AuthError::UnexpectedAuthResponse)?
+        .to_bytes();
 
     transport
         .send(ClientRequest {
@@ -140,7 +143,7 @@ async fn receive_auth_confirmation(
 pub(crate) async fn authenticate(
     transport: &mut ClientTransport,
     metadata: ClientMetadata,
-    key: &ed25519_dalek::SigningKey,
+    key: &SigningKey,
 ) -> std::result::Result<(), AuthError> {
     send_auth_challenge_request(transport, metadata, key).await?;
     let challenge = receive_auth_challenge(transport).await?;

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

@@ -1,3 +1,4 @@
+use arbiter_crypto::authn::SigningKey;
 use arbiter_proto::{
     ClientMetadata, proto::arbiter_service_client::ArbiterServiceClient, url::ArbiterUrl,
 };
@@ -60,7 +61,7 @@ impl ArbiterClient {
     pub async fn connect_with_key(
         url: ArbiterUrl,
         metadata: ClientMetadata,
-        key: ed25519_dalek::SigningKey,
+        key: SigningKey,
     ) -> Result<Self, Error> {
         let anchor = webpki::anchor_from_trusted_cert(&url.ca_cert)?.to_owned();
         let tls = ClientTlsConfig::new().trust_anchor(anchor);

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

@@ -1,3 +1,4 @@
+use arbiter_crypto::authn::SigningKey;
 use arbiter_proto::home_path;
 use std::path::{Path, PathBuf};
 
@@ -11,7 +12,7 @@ pub enum StorageError {
 }
 
 pub trait SigningKeyStorage {
-    fn load_or_create(&self) -> std::result::Result<ed25519_dalek::SigningKey, StorageError>;
+    fn load_or_create(&self) -> std::result::Result<SigningKey, StorageError>;
 }
 
 #[derive(Debug, Clone)]
@@ -20,7 +21,7 @@ pub struct FileSigningKeyStorage {
 }
 
 impl FileSigningKeyStorage {
-    pub const DEFAULT_FILE_NAME: &str = "sdk_client_ed25519.key";
+    pub const DEFAULT_FILE_NAME: &str = "sdk_client_ml_dsa.key";
 
     pub fn new(path: impl Into<PathBuf>) -> Self {
         Self { path: path.into() }
@@ -30,7 +31,7 @@ impl FileSigningKeyStorage {
         Ok(Self::new(home_path()?.join(Self::DEFAULT_FILE_NAME)))
     }
 
-    fn read_key(path: &Path) -> std::result::Result<ed25519_dalek::SigningKey, StorageError> {
+    fn read_key(path: &Path) -> std::result::Result<SigningKey, StorageError> {
         let bytes = std::fs::read(path)?;
         let raw: [u8; 32] =
             bytes
@@ -39,12 +40,12 @@ impl FileSigningKeyStorage {
                     expected: 32,
                     actual: v.len(),
                 })?;
-        Ok(ed25519_dalek::SigningKey::from_bytes(&raw))
+        Ok(SigningKey::from_seed(raw))
     }
 }
 
 impl SigningKeyStorage for FileSigningKeyStorage {
-    fn load_or_create(&self) -> std::result::Result<ed25519_dalek::SigningKey, StorageError> {
+    fn load_or_create(&self) -> std::result::Result<SigningKey, StorageError> {
         if let Some(parent) = self.path.parent() {
             std::fs::create_dir_all(parent)?;
         }
@@ -53,8 +54,8 @@ impl SigningKeyStorage for FileSigningKeyStorage {
             return Self::read_key(&self.path);
         }
 
-        let key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-        let raw_key = key.to_bytes();
+        let key = SigningKey::generate();
+        let raw_key = key.to_seed();
 
         // Use create_new to prevent accidental overwrite if another process creates the key first.
         match std::fs::OpenOptions::new()
@@ -103,7 +104,7 @@ mod tests {
             .load_or_create()
             .expect("second load_or_create should read same key");
 
-        assert_eq!(key_a.to_bytes(), key_b.to_bytes());
+        assert_eq!(key_a.to_seed(), key_b.to_seed());
         assert!(path.exists());
 
         std::fs::remove_file(path).expect("temp key file should be removable");

server/crates/arbiter-crypto/.gitignore

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

server/crates/arbiter-crypto/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "arbiter-crypto"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+ml-dsa = {workspace = true, optional = true }
+rand = {workspace = true, optional = true}
+base64 = {workspace = true, optional = true }
+memsafe = {version = "0.4.0", optional = true}
+x-wing = { version = "0.1.0-rc.0", features = ["zeroize"] }
+
+[lints]
+workspace = true
+
+[features]
+default = ["authn", "safecell"]
+authn = ["dep:ml-dsa", "dep:rand", "dep:base64"]
+safecell = ["dep:memsafe"]

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

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

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

@@ -0,0 +1,194 @@
+use std::hash::Hash;
+
+use base64::{Engine as _, prelude::BASE64_STANDARD};
+use ml_dsa::{
+    EncodedVerifyingKey, Error, KeyGen, MlDsa87, Seed, Signature as MlDsaSignature,
+    SigningKey as MlDsaSigningKey, VerifyingKey as MlDsaVerifyingKey, signature::Keypair as _,
+};
+
+pub static CLIENT_CONTEXT: &[u8] = b"arbiter_client";
+pub static USERAGENT_CONTEXT: &[u8] = b"arbiter_user_agent";
+
+pub fn format_challenge(nonce: i32, pubkey: &[u8]) -> Vec<u8> {
+    let concat_form = format!("{}:{}", nonce, BASE64_STANDARD.encode(pubkey));
+    concat_form.into_bytes()
+}
+
+pub type KeyParams = MlDsa87;
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct PublicKey(Box<MlDsaVerifyingKey<KeyParams>>);
+
+impl Hash for PublicKey {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        self.to_bytes().hash(state);
+    }
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct Signature(Box<MlDsaSignature<KeyParams>>);
+
+#[derive(Debug)]
+pub struct SigningKey(Box<MlDsaSigningKey<KeyParams>>);
+
+impl PublicKey {
+    pub fn to_bytes(&self) -> Vec<u8> {
+        self.0.encode().to_vec()
+    }
+
+    pub fn verify(&self, nonce: i32, context: &[u8], signature: &Signature) -> bool {
+        self.0.verify_with_context(
+            &format_challenge(nonce, &self.to_bytes()),
+            context,
+            &signature.0,
+        )
+    }
+}
+
+impl Signature {
+    pub fn to_bytes(&self) -> Vec<u8> {
+        self.0.encode().to_vec()
+    }
+}
+
+impl SigningKey {
+    pub fn generate() -> Self {
+        Self(Box::new(KeyParams::key_gen(&mut rand::rng())))
+    }
+
+    pub fn from_seed(seed: [u8; 32]) -> Self {
+        Self(Box::new(KeyParams::from_seed(&Seed::from(seed))))
+    }
+
+    pub fn to_seed(&self) -> [u8; 32] {
+        self.0.to_seed().into()
+    }
+
+    pub fn public_key(&self) -> PublicKey {
+        self.0.verifying_key().into()
+    }
+
+    pub fn sign_message(&self, message: &[u8], context: &[u8]) -> Result<Signature, Error> {
+        self.0
+            .signing_key()
+            .sign_deterministic(message, context)
+            .map(Into::into)
+    }
+
+    pub fn sign_challenge(&self, nonce: i32, context: &[u8]) -> Result<Signature, Error> {
+        self.sign_message(
+            &format_challenge(nonce, &self.public_key().to_bytes()),
+            context,
+        )
+    }
+}
+
+impl From<MlDsaVerifyingKey<KeyParams>> for PublicKey {
+    fn from(value: MlDsaVerifyingKey<KeyParams>) -> Self {
+        Self(Box::new(value))
+    }
+}
+
+impl From<MlDsaSignature<KeyParams>> for Signature {
+    fn from(value: MlDsaSignature<KeyParams>) -> Self {
+        Self(Box::new(value))
+    }
+}
+
+impl From<MlDsaSigningKey<KeyParams>> for SigningKey {
+    fn from(value: MlDsaSigningKey<KeyParams>) -> Self {
+        Self(Box::new(value))
+    }
+}
+
+impl TryFrom<Vec<u8>> for PublicKey {
+    type Error = ();
+
+    fn try_from(value: Vec<u8>) -> Result<Self, Self::Error> {
+        Self::try_from(value.as_slice())
+    }
+}
+
+impl TryFrom<&'_ [u8]> for PublicKey {
+    type Error = ();
+
+    fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
+        let encoded = EncodedVerifyingKey::<KeyParams>::try_from(value).map_err(|_| ())?;
+        Ok(Self(Box::new(MlDsaVerifyingKey::decode(&encoded))))
+    }
+}
+
+impl TryFrom<Vec<u8>> for Signature {
+    type Error = ();
+
+    fn try_from(value: Vec<u8>) -> Result<Self, Self::Error> {
+        Self::try_from(value.as_slice())
+    }
+}
+
+impl TryFrom<&'_ [u8]> for Signature {
+    type Error = ();
+
+    fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
+        MlDsaSignature::try_from(value)
+            .map(|sig| Self(Box::new(sig)))
+            .map_err(|_| ())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use ml_dsa::{KeyGen, MlDsa87, signature::Keypair as _};
+
+    use super::{CLIENT_CONTEXT, PublicKey, Signature, SigningKey, USERAGENT_CONTEXT};
+
+    #[test]
+    fn public_key_round_trip_decodes() {
+        let key = MlDsa87::key_gen(&mut rand::rng());
+        let encoded = PublicKey::from(key.verifying_key()).to_bytes();
+
+        let decoded = PublicKey::try_from(encoded.as_slice()).expect("public key should decode");
+
+        assert_eq!(decoded, PublicKey::from(key.verifying_key()));
+    }
+
+    #[test]
+    fn signature_round_trip_decodes() {
+        let key = SigningKey::generate();
+        let signature = key
+            .sign_message(b"challenge", CLIENT_CONTEXT)
+            .expect("signature should be created");
+
+        let decoded =
+            Signature::try_from(signature.to_bytes().as_slice()).expect("signature should decode");
+
+        assert_eq!(decoded, signature);
+    }
+
+    #[test]
+    fn challenge_verification_uses_context_and_canonical_key_bytes() {
+        let key = SigningKey::generate();
+        let public_key = key.public_key();
+        let nonce = 17;
+        let signature = key
+            .sign_challenge(nonce, CLIENT_CONTEXT)
+            .expect("signature should be created");
+
+        assert!(public_key.verify(nonce, CLIENT_CONTEXT, &signature));
+        assert!(!public_key.verify(nonce, USERAGENT_CONTEXT, &signature));
+    }
+
+    #[test]
+    fn signing_key_round_trip_seed_preserves_public_key_and_signing() {
+        let original = SigningKey::generate();
+        let restored = SigningKey::from_seed(original.to_seed());
+
+        assert_eq!(restored.public_key(), original.public_key());
+
+        let signature = restored
+            .sign_challenge(9, CLIENT_CONTEXT)
+            .expect("signature should be created");
+
+        assert!(restored.public_key().verify(9, CLIENT_CONTEXT, &signature));
+    }
+}

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

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

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

@@ -105,6 +105,11 @@ impl<T> SafeCellHandle<T> for MemSafeCell<T> {
 
 fn abort_memory_breach(action: &str, err: &memsafe::error::MemoryError) -> ! {
     eprintln!("fatal {action}: {err}");
+    // SAFETY: Intentionally cause a segmentation fault to prevent further execution in a compromised state.
+    unsafe {
+        let unsafe_pointer = std::ptr::null_mut::<u8>();
+        std::ptr::write_volatile(unsafe_pointer, 0);
+    }
     std::process::abort();
 }
 

server/crates/arbiter-proto/Cargo.toml

@@ -11,13 +11,13 @@ tokio.workspace = true
 futures.workspace = true
 hex = "0.4.3"
 tonic-prost = "0.14.5"
-prost = "0.14.3"
+prost.workspace = true
 kameo.workspace = true
 url = "2.5.8"
 miette.workspace = true
 thiserror.workspace = true
 rustls-pki-types.workspace = true
-base64 = "0.22.1"
+base64.workspace = true
 prost-types.workspace = true
 tracing.workspace = true
 async-trait.workspace = true

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

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

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

@@ -106,6 +106,36 @@ pub trait Receiver<Inbound>: Send + Sync {
 /// any built-in correlation mechanism between inbound and outbound items.
 pub trait Bi<Inbound, Outbound>: Sender<Outbound> + Receiver<Inbound> + Send + Sync {}
 
+#[async_trait]
+impl<T, Outbound> Sender<Outbound> for &mut T
+where
+    T: Sender<Outbound> + ?Sized,
+    Outbound: Send + 'static,
+{
+    async fn send(&mut self, item: Outbound) -> Result<(), Error> {
+        (**self).send(item).await
+    }
+}
+
+#[async_trait]
+impl<T, Inbound> Receiver<Inbound> for &mut T
+where
+    T: Receiver<Inbound> + ?Sized,
+    Inbound: Send + 'static,
+{
+    async fn recv(&mut self) -> Option<Inbound> {
+        (**self).recv().await
+    }
+}
+
+impl<T, Inbound, Outbound> Bi<Inbound, Outbound> for &mut T
+where
+    T: Bi<Inbound, Outbound> + ?Sized,
+    Inbound: Send + 'static,
+    Outbound: Send + 'static,
+{
+}
+
 pub trait SplittableBi<Inbound, Outbound>: Bi<Inbound, Outbound> {
     type Sender: Sender<Outbound>;
     type Receiver: Receiver<Inbound>;

server/crates/arbiter-server/Cargo.toml

@@ -16,8 +16,8 @@ diesel-async = { version = "0.8.0", features = [
     "sqlite",
     "tokio",
 ] }
-ed25519-dalek.workspace = true
 arbiter-proto.path = "../arbiter-proto"
+arbiter-crypto.path = "../arbiter-crypto"
 tracing.workspace = true
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 tonic.workspace = true
@@ -36,25 +36,32 @@ dashmap = "6.1.0"
 rand.workspace = true
 rcgen.workspace = true
 chrono.workspace = true
-memsafe = "0.4.0"
 zeroize = { version = "1.8.2", features = ["std", "simd"] }
 kameo.workspace = true
-x25519-dalek.workspace = true
 chacha20poly1305 = { version = "0.10.1", features = ["std"] }
 argon2 = { version = "0.5.3", features = ["zeroize"] }
 restructed = "0.2.2"
 strum = { version = "0.28.0", features = ["derive"] }
 pem = "3.0.6"
-k256.workspace = true
-rsa.workspace = true
 sha2.workspace = true
 hmac = "0.12"
 spki.workspace = true
 alloy.workspace = true
 prost-types.workspace = true
+prost.workspace = true
 arbiter-tokens-registry.path = "../arbiter-tokens-registry"
 anyhow = "1.0.102"
+serde_with = "3.18.0"
+mutants.workspace = true
+subtle = "2.6.1"
+ml-dsa.workspace = true
+ed25519-dalek.workspace = true
+x25519-dalek.workspace = true
+k256.workspace = true
+kameo_actors.workspace = true
 
 [dev-dependencies]
 insta = "1.46.3"
+proptest = "1.11.0"
+rstest.workspace = true
 test-log = { version = "0.2", default-features = false, features = ["trace"] }

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

@@ -47,8 +47,7 @@ create table if not exists useragent_client (
     id integer not null primary key,
     nonce integer not null default(1), -- used for auth challenge
     public_key blob not null,
-    pubkey_integrity_tag blob,
-    key_type integer not null default(1), -- 1=Ed25519, 2=ECDSA(secp256k1)
+    key_type integer not null default(1),
     created_at integer not null default(unixepoch ('now')),
     updated_at integer not null default(unixepoch ('now'))
 ) STRICT;
@@ -192,3 +191,19 @@ create table if not exists evm_ether_transfer_grant_target (
 ) STRICT;
 
 create unique index if not exists uniq_ether_transfer_target on evm_ether_transfer_grant_target (grant_id, address);
+
+-- ===============================
+-- Integrity Envelopes
+-- ===============================
+create table if not exists integrity_envelope (
+    id integer not null primary key,
+    entity_kind text not null,
+    entity_id blob not null,
+    payload_version integer not null,
+    key_version integer not null,
+    mac blob not null, -- 20-byte recipient address
+    signed_at integer not null default(unixepoch ('now')),
+    created_at integer not null default(unixepoch ('now'))
+) STRICT;
+
+create unique index if not exists uniq_integrity_envelope_entity on integrity_envelope (entity_kind, entity_id);

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

@@ -4,6 +4,7 @@ use diesel_async::RunQueryDsl;
 use kameo::{Actor, messages};
 
 use rand::{RngExt, distr::Alphanumeric, make_rng, rngs::StdRng};
+use subtle::ConstantTimeEq as _;
 use thiserror::Error;
 
 use crate::db::{self, DatabasePool, schema};
@@ -44,14 +45,14 @@ pub struct Bootstrapper {
 
 impl Bootstrapper {
     pub async fn new(db: &DatabasePool) -> Result<Self, Error> {
-        let mut conn = db.get().await?;
+        let row_count: i64 = {
+            let mut conn = db.get().await?;
 
-        let row_count: i64 = schema::useragent_client::table
-            .count()
-            .get_result(&mut conn)
-            .await?;
-
-        drop(conn);
+            schema::useragent_client::table
+                .count()
+                .get_result(&mut conn)
+                .await?
+        };
 
         let token = if row_count == 0 {
             let token = generate_token().await?;
@@ -69,7 +70,13 @@ impl Bootstrapper {
     #[message]
     pub fn is_correct_token(&self, token: String) -> bool {
         match &self.token {
-            Some(expected) => *expected == token,
+            Some(expected) => {
+                let expected_bytes = expected.as_bytes();
+                let token_bytes = token.as_bytes();
+
+                let choice = expected_bytes.ct_eq(token_bytes);
+                bool::from(choice)
+            }
             None => false,
         }
     }

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

@@ -7,21 +7,22 @@ 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,
-        models::{self, SqliteTimestamp},
+        models::{self},
         schema,
     },
     evm::{
-        self, RunKind,
+        self, ListError, RunKind,
         policies::{
-            FullGrant, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
+            CombinedSettings, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
             ether_transfer::EtherTransfer, token_transfers::TokenTransfer,
         },
     },
-    safe_cell::{SafeCell, SafeCellHandle as _},
 };
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 
 pub use crate::evm::safe_signer;
 
@@ -33,11 +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),
@@ -48,32 +49,35 @@ 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),
+
+    #[error("Integrity violation: {0}")]
+    Integrity(#[from] integrity::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());
+        let engine = evm::Engine::new(db.clone(), vault.clone());
         Self {
-            keyholder,
+            vault,
             db,
             rng,
             engine,
@@ -90,10 +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)
@@ -132,46 +136,59 @@ impl EvmActor {
         &mut self,
         basic: SharedGrantSettings,
         grant: SpecificGrant,
-    ) -> Result<i32, DatabaseError> {
+    ) -> Result<i32, Error> {
         match grant {
-            SpecificGrant::EtherTransfer(settings) => {
-                self.engine
-                    .create_grant::<EtherTransfer>(FullGrant {
-                        basic,
-                        specific: settings,
-                    })
-                    .await
-            }
-            SpecificGrant::TokenTransfer(settings) => {
-                self.engine
-                    .create_grant::<TokenTransfer>(FullGrant {
-                        basic,
-                        specific: settings,
-                    })
-                    .await
-            }
+            SpecificGrant::EtherTransfer(settings) => self
+                .engine
+                .create_grant::<EtherTransfer>(CombinedSettings {
+                    shared: basic,
+                    specific: settings,
+                })
+                .await
+                .map_err(Error::from),
+            SpecificGrant::TokenTransfer(settings) => self
+                .engine
+                .create_grant::<TokenTransfer>(CombinedSettings {
+                    shared: basic,
+                    specific: settings,
+                })
+                .await
+                .map_err(Error::from),
         }
     }
 
     #[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)?;
-        diesel::update(schema::evm_basic_grant::table)
-            .filter(schema::evm_basic_grant::id.eq(grant_id))
-            .set(schema::evm_basic_grant::revoked_at.eq(SqliteTimestamp::now()))
-            .execute(&mut conn)
-            .await
-            .map_err(DatabaseError::from)?;
-        Ok(())
+    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 vault = self.vault.clone();
+
+        // diesel_async::AsyncConnection::transaction(&mut conn, |conn| {
+        //     Box::pin(async move {
+        //         diesel::update(schema::evm_basic_grant::table)
+        //             .filter(schema::evm_basic_grant::id.eq(grant_id))
+        //             .set(schema::evm_basic_grant::revoked_at.eq(SqliteTimestamp::now()))
+        //             .execute(conn)
+        //             .await?;
+
+        //         let signed = integrity::evm::load_signed_grant_by_basic_id(conn, grant_id).await?;
+
+        //         diesel::result::QueryResult::Ok(())
+        //     })
+        // })
+        // .await
+        // .map_err(DatabaseError::from)?;
+
+        // Ok(())
+        todo!()
     }
 
     #[message]
     pub async fn useragent_list_grants(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
-        Ok(self
-            .engine
-            .list_all_grants()
-            .await
-            .map_err(DatabaseError::from)?)
+        match self.engine.list_all_grants().await {
+            Ok(grants) => Ok(grants),
+            Err(ListError::Database(db_err)) => Err(Error::Database(db_err)),
+            Err(ListError::Integrity(integrity_err)) => Err(Error::Integrity(integrity_err)),
+        }
     }
 
     #[message]
@@ -237,12 +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

@@ -9,10 +9,12 @@ 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,
+    peers::{
+        client::{ClientProfile, session::ClientSession},
+        user_agent::UserAgentSession,
+    },
 };
 
 pub mod client_connect_approval;

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

@@ -1,47 +1,53 @@
 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, 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 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?);
         Ok(Self {
             bootstrapper: Bootstrapper::spawn(Bootstrapper::new(&db).await?),
             evm: EvmActor::spawn(EvmActor::new(key_holder.clone(), db)),
-            key_holder,
+            vault: key_holder,
             flow_coordinator: FlowCoordinator::spawn(FlowCoordinator::default()),
+            events: message_bus,
         })
     }
 }

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

@@ -1,356 +0,0 @@
-use arbiter_proto::transport::Bi;
-use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl, update};
-use diesel_async::RunQueryDsl;
-use kameo::error::SendError;
-use tracing::error;
-
-use super::Error;
-use crate::{
-    actors::{
-        bootstrap::ConsumeToken,
-        keyholder::{self, SignIntegrityTag},
-        user_agent::{AuthPublicKey, UserAgentConnection, auth::Outbound},
-    },
-    crypto::integrity::v1::USERAGENT_INTEGRITY_TAG,
-    db::schema,
-};
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum AttestationStatus {
-    Attested,
-    NotAttested,
-    Unavailable,
-}
-
-pub struct ChallengeRequest {
-    pub pubkey: AuthPublicKey,
-}
-
-pub struct BootstrapAuthRequest {
-    pub pubkey: AuthPublicKey,
-    pub token: String,
-}
-
-pub struct ChallengeContext {
-    pub challenge_nonce: i32,
-    pub key: AuthPublicKey,
-}
-
-pub struct ChallengeSolution {
-    pub solution: Vec<u8>,
-}
-
-smlang::statemachine!(
-    name: Auth,
-    custom_error: true,
-    transitions: {
-        *Init + AuthRequest(ChallengeRequest) / async prepare_challenge = SentChallenge(ChallengeContext),
-        Init + BootstrapAuthRequest(BootstrapAuthRequest) / async verify_bootstrap_token = AuthOk(AuthPublicKey),
-        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) / async verify_solution = AuthOk(AuthPublicKey),
-    }
-);
-
-async fn create_nonce(
-    db: &crate::db::DatabasePool,
-    pubkey_bytes: &[u8],
-    key_type: crate::db::models::KeyType,
-) -> Result<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 {
-                let current_nonce = schema::useragent_client::table
-                    .filter(schema::useragent_client::public_key.eq(pubkey_bytes.to_vec()))
-                    .filter(schema::useragent_client::key_type.eq(key_type))
-                    .select(schema::useragent_client::nonce)
-                    .first::<i32>(conn)
-                    .await?;
-
-                update(schema::useragent_client::table)
-                    .filter(schema::useragent_client::public_key.eq(pubkey_bytes.to_vec()))
-                    .filter(schema::useragent_client::key_type.eq(key_type))
-                    .set(schema::useragent_client::nonce.eq(current_nonce + 1))
-                    .execute(conn)
-                    .await?;
-
-                Result::<_, diesel::result::Error>::Ok(current_nonce)
-            })
-        })
-        .await
-        .optional()
-        .map_err(|e| {
-            error!(error = ?e, "Database error");
-            Error::internal("Database operation failed")
-        })?
-        .ok_or_else(|| {
-            error!(?pubkey_bytes, "Public key not found in database");
-            Error::UnregisteredPublicKey
-        })
-}
-
-async fn register_key(
-    db: &crate::db::DatabasePool,
-    pubkey: &AuthPublicKey,
-    integrity_tag: Option<Vec<u8>>,
-) -> Result<(), Error> {
-    let pubkey_bytes = pubkey.to_stored_bytes();
-    let key_type = pubkey.key_type();
-    let mut conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::internal("Database unavailable")
-    })?;
-
-    diesel::insert_into(schema::useragent_client::table)
-        .values((
-            schema::useragent_client::public_key.eq(pubkey_bytes),
-            schema::useragent_client::nonce.eq(1),
-            schema::useragent_client::key_type.eq(key_type),
-            schema::useragent_client::pubkey_integrity_tag.eq(integrity_tag),
-        ))
-        .execute(&mut conn)
-        .await
-        .map_err(|e| {
-            error!(error = ?e, "Database error");
-            Error::internal("Database operation failed")
-        })?;
-
-    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> {
-        match self.verify_pubkey_attestation_status(&pubkey).await? {
-            AttestationStatus::Attested | AttestationStatus::Unavailable => {}
-            AttestationStatus::NotAttested => {
-                return Err(Error::InvalidChallengeSolution);
-            }
-        }
-
-        let stored_bytes = pubkey.to_stored_bytes();
-        let nonce = create_nonce(&self.conn.db, &stored_bytes, pubkey.key_type()).await?;
-
-        self.transport
-            .send(Ok(Outbound::AuthChallenge { nonce }))
-            .await
-            .map_err(|e| {
-                error!(?e, "Failed to send auth challenge");
-                Error::Transport
-            })?;
-
-        Ok(ChallengeContext {
-            challenge_nonce: nonce,
-            key: pubkey,
-        })
-    }
-
-    #[allow(missing_docs)]
-    #[allow(clippy::result_unit_err)]
-    async fn verify_bootstrap_token(
-        &mut self,
-        BootstrapAuthRequest { pubkey, token }: BootstrapAuthRequest,
-    ) -> Result<AuthPublicKey, Self::Error> {
-        let token_ok: bool = self
-            .conn
-            .actors
-            .bootstrapper
-            .ask(ConsumeToken {
-                token: token.clone(),
-            })
-            .await
-            .map_err(|e| {
-                error!(?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);
-        }
-
-        let integrity_tag = self
-            .try_sign_pubkey_integrity_tag(&pubkey)
-            .await
-            .map_err(|err| {
-                error!(?err, "Failed to sign user-agent pubkey integrity tag");
-                Error::internal("Failed to sign user-agent pubkey integrity tag")
-            })?;
-
-        register_key(&self.conn.db, &pubkey, integrity_tag).await?;
-
-        self.transport
-            .send(Ok(Outbound::AuthSuccess))
-            .await
-            .map_err(|_| Error::Transport)?;
-
-        Ok(pubkey)
-    }
-
-    #[allow(missing_docs)]
-    #[allow(clippy::unused_unit)]
-    async fn verify_solution(
-        &mut self,
-        ChallengeContext {
-            challenge_nonce,
-            key,
-        }: &ChallengeContext,
-        ChallengeSolution { solution }: ChallengeSolution,
-    ) -> Result<AuthPublicKey, Self::Error> {
-        let formatted = arbiter_proto::format_challenge(*challenge_nonce, &key.to_stored_bytes());
-
-        let valid = match key {
-            AuthPublicKey::Ed25519(vk) => {
-                let sig = solution.as_slice().try_into().map_err(|_| {
-                    error!(?solution, "Invalid Ed25519 signature length");
-                    Error::InvalidChallengeSolution
-                })?;
-                vk.verify_strict(&formatted, &sig).is_ok()
-            }
-            AuthPublicKey::EcdsaSecp256k1(vk) => {
-                use k256::ecdsa::signature::Verifier as _;
-                let sig = k256::ecdsa::Signature::try_from(solution.as_slice()).map_err(|_| {
-                    error!(?solution, "Invalid ECDSA signature bytes");
-                    Error::InvalidChallengeSolution
-                })?;
-                vk.verify(&formatted, &sig).is_ok()
-            }
-            AuthPublicKey::Rsa(pk) => {
-                use rsa::signature::Verifier as _;
-                let verifying_key = rsa::pss::VerifyingKey::<sha2::Sha256>::new(pk.clone());
-                let sig = rsa::pss::Signature::try_from(solution.as_slice()).map_err(|_| {
-                    error!(?solution, "Invalid RSA signature bytes");
-                    Error::InvalidChallengeSolution
-                })?;
-                verifying_key.verify(&formatted, &sig).is_ok()
-            }
-        };
-
-        match valid {
-            true => {
-                self.transport
-                    .send(Ok(Outbound::AuthSuccess))
-                    .await
-                    .map_err(|_| Error::Transport)?;
-                Ok(key.clone())
-            }
-            false => {
-                self.transport
-                    .send(Err(Error::InvalidChallengeSolution))
-                    .await
-                    .map_err(|_| Error::Transport)?;
-                Err(Error::InvalidChallengeSolution)
-            }
-        }
-    }
-}
-
-impl<T> AuthContext<'_, T>
-where
-    T: Bi<super::Inbound, Result<super::Outbound, Error>> + Send,
-{
-    async fn try_sign_pubkey_integrity_tag(
-        &self,
-        pubkey: &AuthPublicKey,
-    ) -> Result<Option<Vec<u8>>, Error> {
-        let signed = self
-            .conn
-            .actors
-            .key_holder
-            .ask(SignIntegrityTag {
-                purpose_tag: USERAGENT_INTEGRITY_TAG.to_vec(),
-                data_parts: vec![
-                    (pubkey.key_type() as i32).to_be_bytes().to_vec(),
-                    pubkey.to_stored_bytes(),
-                ],
-            })
-            .await;
-
-        match signed {
-            Ok(tag) => Ok(Some(tag)),
-            Err(SendError::HandlerError(keyholder::Error::NotBootstrapped)) => Ok(None),
-            Err(SendError::HandlerError(err)) => {
-                error!(
-                    ?err,
-                    "Keyholder failed to sign user-agent pubkey integrity tag"
-                );
-                Err(Error::internal(
-                    "Keyholder failed to sign user-agent pubkey integrity tag",
-                ))
-            }
-            Err(err) => {
-                error!(
-                    ?err,
-                    "Failed to contact keyholder for user-agent pubkey integrity tag"
-                );
-                Err(Error::internal(
-                    "Failed to contact keyholder for user-agent pubkey integrity tag",
-                ))
-            }
-        }
-    }
-
-    async fn verify_pubkey_attestation_status(
-        &self,
-        pubkey: &AuthPublicKey,
-    ) -> Result<AttestationStatus, Error> {
-        let stored_tag: Option<Option<Vec<u8>>> = {
-            let mut conn = self.conn.db.get().await.map_err(|e| {
-                error!(error = ?e, "Database pool error");
-                Error::internal("Database unavailable")
-            })?;
-
-            schema::useragent_client::table
-                .filter(schema::useragent_client::public_key.eq(pubkey.to_stored_bytes()))
-                .filter(schema::useragent_client::key_type.eq(pubkey.key_type()))
-                .select(schema::useragent_client::pubkey_integrity_tag)
-                .first::<Option<Vec<u8>>>(&mut conn)
-                .await
-                .optional()
-                .map_err(|e| {
-                    error!(error = ?e, "Database error");
-                    Error::internal("Database operation failed")
-                })?
-        };
-
-        let Some(stored_tag) = stored_tag else {
-            return Err(Error::UnregisteredPublicKey);
-        };
-
-        let Some(expected_tag) = self.try_sign_pubkey_integrity_tag(pubkey).await? else {
-            return Ok(AttestationStatus::Unavailable);
-        };
-
-        match stored_tag {
-            Some(stored_tag) if stored_tag == expected_tag => Ok(AttestationStatus::Attested),
-            Some(_) => {
-                error!("User-agent pubkey integrity tag mismatch");
-                Ok(AttestationStatus::NotAttested)
-            }
-            None => {
-                error!("Missing pubkey integrity tag for registered key while vault is unsealed");
-                Ok(AttestationStatus::NotAttested)
-            }
-        }
-    }
-}

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

@@ -1,94 +0,0 @@
-use crate::{
-    actors::{GlobalActors, client::ClientProfile},
-    db::{self, models::KeyType},
-};
-
-/// Abstraction over Ed25519 / ECDSA-secp256k1 / RSA public keys used during the auth handshake.
-#[derive(Clone, Debug)]
-pub enum AuthPublicKey {
-    Ed25519(ed25519_dalek::VerifyingKey),
-    /// Compressed SEC1 public key; signature bytes are raw 64-byte (r||s).
-    EcdsaSecp256k1(k256::ecdsa::VerifyingKey),
-    /// RSA-2048+ public key (Windows Hello / KeyCredentialManager); signature bytes are PSS+SHA-256.
-    Rsa(rsa::RsaPublicKey),
-}
-
-impl AuthPublicKey {
-    /// Canonical bytes stored in DB and echoed back in the challenge.
-    /// Ed25519: raw 32 bytes. ECDSA: SEC1 compressed 33 bytes. RSA: DER-encoded SPKI.
-    pub fn to_stored_bytes(&self) -> Vec<u8> {
-        match self {
-            AuthPublicKey::Ed25519(k) => k.to_bytes().to_vec(),
-            // SEC1 compressed (33 bytes) is the natural compact format for secp256k1
-            AuthPublicKey::EcdsaSecp256k1(k) => k.to_encoded_point(true).as_bytes().to_vec(),
-            AuthPublicKey::Rsa(k) => {
-                use rsa::pkcs8::EncodePublicKey as _;
-                #[allow(clippy::expect_used)]
-                k.to_public_key_der()
-                    .expect("rsa SPKI encoding is infallible")
-                    .to_vec()
-            }
-        }
-    }
-
-    pub fn key_type(&self) -> KeyType {
-        match self {
-            AuthPublicKey::Ed25519(_) => KeyType::Ed25519,
-            AuthPublicKey::EcdsaSecp256k1(_) => KeyType::EcdsaSecp256k1,
-            AuthPublicKey::Rsa(_) => KeyType::Rsa,
-        }
-    }
-}
-
-impl TryFrom<(KeyType, Vec<u8>)> for AuthPublicKey {
-    type Error = &'static str;
-
-    fn try_from(value: (KeyType, Vec<u8>)) -> Result<Self, Self::Error> {
-        let (key_type, bytes) = value;
-        match key_type {
-            KeyType::Ed25519 => {
-                let bytes: [u8; 32] = bytes.try_into().map_err(|_| "invalid Ed25519 key length")?;
-                let key = ed25519_dalek::VerifyingKey::from_bytes(&bytes)
-                    .map_err(|_e| "invalid Ed25519 key")?;
-                Ok(AuthPublicKey::Ed25519(key))
-            }
-            KeyType::EcdsaSecp256k1 => {
-                let point =
-                    k256::EncodedPoint::from_bytes(&bytes).map_err(|_e| "invalid ECDSA key")?;
-                let key = k256::ecdsa::VerifyingKey::from_encoded_point(&point)
-                    .map_err(|_e| "invalid ECDSA key")?;
-                Ok(AuthPublicKey::EcdsaSecp256k1(key))
-            }
-            KeyType::Rsa => {
-                use rsa::pkcs8::DecodePublicKey as _;
-                let key = rsa::RsaPublicKey::from_public_key_der(&bytes)
-                    .map_err(|_e| "invalid RSA key")?;
-                Ok(AuthPublicKey::Rsa(key))
-            }
-        }
-    }
-}
-
-// Messages, sent by user agent to connection client without having a request
-#[derive(Debug)]
-pub enum OutOfBand {
-    ClientConnectionRequest { profile: ClientProfile },
-    ClientConnectionCancel { pubkey: ed25519_dalek::VerifyingKey },
-}
-
-pub struct UserAgentConnection {
-    pub(crate) db: db::DatabasePool,
-    pub(crate) actors: GlobalActors,
-}
-
-impl UserAgentConnection {
-    pub fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
-        Self { db, actors }
-    }
-}
-
-pub mod auth;
-pub mod session;
-
-pub use auth::authenticate;
-pub use session::UserAgentSession;

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

@@ -1,510 +0,0 @@
-use std::sync::Mutex;
-
-use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
-use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
-use diesel::{ExpressionMethods as _, QueryDsl as _, SelectableHelper};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::error::SendError;
-use kameo::messages;
-use kameo::prelude::Context;
-use tracing::{error, info};
-use x25519_dalek::{EphemeralSecret, PublicKey};
-
-use crate::actors::flow_coordinator::client_connect_approval::ClientApprovalAnswer;
-use crate::actors::keyholder::KeyHolderState;
-use crate::actors::user_agent::session::Error;
-use crate::db::models::{
-    EvmWalletAccess, NewEvmWalletAccess, ProgramClient, ProgramClientMetadata,
-};
-use crate::evm::policies::{Grant, SpecificGrant};
-use crate::safe_cell::SafeCell;
-use crate::{
-    actors::{
-        evm::{
-            ClientSignTransaction, Generate, ListWallets, SignTransactionError as EvmSignError,
-            UseragentCreateGrant, UseragentDeleteGrant, UseragentListGrants,
-        },
-        keyholder::{self, Bootstrap, TryUnseal},
-        user_agent::session::{
-            UserAgentSession,
-            state::{UnsealContext, UserAgentEvents, UserAgentStates},
-        },
-    },
-    safe_cell::SafeCellHandle as _,
-};
-
-impl UserAgentSession {
-    fn take_unseal_secret(&mut self) -> Result<(EphemeralSecret, PublicKey), Error> {
-        let UserAgentStates::WaitingForUnsealKey(unseal_context) = self.state.state() else {
-            error!("Received encrypted key in invalid state");
-            return Err(Error::internal("Invalid state for unseal encrypted key"));
-        };
-
-        let ephemeral_secret = {
-            #[allow(
-                clippy::unwrap_used,
-                reason = "Mutex poison is unrecoverable and should panic"
-            )]
-            let mut secret_lock = unseal_context.secret.lock().unwrap();
-            let secret = secret_lock.take();
-            match secret {
-                Some(secret) => secret,
-                None => {
-                    drop(secret_lock);
-                    error!("Ephemeral secret already taken");
-                    return Err(Error::internal("Ephemeral secret already taken"));
-                }
-            }
-        };
-
-        Ok((ephemeral_secret, unseal_context.client_public_key))
-    }
-
-    fn decrypt_client_key_material(
-        ephemeral_secret: EphemeralSecret,
-        client_public_key: PublicKey,
-        nonce: &[u8],
-        ciphertext: &[u8],
-        associated_data: &[u8],
-    ) -> Result<SafeCell<Vec<u8>>, ()> {
-        let nonce = XNonce::from_slice(nonce);
-
-        let shared_secret = ephemeral_secret.diffie_hellman(&client_public_key);
-        let cipher = XChaCha20Poly1305::new(shared_secret.as_bytes().into());
-
-        let mut key_buffer = SafeCell::new(ciphertext.to_vec());
-
-        let decryption_result = key_buffer.write_inline(|write_handle| {
-            cipher.decrypt_in_place(nonce, associated_data, write_handle)
-        });
-
-        match decryption_result {
-            Ok(_) => Ok(key_buffer),
-            Err(err) => {
-                error!(?err, "Failed to decrypt encrypted key material");
-                Err(())
-            }
-        }
-    }
-}
-
-pub struct UnsealStartResponse {
-    pub server_pubkey: PublicKey,
-}
-
-#[derive(Debug, Error)]
-pub enum UnsealError {
-    #[error("Invalid key provided for unsealing")]
-    InvalidKey,
-    #[error("Internal error during unsealing process")]
-    General(#[from] super::Error),
-}
-
-#[derive(Debug, Error)]
-pub enum BootstrapError {
-    #[error("Invalid key provided for bootstrapping")]
-    InvalidKey,
-    #[error("Vault is already bootstrapped")]
-    AlreadyBootstrapped,
-
-    #[error("Internal error during bootstrapping process")]
-    General(#[from] super::Error),
-}
-
-#[derive(Debug, Error)]
-pub enum SignTransactionError {
-    #[error("Policy evaluation failed")]
-    Vet(#[from] crate::evm::VetError),
-
-    #[error("Internal signing error")]
-    Internal,
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub async fn handle_unseal_request(
-        &mut self,
-        client_pubkey: x25519_dalek::PublicKey,
-    ) -> Result<UnsealStartResponse, Error> {
-        let secret = EphemeralSecret::random();
-        let public_key = PublicKey::from(&secret);
-
-        self.transition(UserAgentEvents::UnsealRequest(UnsealContext {
-            secret: Mutex::new(Some(secret)),
-            client_public_key: client_pubkey,
-        }))?;
-
-        Ok(UnsealStartResponse {
-            server_pubkey: public_key,
-        })
-    }
-
-    #[message]
-    pub async fn handle_unseal_encrypted_key(
-        &mut self,
-        nonce: Vec<u8>,
-        ciphertext: Vec<u8>,
-        associated_data: Vec<u8>,
-    ) -> Result<(), UnsealError> {
-        let (ephemeral_secret, client_public_key) = match self.take_unseal_secret() {
-            Ok(values) => values,
-            Err(Error::State) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(UnsealError::InvalidKey);
-            }
-            Err(_err) => {
-                return Err(Error::internal("Failed to take unseal secret").into());
-            }
-        };
-
-        let seal_key_buffer = match Self::decrypt_client_key_material(
-            ephemeral_secret,
-            client_public_key,
-            &nonce,
-            &ciphertext,
-            &associated_data,
-        ) {
-            Ok(buffer) => buffer,
-            Err(()) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(UnsealError::InvalidKey);
-            }
-        };
-
-        match self
-            .props
-            .actors
-            .key_holder
-            .ask(TryUnseal {
-                seal_key_raw: seal_key_buffer,
-            })
-            .await
-        {
-            Ok(_) => {
-                info!("Successfully unsealed key with client-provided key");
-                self.transition(UserAgentEvents::ReceivedValidKey)?;
-                Ok(())
-            }
-            Err(SendError::HandlerError(keyholder::Error::InvalidKey)) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(UnsealError::InvalidKey)
-            }
-            Err(SendError::HandlerError(err)) => {
-                error!(?err, "Keyholder failed to unseal key");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(UnsealError::InvalidKey)
-            }
-            Err(err) => {
-                error!(?err, "Failed to send unseal request to keyholder");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(Error::internal("Vault actor error").into())
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_bootstrap_encrypted_key(
-        &mut self,
-        nonce: Vec<u8>,
-        ciphertext: Vec<u8>,
-        associated_data: Vec<u8>,
-    ) -> Result<(), BootstrapError> {
-        let (ephemeral_secret, client_public_key) = match self.take_unseal_secret() {
-            Ok(values) => values,
-            Err(Error::State) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(BootstrapError::InvalidKey);
-            }
-            Err(err) => return Err(err.into()),
-        };
-
-        let seal_key_buffer = match Self::decrypt_client_key_material(
-            ephemeral_secret,
-            client_public_key,
-            &nonce,
-            &ciphertext,
-            &associated_data,
-        ) {
-            Ok(buffer) => buffer,
-            Err(()) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(BootstrapError::InvalidKey);
-            }
-        };
-
-        match self
-            .props
-            .actors
-            .key_holder
-            .ask(Bootstrap {
-                seal_key_raw: seal_key_buffer,
-            })
-            .await
-        {
-            Ok(_) => {
-                info!("Successfully bootstrapped vault with client-provided key");
-                self.transition(UserAgentEvents::ReceivedValidKey)?;
-                Ok(())
-            }
-            Err(SendError::HandlerError(keyholder::Error::AlreadyBootstrapped)) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::AlreadyBootstrapped)
-            }
-            Err(SendError::HandlerError(err)) => {
-                error!(?err, "Keyholder failed to bootstrap vault");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::InvalidKey)
-            }
-            Err(err) => {
-                error!(?err, "Failed to send bootstrap request to keyholder");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::General(Error::internal(
-                    "Vault actor error",
-                )))
-            }
-        }
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<KeyHolderState, Error> {
-        use crate::actors::keyholder::GetState;
-
-        let vault_state = match self.props.actors.key_holder.ask(GetState {}).await {
-            Ok(state) => state,
-            Err(err) => {
-                error!(?err, actor = "useragent", "keyholder.query.failed");
-                return Err(Error::internal("Vault is in broken state"));
-            }
-        };
-
-        Ok(vault_state)
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub(crate) async fn handle_evm_wallet_create(&mut self) -> Result<(i32, Address), Error> {
-        match self.props.actors.evm.ask(Generate {}).await {
-            Ok(address) => Ok(address),
-            Err(SendError::HandlerError(err)) => Err(Error::internal(format!(
-                "EVM wallet generation failed: {err}"
-            ))),
-            Err(err) => {
-                error!(?err, "EVM actor unreachable during wallet create");
-                Err(Error::internal("EVM actor unreachable"))
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_evm_wallet_list(&mut self) -> Result<Vec<(i32, Address)>, Error> {
-        match self.props.actors.evm.ask(ListWallets {}).await {
-            Ok(wallets) => Ok(wallets),
-            Err(err) => {
-                error!(?err, "EVM wallet list failed");
-                Err(Error::internal("Failed to list EVM wallets"))
-            }
-        }
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub(crate) async fn handle_grant_list(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
-        match self.props.actors.evm.ask(UseragentListGrants {}).await {
-            Ok(grants) => Ok(grants),
-            Err(err) => {
-                error!(?err, "EVM grant list failed");
-                Err(Error::internal("Failed to list EVM grants"))
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_grant_create(
-        &mut self,
-        basic: crate::evm::policies::SharedGrantSettings,
-        grant: crate::evm::policies::SpecificGrant,
-    ) -> Result<i32, Error> {
-        match self
-            .props
-            .actors
-            .evm
-            .ask(UseragentCreateGrant { basic, grant })
-            .await
-        {
-            Ok(grant_id) => Ok(grant_id),
-            Err(err) => {
-                error!(?err, "EVM grant create failed");
-                Err(Error::internal("Failed to create EVM grant"))
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_grant_delete(&mut self, grant_id: i32) -> Result<(), Error> {
-        match self
-            .props
-            .actors
-            .evm
-            .ask(UseragentDeleteGrant { grant_id })
-            .await
-        {
-            Ok(()) => Ok(()),
-            Err(err) => {
-                error!(?err, "EVM grant delete failed");
-                Err(Error::internal("Failed to delete EVM grant"))
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_sign_transaction(
-        &mut self,
-        client_id: i32,
-        wallet_address: Address,
-        transaction: TxEip1559,
-    ) -> Result<Signature, SignTransactionError> {
-        match self
-            .props
-            .actors
-            .evm
-            .ask(ClientSignTransaction {
-                client_id,
-                wallet_address,
-                transaction,
-            })
-            .await
-        {
-            Ok(signature) => Ok(signature),
-            Err(SendError::HandlerError(EvmSignError::Vet(vet_error))) => {
-                Err(SignTransactionError::Vet(vet_error))
-            }
-            Err(err) => {
-                error!(?err, "EVM sign transaction failed in user-agent session");
-                Err(SignTransactionError::Internal)
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_grant_evm_wallet_access(
-        &mut self,
-        entries: Vec<NewEvmWalletAccess>,
-    ) -> Result<(), Error> {
-        let mut conn = self.props.db.get().await?;
-        conn.transaction(|conn| {
-            Box::pin(async move {
-                use crate::db::schema::evm_wallet_access;
-
-                for entry in entries {
-                    diesel::insert_into(evm_wallet_access::table)
-                        .values(&entry)
-                        .on_conflict_do_nothing()
-                        .execute(conn)
-                        .await?;
-                }
-
-                Result::<_, Error>::Ok(())
-            })
-        })
-        .await?;
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_revoke_evm_wallet_access(
-        &mut self,
-        entries: Vec<i32>,
-    ) -> Result<(), Error> {
-        let mut conn = self.props.db.get().await?;
-        conn.transaction(|conn| {
-            Box::pin(async move {
-                use crate::db::schema::evm_wallet_access;
-                for entry in entries {
-                    diesel::delete(evm_wallet_access::table)
-                        .filter(evm_wallet_access::wallet_id.eq(entry))
-                        .execute(conn)
-                        .await?;
-                }
-
-                Result::<_, Error>::Ok(())
-            })
-        })
-        .await?;
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_list_wallet_access(
-        &mut self,
-    ) -> Result<Vec<EvmWalletAccess>, Error> {
-        let mut conn = self.props.db.get().await?;
-        use crate::db::schema::evm_wallet_access;
-        let access_entries = evm_wallet_access::table
-            .select(EvmWalletAccess::as_select())
-            .load::<_>(&mut conn)
-            .await?;
-        Ok(access_entries)
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message(ctx)]
-    pub(crate) async fn handle_new_client_approve(
-        &mut self,
-        approved: bool,
-        pubkey: ed25519_dalek::VerifyingKey,
-        ctx: &mut Context<Self, Result<(), Error>>,
-    ) -> Result<(), Error> {
-        let pending_approval = match self.pending_client_approvals.remove(&pubkey) {
-            Some(approval) => approval,
-            None => {
-                error!("Received client connection response for unknown client");
-                return Err(Error::internal("Unknown client in connection response"));
-            }
-        };
-
-        pending_approval
-            .controller
-            .tell(ClientApprovalAnswer { approved })
-            .await
-            .map_err(|err| {
-                error!(
-                    ?err,
-                    "Failed to send client approval response to controller"
-                );
-                Error::internal("Failed to send client approval response to controller")
-            })?;
-
-        ctx.actor_ref().unlink(&pending_approval.controller).await;
-
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_sdk_client_list(
-        &mut self,
-    ) -> Result<Vec<(ProgramClient, ProgramClientMetadata)>, Error> {
-        use crate::db::schema::{client_metadata, program_client};
-        let mut conn = self.props.db.get().await?;
-
-        let clients = program_client::table
-            .inner_join(client_metadata::table)
-            .select((
-                ProgramClient::as_select(),
-                ProgramClientMetadata::as_select(),
-            ))
-            .load::<(ProgramClient, ProgramClientMetadata)>(&mut conn)
-            .await?;
-
-        Ok(clients)
-    }
-}

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

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

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

@@ -0,0 +1,57 @@
+use alloy::primitives::map::HashMap;
+use arbiter_crypto::authn;
+use kameo::{error::Infallible, prelude::*};
+
+use crate::{db::DatabasePool, peers::user_agent::{Credentials, UserAgentSession}};
+
+use super::vault::{Vault, events as vault_events};
+
+pub struct Args {
+    pub vault: ActorRef<Vault>,
+    pub pool: DatabasePool,
+}
+
+pub struct UserAgentRegistry {
+    vault: ActorRef<Vault>,
+    pool: DatabasePool,
+    connected: HashMap<Credentials, ActorRef<UserAgentSession>>,
+}
+
+impl Message<vault_events::Bootstrapped> for UserAgentRegistry {
+    type Reply = ();
+
+    async fn handle(
+        &mut self,
+        msg: vault_events::Bootstrapped,
+        ctx: &mut Context<Self, Self::Reply>,
+    ) -> Self::Reply {
+        todo!()
+    }
+}
+
+impl Message<vault_events::Unsealed> for UserAgentRegistry {
+    type Reply = ();
+
+    async fn handle(
+        &mut self,
+        msg: vault_events::Unsealed,
+        ctx: &mut Context<Self, Self::Reply>,
+    ) -> Self::Reply {
+        todo!()
+    }
+}
+impl Actor for UserAgentRegistry {
+    type Args = Args;
+
+    type Error = Infallible;
+
+    async fn on_start(args: Self::Args, actor_ref: ActorRef<Self>) -> Result<Self, Self::Error> {
+        Ok(Self {
+            vault: args.vault,
+            pool: args.pool,
+            connected: HashMap::default(),
+        })
+    }
+
+    
+}

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

@@ -4,47 +4,44 @@ use diesel::{
     dsl::{insert_into, update},
 };
 use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::{Actor, Reply, messages};
+use hmac::Mac as _;
+use kameo::{Actor, Reply, actor::ActorRef, messages};
+use kameo_actors::message_bus::{MessageBus, Publish};
 use strum::{EnumDiscriminants, IntoDiscriminant};
 use tracing::{error, info};
 
-use crate::{
-    crypto::{
-        KeyCell, derive_key,
-        encryption::v1::{self, Nonce},
-        integrity::v1::compute_integrity_tag,
-    },
-    safe_cell::SafeCell,
+use crate::crypto::{
+    KeyCell, derive_key,
+    encryption::v1::{self, Nonce},
+    integrity::v1::HmacSha256,
 };
-use crate::{
-    db::{
-        self,
-        models::{self, RootKeyHistory},
-        schema::{self},
-    },
-    safe_cell::SafeCellHandle as _,
+use crate::db::{
+    self,
+    models::{self, RootKeyHistory},
+    schema::{self},
 };
+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,
 
@@ -64,18 +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?;
 
@@ -93,10 +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?;
@@ -133,6 +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) {
@@ -185,12 +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(())
     }
@@ -237,40 +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(())
     }
 
-    // Signs a generic integrity payload using the vault-derived integrity key
-    #[message]
-    pub fn sign_integrity_tag(
-        &mut self,
-        purpose_tag: Vec<u8>,
-        data_parts: Vec<Vec<u8>>,
-    ) -> Result<Vec<u8>, Error> {
-        let State::Unsealed { root_key, .. } = &mut self.state else {
-            return Err(Error::NotBootstrapped);
-        };
-
-        let tag =
-            compute_integrity_tag(root_key, &purpose_tag, data_parts.iter().map(Vec::as_slice));
-        Ok(tag.to_vec())
-    }
-
     #[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?;
@@ -298,14 +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
@@ -335,22 +337,69 @@ impl KeyHolder {
     }
 
     #[message]
-    pub fn get_state(&self) -> KeyHolderState {
+    pub fn get_state(&self) -> VaultState {
         self.state.discriminant()
     }
 
     #[message]
-    pub fn seal(&mut self) -> Result<(), Error> {
-        let State::Unsealed {
+    pub fn sign_integrity(&mut self, mac_input: Vec<u8>) -> Result<(i32, Vec<u8>), Error> {
+        let Unsealed {
+            root_key,
+            root_key_history_id,
+        } = Self::expect_unsealed(&mut self.state)?;
+
+        let mut hmac = root_key
+            .0
+            .read_inline(|k| match HmacSha256::new_from_slice(k) {
+                Ok(v) => v,
+                Err(_) => unreachable!("HMAC accepts keys of any size"),
+            });
+        hmac.update(&root_key_history_id.to_be_bytes());
+        hmac.update(&mac_input);
+
+        let mac = hmac.finalize().into_bytes().to_vec();
+        Ok((*root_key_history_id, mac))
+    }
+
+    #[message]
+    pub fn verify_integrity(
+        &mut self,
+        mac_input: Vec<u8>,
+        expected_mac: Vec<u8>,
+        key_version: i32,
+    ) -> Result<bool, Error> {
+        let Unsealed {
+            root_key,
+            root_key_history_id,
+        } = Self::expect_unsealed(&mut self.state)?;
+
+        if *root_key_history_id != key_version {
+            return Ok(false);
+        }
+
+        let mut hmac = root_key
+            .0
+            .read_inline(|k| match HmacSha256::new_from_slice(k) {
+                Ok(v) => v,
+                Err(_) => unreachable!("HMAC accepts keys of any size"),
+            });
+        hmac.update(&key_version.to_be_bytes());
+        hmac.update(&mac_input);
+
+        Ok(hmac.verify_slice(&expected_mac).is_ok())
+    }
+
+    #[message]
+    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(())
     }
 }
@@ -362,14 +411,17 @@ mod tests {
     use diesel_async::RunQueryDsl;
 
     use crate::{
+        actors::GlobalActors,
         db::{self},
-        safe_cell::SafeCell,
     };
+    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
@@ -381,17 +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/encryption/mod.rs

@@ -1 +1,3 @@
 pub mod v1;
+
+pub use v1::*;

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

@@ -59,10 +59,8 @@ mod tests {
     use std::ops::Deref as _;
 
     use super::*;
-    use crate::{
-        crypto::derive_key,
-        safe_cell::{SafeCell, SafeCellHandle as _},
-    };
+    use crate::crypto::derive_key;
+    use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 
     #[test]
     pub fn derive_seal_key_deterministic() {

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

@@ -1 +1,3 @@
 pub mod v1;
+
+pub use v1::*;

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

@@ -1,78 +1,349 @@
-use crate::{crypto::KeyCell, safe_cell::SafeCellHandle as _};
-use chacha20poly1305::Key;
-use hmac::Mac as _;
+use crate::{
+    actors::vault::{self, GetState},
+    crypto::integrity::hashing::Hashable,
+};
+use hmac::Hmac;
+use sha2::Sha256;
 
-pub const USERAGENT_INTEGRITY_DERIVE_TAG: &[u8] = "arbiter/useragent/integrity-key/v1".as_bytes();
-pub const USERAGENT_INTEGRITY_TAG: &[u8] = "arbiter/useragent/pubkey-entry/v1".as_bytes();
+use diesel::{ExpressionMethods as _, QueryDsl, dsl::insert_into, sqlite::Sqlite};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use kameo::{actor::ActorRef, error::SendError};
+use sha2::Digest as _;
 
-/// Computes an integrity tag for a specific domain and payload shape.
-pub fn compute_integrity_tag<'a, I>(
-    integrity_key: &mut KeyCell,
-    purpose_tag: &[u8],
-    data_parts: I,
-) -> [u8; 32]
-where
-    I: IntoIterator<Item = &'a [u8]>,
-{
-    type HmacSha256 = hmac::Hmac<sha2::Sha256>;
+pub mod hashing;
 
-    let mut output_tag = [0u8; 32];
-    integrity_key.0.read_inline(|integrity_key_bytes: &Key| {
-        let mut mac = <HmacSha256 as hmac::Mac>::new_from_slice(integrity_key_bytes.as_ref())
-            .expect("HMAC key initialization must not fail for 32-byte key");
-        mac.update(purpose_tag);
-        for data_part in data_parts {
-            mac.update(data_part);
+use crate::{
+    actors::vault::{SignIntegrity, Vault, VerifyIntegrity},
+    db::{
+        self,
+        models::{IntegrityEnvelope, NewIntegrityEnvelope},
+        schema::integrity_envelope,
+    },
+};
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("Database error: {0}")]
+    Database(#[from] db::DatabaseError),
+
+    #[error("Vault error: {0}")]
+    Vault(#[from] vault::Error),
+
+    #[error("Vault mailbox error")]
+    VaultSend,
+
+    #[error("Integrity envelope is missing for entity {entity_kind}")]
+    MissingEnvelope { entity_kind: &'static str },
+
+    #[error(
+        "Integrity payload version mismatch for entity {entity_kind}: expected {expected}, found {found}"
+    )]
+    PayloadVersionMismatch {
+        entity_kind: &'static str,
+        expected: i32,
+        found: i32,
+    },
+
+    #[error("Integrity MAC mismatch for entity {entity_kind}")]
+    MacMismatch { entity_kind: &'static str },
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum AttestationStatus {
+    Attested,
+    Unavailable,
+}
+
+pub const CURRENT_PAYLOAD_VERSION: i32 = 1;
+pub const INTEGRITY_SUBKEY_TAG: &[u8] = b"arbiter/db-integrity-key/v1";
+
+pub type HmacSha256 = Hmac<Sha256>;
+
+pub trait Integrable: Hashable {
+    const KIND: &'static str;
+    const VERSION: i32 = 1;
+}
+
+fn payload_hash(payload: &impl Hashable) -> [u8; 32] {
+    let mut hasher = Sha256::new();
+    payload.hash(&mut hasher);
+    hasher.finalize().into()
+}
+
+fn push_len_prefixed(out: &mut Vec<u8>, bytes: &[u8]) {
+    out.extend_from_slice(&(bytes.len() as u32).to_be_bytes());
+    out.extend_from_slice(bytes);
+}
+
+fn build_mac_input(
+    entity_kind: &str,
+    entity_id: &[u8],
+    payload_version: i32,
+    payload_hash: &[u8; 32],
+) -> Vec<u8> {
+    let mut out = Vec::with_capacity(8 + entity_kind.len() + entity_id.len() + 32);
+    push_len_prefixed(&mut out, entity_kind.as_bytes());
+    push_len_prefixed(&mut out, entity_id);
+    out.extend_from_slice(&payload_version.to_be_bytes());
+    out.extend_from_slice(payload_hash);
+    out
+}
+
+pub trait IntoId {
+    fn into_id(self) -> Vec<u8>;
+}
+
+impl IntoId for i32 {
+    fn into_id(self) -> Vec<u8> {
+        self.to_be_bytes().to_vec()
+    }
+}
+
+impl IntoId for &'_ [u8] {
+    fn into_id(self) -> Vec<u8> {
+        self.to_vec()
+    }
+}
+
+pub async fn sign_entity<E: Integrable>(
+    conn: &mut impl AsyncConnection<Backend = Sqlite>,
+    vault: &ActorRef<Vault>,
+    entity: &E,
+    entity_id: impl IntoId,
+) -> Result<(), Error> {
+    let payload_hash = payload_hash(&entity);
+
+    let entity_id = entity_id.into_id();
+
+    let mac_input = build_mac_input(E::KIND, &entity_id, E::VERSION, &payload_hash);
+
+    let (key_version, mac) =
+        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 {
+            entity_kind: E::KIND.to_owned(),
+            entity_id,
+            payload_version: E::VERSION,
+            key_version,
+            mac: mac.to_vec(),
+        })
+        .on_conflict((
+            integrity_envelope::entity_id,
+            integrity_envelope::entity_kind,
+        ))
+        .do_update()
+        .set((
+            integrity_envelope::payload_version.eq(E::VERSION),
+            integrity_envelope::key_version.eq(key_version),
+            integrity_envelope::mac.eq(mac),
+        ))
+        .execute(conn)
+        .await
+        .map_err(db::DatabaseError::from)?;
+
+    Ok(())
+}
+
+pub async fn verify_entity<E: Integrable>(
+    conn: &mut impl AsyncConnection<Backend = Sqlite>,
+    vault: &ActorRef<Vault>,
+    entity: &E,
+    entity_id: impl IntoId,
+) -> Result<AttestationStatus, Error> {
+    let entity_id = entity_id.into_id();
+    let envelope: IntegrityEnvelope = integrity_envelope::table
+        .filter(integrity_envelope::entity_kind.eq(E::KIND))
+        .filter(integrity_envelope::entity_id.eq(&entity_id))
+        .first(conn)
+        .await
+        .map_err(|err| match err {
+            diesel::result::Error::NotFound => Error::MissingEnvelope {
+                entity_kind: E::KIND,
+            },
+            other => Error::Database(db::DatabaseError::from(other)),
+        })?;
+
+    if envelope.payload_version != E::VERSION {
+        return Err(Error::PayloadVersionMismatch {
+            entity_kind: E::KIND,
+            expected: E::VERSION,
+            found: envelope.payload_version,
+        });
+    }
+
+    let payload_hash = payload_hash(&entity);
+    let mac_input = build_mac_input(E::KIND, &entity_id, envelope.payload_version, &payload_hash);
+
+    let result = vault
+        .ask(VerifyIntegrity {
+            mac_input,
+            expected_mac: envelope.mac,
+            key_version: envelope.key_version,
+        })
+        .await;
+
+    match result {
+        Ok(true) => Ok(AttestationStatus::Attested),
+        Ok(false) => Err(Error::MacMismatch {
+            entity_kind: E::KIND,
+        }),
+        Err(SendError::HandlerError(vault::Error::Sealed)) => {
+            Ok(AttestationStatus::Unavailable)
         }
-        output_tag.copy_from_slice(&mac.finalize().into_bytes());
-    });
+        Err(_) => Err(Error::VaultSend),
+    }
+}
 
-    output_tag
+pub async fn is_signing_available(vault: &ActorRef<Vault>) -> Result<bool, Error> {
+    let state = vault.ask(GetState).await.map_err(|_| Error::VaultSend)?;
+    Ok(matches!(state, vault::VaultState::Unsealed))
 }
 
 #[cfg(test)]
 mod tests {
+    use diesel::{ExpressionMethods as _, QueryDsl};
+    use diesel_async::RunQueryDsl;
+    use kameo::{actor::ActorRef, prelude::Spawn};
+
+    use sha2::Digest;
+
     use crate::{
-        crypto::{derive_key, encryption::v1::generate_salt},
-        safe_cell::{SafeCell, SafeCellHandle as _},
+        actors::{
+            GlobalActors,
+            vault::{Bootstrap, Vault},
+        },
+        db::{self, schema},
     };
+    use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 
-    use super::{USERAGENT_INTEGRITY_TAG, compute_integrity_tag};
+    use super::hashing::Hashable;
+    use super::{Error, Integrable, sign_entity, verify_entity};
 
-    #[test]
-    pub fn integrity_tag_deterministic() {
-        let salt = generate_salt();
-        let mut integrity_key = derive_key(SafeCell::new(b"password".to_vec()), &salt);
-        let key_type = 1i32.to_be_bytes();
-        let t1 = compute_integrity_tag(
-            &mut integrity_key,
-            USERAGENT_INTEGRITY_TAG,
-            [key_type.as_slice(), b"pubkey".as_ref()],
-        );
-        let t2 = compute_integrity_tag(
-            &mut integrity_key,
-            USERAGENT_INTEGRITY_TAG,
-            [key_type.as_slice(), b"pubkey".as_ref()],
-        );
-        assert_eq!(t1, t2);
+    #[derive(Clone)]
+    struct DummyEntity {
+        payload_version: i32,
+        payload: Vec<u8>,
     }
 
-    #[test]
-    pub fn integrity_tag_changes_with_payload() {
-        let salt = generate_salt();
-        let mut integrity_key = derive_key(SafeCell::new(b"password".to_vec()), &salt);
-        let key_type_1 = 1i32.to_be_bytes();
-        let key_type_2 = 2i32.to_be_bytes();
-        let t1 = compute_integrity_tag(
-            &mut integrity_key,
-            USERAGENT_INTEGRITY_TAG,
-            [key_type_1.as_slice(), b"pubkey".as_ref()],
+    impl Hashable for DummyEntity {
+        fn hash<H: Digest>(&self, hasher: &mut H) {
+            self.payload_version.hash(hasher);
+            self.payload.hash(hasher);
+        }
+    }
+    impl Integrable for DummyEntity {
+        const KIND: &'static str = "dummy_entity";
+    }
+
+    async fn bootstrapped_vault(db: &db::DatabasePool) -> ActorRef<Vault> {
+        let actor = Vault::spawn(
+            Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+                .await
+                .unwrap(),
         );
-        let t2 = compute_integrity_tag(
-            &mut integrity_key,
-            USERAGENT_INTEGRITY_TAG,
-            [key_type_2.as_slice(), b"pubkey".as_ref()],
-        );
-        assert_ne!(t1, t2);
+        actor
+            .ask(Bootstrap {
+                seal_key_raw: SafeCell::new(b"integrity-test-seal-key".to_vec()),
+            })
+            .await
+            .unwrap();
+        actor
+    }
+
+    #[tokio::test]
+    async fn sign_writes_envelope_and_verify_passes() {
+        let db = db::create_test_pool().await;
+        let vault = bootstrapped_vault(&db).await;
+        let mut conn = db.get().await.unwrap();
+
+        const ENTITY_ID: &[u8] = b"entity-id-7";
+
+        let entity = DummyEntity {
+            payload_version: 1,
+            payload: b"payload-v1".to_vec(),
+        };
+
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap();
+
+        let count: i64 = schema::integrity_envelope::table
+            .filter(schema::integrity_envelope::entity_kind.eq("dummy_entity"))
+            .filter(schema::integrity_envelope::entity_id.eq(ENTITY_ID))
+            .count()
+            .get_result(&mut conn)
+            .await
+            .unwrap();
+
+        assert_eq!(count, 1, "envelope row must be created exactly once");
+        verify_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap();
+    }
+
+    #[tokio::test]
+    async fn tampered_mac_fails_verification() {
+        let db = db::create_test_pool().await;
+        let vault = bootstrapped_vault(&db).await;
+        let mut conn = db.get().await.unwrap();
+
+        const ENTITY_ID: &[u8] = b"entity-id-11";
+
+        let entity = DummyEntity {
+            payload_version: 1,
+            payload: b"payload-v1".to_vec(),
+        };
+
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap();
+
+        diesel::update(schema::integrity_envelope::table)
+            .filter(schema::integrity_envelope::entity_kind.eq("dummy_entity"))
+            .filter(schema::integrity_envelope::entity_id.eq(ENTITY_ID))
+            .set(schema::integrity_envelope::mac.eq(vec![0u8; 32]))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+
+        let err = verify_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap_err();
+        assert!(matches!(err, Error::MacMismatch { .. }));
+    }
+
+    #[tokio::test]
+    async fn changed_payload_fails_verification() {
+        let db = db::create_test_pool().await;
+        let vault = bootstrapped_vault(&db).await;
+        let mut conn = db.get().await.unwrap();
+
+        const ENTITY_ID: &[u8] = b"entity-id-21";
+
+        let entity = DummyEntity {
+            payload_version: 1,
+            payload: b"payload-v1".to_vec(),
+        };
+
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
+            .await
+            .unwrap();
+
+        let tampered = DummyEntity {
+            payload: b"payload-v1-but-tampered".to_vec(),
+            ..entity
+        };
+
+        let err = verify_entity(&mut conn, &vault, &tampered, ENTITY_ID)
+            .await
+            .unwrap_err();
+        assert!(matches!(err, Error::MacMismatch { .. }));
     }
 }

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

@@ -0,0 +1,107 @@
+use hmac::digest::Digest;
+use std::collections::HashSet;
+
+/// Deterministically hash a value by feeding its fields into the hasher in a consistent order.
+pub trait Hashable {
+    fn hash<H: Digest>(&self, hasher: &mut H);
+}
+
+macro_rules! impl_numeric {
+($($t:ty),*) => {
+    $(
+        impl Hashable for $t {
+            fn hash<H: Digest>(&self, hasher: &mut H) {
+                hasher.update(&self.to_be_bytes());
+            }
+        }
+    )*
+};
+}
+
+impl_numeric!(u8, u16, u32, u64, i8, i16, i32, i64);
+
+impl Hashable for &[u8] {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        hasher.update(self);
+    }
+}
+
+impl Hashable for String {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        hasher.update(self.as_bytes());
+    }
+}
+
+impl<T: Hashable + PartialOrd> Hashable for Vec<T> {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        let ref_sorted = {
+            let mut sorted = self.iter().collect::<Vec<_>>();
+            sorted.sort_by(|a, b| a.partial_cmp(b).unwrap());
+            sorted
+        };
+        for item in ref_sorted {
+            item.hash(hasher);
+        }
+    }
+}
+
+impl<T: Hashable + PartialOrd> Hashable for HashSet<T> {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        let ref_sorted = {
+            let mut sorted = self.iter().collect::<Vec<_>>();
+            sorted.sort_by(|a, b| a.partial_cmp(b).unwrap());
+            sorted
+        };
+        for item in ref_sorted {
+            item.hash(hasher);
+        }
+    }
+}
+
+impl<T: Hashable> Hashable for Option<T> {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        match self {
+            Some(value) => {
+                hasher.update([1]);
+                value.hash(hasher);
+            }
+            None => hasher.update([0]),
+        }
+    }
+}
+
+impl<T: Hashable> Hashable for Box<T> {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        self.as_ref().hash(hasher);
+    }
+}
+
+impl<T: Hashable> Hashable for &T {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        (*self).hash(hasher);
+    }
+}
+
+impl Hashable for alloy::primitives::Address {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        hasher.update(self.as_slice());
+    }
+}
+
+impl Hashable for alloy::primitives::U256 {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        hasher.update(self.to_be_bytes::<32>());
+    }
+}
+
+impl Hashable for chrono::Duration {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        hasher.update(self.num_seconds().to_be_bytes());
+    }
+}
+
+impl Hashable for chrono::DateTime<chrono::Utc> {
+    fn hash<H: Digest>(&self, hasher: &mut H) {
+        hasher.update(self.timestamp_millis().to_be_bytes());
+    }
+}

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

@@ -10,7 +10,7 @@ use rand::{
     rngs::{StdRng, SysRng},
 };
 
-use crate::safe_cell::{SafeCell, SafeCellHandle as _};
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 
 pub mod encryption;
 pub mod integrity;
@@ -102,11 +102,21 @@ impl KeyCell {
     }
 }
 
-/// User password might be of different length, have not enough entropy, etc...
 /// Derive a fixed-length key from the password using Argon2id, which is designed for password hashing and key derivation.
 pub fn derive_key(mut password: SafeCell<Vec<u8>>, salt: &Salt) -> KeyCell {
+    let params = {
+        #[cfg(debug_assertions)]
+        {
+            argon2::Params::new(8, 1, 1, None).unwrap()
+        }
+
+        #[cfg(not(debug_assertions))]
+        {
+            argon2::Params::new(262_144, 3, 4, None).unwrap()
+        }
+    };
+
     #[allow(clippy::unwrap_used)]
-    let params = argon2::Params::new(262_144, 3, 4, None).unwrap();
     let hasher = Argon2::new(Algorithm::Argon2id, argon2::Version::V0x13, params);
     let mut key = SafeCell::new(Key::default());
     password.read_inline(|password_source| {
@@ -131,7 +141,7 @@ mod tests {
         derive_key,
         encryption::v1::{Nonce, generate_salt},
     };
-    use crate::safe_cell::{SafeCell, SafeCellHandle as _};
+    use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 
     #[test]
     pub fn encrypt_decrypt() {

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

@@ -133,6 +133,7 @@ pub async fn create_pool(url: Option<&str>) -> Result<DatabasePool, DatabaseSetu
     Ok(pool)
 }
 
+#[mutants::skip]
 pub async fn create_test_pool() -> DatabasePool {
     use rand::distr::{Alphanumeric, SampleString as _};
 

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

@@ -5,7 +5,7 @@ use crate::db::schema::{
     self, aead_encrypted, arbiter_settings, evm_basic_grant, evm_ether_transfer_grant,
     evm_ether_transfer_grant_target, evm_ether_transfer_limit, evm_token_transfer_grant,
     evm_token_transfer_log, evm_token_transfer_volume_limit, evm_transaction_log, evm_wallet,
-    root_key_history, tls_history,
+    integrity_envelope, root_key_history, tls_history,
 };
 use chrono::{DateTime, Utc};
 use diesel::{prelude::*, sqlite::Sqlite};
@@ -72,40 +72,6 @@ pub mod types {
             Ok(SqliteTimestamp(datetime))
         }
     }
-
-    /// Key algorithm stored in the `useragent_client.key_type` column.
-    /// Values must stay stable — they are persisted in the database.
-    #[derive(Debug, Clone, Copy, PartialEq, Eq, FromSqlRow, AsExpression, strum::FromRepr)]
-    #[diesel(sql_type = Integer)]
-    #[repr(i32)]
-    pub enum KeyType {
-        Ed25519 = 1,
-        EcdsaSecp256k1 = 2,
-        Rsa = 3,
-    }
-
-    impl ToSql<Integer, Sqlite> for KeyType {
-        fn to_sql<'b>(
-            &'b self,
-            out: &mut diesel::serialize::Output<'b, '_, Sqlite>,
-        ) -> diesel::serialize::Result {
-            out.set_value(*self as i32);
-            Ok(IsNull::No)
-        }
-    }
-
-    impl FromSql<Integer, Sqlite> for KeyType {
-        fn from_sql(
-            mut bytes: <Sqlite as diesel::backend::Backend>::RawValue<'_>,
-        ) -> diesel::deserialize::Result<Self> {
-            let Some(SqliteType::Long) = bytes.value_type() else {
-                return Err("Expected Integer for KeyType".into());
-            };
-            let discriminant = bytes.read_long();
-            KeyType::from_repr(discriminant as i32)
-                .ok_or_else(|| format!("Unknown KeyType discriminant: {discriminant}").into())
-        }
-    }
 }
 pub use types::*;
 
@@ -242,10 +208,8 @@ pub struct UseragentClient {
     pub id: i32,
     pub nonce: i32,
     pub public_key: Vec<u8>,
-    pub pubkey_integrity_tag: Option<Vec<u8>>,
     pub created_at: SqliteTimestamp,
     pub updated_at: SqliteTimestamp,
-    pub key_type: KeyType,
 }
 
 #[derive(Models, Queryable, Debug, Insertable, Selectable)]
@@ -377,3 +341,22 @@ pub struct EvmTokenTransferLog {
     pub value: Vec<u8>,
     pub created_at: SqliteTimestamp,
 }
+
+#[derive(Models, Queryable, Debug, Insertable, Selectable)]
+#[diesel(table_name = integrity_envelope, check_for_backend(Sqlite))]
+#[view(
+    NewIntegrityEnvelope,
+    derive(Insertable),
+    omit(id, signed_at, created_at),
+    attributes_with = "deriveless"
+)]
+pub struct IntegrityEnvelope {
+    pub id: i32,
+    pub entity_kind: String,
+    pub entity_id: Vec<u8>,
+    pub payload_version: i32,
+    pub key_version: i32,
+    pub mac: Vec<u8>,
+    pub signed_at: SqliteTimestamp,
+    pub created_at: SqliteTimestamp,
+}

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

@@ -139,6 +139,19 @@ diesel::table! {
     }
 }
 
+diesel::table! {
+    integrity_envelope (id) {
+        id -> Integer,
+        entity_kind -> Text,
+        entity_id -> Binary,
+        payload_version -> Integer,
+        key_version -> Integer,
+        mac -> Binary,
+        signed_at -> Integer,
+        created_at -> Integer,
+    }
+}
+
 diesel::table! {
     program_client (id) {
         id -> Integer,
@@ -178,7 +191,6 @@ diesel::table! {
         id -> Integer,
         nonce -> Integer,
         public_key -> Binary,
-        pubkey_integrity_tag -> Nullable<Binary>,
         key_type -> Integer,
         created_at -> Integer,
         updated_at -> Integer,
@@ -220,6 +232,7 @@ diesel::allow_tables_to_appear_in_same_query!(
     evm_transaction_log,
     evm_wallet,
     evm_wallet_access,
+    integrity_envelope,
     program_client,
     root_key_history,
     tls_history,

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

@@ -8,8 +8,11 @@ use alloy::{
 use chrono::Utc;
 use diesel::{ExpressionMethods as _, QueryDsl as _, QueryResult, insert_into, sqlite::Sqlite};
 use diesel_async::{AsyncConnection, RunQueryDsl};
+use kameo::actor::ActorRef;
 
 use crate::{
+    actors::vault::Vault,
+    crypto::integrity,
     db::{
         self, DatabaseError,
         models::{
@@ -18,8 +21,8 @@ use crate::{
         schema::{self, evm_transaction_log},
     },
     evm::policies::{
-        DatabaseID, EvalContext, EvalViolation, FullGrant, Grant, Policy, SharedGrantSettings,
-        SpecificGrant, SpecificMeaning, ether_transfer::EtherTransfer,
+        CombinedSettings, DatabaseID, EvalContext, EvalViolation, Grant, Policy,
+        SharedGrantSettings, SpecificGrant, SpecificMeaning, ether_transfer::EtherTransfer,
         token_transfers::TokenTransfer,
     },
 };
@@ -36,6 +39,9 @@ pub enum PolicyError {
     Violations(Vec<EvalViolation>),
     #[error("No matching grant found")]
     NoMatchingGrant,
+
+    #[error("Integrity error: {0}")]
+    Integrity(#[from] integrity::Error),
 }
 
 #[derive(Debug, thiserror::Error)]
@@ -57,6 +63,15 @@ pub enum AnalyzeError {
     UnsupportedTransactionType,
 }
 
+#[derive(Debug, thiserror::Error)]
+pub enum ListError {
+    #[error("Database error")]
+    Database(#[from] crate::db::DatabaseError),
+
+    #[error("Integrity verification failed for grant")]
+    Integrity(#[from] integrity::Error),
+}
+
 /// Controls whether a transaction should be executed or only validated
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum RunKind {
@@ -75,6 +90,14 @@ async fn check_shared_constraints(
     let mut violations = Vec::new();
     let now = Utc::now();
 
+    if shared.chain != context.chain {
+        violations.push(EvalViolation::MismatchingChainId {
+            expected: shared.chain,
+            actual: context.chain,
+        });
+        return Ok(violations);
+    }
+
     // Validity window
     if shared.valid_from.is_some_and(|t| now < t) || shared.valid_until.is_some_and(|t| now > t) {
         violations.push(EvalViolation::InvalidTime);
@@ -115,6 +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,
+    vault: ActorRef<Vault>,
 }
 
 impl Engine {
@@ -123,7 +147,10 @@ impl Engine {
         context: EvalContext,
         meaning: &P::Meaning,
         run_kind: RunKind,
-    ) -> Result<(), PolicyError> {
+    ) -> Result<(), PolicyError>
+    where
+        P::Settings: Clone,
+    {
         let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
 
         let grant = P::try_find_grant(&context, &mut conn)
@@ -131,10 +158,16 @@ impl Engine {
             .map_err(DatabaseError::from)?
             .ok_or(PolicyError::NoMatchingGrant)?;
 
-        let mut violations =
-            check_shared_constraints(&context, &grant.shared, grant.shared_grant_id, &mut conn)
-                .await
-                .map_err(DatabaseError::from)?;
+        integrity::verify_entity(&mut conn, &self.vault, &grant.settings, grant.id).await?;
+
+        let mut violations = check_shared_constraints(
+            &context,
+            &grant.settings.shared,
+            grant.common_settings_id,
+            &mut conn,
+        )
+        .await
+        .map_err(DatabaseError::from)?;
         violations.extend(
             P::evaluate(&context, meaning, &grant, &mut conn)
                 .await
@@ -143,12 +176,14 @@ impl Engine {
 
         if !violations.is_empty() {
             return Err(PolicyError::Violations(violations));
-        } else if run_kind == RunKind::Execution {
+        }
+
+        if run_kind == RunKind::Execution {
             conn.transaction(|conn| {
                 Box::pin(async move {
                     let log_id: i32 = insert_into(evm_transaction_log::table)
                         .values(&NewEvmTransactionLog {
-                            grant_id: grant.shared_grant_id,
+                            grant_id: grant.common_settings_id,
                             wallet_access_id: context.target.id,
                             chain_id: context.chain as i32,
                             eth_value: utils::u256_to_bytes(context.value).to_vec(),
@@ -172,15 +207,19 @@ impl Engine {
 }
 
 impl Engine {
-    pub fn new(db: db::DatabasePool) -> Self {
-        Self { db }
+    pub fn new(db: db::DatabasePool, vault: ActorRef<Vault>) -> Self {
+        Self { db, vault }
     }
 
     pub async fn create_grant<P: Policy>(
         &self,
-        full_grant: FullGrant<P::Settings>,
-    ) -> Result<i32, DatabaseError> {
+        full_grant: CombinedSettings<P::Settings>,
+    ) -> Result<i32, DatabaseError>
+    where
+        P::Settings: Clone,
+    {
         let mut conn = self.db.get().await?;
+        let vault = self.vault.clone();
 
         let id = conn
             .transaction(|conn| {
@@ -189,25 +228,25 @@ impl Engine {
 
                     let basic_grant: EvmBasicGrant = insert_into(evm_basic_grant::table)
                         .values(&NewEvmBasicGrant {
-                            chain_id: full_grant.basic.chain as i32,
-                            wallet_access_id: full_grant.basic.wallet_access_id,
-                            valid_from: full_grant.basic.valid_from.map(SqliteTimestamp),
-                            valid_until: full_grant.basic.valid_until.map(SqliteTimestamp),
+                            chain_id: full_grant.shared.chain as i32,
+                            wallet_access_id: full_grant.shared.wallet_access_id,
+                            valid_from: full_grant.shared.valid_from.map(SqliteTimestamp),
+                            valid_until: full_grant.shared.valid_until.map(SqliteTimestamp),
                             max_gas_fee_per_gas: full_grant
-                                .basic
+                                .shared
                                 .max_gas_fee_per_gas
                                 .map(|fee| utils::u256_to_bytes(fee).to_vec()),
                             max_priority_fee_per_gas: full_grant
-                                .basic
+                                .shared
                                 .max_priority_fee_per_gas
                                 .map(|fee| utils::u256_to_bytes(fee).to_vec()),
                             rate_limit_count: full_grant
-                                .basic
+                                .shared
                                 .rate_limit
                                 .as_ref()
                                 .map(|rl| rl.count as i32),
                             rate_limit_window_secs: full_grant
-                                .basic
+                                .shared
                                 .rate_limit
                                 .as_ref()
                                 .map(|rl| rl.window.num_seconds() as i32),
@@ -217,7 +256,13 @@ impl Engine {
                         .get_result(conn)
                         .await?;
 
-                    P::create_grant(&basic_grant, &full_grant.specific, conn).await
+                    P::create_grant(&basic_grant, &full_grant.specific, conn).await?;
+
+                    integrity::sign_entity(conn, &vault, &full_grant, basic_grant.id)
+                        .await
+                        .map_err(|_| diesel::result::Error::RollbackTransaction)?;
+
+                    QueryResult::Ok(basic_grant.id)
                 })
             })
             .await?;
@@ -225,33 +270,36 @@ impl Engine {
         Ok(id)
     }
 
-    pub async fn list_all_grants(&self) -> Result<Vec<Grant<SpecificGrant>>, DatabaseError> {
-        let mut conn = self.db.get().await?;
+    async fn list_one_kind<Kind: Policy, Y>(
+        &self,
+        conn: &mut impl AsyncConnection<Backend = Sqlite>,
+    ) -> Result<impl Iterator<Item = Grant<Y>>, ListError>
+    where
+        Y: From<Kind::Settings>,
+    {
+        let all_grants = Kind::find_all_grants(conn)
+            .await
+            .map_err(DatabaseError::from)?;
+
+        // Verify integrity of all grants before returning any results
+        for grant in &all_grants {
+            integrity::verify_entity(conn, &self.vault, &grant.settings, grant.id).await?;
+        }
+
+        Ok(all_grants.into_iter().map(|g| Grant {
+            id: g.id,
+            common_settings_id: g.common_settings_id,
+            settings: g.settings.generalize(),
+        }))
+    }
+
+    pub async fn list_all_grants(&self) -> Result<Vec<Grant<SpecificGrant>>, ListError> {
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
 
         let mut grants: Vec<Grant<SpecificGrant>> = Vec::new();
 
-        grants.extend(
-            EtherTransfer::find_all_grants(&mut conn)
-                .await?
-                .into_iter()
-                .map(|g| Grant {
-                    id: g.id,
-                    shared_grant_id: g.shared_grant_id,
-                    shared: g.shared,
-                    settings: SpecificGrant::EtherTransfer(g.settings),
-                }),
-        );
-        grants.extend(
-            TokenTransfer::find_all_grants(&mut conn)
-                .await?
-                .into_iter()
-                .map(|g| Grant {
-                    id: g.id,
-                    shared_grant_id: g.shared_grant_id,
-                    shared: g.shared,
-                    settings: SpecificGrant::TokenTransfer(g.settings),
-                }),
-        );
+        grants.extend(self.list_one_kind::<EtherTransfer, _>(&mut conn).await?);
+        grants.extend(self.list_one_kind::<TokenTransfer, _>(&mut conn).await?);
 
         Ok(grants)
     }
@@ -297,3 +345,255 @@ impl Engine {
         Err(VetError::UnsupportedTransactionType)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use alloy::primitives::{Address, Bytes, U256, address};
+    use chrono::{Duration, Utc};
+    use diesel::{SelectableHelper, insert_into};
+    use diesel_async::RunQueryDsl;
+    use rstest::rstest;
+
+    use crate::db::{
+        self, DatabaseConnection,
+        models::{
+            EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, NewEvmTransactionLog, SqliteTimestamp,
+        },
+        schema::{evm_basic_grant, evm_transaction_log},
+    };
+    use crate::evm::policies::{
+        EvalContext, EvalViolation, SharedGrantSettings, TransactionRateLimit,
+    };
+
+    use super::check_shared_constraints;
+
+    const WALLET_ACCESS_ID: i32 = 1;
+    const CHAIN_ID: u64 = 1;
+    const RECIPIENT: Address = address!("1111111111111111111111111111111111111111");
+
+    fn context() -> EvalContext {
+        EvalContext {
+            target: EvmWalletAccess {
+                id: WALLET_ACCESS_ID,
+                wallet_id: 10,
+                client_id: 20,
+                created_at: SqliteTimestamp(Utc::now()),
+            },
+            chain: CHAIN_ID,
+            to: RECIPIENT,
+            value: U256::ZERO,
+            calldata: Bytes::new(),
+            max_fee_per_gas: 100,
+            max_priority_fee_per_gas: 10,
+        }
+    }
+
+    fn shared_settings() -> SharedGrantSettings {
+        SharedGrantSettings {
+            wallet_access_id: WALLET_ACCESS_ID,
+            chain: CHAIN_ID,
+            valid_from: None,
+            valid_until: None,
+            max_gas_fee_per_gas: None,
+            max_priority_fee_per_gas: None,
+            rate_limit: None,
+        }
+    }
+
+    async fn insert_basic_grant(
+        conn: &mut DatabaseConnection,
+        shared: &SharedGrantSettings,
+    ) -> EvmBasicGrant {
+        insert_into(evm_basic_grant::table)
+            .values(NewEvmBasicGrant {
+                wallet_access_id: shared.wallet_access_id,
+                chain_id: shared.chain as i32,
+                valid_from: shared.valid_from.map(SqliteTimestamp),
+                valid_until: shared.valid_until.map(SqliteTimestamp),
+                max_gas_fee_per_gas: shared
+                    .max_gas_fee_per_gas
+                    .map(|fee| super::utils::u256_to_bytes(fee).to_vec()),
+                max_priority_fee_per_gas: shared
+                    .max_priority_fee_per_gas
+                    .map(|fee| super::utils::u256_to_bytes(fee).to_vec()),
+                rate_limit_count: shared.rate_limit.as_ref().map(|limit| limit.count as i32),
+                rate_limit_window_secs: shared
+                    .rate_limit
+                    .as_ref()
+                    .map(|limit| limit.window.num_seconds() as i32),
+                revoked_at: None,
+            })
+            .returning(EvmBasicGrant::as_select())
+            .get_result(conn)
+            .await
+            .unwrap()
+    }
+
+    #[rstest]
+    #[case::matching_chain(CHAIN_ID, false)]
+    #[case::mismatching_chain(CHAIN_ID + 1, true)]
+    #[tokio::test]
+    async fn check_shared_constraints_enforces_chain_id(
+        #[case] context_chain: u64,
+        #[case] expect_mismatch: bool,
+    ) {
+        let db = db::create_test_pool().await;
+        let mut conn = db.get().await.unwrap();
+
+        let context = EvalContext {
+            chain: context_chain,
+            ..context()
+        };
+
+        let violations = check_shared_constraints(&context, &shared_settings(), 999, &mut *conn)
+            .await
+            .unwrap();
+
+        assert_eq!(
+            violations
+                .iter()
+                .any(|violation| matches!(violation, EvalViolation::MismatchingChainId { .. })),
+            expect_mismatch
+        );
+
+        if expect_mismatch {
+            assert_eq!(violations.len(), 1);
+        } else {
+            assert!(violations.is_empty());
+        }
+    }
+
+    #[rstest]
+    #[case::valid_from_in_bounds(Some(Utc::now() - Duration::hours(1)), None, false)]
+    #[case::valid_from_out_of_bounds(Some(Utc::now() + Duration::hours(1)), None, true)]
+    #[case::valid_until_in_bounds(None, Some(Utc::now() + Duration::hours(1)), false)]
+    #[case::valid_until_out_of_bounds(None, Some(Utc::now() - Duration::hours(1)), true)]
+    #[tokio::test]
+    async fn check_shared_constraints_enforces_validity_window(
+        #[case] valid_from: Option<chrono::DateTime<Utc>>,
+        #[case] valid_until: Option<chrono::DateTime<Utc>>,
+        #[case] expect_invalid_time: bool,
+    ) {
+        let db = db::create_test_pool().await;
+        let mut conn = db.get().await.unwrap();
+
+        let shared = SharedGrantSettings {
+            valid_from,
+            valid_until,
+            ..shared_settings()
+        };
+
+        let violations = check_shared_constraints(&context(), &shared, 999, &mut *conn)
+            .await
+            .unwrap();
+
+        assert_eq!(
+            violations
+                .iter()
+                .any(|violation| matches!(violation, EvalViolation::InvalidTime)),
+            expect_invalid_time
+        );
+
+        if expect_invalid_time {
+            assert_eq!(violations.len(), 1);
+        } else {
+            assert!(violations.is_empty());
+        }
+    }
+
+    #[rstest]
+    #[case::max_fee_within_limit(Some(U256::from(100u64)), None, 100, 10, false)]
+    #[case::max_fee_exceeded(Some(U256::from(99u64)), None, 100, 10, true)]
+    #[case::priority_fee_within_limit(None, Some(U256::from(10u64)), 100, 10, false)]
+    #[case::priority_fee_exceeded(None, Some(U256::from(9u64)), 100, 10, true)]
+    #[tokio::test]
+    async fn check_shared_constraints_enforces_gas_fee_caps(
+        #[case] max_gas_fee_per_gas: Option<U256>,
+        #[case] max_priority_fee_per_gas: Option<U256>,
+        #[case] actual_max_fee_per_gas: u128,
+        #[case] actual_max_priority_fee_per_gas: u128,
+        #[case] expect_gas_limit_violation: bool,
+    ) {
+        let db = db::create_test_pool().await;
+        let mut conn = db.get().await.unwrap();
+
+        let context = EvalContext {
+            max_fee_per_gas: actual_max_fee_per_gas,
+            max_priority_fee_per_gas: actual_max_priority_fee_per_gas,
+            ..context()
+        };
+
+        let shared = SharedGrantSettings {
+            max_gas_fee_per_gas,
+            max_priority_fee_per_gas,
+            ..shared_settings()
+        };
+        let violations = check_shared_constraints(&context, &shared, 999, &mut *conn)
+            .await
+            .unwrap();
+
+        assert_eq!(
+            violations
+                .iter()
+                .any(|violation| matches!(violation, EvalViolation::GasLimitExceeded { .. })),
+            expect_gas_limit_violation
+        );
+
+        if expect_gas_limit_violation {
+            assert_eq!(violations.len(), 1);
+        } else {
+            assert!(violations.is_empty());
+        }
+    }
+
+    #[rstest]
+    #[case::under_rate_limit(2, false)]
+    #[case::at_rate_limit(1, true)]
+    #[tokio::test]
+    async fn check_shared_constraints_enforces_rate_limit(
+        #[case] rate_limit_count: u32,
+        #[case] expect_rate_limit_violation: bool,
+    ) {
+        let db = db::create_test_pool().await;
+        let mut conn = db.get().await.unwrap();
+
+        let shared = SharedGrantSettings {
+            rate_limit: Some(TransactionRateLimit {
+                count: rate_limit_count,
+                window: Duration::hours(1),
+            }),
+            ..shared_settings()
+        };
+
+        let basic_grant = insert_basic_grant(&mut conn, &shared).await;
+
+        insert_into(evm_transaction_log::table)
+            .values(NewEvmTransactionLog {
+                grant_id: basic_grant.id,
+                wallet_access_id: WALLET_ACCESS_ID,
+                chain_id: CHAIN_ID as i32,
+                eth_value: super::utils::u256_to_bytes(U256::ZERO).to_vec(),
+                signed_at: SqliteTimestamp(Utc::now()),
+            })
+            .execute(&mut *conn)
+            .await
+            .unwrap();
+
+        let violations = check_shared_constraints(&context(), &shared, basic_grant.id, &mut *conn)
+            .await
+            .unwrap();
+
+        assert_eq!(
+            violations
+                .iter()
+                .any(|violation| matches!(violation, EvalViolation::RateLimitExceeded)),
+            expect_rate_limit_violation
+        );
+
+        if expect_rate_limit_violation {
+            assert_eq!(violations.len(), 1);
+        } else {
+            assert!(violations.is_empty());
+        }
+    }
+}

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

@@ -10,6 +10,7 @@ use diesel_async::{AsyncConnection, RunQueryDsl};
 use thiserror::Error;
 
 use crate::{
+    crypto::integrity::v1::Integrable,
     db::models::{self, EvmBasicGrant, EvmWalletAccess},
     evm::utils,
 };
@@ -55,6 +56,9 @@ pub enum EvalViolation {
 
     #[error("Transaction type is not allowed by this grant")]
     InvalidTransactionType,
+
+    #[error("Mismatching chain ID")]
+    MismatchingChainId { expected: ChainId, actual: ChainId },
 }
 
 pub type DatabaseID = i32;
@@ -62,13 +66,12 @@ pub type DatabaseID = i32;
 #[derive(Debug)]
 pub struct Grant<PolicySettings> {
     pub id: DatabaseID,
-    pub shared_grant_id: DatabaseID, // ID of the basic grant for shared-logic checks like rate limits and validity periods
-    pub shared: SharedGrantSettings,
-    pub settings: PolicySettings,
+    pub common_settings_id: DatabaseID, // ID of the basic grant for shared-logic checks like rate limits and validity periods
+    pub settings: CombinedSettings<PolicySettings>,
 }
 
 pub trait Policy: Sized {
-    type Settings: Send + Sync + 'static + Into<SpecificGrant>;
+    type Settings: Send + Sync + 'static + Into<SpecificGrant> + Integrable;
     type Meaning: Display + std::fmt::Debug + Send + Sync + 'static + Into<SpecificMeaning>;
 
     fn analyze(context: &EvalContext) -> Option<Self::Meaning>;
@@ -124,13 +127,13 @@ pub enum SpecificMeaning {
     TokenTransfer(token_transfers::Meaning),
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub struct TransactionRateLimit {
     pub count: u32,
     pub window: Duration,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub struct VolumeRateLimit {
     pub max_volume: U256,
     pub window: Duration,
@@ -151,7 +154,7 @@ pub struct SharedGrantSettings {
 }
 
 impl SharedGrantSettings {
-    fn try_from_model(model: EvmBasicGrant) -> QueryResult<Self> {
+    pub(crate) fn try_from_model(model: EvmBasicGrant) -> QueryResult<Self> {
         Ok(Self {
             wallet_access_id: model.wallet_access_id,
             chain: model.chain_id as u64, // safe because chain_id is stored as i32 but is guaranteed to be a valid ChainId by the API when creating grants
@@ -197,7 +200,57 @@ pub enum SpecificGrant {
     TokenTransfer(token_transfers::Settings),
 }
 
-pub struct FullGrant<PolicyGrant> {
-    pub basic: SharedGrantSettings,
+#[derive(Debug)]
+pub struct CombinedSettings<PolicyGrant> {
+    pub shared: SharedGrantSettings,
     pub specific: PolicyGrant,
 }
+
+impl<P> CombinedSettings<P> {
+    pub fn generalize<Y: From<P>>(self) -> CombinedSettings<Y> {
+        CombinedSettings {
+            shared: self.shared,
+            specific: self.specific.into(),
+        }
+    }
+}
+
+impl<P: Integrable> Integrable for CombinedSettings<P> {
+    const KIND: &'static str = P::KIND;
+    const VERSION: i32 = P::VERSION;
+}
+
+use crate::crypto::integrity::hashing::Hashable;
+
+impl Hashable for TransactionRateLimit {
+    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
+        self.count.hash(hasher);
+        self.window.hash(hasher);
+    }
+}
+
+impl Hashable for VolumeRateLimit {
+    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
+        self.max_volume.hash(hasher);
+        self.window.hash(hasher);
+    }
+}
+
+impl Hashable for SharedGrantSettings {
+    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
+        self.wallet_access_id.hash(hasher);
+        self.chain.hash(hasher);
+        self.valid_from.hash(hasher);
+        self.valid_until.hash(hasher);
+        self.max_gas_fee_per_gas.hash(hasher);
+        self.max_priority_fee_per_gas.hash(hasher);
+        self.rate_limit.hash(hasher);
+    }
+}
+
+impl<P: Hashable> Hashable for CombinedSettings<P> {
+    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
+        self.shared.hash(hasher);
+        self.specific.hash(hasher);
+    }
+}

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

@@ -8,13 +8,14 @@ use diesel::sqlite::Sqlite;
 use diesel::{ExpressionMethods, JoinOnDsl, prelude::*};
 use diesel_async::{AsyncConnection, RunQueryDsl};
 
+use crate::crypto::integrity::v1::Integrable;
 use crate::db::models::{
     EvmBasicGrant, EvmEtherTransferGrant, EvmEtherTransferGrantTarget, EvmEtherTransferLimit,
     NewEvmEtherTransferLimit, SqliteTimestamp,
 };
 use crate::db::schema::{evm_basic_grant, evm_ether_transfer_limit, evm_transaction_log};
 use crate::evm::policies::{
-    Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning, VolumeRateLimit,
+    CombinedSettings, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning, VolumeRateLimit,
 };
 use crate::{
     db::{
@@ -56,6 +57,18 @@ pub struct Settings {
     pub target: Vec<Address>,
     pub limit: VolumeRateLimit,
 }
+impl Integrable for Settings {
+    const KIND: &'static str = "EtherTransfer";
+}
+
+use crate::crypto::integrity::hashing::Hashable;
+
+impl Hashable for Settings {
+    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
+        self.target.hash(hasher);
+        self.limit.hash(hasher);
+    }
+}
 
 impl From<Settings> for SpecificGrant {
     fn from(val: Settings) -> SpecificGrant {
@@ -95,17 +108,17 @@ async fn check_rate_limits(
     db: &mut impl AsyncConnection<Backend = Sqlite>,
 ) -> QueryResult<Vec<EvalViolation>> {
     let mut violations = Vec::new();
-    let window = grant.settings.limit.window;
+    let window = grant.settings.specific.limit.window;
 
     let past_transaction = query_relevant_past_transaction(grant.id, window, db).await?;
 
-    let window_start = chrono::Utc::now() - grant.settings.limit.window;
+    let window_start = chrono::Utc::now() - grant.settings.specific.limit.window;
     let prospective_cumulative_volume: U256 = past_transaction
         .iter()
         .filter(|(_, timestamp)| timestamp >= &window_start)
         .fold(current_transfer_value, |acc, (value, _)| acc + *value);
 
-    if prospective_cumulative_volume > grant.settings.limit.max_volume {
+    if prospective_cumulative_volume > grant.settings.specific.limit.max_volume {
         violations.push(EvalViolation::VolumetricLimitExceeded);
     }
 
@@ -138,7 +151,7 @@ impl Policy for EtherTransfer {
         let mut violations = Vec::new();
 
         // Check if the target address is within the grant's allowed targets
-        if !grant.settings.target.contains(&meaning.to) {
+        if !grant.settings.specific.target.contains(&meaning.to) {
             violations.push(EvalViolation::InvalidTarget { target: meaning.to });
         }
 
@@ -247,9 +260,11 @@ impl Policy for EtherTransfer {
 
         Ok(Some(Grant {
             id: grant.id,
-            shared_grant_id: grant.basic_grant_id,
-            shared: SharedGrantSettings::try_from_model(basic_grant)?,
-            settings,
+            common_settings_id: grant.basic_grant_id,
+            settings: CombinedSettings {
+                shared: SharedGrantSettings::try_from_model(basic_grant)?,
+                specific: settings,
+            },
         }))
     }
 
@@ -327,15 +342,17 @@ impl Policy for EtherTransfer {
 
                 Ok(Grant {
                     id: specific.id,
-                    shared_grant_id: specific.basic_grant_id,
-                    shared: SharedGrantSettings::try_from_model(basic)?,
-                    settings: Settings {
-                        target: targets,
-                        limit: VolumeRateLimit {
-                            max_volume: utils::try_bytes_to_u256(&limit.max_volume).map_err(
-                                |e| diesel::result::Error::DeserializationError(Box::new(e)),
-                            )?,
-                            window: Duration::seconds(limit.window_secs as i64),
+                    common_settings_id: specific.basic_grant_id,
+                    settings: CombinedSettings {
+                        shared: SharedGrantSettings::try_from_model(basic)?,
+                        specific: Settings {
+                            target: targets,
+                            limit: VolumeRateLimit {
+                                max_volume: utils::try_bytes_to_u256(&limit.max_volume).map_err(
+                                    |e| diesel::result::Error::DeserializationError(Box::new(e)),
+                                )?,
+                                window: Duration::seconds(limit.window_secs as i64),
+                            },
                         },
                     },
                 })

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

@@ -11,7 +11,10 @@ use crate::db::{
     schema::{evm_basic_grant, evm_transaction_log},
 };
 use crate::evm::{
-    policies::{EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings, VolumeRateLimit},
+    policies::{
+        CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
+        VolumeRateLimit,
+    },
     utils,
 };
 
@@ -81,8 +84,6 @@ fn shared() -> SharedGrantSettings {
     }
 }
 
-// ── analyze ─────────────────────────────────────────────────────────────
-
 #[test]
 fn analyze_matches_empty_calldata() {
     let m = EtherTransfer::analyze(&ctx(ALLOWED, U256::from(1_000u64))).unwrap();
@@ -99,8 +100,6 @@ fn analyze_rejects_nonempty_calldata() {
     assert!(EtherTransfer::analyze(&context).is_none());
 }
 
-// ── evaluate ────────────────────────────────────────────────────────────
-
 #[tokio::test]
 async fn evaluate_passes_for_allowed_target() {
     let db = db::create_test_pool().await;
@@ -108,9 +107,11 @@ async fn evaluate_passes_for_allowed_target() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
-        shared: shared(),
-        settings: make_settings(vec![ALLOWED], 1_000_000),
+        common_settings_id: 999,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: make_settings(vec![ALLOWED], 1_000_000),
+        },
     };
     let context = ctx(ALLOWED, U256::from(100u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -127,9 +128,11 @@ async fn evaluate_rejects_disallowed_target() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
-        shared: shared(),
-        settings: make_settings(vec![ALLOWED], 1_000_000),
+        common_settings_id: 999,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: make_settings(vec![ALLOWED], 1_000_000),
+        },
     };
     let context = ctx(OTHER, U256::from(100u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -167,9 +170,11 @@ async fn evaluate_passes_when_volume_within_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
-        shared: shared(),
-        settings,
+        common_settings_id: basic.id,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: settings,
+        },
     };
     let context = ctx(ALLOWED, U256::from(100u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -207,9 +212,11 @@ async fn evaluate_rejects_volume_over_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
-        shared: shared(),
-        settings,
+        common_settings_id: basic.id,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: settings,
+        },
     };
     let context = ctx(ALLOWED, U256::from(1u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -248,9 +255,11 @@ async fn evaluate_passes_at_exactly_volume_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
-        shared: shared(),
-        settings,
+        common_settings_id: basic.id,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: settings,
+        },
     };
     let context = ctx(ALLOWED, U256::from(100u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -263,8 +272,6 @@ async fn evaluate_passes_at_exactly_volume_limit() {
     );
 }
 
-// ── try_find_grant ───────────────────────────────────────────────────────
-
 #[tokio::test]
 async fn try_find_grant_roundtrip() {
     let db = db::create_test_pool().await;
@@ -282,8 +289,11 @@ async fn try_find_grant_roundtrip() {
 
     assert!(found.is_some());
     let g = found.unwrap();
-    assert_eq!(g.settings.target, vec![ALLOWED]);
-    assert_eq!(g.settings.limit.max_volume, U256::from(1_000_000u64));
+    assert_eq!(g.settings.specific.target, vec![ALLOWED]);
+    assert_eq!(
+        g.settings.specific.limit.max_volume,
+        U256::from(1_000_000u64)
+    );
 }
 
 #[tokio::test]
@@ -320,7 +330,36 @@ async fn try_find_grant_wrong_target_returns_none() {
     assert!(found.is_none());
 }
 
-// ── find_all_grants ──────────────────────────────────────────────────────
+proptest::proptest! {
+    #[test]
+    fn target_order_does_not_affect_hash(
+        raw_addrs in proptest::collection::vec(proptest::prelude::any::<[u8; 20]>(), 0..8),
+        seed in proptest::prelude::any::<u64>(),
+        max_volume in proptest::prelude::any::<u64>(),
+        window_secs in 1i64..=86400,
+    ) {
+        use rand::{SeedableRng, seq::SliceRandom};
+        use sha2::Digest;
+        use crate::crypto::integrity::hashing::Hashable;
+
+        let addrs: Vec<Address> = raw_addrs.iter().map(|b| Address::from(*b)).collect();
+        let mut shuffled = addrs.clone();
+        shuffled.shuffle(&mut rand::rngs::StdRng::seed_from_u64(seed));
+
+        let limit = VolumeRateLimit {
+            max_volume: U256::from(max_volume),
+            window: Duration::seconds(window_secs),
+        };
+
+        let mut h1 = sha2::Sha256::new();
+        Settings { target: addrs, limit: limit.clone() }.hash(&mut h1);
+
+        let mut h2 = sha2::Sha256::new();
+        Settings { target: shuffled, limit }.hash(&mut h2);
+
+        proptest::prop_assert_eq!(h1.finalize(), h2.finalize());
+    }
+}
 
 #[tokio::test]
 async fn find_all_grants_empty_db() {
@@ -347,7 +386,7 @@ async fn find_all_grants_excludes_revoked() {
 
     let all = EtherTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 1);
-    assert_eq!(all[0].settings.target, vec![ALLOWED]);
+    assert_eq!(all[0].settings.specific.target, vec![ALLOWED]);
 }
 
 #[tokio::test]
@@ -363,8 +402,11 @@ async fn find_all_grants_multiple_targets() {
 
     let all = EtherTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 1);
-    assert_eq!(all[0].settings.target.len(), 2);
-    assert_eq!(all[0].settings.limit.max_volume, U256::from(1_000_000u64));
+    assert_eq!(all[0].settings.specific.target.len(), 2);
+    assert_eq!(
+        all[0].settings.specific.limit.max_volume,
+        U256::from(1_000_000u64)
+    );
 }
 
 #[tokio::test]

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

@@ -1,20 +1,5 @@
 use std::collections::HashMap;
 
-use alloy::{
-    primitives::{Address, U256},
-    sol_types::SolCall,
-};
-use arbiter_tokens_registry::evm::nonfungible::{self, TokenInfo};
-use chrono::{DateTime, Duration, Utc};
-use diesel::dsl::{auto_type, insert_into};
-use diesel::sqlite::Sqlite;
-use diesel::{ExpressionMethods, prelude::*};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-
-use crate::db::models::{
-    EvmBasicGrant, EvmTokenTransferGrant, EvmTokenTransferVolumeLimit, NewEvmTokenTransferGrant,
-    NewEvmTokenTransferLog, NewEvmTokenTransferVolumeLimit, SqliteTimestamp,
-};
 use crate::db::schema::{
     evm_basic_grant, evm_token_transfer_grant, evm_token_transfer_log,
     evm_token_transfer_volume_limit,
@@ -26,6 +11,25 @@ use crate::evm::{
     },
     utils,
 };
+use crate::{
+    crypto::integrity::Integrable,
+    db::models::{
+        EvmBasicGrant, EvmTokenTransferGrant, EvmTokenTransferVolumeLimit,
+        NewEvmTokenTransferGrant, NewEvmTokenTransferLog, NewEvmTokenTransferVolumeLimit,
+        SqliteTimestamp,
+    },
+    evm::policies::CombinedSettings,
+};
+use alloy::{
+    primitives::{Address, U256},
+    sol_types::SolCall,
+};
+use arbiter_tokens_registry::evm::nonfungible::{self, TokenInfo};
+use chrono::{DateTime, Duration, Utc};
+use diesel::dsl::{auto_type, insert_into};
+use diesel::sqlite::Sqlite;
+use diesel::{ExpressionMethods, prelude::*};
+use diesel_async::{AsyncConnection, RunQueryDsl};
 
 use super::{DatabaseID, EvalContext, EvalViolation};
 
@@ -38,9 +42,9 @@ fn grant_join() -> _ {
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Meaning {
-    pub(crate) token: &'static TokenInfo,
-    pub(crate) to: Address,
-    pub(crate) value: U256,
+    pub token: &'static TokenInfo,
+    pub to: Address,
+    pub value: U256,
 }
 impl std::fmt::Display for Meaning {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -64,6 +68,20 @@ pub struct Settings {
     pub target: Option<Address>,
     pub volume_limits: Vec<VolumeRateLimit>,
 }
+impl Integrable for Settings {
+    const KIND: &'static str = "TokenTransfer";
+}
+
+use crate::crypto::integrity::hashing::Hashable;
+
+impl Hashable for Settings {
+    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
+        self.token_contract.hash(hasher);
+        self.target.hash(hasher);
+        self.volume_limits.hash(hasher);
+    }
+}
+
 impl From<Settings> for SpecificGrant {
     fn from(val: Settings) -> SpecificGrant {
         SpecificGrant::TokenTransfer(val)
@@ -106,13 +124,20 @@ async fn check_volume_rate_limits(
 ) -> QueryResult<Vec<EvalViolation>> {
     let mut violations = Vec::new();
 
-    let Some(longest_window) = grant.settings.volume_limits.iter().map(|l| l.window).max() else {
+    let Some(longest_window) = grant
+        .settings
+        .specific
+        .volume_limits
+        .iter()
+        .map(|l| l.window)
+        .max()
+    else {
         return Ok(violations);
     };
 
     let past_transfers = query_relevant_past_transfers(grant.id, longest_window, db).await?;
 
-    for limit in &grant.settings.volume_limits {
+    for limit in &grant.settings.specific.volume_limits {
         let window_start = chrono::Utc::now() - limit.window;
         let prospective_cumulative_volume: U256 = past_transfers
             .iter()
@@ -158,7 +183,7 @@ impl Policy for TokenTransfer {
             return Ok(violations);
         }
 
-        if let Some(allowed) = grant.settings.target
+        if let Some(allowed) = grant.settings.specific.target
             && allowed != meaning.to
         {
             violations.push(EvalViolation::InvalidTarget { target: meaning.to });
@@ -269,9 +294,11 @@ impl Policy for TokenTransfer {
 
         Ok(Some(Grant {
             id: token_grant.id,
-            shared_grant_id: token_grant.basic_grant_id,
-            shared: SharedGrantSettings::try_from_model(basic_grant)?,
-            settings,
+            common_settings_id: token_grant.basic_grant_id,
+            settings: CombinedSettings {
+                shared: SharedGrantSettings::try_from_model(basic_grant)?,
+                specific: settings,
+            },
         }))
     }
 
@@ -369,12 +396,14 @@ impl Policy for TokenTransfer {
 
                 Ok(Grant {
                     id: specific.id,
-                    shared_grant_id: specific.basic_grant_id,
-                    shared: SharedGrantSettings::try_from_model(basic)?,
-                    settings: Settings {
-                        token_contract: Address::from(token_contract),
-                        target,
-                        volume_limits,
+                    common_settings_id: specific.basic_grant_id,
+                    settings: CombinedSettings {
+                        shared: SharedGrantSettings::try_from_model(basic)?,
+                        specific: Settings {
+                            token_contract: Address::from(token_contract),
+                            target,
+                            volume_limits,
+                        },
                     },
                 })
             })

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

@@ -11,7 +11,10 @@ use crate::db::{
 };
 use crate::evm::{
     abi::IERC20::transferCall,
-    policies::{EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings, VolumeRateLimit},
+    policies::{
+        CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
+        VolumeRateLimit,
+    },
     utils,
 };
 
@@ -98,8 +101,6 @@ fn shared() -> SharedGrantSettings {
     }
 }
 
-// ── analyze ─────────────────────────────────────────────────────────────
-
 #[test]
 fn analyze_known_token_valid_calldata() {
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
@@ -125,8 +126,6 @@ fn analyze_empty_calldata_returns_none() {
     assert!(TokenTransfer::analyze(&ctx(DAI, Bytes::new())).is_none());
 }
 
-// ── evaluate ────────────────────────────────────────────────────────────
-
 #[tokio::test]
 async fn evaluate_rejects_nonzero_eth_value() {
     let db = db::create_test_pool().await;
@@ -134,9 +133,11 @@ async fn evaluate_rejects_nonzero_eth_value() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
-        shared: shared(),
-        settings: make_settings(None, None),
+        common_settings_id: 999,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: make_settings(None, None),
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let mut context = ctx(DAI, calldata);
@@ -163,9 +164,11 @@ async fn evaluate_passes_any_recipient_when_no_restriction() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
-        shared: shared(),
-        settings: make_settings(None, None),
+        common_settings_id: 999,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: make_settings(None, None),
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
@@ -183,9 +186,11 @@ async fn evaluate_passes_matching_restricted_recipient() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
-        shared: shared(),
-        settings: make_settings(Some(RECIPIENT), None),
+        common_settings_id: 999,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: make_settings(Some(RECIPIENT), None),
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
@@ -203,9 +208,11 @@ async fn evaluate_rejects_wrong_restricted_recipient() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
-        shared: shared(),
-        settings: make_settings(Some(RECIPIENT), None),
+        common_settings_id: 999,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: make_settings(Some(RECIPIENT), None),
+        },
     };
     let calldata = transfer_calldata(OTHER, U256::from(100u64));
     let context = ctx(DAI, calldata);
@@ -247,9 +254,11 @@ async fn evaluate_passes_volume_at_exact_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
-        shared: shared(),
-        settings,
+        common_settings_id: basic.id,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: settings,
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
@@ -290,9 +299,11 @@ async fn evaluate_rejects_volume_over_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
-        shared: shared(),
-        settings,
+        common_settings_id: basic.id,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: settings,
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(1u64));
     let context = ctx(DAI, calldata);
@@ -313,9 +324,11 @@ async fn evaluate_no_volume_limits_always_passes() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
-        shared: shared(),
-        settings: make_settings(None, None), // no volume limits
+        common_settings_id: 999,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: make_settings(None, None), // no volume limits
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(u64::MAX));
     let context = ctx(DAI, calldata);
@@ -349,10 +362,13 @@ async fn try_find_grant_roundtrip() {
 
     assert!(found.is_some());
     let g = found.unwrap();
-    assert_eq!(g.settings.token_contract, DAI);
-    assert_eq!(g.settings.target, Some(RECIPIENT));
-    assert_eq!(g.settings.volume_limits.len(), 1);
-    assert_eq!(g.settings.volume_limits[0].max_volume, U256::from(5_000u64));
+    assert_eq!(g.settings.specific.token_contract, DAI);
+    assert_eq!(g.settings.specific.target, Some(RECIPIENT));
+    assert_eq!(g.settings.specific.volume_limits.len(), 1);
+    assert_eq!(
+        g.settings.specific.volume_limits[0].max_volume,
+        U256::from(5_000u64)
+    );
 }
 
 #[tokio::test]
@@ -392,7 +408,39 @@ async fn try_find_grant_unknown_token_returns_none() {
     assert!(found.is_none());
 }
 
-// ── find_all_grants ──────────────────────────────────────────────────────
+proptest::proptest! {
+    #[test]
+    fn volume_limits_order_does_not_affect_hash(
+        raw_limits in proptest::collection::vec(
+            (proptest::prelude::any::<u64>(), 1i64..=86400),
+            0..8,
+        ),
+        seed in proptest::prelude::any::<u64>(),
+    ) {
+        use rand::{SeedableRng, seq::SliceRandom};
+        use sha2::Digest;
+        use crate::crypto::integrity::hashing::Hashable;
+
+        let limits: Vec<VolumeRateLimit> = raw_limits
+            .iter()
+            .map(|(max_vol, window_secs)| VolumeRateLimit {
+                max_volume: U256::from(*max_vol),
+                window: Duration::seconds(*window_secs),
+            })
+            .collect();
+
+        let mut shuffled = limits.clone();
+        shuffled.shuffle(&mut rand::rngs::StdRng::seed_from_u64(seed));
+
+        let mut h1 = sha2::Sha256::new();
+        Settings { token_contract: DAI, target: None, volume_limits: limits }.hash(&mut h1);
+
+        let mut h2 = sha2::Sha256::new();
+        Settings { token_contract: DAI, target: None, volume_limits: shuffled }.hash(&mut h2);
+
+        proptest::prop_assert_eq!(h1.finalize(), h2.finalize());
+    }
+}
 
 #[tokio::test]
 async fn find_all_grants_empty_db() {
@@ -434,9 +482,9 @@ async fn find_all_grants_loads_volume_limits() {
 
     let all = TokenTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 1);
-    assert_eq!(all[0].settings.volume_limits.len(), 1);
+    assert_eq!(all[0].settings.specific.volume_limits.len(), 1);
     assert_eq!(
-        all[0].settings.volume_limits[0].max_volume,
+        all[0].settings.specific.volume_limits[0].max_volume,
         U256::from(9_999u64)
     );
 }

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

@@ -1,12 +1,12 @@
 use std::sync::Mutex;
 
-use crate::safe_cell::{SafeCell, SafeCellHandle as _};
 use alloy::{
     consensus::SignableTransaction,
     network::{TxSigner, TxSignerSync},
     primitives::{Address, B256, ChainId, Signature},
     signers::{Error, Result, Signer, SignerSync, utils::secret_key_to_address},
 };
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use async_trait::async_trait;
 use k256::ecdsa::{self, RecoveryId, SigningKey, signature::hazmat::PrehashSigner};
 

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

@@ -1,3 +1,4 @@
+use arbiter_crypto::authn;
 use arbiter_proto::{
     ClientMetadata,
     proto::{
@@ -21,8 +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> {
@@ -45,7 +46,7 @@ impl<'a> AuthTransportAdapter<'a> {
         match response {
             auth::Outbound::AuthChallenge { pubkey, nonce } => {
                 AuthResponsePayload::Challenge(ProtoAuthChallenge {
-                    pubkey: pubkey.to_bytes().to_vec(),
+                    pubkey: pubkey.to_bytes(),
                     nonce,
                 })
             }
@@ -68,6 +69,7 @@ impl<'a> AuthTransportAdapter<'a> {
                 auth::Error::ApproveError(auth::ApproveError::Internal)
                 | auth::Error::DatabasePoolUnavailable
                 | auth::Error::DatabaseOperationFailed
+                | auth::Error::IntegrityCheckFailed
                 | auth::Error::Transport => ProtoAuthResult::Internal,
             }
             .into(),
@@ -159,11 +161,7 @@ impl Receiver<auth::Inbound> for AuthTransportAdapter<'_> {
                         .await;
                     return None;
                 };
-                let Ok(pubkey) = <[u8; 32]>::try_from(pubkey) else {
-                    let _ = self.send_auth_result(ProtoAuthResult::InvalidKey).await;
-                    return None;
-                };
-                let Ok(pubkey) = ed25519_dalek::VerifyingKey::from_bytes(&pubkey) else {
+                let Ok(pubkey) = authn::PublicKey::try_from(pubkey.as_slice()) else {
                     let _ = self.send_auth_result(ProtoAuthResult::InvalidKey).await;
                     return None;
                 };
@@ -173,7 +171,7 @@ impl Receiver<auth::Inbound> for AuthTransportAdapter<'_> {
                 })
             }
             AuthRequestPayload::ChallengeSolution(ProtoAuthChallengeSolution { signature }) => {
-                let Ok(signature) = ed25519_dalek::Signature::try_from(signature.as_slice()) else {
+                let Ok(signature) = authn::Signature::try_from(signature.as_slice()) else {
                     let _ = self
                         .send_auth_result(ProtoAuthResult::InvalidSignature)
                         .await;

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/common/outbound.rs

@@ -8,7 +8,7 @@ use arbiter_proto::proto::{
         EvalViolation as ProtoEvalViolation, GasLimitExceededViolation, NoMatchingGrantError,
         PolicyViolationsError, SpecificMeaning as ProtoSpecificMeaning,
         TokenInfo as ProtoTokenInfo, TransactionEvalError as ProtoTransactionEvalError,
-        eval_violation::Kind as ProtoEvalViolationKind,
+        eval_violation as proto_eval_violation, eval_violation::Kind as ProtoEvalViolationKind,
         specific_meaning::Meaning as ProtoSpecificMeaningKind,
         transaction_eval_error::Kind as ProtoTransactionEvalErrorKind,
     },
@@ -79,6 +79,12 @@ impl Convert for EvalViolation {
             EvalViolation::InvalidTransactionType => {
                 ProtoEvalViolationKind::InvalidTransactionType(())
             }
+            EvalViolation::MismatchingChainId { expected, actual } => {
+                ProtoEvalViolationKind::ChainIdMismatch(proto_eval_violation::ChainIdMismatch {
+                    expected,
+                    actual,
+                })
+            }
         };
 
         ProtoEvalViolation { kind: Some(kind) }
@@ -108,12 +114,12 @@ impl Convert for VetError {
                         violations: violations.into_iter().map(Convert::convert).collect(),
                     })
                 }
-                PolicyError::Database(_) => {
+                PolicyError::Database(_) | PolicyError::Integrity(_) => {
                     return EvmSignTransactionResult::Error(ProtoEvmError::Internal.into());
                 }
             },
         };
 
-        EvmSignTransactionResult::EvalError(ProtoTransactionEvalError { kind: Some(kind) }.into())
+        EvmSignTransactionResult::EvalError(ProtoTransactionEvalError { kind: Some(kind) })
     }
 }

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

@@ -1,4 +1,4 @@
-use tokio::sync::mpsc;
+use tokio::sync::{mpsc, oneshot};
 
 use arbiter_proto::{
     proto::user_agent::{
@@ -14,8 +14,12 @@ use tonic::Status;
 use tracing::{error, info, warn};
 
 use crate::{
-    actors::user_agent::{OutOfBand, UserAgentConnection, UserAgentSession},
+    crypto::integrity,
     grpc::request_tracker::RequestTracker,
+    peers::user_agent::{
+        Credentials, OutOfBand, UserAgentConnection, UserAgentSession,
+        vault_gate::VaultGate,
+    },
 };
 
 mod auth;
@@ -24,6 +28,7 @@ mod inbound;
 mod outbound;
 mod sdk_client;
 mod vault;
+mod vault_gate;
 
 pub struct OutOfBandAdapter(mpsc::Sender<OutOfBand>);
 
@@ -124,21 +129,115 @@ 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,
+    let auth_creds = match auth::start(&mut conn, &mut bi, &mut request_tracker).await {
+        Ok(creds) => creds,
         Err(e) => {
             warn!(error = ?e, "Authentication failed");
             return;
         }
     };
 
+    info!(pubkey = ?auth_creds.creds.pubkey, "User authenticated successfully");
+
+    let creds = if integrity::is_signing_available(&conn.actors.vault)
+        .await
+        .unwrap_or(false)
+    {
+        // Vault is unsealed; integrity was verified during auth — promote directly.
+        auth_creds.creds
+    } else {
+        // Vault is sealed/unbootstrapped; run the VaultGate phase.
+        let (promotion_tx, promotion_rx) = oneshot::channel();
+        let gate = VaultGate::spawn(VaultGate::new(
+            auth_creds,
+            conn.actors.clone(),
+            conn.db.clone(),
+            promotion_tx,
+        ));
+
+        let result = vault_gate_loop(&mut bi, &gate, &mut request_tracker, promotion_rx).await;
+        gate.kill();
+
+        match result {
+            Some(creds) => creds,
+            None => 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 = UserAgentSession::spawn(UserAgentSession::new(conn, creds, Box::new(oob_adapter)));
     let actor_for_cleanup = actor.clone();
 
-    info!(?pubkey, "User authenticated successfully");
     dispatch_loop(bi, actor, oob_receiver, request_tracker).await;
     actor_for_cleanup.kill();
 }
+
+async fn vault_gate_loop(
+    bi: &mut GrpcBi<UserAgentRequest, UserAgentResponse>,
+    gate: &ActorRef<VaultGate>,
+    request_tracker: &mut RequestTracker,
+    mut promotion_rx: oneshot::Receiver<Result<Credentials, crate::peers::user_agent::vault_gate::Error>>,
+) -> Option<Credentials> {
+    loop {
+        tokio::select! {
+            result = &mut promotion_rx => {
+                return match result {
+                    Ok(Ok(creds)) => Some(creds),
+                    Ok(Err(e)) => {
+                        warn!(error = ?e, "VaultGate promotion failed");
+                        None
+                    }
+                    Err(_) => {
+                        warn!("VaultGate promotion channel closed unexpectedly");
+                        None
+                    }
+                };
+            }
+
+            message = bi.recv() => {
+                let Some(message) = message else { return None; };
+
+                let conn = match message {
+                    Ok(conn) => conn,
+                    Err(err) => {
+                        warn!(error = ?err, "Failed to receive request during vault gate phase");
+                        return None;
+                    }
+                };
+
+                let request_id = match request_tracker.request(conn.id) {
+                    Ok(id) => id,
+                    Err(err) => {
+                        let _ = bi.send(Err(err)).await;
+                        return None;
+                    }
+                };
+
+                let Some(payload) = conn.payload else {
+                    let _ = bi.send(Err(Status::invalid_argument("Missing request payload"))).await;
+                    return None;
+                };
+
+                let response = match payload {
+                    UserAgentRequestPayload::Vault(req) => vault_gate::dispatch(gate, req).await,
+                    _ => Err(Status::permission_denied("Only vault operations are permitted before unsealing")),
+                };
+
+                match response {
+                    Ok(Some(payload)) => {
+                        if bi.send(Ok(UserAgentResponse { id: Some(request_id), payload: Some(payload) })).await.is_err() {
+                            return None;
+                        }
+                    }
+                    Ok(None) => {}
+                    Err(status) => {
+                        let _ = bi.send(Err(status)).await;
+                        return None;
+                    }
+                }
+            }
+        }
+    }
+}

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

@@ -1,3 +1,4 @@
+use arbiter_crypto::authn;
 use arbiter_proto::{
     proto::user_agent::{
         UserAgentRequest, UserAgentResponse,
@@ -5,8 +6,7 @@ use arbiter_proto::{
             self as proto_auth, AuthChallenge as ProtoAuthChallenge,
             AuthChallengeRequest as ProtoAuthChallengeRequest,
             AuthChallengeSolution as ProtoAuthChallengeSolution, AuthResult as ProtoAuthResult,
-            KeyType as ProtoKeyType, request::Payload as AuthRequestPayload,
-            response::Payload as AuthResponsePayload,
+            request::Payload as AuthRequestPayload, response::Payload as AuthResponsePayload,
         },
         user_agent_request::Payload as UserAgentRequestPayload,
         user_agent_response::Payload as UserAgentResponsePayload,
@@ -18,14 +18,13 @@ use tonic::Status;
 use tracing::warn;
 
 use crate::{
-    actors::user_agent::{AuthPublicKey, UserAgentConnection, auth},
-    db::models::KeyType,
     grpc::request_tracker::RequestTracker,
+    peers::user_agent::{AuthCredentials, 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> {
@@ -39,19 +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]
@@ -141,28 +156,8 @@ impl Receiver<auth::Inbound> for AuthTransportAdapter<'_> {
             AuthRequestPayload::ChallengeRequest(ProtoAuthChallengeRequest {
                 pubkey,
                 bootstrap_token,
-                key_type,
             }) => {
-                let Ok(key_type) = ProtoKeyType::try_from(key_type) else {
-                    warn!(
-                        event = "received request with invalid key type",
-                        "grpc.useragent.auth_adapter"
-                    );
-                    return None;
-                };
-                let key_type = match key_type {
-                    ProtoKeyType::Ed25519 => KeyType::Ed25519,
-                    ProtoKeyType::EcdsaSecp256k1 => KeyType::EcdsaSecp256k1,
-                    ProtoKeyType::Rsa => KeyType::Rsa,
-                    ProtoKeyType::Unspecified => {
-                        warn!(
-                            event = "received request with unspecified key type",
-                            "grpc.useragent.auth_adapter"
-                        );
-                        return None;
-                    }
-                };
-                let Ok(pubkey) = AuthPublicKey::try_from((key_type, pubkey)) else {
+                let Ok(pubkey) = authn::PublicKey::try_from(pubkey.as_slice()) else {
                     warn!(
                         event = "received request with invalid public key",
                         "grpc.useragent.auth_adapter"
@@ -188,7 +183,7 @@ pub async fn start(
     conn: &mut UserAgentConnection,
     bi: &mut GrpcBi<UserAgentRequest, UserAgentResponse>,
     request_tracker: &mut RequestTracker,
-) -> Result<AuthPublicKey, auth::Error> {
-    let transport = AuthTransportAdapter::new(bi, request_tracker);
-    auth::authenticate(conn, transport).await
+) -> Result<AuthCredentials, 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::{
-        UserAgentSession,
-        session::connection::{
-            HandleEvmWalletCreate, HandleEvmWalletList, HandleGrantCreate, HandleGrantDelete,
-            HandleGrantList, HandleSignTransaction,
-            SignTransactionError as SessionSignTransactionError,
-        },
-    },
     grpc::{
         Convert, TryConvert,
         common::inbound::{RawEvmAddress, RawEvmTransaction},
     },
+    peers::user_agent::{
+        UserAgentSession,
+        session::handlers::{
+            GrantMutationError, HandleEvmWalletCreate, HandleEvmWalletList, HandleGrantCreate,
+            HandleGrantDelete, HandleGrantList, HandleSignTransaction,
+            SignTransactionError as SessionSignTransactionError,
+        },
+    },
 };
 
 fn wrap_evm_response(payload: EvmResponsePayload) -> UserAgentResponsePayload {
@@ -114,10 +114,10 @@ async fn handle_grant_list(
             grants: grants
                 .into_iter()
                 .map(|grant| GrantEntry {
-                    id: grant.id,
-                    wallet_access_id: grant.shared.wallet_access_id,
-                    shared: Some(grant.shared.convert()),
-                    specific: Some(grant.settings.convert()),
+                    id: grant.common_settings_id,
+                    wallet_access_id: grant.settings.shared.wallet_access_id,
+                    shared: Some(grant.settings.shared.convert()),
+                    specific: Some(grant.settings.specific.convert()),
                 })
                 .collect(),
         }),
@@ -148,6 +148,9 @@ async fn handle_grant_create(
 
     let result = match actor.ask(HandleGrantCreate { basic, grant }).await {
         Ok(grant_id) => EvmGrantCreateResult::GrantId(grant_id),
+        Err(kameo::error::SendError::HandlerError(GrantMutationError::VaultSealed)) => {
+            EvmGrantCreateResult::Error(ProtoEvmError::VaultSealed.into())
+        }
         Err(err) => {
             warn!(error = ?err, "Failed to create EVM grant");
             EvmGrantCreateResult::Error(ProtoEvmError::Internal.into())
@@ -171,6 +174,9 @@ async fn handle_grant_delete(
         .await
     {
         Ok(()) => EvmGrantDeleteResult::Ok(()),
+        Err(kameo::error::SendError::HandlerError(GrantMutationError::VaultSealed)) => {
+            EvmGrantDeleteResult::Error(ProtoEvmError::VaultSealed.into())
+        }
         Err(err) => {
             warn!(error = ?err, "Failed to delete EVM grant");
             EvmGrantDeleteResult::Error(ProtoEvmError::Internal.into())

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

@@ -1,3 +1,4 @@
+use arbiter_crypto::authn;
 use arbiter_proto::proto::{
     shared::ClientInfo as ProtoClientMetadata,
     user_agent::{
@@ -20,15 +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 {
@@ -41,7 +42,7 @@ pub(super) fn out_of_band_payload(oob: OutOfBand) -> UserAgentResponsePayload {
     match oob {
         OutOfBand::ClientConnectionRequest { profile } => wrap_sdk_client_response(
             SdkClientResponsePayload::ConnectionRequest(ProtoSdkClientConnectionRequest {
-                pubkey: profile.pubkey.to_bytes().to_vec(),
+                pubkey: profile.pubkey.to_bytes(),
                 info: Some(ProtoClientMetadata {
                     name: profile.metadata.name,
                     description: profile.metadata.description,
@@ -51,7 +52,7 @@ pub(super) fn out_of_band_payload(oob: OutOfBand) -> UserAgentResponsePayload {
         ),
         OutOfBand::ClientConnectionCancel { pubkey } => wrap_sdk_client_response(
             SdkClientResponsePayload::ConnectionCancel(ProtoSdkClientConnectionCancel {
-                pubkey: pubkey.to_bytes().to_vec(),
+                pubkey: pubkey.to_bytes(),
             }),
         ),
     }
@@ -89,10 +90,8 @@ async fn handle_connection_response(
     actor: &ActorRef<UserAgentSession>,
     resp: ProtoSdkClientConnectionResponse,
 ) -> Result<Option<UserAgentResponsePayload>, Status> {
-    let pubkey_bytes = <[u8; 32]>::try_from(resp.pubkey)
-        .map_err(|_| Status::invalid_argument("Invalid Ed25519 public key length"))?;
-    let pubkey = ed25519_dalek::VerifyingKey::from_bytes(&pubkey_bytes)
-        .map_err(|_| Status::invalid_argument("Invalid Ed25519 public key"))?;
+    let pubkey = authn::PublicKey::try_from(resp.pubkey.as_slice())
+        .map_err(|_| Status::invalid_argument("Invalid ML-DSA public key"))?;
 
     actor
         .ask(HandleNewClientApprove {
@@ -117,7 +116,7 @@ async fn handle_list(
                 .into_iter()
                 .map(|(client, metadata)| ProtoSdkClientEntry {
                     id: client.id,
-                    pubkey: client.public_key,
+                    pubkey: client.public_key.to_vec(),
                     info: Some(ProtoClientMetadata {
                         name: metadata.name,
                         description: metadata.description,

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 +1,238 @@
+use arbiter_proto::{
+    proto::user_agent::{
+        user_agent_request::Payload as UserAgentRequestPayload,
+        user_agent_response::Payload as UserAgentResponsePayload,
+        vault::{
+            self as proto_vault,
+            bootstrap::{self as proto_bootstrap, BootstrapResult as ProtoBootstrapResult},
+            request::Payload as VaultRequestPayload,
+            response::Payload as VaultResponsePayload,
+            unseal::{
+                self as proto_unseal, UnsealResult as ProtoUnsealResult,
+                request::Payload as UnsealRequestPayload,
+                response::Payload as UnsealResponsePayload,
+            },
+        },
+    },
+    transport::{Bi, Error as TransportError, Receiver, Sender},
+};
+use async_trait::async_trait;
+use tonic::Status;
+use tracing::warn;
+
+use super::auth::AuthTransportAdapter;
+use crate::peers::user_agent::vault_gate::{
+    self as vault_gate, HandleBootstrapEncryptedKey, HandleHandshake, HandleUnsealEncryptedKey,
+};
+
+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 AuthTransportAdapter<'_> {
+    async fn send_query_state(&mut self) -> Result<(), TransportError> {
+        use arbiter_proto::proto::shared::VaultState as ProtoVaultState;
+        self.send_response_payload(wrap_vault_response(VaultResponsePayload::State(
+            ProtoVaultState::Sealed.into(),
+        )))
+        .await
+    }
+}
+
+#[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;
+            };
+
+            let vault_req = match payload {
+                UserAgentRequestPayload::Vault(req) => req,
+                _ => {
+                    let _ = self
+                        .bi_mut()
+                        .send(Err(Status::permission_denied(
+                            "Only vault operations are permitted before unsealing",
+                        )))
+                        .await;
+                    return None;
+                }
+            };
+
+            let Some(vault_payload) = vault_req.payload else {
+                let _ = self
+                    .bi_mut()
+                    .send(Err(Status::invalid_argument("Missing vault request payload")))
+                    .await;
+                return None;
+            };
+
+            match vault_payload {
+                VaultRequestPayload::QueryState(_) => {
+                    if self.send_query_state().await.is_err() {
+                        return None;
+                    }
+                    continue;
+                }
+                VaultRequestPayload::Unseal(req) => {
+                    let Some(unseal_payload) = req.payload else {
+                        let _ = self
+                            .bi_mut()
+                            .send(Err(Status::invalid_argument("Missing unseal request payload")))
+                            .await;
+                        return None;
+                    };
+                    match unseal_payload {
+                        UnsealRequestPayload::Start(start) => {
+                            let Ok(bytes) = <[u8; 32]>::try_from(start.client_pubkey) else {
+                                let _ = self
+                                    .bi_mut()
+                                    .send(Err(Status::invalid_argument(
+                                        "Invalid X25519 public key",
+                                    )))
+                                    .await;
+                                return None;
+                            };
+                            return Some(vault_gate::Inbound::HandleHandshake(HandleHandshake {
+                                client_pubkey: x25519_dalek::PublicKey::from(bytes),
+                            }));
+                        }
+                        UnsealRequestPayload::EncryptedKey(key) => {
+                            return Some(vault_gate::Inbound::HandleUnsealEncryptedKey(
+                                HandleUnsealEncryptedKey {
+                                    nonce: key.nonce,
+                                    ciphertext: key.ciphertext,
+                                    associated_data: key.associated_data,
+                                },
+                            ));
+                        }
+                    }
+                }
+                VaultRequestPayload::Bootstrap(req) => {
+                    let Some(encrypted_key) = req.encrypted_key else {
+                        let _ = self
+                            .bi_mut()
+                            .send(Err(Status::invalid_argument(
+                                "Missing bootstrap encrypted key",
+                            )))
+                            .await;
+                        return None;
+                    };
+                    return Some(vault_gate::Inbound::HandleBootstrapEncryptedKey(
+                        HandleBootstrapEncryptedKey {
+                            nonce: encrypted_key.nonce,
+                            ciphertext: encrypted_key.ciphertext,
+                            associated_data: encrypted_key.associated_data,
+                        },
+                    ));
+                }
+            }
+        }
+    }
+}
+
+#[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;
+            }
+        };
+
+        let payload = match outbound {
+            vault_gate::Outbound::HandleHandshake(Ok(response)) => {
+                wrap_unseal_response(UnsealResponsePayload::Start(
+                    proto_unseal::UnsealStartResponse {
+                        server_pubkey: response.server_pubkey.as_bytes().to_vec(),
+                    },
+                ))
+            }
+            vault_gate::Outbound::HandleHandshake(Err(err)) => {
+                warn!(?err, "handshake failed");
+                return self
+                    .bi_mut()
+                    .send(Err(Status::internal("Failed to start unseal flow")))
+                    .await;
+            }
+            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 self
+                            .bi_mut()
+                            .send(Err(Status::internal("Failed to unseal vault")))
+                            .await;
+                    }
+                };
+                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 self
+                            .bi_mut()
+                            .send(Err(Status::internal("Failed to bootstrap vault")))
+                            .await;
+                    }
+                };
+                wrap_bootstrap_response(proto_result)
+            }
+        };
+
+        self.send_response_payload(payload).await
+    }
+}
+
+impl Bi<vault_gate::Inbound, Result<vault_gate::Outbound, vault_gate::Error>>
+    for AuthTransportAdapter<'_>
+{
+}

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

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

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

@@ -10,6 +10,7 @@ use tracing::info;
 const PORT: u16 = 50051;
 
 #[tokio::main]
+#[mutants::skip]
 async fn main() -> anyhow::Result<()> {
     aws_lc_rs::default_provider().install_default().unwrap();
 

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

@@ -1,5 +1,6 @@
+use arbiter_crypto::authn::{self, CLIENT_CONTEXT};
 use arbiter_proto::{
-    ClientMetadata, format_challenge,
+    ClientMetadata,
     transport::{Bi, expect_message},
 };
 use chrono::Utc;
@@ -8,15 +9,16 @@ use diesel::{
     dsl::insert_into, update,
 };
 use diesel_async::RunQueryDsl as _;
-use ed25519_dalek::{Signature, VerifyingKey};
-use kameo::error::SendError;
+use kameo::{actor::ActorRef, error::SendError};
 use tracing::error;
 
 use crate::{
     actors::{
-        client::{ClientConnection, ClientProfile},
+        GlobalActors,
         flow_coordinator::{self, RequestClientApproval},
+        vault::Vault,
     },
+    crypto::integrity::{self, AttestationStatus},
     db::{
         self,
         models::{ProgramClientMetadata, SqliteTimestamp},
@@ -24,12 +26,16 @@ use crate::{
     },
 };
 
+use super::{ClientConnection, ClientCredentials, ClientProfile};
+
 #[derive(thiserror::Error, Debug, Clone, PartialEq, Eq)]
 pub enum Error {
     #[error("Database pool unavailable")]
     DatabasePoolUnavailable,
     #[error("Database operation failed")]
     DatabaseOperationFailed,
+    #[error("Integrity check failed")]
+    IntegrityCheckFailed,
     #[error("Invalid challenge solution")]
     InvalidChallengeSolution,
     #[error("Client approval request failed")]
@@ -38,6 +44,13 @@ pub enum Error {
     Transport,
 }
 
+impl From<diesel::result::Error> for Error {
+    fn from(e: diesel::result::Error) -> Self {
+        error!(?e, "Database error");
+        Self::DatabaseOperationFailed
+    }
+}
+
 #[derive(thiserror::Error, Debug, Clone, PartialEq, Eq)]
 pub enum ApproveError {
     #[error("Internal error")]
@@ -51,32 +64,93 @@ pub enum ApproveError {
 #[derive(Debug, Clone)]
 pub enum Inbound {
     AuthChallengeRequest {
-        pubkey: VerifyingKey,
+        pubkey: authn::PublicKey,
         metadata: ClientMetadata,
     },
     AuthChallengeSolution {
-        signature: Signature,
+        signature: authn::Signature,
     },
 }
 
 #[derive(Debug, Clone)]
 pub enum Outbound {
-    AuthChallenge { pubkey: VerifyingKey, nonce: i32 },
+    AuthChallenge {
+        pubkey: authn::PublicKey,
+        nonce: i32,
+    },
     AuthSuccess,
 }
 
-pub struct ClientInfo {
-    pub id: i32,
-    pub current_nonce: i32,
+/// 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(
+    db: &db::DatabasePool,
+    pubkey: &authn::PublicKey,
+) -> Result<Option<(i32, i32)>, Error> {
+    let pubkey_bytes = pubkey.to_bytes();
+    let mut conn = db.get().await.map_err(|e| {
+        error!(error = ?e, "Database pool error");
+        Error::DatabasePoolUnavailable
+    })?;
+    program_client::table
+        .filter(program_client::public_key.eq(&pubkey_bytes))
+        .select((program_client::id, program_client::nonce))
+        .first::<(i32, i32)>(&mut conn)
+        .await
+        .optional()
+        .map_err(|e| {
+            error!(error = ?e, "Database error");
+            Error::DatabaseOperationFailed
+        })
 }
 
-/// Atomically reads and increments the nonce for a known client.
-/// Returns `None` if the pubkey is not registered.
-async fn get_client_and_nonce(
+async fn verify_integrity(
     db: &db::DatabasePool,
-    pubkey: &VerifyingKey,
-) -> Result<Option<ClientInfo>, Error> {
-    let pubkey_bytes = pubkey.as_bytes().to_vec();
+    vault: &ActorRef<Vault>,
+    pubkey: &authn::PublicKey,
+) -> Result<(), Error> {
+    let mut db_conn = db.get().await.map_err(|e| {
+        error!(error = ?e, "Database pool error");
+        Error::DatabasePoolUnavailable
+    })?;
+
+    let (id, nonce) = get_current_nonce_and_id(db, pubkey).await?.ok_or_else(|| {
+        error!("Client not found during integrity verification");
+        Error::DatabaseOperationFailed
+    })?;
+
+    let attestation = integrity::verify_entity(
+        &mut db_conn,
+        vault,
+        &ClientCredentials {
+            pubkey: pubkey.clone(),
+            nonce,
+        },
+        id,
+    )
+    .await
+    .map_err(|e| {
+        error!(?e, "Integrity verification failed");
+        Error::IntegrityCheckFailed
+    })?;
+
+    if attestation != AttestationStatus::Attested {
+        error!("Integrity attestation unavailable for client {id}");
+        return Err(Error::IntegrityCheckFailed);
+    }
+
+    Ok(())
+}
+
+/// 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,
+    vault: &ActorRef<Vault>,
+    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");
@@ -84,40 +158,38 @@ async fn get_client_and_nonce(
     })?;
 
     conn.exclusive_transaction(|conn| {
+        let vault = vault.clone();
+        let pubkey = pubkey.clone();
         Box::pin(async move {
-            let Some((client_id, current_nonce)) = program_client::table
+            let (id, new_nonce): (i32, i32) = update(program_client::table)
                 .filter(program_client::public_key.eq(&pubkey_bytes))
-                .select((program_client::id, program_client::nonce))
-                .first::<(i32, i32)>(conn)
-                .await
-                .optional()?
-            else {
-                return Result::<_, diesel::result::Error>::Ok(None);
-            };
-
-            update(program_client::table)
-                .filter(program_client::public_key.eq(&pubkey_bytes))
-                .set(program_client::nonce.eq(current_nonce + 1))
-                .execute(conn)
+                .set(program_client::nonce.eq(program_client::nonce + 1))
+                .returning((program_client::id, program_client::nonce))
+                .get_result(conn)
                 .await?;
 
-            Ok(Some(ClientInfo {
-                id: client_id,
-                current_nonce,
-            }))
+            integrity::sign_entity(
+                conn,
+                &vault,
+                &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
-    .map_err(|e| {
-        error!(error = ?e, "Database error");
-        Error::DatabaseOperationFailed
-    })
 }
 
-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 })
@@ -139,45 +211,65 @@ async fn approve_new_client(
 
 async fn insert_client(
     db: &db::DatabasePool,
-    pubkey: &VerifyingKey,
+    vault: &ActorRef<Vault>,
+    pubkey: &authn::PublicKey,
     metadata: &ClientMetadata,
 ) -> Result<i32, Error> {
     use crate::db::schema::{client_metadata, program_client};
+    let pubkey = pubkey.clone();
+    let metadata = metadata.clone();
+
     let mut conn = db.get().await.map_err(|e| {
         error!(error = ?e, "Database pool error");
         Error::DatabasePoolUnavailable
     })?;
 
-    let metadata_id = insert_into(client_metadata::table)
-        .values((
-            client_metadata::name.eq(&metadata.name),
-            client_metadata::description.eq(&metadata.description),
-            client_metadata::version.eq(&metadata.version),
-        ))
-        .returning(client_metadata::id)
-        .get_result::<i32>(&mut conn)
-        .await
-        .map_err(|e| {
-            error!(error = ?e, "Failed to insert client metadata");
-            Error::DatabaseOperationFailed
-        })?;
+    conn.exclusive_transaction(|conn| {
+        let vault = vault.clone();
+        let pubkey = pubkey.clone();
+        Box::pin(async move {
+            const NONCE_START: i32 = 1;
 
-    let client_id = insert_into(program_client::table)
-        .values((
-            program_client::public_key.eq(pubkey.as_bytes().to_vec()),
-            program_client::metadata_id.eq(metadata_id),
-            program_client::nonce.eq(1), // pre-incremented; challenge uses 0
-        ))
-        .on_conflict_do_nothing()
-        .returning(program_client::id)
-        .get_result::<i32>(&mut conn)
-        .await
-        .map_err(|e| {
-            error!(error = ?e, "Failed to insert client metadata");
-            Error::DatabaseOperationFailed
-        })?;
+            let metadata_id = insert_into(client_metadata::table)
+                .values((
+                    client_metadata::name.eq(&metadata.name),
+                    client_metadata::description.eq(&metadata.description),
+                    client_metadata::version.eq(&metadata.version),
+                ))
+                .returning(client_metadata::id)
+                .get_result::<i32>(conn)
+                .await?;
 
-    Ok(client_id)
+            let client_id = insert_into(program_client::table)
+                .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)
+                .get_result::<i32>(conn)
+                .await?;
+
+            integrity::sign_entity(
+                conn,
+                &vault,
+                &ClientCredentials {
+                    pubkey: pubkey.clone(),
+                    nonce: NONCE_START,
+                },
+                client_id,
+            )
+            .await
+            .map_err(|e| {
+                error!(error = ?e, "Failed to sign integrity tag for new client key");
+                Error::DatabaseOperationFailed
+            })?;
+
+            Ok(client_id)
+        })
+    })
+    .await
 }
 
 async fn sync_client_metadata(
@@ -253,14 +345,17 @@ async fn sync_client_metadata(
 
 async fn challenge_client<T>(
     transport: &mut T,
-    pubkey: VerifyingKey,
+    pubkey: authn::PublicKey,
     nonce: i32,
 ) -> Result<(), Error>
 where
     T: Bi<Inbound, Result<Outbound, Error>> + ?Sized,
 {
     transport
-        .send(Ok(Outbound::AuthChallenge { pubkey, nonce }))
+        .send(Ok(Outbound::AuthChallenge {
+            pubkey: pubkey.clone(),
+            nonce,
+        }))
         .await
         .map_err(|e| {
             error!(error = ?e, "Failed to send auth challenge");
@@ -277,12 +372,10 @@ where
         Error::Transport
     })?;
 
-    let formatted = format_challenge(nonce, pubkey.as_bytes());
-
-    pubkey.verify_strict(&formatted, &signature).map_err(|_| {
+    if !pubkey.verify(nonce, CLIENT_CONTEXT, &signature) {
         error!("Challenge solution verification failed");
-        Error::InvalidChallengeSolution
-    })?;
+        return Err(Error::InvalidChallengeSolution);
+    }
 
     Ok(())
 }
@@ -295,27 +388,27 @@ where
         return Err(Error::Transport);
     };
 
-    let info = match get_client_and_nonce(&props.db, &pubkey).await? {
-        Some(nonce) => nonce,
+    let client_id = match get_current_nonce_and_id(&props.db, &pubkey).await? {
+        Some((id, _)) => {
+            verify_integrity(&props.db, &props.actors.vault, &pubkey).await?;
+            id
+        }
         None => {
             approve_new_client(
                 &props.actors,
                 ClientProfile {
-                    pubkey,
+                    pubkey: pubkey.clone(),
                     metadata: metadata.clone(),
                 },
             )
             .await?;
-            let client_id = insert_client(&props.db, &pubkey, &metadata).await?;
-            ClientInfo {
-                id: client_id,
-                current_nonce: 0,
-            }
+            insert_client(&props.db, &props.actors.vault, &pubkey, &metadata).await?
         }
     };
 
-    sync_client_metadata(&props.db, info.id, &metadata).await?;
-    challenge_client(transport, pubkey, info.current_nonce).await?;
+    sync_client_metadata(&props.db, client_id, &metadata).await?;
+    let challenge_nonce = create_nonce(&props.db, &props.actors.vault, &pubkey).await?;
+    challenge_client(transport, pubkey, challenge_nonce).await?;
 
     transport
         .send(Ok(Outbound::AuthSuccess))
@@ -325,5 +418,5 @@ where
             Error::Transport
         })?;
 
-    Ok(info.id)
+    Ok(client_id)
 }

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

@@ -1,18 +1,37 @@
+use arbiter_crypto::authn;
 use arbiter_proto::{ClientMetadata, transport::Bi};
 use kameo::actor::Spawn;
 use tracing::{error, info};
 
 use crate::{
-    actors::{GlobalActors, client::session::ClientSession},
+    actors::GlobalActors,
+    crypto::integrity::{Integrable, hashing::Hashable},
     db,
+    peers::client::session::ClientSession,
 };
 
 #[derive(Debug, Clone)]
 pub struct ClientProfile {
-    pub pubkey: ed25519_dalek::VerifyingKey,
+    pub pubkey: authn::PublicKey,
     pub metadata: ClientMetadata,
 }
 
+pub struct ClientCredentials {
+    pub pubkey: authn::PublicKey,
+    pub nonce: i32,
+}
+
+impl Integrable for ClientCredentials {
+    const KIND: &'static str = "client_credentials";
+}
+
+impl Hashable for ClientCredentials {
+    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
+        hasher.update(self.pubkey.to_bytes());
+        self.nonce.hash(hasher);
+    }
+}
+
 pub struct ClientConnection {
     pub(crate) db: db::DatabasePool,
     pub(crate) actors: GlobalActors,
@@ -31,7 +50,9 @@ pub async fn connect_client<T>(mut props: ClientConnection, transport: &mut T)
 where
     T: Bi<auth::Inbound, Result<auth::Outbound, auth::Error>> + Send + ?Sized,
 {
-    match auth::authenticate(&mut props, transport).await {
+    let fut = auth::authenticate(&mut props, transport);
+    println!("authenticate future size: {}", std::mem::size_of_val(&fut));
+    match fut.await {
         Ok(client_id) => {
             ClientSession::spawn(ClientSession::new(props, client_id));
             info!("Client authenticated, session started");

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

@@ -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

@@ -1,18 +1,16 @@
+use arbiter_crypto::authn;
 use arbiter_proto::transport::Bi;
 use tracing::error;
 
-use crate::actors::user_agent::{
-    AuthPublicKey, UserAgentConnection,
-    auth::state::{AuthContext, AuthStateMachine},
-};
-
 mod state;
 use state::*;
 
+use super::{AuthCredentials, UserAgentConnection};
+
 #[derive(Debug, Clone)]
 pub enum Inbound {
     AuthChallengeRequest {
-        pubkey: AuthPublicKey,
+        pubkey: authn::PublicKey,
         bootstrap_token: Option<String>,
     },
     AuthChallengeSolution {
@@ -37,6 +35,13 @@ impl Error {
     }
 }
 
+impl From<diesel::result::Error> for Error {
+    fn from(e: diesel::result::Error) -> Self {
+        error!(?e, "Database error");
+        Self::internal("Database error")
+    }
+}
+
 #[derive(Debug, Clone)]
 pub enum Outbound {
     AuthChallenge { nonce: i32 },
@@ -63,10 +68,10 @@ fn parse_auth_event(payload: Inbound) -> AuthEvents {
 
 pub async fn authenticate<T>(
     props: &mut UserAgentConnection,
-    transport: T,
-) -> Result<AuthPublicKey, Error>
+    transport: &mut T,
+) -> Result<AuthCredentials, 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));
 
@@ -77,7 +82,7 @@ where
         };
 
         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 +1,329 @@
+use super::super::{AuthCredentials, Credentials, UserAgentConnection};
+use arbiter_crypto::authn::{self, USERAGENT_CONTEXT};
+use arbiter_proto::transport::Bi;
+use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl, sqlite::Sqlite, update};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use kameo::actor::ActorRef;
+use tracing::error;
+
+use super::Error;
+use crate::peers::user_agent::auth::Outbound;
+use crate::{
+    actors::{bootstrap::ConsumeToken, vault::Vault},
+    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 id: i32,
+    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(AuthCredentials),
+        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) / async verify_solution = AuthOk(AuthCredentials),
+    }
+);
+
+const NONCE_START: i32 = 1;
+
+/// 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,
+    vault: &ActorRef<Vault>,
+    pubkey: &authn::PublicKey,
+) -> Result<(), Error> {
+    let mut db_conn = db.get().await.map_err(|e| {
+        error!(error = ?e, "Database pool error");
+        Error::internal("Database unavailable")
+    })?;
+
+    let (id, nonce) = get_current_nonce_and_id(db, pubkey).await?;
+
+    let _result = integrity::verify_entity(
+        &mut db_conn,
+        vault,
+        &AuthCredentials {
+            creds: Credentials {
+                id,
+                pubkey: pubkey.clone(),
+            },
+            new_nonce: nonce,
+        },
+        id,
+    )
+    .await
+    .map_err(|e| {
+        error!(?e, "Integrity verification failed");
+        Error::internal("Integrity verification failed")
+    })?;
+
+    Ok(())
+}
+
+async fn compute_current_nonce(
+    conn: &mut impl AsyncConnection<Backend = Sqlite>,
+    pubkey: &authn::PublicKey,
+) -> Result<(i32, i32), Error> {
+    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 incrementing nonce");
+            Error::internal("Database operation failed")
+        })
+}
+
+async fn resign_credentials(
+    conn: &mut impl AsyncConnection<Backend = Sqlite>,
+    vault: &ActorRef<Vault>,
+    id: i32,
+    pubkey: &authn::PublicKey,
+    new_nonce: i32,
+) -> Result<(), Error> {
+    integrity::sign_entity(
+        conn,
+        vault,
+        &AuthCredentials {
+            creds: Credentials {
+                id,
+                pubkey: pubkey.clone(),
+            },
+            new_nonce,
+        },
+        id,
+    )
+    .await
+    .map_err(|e| {
+        error!(?e, "Integrity signature update failed");
+        Error::internal("Database error")
+    })
+}
+
+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),
+            useragent_client::nonce.eq(NONCE_START),
+        ))
+        .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 }: ChallengeRequest,
+    ) -> Result<ChallengeContext, Self::Error> {
+        let is_signing = integrity::is_signing_available(&self.conn.actors.vault)
+            .await
+            .unwrap_or(false);
+
+        if is_signing {
+            verify_integrity(&self.conn.db, &self.conn.actors.vault, &pubkey).await?;
+        }
+
+        let vault = self.conn.actors.vault.clone();
+        let mut conn = self.conn.db.get().await.map_err(|e| {
+            error!(error = ?e, "Database pool error");
+            Error::internal("Database unavailable")
+        })?;
+
+        let (id, nonce) = conn
+            .exclusive_transaction(|conn| {
+                let pubkey = pubkey.clone();
+                let vault = vault.clone();
+                Box::pin(async move {
+                    let (id, new_nonce) = compute_current_nonce(conn, &pubkey).await?;
+                    if is_signing {
+                        resign_credentials(conn, &vault, id, &pubkey, new_nonce).await?;
+                    }
+                    Result::<_, Error>::Ok((id, new_nonce))
+                })
+            })
+            .await?;
+
+        self.transport
+            .send(Ok(Outbound::AuthChallenge { nonce }))
+            .await
+            .map_err(|e| {
+                error!(?e, "Failed to send auth challenge");
+                Error::Transport
+            })?;
+
+        Ok(ChallengeContext {
+            id,
+            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<AuthCredentials, 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 => {
+                let id = register_key(&self.conn.db, &pubkey).await?;
+                self.transport
+                    .send(Ok(Outbound::AuthSuccess))
+                    .await
+                    .map_err(|_| Error::Transport)?;
+                Ok(AuthCredentials {
+                    creds: Credentials { id, pubkey },
+                    new_nonce: NONCE_START,
+                })
+            }
+            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 {
+            id,
+            challenge_nonce,
+            key,
+        }: &ChallengeContext,
+        ChallengeSolution { solution }: ChallengeSolution,
+    ) -> Result<AuthCredentials, 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(AuthCredentials {
+                    creds: Credentials {
+                        id: *id,
+                        pubkey: key.clone(),
+                    },
+                    new_nonce: *challenge_nonce,
+                })
+            }
+            false => {
+                self.transport
+                    .send(Err(Error::InvalidChallengeSolution))
+                    .await
+                    .map_err(|_| Error::Transport)?;
+                Err(Error::InvalidChallengeSolution)
+            }
+        }
+    }
+}

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

@@ -0,0 +1,175 @@
+use crate::{
+    actors::GlobalActors,
+    crypto::integrity::{self, Integrable},
+    db,
+    peers::client::ClientProfile,
+};
+use arbiter_crypto::authn;
+
+use arbiter_proto::transport::{Bi, Sender};
+pub use auth::authenticate;
+use kameo::actor::{ActorRef, Spawn as _};
+pub use session::UserAgentSession;
+use tokio::sync::oneshot;
+use tracing::warn;
+use vault_gate::VaultGate;
+
+use crate::crypto::integrity::hashing::Hashable;
+
+pub mod auth;
+pub mod session;
+pub mod vault_gate;
+
+#[derive(Debug, Clone, Hash)]
+pub struct Credentials {
+    pub id: i32,
+    pub pubkey: authn::PublicKey,
+}
+impl Hashable for Credentials {
+    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
+        self.id.hash(hasher);
+        self.pubkey.hash(hasher);
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct AuthCredentials {
+    pub creds: Credentials,
+    // denotes new nonce, not current
+    pub new_nonce: i32,
+}
+
+impl Hashable for authn::PublicKey {
+    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
+        hasher.update(self.to_bytes());
+    }
+}
+
+impl Hashable for AuthCredentials {
+    fn hash<H: sha2::Digest>(&self, hasher: &mut H) {
+        self.creds.hash(hasher);
+        self.new_nonce.hash(hasher);
+    }
+}
+
+impl Integrable for AuthCredentials {
+    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("internal: {0}")]
+    Internal(String),
+}
+
+impl From<auth::Error> for Error {
+    fn from(err: auth::Error) -> Self {
+        Self::Auth(err)
+    }
+}
+
+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 auth_creds = authenticate(props, &mut transport).await?;
+
+    let creds = if integrity::is_signing_available(&props.actors.vault)
+        .await
+        .unwrap_or(false)
+    {
+        auth_creds.creds
+    } else {
+        run_vault_gate(props, &mut transport, auth_creds).await?
+    };
+
+    Ok(UserAgentSession::spawn(UserAgentSession::new(
+        props.clone(),
+        creds,
+        oob_sender,
+    )))
+}
+
+async fn run_vault_gate<T>(
+    props: &UserAgentConnection,
+    transport: &mut T,
+    auth_creds: AuthCredentials,
+) -> Result<Credentials, 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
+}

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

@@ -0,0 +1,299 @@
+use std::sync::Mutex;
+
+use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
+use arbiter_crypto::{
+    authn,
+    safecell::{SafeCell, SafeCellHandle as _},
+};
+use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
+use diesel::{ExpressionMethods as _, QueryDsl as _, SelectableHelper};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use kameo::error::SendError;
+use kameo::messages;
+use kameo::prelude::Context;
+use tracing::{error, info};
+use x25519_dalek::{EphemeralSecret, PublicKey};
+
+use crate::actors::flow_coordinator::client_connect_approval::ClientApprovalAnswer;
+use crate::actors::{
+    evm::{
+        ClientSignTransaction, Generate, ListWallets, SignTransactionError as EvmSignError,
+        UseragentCreateGrant, UseragentListGrants,
+    },
+    vault::{self, Bootstrap, TryUnseal},
+};
+use crate::db::models::{
+    EvmWalletAccess, NewEvmWalletAccess, ProgramClient, ProgramClientMetadata,
+};
+use crate::evm::policies::{Grant, SpecificGrant};
+use crate::{
+    actors::vault::VaultState,
+};
+
+use super::{Error, UserAgentSession};
+
+
+#[derive(Debug, Error)]
+pub enum SignTransactionError {
+    #[error("Policy evaluation failed")]
+    Vet(#[from] crate::evm::VetError),
+
+    #[error("Internal signing error")]
+    Internal,
+}
+
+#[derive(Debug, Error)]
+pub enum GrantMutationError {
+    #[error("Vault is sealed")]
+    VaultSealed,
+
+    #[error("Internal grant mutation error")]
+    Internal,
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message]
+    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<VaultState, Error> {
+        use crate::actors::vault::GetState;
+
+        let vault_state = match self.props.actors.vault.ask(GetState {}).await {
+            Ok(state) => state,
+            Err(err) => {
+                error!(?err, actor = "useragent", "vault.query.failed");
+                return Err(Error::internal("Vault is in broken state"));
+            }
+        };
+
+        Ok(vault_state)
+    }
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message]
+    pub(crate) async fn handle_evm_wallet_create(&mut self) -> Result<(i32, Address), Error> {
+        match self.props.actors.evm.ask(Generate {}).await {
+            Ok(address) => Ok(address),
+            Err(SendError::HandlerError(err)) => Err(Error::internal(format!(
+                "EVM wallet generation failed: {err}"
+            ))),
+            Err(err) => {
+                error!(?err, "EVM actor unreachable during wallet create");
+                Err(Error::internal("EVM actor unreachable"))
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_evm_wallet_list(&mut self) -> Result<Vec<(i32, Address)>, Error> {
+        match self.props.actors.evm.ask(ListWallets {}).await {
+            Ok(wallets) => Ok(wallets),
+            Err(err) => {
+                error!(?err, "EVM wallet list failed");
+                Err(Error::internal("Failed to list EVM wallets"))
+            }
+        }
+    }
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message]
+    pub(crate) async fn handle_grant_list(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
+        match self.props.actors.evm.ask(UseragentListGrants {}).await {
+            Ok(grants) => Ok(grants),
+            Err(err) => {
+                error!(?err, "EVM grant list failed");
+                Err(Error::internal("Failed to list EVM grants"))
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_grant_create(
+        &mut self,
+        basic: crate::evm::policies::SharedGrantSettings,
+        grant: crate::evm::policies::SpecificGrant,
+    ) -> Result<i32, GrantMutationError> {
+        match self
+            .props
+            .actors
+            .evm
+            .ask(UseragentCreateGrant { basic, grant })
+            .await
+        {
+            Ok(grant_id) => Ok(grant_id),
+            Err(err) => {
+                error!(?err, "EVM grant create failed");
+                Err(GrantMutationError::Internal)
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_grant_delete(
+        &mut self,
+        grant_id: i32,
+    ) -> Result<(), GrantMutationError> {
+        // match self
+        //     .props
+        //     .actors
+        //     .evm
+        //     .ask(UseragentDeleteGrant { grant_id })
+        //     .await
+        // {
+        //     Ok(()) => Ok(()),
+        //     Err(err) => {
+        //         error!(?err, "EVM grant delete failed");
+        //         Err(GrantMutationError::Internal)
+        //     }
+        // }
+        let _ = grant_id;
+        todo!()
+    }
+
+    #[message]
+    pub(crate) async fn handle_sign_transaction(
+        &mut self,
+        client_id: i32,
+        wallet_address: Address,
+        transaction: TxEip1559,
+    ) -> Result<Signature, SignTransactionError> {
+        match self
+            .props
+            .actors
+            .evm
+            .ask(ClientSignTransaction {
+                client_id,
+                wallet_address,
+                transaction,
+            })
+            .await
+        {
+            Ok(signature) => Ok(signature),
+            Err(SendError::HandlerError(EvmSignError::Vet(vet_error))) => {
+                Err(SignTransactionError::Vet(vet_error))
+            }
+            Err(err) => {
+                error!(?err, "EVM sign transaction failed in user-agent session");
+                Err(SignTransactionError::Internal)
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_grant_evm_wallet_access(
+        &mut self,
+        entries: Vec<NewEvmWalletAccess>,
+    ) -> Result<(), Error> {
+        let mut conn = self.props.db.get().await?;
+        conn.transaction(|conn| {
+            Box::pin(async move {
+                use crate::db::schema::evm_wallet_access;
+
+                for entry in entries {
+                    diesel::insert_into(evm_wallet_access::table)
+                        .values(&entry)
+                        .on_conflict_do_nothing()
+                        .execute(conn)
+                        .await?;
+                }
+
+                Result::<_, Error>::Ok(())
+            })
+        })
+        .await?;
+        Ok(())
+    }
+
+    #[message]
+    pub(crate) async fn handle_revoke_evm_wallet_access(
+        &mut self,
+        entries: Vec<i32>,
+    ) -> Result<(), Error> {
+        let mut conn = self.props.db.get().await?;
+        conn.transaction(|conn| {
+            Box::pin(async move {
+                use crate::db::schema::evm_wallet_access;
+                for entry in entries {
+                    diesel::delete(evm_wallet_access::table)
+                        .filter(evm_wallet_access::wallet_id.eq(entry))
+                        .execute(conn)
+                        .await?;
+                }
+
+                Result::<_, Error>::Ok(())
+            })
+        })
+        .await?;
+        Ok(())
+    }
+
+    #[message]
+    pub(crate) async fn handle_list_wallet_access(
+        &mut self,
+    ) -> Result<Vec<EvmWalletAccess>, Error> {
+        let mut conn = self.props.db.get().await?;
+        use crate::db::schema::evm_wallet_access;
+        let access_entries = evm_wallet_access::table
+            .select(EvmWalletAccess::as_select())
+            .load::<_>(&mut conn)
+            .await?;
+        Ok(access_entries)
+    }
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message(ctx)]
+    pub(crate) async fn handle_new_client_approve(
+        &mut self,
+        approved: bool,
+        pubkey: authn::PublicKey,
+        ctx: &mut Context<Self, Result<(), Error>>,
+    ) -> Result<(), Error> {
+        let pending_approval = match self.pending_client_approvals.remove(&pubkey.to_bytes()) {
+            Some(approval) => approval,
+            None => {
+                error!("Received client connection response for unknown client");
+                return Err(Error::internal("Unknown client in connection response"));
+            }
+        };
+
+        pending_approval
+            .controller
+            .tell(ClientApprovalAnswer { approved })
+            .await
+            .map_err(|err| {
+                error!(
+                    ?err,
+                    "Failed to send client approval response to controller"
+                );
+                Error::internal("Failed to send client approval response to controller")
+            })?;
+
+        ctx.actor_ref().unlink(&pending_approval.controller).await;
+
+        Ok(())
+    }
+
+    #[message]
+    pub(crate) async fn handle_sdk_client_list(
+        &mut self,
+    ) -> Result<Vec<(ProgramClient, ProgramClientMetadata)>, Error> {
+        use crate::db::schema::{client_metadata, program_client};
+        let mut conn = self.props.db.get().await?;
+
+        let clients = program_client::table
+            .inner_join(client_metadata::table)
+            .select((
+                ProgramClient::as_select(),
+                ProgramClientMetadata::as_select(),
+            ))
+            .load::<(ProgramClient, ProgramClientMetadata)>(&mut conn)
+            .await?;
+
+        Ok(clients)
+    }
+}

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

@@ -1,20 +1,23 @@
+use arbiter_crypto::authn;
+use diesel::{ExpressionMethods, QueryDsl};
+use diesel_async::{RunQueryDsl};
+use kameo_actors::message_bus::Register;
+
 use std::{borrow::Cow, collections::HashMap};
 
 use arbiter_proto::transport::Sender;
-use async_trait::async_trait;
-use ed25519_dalek::VerifyingKey;
-use kameo::{Actor, actor::ActorRef, messages};
+use kameo::{Actor, actor::ActorRef, messages, prelude::Message};
 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::{RegisterUserAgent, client_connect_approval::ClientApprovalController},
+        vault::events,
+    }, crypto::integrity, db::schema::useragent_client, peers::{client::ClientProfile, user_agent::{AuthCredentials, Credentials}}
 };
 
-mod state;
-use state::{DummyContext, UserAgentEvents, UserAgentStateMachine};
+use super::{OutOfBand, UserAgentConnection};
 
 #[derive(Debug, Error)]
 pub enum Error {
@@ -47,52 +50,33 @@ impl Error {
 }
 
 pub struct PendingClientApproval {
+    pubkey: authn::PublicKey,
     controller: ActorRef<ClientApprovalController>,
 }
 
 pub struct UserAgentSession {
+    creds: Credentials,
     props: UserAgentConnection,
-    state: UserAgentStateMachine<DummyContext>,
     sender: Box<dyn Sender<OutOfBand>>,
 
-    pending_client_approvals: HashMap<VerifyingKey, PendingClientApproval>,
+    pending_client_approvals: HashMap<Vec<u8>, PendingClientApproval>,
 }
 
-pub mod connection;
+pub mod handlers;
 
 impl UserAgentSession {
-    pub(crate) fn new(props: UserAgentConnection, sender: Box<dyn Sender<OutOfBand>>) -> Self {
+    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]
@@ -118,8 +102,13 @@ impl UserAgentSession {
             return;
         }
 
-        self.pending_client_approvals
-            .insert(client.pubkey, PendingClientApproval { controller });
+        self.pending_client_approvals.insert(
+            client.pubkey.to_bytes(),
+            PendingClientApproval {
+                pubkey: client.pubkey,
+                controller,
+            },
+        );
     }
 }
 
@@ -158,14 +147,18 @@ impl Actor for UserAgentSession {
         let cancelled_pubkey = self
             .pending_client_approvals
             .iter()
-            .find_map(|(k, v)| (v.controller.id() == id).then_some(*k));
+            .find_map(|(k, v)| (v.controller.id() == id).then_some(k.clone()));
 
-        if let Some(pubkey) = cancelled_pubkey {
-            self.pending_client_approvals.remove(&pubkey);
+        if let Some(pubkey_bytes) = cancelled_pubkey {
+            let Some(approval) = self.pending_client_approvals.remove(&pubkey_bytes) else {
+                return Ok(std::ops::ControlFlow::Continue(()));
+            };
 
             if let Err(e) = self
                 .sender
-                .send(OutOfBand::ClientConnectionCancel { pubkey })
+                .send(OutOfBand::ClientConnectionCancel {
+                    pubkey: approval.pubkey,
+                })
                 .await
             {
                 error!(

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

@@ -0,0 +1,295 @@
+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::{AuthCredentials, Credentials};
+use crate::{
+    actors::{
+        GlobalActors,
+        vault::{self, Bootstrap, TryUnseal, events},
+    },
+    crypto::integrity::{self, AttestationStatus},
+    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: AuthCredentials,
+    pub promotion_tx: Option<oneshot::Sender<Result<Credentials, Error>>>,
+    pub state: State,
+    pub actors: GlobalActors,
+    pub db: DatabasePool,
+}
+
+impl VaultGate {
+    pub fn new(
+        auth_creds: AuthCredentials,
+        actors: GlobalActors,
+        db: DatabasePool,
+        promotion_tx: oneshot::Sender<Result<Credentials, 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"))
+            }
+        }
+    }
+}
+
+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.creds.id)
+                .await
+                .map_err(|e| {
+                    error!(?e, "Failed to sign integrity envelope on bootstrap");
+                    Error::internal("Integrity sign failed")
+                })?;
+            Ok(self.auth_creds.creds.clone())
+        }
+        .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 {
+        let result = async {
+            let mut conn = self.db.get().await.map_err(|_| Error::internal("DB unavailable"))?;
+            match integrity::verify_entity(
+                &mut conn,
+                &self.actors.vault,
+                &self.auth_creds,
+                self.auth_creds.creds.id,
+            )
+            .await
+            {
+                Ok(AttestationStatus::Attested) => Ok(self.auth_creds.creds.clone()),
+                Ok(AttestationStatus::Unavailable) => {
+                    Err(Error::internal("Vault sealed during promotion"))
+                }
+                Err(e) => {
+                    error!(?e, "Integrity verification failed during unseal promotion");
+                    Err(Error::InvalidKey)
+                }
+            }
+        }
+        .await;
+
+        if let Some(tx) = self.promotion_tx.take() {
+            let _ = tx.send(result);
+        }
+        ctx.stop();
+    }
+}

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

@@ -0,0 +1,17 @@
+use std::sync::Mutex;
+
+use x25519_dalek::{EphemeralSecret, PublicKey, SharedSecret};
+
+pub struct Handshake {
+    client_pubkey: PublicKey,
+}
+
+#[derive(Default)]
+pub enum State {
+    #[default]
+    Idle,
+    ReadyForExchange {
+        server_key: PublicKey,
+        secret: SharedSecret,
+    },
+}

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

@@ -1,13 +1,18 @@
+use arbiter_crypto::{
+    authn::{self, CLIENT_CONTEXT, format_challenge},
+    safecell::{SafeCell, SafeCellHandle as _},
+};
 use arbiter_proto::ClientMetadata;
 use arbiter_proto::transport::{Receiver, Sender};
-use arbiter_server::actors::GlobalActors;
 use arbiter_server::{
-    actors::client::{ClientConnection, auth, connect_client},
-    db,
+    actors::{GlobalActors, vault::Bootstrap},
+    crypto::integrity,
+    db::{self, schema},
+    peers::client::{ClientConnection, ClientCredentials, auth, connect_client},
 };
 use diesel::{ExpressionMethods as _, NullableExpressionMethods as _, QueryDsl as _, insert_into};
 use diesel_async::RunQueryDsl;
-use ed25519_dalek::Signer as _;
+use ml_dsa::{KeyGen, MlDsa87, SigningKey, VerifyingKey, signature::Keypair as _};
 
 use super::common::ChannelTransport;
 
@@ -21,7 +26,8 @@ fn metadata(name: &str, description: Option<&str>, version: Option<&str>) -> Cli
 
 async fn insert_registered_client(
     db: &db::DatabasePool,
-    pubkey: Vec<u8>,
+    actors: &GlobalActors,
+    pubkey: VerifyingKey<MlDsa87>,
     metadata: &ClientMetadata,
 ) {
     use arbiter_server::db::schema::{client_metadata, program_client};
@@ -37,34 +43,90 @@ async fn insert_registered_client(
         .get_result(&mut conn)
         .await
         .unwrap();
-    insert_into(program_client::table)
+    let client_id: i32 = insert_into(program_client::table)
         .values((
-            program_client::public_key.eq(pubkey),
+            program_client::public_key.eq(pubkey.encode().to_vec()),
             program_client::metadata_id.eq(metadata_id),
         ))
+        .returning(program_client::id)
+        .get_result(&mut conn)
+        .await
+        .unwrap();
+
+    integrity::sign_entity(
+        &mut conn,
+        &actors.vault,
+        &ClientCredentials {
+            pubkey: pubkey.into(),
+            nonce: 1,
+        },
+        client_id,
+    )
+    .await
+    .unwrap();
+}
+
+fn sign_client_challenge(
+    key: &SigningKey<MlDsa87>,
+    nonce: i32,
+    pubkey: &authn::PublicKey,
+) -> authn::Signature {
+    let challenge = format_challenge(nonce, &pubkey.to_bytes());
+    key.signing_key()
+        .sign_deterministic(&challenge, CLIENT_CONTEXT)
+        .unwrap()
+        .into()
+}
+
+async fn insert_bootstrap_sentinel_useragent(db: &db::DatabasePool) {
+    let mut conn = db.get().await.unwrap();
+    let sentinel_key = MlDsa87::key_gen(&mut rand::rng())
+        .verifying_key()
+        .encode()
+        .to_vec();
+
+    insert_into(schema::useragent_client::table)
+        .values((
+            schema::useragent_client::public_key.eq(sentinel_key),
+            schema::useragent_client::key_type.eq(1i32),
+        ))
         .execute(&mut conn)
         .await
         .unwrap();
 }
 
+async fn spawn_test_actors(db: &db::DatabasePool) -> GlobalActors {
+    insert_bootstrap_sentinel_useragent(db).await;
+
+    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+    actors
+        .vault
+        .ask(Bootstrap {
+            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
+        })
+        .await
+        .unwrap();
+    actors
+}
+
 #[tokio::test]
 #[test_log::test]
 pub async fn test_unregistered_pubkey_rejected() {
     let db = db::create_test_pool().await;
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
-    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+    let actors = spawn_test_actors(&db).await;
     let props = ClientConnection::new(db.clone(), actors);
     let task = tokio::spawn(async move {
         let mut server_transport = server_transport;
         connect_client(props, &mut server_transport).await;
     });
 
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key(),
+            pubkey: new_key.verifying_key().into(),
             metadata: metadata("client", Some("desc"), Some("1.0.0")),
         })
         .await
@@ -78,20 +140,19 @@ pub async fn test_unregistered_pubkey_rejected() {
 #[test_log::test]
 pub async fn test_challenge_auth() {
     let db = db::create_test_pool().await;
+    let actors = spawn_test_actors(&db).await;
 
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
 
     insert_registered_client(
         &db,
-        pubkey_bytes.clone(),
+        &actors,
+        new_key.verifying_key(),
         &metadata("client", Some("desc"), Some("1.0.0")),
     )
     .await;
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
-    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
-
     let props = ClientConnection::new(db.clone(), actors);
     let task = tokio::spawn(async move {
         let mut server_transport = server_transport;
@@ -101,7 +162,7 @@ pub async fn test_challenge_auth() {
     // Send challenge request
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key(),
+            pubkey: new_key.verifying_key().into(),
             metadata: metadata("client", Some("desc"), Some("1.0.0")),
         })
         .await
@@ -121,8 +182,7 @@ pub async fn test_challenge_auth() {
     };
 
     // Sign the challenge and send solution
-    let formatted_challenge = arbiter_proto::format_challenge(challenge.1, challenge.0.as_bytes());
-    let signature = new_key.sign(&formatted_challenge);
+    let signature = sign_client_challenge(&new_key, challenge.1, &challenge.0);
 
     test_transport
         .send(auth::Inbound::AuthChallengeSolution { signature })
@@ -147,34 +207,13 @@ pub async fn test_challenge_auth() {
 #[test_log::test]
 pub async fn test_metadata_unchanged_does_not_append_history() {
     let db = db::create_test_pool().await;
-    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
-    let props = ClientConnection::new(db.clone(), actors);
-
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
+    let actors = spawn_test_actors(&db).await;
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
     let requested = metadata("client", Some("desc"), Some("1.0.0"));
 
-    {
-        use arbiter_server::db::schema::{client_metadata, program_client};
-        let mut conn = db.get().await.unwrap();
-        let metadata_id: i32 = insert_into(client_metadata::table)
-            .values((
-                client_metadata::name.eq(&requested.name),
-                client_metadata::description.eq(&requested.description),
-                client_metadata::version.eq(&requested.version),
-            ))
-            .returning(client_metadata::id)
-            .get_result(&mut conn)
-            .await
-            .unwrap();
-        insert_into(program_client::table)
-            .values((
-                program_client::public_key.eq(new_key.verifying_key().to_bytes().to_vec()),
-                program_client::metadata_id.eq(metadata_id),
-            ))
-            .execute(&mut conn)
-            .await
-            .unwrap();
-    }
+    insert_registered_client(&db, &actors, new_key.verifying_key(), &requested).await;
+
+    let props = ClientConnection::new(db.clone(), actors);
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
     let task = tokio::spawn(async move {
@@ -184,7 +223,7 @@ pub async fn test_metadata_unchanged_does_not_append_history() {
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key(),
+            pubkey: new_key.verifying_key().into(),
             metadata: requested,
         })
         .await
@@ -195,7 +234,7 @@ pub async fn test_metadata_unchanged_does_not_append_history() {
         auth::Outbound::AuthChallenge { pubkey, nonce } => (pubkey, nonce),
         other => panic!("Expected AuthChallenge, got {other:?}"),
     };
-    let signature = new_key.sign(&arbiter_proto::format_challenge(nonce, pubkey.as_bytes()));
+    let signature = sign_client_challenge(&new_key, nonce, &pubkey);
     test_transport
         .send(auth::Inbound::AuthChallengeSolution { signature })
         .await
@@ -225,34 +264,19 @@ pub async fn test_metadata_unchanged_does_not_append_history() {
 #[test_log::test]
 pub async fn test_metadata_change_appends_history_and_repoints_binding() {
     let db = db::create_test_pool().await;
-    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+    let actors = spawn_test_actors(&db).await;
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
+
+    insert_registered_client(
+        &db,
+        &actors,
+        new_key.verifying_key(),
+        &metadata("client", Some("old"), Some("1.0.0")),
+    )
+    .await;
+
     let props = ClientConnection::new(db.clone(), actors);
 
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-
-    {
-        use arbiter_server::db::schema::{client_metadata, program_client};
-        let mut conn = db.get().await.unwrap();
-        let metadata_id: i32 = insert_into(client_metadata::table)
-            .values((
-                client_metadata::name.eq("client"),
-                client_metadata::description.eq(Some("old")),
-                client_metadata::version.eq(Some("1.0.0")),
-            ))
-            .returning(client_metadata::id)
-            .get_result(&mut conn)
-            .await
-            .unwrap();
-        insert_into(program_client::table)
-            .values((
-                program_client::public_key.eq(new_key.verifying_key().to_bytes().to_vec()),
-                program_client::metadata_id.eq(metadata_id),
-            ))
-            .execute(&mut conn)
-            .await
-            .unwrap();
-    }
-
     let (server_transport, mut test_transport) = ChannelTransport::new();
     let task = tokio::spawn(async move {
         let mut server_transport = server_transport;
@@ -261,7 +285,7 @@ pub async fn test_metadata_change_appends_history_and_repoints_binding() {
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key(),
+            pubkey: new_key.verifying_key().into(),
             metadata: metadata("client", Some("new"), Some("2.0.0")),
         })
         .await
@@ -272,7 +296,7 @@ pub async fn test_metadata_change_appends_history_and_repoints_binding() {
         auth::Outbound::AuthChallenge { pubkey, nonce } => (pubkey, nonce),
         other => panic!("Expected AuthChallenge, got {other:?}"),
     };
-    let signature = new_key.sign(&arbiter_proto::format_challenge(nonce, pubkey.as_bytes()));
+    let signature = sign_client_challenge(&new_key, nonce, &pubkey);
     test_transport
         .send(auth::Inbound::AuthChallengeSolution { signature })
         .await
@@ -322,3 +346,59 @@ pub async fn test_metadata_change_appends_history_and_repoints_binding() {
         );
     }
 }
+
+#[tokio::test]
+#[test_log::test]
+pub async fn test_challenge_auth_rejects_integrity_tag_mismatch() {
+    let db = db::create_test_pool().await;
+    let actors = spawn_test_actors(&db).await;
+
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
+    let requested = metadata("client", Some("desc"), Some("1.0.0"));
+
+    {
+        use arbiter_server::db::schema::{client_metadata, program_client};
+        let mut conn = db.get().await.unwrap();
+        let metadata_id: i32 = insert_into(client_metadata::table)
+            .values((
+                client_metadata::name.eq(&requested.name),
+                client_metadata::description.eq(&requested.description),
+                client_metadata::version.eq(&requested.version),
+            ))
+            .returning(client_metadata::id)
+            .get_result(&mut conn)
+            .await
+            .unwrap();
+        insert_into(program_client::table)
+            .values((
+                program_client::public_key.eq(new_key.verifying_key().encode().to_vec()),
+                program_client::metadata_id.eq(metadata_id),
+            ))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+    }
+
+    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let props = ClientConnection::new(db.clone(), actors);
+    let task = tokio::spawn(async move {
+        let mut server_transport = server_transport;
+        connect_client(props, &mut server_transport).await;
+    });
+
+    test_transport
+        .send(auth::Inbound::AuthChallengeRequest {
+            pubkey: new_key.verifying_key().into(),
+            metadata: requested,
+        })
+        .await
+        .unwrap();
+
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive auth rejection");
+    assert!(matches!(response, Err(auth::Error::IntegrityCheckFailed)));
+
+    task.await.unwrap();
+}

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

@@ -1,17 +1,20 @@
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_proto::transport::{Bi, Error, Receiver, Sender};
 use arbiter_server::{
-    actors::keyholder::KeyHolder,
+    actors::{GlobalActors, vault::Vault},
     db::{self, schema},
-    safe_cell::{SafeCell, SafeCellHandle as _},
 };
+
 use async_trait::async_trait;
 use diesel::QueryDsl;
 use diesel_async::RunQueryDsl;
 use tokio::sync::mpsc;
 
 #[allow(dead_code)]
-pub async fn bootstrapped_keyholder(db: &db::DatabasePool) -> KeyHolder {
-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+pub async fn bootstrapped_vault(db: &db::DatabasePool) -> Vault {
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
     actor
         .bootstrap(SafeCell::new(b"test-seal-key".to_vec()))
         .await

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

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

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

@@ -1,38 +1,58 @@
+use arbiter_crypto::{
+    authn::{self, USERAGENT_CONTEXT, format_challenge},
+    safecell::{SafeCell, SafeCellHandle as _},
+};
+
 use arbiter_proto::transport::{Receiver, Sender};
 use arbiter_server::{
-    actors::{
-        GlobalActors,
-        bootstrap::GetToken,
-        keyholder::Bootstrap,
-        user_agent::{AuthPublicKey, UserAgentConnection, auth},
-    },
+    actors::{GlobalActors, bootstrap::GetToken, vault::Bootstrap},
+    crypto::integrity,
     db::{self, schema},
-    safe_cell::{SafeCell, SafeCellHandle as _},
+    peers::user_agent::{AuthCredentials, Credentials, UserAgentConnection, auth},
 };
 use diesel::{ExpressionMethods as _, QueryDsl, insert_into};
 use diesel_async::RunQueryDsl;
-use ed25519_dalek::Signer as _;
+use ml_dsa::{KeyGen, MlDsa87, SigningKey, signature::Keypair as _};
 
 use super::common::ChannelTransport;
 
+fn sign_useragent_challenge(
+    key: &SigningKey<MlDsa87>,
+    nonce: i32,
+    pubkey_bytes: &[u8],
+) -> authn::Signature {
+    let challenge = format_challenge(nonce, pubkey_bytes);
+    key.signing_key()
+        .sign_deterministic(&challenge, USERAGENT_CONTEXT)
+        .unwrap()
+        .into()
+}
+
 #[tokio::test]
 #[test_log::test]
 pub async fn test_bootstrap_token_auth() {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+    actors
+        .vault
+        .ask(Bootstrap {
+            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
+        })
+        .await
+        .unwrap();
     let token = actors.bootstrapper.ask(GetToken).await.unwrap().unwrap();
 
-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
     let db_for_task = db.clone();
     let task = tokio::spawn(async move {
         let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        auth::authenticate(&mut props, &mut server_transport).await
     });
 
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
+            pubkey: new_key.verifying_key().into(),
             bootstrap_token: Some(token),
         })
         .await
@@ -55,7 +75,7 @@ pub async fn test_bootstrap_token_auth() {
         .first::<Vec<u8>>(&mut conn)
         .await
         .unwrap();
-    assert_eq!(stored_pubkey, new_key.verifying_key().to_bytes().to_vec());
+    assert_eq!(stored_pubkey, new_key.verifying_key().encode().to_vec());
 }
 
 #[tokio::test]
@@ -64,17 +84,17 @@ pub async fn test_bootstrap_invalid_token_auth() {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
 
-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
     let db_for_task = db.clone();
     let task = tokio::spawn(async move {
         let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        auth::authenticate(&mut props, &mut server_transport).await
     });
 
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
+            pubkey: new_key.verifying_key().into(),
             bootstrap_token: Some("invalid_token".to_string()),
         })
         .await
@@ -99,32 +119,54 @@ pub async fn test_bootstrap_invalid_token_auth() {
 pub async fn test_challenge_auth() {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+    actors
+        .vault
+        .ask(Bootstrap {
+            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
+        })
+        .await
+        .unwrap();
 
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
+    let pubkey_bytes = new_key.verifying_key().encode().to_vec();
 
     {
         let mut conn = db.get().await.unwrap();
-        insert_into(schema::useragent_client::table)
+        let id: i32 = insert_into(schema::useragent_client::table)
             .values((
                 schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
                 schema::useragent_client::key_type.eq(1i32),
             ))
-            .execute(&mut conn)
+            .returning(schema::useragent_client::id)
+            .get_result(&mut conn)
             .await
             .unwrap();
+        integrity::sign_entity(
+            &mut conn,
+            &actors.vault,
+            &AuthCredentials {
+                creds: Credentials {
+                    id,
+                    pubkey: new_key.verifying_key().into(),
+                },
+                new_nonce: 1,
+            },
+            id,
+        )
+        .await
+        .unwrap();
     }
 
-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
     let db_for_task = db.clone();
     let task = tokio::spawn(async move {
         let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        auth::authenticate(&mut props, &mut server_transport).await
     });
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
+            pubkey: new_key.verifying_key().into(),
             bootstrap_token: None,
         })
         .await
@@ -142,12 +184,11 @@ pub async fn test_challenge_auth() {
         Err(err) => panic!("Expected Ok response, got Err({err:?})"),
     };
 
-    let formatted_challenge = arbiter_proto::format_challenge(challenge, &pubkey_bytes);
-    let signature = new_key.sign(&formatted_challenge);
+    let signature = sign_useragent_challenge(&new_key, challenge, &pubkey_bytes);
 
     test_transport
         .send(auth::Inbound::AuthChallengeSolution {
-            signature: signature.to_bytes().to_vec(),
+            signature: signature.to_bytes(),
         })
         .await
         .unwrap();
@@ -171,15 +212,15 @@ pub async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed()
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
 
     actors
-        .key_holder
+        .vault
         .ask(Bootstrap {
             seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
         })
         .await
         .unwrap();
 
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
+    let pubkey_bytes = new_key.verifying_key().encode().to_vec();
 
     {
         let mut conn = db.get().await.unwrap();
@@ -187,23 +228,22 @@ pub async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed()
             .values((
                 schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
                 schema::useragent_client::key_type.eq(1i32),
-                schema::useragent_client::pubkey_integrity_tag.eq(Some(vec![0u8; 32])),
             ))
             .execute(&mut conn)
             .await
             .unwrap();
     }
 
-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
     let db_for_task = db.clone();
     let task = tokio::spawn(async move {
         let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        auth::authenticate(&mut props, &mut server_transport).await
     });
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
+            pubkey: new_key.verifying_key().into(),
             bootstrap_token: None,
         })
         .await
@@ -211,7 +251,7 @@ pub async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed()
 
     assert!(matches!(
         task.await.unwrap(),
-        Err(auth::Error::InvalidChallengeSolution)
+        Err(auth::Error::Internal { .. })
     ));
 }
 
@@ -220,32 +260,54 @@ pub async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed()
 pub async fn test_challenge_auth_rejects_invalid_signature() {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+    actors
+        .vault
+        .ask(Bootstrap {
+            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
+        })
+        .await
+        .unwrap();
 
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
+    let pubkey_bytes = new_key.verifying_key().encode().to_vec();
 
     {
         let mut conn = db.get().await.unwrap();
-        insert_into(schema::useragent_client::table)
+        let id: i32 = insert_into(schema::useragent_client::table)
             .values((
                 schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
                 schema::useragent_client::key_type.eq(1i32),
             ))
-            .execute(&mut conn)
+            .returning(schema::useragent_client::id)
+            .get_result(&mut conn)
             .await
             .unwrap();
+        integrity::sign_entity(
+            &mut conn,
+            &actors.vault,
+            &AuthCredentials {
+                creds: Credentials {
+                    id,
+                    pubkey: new_key.verifying_key().into(),
+                },
+                new_nonce: 1,
+            },
+            id,
+        )
+        .await
+        .unwrap();
     }
 
-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
     let db_for_task = db.clone();
     let task = tokio::spawn(async move {
         let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        auth::authenticate(&mut props, &mut server_transport).await
     });
 
     test_transport
         .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
+            pubkey: new_key.verifying_key().into(),
             bootstrap_token: None,
         })
         .await
@@ -263,12 +325,11 @@ pub async fn test_challenge_auth_rejects_invalid_signature() {
         Err(err) => panic!("Expected Ok response, got Err({err:?})"),
     };
 
-    let wrong_challenge = arbiter_proto::format_challenge(challenge + 1, &pubkey_bytes);
-    let signature = new_key.sign(&wrong_challenge);
+    let signature = sign_useragent_challenge(&new_key, challenge + 1, &pubkey_bytes);
 
     test_transport
         .send(auth::Inbound::AuthChallengeSolution {
-            signature: signature.to_bytes().to_vec(),
+            signature: signature.to_bytes(),
         })
         .await
         .unwrap();

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

@@ -1,50 +1,59 @@
+use arbiter_crypto::{
+    authn,
+    safecell::{SafeCell, SafeCellHandle as _},
+};
 use arbiter_server::{
     actors::{
         GlobalActors,
-        keyholder::{Bootstrap, Seal},
-        user_agent::{
-            UserAgentSession,
-            session::connection::{HandleUnsealEncryptedKey, HandleUnsealRequest, UnsealError},
-        },
+        vault::{Bootstrap, Seal},
     },
     db,
-    safe_cell::{SafeCell, SafeCellHandle as _},
+    peers::user_agent::{
+        AuthCredentials, Credentials,
+        vault_gate::{Error as VaultGateError, HandleHandshake, HandleUnsealEncryptedKey, VaultGate},
+    },
 };
+
 use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
-use diesel::{ExpressionMethods as _, QueryDsl as _, insert_into};
-use diesel_async::RunQueryDsl;
 use kameo::actor::Spawn as _;
+use tokio::sync::oneshot;
 use x25519_dalek::{EphemeralSecret, PublicKey};
 
-async fn setup_sealed_user_agent(
+async fn setup_sealed_gate(
     seal_key: &[u8],
-) -> (db::DatabasePool, kameo::actor::ActorRef<UserAgentSession>) {
+) -> (db::DatabasePool, kameo::actor::ActorRef<VaultGate>, oneshot::Receiver<Result<Credentials, VaultGateError>>) {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
 
     actors
-        .key_holder
+        .vault
         .ask(Bootstrap {
             seal_key_raw: SafeCell::new(seal_key.to_vec()),
         })
         .await
         .unwrap();
-    actors.key_holder.ask(Seal).await.unwrap();
+    actors.vault.ask(Seal).await.unwrap();
 
-    let session = UserAgentSession::spawn(UserAgentSession::new_test(db.clone(), actors));
+    let (promotion_tx, promotion_rx) = oneshot::channel();
+    let pubkey = authn::SigningKey::generate().public_key();
+    let auth_creds = AuthCredentials {
+        creds: Credentials { id: 1, pubkey },
+        new_nonce: 1,
+    };
+    let gate = VaultGate::spawn(VaultGate::new(auth_creds, actors, db.clone(), promotion_tx));
 
-    (db, session)
+    (db, gate, promotion_rx)
 }
 
 async fn client_dh_encrypt(
-    user_agent: &kameo::actor::ActorRef<UserAgentSession>,
+    gate: &kameo::actor::ActorRef<VaultGate>,
     key_to_send: &[u8],
 ) -> HandleUnsealEncryptedKey {
     let client_secret = EphemeralSecret::random();
     let client_public = PublicKey::from(&client_secret);
 
-    let response = user_agent
-        .ask(HandleUnsealRequest {
+    let response = gate
+        .ask(HandleHandshake {
             client_pubkey: client_public,
         })
         .await
@@ -72,26 +81,26 @@ async fn client_dh_encrypt(
 #[test_log::test]
 pub async fn test_unseal_success() {
     let seal_key = b"test-seal-key";
-    let (_db, user_agent) = setup_sealed_user_agent(seal_key).await;
+    let (_db, gate, _promotion_rx) = setup_sealed_gate(seal_key).await;
 
-    let encrypted_key = client_dh_encrypt(&user_agent, seal_key).await;
+    let encrypted_key = client_dh_encrypt(&gate, seal_key).await;
 
-    let response = user_agent.ask(encrypted_key).await;
+    let response = gate.ask(encrypted_key).await;
     assert!(matches!(response, Ok(())));
 }
 
 #[tokio::test]
 #[test_log::test]
 pub async fn test_unseal_wrong_seal_key() {
-    let (_db, user_agent) = setup_sealed_user_agent(b"correct-key").await;
+    let (_db, gate, _promotion_rx) = setup_sealed_gate(b"correct-key").await;
 
-    let encrypted_key = client_dh_encrypt(&user_agent, b"wrong-key").await;
+    let encrypted_key = client_dh_encrypt(&gate, b"wrong-key").await;
 
-    let response = user_agent.ask(encrypted_key).await;
+    let response = gate.ask(encrypted_key).await;
     assert!(matches!(
         response,
         Err(kameo::error::SendError::HandlerError(
-            UnsealError::InvalidKey
+            VaultGateError::InvalidKey
         ))
     ));
 }
@@ -99,19 +108,18 @@ pub async fn test_unseal_wrong_seal_key() {
 #[tokio::test]
 #[test_log::test]
 pub async fn test_unseal_corrupted_ciphertext() {
-    let (_db, user_agent) = setup_sealed_user_agent(b"test-key").await;
+    let (_db, gate, _promotion_rx) = setup_sealed_gate(b"test-key").await;
 
     let client_secret = EphemeralSecret::random();
     let client_public = PublicKey::from(&client_secret);
 
-    user_agent
-        .ask(HandleUnsealRequest {
-            client_pubkey: client_public,
-        })
-        .await
-        .unwrap();
+    gate.ask(HandleHandshake {
+        client_pubkey: client_public,
+    })
+    .await
+    .unwrap();
 
-    let response = user_agent
+    let response = gate
         .ask(HandleUnsealEncryptedKey {
             nonce: vec![0u8; 24],
             ciphertext: vec![0u8; 32],
@@ -122,7 +130,7 @@ pub async fn test_unseal_corrupted_ciphertext() {
     assert!(matches!(
         response,
         Err(kameo::error::SendError::HandlerError(
-            UnsealError::InvalidKey
+            VaultGateError::InvalidKey
         ))
     ));
 }
@@ -131,63 +139,24 @@ pub async fn test_unseal_corrupted_ciphertext() {
 #[test_log::test]
 pub async fn test_unseal_retry_after_invalid_key() {
     let seal_key = b"real-seal-key";
-    let (_db, user_agent) = setup_sealed_user_agent(seal_key).await;
+    let (_db, gate, _promotion_rx) = setup_sealed_gate(seal_key).await;
 
     {
-        let encrypted_key = client_dh_encrypt(&user_agent, b"wrong-key").await;
+        let encrypted_key = client_dh_encrypt(&gate, b"wrong-key").await;
 
-        let response = user_agent.ask(encrypted_key).await;
+        let response = gate.ask(encrypted_key).await;
         assert!(matches!(
             response,
             Err(kameo::error::SendError::HandlerError(
-                UnsealError::InvalidKey
+                VaultGateError::InvalidKey
             ))
         ));
     }
 
     {
-        let encrypted_key = client_dh_encrypt(&user_agent, seal_key).await;
+        let encrypted_key = client_dh_encrypt(&gate, seal_key).await;
 
-        let response = user_agent.ask(encrypted_key).await;
+        let response = gate.ask(encrypted_key).await;
         assert!(matches!(response, Ok(())));
     }
 }
-
-#[tokio::test]
-#[test_log::test]
-pub async fn test_unseal_backfills_missing_pubkey_integrity_tags() {
-    let seal_key = b"test-seal-key";
-    let (db, user_agent) = setup_sealed_user_agent(seal_key).await;
-
-    {
-        let mut conn = db.get().await.unwrap();
-        insert_into(arbiter_server::db::schema::useragent_client::table)
-            .values((
-                arbiter_server::db::schema::useragent_client::public_key
-                    .eq(vec![1u8, 2u8, 3u8, 4u8]),
-                arbiter_server::db::schema::useragent_client::key_type.eq(1i32),
-                arbiter_server::db::schema::useragent_client::pubkey_integrity_tag
-                    .eq(Option::<Vec<u8>>::None),
-            ))
-            .execute(&mut conn)
-            .await
-            .unwrap();
-    }
-
-    let encrypted_key = client_dh_encrypt(&user_agent, seal_key).await;
-    let response = user_agent.ask(encrypted_key).await;
-    assert!(matches!(response, Ok(())));
-
-    {
-        let mut conn = db.get().await.unwrap();
-        let tags: Vec<Option<Vec<u8>>> = arbiter_server::db::schema::useragent_client::table
-            .select(arbiter_server::db::schema::useragent_client::pubkey_integrity_tag)
-            .load(&mut conn)
-            .await
-            .unwrap();
-        assert!(
-            tags.iter()
-                .all(|tag| matches!(tag, Some(v) if v.len() == 32))
-        );
-    }
-}

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

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

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

@@ -1,10 +1,14 @@
 use std::collections::{HashMap, HashSet};
 
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_server::{
-    actors::keyholder::{CreateNew, Error, KeyHolder},
+    actors::{
+        GlobalActors,
+        vault::{CreateNew, Error, Vault},
+    },
     db::{self, models, schema},
-    safe_cell::{SafeCell, SafeCellHandle as _},
 };
+
 use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper, dsl::sql_query};
 use diesel_async::RunQueryDsl;
 use kameo::actor::{ActorRef, Spawn as _};
@@ -13,7 +17,7 @@ use tokio::task::JoinSet;
 use crate::common;
 
 async fn write_concurrently(
-    actor: ActorRef<KeyHolder>,
+    actor: ActorRef<Vault>,
     prefix: &'static str,
     count: usize,
 ) -> Vec<(i32, Vec<u8>)> {
@@ -43,7 +47,7 @@ async fn write_concurrently(
 #[test_log::test]
 async fn concurrent_create_new_no_duplicate_nonces_() {
     let db = db::create_test_pool().await;
-    let actor = KeyHolder::spawn(common::bootstrapped_keyholder(&db).await);
+    let actor = Vault::spawn(common::bootstrapped_vault(&db).await);
 
     let writes = write_concurrently(actor, "nonce-unique", 32).await;
     assert_eq!(writes.len(), 32);
@@ -65,7 +69,7 @@ async fn concurrent_create_new_no_duplicate_nonces_() {
 #[test_log::test]
 async fn concurrent_create_new_root_nonce_never_moves_backward() {
     let db = db::create_test_pool().await;
-    let actor = KeyHolder::spawn(common::bootstrapped_keyholder(&db).await);
+    let actor = Vault::spawn(common::bootstrapped_vault(&db).await);
 
     write_concurrently(actor, "root-max", 24).await;
 
@@ -93,7 +97,7 @@ async fn concurrent_create_new_root_nonce_never_moves_backward() {
 #[test_log::test]
 async fn insert_failure_does_not_create_partial_row() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
     let root_key_history_id = common::root_key_history_id(&db).await;
 
     let mut conn = db.get().await.unwrap();
@@ -155,12 +159,14 @@ async fn insert_failure_does_not_create_partial_row() {
 #[test_log::test]
 async fn decrypt_roundtrip_after_high_concurrency() {
     let db = db::create_test_pool().await;
-    let actor = KeyHolder::spawn(common::bootstrapped_keyholder(&db).await);
+    let actor = Vault::spawn(common::bootstrapped_vault(&db).await);
 
     let writes = write_concurrently(actor, "roundtrip", 40).await;
     let expected: HashMap<i32, Vec<u8>> = writes.into_iter().collect();
 
-    let mut decryptor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut decryptor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
     decryptor
         .try_unseal(SafeCell::new(b"test-seal-key".to_vec()))
         .await

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

@@ -1,9 +1,13 @@
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_server::{
-    actors::keyholder::{Error, KeyHolder},
+    actors::{
+        GlobalActors,
+        vault::{Error, Vault},
+    },
     crypto::encryption::v1::{Nonce, ROOT_KEY_TAG},
     db::{self, models, schema},
-    safe_cell::{SafeCell, SafeCellHandle as _},
 };
+
 use diesel::{QueryDsl, SelectableHelper};
 use diesel_async::RunQueryDsl;
 
@@ -13,7 +17,9 @@ use crate::common;
 #[test_log::test]
 async fn test_bootstrap() {
     let db = db::create_test_pool().await;
-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
 
     let seal_key = SafeCell::new(b"test-seal-key".to_vec());
     actor.bootstrap(seal_key).await.unwrap();
@@ -36,7 +42,7 @@ async fn test_bootstrap() {
 #[test_log::test]
 async fn test_bootstrap_rejects_double() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let seal_key2 = SafeCell::new(b"test-seal-key".to_vec());
     let err = actor.bootstrap(seal_key2).await.unwrap_err();
@@ -47,7 +53,9 @@ async fn test_bootstrap_rejects_double() {
 #[test_log::test]
 async fn test_create_new_before_bootstrap_fails() {
     let db = db::create_test_pool().await;
-    let mut actor = KeyHolder::new(db).await.unwrap();
+    let mut actor = Vault::new(db, GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
 
     let err = actor
         .create_new(SafeCell::new(b"data".to_vec()))
@@ -60,7 +68,9 @@ async fn test_create_new_before_bootstrap_fails() {
 #[test_log::test]
 async fn test_decrypt_before_bootstrap_fails() {
     let db = db::create_test_pool().await;
-    let mut actor = KeyHolder::new(db).await.unwrap();
+    let mut actor = Vault::new(db, GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
 
     let err = actor.decrypt(1).await.unwrap_err();
     assert!(matches!(err, Error::NotBootstrapped));
@@ -70,10 +80,12 @@ async fn test_decrypt_before_bootstrap_fails() {
 #[test_log::test]
 async fn test_new_restores_sealed_state() {
     let db = db::create_test_pool().await;
-    let actor = common::bootstrapped_keyholder(&db).await;
+    let actor = common::bootstrapped_vault(&db).await;
     drop(actor);
 
-    let mut actor2 = KeyHolder::new(db).await.unwrap();
+    let mut actor2 = Vault::new(db, GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
     let err = actor2.decrypt(1).await.unwrap_err();
     assert!(matches!(err, Error::NotBootstrapped));
 }
@@ -82,7 +94,7 @@ async fn test_new_restores_sealed_state() {
 #[test_log::test]
 async fn test_unseal_correct_password() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let plaintext = b"survive a restart";
     let aead_id = actor
@@ -91,7 +103,9 @@ async fn test_unseal_correct_password() {
         .unwrap();
     drop(actor);
 
-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
     let seal_key = SafeCell::new(b"test-seal-key".to_vec());
     actor.try_unseal(seal_key).await.unwrap();
 
@@ -103,7 +117,7 @@ async fn test_unseal_correct_password() {
 #[test_log::test]
 async fn test_unseal_wrong_then_correct_password() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let plaintext = b"important data";
     let aead_id = actor
@@ -112,7 +126,9 @@ async fn test_unseal_wrong_then_correct_password() {
         .unwrap();
     drop(actor);
 
-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
 
     let bad_key = SafeCell::new(b"wrong-password".to_vec());
     let err = actor.try_unseal(bad_key).await.unwrap_err();

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

@@ -1,11 +1,12 @@
 use std::collections::HashSet;
 
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_server::{
-    actors::keyholder::Error,
+    actors::vault::Error,
     crypto::encryption::v1::Nonce,
     db::{self, models, schema},
-    safe_cell::{SafeCell, SafeCellHandle as _},
 };
+
 use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper, dsl::update};
 use diesel_async::RunQueryDsl;
 
@@ -15,7 +16,7 @@ use crate::common;
 #[test_log::test]
 async fn test_create_decrypt_roundtrip() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let plaintext = b"hello arbiter";
     let aead_id = actor
@@ -31,7 +32,7 @@ async fn test_create_decrypt_roundtrip() {
 #[test_log::test]
 async fn test_decrypt_nonexistent_returns_not_found() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let err = actor.decrypt(9999).await.unwrap_err();
     assert!(matches!(err, Error::NotFound));
@@ -41,7 +42,7 @@ async fn test_decrypt_nonexistent_returns_not_found() {
 #[test_log::test]
 async fn test_ciphertext_differs_across_entries() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let plaintext = b"same content";
     let id1 = actor
@@ -79,7 +80,7 @@ async fn test_ciphertext_differs_across_entries() {
 #[test_log::test]
 async fn test_nonce_never_reused() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
 
     let n = 5;
     for i in 0..n {
@@ -123,7 +124,7 @@ async fn test_nonce_never_reused() {
 #[test_log::test]
 async fn broken_db_nonce_format_fails_closed() {
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
     let root_key_history_id = common::root_key_history_id(&db).await;
 
     let mut conn = db.get().await.unwrap();
@@ -144,7 +145,7 @@ async fn broken_db_nonce_format_fails_closed() {
     assert!(matches!(err, Error::BrokenDatabase));
 
     let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
     let id = actor
         .create_new(SafeCell::new(b"decrypt target".to_vec()))
         .await

useragent/flutter_rust_bridge.yaml

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

useragent/lib/features/callouts/callout_event.dart

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

useragent/lib/features/callouts/show_callout.dart

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

useragent/lib/features/callouts/show_callout_list.dart

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

useragent/lib/features/connection/arbiter_url.dart

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

useragent/lib/features/connection/auth.dart

@@ -61,11 +61,6 @@ Future<Connection> connectAndAuthorize(
     final req = ua_auth.AuthChallengeRequest(
       pubkey: pubkey,
       bootstrapToken: bootstrapToken,
-      keyType: switch (key.alg) {
-        KeyAlgorithm.rsa => ua_auth.KeyType.KEY_TYPE_RSA,
-        KeyAlgorithm.ecdsa => ua_auth.KeyType.KEY_TYPE_ECDSA_SECP256K1,
-        KeyAlgorithm.ed25519 => ua_auth.KeyType.KEY_TYPE_ED25519,
-      },
     );
     final response = await connection.ask(
       UserAgentRequest(auth: ua_auth.Request(challengeRequest: req)),
@@ -106,7 +101,9 @@ Future<Connection> connectAndAuthorize(
     final solutionResponse = await connection.ask(
       UserAgentRequest(
         auth: ua_auth.Request(
-          challengeSolution: ua_auth.AuthChallengeSolution(signature: signature),
+          challengeSolution: ua_auth.AuthChallengeSolution(
+            signature: signature,
+          ),
         ),
       ),
     );

useragent/lib/features/connection/connection.dart

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

useragent/lib/features/connection/evm.dart

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

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

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

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

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

useragent/lib/features/connection/server_info_storage.dart

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

useragent/lib/features/connection/vault.dart

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