merge: refactor-integrity-check into main

2026-04-18 13:40:46 +02:00
parent 28f84d03ab 929d50b589
commit 9cf87b2058
205 changed files with 14330 additions and 2667 deletions
--- a/AGENTS.md
+++ b/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.

--- a/CLAUDE.md
+++ b/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.

--- a/IMPLEMENTATION.md
+++ b/IMPLEMENTATION.md
@@ -29,38 +29,23 @@ flowchart TD
    A([Client connects]) --> B[Receive AuthChallengeRequest]
    B --> C{pubkey in DB?}

-    C -- yes --> D[Read nonce\nIncrement nonce in DB]
-    D --> G
+    C -- yes --> G[Generate AuthChallenge]

    C -- no --> E[Ask all UserAgents:\nClientConnectionRequest]
    E --> F{First response}
    F -- denied --> Z([Reject connection])
    F -- approved --> F2[Cancel remaining\nUserAgent requests]
-    F2 --> F3[INSERT client\nnonce = 1]
-    F3 --> G[Send AuthChallenge\nwith nonce]
+    F2 --> F3[INSERT client]
+    F3 --> G

-    G --> H[Receive AuthChallengeSolution]
-    H --> I{Signature valid?}
-    I -- no --> Z
-    I -- yes --> J([Session started])
+    G --> H[Send AuthChallenge\ntimestamp + random bytes]
+    H --> I[Receive AuthChallengeSolution]
+    I --> K{Signature valid?}
+    K -- no --> Z
+    K -- yes --> J([Session started])
 ```

-### Known Issue: Concurrent Registration Race (TOCTOU)
-
-Two connections presenting the same previously-unknown public key can race through the approval flow simultaneously:
-
-1. Both check the DB → neither is registered.
-2. Both request approval from user agents → both receive approval.
-3. Both `INSERT` the client record → the second insert silently overwrites the first, resetting the nonce.
-
-This means the first connection's nonce is invalidated by the second, causing its challenge verification to fail. A fix requires either serialising new-client registration (e.g. an in-memory lock keyed on pubkey) or replacing the separate check + insert with an `INSERT OR IGNORE` / upsert guarded by a unique constraint on `public_key`.
-
-### Nonce Semantics
-
-The `program_client.nonce` column stores the **next usable nonce** — i.e. it is always one ahead of the nonce last issued in a challenge.
-
- **New client:** inserted with `nonce = 1`; the first challenge is issued with `nonce = 0`.
- **Existing client:** the current DB value is read and used as the challenge nonce, then immediately incremented within the same exclusive transaction, preventing replay.
+Auth challenges are generated from fresh random bytes plus a timestamp. They are signed as the canonical challenge payload and are not persisted in `program_client`.

 ---

--- a/mise.lock
+++ b/mise.lock
@@ -72,6 +72,10 @@ backend = "cargo:diesel_cli"
 default-features = "false"
 features = "sqlite,sqlite-bundled"

+[[tools."cargo:flutter_rust_bridge_codegen"]]
+version = "2.12.0"
+backend = "cargo:flutter_rust_bridge_codegen"
+
 [[tools.flutter]]
 version = "3.38.9-stable"
 backend = "asdf:flutter"
--- a/mise.toml
+++ b/mise.toml
@@ -13,6 +13,7 @@ python = "3.14.3"
 ast-grep = "0.42.0"
 "cargo:cargo-edit" = "0.13.9"
 "cargo:cargo-mutants" = "27.0.0"
+"cargo:flutter_rust_bridge_codegen" = "2.12.0"

 [tasks.codegen]
 sources = ['protobufs/*.proto', 'protobufs/**/*.proto']
--- a/protobufs/client/auth.proto
+++ b/protobufs/client/auth.proto
@@ -10,8 +10,8 @@ message AuthChallengeRequest {
 }

 message AuthChallenge {
-  bytes pubkey = 1;
-  int32 nonce = 2;
+  uint64 timestamp_nanos = 1;
+  bytes random = 2;
 }

 message AuthChallengeSolution {
--- a/protobufs/user_agent/auth.proto
+++ b/protobufs/user_agent/auth.proto
@@ -2,21 +2,14 @@ syntax = "proto3";

 package arbiter.user_agent.auth;

-enum KeyType {
-  KEY_TYPE_UNSPECIFIED = 0;
-  KEY_TYPE_ED25519 = 1;
-  KEY_TYPE_ECDSA_SECP256K1 = 2;
-  KEY_TYPE_RSA = 3;
-}
-
 message AuthChallengeRequest {
  bytes pubkey = 1;
  optional string bootstrap_token = 2;
-  KeyType key_type = 3;
 }

 message AuthChallenge {
-  int32 nonce = 1;
+  uint64 timestamp_nanos = 1;
+  bytes random = 2;
 }

 message AuthChallengeSolution {
--- a/server/Cargo.lock
+++ b/server/Cargo.lock
@@ -95,7 +95,7 @@ dependencies = [
 "either",
 "k256",
 "once_cell",
- "rand 0.8.5",
+ "rand 0.8.6",
 "secp256k1",
 "serde",
 "serde_json",
@@ -520,7 +520,7 @@ dependencies = [
 "alloy-signer",
 "async-trait",
 "k256",
- "rand 0.8.5",
+ "rand 0.8.6",
 "thiserror 2.0.18",
 ]

@@ -687,6 +687,7 @@ dependencies = [
 "arbiter-crypto",
 "arbiter-proto",
 "async-trait",
+ "chrono",
 "http",
 "rand 0.10.1",
 "rustls-webpki",
@@ -701,12 +702,12 @@ name = "arbiter-crypto"
 version = "0.1.0"
 dependencies = [
 "alloy",
- "base64",
 "chrono",
 "hmac 0.13.0",
 "memsafe",
 "ml-dsa",
 "rand 0.10.1",
+ "x-wing",
 ]

 [[package]]
@@ -771,6 +772,7 @@ dependencies = [
 "insta",
 "k256",
 "kameo",
+ "kameo_actors",
 "ml-dsa",
 "mutants",
 "pem",
@@ -796,7 +798,7 @@ dependencies = [
 "tonic",
 "tracing",
 "tracing-subscriber",
- "x25519-dalek",
+ "x25519-dalek 2.0.1",
 "zeroize",
 ]

@@ -986,7 +988,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1df2c09229cbc5a028b1d70e00fdb2acee28b1055dfb5ca73eea49c5a25c4e7c"
 dependencies = [
 "num-traits",
- "rand 0.8.5",
+ "rand 0.8.6",
 ]

 [[package]]
@@ -996,7 +998,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94893f1e0c6eeab764ade8dc4c0db24caf4fe7cbbaafc0eba0a9030f447b5185"
 dependencies = [
 "num-traits",
- "rand 0.8.5",
+ "rand 0.8.6",
 ]

 [[package]]
@@ -1006,7 +1008,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "246a225cc6131e9ee4f24619af0f19d67761fff15d7ccc22e42b80846e69449a"
 dependencies = [
 "num-traits",
- "rand 0.8.5",
+ "rand 0.8.6",
 ]

 [[package]]
@@ -1112,9 +1114,9 @@ checksum = "c08606f8c3cbf4ce6ec8e28fb0014a2c086708fe954eaa885384a6165172e7e8"

 [[package]]
 name = "aws-lc-rs"
-version = "1.16.2"
+version = "1.16.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a054912289d18629dc78375ba2c3726a3afe3ff71b4edba9dedfca0e3446d1fc"
+checksum = "0ec6fb3fe69024a75fa7e1bfb48aa6cf59706a101658ea01bfd33b2b248a038f"
 dependencies = [
 "aws-lc-sys",
 "untrusted 0.7.1",
@@ -1123,9 +1125,9 @@ dependencies = [

 [[package]]
 name = "aws-lc-sys"
-version = "0.39.1"
+version = "0.40.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "83a25cf98105baa966497416dbd42565ce3a8cf8dbfd59803ec9ad46f3126399"
+checksum = "f50037ee5e1e41e7b8f9d161680a725bd1626cb6f8c7e901f91f942850852fe7"
 dependencies = [
 "cc",
 "cmake",
@@ -1536,11 +1538,12 @@ checksum = "a6ef517f0926dd24a1582492c791b6a4818a4d94e789a334894aa15b0d12f55c"

 [[package]]
 name = "const_format"
-version = "0.2.35"
+version = "0.2.36"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7faa7469a93a566e9ccc1c73fe783b4a65c274c5ace346038dca9c39fe0030ad"
+checksum = "4481a617ad9a412be3b97c5d403fef8ed023103368908b9c50af598ff467cc1e"
 dependencies = [
 "const_format_proc_macros",
+ "konst",
 ]

 [[package]]
@@ -1663,6 +1666,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "77727bb15fa921304124b128af125e7e3b968275d1b108b379190264f4423710"
 dependencies = [
 "hybrid-array",
+ "rand_core 0.10.1",
 ]

 [[package]]
@@ -2258,7 +2262,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "835c052cb0c08c1acf6ffd71c022172e18723949c8282f2b9f27efbc51e64534"
 dependencies = [
 "byteorder",
- "rand 0.8.5",
+ "rand 0.8.6",
 "rustc-hex",
 "static_assertions",
 ]
@@ -2657,6 +2661,7 @@ version = "0.4.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3944cf8cf766b40e2a1a333ee5e9b563f854d5fa49d6a8ca2764e97c6eddb214"
 dependencies = [
+ "ctutils",
 "typenum",
 "zeroize",
 ]
@@ -3076,8 +3081,7 @@ dependencies = [
 [[package]]
 name = "kameo"
 version = "0.20.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b1dfd134d7a2c6ec05ee696dcbf3f7a034bdb97ecc623e981014652dcd124d77"
+source = "git+https://github.com/hdbg/kameo.git?rev=805b417#805b41783fe90b54827ecad142b422c7a9b69b9a"
 dependencies = [
 "downcast-rs",
 "dyn-clone",
@@ -3088,12 +3092,24 @@ dependencies = [
 "tracing",
 ]

+[[package]]
+name = "kameo_actors"
+version = "0.5.0"
+source = "git+https://github.com/hdbg/kameo.git?rev=805b417#805b41783fe90b54827ecad142b422c7a9b69b9a"
+dependencies = [
+ "futures",
+ "glob",
+ "kameo",
+ "thiserror 2.0.18",
+ "tokio",
+]
+
 [[package]]
 name = "kameo_macros"
 version = "0.20.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "16c9002c9ecd16e1636f566c0bf62db48e70d86ed0d0a91b398955e883217a23"
+source = "git+https://github.com/hdbg/kameo.git?rev=805b417#805b41783fe90b54827ecad142b422c7a9b69b9a"
 dependencies = [
+ "darling 0.23.0",
 "heck",
 "proc-macro2",
 "quote",
@@ -3129,6 +3145,31 @@ dependencies = [
 "sha3-asm",
 ]

+[[package]]
+name = "kem"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "01737161ba802849cfd486b5bd209d38ba4943494c249a8126005170c7621edd"
+dependencies = [
+ "crypto-common 0.2.1",
+ "rand_core 0.10.1",
+]
+
+[[package]]
+name = "konst"
+version = "0.2.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "128133ed7824fcd73d6e7b17957c5eb7bacb885649bd8c69708b2331a10bcefb"
+dependencies = [
+ "konst_macro_rules",
+]
+
+[[package]]
+name = "konst_macro_rules"
+version = "0.2.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a4933f3f57a8e9d9da04db23fb153356ecaf00cbd14aee46279c33dc80925c37"
+
 [[package]]
 name = "lazy_static"
 version = "1.5.0"
@@ -3349,12 +3390,27 @@ dependencies = [
 "zeroize",
 ]

+[[package]]
+name = "ml-kem"
+version = "0.3.0-rc.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "04437cb1a66c0b78740927b76cc61f218344b9f6ef3dd430e283274a718ef0e9"
+dependencies = [
+ "hybrid-array",
+ "kem",
+ "module-lattice",
+ "rand_core 0.10.1",
+ "sha3 0.11.0",
+ "zeroize",
+]
+
 [[package]]
 name = "module-lattice"
 version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "164eb3faeaecbd14b0b2a917c1b4d0c035097a9c559b0bed85c2cdd032bc8faa"
 dependencies = [
+ "ctutils",
 "hybrid-array",
 "num-traits",
 "zeroize",
@@ -4050,9 +4106,9 @@ checksum = "dc33ff2d4973d518d823d61aa239014831e521c75da58e3df4840d3f47749d09"

 [[package]]
 name = "rand"
-version = "0.8.5"
+version = "0.8.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
+checksum = "5ca0ecfa931c29007047d1bc58e623ab12e5590e8c7cc53200d5202b69266d8a"
 dependencies = [
 "libc",
 "rand_chacha 0.3.1",
@@ -4365,7 +4421,7 @@ dependencies = [
 "parity-scale-codec",
 "primitive-types",
 "proptest",
- "rand 0.8.5",
+ "rand 0.8.6",
 "rand 0.9.4",
 "rlp",
 "ruint-macro",
@@ -4611,7 +4667,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b50c5943d326858130af85e049f2661ba3c78b26589b8ab98e65e80ae44a1252"
 dependencies = [
 "bitcoin_hashes",
- "rand 0.8.5",
+ "rand 0.8.6",
 "secp256k1-sys",
 "serde",
 ]
@@ -5284,9 +5340,9 @@ checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"

 [[package]]
 name = "tokio"
-version = "1.51.1"
+version = "1.52.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f66bf9585cda4b724d3e78ab34b73fb2bbaba9011b9bfdf69dc836382ea13b8c"
+checksum = "b67dee974fe86fd92cc45b7a95fdd2f99a36a6d7b0d431a231178d3d670bbcc6"
 dependencies = [
 "bytes",
 "libc",
@@ -5700,9 +5756,9 @@ checksum = "b6c140620e7ffbb22c2dee59cafe6084a59b5ffc27a8859a5f0d494b5d52b6be"

 [[package]]
 name = "uuid"
-version = "1.23.0"
+version = "1.23.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5ac8b6f42ead25368cf5b098aeb3dc8a1a2c05a3eee8a9a1a68c640edbfc79d9"
+checksum = "ddd74a9687298c6858e9b88ec8935ec45d22e8fd5e6394fa1bd4e99a87789c76"
 dependencies = [
 "js-sys",
 "wasm-bindgen",
@@ -5762,11 +5818,11 @@ checksum = "ccf3ec651a847eb01de73ccad15eb7d99f80485de043efb2f370cd654f4ea44b"

 [[package]]
 name = "wasip2"
-version = "1.0.2+wasi-0.2.9"
+version = "1.0.3+wasi-0.2.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9517f9239f02c069db75e65f174b3da828fe5f5b945c4dd26bd25d89c03ebcf5"
+checksum = "20064672db26d7cdc89c7798c48a0fdfac8213434a1186e5ef29fd560ae223d6"
 dependencies = [
- "wit-bindgen",
+ "wit-bindgen 0.57.1",
 ]

 [[package]]
@@ -5775,7 +5831,7 @@ version = "0.4.0+wasi-0.3.0-rc-2026-01-06"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5428f8bf88ea5ddc08faddef2ac4a67e390b88186c703ce6dbd955e1c145aca5"
 dependencies = [
- "wit-bindgen",
+ "wit-bindgen 0.51.0",
 ]

 [[package]]
@@ -5903,9 +5959,9 @@ dependencies = [

 [[package]]
 name = "webpki-root-certs"
-version = "1.0.6"
+version = "1.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "804f18a4ac2676ffb4e8b5b5fa9ae38af06df08162314f96a68d2a363e21a8ca"
+checksum = "f31141ce3fc3e300ae89b78c0dd67f9708061d1d2eda54b8209346fd6be9a92c"
 dependencies = [
 "rustls-pki-types",
 ]
@@ -6249,6 +6305,12 @@ dependencies = [
 "wit-bindgen-rust-macro",
 ]

+[[package]]
+name = "wit-bindgen"
+version = "0.57.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ebf944e87a7c253233ad6766e082e3cd714b5d03812acc24c318f549614536e"
+
 [[package]]
 name = "wit-bindgen-core"
 version = "0.51.0"
@@ -6343,6 +6405,20 @@ dependencies = [
 "tap",
 ]

+[[package]]
+name = "x-wing"
+version = "0.1.0-rc.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e17d0d5f4d1f26b9b9e7477af1d3bef960e1d1fb64edab7912fde472a8a8432e"
+dependencies = [
+ "kem",
+ "ml-kem",
+ "rand_core 0.10.1",
+ "sha3 0.11.0",
+ "x25519-dalek 3.0.0-pre.6",
+ "zeroize",
+]
+
 [[package]]
 name = "x25519-dalek"
 version = "2.0.1"
@@ -6355,6 +6431,17 @@ dependencies = [
 "zeroize",
 ]

+[[package]]
+name = "x25519-dalek"
+version = "3.0.0-pre.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b3d5d6ff67acd3945b933e592bfa7143db4fcbb2f871754b6b9fbd7847fc5aea"
+dependencies = [
+ "curve25519-dalek 5.0.0-pre.6",
+ "rand_core 0.10.1",
+ "zeroize",
+]
+
 [[package]]
 name = "x509-parser"
 version = "0.18.1"
--- a/server/Cargo.toml
+++ b/server/Cargo.toml
@@ -16,7 +16,7 @@ tonic = { version = "0.14.5", features = [
    "zstd",
 ] }
 tracing = "0.1.44"
-tokio = { version = "1.51.1", features = ["full"] }
+tokio = { version = "1.52.1", features = ["full"] }
 ed25519-dalek = { version = "3.0.0-pre.6", features = ["rand_core"] }
 chrono = { version = "0.4.44", features = ["serde"] }
 rand = "0.10.1"
@@ -26,7 +26,6 @@ thiserror = "2.0.18"
 async-trait = "0.1.89"
 futures = "0.3.32"
 tokio-stream = { version = "0.1.18", features = ["full"] }
-kameo = "0.20.0"
 prost-types = { version = "0.14.3", features = ["chrono"] }
 x25519-dalek = { version = "2.0.1", features = ["getrandom"] }
 rstest = "0.26.1"
@@ -47,4 +46,6 @@ miette = { version = "7.6.0", features = ["fancy", "serde"] }
 mutants = "0.0.4"
 ml-dsa = { version = "0.1.0-rc.8", features = ["zeroize"] }
 base64 = "0.22.1"
+kameo = {git = "https://github.com/hdbg/kameo.git", rev = "805b417"}
+kameo_actors = {git = "https://github.com/hdbg/kameo.git", rev = "805b417"}
 hmac = "0.13.0"
--- a/server/crates/arbiter-client/Cargo.toml
+++ b/server/crates/arbiter-client/Cargo.toml
@@ -24,3 +24,4 @@ http = "1.4.0"
 rustls-webpki = { version = "0.103.12", features = ["aws-lc-rs"] }
 async-trait.workspace = true
 rand.workspace = true
+chrono.workspace = true
--- a/server/crates/arbiter-client/src/auth.rs
+++ b/server/crates/arbiter-client/src/auth.rs
@@ -1,4 +1,8 @@
-use arbiter_crypto::authn::{CLIENT_CONTEXT, SigningKey, format_challenge};
+use crate::{
+    storage::StorageError,
+    transport::{ClientTransport, next_request_id},
+};
+use arbiter_crypto::authn::{self, CLIENT_CONTEXT, SigningKey};
 use arbiter_proto::{
    ClientMetadata,
    proto::{
@@ -16,13 +20,12 @@ use arbiter_proto::{
    },
 };

-use crate::{
-    storage::StorageError,
-    transport::{ClientTransport, next_request_id},
-};
+use chrono::DateTime;

 #[derive(Debug, thiserror::Error)]
 pub enum AuthError {
+    #[error("Server sent invalid auth challenge")]
+    InvalidChallenge,
    #[error("Auth challenge was not returned by server")]
    MissingAuthChallenge,

@@ -98,7 +101,15 @@ async fn send_auth_challenge_solution(
    key: &SigningKey,
    challenge: AuthChallenge,
 ) -> std::result::Result<(), AuthError> {
-    let challenge_payload = format_challenge(challenge.nonce, &challenge.pubkey);
+    let timestamp = DateTime::from_timestamp_nanos(challenge.timestamp_nanos as i64);
+    let challenge = authn::AuthChallenge {
+        nonce: *challenge
+            .random
+            .as_array()
+            .ok_or(AuthError::InvalidChallenge)?,
+        timestamp,
+    };
+    let challenge_payload: Vec<u8> = challenge.format();
    let signature = key
        .sign_message(&challenge_payload, CLIENT_CONTEXT)
        .map_err(|_| AuthError::UnexpectedAuthResponse)?
--- a/server/crates/arbiter-client/src/bin/test_connect.rs
+++ b/server/crates/arbiter-client/src/bin/test_connect.rs
@@ -1,8 +1,8 @@
-use std::io::{self, Write};
-
 use arbiter_client::ArbiterClient;
 use arbiter_proto::{ClientMetadata, url::ArbiterUrl};

+use std::io::{self, Write};
+
 #[tokio::main]
 async fn main() {
    println!("Testing connection to Arbiter server...");
--- a/server/crates/arbiter-client/src/client.rs
+++ b/server/crates/arbiter-client/src/client.rs
@@ -1,21 +1,20 @@
-use arbiter_crypto::authn::SigningKey;
-use arbiter_proto::{
-    ClientMetadata, proto::arbiter_service_client::ArbiterServiceClient, url::ArbiterUrl,
-};
-use std::sync::Arc;
-use tokio::sync::{Mutex, mpsc};
-use tokio_stream::wrappers::ReceiverStream;
-use tonic::transport::ClientTlsConfig;
-
+#[cfg(feature = "evm")]
+use crate::wallets::evm::ArbiterEvmWallet;
 use crate::{
    StorageError,
    auth::{AuthError, authenticate},
    storage::{FileSigningKeyStorage, SigningKeyStorage},
    transport::{BUFFER_LENGTH, ClientTransport},
 };
+use arbiter_crypto::authn::SigningKey;
+use arbiter_proto::{
+    ClientMetadata, proto::arbiter_service_client::ArbiterServiceClient, url::ArbiterUrl,
+};

-#[cfg(feature = "evm")]
-use crate::wallets::evm::ArbiterEvmWallet;
+use std::sync::Arc;
+use tokio::sync::{Mutex, mpsc};
+use tokio_stream::wrappers::ReceiverStream;
+use tonic::transport::ClientTlsConfig;

 #[derive(Debug, thiserror::Error)]
 pub enum Error {
--- a/server/crates/arbiter-client/src/storage.rs
+++ b/server/crates/arbiter-client/src/storage.rs
@@ -1,5 +1,6 @@
 use arbiter_crypto::authn::SigningKey;
 use arbiter_proto::home_path;
+
 use std::path::{Path, PathBuf};

 #[derive(Debug, thiserror::Error)]
--- a/server/crates/arbiter-client/src/transport.rs
+++ b/server/crates/arbiter-client/src/transport.rs
@@ -1,4 +1,5 @@
 use arbiter_proto::proto::client::{ClientRequest, ClientResponse};
+
 use std::sync::atomic::{AtomicI32, Ordering};
 use tokio::sync::mpsc;

--- a/server/crates/arbiter-client/src/wallets/evm.rs
+++ b/server/crates/arbiter-client/src/wallets/evm.rs
@@ -1,13 +1,4 @@
-use alloy::{
-    consensus::SignableTransaction,
-    network::TxSigner,
-    primitives::{Address, B256, ChainId, Signature},
-    signers::{Error, Result, Signer},
-};
-use async_trait::async_trait;
-use std::sync::Arc;
-use tokio::sync::Mutex;
-
+use crate::transport::{ClientTransport, next_request_id};
 use arbiter_proto::proto::{
    client::{
        ClientRequest,
@@ -25,7 +16,15 @@ use arbiter_proto::proto::{
    shared::evm::TransactionEvalError,
 };

-use crate::transport::{ClientTransport, next_request_id};
+use alloy::{
+    consensus::SignableTransaction,
+    network::TxSigner,
+    primitives::{Address, B256, ChainId, Signature},
+    signers::{Error, Result, Signer},
+};
+use async_trait::async_trait;
+use std::sync::Arc;
+use tokio::sync::Mutex;

 /// A typed error payload returned by [`ArbiterEvmWallet`] transaction signing.
 ///
--- a/server/crates/arbiter-crypto/Cargo.toml
+++ b/server/crates/arbiter-crypto/Cargo.toml
@@ -6,10 +6,10 @@ edition = "2024"
 [dependencies]
 ml-dsa = {workspace = true, optional = true }
 rand = {workspace = true, optional = true}
-base64 = {workspace = true, optional = true }
 memsafe = {version = "0.4.0", optional = true}
 hmac.workspace = true
 alloy.workspace = true
+x-wing = { version = "0.1.0-rc.0", features = ["zeroize"] }
 chrono.workspace = true

 [lints]
@@ -17,5 +17,5 @@ workspace = true

 [features]
 default = ["authn", "safecell"]
-authn = ["dep:ml-dsa", "dep:rand", "dep:base64"]
+authn = ["dep:ml-dsa", "dep:rand"]
 safecell = ["dep:memsafe"]
--- a/server/crates/arbiter-crypto/src/authn/v1.rs
+++ b/server/crates/arbiter-crypto/src/authn/v1.rs
@@ -1,16 +1,55 @@
-use base64::{Engine as _, prelude::BASE64_STANDARD};
+use chrono::{DateTime, Utc};
 use hmac::digest::Digest;
 use ml_dsa::{
    EncodedVerifyingKey, Error, KeyGen, MlDsa87, Seed, Signature as MlDsaSignature,
    SigningKey as MlDsaSigningKey, VerifyingKey as MlDsaVerifyingKey, signature::Keypair as _,
 };
+use rand::RngExt;

 pub static CLIENT_CONTEXT: &[u8] = b"arbiter_client";
 pub static USERAGENT_CONTEXT: &[u8] = b"arbiter_user_agent";

-pub fn format_challenge(nonce: i32, pubkey: &[u8]) -> Vec<u8> {
-    let concat_form = format!("{}:{}", nonce, BASE64_STANDARD.encode(pubkey));
-    concat_form.into_bytes()
+const NONCE_SIZE: usize = 32;
+
+#[derive(Debug, Clone)]
+pub struct AuthChallenge {
+    pub nonce: [u8; NONCE_SIZE],
+    pub timestamp: DateTime<Utc>,
+}
+
+impl AuthChallenge {
+    pub fn generate(rng: &mut impl rand::CryptoRng) -> Self {
+        let timestamp = Utc::now();
+        let nonce = {
+            let mut array = [0; NONCE_SIZE];
+            rng.fill(&mut array);
+            array
+        };
+
+        Self { nonce, timestamp }
+    }
+
+    pub fn format(&self) -> Vec<u8> {
+        {
+            let mut buffer = Vec::from(self.nonce);
+
+            let stamp = self
+                .timestamp
+                .timestamp_nanos_opt()
+                .expect("We would be long dead by the time this triggers :)");
+            buffer.extend_from_slice(stamp.to_be_bytes().as_slice());
+
+            buffer
+        }
+    }
+
+    pub fn from_parts(nonce: &[u8], timestamp: i64) -> Result<Self, ()> {
+        let random_nonce = nonce.as_array().ok_or(())?;
+        Ok(AuthChallenge {
+            nonce: *random_nonce,
+            timestamp: DateTime::from_timestamp_nanos(timestamp),
+        })
+    }
 }

 pub type KeyParams = MlDsa87;
@@ -35,12 +74,10 @@ impl PublicKey {
        self.0.encode().0.to_vec()
    }

-    pub fn verify(&self, nonce: i32, context: &[u8], signature: &Signature) -> bool {
-        self.0.verify_with_context(
-            &format_challenge(nonce, &self.to_bytes()),
-            context,
-            &signature.0,
-        )
+    pub fn verify(&self, challenge: &AuthChallenge, context: &[u8], signature: &Signature) -> bool {
+        let challenge = challenge.format();
+        self.0
+            .verify_with_context(&challenge, context, &signature.0)
    }
 }

@@ -74,11 +111,14 @@ impl SigningKey {
            .map(Into::into)
    }

-    pub fn sign_challenge(&self, nonce: i32, context: &[u8]) -> Result<Signature, Error> {
-        self.sign_message(
-            &format_challenge(nonce, &self.public_key().to_bytes()),
-            context,
-        )
+    pub fn sign_challenge(
+        &self,
+        challenge: &AuthChallenge,
+        context: &[u8],
+    ) -> Result<Signature, Error> {
+        let challenge = challenge.format();
+
+        self.sign_message(&challenge, context)
    }
 }

@@ -139,6 +179,8 @@ impl TryFrom<&'_ [u8]> for Signature {
 mod tests {
    use ml_dsa::{KeyGen, MlDsa87, signature::Keypair as _};

+    use crate::authn::AuthChallenge;
+
    use super::{CLIENT_CONTEXT, PublicKey, Signature, SigningKey, USERAGENT_CONTEXT};

    #[test]
@@ -168,13 +210,13 @@ mod tests {
    fn challenge_verification_uses_context_and_canonical_key_bytes() {
        let key = SigningKey::generate();
        let public_key = key.public_key();
-        let nonce = 17;
+        let challenge = AuthChallenge::generate(&mut rand::rng());
        let signature = key
-            .sign_challenge(nonce, CLIENT_CONTEXT)
+            .sign_challenge(&challenge, CLIENT_CONTEXT)
            .expect("signature should be created");

-        assert!(public_key.verify(nonce, CLIENT_CONTEXT, &signature));
-        assert!(!public_key.verify(nonce, USERAGENT_CONTEXT, &signature));
+        assert!(public_key.verify(&challenge, CLIENT_CONTEXT, &signature));
+        assert!(!public_key.verify(&challenge, USERAGENT_CONTEXT, &signature));
    }

    #[test]
@@ -184,10 +226,16 @@ mod tests {

        assert_eq!(restored.public_key(), original.public_key());

+        let challenge = AuthChallenge::generate(&mut rand::rng());
+
        let signature = restored
-            .sign_challenge(9, CLIENT_CONTEXT)
+            .sign_challenge(&challenge, CLIENT_CONTEXT)
            .expect("signature should be created");

-        assert!(restored.public_key().verify(9, CLIENT_CONTEXT, &signature));
+        assert!(
+            restored
+                .public_key()
+                .verify(&challenge, CLIENT_CONTEXT, &signature)
+        );
    }
 }
--- a/server/crates/arbiter-crypto/src/hashing.rs
+++ b/server/crates/arbiter-crypto/src/hashing.rs
@@ -1,6 +1,7 @@
-pub use hmac::digest::Digest;
 use std::collections::HashSet;

+pub use hmac::digest::Digest;
+
 /// Deterministically hash a value by feeding its fields into the hasher in a consistent order.
 #[diagnostic::on_unimplemented(
    note = "for local types consider adding `#[derive(arbiter_macros::Hashable)]` to your `{Self}` type",
--- a/server/crates/arbiter-crypto/src/lib.rs
+++ b/server/crates/arbiter-crypto/src/lib.rs
@@ -3,3 +3,5 @@ pub mod authn;
 pub mod hashing;
 #[cfg(feature = "safecell")]
 pub mod safecell;
+
+pub use x_wing;
--- a/server/crates/arbiter-crypto/src/safecell.rs
+++ b/server/crates/arbiter-crypto/src/safecell.rs
@@ -1,7 +1,9 @@
-use std::ops::{Deref, DerefMut};
-use std::{any::type_name, fmt};
-
 use memsafe::MemSafe;
+use std::{
+    any::type_name,
+    fmt,
+    ops::{Deref, DerefMut},
+};

 pub trait SafeCellHandle<T> {
    type CellRead<'a>: Deref<Target = T>
--- a/server/crates/arbiter-macros/src/hashable.rs
+++ b/server/crates/arbiter-macros/src/hashable.rs
@@ -1,10 +1,8 @@
+use crate::utils::{HASHABLE_TRAIT_PATH, HMAC_DIGEST_PATH};
+
 use proc_macro2::{Span, TokenStream, TokenTree};
 use quote::quote;
-use syn::parse_quote;
-use syn::spanned::Spanned;
-use syn::{DataStruct, DeriveInput, Fields, Generics, Index};
-
-use crate::utils::{HASHABLE_TRAIT_PATH, HMAC_DIGEST_PATH};
+use syn::{DataStruct, DeriveInput, Fields, Generics, Index, parse_quote, spanned::Spanned};

 pub(crate) fn derive(input: &DeriveInput) -> TokenStream {
    match &input.data {
--- a/server/crates/arbiter-macros/src/utils.rs
+++ b/server/crates/arbiter-macros/src/utils.rs
@@ -1,7 +1,7 @@
-pub struct ToPath(pub &'static str);
+pub(crate) struct ToPath(pub(crate) &'static str);

 impl ToPath {
-    pub fn to_path(&self) -> syn::Path {
+    pub(crate) fn to_path(&self) -> syn::Path {
        syn::parse_str(self.0).expect("Invalid path")
    }
 }
@@ -15,5 +15,5 @@ macro_rules! ensure_path {
    }};
 }

-pub const HASHABLE_TRAIT_PATH: ToPath = ensure_path!(::arbiter_crypto::hashing::Hashable);
-pub const HMAC_DIGEST_PATH: ToPath = ensure_path!(::arbiter_crypto::hashing::Digest);
+pub(crate) const HASHABLE_TRAIT_PATH: ToPath = ensure_path!(::arbiter_crypto::hashing::Hashable);
+pub(crate) const HMAC_DIGEST_PATH: ToPath = ensure_path!(::arbiter_crypto::hashing::Digest);
--- a/server/crates/arbiter-proto/src/transport.rs
+++ b/server/crates/arbiter-proto/src/transport.rs
@@ -54,10 +54,9 @@
 //!   as a closed outbound channel.
 //! - [`Bi::recv`] returns `None` when the underlying transport closes.
 //! - Message translation is intentionally out of scope for this module.
-
-use std::marker::PhantomData;
-
 use async_trait::async_trait;
+use kameo::{error::Infallible, prelude::*};
+use std::marker::PhantomData;

 /// Errors returned by transport adapters implementing [`Bi`].
 #[derive(thiserror::Error, Debug)]
@@ -106,6 +105,36 @@ pub trait Receiver<Inbound>: Send + Sync {
 /// any built-in correlation mechanism between inbound and outbound items.
 pub trait Bi<Inbound, Outbound>: Sender<Outbound> + Receiver<Inbound> + Send + Sync {}

+#[async_trait]
+impl<T, Outbound> Sender<Outbound> for &mut T
+where
+    T: Sender<Outbound> + ?Sized,
+    Outbound: Send + 'static,
+{
+    async fn send(&mut self, item: Outbound) -> Result<(), Error> {
+        (**self).send(item).await
+    }
+}
+
+#[async_trait]
+impl<T, Inbound> Receiver<Inbound> for &mut T
+where
+    T: Receiver<Inbound> + ?Sized,
+    Inbound: Send + 'static,
+{
+    async fn recv(&mut self) -> Option<Inbound> {
+        (**self).recv().await
+    }
+}
+
+impl<T, Inbound, Outbound> Bi<Inbound, Outbound> for &mut T
+where
+    T: Bi<Inbound, Outbound> + ?Sized,
+    Inbound: Send + 'static,
+    Outbound: Send + 'static,
+{
+}
+
 pub trait SplittableBi<Inbound, Outbound>: Bi<Inbound, Outbound> {
    type Sender: Sender<Outbound>;
    type Receiver: Receiver<Inbound>;
@@ -161,3 +190,29 @@ where
 }

 pub mod grpc;
+
+#[derive(thiserror::Error, Debug)]
+pub enum ForwardError<I> {
+    #[error("Transport error: {0}")]
+    Transport(#[from] Error),
+    #[error("Actor delivery error: {0}")]
+    Actor(SendError<I>),
+}
+
+pub async fn forward_to_actor<Transport, Inbound, Outbound, Handler>(
+    transport: &mut Transport,
+    actor: &ActorRef<Handler>,
+) -> Result<(), ForwardError<Inbound>>
+where
+    Transport: Bi<Inbound, <Outbound as Reply>::Ok>,
+    Handler: Actor + Message<Inbound, Reply = Outbound>,
+    Inbound: Send + 'static,
+    Outbound: Send + 'static + Reply<Error = Infallible>, // `Infallible` to enforce contract that `Outbound` carries handler-level error
+{
+    while let Some(request) = transport.recv().await {
+        let resp = actor.ask(request).await.map_err(ForwardError::Actor)?;
+        transport.send(resp).await?
+    }
+
+    Err(Error::ChannelClosed.into())
+}
--- a/server/crates/arbiter-proto/src/transport/grpc.rs
+++ b/server/crates/arbiter-proto/src/transport/grpc.rs
@@ -1,10 +1,10 @@
+use super::{Bi, Receiver, Sender};
+
 use async_trait::async_trait;
 use futures::StreamExt;
 use tokio::sync::mpsc;
 use tokio_stream::wrappers::ReceiverStream;

-use super::{Bi, Receiver, Sender};
-
 pub struct GrpcSender<Outbound> {
    tx: mpsc::Sender<Result<Outbound, tonic::Status>>,
 }
--- a/server/crates/arbiter-proto/src/url.rs
+++ b/server/crates/arbiter-proto/src/url.rs
@@ -1,7 +1,6 @@
-use std::fmt::Display;
-
 use base64::{Engine as _, prelude::BASE64_URL_SAFE};
 use rustls_pki_types::CertificateDer;
+use std::fmt::Display;

 const ARBITER_URL_SCHEME: &str = "arbiter";
 const CERT_QUERY_KEY: &str = "cert";
--- a/server/crates/arbiter-server/Cargo.toml
+++ b/server/crates/arbiter-server/Cargo.toml
@@ -59,6 +59,7 @@ ml-dsa.workspace = true
 ed25519-dalek.workspace = true
 x25519-dalek.workspace = true
 k256.workspace = true
+kameo_actors.workspace = true

 [dev-dependencies]
 insta = "1.47.2"
--- a/server/crates/arbiter-server/migrations/2026-02-14-171124-0000_init/up.sql
+++ b/server/crates/arbiter-server/migrations/2026-02-14-171124-0000_init/up.sql
@@ -45,13 +45,11 @@ insert into arbiter_settings (id) values (1) on conflict do nothing;

 create table if not exists useragent_client (
    id integer not null primary key,
-    nonce integer not null default(1), -- used for auth challenge
    public_key blob not null,
-    key_type integer not null default(1),
    created_at integer not null default(unixepoch ('now')),
    updated_at integer not null default(unixepoch ('now'))
 ) STRICT;
-create unique index if not exists uniq_useragent_client_public_key on useragent_client (public_key, key_type);
+create unique index if not exists uniq_useragent_client_public_key on useragent_client (public_key);

 create table if not exists client_metadata (
    id integer not null primary key,
@@ -73,7 +71,6 @@ create unique index if not exists uniq_metadata_binding_client on client_metadat

 create table if not exists program_client (
    id integer not null primary key,
-    nonce integer not null default(1), -- used for auth challenge
    public_key blob not null,
    metadata_id integer not null references client_metadata (id) on delete cascade,
    created_at integer not null default(unixepoch ('now')),
--- a/server/crates/arbiter-server/src/actors/bootstrap.rs
+++ b/server/crates/arbiter-server/src/actors/bootstrap.rs
@@ -1,13 +1,13 @@
+use crate::db::{self, DatabasePool, schema};
 use arbiter_proto::{BOOTSTRAP_PATH, home_path};
+
 use diesel::QueryDsl;
 use diesel_async::RunQueryDsl;
 use kameo::{Actor, messages};
-
 use rand::{RngExt, distr::Alphanumeric, make_rng, rngs::StdRng};
 use subtle::ConstantTimeEq as _;
 use thiserror::Error;

-use crate::db::{self, DatabasePool, schema};
 const TOKEN_LENGTH: usize = 64;

 pub async fn generate_token() -> Result<String, std::io::Error> {
--- a/server/crates/arbiter-server/src/actors/evm/mod.rs
+++ b/server/crates/arbiter-server/src/actors/evm/mod.rs
@@ -1,13 +1,5 @@
-use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
-use diesel::{
-    ExpressionMethods, OptionalExtension as _, QueryDsl, SelectableHelper as _, dsl::insert_into,
-};
-use diesel_async::RunQueryDsl;
-use kameo::{Actor, actor::ActorRef, messages};
-use rand::{SeedableRng, rng, rngs::StdRng};
-
 use crate::{
-    actors::keyholder::{CreateNew, Decrypt, KeyHolder},
+    actors::vault::{CreateNew, Decrypt, Vault},
    crypto::integrity,
    db::{
        DatabaseError, DatabasePool,
@@ -24,6 +16,14 @@ use crate::{
 };
 use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};

+use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
+use diesel::{
+    ExpressionMethods, OptionalExtension as _, QueryDsl, SelectableHelper as _, dsl::insert_into,
+};
+use diesel_async::RunQueryDsl;
+use kameo::{Actor, actor::ActorRef, messages};
+use rand::{SeedableRng, rng, rngs::StdRng};
+
 pub use crate::evm::safe_signer;

 #[derive(Debug, thiserror::Error)]
@@ -34,11 +34,11 @@ pub enum SignTransactionError {
    #[error("Database error: {0}")]
    Database(#[from] DatabaseError),

-    #[error("Keyholder error: {0}")]
-    Keyholder(#[from] crate::actors::keyholder::Error),
+    #[error("Vault error: {0}")]
+    Vault(#[from] crate::actors::vault::Error),

-    #[error("Keyholder mailbox error")]
-    KeyholderSend,
+    #[error("Vault mailbox error")]
+    VaultSend,

    #[error("Signing error: {0}")]
    Signing(#[from] alloy::signers::Error),
@@ -49,11 +49,11 @@ pub enum SignTransactionError {

 #[derive(Debug, thiserror::Error)]
 pub enum Error {
-    #[error("Keyholder error: {0}")]
-    Keyholder(#[from] crate::actors::keyholder::Error),
+    #[error("Vault error: {0}")]
+    Vault(#[from] crate::actors::vault::Error),

-    #[error("Keyholder mailbox error")]
-    KeyholderSend,
+    #[error("Vault mailbox error")]
+    VaultSend,

    #[error("Database error: {0}")]
    Database(#[from] DatabaseError),
@@ -64,20 +64,20 @@ pub enum Error {

 #[derive(Actor)]
 pub struct EvmActor {
-    pub keyholder: ActorRef<KeyHolder>,
+    pub vault: ActorRef<Vault>,
    pub db: DatabasePool,
    pub rng: StdRng,
    pub engine: evm::Engine,
 }

 impl EvmActor {
-    pub fn new(keyholder: ActorRef<KeyHolder>, db: DatabasePool) -> Self {
+    pub fn new(vault: ActorRef<Vault>, db: DatabasePool) -> Self {
        // is it safe to seed rng from system once?
        // todo: audit
        let rng = StdRng::from_rng(&mut rng());
-        let engine = evm::Engine::new(db.clone(), keyholder.clone());
+        let engine = evm::Engine::new(db.clone(), vault.clone());
        Self {
-            keyholder,
+            vault,
            db,
            rng,
            engine,
@@ -94,10 +94,10 @@ impl EvmActor {
        let plaintext = key_cell.read_inline(|reader| SafeCell::new(reader.to_vec()));

        let aead_id: i32 = self
-            .keyholder
+            .vault
            .ask(CreateNew { plaintext })
            .await
-            .map_err(|_| Error::KeyholderSend)?;
+            .map_err(|_| Error::VaultSend)?;

        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
        let wallet_id = insert_into(schema::evm_wallet::table)
@@ -160,7 +160,7 @@ impl EvmActor {
    #[message]
    pub async fn useragent_delete_grant(&mut self, _grant_id: i32) -> Result<(), Error> {
        // let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
-        // let keyholder = self.keyholder.clone();
+        // let vault = self.vault.clone();

        // diesel_async::AsyncConnection::transaction(&mut conn, |conn| {
        //     Box::pin(async move {
@@ -254,12 +254,12 @@ impl EvmActor {
        drop(conn);

        let raw_key: SafeCell<Vec<u8>> = self
-            .keyholder
+            .vault
            .ask(Decrypt {
                aead_id: wallet.aead_encrypted_id,
            })
            .await
-            .map_err(|_| SignTransactionError::KeyholderSend)?;
+            .map_err(|_| SignTransactionError::VaultSend)?;

        let signer = safe_signer::SafeSigner::from_cell(raw_key)?;

--- a/server/crates/arbiter-server/src/actors/flow_coordinator/client_connect_approval.rs
+++ b/server/crates/arbiter-server/src/actors/flow_coordinator/client_connect_approval.rs
@@ -1,16 +1,17 @@
-use std::ops::ControlFlow;
+use crate::{
+    actors::flow_coordinator::ApprovalError,
+    peers::{
+        client::ClientProfile,
+        user_agent::{UserAgentSession, session::BeginNewClientApproval},
+    },
+};

 use kameo::{
    Actor, messages,
    prelude::{ActorId, ActorRef, ActorStopReason, Context, WeakActorRef},
    reply::ReplySender,
 };
-
-use crate::actors::{
-    client::ClientProfile,
-    flow_coordinator::ApprovalError,
-    user_agent::{UserAgentSession, session::BeginNewClientApproval},
-};
+use std::ops::ControlFlow;

 pub struct Args {
    pub client: ClientProfile,
--- a/server/crates/arbiter-server/src/actors/flow_coordinator/mod.rs
+++ b/server/crates/arbiter-server/src/actors/flow_coordinator/mod.rs
@@ -1,4 +1,10 @@
-use std::{collections::HashMap, ops::ControlFlow};
+use crate::{
+    actors::{
+        flow_coordinator::client_connect_approval::ClientApprovalController,
+        useragent_registry::{GetConnected, UserAgentRegistry},
+    },
+    peers::client::{ClientProfile, session::ClientSession},
+};

 use kameo::{
    Actor,
@@ -7,20 +13,23 @@ use kameo::{
    prelude::{ActorStopReason, Context, WeakActorRef},
    reply::DelegatedReply,
 };
+use std::{collections::HashMap, ops::ControlFlow};
 use tracing::info;

-use crate::actors::{
-    client::{ClientProfile, session::ClientSession},
-    flow_coordinator::client_connect_approval::ClientApprovalController,
-    user_agent::session::UserAgentSession,
-};
-
 pub mod client_connect_approval;

-#[derive(Default)]
 pub struct FlowCoordinator {
-    pub user_agents: HashMap<ActorId, ActorRef<UserAgentSession>>,
    pub clients: HashMap<ActorId, ActorRef<ClientSession>>,
+    useragent_registry: ActorRef<UserAgentRegistry>,
+}
+
+impl FlowCoordinator {
+    pub fn new(useragent_registry: ActorRef<UserAgentRegistry>) -> Self {
+        Self {
+            clients: HashMap::default(),
+            useragent_registry,
+        }
+    }
 }

 impl Actor for FlowCoordinator {
@@ -38,13 +47,7 @@ impl Actor for FlowCoordinator {
        id: ActorId,
        _: ActorStopReason,
    ) -> Result<ControlFlow<ActorStopReason>, Self::Error> {
-        if self.user_agents.remove(&id).is_some() {
-            info!(
-                ?id,
-                actor = "FlowCoordinator",
-                event = "useragent.disconnected"
-            );
-        } else if self.clients.remove(&id).is_some() {
+        if self.clients.remove(&id).is_some() {
            info!(
                ?id,
                actor = "FlowCoordinator",
@@ -69,17 +72,6 @@ pub enum ApprovalError {

 #[messages]
 impl FlowCoordinator {
-    #[message(ctx)]
-    pub async fn register_user_agent(
-        &mut self,
-        actor: ActorRef<UserAgentSession>,
-        ctx: &mut Context<Self, ()>,
-    ) {
-        info!(id = %actor.id(), actor = "FlowCoordinator", event = "useragent.connected");
-        ctx.actor_ref().link(&actor).await;
-        self.user_agents.insert(actor.id(), actor);
-    }
-
    #[message(ctx)]
    pub async fn register_client(
        &mut self,
@@ -101,7 +93,14 @@ impl FlowCoordinator {
            unreachable!("Expected `request_client_approval` to have callback channel");
        };

-        let refs: Vec<_> = self.user_agents.values().cloned().collect();
+        let refs = match self.useragent_registry.ask(GetConnected).await {
+            Ok(refs) => refs,
+            Err(_) => {
+                reply_sender.send(Err(ApprovalError::NoUserAgentsConnected));
+                return reply;
+            }
+        };
+
        if refs.is_empty() {
            reply_sender.send(Err(ApprovalError::NoUserAgentsConnected));
            return reply;
--- a/server/crates/arbiter-server/src/actors/mod.rs
+++ b/server/crates/arbiter-server/src/actors/mod.rs
@@ -1,47 +1,59 @@
-use kameo::actor::{ActorRef, Spawn};
-use thiserror::Error;
-
 use crate::{
    actors::{
        bootstrap::Bootstrapper, evm::EvmActor, flow_coordinator::FlowCoordinator,
-        keyholder::KeyHolder,
+        useragent_registry::UserAgentRegistry, vault::Vault,
    },
    db,
 };

+use kameo::actor::{ActorRef, Spawn};
+use kameo_actors::{DeliveryStrategy, message_bus::MessageBus};
+use thiserror::Error;
+
 pub mod bootstrap;
-pub mod client;
-mod evm;
+pub mod evm;
 pub mod flow_coordinator;
-pub mod keyholder;
-pub mod user_agent;
+pub mod useragent_registry;
+pub mod vault;

 #[derive(Error, Debug)]
 pub enum SpawnError {
    #[error("Failed to spawn Bootstrapper actor")]
    Bootstrapper(#[from] bootstrap::Error),

-    #[error("Failed to spawn KeyHolder actor")]
-    KeyHolder(#[from] keyholder::Error),
+    #[error("Failed to spawn Vault actor")]
+    Vault(#[from] vault::Error),
 }

 /// Long-lived actors that are shared across all connections and handle global state and operations
 #[derive(Clone)]
 pub struct GlobalActors {
-    pub key_holder: ActorRef<KeyHolder>,
+    pub vault: ActorRef<Vault>,
    pub bootstrapper: ActorRef<Bootstrapper>,
    pub flow_coordinator: ActorRef<FlowCoordinator>,
+    pub useragent_registry: ActorRef<UserAgentRegistry>,
    pub evm: ActorRef<EvmActor>,
+    pub events: ActorRef<MessageBus>,
 }

 impl GlobalActors {
+    pub fn spawn_message_bus() -> ActorRef<MessageBus> {
+        MessageBus::spawn(MessageBus::new(DeliveryStrategy::Guaranteed))
+    }
+
    pub async fn spawn(db: db::DatabasePool) -> Result<Self, SpawnError> {
-        let key_holder = KeyHolder::spawn(KeyHolder::new(db.clone()).await?);
+        let message_bus = Self::spawn_message_bus();
+        let key_holder = Vault::spawn(Vault::new(db.clone(), message_bus.clone()).await?);
+        let useragent_registry = UserAgentRegistry::spawn(UserAgentRegistry::default());
        Ok(Self {
            bootstrapper: Bootstrapper::spawn(Bootstrapper::new(&db).await?),
            evm: EvmActor::spawn(EvmActor::new(key_holder.clone(), db)),
-            key_holder,
-            flow_coordinator: FlowCoordinator::spawn(FlowCoordinator::default()),
+            vault: key_holder,
+            flow_coordinator: FlowCoordinator::spawn(FlowCoordinator::new(
+                useragent_registry.clone(),
+            )),
+            useragent_registry,
+            events: message_bus,
        })
    }
 }
--- a/server/crates/arbiter-server/src/actors/user_agent/auth/state.rs
+++ b/server/crates/arbiter-server/src/actors/user_agent/auth/state.rs
@@ -1,318 +0,0 @@
-use arbiter_crypto::authn::{self, USERAGENT_CONTEXT};
-use arbiter_proto::transport::Bi;
-use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl, update};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::actor::ActorRef;
-use tracing::error;
-
-use super::Error;
-use crate::{
-    actors::{
-        bootstrap::ConsumeToken,
-        keyholder::KeyHolder,
-        user_agent::{UserAgentConnection, UserAgentCredentials, auth::Outbound},
-    },
-    crypto::integrity,
-    db::{DatabasePool, schema::useragent_client},
-};
-
-pub struct ChallengeRequest {
-    pub pubkey: authn::PublicKey,
-}
-
-pub struct BootstrapAuthRequest {
-    pub pubkey: authn::PublicKey,
-    pub token: String,
-}
-
-pub struct ChallengeContext {
-    pub challenge_nonce: i32,
-    pub key: authn::PublicKey,
-}
-
-pub struct ChallengeSolution {
-    pub solution: Vec<u8>,
-}
-
-smlang::statemachine!(
-    name: Auth,
-    custom_error: true,
-    transitions: {
-        *Init + AuthRequest(ChallengeRequest) / async prepare_challenge = SentChallenge(ChallengeContext),
-        Init + BootstrapAuthRequest(BootstrapAuthRequest) / async verify_bootstrap_token = AuthOk(authn::PublicKey),
-        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) / async verify_solution = AuthOk(authn::PublicKey),
-    }
-);
-
-/// Returns the current nonce, ready to use for the challenge nonce.
-async fn get_current_nonce_and_id(
-    db: &DatabasePool,
-    key: &authn::PublicKey,
-) -> Result<(i32, i32), Error> {
-    let mut db_conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::internal("Database unavailable")
-    })?;
-    db_conn
-        .exclusive_transaction(|conn| {
-            Box::pin(async move {
-                useragent_client::table
-                    .filter(useragent_client::public_key.eq(key.to_bytes()))
-                    .select((useragent_client::id, useragent_client::nonce))
-                    .first::<(i32, i32)>(conn)
-                    .await
-            })
-        })
-        .await
-        .optional()
-        .map_err(|e| {
-            error!(error = ?e, "Database error");
-            Error::internal("Database operation failed")
-        })?
-        .ok_or_else(|| {
-            error!(?key, "Public key not found in database");
-            Error::UnregisteredPublicKey
-        })
-}
-
-async fn verify_integrity(
-    db: &DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
-    pubkey: &authn::PublicKey,
-) -> Result<(), Error> {
-    let mut db_conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::internal("Database unavailable")
-    })?;
-
-    let (id, nonce) = get_current_nonce_and_id(db, pubkey).await?;
-
-    let _result = integrity::verify_entity(
-        &mut db_conn,
-        keyholder,
-        &UserAgentCredentials {
-            pubkey: pubkey.clone(),
-            nonce,
-        },
-        id,
-    )
-    .await
-    .map_err(|e| {
-        error!(?e, "Integrity verification failed");
-        Error::internal("Integrity verification failed")
-    })?;
-
-    Ok(())
-}
-
-async fn create_nonce(
-    db: &DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
-    pubkey: &authn::PublicKey,
-) -> Result<i32, Error> {
-    let mut db_conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::internal("Database unavailable")
-    })?;
-    let new_nonce = db_conn
-        .exclusive_transaction(|conn| {
-            Box::pin(async move {
-                let (id, new_nonce): (i32, i32) = update(useragent_client::table)
-                    .filter(useragent_client::public_key.eq(pubkey.to_bytes()))
-                    .set(useragent_client::nonce.eq(useragent_client::nonce + 1))
-                    .returning((useragent_client::id, useragent_client::nonce))
-                    .get_result(conn)
-                    .await
-                    .map_err(|e| {
-                        error!(error = ?e, "Database error");
-                        Error::internal("Database operation failed")
-                    })?;
-
-                integrity::sign_entity(
-                    conn,
-                    keyholder,
-                    &UserAgentCredentials {
-                        pubkey: pubkey.clone(),
-                        nonce: new_nonce,
-                    },
-                    id,
-                )
-                .await
-                .map_err(|e| {
-                    error!(?e, "Integrity signature update failed");
-                    Error::internal("Database error")
-                })?;
-
-                Result::<_, Error>::Ok(new_nonce)
-            })
-        })
-        .await?;
-    Ok(new_nonce)
-}
-
-async fn register_key(
-    db: &DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
-    pubkey: &authn::PublicKey,
-) -> Result<(), Error> {
-    let pubkey_bytes = pubkey.to_bytes();
-    let mut conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::internal("Database unavailable")
-    })?;
-
-    conn.transaction(|conn| {
-        Box::pin(async move {
-            const NONCE_START: i32 = 1;
-
-            let id: i32 = diesel::insert_into(useragent_client::table)
-                .values((
-                    useragent_client::public_key.eq(pubkey_bytes),
-                    useragent_client::nonce.eq(NONCE_START),
-                ))
-                .returning(useragent_client::id)
-                .get_result(conn)
-                .await
-                .map_err(|e| {
-                    error!(error = ?e, "Database error");
-                    Error::internal("Database operation failed")
-                })?;
-
-            let entity = UserAgentCredentials {
-                pubkey: pubkey.clone(),
-                nonce: NONCE_START,
-            };
-
-            integrity::sign_entity(conn, keyholder, &entity, id)
-                .await
-                .map_err(|e| {
-                    error!(error = ?e, "Failed to sign integrity tag for new user-agent key");
-                    Error::internal("Failed to register public key")
-                })?;
-
-            Result::<_, Error>::Ok(())
-        })
-    })
-    .await?;
-
-    Ok(())
-}
-
-pub struct AuthContext<'a, T> {
-    pub(super) conn: &'a mut UserAgentConnection,
-    pub(super) transport: T,
-}
-
-impl<'a, T> AuthContext<'a, T> {
-    pub fn new(conn: &'a mut UserAgentConnection, transport: T) -> Self {
-        Self { conn, transport }
-    }
-}
-
-impl<T> AuthStateMachineContext for AuthContext<'_, T>
-where
-    T: Bi<super::Inbound, Result<super::Outbound, Error>> + Send,
-{
-    type Error = Error;
-
-    async fn prepare_challenge(
-        &mut self,
-        ChallengeRequest { pubkey }: ChallengeRequest,
-    ) -> Result<ChallengeContext, Self::Error> {
-        verify_integrity(&self.conn.db, &self.conn.actors.key_holder, &pubkey).await?;
-
-        let nonce = create_nonce(&self.conn.db, &self.conn.actors.key_holder, &pubkey).await?;
-
-        self.transport
-            .send(Ok(Outbound::AuthChallenge { nonce }))
-            .await
-            .map_err(|e| {
-                error!(?e, "Failed to send auth challenge");
-                Error::Transport
-            })?;
-
-        Ok(ChallengeContext {
-            challenge_nonce: nonce,
-            key: pubkey,
-        })
-    }
-
-    #[allow(missing_docs)]
-    #[allow(clippy::result_unit_err)]
-    async fn verify_bootstrap_token(
-        &mut self,
-        BootstrapAuthRequest { pubkey, token }: BootstrapAuthRequest,
-    ) -> Result<authn::PublicKey, Self::Error> {
-        let token_ok: bool = self
-            .conn
-            .actors
-            .bootstrapper
-            .ask(ConsumeToken {
-                token: token.clone(),
-            })
-            .await
-            .map_err(|e| {
-                error!(?e, "Failed to consume bootstrap token");
-                Error::internal("Failed to consume bootstrap token")
-            })?;
-
-        if !token_ok {
-            error!("Invalid bootstrap token provided");
-            return Err(Error::InvalidBootstrapToken);
-        }
-
-        match token_ok {
-            true => {
-                register_key(&self.conn.db, &self.conn.actors.key_holder, &pubkey).await?;
-                self.transport
-                    .send(Ok(Outbound::AuthSuccess))
-                    .await
-                    .map_err(|_| Error::Transport)?;
-                Ok(pubkey)
-            }
-            false => {
-                error!("Invalid bootstrap token provided");
-                self.transport
-                    .send(Err(Error::InvalidBootstrapToken))
-                    .await
-                    .map_err(|_| Error::Transport)?;
-                Err(Error::InvalidBootstrapToken)
-            }
-        }
-    }
-
-    #[allow(missing_docs)]
-    #[allow(clippy::unused_unit)]
-    async fn verify_solution(
-        &mut self,
-        ChallengeContext {
-            challenge_nonce,
-            key,
-        }: &ChallengeContext,
-        ChallengeSolution { solution }: ChallengeSolution,
-    ) -> Result<authn::PublicKey, Self::Error> {
-        let signature = authn::Signature::try_from(solution.as_slice()).map_err(|_| {
-            error!("Failed to decode signature in challenge solution");
-            Error::InvalidChallengeSolution
-        })?;
-
-        let valid = key.verify(*challenge_nonce, USERAGENT_CONTEXT, &signature);
-
-        match valid {
-            true => {
-                self.transport
-                    .send(Ok(Outbound::AuthSuccess))
-                    .await
-                    .map_err(|_| Error::Transport)?;
-                Ok(key.clone())
-            }
-            false => {
-                self.transport
-                    .send(Err(Error::InvalidChallengeSolution))
-                    .await
-                    .map_err(|_| Error::Transport)?;
-                Err(Error::InvalidChallengeSolution)
-            }
-        }
-    }
-}
--- a/server/crates/arbiter-server/src/actors/user_agent/mod.rs
+++ b/server/crates/arbiter-server/src/actors/user_agent/mod.rs
@@ -1,40 +0,0 @@
-use crate::{
-    actors::{GlobalActors, client::ClientProfile},
-    crypto::integrity::Integrable,
-    db,
-};
-use arbiter_crypto::authn;
-
-#[derive(Debug, arbiter_macros::Hashable)]
-pub struct UserAgentCredentials {
-    pub pubkey: authn::PublicKey,
-    pub nonce: i32,
-}
-
-impl Integrable for UserAgentCredentials {
-    const KIND: &'static str = "useragent_credentials";
-}
-
-// Messages, sent by user agent to connection client without having a request
-#[derive(Debug)]
-pub enum OutOfBand {
-    ClientConnectionRequest { profile: ClientProfile },
-    ClientConnectionCancel { pubkey: authn::PublicKey },
-}
-
-pub struct UserAgentConnection {
-    pub(crate) db: db::DatabasePool,
-    pub(crate) actors: GlobalActors,
-}
-
-impl UserAgentConnection {
-    pub fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
-        Self { db, actors }
-    }
-}
-
-pub mod auth;
-pub mod session;
-
-pub use auth::authenticate;
-pub use session::UserAgentSession;
--- a/server/crates/arbiter-server/src/actors/user_agent/session/connection.rs
+++ b/server/crates/arbiter-server/src/actors/user_agent/session/connection.rs
@@ -1,524 +0,0 @@
-use std::sync::Mutex;
-
-use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
-use arbiter_crypto::{
-    authn,
-    safecell::{SafeCell, SafeCellHandle as _},
-};
-use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
-use diesel::{ExpressionMethods as _, QueryDsl as _, SelectableHelper};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::error::SendError;
-use kameo::messages;
-use kameo::prelude::Context;
-use tracing::{error, info};
-use x25519_dalek::{EphemeralSecret, PublicKey};
-
-use crate::actors::flow_coordinator::client_connect_approval::ClientApprovalAnswer;
-use crate::actors::keyholder::KeyHolderState;
-use crate::actors::user_agent::session::Error;
-use crate::actors::{
-    evm::{
-        ClientSignTransaction, Generate, ListWallets, SignTransactionError as EvmSignError,
-        UseragentCreateGrant, UseragentListGrants,
-    },
-    keyholder::{self, Bootstrap, TryUnseal},
-    user_agent::session::{
-        UserAgentSession,
-        state::{UnsealContext, UserAgentEvents, UserAgentStates},
-    },
-};
-use crate::db::models::{
-    EvmWalletAccess, NewEvmWalletAccess, ProgramClient, ProgramClientMetadata,
-};
-use crate::evm::policies::{Grant, SpecificGrant};
-
-impl UserAgentSession {
-    fn take_unseal_secret(&mut self) -> Result<(EphemeralSecret, PublicKey), Error> {
-        let UserAgentStates::WaitingForUnsealKey(unseal_context) = self.state.state() else {
-            error!("Received encrypted key in invalid state");
-            return Err(Error::internal("Invalid state for unseal encrypted key"));
-        };
-
-        let ephemeral_secret = {
-            #[allow(
-                clippy::unwrap_used,
-                reason = "Mutex poison is unrecoverable and should panic"
-            )]
-            let mut secret_lock = unseal_context.secret.lock().unwrap();
-            let secret = secret_lock.take();
-            match secret {
-                Some(secret) => secret,
-                None => {
-                    drop(secret_lock);
-                    error!("Ephemeral secret already taken");
-                    return Err(Error::internal("Ephemeral secret already taken"));
-                }
-            }
-        };
-
-        Ok((ephemeral_secret, unseal_context.client_public_key))
-    }
-
-    fn decrypt_client_key_material(
-        ephemeral_secret: EphemeralSecret,
-        client_public_key: PublicKey,
-        nonce: &[u8],
-        ciphertext: &[u8],
-        associated_data: &[u8],
-    ) -> Result<SafeCell<Vec<u8>>, ()> {
-        let nonce = XNonce::from_slice(nonce);
-
-        let shared_secret = ephemeral_secret.diffie_hellman(&client_public_key);
-        let cipher = XChaCha20Poly1305::new(shared_secret.as_bytes().into());
-
-        let mut key_buffer = SafeCell::new(ciphertext.to_vec());
-
-        let decryption_result = key_buffer.write_inline(|write_handle| {
-            cipher.decrypt_in_place(nonce, associated_data, write_handle)
-        });
-
-        match decryption_result {
-            Ok(_) => Ok(key_buffer),
-            Err(err) => {
-                error!(?err, "Failed to decrypt encrypted key material");
-                Err(())
-            }
-        }
-    }
-}
-
-pub struct UnsealStartResponse {
-    pub server_pubkey: PublicKey,
-}
-
-#[derive(Debug, Error)]
-pub enum UnsealError {
-    #[error("Invalid key provided for unsealing")]
-    InvalidKey,
-    #[error("Internal error during unsealing process")]
-    General(#[from] super::Error),
-}
-
-#[derive(Debug, Error)]
-pub enum BootstrapError {
-    #[error("Invalid key provided for bootstrapping")]
-    InvalidKey,
-    #[error("Vault is already bootstrapped")]
-    AlreadyBootstrapped,
-
-    #[error("Internal error during bootstrapping process")]
-    General(#[from] super::Error),
-}
-
-#[derive(Debug, Error)]
-pub enum SignTransactionError {
-    #[error("Policy evaluation failed")]
-    Vet(#[from] crate::evm::VetError),
-
-    #[error("Internal signing error")]
-    Internal,
-}
-
-#[derive(Debug, Error)]
-pub enum GrantMutationError {
-    #[error("Vault is sealed")]
-    VaultSealed,
-
-    #[error("Internal grant mutation error")]
-    Internal,
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub async fn handle_unseal_request(
-        &mut self,
-        client_pubkey: x25519_dalek::PublicKey,
-    ) -> Result<UnsealStartResponse, Error> {
-        let secret = EphemeralSecret::random();
-        let public_key = PublicKey::from(&secret);
-
-        self.transition(UserAgentEvents::UnsealRequest(UnsealContext {
-            secret: Mutex::new(Some(secret)),
-            client_public_key: client_pubkey,
-        }))?;
-
-        Ok(UnsealStartResponse {
-            server_pubkey: public_key,
-        })
-    }
-
-    #[message]
-    pub async fn handle_unseal_encrypted_key(
-        &mut self,
-        nonce: Vec<u8>,
-        ciphertext: Vec<u8>,
-        associated_data: Vec<u8>,
-    ) -> Result<(), UnsealError> {
-        let (ephemeral_secret, client_public_key) = match self.take_unseal_secret() {
-            Ok(values) => values,
-            Err(Error::State) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(UnsealError::InvalidKey);
-            }
-            Err(_err) => {
-                return Err(Error::internal("Failed to take unseal secret").into());
-            }
-        };
-
-        let seal_key_buffer = match Self::decrypt_client_key_material(
-            ephemeral_secret,
-            client_public_key,
-            &nonce,
-            &ciphertext,
-            &associated_data,
-        ) {
-            Ok(buffer) => buffer,
-            Err(()) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(UnsealError::InvalidKey);
-            }
-        };
-
-        match self
-            .props
-            .actors
-            .key_holder
-            .ask(TryUnseal {
-                seal_key_raw: seal_key_buffer,
-            })
-            .await
-        {
-            Ok(_) => {
-                info!("Successfully unsealed key with client-provided key");
-                self.transition(UserAgentEvents::ReceivedValidKey)?;
-                Ok(())
-            }
-            Err(SendError::HandlerError(keyholder::Error::InvalidKey)) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(UnsealError::InvalidKey)
-            }
-            Err(SendError::HandlerError(err)) => {
-                error!(?err, "Keyholder failed to unseal key");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(UnsealError::InvalidKey)
-            }
-            Err(err) => {
-                error!(?err, "Failed to send unseal request to keyholder");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(Error::internal("Vault actor error").into())
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_bootstrap_encrypted_key(
-        &mut self,
-        nonce: Vec<u8>,
-        ciphertext: Vec<u8>,
-        associated_data: Vec<u8>,
-    ) -> Result<(), BootstrapError> {
-        let (ephemeral_secret, client_public_key) = match self.take_unseal_secret() {
-            Ok(values) => values,
-            Err(Error::State) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(BootstrapError::InvalidKey);
-            }
-            Err(err) => return Err(err.into()),
-        };
-
-        let seal_key_buffer = match Self::decrypt_client_key_material(
-            ephemeral_secret,
-            client_public_key,
-            &nonce,
-            &ciphertext,
-            &associated_data,
-        ) {
-            Ok(buffer) => buffer,
-            Err(()) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                return Err(BootstrapError::InvalidKey);
-            }
-        };
-
-        match self
-            .props
-            .actors
-            .key_holder
-            .ask(Bootstrap {
-                seal_key_raw: seal_key_buffer,
-            })
-            .await
-        {
-            Ok(_) => {
-                info!("Successfully bootstrapped vault with client-provided key");
-                self.transition(UserAgentEvents::ReceivedValidKey)?;
-                Ok(())
-            }
-            Err(SendError::HandlerError(keyholder::Error::AlreadyBootstrapped)) => {
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::AlreadyBootstrapped)
-            }
-            Err(SendError::HandlerError(err)) => {
-                error!(?err, "Keyholder failed to bootstrap vault");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::InvalidKey)
-            }
-            Err(err) => {
-                error!(?err, "Failed to send bootstrap request to keyholder");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Err(BootstrapError::General(Error::internal(
-                    "Vault actor error",
-                )))
-            }
-        }
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<KeyHolderState, Error> {
-        use crate::actors::keyholder::GetState;
-
-        let vault_state = match self.props.actors.key_holder.ask(GetState {}).await {
-            Ok(state) => state,
-            Err(err) => {
-                error!(?err, actor = "useragent", "keyholder.query.failed");
-                return Err(Error::internal("Vault is in broken state"));
-            }
-        };
-
-        Ok(vault_state)
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub(crate) async fn handle_evm_wallet_create(&mut self) -> Result<(i32, Address), Error> {
-        match self.props.actors.evm.ask(Generate {}).await {
-            Ok(address) => Ok(address),
-            Err(SendError::HandlerError(err)) => Err(Error::internal(format!(
-                "EVM wallet generation failed: {err}"
-            ))),
-            Err(err) => {
-                error!(?err, "EVM actor unreachable during wallet create");
-                Err(Error::internal("EVM actor unreachable"))
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_evm_wallet_list(&mut self) -> Result<Vec<(i32, Address)>, Error> {
-        match self.props.actors.evm.ask(ListWallets {}).await {
-            Ok(wallets) => Ok(wallets),
-            Err(err) => {
-                error!(?err, "EVM wallet list failed");
-                Err(Error::internal("Failed to list EVM wallets"))
-            }
-        }
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message]
-    pub(crate) async fn handle_grant_list(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
-        match self.props.actors.evm.ask(UseragentListGrants {}).await {
-            Ok(grants) => Ok(grants),
-            Err(err) => {
-                error!(?err, "EVM grant list failed");
-                Err(Error::internal("Failed to list EVM grants"))
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_grant_create(
-        &mut self,
-        basic: crate::evm::policies::SharedGrantSettings,
-        grant: crate::evm::policies::SpecificGrant,
-    ) -> Result<i32, GrantMutationError> {
-        match self
-            .props
-            .actors
-            .evm
-            .ask(UseragentCreateGrant { basic, grant })
-            .await
-        {
-            Ok(grant_id) => Ok(grant_id),
-            Err(err) => {
-                error!(?err, "EVM grant create failed");
-                Err(GrantMutationError::Internal)
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_grant_delete(
-        &mut self,
-        grant_id: i32,
-    ) -> Result<(), GrantMutationError> {
-        // match self
-        //     .props
-        //     .actors
-        //     .evm
-        //     .ask(UseragentDeleteGrant { grant_id })
-        //     .await
-        // {
-        //     Ok(()) => Ok(()),
-        //     Err(err) => {
-        //         error!(?err, "EVM grant delete failed");
-        //         Err(GrantMutationError::Internal)
-        //     }
-        // }
-       let _ = grant_id;
-        todo!()
-    }
-
-    #[message]
-    pub(crate) async fn handle_sign_transaction(
-        &mut self,
-        client_id: i32,
-        wallet_address: Address,
-        transaction: TxEip1559,
-    ) -> Result<Signature, SignTransactionError> {
-        match self
-            .props
-            .actors
-            .evm
-            .ask(ClientSignTransaction {
-                client_id,
-                wallet_address,
-                transaction,
-            })
-            .await
-        {
-            Ok(signature) => Ok(signature),
-            Err(SendError::HandlerError(EvmSignError::Vet(vet_error))) => {
-                Err(SignTransactionError::Vet(vet_error))
-            }
-            Err(err) => {
-                error!(?err, "EVM sign transaction failed in user-agent session");
-                Err(SignTransactionError::Internal)
-            }
-        }
-    }
-
-    #[message]
-    pub(crate) async fn handle_grant_evm_wallet_access(
-        &mut self,
-        entries: Vec<NewEvmWalletAccess>,
-    ) -> Result<(), Error> {
-        let mut conn = self.props.db.get().await?;
-        conn.transaction(|conn| {
-            Box::pin(async move {
-                use crate::db::schema::evm_wallet_access;
-
-                for entry in entries {
-                    diesel::insert_into(evm_wallet_access::table)
-                        .values(&entry)
-                        .on_conflict_do_nothing()
-                        .execute(conn)
-                        .await?;
-                }
-
-                Result::<_, Error>::Ok(())
-            })
-        })
-        .await?;
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_revoke_evm_wallet_access(
-        &mut self,
-        entries: Vec<i32>,
-    ) -> Result<(), Error> {
-        let mut conn = self.props.db.get().await?;
-        conn.transaction(|conn| {
-            Box::pin(async move {
-                use crate::db::schema::evm_wallet_access;
-                for entry in entries {
-                    diesel::delete(evm_wallet_access::table)
-                        .filter(evm_wallet_access::wallet_id.eq(entry))
-                        .execute(conn)
-                        .await?;
-                }
-
-                Result::<_, Error>::Ok(())
-            })
-        })
-        .await?;
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_list_wallet_access(
-        &mut self,
-    ) -> Result<Vec<EvmWalletAccess>, Error> {
-        let mut conn = self.props.db.get().await?;
-        use crate::db::schema::evm_wallet_access;
-        let access_entries = evm_wallet_access::table
-            .select(EvmWalletAccess::as_select())
-            .load::<_>(&mut conn)
-            .await?;
-        Ok(access_entries)
-    }
-}
-
-#[messages]
-impl UserAgentSession {
-    #[message(ctx)]
-    pub(crate) async fn handle_new_client_approve(
-        &mut self,
-        approved: bool,
-        pubkey: authn::PublicKey,
-        ctx: &mut Context<Self, Result<(), Error>>,
-    ) -> Result<(), Error> {
-        let pending_approval = match self.pending_client_approvals.remove(&pubkey.to_bytes()) {
-            Some(approval) => approval,
-            None => {
-                error!("Received client connection response for unknown client");
-                return Err(Error::internal("Unknown client in connection response"));
-            }
-        };
-
-        pending_approval
-            .controller
-            .tell(ClientApprovalAnswer { approved })
-            .await
-            .map_err(|err| {
-                error!(
-                    ?err,
-                    "Failed to send client approval response to controller"
-                );
-                Error::internal("Failed to send client approval response to controller")
-            })?;
-
-        ctx.actor_ref().unlink(&pending_approval.controller).await;
-
-        Ok(())
-    }
-
-    #[message]
-    pub(crate) async fn handle_sdk_client_list(
-        &mut self,
-    ) -> Result<Vec<(ProgramClient, ProgramClientMetadata)>, Error> {
-        use crate::db::schema::{client_metadata, program_client};
-        let mut conn = self.props.db.get().await?;
-
-        let clients = program_client::table
-            .inner_join(client_metadata::table)
-            .select((
-                ProgramClient::as_select(),
-                ProgramClientMetadata::as_select(),
-            ))
-            .load::<(ProgramClient, ProgramClientMetadata)>(&mut conn)
-            .await?;
-
-        Ok(clients)
-    }
-}
--- a/server/crates/arbiter-server/src/actors/user_agent/session/state.rs
+++ b/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)
-    }
-}
--- a/server/crates/arbiter-server/src/actors/useragent_registry.rs
+++ b/server/crates/arbiter-server/src/actors/useragent_registry.rs
@@ -0,0 +1,61 @@
+use crate::peers::user_agent::UserAgentSession;
+
+use kameo::{
+    Actor,
+    actor::{ActorId, ActorRef},
+    error::Infallible,
+    messages,
+    prelude::{ActorStopReason, Context, WeakActorRef},
+};
+use std::{collections::HashMap, ops::ControlFlow};
+use tracing::info;
+
+#[derive(Default)]
+pub struct UserAgentRegistry {
+    connected: HashMap<ActorId, ActorRef<UserAgentSession>>,
+}
+
+impl Actor for UserAgentRegistry {
+    type Args = Self;
+
+    type Error = Infallible;
+
+    async fn on_start(args: Self::Args, _: ActorRef<Self>) -> Result<Self, Self::Error> {
+        Ok(args)
+    }
+
+    async fn on_link_died(
+        &mut self,
+        _: WeakActorRef<Self>,
+        id: ActorId,
+        _: ActorStopReason,
+    ) -> Result<ControlFlow<ActorStopReason>, Self::Error> {
+        if self.connected.remove(&id).is_some() {
+            info!(
+                ?id,
+                actor = "UserAgentRegistry",
+                event = "useragent.disconnected"
+            );
+        }
+        Ok(ControlFlow::Continue(()))
+    }
+}
+
+#[messages]
+impl UserAgentRegistry {
+    #[message(ctx)]
+    pub async fn connect_useragent(
+        &mut self,
+        actor: ActorRef<UserAgentSession>,
+        ctx: &mut Context<Self, ()>,
+    ) {
+        info!(id = %actor.id(), actor = "UserAgentRegistry", event = "useragent.connected");
+        ctx.actor_ref().link(&actor).await;
+        self.connected.insert(actor.id(), actor);
+    }
+
+    #[message]
+    pub fn get_connected(&self) -> Vec<ActorRef<UserAgentSession>> {
+        self.connected.values().cloned().collect()
+    }
+}
--- a/server/crates/arbiter-server/src/actors/keyholder/mod.rs
+++ b/server/crates/arbiter-server/src/actors/keyholder/mod.rs
@@ -1,3 +1,17 @@
+use crate::{
+    crypto::{
+        KeyCell, derive_key,
+        encryption::v1::{self, Nonce},
+        integrity::v1::HmacSha256,
+    },
+    db::{
+        self,
+        models::{self, RootKeyHistory},
+        schema::{self},
+    },
+};
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+
 use chrono::Utc;
 use diesel::{
    ExpressionMethods as _, OptionalExtension, QueryDsl, SelectableHelper,
@@ -5,42 +19,31 @@ use diesel::{
 };
 use diesel_async::{AsyncConnection, RunQueryDsl};
 use hmac::{KeyInit as _, Mac as _};
-use kameo::{Actor, Reply, messages};
+use kameo::{Actor, Reply, actor::ActorRef, messages};
+use kameo_actors::message_bus::{MessageBus, Publish};
 use strum::{EnumDiscriminants, IntoDiscriminant};
 use tracing::{error, info};

-use crate::crypto::{
-    KeyCell, derive_key,
-    encryption::v1::{self, Nonce},
-    integrity::v1::HmacSha256,
-};
-use crate::db::{
-    self,
-    models::{self, RootKeyHistory},
-    schema::{self},
-};
-use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+pub mod events {

-#[derive(Default, EnumDiscriminants)]
-#[strum_discriminants(derive(Reply), vis(pub), name(KeyHolderState))]
-enum State {
-    #[default]
-    Unbootstrapped,
-    Sealed {
-        root_key_history_id: i32,
-    },
-    Unsealed {
-        root_key_history_id: i32,
-        root_key: KeyCell,
-    },
+    #[derive(Clone, Copy)]
+    pub struct Bootstrapped;
+
+    #[derive(Clone, Copy)]
+    pub struct Unsealed;
+
+    #[derive(Clone, Copy)]
+    pub struct VaultResealed;
 }

 #[derive(Debug, thiserror::Error)]
 pub enum Error {
-    #[error("Keyholder is already bootstrapped")]
+    #[error("Vault is already bootstrapped")]
    AlreadyBootstrapped,
-    #[error("Keyholder is not bootstrapped")]
+    #[error("Vault is not bootstrapped")]
    NotBootstrapped,
+    #[error("Vault is sealed")]
+    Sealed,
    #[error("Invalid key provided")]
    InvalidKey,

@@ -60,18 +63,35 @@ pub enum Error {
    BrokenDatabase,
 }

+struct Unsealed {
+    root_key_history_id: i32,
+    root_key: KeyCell,
+}
+
+#[derive(Default, EnumDiscriminants)]
+#[strum_discriminants(derive(Reply), vis(pub), name(VaultState))]
+enum State {
+    #[default]
+    Unbootstrapped,
+    Sealed {
+        root_key_history_id: i32,
+    },
+    Unsealed(Unsealed),
+}
+
 /// Manages vault root key and tracks current state of the vault (bootstrapped/unbootstrapped, sealed/unsealed).
 /// Provides API for encrypting and decrypting data using the vault root key.
 /// Abstraction over database to make sure nonces are never reused and encryption keys are never exposed in plaintext outside of this actor.
 #[derive(Actor)]
-pub struct KeyHolder {
+pub struct Vault {
    db: db::DatabasePool,
    state: State,
+    events: ActorRef<MessageBus>,
 }

 #[messages]
-impl KeyHolder {
-    pub async fn new(db: db::DatabasePool) -> Result<Self, Error> {
+impl Vault {
+    pub async fn new(db: db::DatabasePool, events: ActorRef<MessageBus>) -> Result<Self, Error> {
        let state = {
            let mut conn = db.get().await?;

@@ -89,10 +109,10 @@ impl KeyHolder {
            }
        };

-        Ok(Self { db, state })
+        Ok(Self { db, state, events })
    }

-    // Exclusive transaction to avoid race condtions if multiple keyholders write
+    // Exclusive transaction to avoid race condtions if multiple vaults write
    // additional layer of protection against nonce-reuse
    async fn get_new_nonce(pool: &db::DatabasePool, root_key_id: i32) -> Result<Nonce, Error> {
        let mut conn = pool.get().await?;
@@ -129,6 +149,14 @@ impl KeyHolder {
        Ok(nonce)
    }

+    fn expect_unsealed(state: &mut State) -> Result<&mut Unsealed, Error> {
+        match state {
+            State::Unsealed(unsealed) => Ok(unsealed),
+            State::Unbootstrapped => Err(Error::NotBootstrapped),
+            State::Sealed { .. } => Err(Error::Sealed),
+        }
+    }
+
    #[message]
    pub async fn bootstrap(&mut self, seal_key_raw: SafeCell<Vec<u8>>) -> Result<(), Error> {
        if !matches!(self.state, State::Unbootstrapped) {
@@ -181,12 +209,13 @@ impl KeyHolder {
            })
            .await?;

-        self.state = State::Unsealed {
+        self.state = State::Unsealed(Unsealed {
            root_key,
            root_key_history_id,
-        };
+        });

-        info!("Keyholder bootstrapped successfully");
+        info!("Vault bootstrapped successfully");
+        let _ = self.events.tell(Publish(events::Bootstrapped)).await;

        Ok(())
    }
@@ -233,24 +262,23 @@ impl KeyHolder {
                Error::InvalidKey
            })?;

-        self.state = State::Unsealed {
+        self.state = State::Unsealed(Unsealed {
            root_key_history_id: current_key.id,
            root_key: KeyCell::try_from(root_key).map_err(|err| {
                error!(?err, "Broken database: invalid encryption key size");
                Error::BrokenDatabase
            })?,
-        };
+        });

-        info!("Keyholder unsealed successfully");
+        info!("Vault unsealed successfully");
+        let _ = self.events.tell(Publish(events::Unsealed)).await;

        Ok(())
    }

    #[message]
    pub async fn decrypt(&mut self, aead_id: i32) -> Result<SafeCell<Vec<u8>>, Error> {
-        let State::Unsealed { root_key, .. } = &mut self.state else {
-            return Err(Error::NotBootstrapped);
-        };
+        let Unsealed { root_key, .. } = Self::expect_unsealed(&mut self.state)?;

        let row: models::AeadEncrypted = {
            let mut conn = self.db.get().await?;
@@ -278,14 +306,10 @@ impl KeyHolder {
    // Creates new `aead_encrypted` entry in the database and returns it's ID
    #[message]
    pub async fn create_new(&mut self, mut plaintext: SafeCell<Vec<u8>>) -> Result<i32, Error> {
-        let State::Unsealed {
+        let Unsealed {
            root_key,
            root_key_history_id,
-            ..
-        } = &mut self.state
-        else {
-            return Err(Error::NotBootstrapped);
-        };
+        } = Self::expect_unsealed(&mut self.state)?;

        // Order matters here - `get_new_nonce` acquires connection, so we need to call it before next acquire
        // Borrow checker note: &mut borrow a few lines above is disjoint from this field
@@ -315,19 +339,16 @@ impl KeyHolder {
    }

    #[message]
-    pub fn get_state(&self) -> KeyHolderState {
+    pub fn get_state(&self) -> VaultState {
        self.state.discriminant()
    }

    #[message]
    pub fn sign_integrity(&mut self, mac_input: Vec<u8>) -> Result<(i32, Vec<u8>), Error> {
-        let State::Unsealed {
+        let Unsealed {
            root_key,
            root_key_history_id,
-        } = &mut self.state
-        else {
-            return Err(Error::NotBootstrapped);
-        };
+        } = Self::expect_unsealed(&mut self.state)?;

        let mut hmac = root_key
            .0
@@ -349,13 +370,10 @@ impl KeyHolder {
        expected_mac: Vec<u8>,
        key_version: i32,
    ) -> Result<bool, Error> {
-        let State::Unsealed {
+        let Unsealed {
            root_key,
            root_key_history_id,
-        } = &mut self.state
-        else {
-            return Err(Error::NotBootstrapped);
-        };
+        } = Self::expect_unsealed(&mut self.state)?;

        if *root_key_history_id != key_version {
            return Ok(false);
@@ -374,17 +392,16 @@ impl KeyHolder {
    }

    #[message]
-    pub fn seal(&mut self) -> Result<(), Error> {
-        let State::Unsealed {
+    pub async fn seal(&mut self) -> Result<(), Error> {
+        let Unsealed {
            root_key_history_id,
            ..
-        } = &self.state
-        else {
-            return Err(Error::NotBootstrapped);
-        };
+        } = Self::expect_unsealed(&mut self.state)?;
+
        self.state = State::Sealed {
            root_key_history_id: *root_key_history_id,
        };
+        let _ = self.events.tell(Publish(events::VaultResealed)).await;
        Ok(())
    }
 }
@@ -395,13 +412,18 @@ mod tests {

    use diesel_async::RunQueryDsl;

-    use crate::db::{self};
+    use crate::{
+        actors::GlobalActors,
+        db::{self},
+    };
    use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};

    use super::*;

-    async fn bootstrapped_actor(db: &db::DatabasePool) -> KeyHolder {
-        let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    async fn bootstrapped_actor(db: &db::DatabasePool) -> Vault {
+        let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+            .await
+            .unwrap();
        let seal_key = SafeCell::new(b"test-seal-key".to_vec());
        actor.bootstrap(seal_key).await.unwrap();
        actor
@@ -413,17 +435,17 @@ 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");
--- a/server/crates/arbiter-server/src/context/mod.rs
+++ b/server/crates/arbiter-server/src/context/mod.rs
@@ -1,13 +1,12 @@
-use std::sync::Arc;
-
-use thiserror::Error;
-
 use crate::{
    actors::GlobalActors,
    context::tls::TlsManager,
    db::{self},
 };

+use std::sync::Arc;
+use thiserror::Error;
+
 pub mod tls;

 #[derive(Error, Debug)]
--- a/server/crates/arbiter-server/src/context/tls.rs
+++ b/server/crates/arbiter-server/src/context/tls.rs
@@ -1,17 +1,3 @@
-use std::{net::Ipv4Addr, string::FromUtf8Error};
-
-use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper as _};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-
-use pem::Pem;
-use rcgen::{
-    BasicConstraints, Certificate, CertificateParams, CertifiedIssuer, DistinguishedName, DnType,
-    IsCa, Issuer, KeyPair, KeyUsagePurpose, SanType,
-};
-use rustls::pki_types::pem::PemObject;
-use thiserror::Error;
-use tonic::transport::CertificateDer;
-
 use crate::db::{
    self,
    models::{NewTlsHistory, TlsHistory},
@@ -21,6 +7,18 @@ use crate::db::{
    },
 };

+use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper as _};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use pem::Pem;
+use rcgen::{
+    BasicConstraints, Certificate, CertificateParams, CertifiedIssuer, DistinguishedName, DnType,
+    IsCa, Issuer, KeyPair, KeyUsagePurpose, SanType,
+};
+use rustls::pki_types::pem::PemObject;
+use std::{net::Ipv4Addr, string::FromUtf8Error};
+use thiserror::Error;
+use tonic::transport::CertificateDer;
+
 const ENCODE_CONFIG: pem::EncodeConfig = {
    let line_ending = match cfg!(target_family = "windows") {
        true => pem::LineEnding::CRLF,
--- a/server/crates/arbiter-server/src/crypto/encryption/v1.rs
+++ b/server/crates/arbiter-server/src/crypto/encryption/v1.rs
@@ -1,5 +1,4 @@
 use argon2::password_hash::Salt as ArgonSalt;
-
 use rand::{
    Rng as _, SeedableRng,
    rngs::{StdRng, SysRng},
@@ -63,7 +62,7 @@ mod tests {
    use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};

    #[test]
-    pub fn derive_seal_key_deterministic() {
+    fn derive_seal_key_deterministic() {
        static PASSWORD: &[u8] = b"password";
        let password = SafeCell::new(PASSWORD.to_vec());
        let password2 = SafeCell::new(PASSWORD.to_vec());
@@ -79,7 +78,7 @@ mod tests {
    }

    #[test]
-    pub fn successful_derive() {
+    fn successful_derive() {
        static PASSWORD: &[u8] = b"password";
        let password = SafeCell::new(PASSWORD.to_vec());
        let salt = generate_salt();
@@ -93,7 +92,7 @@ mod tests {

    #[test]
    // We should fuzz this
-    pub fn test_nonce_increment() {
+    fn test_nonce_increment() {
        let mut nonce = Nonce([0u8; NONCE_LENGTH]);
        nonce.increment();

--- a/server/crates/arbiter-server/src/crypto/integrity/v1.rs
+++ b/server/crates/arbiter-server/src/crypto/integrity/v1.rs
@@ -1,32 +1,29 @@
-use crate::actors::keyholder;
-use arbiter_crypto::hashing::Hashable;
-use hmac::Hmac;
-use sha2::Sha256;
-
-use diesel::{ExpressionMethods as _, QueryDsl, dsl::insert_into, sqlite::Sqlite};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::{actor::ActorRef, error::SendError};
-use sha2::Digest as _;
-
 use crate::{
-    actors::keyholder::{KeyHolder, SignIntegrity, VerifyIntegrity},
+    actors::vault::{self, GetState, SignIntegrity, Vault, VerifyIntegrity},
    db::{
        self,
        models::{IntegrityEnvelope, NewIntegrityEnvelope},
        schema::integrity_envelope,
    },
 };
+use arbiter_crypto::hashing::Hashable;
+
+use diesel::{ExpressionMethods as _, QueryDsl, dsl::insert_into, sqlite::Sqlite};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use hmac::Hmac;
+use kameo::{actor::ActorRef, error::SendError};
+use sha2::{Digest as _, Sha256};

 #[derive(Debug, thiserror::Error)]
 pub enum Error {
    #[error("Database error: {0}")]
    Database(#[from] db::DatabaseError),

-    #[error("KeyHolder error: {0}")]
-    Keyholder(#[from] keyholder::Error),
+    #[error("Vault error: {0}")]
+    Vault(#[from] vault::Error),

-    #[error("KeyHolder mailbox error")]
-    KeyholderSend,
+    #[error("Vault mailbox error")]
+    VaultSend,

    #[error("Integrity envelope is missing for entity {entity_kind}")]
    MissingEnvelope { entity_kind: &'static str },
@@ -103,7 +100,7 @@ impl IntoId for &'_ [u8] {

 pub async fn sign_entity<E: Integrable>(
    conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
    entity: &E,
    entity_id: impl IntoId,
 ) -> Result<(), Error> {
@@ -113,13 +110,14 @@ pub async fn sign_entity<E: Integrable>(

    let mac_input = build_mac_input(E::KIND, &entity_id, E::VERSION, &payload_hash);

-    let (key_version, mac) = keyholder
-        .ask(SignIntegrity { mac_input })
-        .await
-        .map_err(|err| match err {
-            kameo::error::SendError::HandlerError(inner) => Error::Keyholder(inner),
-            _ => Error::KeyholderSend,
-        })?;
+    let (key_version, mac) =
+        vault
+            .ask(SignIntegrity { mac_input })
+            .await
+            .map_err(|err| match err {
+                kameo::error::SendError::HandlerError(inner) => Error::Vault(inner),
+                _ => Error::VaultSend,
+            })?;

    insert_into(integrity_envelope::table)
        .values(NewIntegrityEnvelope {
@@ -148,7 +146,7 @@ pub async fn sign_entity<E: Integrable>(

 pub async fn verify_entity<E: Integrable>(
    conn: &mut impl AsyncConnection<Backend = Sqlite>,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
    entity: &E,
    entity_id: impl IntoId,
 ) -> Result<AttestationStatus, Error> {
@@ -176,7 +174,7 @@ pub async fn verify_entity<E: Integrable>(
    let payload_hash = payload_hash(&entity);
    let mac_input = build_mac_input(E::KIND, &entity_id, envelope.payload_version, &payload_hash);

-    let result = keyholder
+    let result = vault
        .ask(VerifyIntegrity {
            mac_input,
            expected_mac: envelope.mac,
@@ -189,13 +187,16 @@ pub async fn verify_entity<E: Integrable>(
        Ok(false) => Err(Error::MacMismatch {
            entity_kind: E::KIND,
        }),
-        Err(SendError::HandlerError(keyholder::Error::NotBootstrapped)) => {
-            Ok(AttestationStatus::Unavailable)
-        }
-        Err(_) => Err(Error::KeyholderSend),
+        Err(SendError::HandlerError(vault::Error::Sealed)) => Ok(AttestationStatus::Unavailable),
+        Err(_) => Err(Error::VaultSend),
    }
 }

+pub async fn is_signing_available(vault: &ActorRef<Vault>) -> Result<bool, Error> {
+    let state = vault.ask(GetState).await.map_err(|_| Error::VaultSend)?;
+    Ok(matches!(state, vault::VaultState::Unsealed))
+}
+
 #[cfg(test)]
 mod tests {
    use diesel::{ExpressionMethods as _, QueryDsl};
@@ -203,7 +204,10 @@ mod tests {
    use kameo::{actor::ActorRef, prelude::Spawn};

    use crate::{
-        actors::keyholder::{Bootstrap, KeyHolder},
+        actors::{
+            GlobalActors,
+            vault::{Bootstrap, Vault},
+        },
        db::{self, schema},
    };
    use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
@@ -218,8 +222,12 @@ mod tests {
        const KIND: &'static str = "dummy_entity";
    }

-    async fn bootstrapped_keyholder(db: &db::DatabasePool) -> ActorRef<KeyHolder> {
-        let actor = KeyHolder::spawn(KeyHolder::new(db.clone()).await.unwrap());
+    async fn bootstrapped_vault(db: &db::DatabasePool) -> ActorRef<Vault> {
+        let actor = Vault::spawn(
+            Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+                .await
+                .unwrap(),
+        );
        actor
            .ask(Bootstrap {
                seal_key_raw: SafeCell::new(b"integrity-test-seal-key".to_vec()),
@@ -232,7 +240,7 @@ mod tests {
    #[tokio::test]
    async fn sign_writes_envelope_and_verify_passes() {
        let db = db::create_test_pool().await;
-        let keyholder = bootstrapped_keyholder(&db).await;
+        let vault = bootstrapped_vault(&db).await;
        let mut conn = db.get().await.unwrap();

        const ENTITY_ID: &[u8] = b"entity-id-7";
@@ -242,7 +250,7 @@ mod tests {
            payload: b"payload-v1".to_vec(),
        };

-        sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
            .await
            .unwrap();

@@ -255,7 +263,7 @@ mod tests {
            .unwrap();

        assert_eq!(count, 1, "envelope row must be created exactly once");
-        verify_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        verify_entity(&mut conn, &vault, &entity, ENTITY_ID)
            .await
            .unwrap();
    }
@@ -263,7 +271,7 @@ mod tests {
    #[tokio::test]
    async fn tampered_mac_fails_verification() {
        let db = db::create_test_pool().await;
-        let keyholder = bootstrapped_keyholder(&db).await;
+        let vault = bootstrapped_vault(&db).await;
        let mut conn = db.get().await.unwrap();

        const ENTITY_ID: &[u8] = b"entity-id-11";
@@ -273,7 +281,7 @@ mod tests {
            payload: b"payload-v1".to_vec(),
        };

-        sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
            .await
            .unwrap();

@@ -285,7 +293,7 @@ mod tests {
            .await
            .unwrap();

-        let err = verify_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        let err = verify_entity(&mut conn, &vault, &entity, ENTITY_ID)
            .await
            .unwrap_err();
        assert!(matches!(err, Error::MacMismatch { .. }));
@@ -294,7 +302,7 @@ mod tests {
    #[tokio::test]
    async fn changed_payload_fails_verification() {
        let db = db::create_test_pool().await;
-        let keyholder = bootstrapped_keyholder(&db).await;
+        let vault = bootstrapped_vault(&db).await;
        let mut conn = db.get().await.unwrap();

        const ENTITY_ID: &[u8] = b"entity-id-21";
@@ -304,7 +312,7 @@ mod tests {
            payload: b"payload-v1".to_vec(),
        };

-        sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+        sign_entity(&mut conn, &vault, &entity, ENTITY_ID)
            .await
            .unwrap();

@@ -313,7 +321,7 @@ mod tests {
            ..entity
        };

-        let err = verify_entity(&mut conn, &keyholder, &tampered, ENTITY_ID)
+        let err = verify_entity(&mut conn, &vault, &tampered, ENTITY_ID)
            .await
            .unwrap_err();
        assert!(matches!(err, Error::MacMismatch { .. }));
--- a/server/crates/arbiter-server/src/crypto/mod.rs
+++ b/server/crates/arbiter-server/src/crypto/mod.rs
@@ -1,4 +1,5 @@
-use std::ops::Deref as _;
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use encryption::v1::{Nonce, Salt};

 use argon2::{Algorithm, Argon2};
 use chacha20poly1305::{
@@ -9,14 +10,11 @@ use rand::{
    Rng as _, SeedableRng as _,
    rngs::{StdRng, SysRng},
 };
-
-use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use std::ops::Deref as _;

 pub mod encryption;
 pub mod integrity;

-use encryption::v1::{Nonce, Salt};
-
 pub struct KeyCell(pub SafeCell<Key>);
 impl From<SafeCell<Key>> for KeyCell {
    fn from(value: SafeCell<Key>) -> Self {
@@ -144,7 +142,7 @@ mod tests {
    use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};

    #[test]
-    pub fn encrypt_decrypt() {
+    fn encrypt_decrypt() {
        static PASSWORD: &[u8] = b"password";
        let password = SafeCell::new(PASSWORD.to_vec());
        let salt = generate_salt();
--- a/server/crates/arbiter-server/src/db/mod.rs
+++ b/server/crates/arbiter-server/src/db/mod.rs
@@ -5,7 +5,6 @@ use diesel_async::{
    sync_connection_wrapper::SyncConnectionWrapper,
 };
 use diesel_migrations::{EmbeddedMigrations, MigrationHarness, embed_migrations};
-
 use thiserror::Error;
 use tracing::info;

--- a/server/crates/arbiter-server/src/db/models.rs
+++ b/server/crates/arbiter-server/src/db/models.rs
@@ -1,12 +1,12 @@
 #![allow(unused)]
 #![allow(clippy::all)]
-
 use crate::db::schema::{
    self, aead_encrypted, arbiter_settings, evm_basic_grant, evm_ether_transfer_grant,
    evm_ether_transfer_grant_target, evm_ether_transfer_limit, evm_token_transfer_grant,
    evm_token_transfer_log, evm_token_transfer_volume_limit, evm_transaction_log, evm_wallet,
    integrity_envelope, root_key_history, tls_history,
 };
+
 use chrono::{DateTime, Utc};
 use diesel::{prelude::*, sqlite::Sqlite};
 use restructed::Models;
@@ -195,7 +195,6 @@ pub struct ProgramClientMetadataHistory {
 #[diesel(table_name = schema::program_client, check_for_backend(Sqlite))]
 pub struct ProgramClient {
    pub id: i32,
-    pub nonce: i32,
    pub public_key: Vec<u8>,
    pub metadata_id: i32,
    pub created_at: SqliteTimestamp,
@@ -206,7 +205,6 @@ pub struct ProgramClient {
 #[diesel(table_name = schema::useragent_client, check_for_backend(Sqlite))]
 pub struct UseragentClient {
    pub id: i32,
-    pub nonce: i32,
    pub public_key: Vec<u8>,
    pub created_at: SqliteTimestamp,
    pub updated_at: SqliteTimestamp,
--- a/server/crates/arbiter-server/src/db/schema.rs
+++ b/server/crates/arbiter-server/src/db/schema.rs
@@ -155,7 +155,6 @@ diesel::table! {
 diesel::table! {
    program_client (id) {
        id -> Integer,
-        nonce -> Integer,
        public_key -> Binary,
        metadata_id -> Integer,
        created_at -> Integer,
@@ -189,9 +188,7 @@ diesel::table! {
 diesel::table! {
    useragent_client (id) {
        id -> Integer,
-        nonce -> Integer,
        public_key -> Binary,
-        key_type -> Integer,
        created_at -> Integer,
        updated_at -> Integer,
    }
--- a/server/crates/arbiter-server/src/evm/mod.rs
+++ b/server/crates/arbiter-server/src/evm/mod.rs
@@ -1,17 +1,5 @@
-pub mod abi;
-pub mod safe_signer;
-
-use alloy::{
-    consensus::TxEip1559,
-    primitives::{TxKind, U256},
-};
-use chrono::Utc;
-use diesel::{ExpressionMethods as _, QueryDsl as _, QueryResult, insert_into, sqlite::Sqlite};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-use kameo::actor::ActorRef;
-
 use crate::{
-    actors::keyholder::KeyHolder,
+    actors::vault::Vault,
    crypto::integrity,
    db::{
        self, DatabaseError,
@@ -27,6 +15,18 @@ use crate::{
    },
 };

+use alloy::{
+    consensus::TxEip1559,
+    primitives::{TxKind, U256},
+};
+use chrono::Utc;
+use diesel::{ExpressionMethods as _, QueryDsl as _, QueryResult, insert_into, sqlite::Sqlite};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use kameo::actor::ActorRef;
+
+pub mod abi;
+pub mod safe_signer;
+
 pub mod policies;
 mod utils;

@@ -138,7 +138,7 @@ async fn check_shared_constraints(
 // Supporting only EIP-1559 transactions for now, but we can easily extend this to support legacy transactions if needed
 pub struct Engine {
    db: db::DatabasePool,
-    keyholder: ActorRef<KeyHolder>,
+    vault: ActorRef<Vault>,
 }

 impl Engine {
@@ -158,7 +158,7 @@ impl Engine {
            .map_err(DatabaseError::from)?
            .ok_or(PolicyError::NoMatchingGrant)?;

-        integrity::verify_entity(&mut conn, &self.keyholder, &grant.settings, grant.id).await?;
+        integrity::verify_entity(&mut conn, &self.vault, &grant.settings, grant.id).await?;

        let mut violations = check_shared_constraints(
            &context,
@@ -207,8 +207,8 @@ impl Engine {
 }

 impl Engine {
-    pub fn new(db: db::DatabasePool, keyholder: ActorRef<KeyHolder>) -> Self {
-        Self { db, keyholder }
+    pub fn new(db: db::DatabasePool, vault: ActorRef<Vault>) -> Self {
+        Self { db, vault }
    }

    pub async fn create_grant<P: Policy>(
@@ -219,7 +219,7 @@ impl Engine {
        P::Settings: Clone,
    {
        let mut conn = self.db.get().await?;
-        let keyholder = self.keyholder.clone();
+        let vault = self.vault.clone();

        let id = conn
            .transaction(|conn| {
@@ -258,7 +258,7 @@ impl Engine {

                    P::create_grant(&basic_grant, &full_grant.specific, conn).await?;

-                    integrity::sign_entity(conn, &keyholder, &full_grant, basic_grant.id)
+                    integrity::sign_entity(conn, &vault, &full_grant, basic_grant.id)
                        .await
                        .map_err(|_| diesel::result::Error::RollbackTransaction)?;

@@ -283,7 +283,7 @@ impl Engine {

        // Verify integrity of all grants before returning any results
        for grant in &all_grants {
-            integrity::verify_entity(conn, &self.keyholder, &grant.settings, grant.id).await?;
+            integrity::verify_entity(conn, &self.vault, &grant.settings, grant.id).await?;
        }

        Ok(all_grants.into_iter().map(|g| Grant {
--- a/server/crates/arbiter-server/src/evm/policies.rs
+++ b/server/crates/arbiter-server/src/evm/policies.rs
@@ -1,4 +1,8 @@
-use std::fmt::Display;
+use crate::{
+    crypto::integrity::v1::Integrable,
+    db::models::{self, EvmBasicGrant, EvmWalletAccess},
+    evm::utils,
+};

 use alloy::primitives::{Address, Bytes, ChainId, U256};
 use chrono::{DateTime, Duration, Utc};
@@ -6,15 +10,9 @@ use diesel::{
    ExpressionMethods as _, QueryDsl, SelectableHelper, result::QueryResult, sqlite::Sqlite,
 };
 use diesel_async::{AsyncConnection, RunQueryDsl};
-
+use std::fmt::Display;
 use thiserror::Error;

-use crate::{
-    crypto::integrity::v1::Integrable,
-    db::models::{self, EvmBasicGrant, EvmWalletAccess},
-    evm::utils,
-};
-
 pub mod ether_transfer;
 pub mod token_transfers;

--- a/server/crates/arbiter-server/src/evm/policies/ether_transfer/mod.rs
+++ b/server/crates/arbiter-server/src/evm/policies/ether_transfer/mod.rs
@@ -1,30 +1,33 @@
-use std::collections::HashMap;
-use std::fmt::Display;
-
-use alloy::primitives::{Address, U256};
-use chrono::{DateTime, Duration, Utc};
-use diesel::dsl::{auto_type, insert_into};
-use diesel::sqlite::Sqlite;
-use diesel::{ExpressionMethods, JoinOnDsl, prelude::*};
-use diesel_async::{AsyncConnection, RunQueryDsl};
-
-use crate::crypto::integrity::v1::Integrable;
-use crate::db::models::{
-    EvmBasicGrant, EvmEtherTransferGrant, EvmEtherTransferGrantTarget, EvmEtherTransferLimit,
-    NewEvmEtherTransferLimit, SqliteTimestamp,
-};
-use crate::db::schema::{evm_basic_grant, evm_ether_transfer_limit, evm_transaction_log};
-use crate::evm::policies::{
-    CombinedSettings, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning, VolumeRateLimit,
-};
+use super::{DatabaseID, EvalContext, EvalViolation};
 use crate::{
+    crypto::integrity::v1::Integrable,
+    db::models::{
+        EvmBasicGrant, EvmEtherTransferGrant, EvmEtherTransferGrantTarget, EvmEtherTransferLimit,
+        NewEvmEtherTransferLimit, SqliteTimestamp,
+    },
+    db::schema::{evm_basic_grant, evm_ether_transfer_limit, evm_transaction_log},
    db::{
        models::{self, NewEvmEtherTransferGrant, NewEvmEtherTransferGrantTarget},
        schema::{evm_ether_transfer_grant, evm_ether_transfer_grant_target},
    },
+    evm::policies::{
+        CombinedSettings, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
+        VolumeRateLimit,
+    },
    evm::{policies::Policy, utils},
 };

+use alloy::primitives::{Address, U256};
+use chrono::{DateTime, Duration, Utc};
+use diesel::{
+    ExpressionMethods, JoinOnDsl,
+    dsl::{auto_type, insert_into},
+    prelude::*,
+    sqlite::Sqlite,
+};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use std::{collections::HashMap, fmt::Display};
+
 #[auto_type]
 fn grant_join() -> _ {
    evm_ether_transfer_grant::table.inner_join(
@@ -32,8 +35,6 @@ fn grant_join() -> _ {
    )
 }

-use super::{DatabaseID, EvalContext, EvalViolation};
-
 // Plain ether transfer
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Meaning {
--- a/server/crates/arbiter-server/src/evm/policies/ether_transfer/tests.rs
+++ b/server/crates/arbiter-server/src/evm/policies/ether_transfer/tests.rs
@@ -1,25 +1,26 @@
+use super::{EtherTransfer, Settings};
+use crate::{
+    db::{
+        self, DatabaseConnection,
+        models::{
+            EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, NewEvmTransactionLog, SqliteTimestamp,
+        },
+        schema::{evm_basic_grant, evm_transaction_log},
+    },
+    evm::{
+        policies::{
+            CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
+            VolumeRateLimit,
+        },
+        utils,
+    },
+};
+
 use alloy::primitives::{Address, Bytes, U256, address};
 use chrono::{Duration, Utc};
 use diesel::{SelectableHelper, insert_into};
 use diesel_async::RunQueryDsl;

-use crate::db::{
-    self, DatabaseConnection,
-    models::{
-        EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, NewEvmTransactionLog, SqliteTimestamp,
-    },
-    schema::{evm_basic_grant, evm_transaction_log},
-};
-use crate::evm::{
-    policies::{
-        CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
-        VolumeRateLimit,
-    },
-    utils,
-};
-
-use super::{EtherTransfer, Settings};
-
 const WALLET_ACCESS_ID: i32 = 1;
 const CHAIN_ID: u64 = 1;

--- a/server/crates/arbiter-server/src/evm/policies/token_transfers/mod.rs
+++ b/server/crates/arbiter-server/src/evm/policies/token_transfers/mod.rs
@@ -1,16 +1,4 @@
-use std::collections::HashMap;
-
-use crate::db::schema::{
-    evm_basic_grant, evm_token_transfer_grant, evm_token_transfer_log,
-    evm_token_transfer_volume_limit,
-};
-use crate::evm::{
-    abi::IERC20::transferCall,
-    policies::{
-        Grant, Policy, SharedGrantSettings, SpecificGrant, SpecificMeaning, VolumeRateLimit,
-    },
-    utils,
-};
+use super::{DatabaseID, EvalContext, EvalViolation};
 use crate::{
    crypto::integrity::Integrable,
    db::models::{
@@ -18,20 +6,34 @@ use crate::{
        NewEvmTokenTransferGrant, NewEvmTokenTransferLog, NewEvmTokenTransferVolumeLimit,
        SqliteTimestamp,
    },
+    db::schema::{
+        evm_basic_grant, evm_token_transfer_grant, evm_token_transfer_log,
+        evm_token_transfer_volume_limit,
+    },
    evm::policies::CombinedSettings,
+    evm::{
+        abi::IERC20::transferCall,
+        policies::{
+            Grant, Policy, SharedGrantSettings, SpecificGrant, SpecificMeaning, VolumeRateLimit,
+        },
+        utils,
+    },
 };
+use arbiter_tokens_registry::evm::nonfungible::{self, TokenInfo};
+
 use alloy::{
    primitives::{Address, U256},
    sol_types::SolCall,
 };
-use arbiter_tokens_registry::evm::nonfungible::{self, TokenInfo};
 use chrono::{DateTime, Duration, Utc};
-use diesel::dsl::{auto_type, insert_into};
-use diesel::sqlite::Sqlite;
-use diesel::{ExpressionMethods, prelude::*};
+use diesel::{
+    ExpressionMethods,
+    dsl::{auto_type, insert_into},
+    prelude::*,
+    sqlite::Sqlite,
+};
 use diesel_async::{AsyncConnection, RunQueryDsl};
-
-use super::{DatabaseID, EvalContext, EvalViolation};
+use std::collections::HashMap;

 #[auto_type]
 fn grant_join() -> _ {
--- a/server/crates/arbiter-server/src/evm/policies/token_transfers/tests.rs
+++ b/server/crates/arbiter-server/src/evm/policies/token_transfers/tests.rs
@@ -1,25 +1,28 @@
-use alloy::primitives::{Address, Bytes, U256, address};
-use alloy::sol_types::SolCall;
+use super::{Settings, TokenTransfer};
+use crate::{
+    db::{
+        self, DatabaseConnection,
+        models::{EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, SqliteTimestamp},
+        schema::evm_basic_grant,
+    },
+    evm::{
+        abi::IERC20::transferCall,
+        policies::{
+            CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
+            VolumeRateLimit,
+        },
+        utils,
+    },
+};
+
+use alloy::{
+    primitives::{Address, Bytes, U256, address},
+    sol_types::SolCall,
+};
 use chrono::{Duration, Utc};
 use diesel::{SelectableHelper, insert_into};
 use diesel_async::RunQueryDsl;

-use crate::db::{
-    self, DatabaseConnection,
-    models::{EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, SqliteTimestamp},
-    schema::evm_basic_grant,
-};
-use crate::evm::{
-    abi::IERC20::transferCall,
-    policies::{
-        CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
-        VolumeRateLimit,
-    },
-    utils,
-};
-
-use super::{Settings, TokenTransfer};
-
 // DAI on Ethereum mainnet — present in the static token registry
 const CHAIN_ID: u64 = 1;
 const DAI: Address = address!("6B175474E89094C44Da98b954EedeAC495271d0F");
--- a/server/crates/arbiter-server/src/evm/safe_signer.rs
+++ b/server/crates/arbiter-server/src/evm/safe_signer.rs
@@ -1,4 +1,4 @@
-use std::sync::Mutex;
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};

 use alloy::{
    consensus::SignableTransaction,
@@ -6,9 +6,9 @@ use alloy::{
    primitives::{Address, B256, ChainId, Signature},
    signers::{Error, Result, Signer, SignerSync, utils::secret_key_to_address},
 };
-use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use async_trait::async_trait;
 use k256::ecdsa::{self, RecoveryId, SigningKey, signature::hazmat::PrehashSigner};
+use std::sync::Mutex;

 /// An Ethereum signer that stores its secp256k1 secret key inside a
 /// hardware-protected [`MemSafe`] cell.
--- a/server/crates/arbiter-server/src/evm/utils.rs
+++ b/server/crates/arbiter-server/src/evm/utils.rs
@@ -2,20 +2,20 @@ use alloy::primitives::U256;

 #[derive(thiserror::Error, Debug)]
 #[error("Expected {expected} bytes but got {actual} bytes")]
-pub struct LengthError {
-    pub expected: usize,
-    pub actual: usize,
+pub(super) struct LengthError {
+    pub(super) expected: usize,
+    pub(super) actual: usize,
 }

-pub fn u256_to_bytes(value: U256) -> [u8; 32] {
+pub(super) fn u256_to_bytes(value: U256) -> [u8; 32] {
    value.to_le_bytes()
 }
-pub fn bytes_to_u256(bytes: &[u8]) -> Option<U256> {
+pub(super) fn bytes_to_u256(bytes: &[u8]) -> Option<U256> {
    let bytes: [u8; 32] = bytes.try_into().ok()?;
    Some(U256::from_le_bytes(bytes))
 }

-pub fn try_bytes_to_u256(bytes: &[u8]) -> diesel::result::QueryResult<U256> {
+pub(super) fn try_bytes_to_u256(bytes: &[u8]) -> diesel::result::QueryResult<U256> {
    let bytes: [u8; 32] = bytes.try_into().map_err(|_| {
        diesel::result::Error::DeserializationError(Box::new(LengthError {
            expected: 32,
--- a/server/crates/arbiter-server/src/grpc/client.rs
+++ b/server/crates/arbiter-server/src/grpc/client.rs
@@ -1,3 +1,7 @@
+use crate::{
+    grpc::request_tracker::RequestTracker,
+    peers::client::{ClientConnection, session::ClientSession},
+};
 use arbiter_proto::{
    proto::client::{
        ClientRequest, ClientResponse, client_request::Payload as ClientRequestPayload,
@@ -5,15 +9,11 @@ use arbiter_proto::{
    },
    transport::{Receiver, Sender, grpc::GrpcBi},
 };
+
 use kameo::actor::{ActorRef, Spawn as _};
 use tonic::Status;
 use tracing::{info, warn};

-use crate::{
-    actors::client::{ClientConnection, session::ClientSession},
-    grpc::request_tracker::RequestTracker,
-};
-
 mod auth;
 mod evm;
 mod inbound;
--- a/server/crates/arbiter-server/src/grpc/client/auth.rs
+++ b/server/crates/arbiter-server/src/grpc/client/auth.rs
@@ -1,3 +1,7 @@
+use crate::{
+    grpc::request_tracker::RequestTracker,
+    peers::client::{self, ClientConnection, auth},
+};
 use arbiter_crypto::authn;
 use arbiter_proto::{
    ClientMetadata,
@@ -17,22 +21,18 @@ use arbiter_proto::{
    },
    transport::{Bi, Error as TransportError, Receiver, Sender, grpc::GrpcBi},
 };
+
 use async_trait::async_trait;
 use tonic::Status;
 use tracing::warn;

-use crate::{
-    actors::client::{self, ClientConnection, auth},
-    grpc::request_tracker::RequestTracker,
-};
-
-pub struct AuthTransportAdapter<'a> {
+pub(super) struct AuthTransportAdapter<'a> {
    bi: &'a mut GrpcBi<ClientRequest, ClientResponse>,
    request_tracker: &'a mut RequestTracker,
 }

 impl<'a> AuthTransportAdapter<'a> {
-    pub fn new(
+    pub(super) fn new(
        bi: &'a mut GrpcBi<ClientRequest, ClientResponse>,
        request_tracker: &'a mut RequestTracker,
    ) -> Self {
@@ -44,10 +44,14 @@ impl<'a> AuthTransportAdapter<'a> {

    fn response_to_proto(response: auth::Outbound) -> AuthResponsePayload {
        match response {
-            auth::Outbound::AuthChallenge { pubkey, nonce } => {
+            auth::Outbound::AuthChallenge { challenge } => {
                AuthResponsePayload::Challenge(ProtoAuthChallenge {
-                    pubkey: pubkey.to_bytes(),
-                    nonce,
+                    timestamp_nanos: challenge
+                        .timestamp
+                        .timestamp_nanos_opt()
+                        .expect("timestamp within range")
+                        as u64,
+                    random: challenge.nonce.to_vec(),
                })
            }
            auth::Outbound::AuthSuccess => {
@@ -193,7 +197,7 @@ fn client_metadata_from_proto(metadata: ProtoClientInfo) -> ClientMetadata {
    }
 }

-pub async fn start(
+pub(super) async fn start(
    conn: &mut ClientConnection,
    bi: &mut GrpcBi<ClientRequest, ClientResponse>,
    request_tracker: &mut RequestTracker,
--- a/server/crates/arbiter-server/src/grpc/client/evm.rs
+++ b/server/crates/arbiter-server/src/grpc/client/evm.rs
@@ -1,3 +1,10 @@
+use crate::{
+    grpc::{
+        Convert, TryConvert,
+        common::inbound::{RawEvmAddress, RawEvmTransaction},
+    },
+    peers::client::session::{ClientSession, HandleSignTransaction, SignTransactionRpcError},
+};
 use arbiter_proto::proto::{
    client::{
        client_response::Payload as ClientResponsePayload,
@@ -11,18 +18,11 @@ use arbiter_proto::proto::{
        evm_sign_transaction_response::Result as EvmSignTransactionResult,
    },
 };
+
 use kameo::actor::ActorRef;
 use tonic::Status;
 use tracing::warn;

-use crate::{
-    actors::client::session::{ClientSession, HandleSignTransaction, SignTransactionRpcError},
-    grpc::{
-        Convert, TryConvert,
-        common::inbound::{RawEvmAddress, RawEvmTransaction},
-    },
-};
-
 fn wrap_response(payload: EvmResponsePayload) -> ClientResponsePayload {
    ClientResponsePayload::Evm(proto_evm::Response {
        payload: Some(payload),
--- a/server/crates/arbiter-server/src/grpc/client/vault.rs
+++ b/server/crates/arbiter-server/src/grpc/client/vault.rs
@@ -1,3 +1,7 @@
+use crate::{
+    actors::vault::VaultState,
+    peers::client::session::{ClientSession, Error, HandleQueryVaultState},
+};
 use arbiter_proto::proto::{
    client::{
        client_response::Payload as ClientResponsePayload,
@@ -8,15 +12,11 @@ use arbiter_proto::proto::{
    },
    shared::VaultState as ProtoVaultState,
 };
+
 use kameo::{actor::ActorRef, error::SendError};
 use tonic::Status;
 use tracing::warn;

-use crate::actors::{
-    client::session::{ClientSession, Error, HandleQueryVaultState},
-    keyholder::KeyHolderState,
-};
-
 pub(super) async fn dispatch(
    actor: &ActorRef<ClientSession>,
    req: proto_vault::Request,
@@ -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");
--- a/server/crates/arbiter-server/src/grpc/common.rs
+++ b/server/crates/arbiter-server/src/grpc/common.rs
@@ -1,2 +1,2 @@
-pub mod inbound;
-pub mod outbound;
+pub(super) mod inbound;
+pub(super) mod outbound;
--- a/server/crates/arbiter-server/src/grpc/common/inbound.rs
+++ b/server/crates/arbiter-server/src/grpc/common/inbound.rs
@@ -1,8 +1,8 @@
-use alloy::{consensus::TxEip1559, primitives::Address, rlp::Decodable as _};
-
 use crate::grpc::TryConvert;

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

@@ -21,7 +21,7 @@ impl TryConvert for RawEvmAddress {
    }
 }

-pub struct RawEvmTransaction(pub Vec<u8>);
+pub(in crate::grpc) struct RawEvmTransaction(pub(in crate::grpc) Vec<u8>);
 impl TryConvert for RawEvmTransaction {
    type Output = TxEip1559;

--- a/server/crates/arbiter-server/src/grpc/common/outbound.rs
+++ b/server/crates/arbiter-server/src/grpc/common/outbound.rs
@@ -1,4 +1,10 @@
-use alloy::primitives::U256;
+use crate::{
+    evm::{
+        PolicyError, VetError,
+        policies::{EvalViolation, SpecificMeaning},
+    },
+    grpc::Convert,
+};
 use arbiter_proto::proto::{
    evm::{
        EvmError as ProtoEvmError,
@@ -14,13 +20,7 @@ use arbiter_proto::proto::{
    },
 };

-use crate::{
-    evm::{
-        PolicyError, VetError,
-        policies::{EvalViolation, SpecificMeaning},
-    },
-    grpc::Convert,
-};
+use alloy::primitives::U256;

 fn u256_to_proto_bytes(value: U256) -> Vec<u8> {
    value.to_be_bytes::<32>().to_vec()
--- a/server/crates/arbiter-server/src/grpc/mod.rs
+++ b/server/crates/arbiter-server/src/grpc/mod.rs
@@ -1,3 +1,4 @@
+use crate::peers::{client::ClientConnection, user_agent::UserAgentConnection};
 use arbiter_proto::{
    proto::{
        client::{ClientRequest, ClientResponse},
@@ -5,15 +6,11 @@ use arbiter_proto::{
    },
    transport::grpc::GrpcBi,
 };
+
 use tokio_stream::wrappers::ReceiverStream;
 use tonic::{Request, Response, Status, async_trait};
 use tracing::info;

-use crate::{
-    actors::{client::ClientConnection, user_agent::UserAgentConnection},
-    grpc::user_agent::start,
-};
-
 mod request_tracker;

 pub mod client;
@@ -63,7 +60,7 @@ impl arbiter_proto::proto::arbiter_service_server::ArbiterService for super::Ser

        let (bi, rx) = GrpcBi::from_bi_stream(req_stream);

-        tokio::spawn(start(
+        tokio::spawn(user_agent::start(
            UserAgentConnection {
                db: self.context.db.clone(),
                actors: self.context.actors.clone(),
--- a/server/crates/arbiter-server/src/grpc/request_tracker.rs
+++ b/server/crates/arbiter-server/src/grpc/request_tracker.rs
@@ -1,12 +1,12 @@
 use tonic::Status;

 #[derive(Default)]
-pub struct RequestTracker {
+pub(super) struct RequestTracker {
    next_request_id: i32,
 }

 impl RequestTracker {
-    pub fn request(&mut self, id: i32) -> Result<i32, Status> {
+    pub(super) fn request(&mut self, id: i32) -> Result<i32, Status> {
        if id < self.next_request_id {
            return Err(Status::invalid_argument("Duplicate request id"));
        }
@@ -20,7 +20,7 @@ impl RequestTracker {

    // This is used to set the response id for auth responses, which need to match the request id of the auth challenge request.
    // -1 offset is needed because request() increments the next_request_id after returning the current request id.
-    pub fn current_request_id(&self) -> i32 {
+    pub(super) fn current_request_id(&self) -> i32 {
        self.next_request_id - 1
    }
 }
--- a/server/crates/arbiter-server/src/grpc/user_agent.rs
+++ b/server/crates/arbiter-server/src/grpc/user_agent.rs
@@ -1,5 +1,7 @@
-use tokio::sync::mpsc;
-
+use crate::{
+    grpc::request_tracker::RequestTracker,
+    peers::user_agent::{OutOfBand, UserAgentConnection, UserAgentSession},
+};
 use arbiter_proto::{
    proto::user_agent::{
        UserAgentRequest, UserAgentResponse,
@@ -8,22 +10,20 @@ use arbiter_proto::{
    },
    transport::{Error as TransportError, Receiver, Sender, grpc::GrpcBi},
 };
+
 use async_trait::async_trait;
-use kameo::actor::{ActorRef, Spawn as _};
+use kameo::actor::ActorRef;
+use tokio::sync::mpsc;
 use tonic::Status;
 use tracing::{error, info, warn};

-use crate::{
-    actors::user_agent::{OutOfBand, UserAgentConnection, UserAgentSession},
-    grpc::request_tracker::RequestTracker,
-};
-
 mod auth;
 mod evm;
 mod inbound;
 mod outbound;
 mod sdk_client;
 mod vault;
+mod vault_gate;

 pub struct OutOfBandAdapter(mpsc::Sender<OutOfBand>);

@@ -124,21 +124,22 @@ pub async fn start(
 ) {
    let mut request_tracker = RequestTracker::default();

-    let pubkey = match auth::start(&mut conn, &mut bi, &mut request_tracker).await {
-        Ok(pubkey) => pubkey,
-        Err(e) => {
-            warn!(error = ?e, "Authentication failed");
-            return;
-        }
-    };
-
    let (oob_sender, oob_receiver) = mpsc::channel(16);
    let oob_adapter = OutOfBandAdapter(oob_sender);

-    let actor = UserAgentSession::spawn(UserAgentSession::new(conn, Box::new(oob_adapter)));
-    let actor_for_cleanup = actor.clone();
+    let actor = {
+        let transport = auth::AuthTransportAdapter::new(&mut bi, &mut request_tracker);
+        match crate::peers::user_agent::start(&mut conn, transport, Box::new(oob_adapter)).await {
+            Ok(actor) => actor,
+            Err(e) => {
+                warn!(error = ?e, "User agent connection failed");
+                return;
+            }
+        }
+    };

-    info!(?pubkey, "User authenticated successfully");
-    dispatch_loop(bi, actor, oob_receiver, request_tracker).await;
-    actor_for_cleanup.kill();
+    info!("User agent session established");
+
+    dispatch_loop(bi, actor.clone(), oob_receiver, request_tracker).await;
+    actor.kill();
 }
--- a/server/crates/arbiter-server/src/grpc/user_agent/auth.rs
+++ b/server/crates/arbiter-server/src/grpc/user_agent/auth.rs
@@ -1,3 +1,4 @@
+use crate::{grpc::request_tracker::RequestTracker, peers::user_agent::auth};
 use arbiter_crypto::authn;
 use arbiter_proto::{
    proto::user_agent::{
@@ -13,22 +14,18 @@ use arbiter_proto::{
    },
    transport::{Bi, Error as TransportError, Receiver, Sender, grpc::GrpcBi},
 };
+
 use async_trait::async_trait;
 use tonic::Status;
 use tracing::warn;

-use crate::{
-    actors::user_agent::{UserAgentConnection, auth},
-    grpc::request_tracker::RequestTracker,
-};
-
-pub struct AuthTransportAdapter<'a> {
-    bi: &'a mut GrpcBi<UserAgentRequest, UserAgentResponse>,
-    request_tracker: &'a mut RequestTracker,
+pub(super) struct AuthTransportAdapter<'a> {
+    pub(super) bi: &'a mut GrpcBi<UserAgentRequest, UserAgentResponse>,
+    pub(super) request_tracker: &'a mut RequestTracker,
 }

 impl<'a> AuthTransportAdapter<'a> {
-    pub fn new(
+    pub(super) fn new(
        bi: &'a mut GrpcBi<UserAgentRequest, UserAgentResponse>,
        request_tracker: &'a mut RequestTracker,
    ) -> Self {
@@ -38,19 +35,35 @@ impl<'a> AuthTransportAdapter<'a> {
        }
    }

-    async fn send_user_agent_response(
+    pub(super) fn bi_mut(&mut self) -> &mut GrpcBi<UserAgentRequest, UserAgentResponse> {
+        self.bi
+    }
+
+    pub(super) fn tracker_mut(&mut self) -> &mut RequestTracker {
+        self.request_tracker
+    }
+
+    pub(super) async fn send_response_payload(
        &mut self,
-        payload: AuthResponsePayload,
+        payload: UserAgentResponsePayload,
    ) -> Result<(), TransportError> {
        self.bi
            .send(Ok(UserAgentResponse {
                id: Some(self.request_tracker.current_request_id()),
-                payload: Some(UserAgentResponsePayload::Auth(proto_auth::Response {
-                    payload: Some(payload),
-                })),
+                payload: Some(payload),
            }))
            .await
    }
+
+    async fn send_user_agent_response(
+        &mut self,
+        payload: AuthResponsePayload,
+    ) -> Result<(), TransportError> {
+        self.send_response_payload(UserAgentResponsePayload::Auth(proto_auth::Response {
+            payload: Some(payload),
+        }))
+        .await
+    }
 }

 #[async_trait]
@@ -61,8 +74,15 @@ impl Sender<Result<auth::Outbound, auth::Error>> for AuthTransportAdapter<'_> {
    ) -> Result<(), TransportError> {
        use auth::{Error, Outbound};
        let payload = match item {
-            Ok(Outbound::AuthChallenge { nonce }) => {
-                AuthResponsePayload::Challenge(ProtoAuthChallenge { nonce })
+            Ok(Outbound::AuthChallenge { challenge }) => {
+                AuthResponsePayload::Challenge(ProtoAuthChallenge {
+                    timestamp_nanos: challenge
+                        .timestamp
+                        .timestamp_nanos_opt()
+                        .expect("timestamp within range")
+                        as u64,
+                    random: challenge.nonce.to_vec(),
+                })
            }
            Ok(Outbound::AuthSuccess) => {
                AuthResponsePayload::Result(ProtoAuthResult::Success.into())
@@ -140,7 +160,6 @@ impl Receiver<auth::Inbound> for AuthTransportAdapter<'_> {
            AuthRequestPayload::ChallengeRequest(ProtoAuthChallengeRequest {
                pubkey,
                bootstrap_token,
-                key_type: _,
            }) => {
                let Ok(pubkey) = authn::PublicKey::try_from(pubkey.as_slice()) else {
                    warn!(
@@ -163,12 +182,3 @@ impl Receiver<auth::Inbound> for AuthTransportAdapter<'_> {
 }

 impl Bi<auth::Inbound, Result<auth::Outbound, auth::Error>> for AuthTransportAdapter<'_> {}
-
-pub async fn start(
-    conn: &mut UserAgentConnection,
-    bi: &mut GrpcBi<UserAgentRequest, UserAgentResponse>,
-    request_tracker: &mut RequestTracker,
-) -> Result<authn::PublicKey, auth::Error> {
-    let transport = AuthTransportAdapter::new(bi, request_tracker);
-    auth::authenticate(conn, transport).await
-}
--- a/server/crates/arbiter-server/src/grpc/user_agent/evm.rs
+++ b/server/crates/arbiter-server/src/grpc/user_agent/evm.rs
@@ -1,3 +1,17 @@
+use crate::{
+    grpc::{
+        Convert, TryConvert,
+        common::inbound::{RawEvmAddress, RawEvmTransaction},
+    },
+    peers::user_agent::{
+        UserAgentSession,
+        session::handlers::{
+            GrantMutationError, HandleEvmWalletCreate, HandleEvmWalletList, HandleGrantCreate,
+            HandleGrantDelete, HandleGrantList, HandleSignTransaction,
+            SignTransactionError as SessionSignTransactionError,
+        },
+    },
+};
 use arbiter_proto::proto::{
    evm::{
        EvmError as ProtoEvmError, EvmGrantCreateRequest, EvmGrantCreateResponse,
@@ -18,25 +32,11 @@ use arbiter_proto::proto::{
        user_agent_response::Payload as UserAgentResponsePayload,
    },
 };
+
 use kameo::actor::ActorRef;
 use tonic::Status;
 use tracing::warn;

-use crate::{
-    actors::user_agent::{
-        UserAgentSession,
-        session::connection::{
-            GrantMutationError, HandleEvmWalletCreate, HandleEvmWalletList, HandleGrantCreate,
-            HandleGrantDelete, HandleGrantList, HandleSignTransaction,
-            SignTransactionError as SessionSignTransactionError,
-        },
-    },
-    grpc::{
-        Convert, TryConvert,
-        common::inbound::{RawEvmAddress, RawEvmTransaction},
-    },
-};
-
 fn wrap_evm_response(payload: EvmResponsePayload) -> UserAgentResponsePayload {
    UserAgentResponsePayload::Evm(proto_evm::Response {
        payload: Some(payload),
--- a/server/crates/arbiter-server/src/grpc/user_agent/inbound.rs
+++ b/server/crates/arbiter-server/src/grpc/user_agent/inbound.rs
@@ -1,26 +1,26 @@
-use alloy::primitives::{Address, U256};
-use arbiter_proto::proto::evm::{
-    EtherTransferSettings as ProtoEtherTransferSettings, SharedSettings as ProtoSharedSettings,
-    SpecificGrant as ProtoSpecificGrant, TokenTransferSettings as ProtoTokenTransferSettings,
-    TransactionRateLimit as ProtoTransactionRateLimit, VolumeRateLimit as ProtoVolumeRateLimit,
-    specific_grant::Grant as ProtoSpecificGrantType,
-};
-use arbiter_proto::proto::user_agent::sdk_client::{
-    WalletAccess, WalletAccessEntry as SdkClientWalletAccess,
-};
-use chrono::{DateTime, TimeZone, Utc};
-use prost_types::Timestamp as ProtoTimestamp;
-use tonic::Status;
-
-use crate::db::models::{CoreEvmWalletAccess, NewEvmWalletAccess};
-use crate::grpc::Convert;
 use crate::{
+    db::models::{CoreEvmWalletAccess, NewEvmWalletAccess},
    evm::policies::{
        SharedGrantSettings, SpecificGrant, TransactionRateLimit, VolumeRateLimit, ether_transfer,
        token_transfers,
    },
+    grpc::Convert,
    grpc::TryConvert,
 };
+use arbiter_proto::{
+    proto::evm::{
+        EtherTransferSettings as ProtoEtherTransferSettings, SharedSettings as ProtoSharedSettings,
+        SpecificGrant as ProtoSpecificGrant, TokenTransferSettings as ProtoTokenTransferSettings,
+        TransactionRateLimit as ProtoTransactionRateLimit, VolumeRateLimit as ProtoVolumeRateLimit,
+        specific_grant::Grant as ProtoSpecificGrantType,
+    },
+    proto::user_agent::sdk_client::{WalletAccess, WalletAccessEntry as SdkClientWalletAccess},
+};
+
+use alloy::primitives::{Address, U256};
+use chrono::{DateTime, TimeZone, Utc};
+use prost_types::Timestamp as ProtoTimestamp;
+use tonic::Status;

 fn address_from_bytes(bytes: Vec<u8>) -> Result<Address, Status> {
    if bytes.len() != 20 {
--- a/server/crates/arbiter-server/src/grpc/user_agent/outbound.rs
+++ b/server/crates/arbiter-server/src/grpc/user_agent/outbound.rs
@@ -1,3 +1,8 @@
+use crate::{
+    db::models::EvmWalletAccess,
+    evm::policies::{SharedGrantSettings, SpecificGrant, TransactionRateLimit, VolumeRateLimit},
+    grpc::Convert,
+};
 use arbiter_proto::proto::{
    evm::{
        EtherTransferSettings as ProtoEtherTransferSettings, SharedSettings as ProtoSharedSettings,
@@ -7,15 +12,10 @@ use arbiter_proto::proto::{
    },
    user_agent::sdk_client::{WalletAccess, WalletAccessEntry as ProtoSdkClientWalletAccess},
 };
+
 use chrono::{DateTime, Utc};
 use prost_types::Timestamp as ProtoTimestamp;

-use crate::{
-    db::models::EvmWalletAccess,
-    evm::policies::{SharedGrantSettings, SpecificGrant, TransactionRateLimit, VolumeRateLimit},
-    grpc::Convert,
-};
-
 impl Convert for DateTime<Utc> {
    type Output = ProtoTimestamp;

--- a/server/crates/arbiter-server/src/grpc/user_agent/sdk_client.rs
+++ b/server/crates/arbiter-server/src/grpc/user_agent/sdk_client.rs
@@ -1,3 +1,14 @@
+use crate::{
+    db::models::NewEvmWalletAccess,
+    grpc::Convert,
+    peers::user_agent::{
+        OutOfBand, UserAgentSession,
+        session::handlers::{
+            HandleGrantEvmWalletAccess, HandleListWalletAccess, HandleNewClientApprove,
+            HandleRevokeEvmWalletAccess, HandleSdkClientList,
+        },
+    },
+};
 use arbiter_crypto::authn;
 use arbiter_proto::proto::{
    shared::ClientInfo as ProtoClientMetadata,
@@ -16,22 +27,11 @@ use arbiter_proto::proto::{
        user_agent_response::Payload as UserAgentResponsePayload,
    },
 };
+
 use kameo::actor::ActorRef;
 use tonic::Status;
 use tracing::{info, warn};

-use crate::{
-    actors::user_agent::{
-        OutOfBand, UserAgentSession,
-        session::connection::{
-            HandleGrantEvmWalletAccess, HandleListWalletAccess, HandleNewClientApprove,
-            HandleRevokeEvmWalletAccess, HandleSdkClientList,
-        },
-    },
-    db::models::NewEvmWalletAccess,
-    grpc::Convert,
-};
-
 fn wrap_sdk_client_response(payload: SdkClientResponsePayload) -> UserAgentResponsePayload {
    UserAgentResponsePayload::SdkClient(proto_sdk_client::Response {
        payload: Some(payload),
--- a/server/crates/arbiter-server/src/grpc/user_agent/vault.rs
+++ b/server/crates/arbiter-server/src/grpc/user_agent/vault.rs
@@ -1,54 +1,28 @@
-use arbiter_proto::proto::shared::VaultState as ProtoVaultState;
-use arbiter_proto::proto::user_agent::{
-    user_agent_response::Payload as UserAgentResponsePayload,
-    vault::{
-        self as proto_vault,
-        bootstrap::{
-            self as proto_bootstrap, BootstrapEncryptedKey as ProtoBootstrapEncryptedKey,
-            BootstrapResult as ProtoBootstrapResult,
-        },
-        request::Payload as VaultRequestPayload,
-        response::Payload as VaultResponsePayload,
-        unseal::{
-            self as proto_unseal, UnsealEncryptedKey as ProtoUnsealEncryptedKey,
-            UnsealResult as ProtoUnsealResult, UnsealStart,
-            request::Payload as UnsealRequestPayload, response::Payload as UnsealResponsePayload,
+use crate::{
+    actors::vault::VaultState,
+    peers::user_agent::{UserAgentSession, session::handlers::HandleQueryVaultState},
+};
+use arbiter_proto::{
+    proto::shared::VaultState as ProtoVaultState,
+    proto::user_agent::{
+        user_agent_response::Payload as UserAgentResponsePayload,
+        vault::{
+            self as proto_vault, request::Payload as VaultRequestPayload,
+            response::Payload as VaultResponsePayload,
        },
    },
 };
-use kameo::{actor::ActorRef, error::SendError};
+
+use kameo::actor::ActorRef;
 use tonic::Status;
 use tracing::warn;

-use crate::actors::{
-    keyholder::KeyHolderState,
-    user_agent::{
-        UserAgentSession,
-        session::connection::{
-            BootstrapError, HandleBootstrapEncryptedKey, HandleQueryVaultState,
-            HandleUnsealEncryptedKey, HandleUnsealRequest, UnsealError,
-        },
-    },
-};
-
 fn wrap_vault_response(payload: VaultResponsePayload) -> UserAgentResponsePayload {
    UserAgentResponsePayload::Vault(proto_vault::Response {
        payload: Some(payload),
    })
 }

-fn wrap_unseal_response(payload: UnsealResponsePayload) -> UserAgentResponsePayload {
-    wrap_vault_response(VaultResponsePayload::Unseal(proto_unseal::Response {
-        payload: Some(payload),
-    }))
-}
-
-fn wrap_bootstrap_response(result: ProtoBootstrapResult) -> UserAgentResponsePayload {
-    wrap_vault_response(VaultResponsePayload::Bootstrap(proto_bootstrap::Response {
-        result: result.into(),
-    }))
-}
-
 pub(super) async fn dispatch(
    actor: &ActorRef<UserAgentSession>,
    req: proto_vault::Request,
@@ -59,116 +33,21 @@ 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
--- a/server/crates/arbiter-server/src/grpc/user_agent/vault_gate.rs
+++ b/server/crates/arbiter-server/src/grpc/user_agent/vault_gate.rs
@@ -0,0 +1,81 @@
+use super::auth::AuthTransportAdapter;
+use crate::{
+    grpc::TryConvert,
+    peers::user_agent::vault_gate::{self as vault_gate},
+};
+use arbiter_proto::transport::{Bi, Error as TransportError, Receiver, Sender};
+
+use async_trait::async_trait;
+use tonic::Status;
+use tracing::warn;
+
+mod inbound;
+mod outbound;
+
+#[async_trait]
+impl Receiver<vault_gate::Inbound> for AuthTransportAdapter<'_> {
+    async fn recv(&mut self) -> Option<vault_gate::Inbound> {
+        loop {
+            let request = match self.bi_mut().recv().await? {
+                Ok(request) => request,
+                Err(error) => {
+                    warn!(
+                        ?error,
+                        "Failed to receive user agent request during vault gate"
+                    );
+                    return None;
+                }
+            };
+
+            if let Err(err) = self.tracker_mut().request(request.id) {
+                let _ = self.bi_mut().send(Err(err)).await;
+                return None;
+            }
+
+            let Some(payload) = request.payload else {
+                let _ = self
+                    .bi_mut()
+                    .send(Err(Status::invalid_argument("Missing request payload")))
+                    .await;
+                return None;
+            };
+
+            match payload.try_convert() {
+                Ok(inbound) => return Some(inbound),
+                Err(status) => {
+                    let _ = self.bi_mut().send(Err(status)).await;
+                    return None;
+                }
+            }
+        }
+    }
+}
+
+#[async_trait]
+impl Sender<Result<vault_gate::Outbound, vault_gate::Error>> for AuthTransportAdapter<'_> {
+    async fn send(
+        &mut self,
+        item: Result<vault_gate::Outbound, vault_gate::Error>,
+    ) -> Result<(), TransportError> {
+        let outbound = match item {
+            Ok(outbound) => outbound,
+            Err(err) => {
+                warn!(?err, "vault gate produced transport-level error");
+                return self
+                    .bi_mut()
+                    .send(Err(Status::internal(err.to_string())))
+                    .await;
+            }
+        };
+
+        match outbound.try_convert() {
+            Ok(payload) => self.send_response_payload(payload).await,
+            Err(status) => self.bi_mut().send(Err(status)).await,
+        }
+    }
+}
+
+impl Bi<vault_gate::Inbound, Result<vault_gate::Outbound, vault_gate::Error>>
+    for AuthTransportAdapter<'_>
+{
+}
--- a/server/crates/arbiter-server/src/grpc/user_agent/vault_gate/inbound.rs
+++ b/server/crates/arbiter-server/src/grpc/user_agent/vault_gate/inbound.rs
@@ -0,0 +1,129 @@
+use crate::{
+    grpc::{Convert, TryConvert},
+    peers::user_agent::vault_gate::{
+        self as vault_gate, HandleBootstrapEncryptedKey, HandleHandshake, HandleUnsealEncryptedKey,
+    },
+};
+use arbiter_proto::proto::user_agent::{
+    user_agent_request::Payload as UserAgentRequestPayload,
+    vault::{
+        self as proto_vault,
+        bootstrap::{self as proto_bootstrap},
+        request::Payload as VaultRequestPayload,
+        unseal::{self as proto_unseal, request::Payload as UnsealRequestPayload},
+    },
+};
+
+use tonic::Status;
+
+impl TryConvert for UserAgentRequestPayload {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        match self {
+            UserAgentRequestPayload::Vault(req) => req.try_convert(),
+            _ => Err(Status::permission_denied(
+                "Only vault operations are permitted before unsealing",
+            )),
+        }
+    }
+}
+
+impl TryConvert for proto_vault::Request {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        self.payload
+            .ok_or_else(|| Status::invalid_argument("Missing vault request payload"))?
+            .try_convert()
+    }
+}
+
+impl TryConvert for VaultRequestPayload {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        match self {
+            VaultRequestPayload::QueryState(_) => Ok(vault_gate::Inbound::HandleVaultState),
+            VaultRequestPayload::Unseal(req) => req.try_convert(),
+            VaultRequestPayload::Bootstrap(req) => req.try_convert(),
+        }
+    }
+}
+
+impl TryConvert for proto_unseal::Request {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        self.payload
+            .ok_or_else(|| Status::invalid_argument("Missing unseal request payload"))?
+            .try_convert()
+    }
+}
+
+impl TryConvert for UnsealRequestPayload {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        match self {
+            UnsealRequestPayload::Start(start) => start.try_convert(),
+            UnsealRequestPayload::EncryptedKey(key) => Ok(key.convert()),
+        }
+    }
+}
+
+impl TryConvert for proto_unseal::UnsealStart {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        let bytes = <[u8; 32]>::try_from(self.client_pubkey)
+            .map_err(|_| Status::invalid_argument("Invalid X25519 public key"))?;
+        Ok(vault_gate::Inbound::HandleHandshake(HandleHandshake {
+            client_pubkey: x25519_dalek::PublicKey::from(bytes),
+        }))
+    }
+}
+
+impl Convert for proto_unseal::UnsealEncryptedKey {
+    type Output = vault_gate::Inbound;
+
+    fn convert(self) -> vault_gate::Inbound {
+        vault_gate::Inbound::HandleUnsealEncryptedKey(HandleUnsealEncryptedKey {
+            nonce: self.nonce,
+            ciphertext: self.ciphertext,
+            associated_data: self.associated_data,
+        })
+    }
+}
+
+impl TryConvert for proto_bootstrap::Request {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        self.encrypted_key
+            .ok_or_else(|| Status::invalid_argument("Missing bootstrap encrypted key"))?
+            .try_convert()
+    }
+}
+
+impl TryConvert for proto_bootstrap::BootstrapEncryptedKey {
+    type Output = vault_gate::Inbound;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<vault_gate::Inbound, Status> {
+        Ok(vault_gate::Inbound::HandleBootstrapEncryptedKey(
+            HandleBootstrapEncryptedKey {
+                nonce: self.nonce,
+                ciphertext: self.ciphertext,
+                associated_data: self.associated_data,
+            },
+        ))
+    }
+}
--- a/server/crates/arbiter-server/src/grpc/user_agent/vault_gate/outbound.rs
+++ b/server/crates/arbiter-server/src/grpc/user_agent/vault_gate/outbound.rs
@@ -0,0 +1,115 @@
+use crate::{
+    actors::vault::VaultState,
+    grpc::{Convert, TryConvert},
+    peers::user_agent::vault_gate::{self as vault_gate},
+};
+use arbiter_proto::proto::{
+    shared::VaultState as ProtoVaultState,
+    user_agent::{
+        user_agent_response::Payload as UserAgentResponsePayload,
+        vault::{
+            self as proto_vault,
+            bootstrap::{self as proto_bootstrap, BootstrapResult as ProtoBootstrapResult},
+            response::Payload as VaultResponsePayload,
+            unseal::{
+                self as proto_unseal, UnsealResult as ProtoUnsealResult,
+                response::Payload as UnsealResponsePayload,
+            },
+        },
+    },
+};
+
+use tonic::Status;
+use tracing::warn;
+
+fn wrap_vault_response(payload: VaultResponsePayload) -> UserAgentResponsePayload {
+    UserAgentResponsePayload::Vault(proto_vault::Response {
+        payload: Some(payload),
+    })
+}
+
+fn wrap_unseal_response(payload: UnsealResponsePayload) -> UserAgentResponsePayload {
+    wrap_vault_response(VaultResponsePayload::Unseal(proto_unseal::Response {
+        payload: Some(payload),
+    }))
+}
+
+fn wrap_bootstrap_response(result: ProtoBootstrapResult) -> UserAgentResponsePayload {
+    wrap_vault_response(VaultResponsePayload::Bootstrap(proto_bootstrap::Response {
+        result: result.into(),
+    }))
+}
+
+impl Convert for VaultState {
+    type Output = UserAgentResponsePayload;
+
+    fn convert(self) -> UserAgentResponsePayload {
+        let proto_state = match self {
+            VaultState::Unbootstrapped => ProtoVaultState::Unbootstrapped,
+            VaultState::Sealed => ProtoVaultState::Sealed,
+            VaultState::Unsealed => ProtoVaultState::Unsealed,
+        };
+        wrap_vault_response(VaultResponsePayload::State(proto_state.into()))
+    }
+}
+
+impl Convert for vault_gate::HandshakeResponse {
+    type Output = UserAgentResponsePayload;
+
+    fn convert(self) -> UserAgentResponsePayload {
+        wrap_unseal_response(UnsealResponsePayload::Start(
+            proto_unseal::UnsealStartResponse {
+                server_pubkey: self.server_pubkey.as_bytes().to_vec(),
+            },
+        ))
+    }
+}
+
+impl TryConvert for vault_gate::Outbound {
+    type Output = UserAgentResponsePayload;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<UserAgentResponsePayload, Status> {
+        match self {
+            vault_gate::Outbound::HandleVaultState(result) => result
+                .map_err(|err| {
+                    warn!(?err, "vault state query failed");
+                    Status::internal("Failed to query vault state")
+                })
+                .map(VaultState::convert),
+            vault_gate::Outbound::HandleHandshake(result) => result
+                .map_err(|err| {
+                    warn!(?err, "handshake failed");
+                    Status::internal("Failed to start unseal flow")
+                })
+                .map(vault_gate::HandshakeResponse::convert),
+            vault_gate::Outbound::HandleUnsealEncryptedKey(result) => {
+                let proto_result = match result {
+                    Ok(()) => ProtoUnsealResult::Success,
+                    Err(vault_gate::Error::InvalidKey) => ProtoUnsealResult::InvalidKey,
+                    Err(err) => {
+                        warn!(?err, "unseal failed");
+                        return Err(Status::internal("Failed to unseal vault"));
+                    }
+                };
+                Ok(wrap_unseal_response(UnsealResponsePayload::Result(
+                    proto_result.into(),
+                )))
+            }
+            vault_gate::Outbound::HandleBootstrapEncryptedKey(result) => {
+                let proto_result = match result {
+                    Ok(()) => ProtoBootstrapResult::Success,
+                    Err(vault_gate::Error::InvalidKey) => ProtoBootstrapResult::InvalidKey,
+                    Err(vault_gate::Error::AlreadyBootstrapped) => {
+                        ProtoBootstrapResult::AlreadyBootstrapped
+                    }
+                    Err(err) => {
+                        warn!(?err, "bootstrap failed");
+                        return Err(Status::internal("Failed to bootstrap vault"));
+                    }
+                };
+                Ok(wrap_bootstrap_response(proto_result))
+            }
+        }
+    }
+}
--- a/server/crates/arbiter-server/src/lib.rs
+++ b/server/crates/arbiter-server/src/lib.rs
@@ -7,6 +7,7 @@ pub mod crypto;
 pub mod db;
 pub mod evm;
 pub mod grpc;
+pub mod peers;
 pub mod utils;

 pub struct Server {
--- a/server/crates/arbiter-server/src/main.rs
+++ b/server/crates/arbiter-server/src/main.rs
@@ -1,9 +1,9 @@
-use std::net::SocketAddr;
-
-use anyhow::anyhow;
 use arbiter_proto::{proto::arbiter_service_server::ArbiterServiceServer, url::ArbiterUrl};
 use arbiter_server::{Server, actors::bootstrap::GetToken, context::ServerContext, db};
+
+use anyhow::anyhow;
 use rustls::crypto::aws_lc_rs;
+use std::net::SocketAddr;
 use tonic::transport::{Identity, ServerTlsConfig};
 use tracing::info;

--- a/server/crates/arbiter-server/src/actors/client/auth.rs
+++ b/server/crates/arbiter-server/src/actors/client/auth.rs
@@ -1,22 +1,9 @@
-use arbiter_crypto::authn::{self, CLIENT_CONTEXT};
-use arbiter_proto::{
-    ClientMetadata,
-    transport::{Bi, expect_message},
-};
-use chrono::Utc;
-use diesel::{
-    ExpressionMethods as _, OptionalExtension as _, QueryDsl as _, SelectableHelper as _,
-    dsl::insert_into, update,
-};
-use diesel_async::RunQueryDsl as _;
-use kameo::{actor::ActorRef, error::SendError};
-use tracing::error;
-
+use super::{ClientConnection, ClientCredentials, ClientProfile};
 use crate::{
    actors::{
-        client::{ClientConnection, ClientCredentials, ClientProfile},
+        GlobalActors,
        flow_coordinator::{self, RequestClientApproval},
-        keyholder::KeyHolder,
+        vault::Vault,
    },
    crypto::integrity::{self, AttestationStatus},
    db::{
@@ -25,6 +12,20 @@ use crate::{
        schema::program_client,
    },
 };
+use arbiter_crypto::authn::{self, AuthChallenge, CLIENT_CONTEXT};
+use arbiter_proto::{
+    ClientMetadata,
+    transport::{Bi, expect_message},
+};
+
+use chrono::Utc;
+use diesel::{
+    ExpressionMethods as _, OptionalExtension as _, QueryDsl as _, SelectableHelper as _,
+    dsl::insert_into, update,
+};
+use diesel_async::RunQueryDsl as _;
+use kameo::{actor::ActorRef, error::SendError};
+use tracing::error;

 #[derive(thiserror::Error, Debug, Clone, PartialEq, Eq)]
 pub enum Error {
@@ -72,19 +73,14 @@ pub enum Inbound {

 #[derive(Debug, Clone)]
 pub enum Outbound {
-    AuthChallenge {
-        pubkey: authn::PublicKey,
-        nonce: i32,
-    },
+    AuthChallenge { challenge: AuthChallenge },
    AuthSuccess,
 }

-/// Returns the current nonce and client ID for a registered client.
-/// Returns `None` if the pubkey is not registered.
-async fn get_current_nonce_and_id(
+async fn get_client_id(
    db: &db::DatabasePool,
    pubkey: &authn::PublicKey,
-) -> Result<Option<(i32, i32)>, Error> {
+) -> Result<Option<i32>, Error> {
    let pubkey_bytes = pubkey.to_bytes();
    let mut conn = db.get().await.map_err(|e| {
        error!(error = ?e, "Database pool error");
@@ -92,8 +88,8 @@ async fn get_current_nonce_and_id(
    })?;
    program_client::table
        .filter(program_client::public_key.eq(&pubkey_bytes))
-        .select((program_client::id, program_client::nonce))
-        .first::<(i32, i32)>(&mut conn)
+        .select(program_client::id)
+        .first::<i32>(&mut conn)
        .await
        .optional()
        .map_err(|e| {
@@ -104,7 +100,7 @@ async fn get_current_nonce_and_id(

 async fn verify_integrity(
    db: &db::DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
    pubkey: &authn::PublicKey,
 ) -> Result<(), Error> {
    let mut db_conn = db.get().await.map_err(|e| {
@@ -112,17 +108,16 @@ async fn verify_integrity(
        Error::DatabasePoolUnavailable
    })?;

-    let (id, nonce) = get_current_nonce_and_id(db, pubkey).await?.ok_or_else(|| {
+    let id = get_client_id(db, pubkey).await?.ok_or_else(|| {
        error!("Client not found during integrity verification");
        Error::DatabaseOperationFailed
    })?;

    let attestation = integrity::verify_entity(
        &mut db_conn,
-        keyholder,
+        vault,
        &ClientCredentials {
            pubkey: pubkey.clone(),
-            nonce,
        },
        id,
    )
@@ -140,57 +135,7 @@ async fn verify_integrity(
    Ok(())
 }

-/// Atomically increments the nonce and re-signs the integrity envelope.
-/// Returns the new nonce, which is used as the challenge nonce.
-async fn create_nonce(
-    db: &db::DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
-    pubkey: &authn::PublicKey,
-) -> Result<i32, Error> {
-    let pubkey_bytes = pubkey.to_bytes();
-    let pubkey = pubkey.clone();
-
-    let mut conn = db.get().await.map_err(|e| {
-        error!(error = ?e, "Database pool error");
-        Error::DatabasePoolUnavailable
-    })?;
-
-    conn.exclusive_transaction(|conn| {
-        let keyholder = keyholder.clone();
-        let pubkey = pubkey.clone();
-        Box::pin(async move {
-            let (id, new_nonce): (i32, i32) = update(program_client::table)
-                .filter(program_client::public_key.eq(&pubkey_bytes))
-                .set(program_client::nonce.eq(program_client::nonce + 1))
-                .returning((program_client::id, program_client::nonce))
-                .get_result(conn)
-                .await?;
-
-            integrity::sign_entity(
-                conn,
-                &keyholder,
-                &ClientCredentials {
-                    pubkey: pubkey.clone(),
-                    nonce: new_nonce,
-                },
-                id,
-            )
-            .await
-            .map_err(|e| {
-                error!(?e, "Integrity sign failed after nonce update");
-                Error::DatabaseOperationFailed
-            })?;
-
-            Ok(new_nonce)
-        })
-    })
-    .await
-}
-
-async fn approve_new_client(
-    actors: &crate::actors::GlobalActors,
-    profile: ClientProfile,
-) -> Result<(), Error> {
+async fn approve_new_client(actors: &GlobalActors, profile: ClientProfile) -> Result<(), Error> {
    let result = actors
        .flow_coordinator
        .ask(RequestClientApproval { client: profile })
@@ -212,7 +157,7 @@ async fn approve_new_client(

 async fn insert_client(
    db: &db::DatabasePool,
-    keyholder: &ActorRef<KeyHolder>,
+    vault: &ActorRef<Vault>,
    pubkey: &authn::PublicKey,
    metadata: &ClientMetadata,
 ) -> Result<i32, Error> {
@@ -226,11 +171,9 @@ async fn insert_client(
    })?;

    conn.exclusive_transaction(|conn| {
-        let keyholder = keyholder.clone();
+        let vault = vault.clone();
        let pubkey = pubkey.clone();
        Box::pin(async move {
-            const NONCE_START: i32 = 1;
-
            let metadata_id = insert_into(client_metadata::table)
                .values((
                    client_metadata::name.eq(&metadata.name),
@@ -245,7 +188,6 @@ async fn insert_client(
                .values((
                    program_client::public_key.eq(pubkey.to_bytes()),
                    program_client::metadata_id.eq(metadata_id),
-                    program_client::nonce.eq(NONCE_START),
                ))
                .on_conflict_do_nothing()
                .returning(program_client::id)
@@ -254,10 +196,9 @@ async fn insert_client(

            integrity::sign_entity(
                conn,
-                &keyholder,
+                &vault,
                &ClientCredentials {
                    pubkey: pubkey.clone(),
-                    nonce: NONCE_START,
                },
                client_id,
            )
@@ -347,15 +288,14 @@ async fn sync_client_metadata(
 async fn challenge_client<T>(
    transport: &mut T,
    pubkey: authn::PublicKey,
-    nonce: i32,
+    challenge: AuthChallenge,
 ) -> Result<(), Error>
 where
    T: Bi<Inbound, Result<Outbound, Error>> + ?Sized,
 {
    transport
        .send(Ok(Outbound::AuthChallenge {
-            pubkey: pubkey.clone(),
-            nonce,
+            challenge: challenge.clone(),
        }))
        .await
        .map_err(|e| {
@@ -373,7 +313,7 @@ where
        Error::Transport
    })?;

-    if !pubkey.verify(nonce, CLIENT_CONTEXT, &signature) {
+    if !pubkey.verify(&challenge, CLIENT_CONTEXT, &signature) {
        error!("Challenge solution verification failed");
        return Err(Error::InvalidChallengeSolution);
    }
@@ -389,9 +329,9 @@ where
        return Err(Error::Transport);
    };

-    let client_id = match get_current_nonce_and_id(&props.db, &pubkey).await? {
-        Some((id, _)) => {
-            verify_integrity(&props.db, &props.actors.key_holder, &pubkey).await?;
+    let client_id = match get_client_id(&props.db, &pubkey).await? {
+        Some(id) => {
+            verify_integrity(&props.db, &props.actors.vault, &pubkey).await?;
            id
        }
        None => {
@@ -403,13 +343,14 @@ where
                },
            )
            .await?;
-            insert_client(&props.db, &props.actors.key_holder, &pubkey, &metadata).await?
+            insert_client(&props.db, &props.actors.vault, &pubkey, &metadata).await?
        }
    };

    sync_client_metadata(&props.db, client_id, &metadata).await?;
-    let challenge_nonce = create_nonce(&props.db, &props.actors.key_holder, &pubkey).await?;
-    challenge_client(transport, pubkey, challenge_nonce).await?;
+
+    let challenge = AuthChallenge::generate(&mut rand::rng());
+    challenge_client(transport, pubkey, challenge).await?;

    transport
        .send(Ok(Outbound::AuthSuccess))
--- a/server/crates/arbiter-server/src/actors/client/mod.rs
+++ b/server/crates/arbiter-server/src/actors/client/mod.rs
@@ -1,24 +1,22 @@
+use crate::{
+    actors::GlobalActors, crypto::integrity::Integrable, db, peers::client::session::ClientSession,
+};
 use arbiter_crypto::authn;
+use arbiter_macros::Hashable;
 use arbiter_proto::{ClientMetadata, transport::Bi};
+
 use kameo::actor::Spawn;
 use tracing::{error, info};

-use crate::{
-    actors::{GlobalActors, client::session::ClientSession},
-    crypto::integrity::Integrable,
-    db,
-};
-
 #[derive(Debug, Clone)]
 pub struct ClientProfile {
    pub pubkey: authn::PublicKey,
    pub metadata: ClientMetadata,
 }

-#[derive(arbiter_macros::Hashable)]
+#[derive(Hashable)]
 pub struct ClientCredentials {
    pub pubkey: authn::PublicKey,
-    pub nonce: i32,
 }

 impl Integrable for ClientCredentials {
--- a/server/crates/arbiter-server/src/actors/client/session.rs
+++ b/server/crates/arbiter-server/src/actors/client/session.rs
@@ -1,20 +1,19 @@
-use kameo::{Actor, messages};
-use tracing::error;
-
-use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
-
+use super::ClientConnection;
 use crate::{
    actors::{
        GlobalActors,
-        client::ClientConnection,
        evm::{ClientSignTransaction, SignTransactionError},
        flow_coordinator::RegisterClient,
-        keyholder::KeyHolderState,
+        vault::VaultState,
    },
    db,
    evm::VetError,
 };

+use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
+use kameo::{Actor, messages};
+use tracing::error;
+
 pub struct ClientSession {
    props: ClientConnection,
    client_id: i32,
@@ -29,13 +28,13 @@ impl ClientSession {
 #[messages]
 impl ClientSession {
    #[message]
-    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<KeyHolderState, Error> {
-        use crate::actors::keyholder::GetState;
+    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<VaultState, Error> {
+        use crate::actors::vault::GetState;

-        let vault_state = match self.props.actors.key_holder.ask(GetState {}).await {
+        let vault_state = match self.props.actors.vault.ask(GetState {}).await {
            Ok(state) => state,
            Err(err) => {
-                error!(?err, actor = "client", "keyholder.query.failed");
+                error!(?err, actor = "client", "vault.query.failed");
                return Err(Error::Internal);
            }
        };
--- a/server/crates/arbiter-server/src/peers/mod.rs
+++ b/server/crates/arbiter-server/src/peers/mod.rs
@@ -0,0 +1,2 @@
+pub mod client;
+pub mod user_agent;
--- a/server/crates/arbiter-server/src/peers/user_agent/auth/mod.rs
+++ b/server/crates/arbiter-server/src/peers/user_agent/auth/mod.rs
@@ -1,13 +1,11 @@
-use arbiter_crypto::authn;
+use super::{Credentials, UserAgentConnection};
+use arbiter_crypto::authn::{self, AuthChallenge};
 use arbiter_proto::transport::Bi;
+
+use state::*;
 use tracing::error;

-use crate::actors::user_agent::{
-    UserAgentConnection,
-    auth::state::{AuthContext, AuthStateMachine},
-};
 mod state;
-use state::*;

 #[derive(Debug, Clone)]
 pub enum Inbound {
@@ -46,7 +44,7 @@ impl From<diesel::result::Error> for Error {

 #[derive(Debug, Clone)]
 pub enum Outbound {
-    AuthChallenge { nonce: i32 },
+    AuthChallenge { challenge: AuthChallenge },
    AuthSuccess,
 }

@@ -54,12 +52,11 @@ fn parse_auth_event(payload: Inbound) -> AuthEvents {
    match payload {
        Inbound::AuthChallengeRequest {
            pubkey,
-            bootstrap_token: None,
-        } => AuthEvents::AuthRequest(ChallengeRequest { pubkey }),
-        Inbound::AuthChallengeRequest {
+            bootstrap_token,
+        } => AuthEvents::AuthRequest(ChallengeRequest {
            pubkey,
-            bootstrap_token: Some(token),
-        } => AuthEvents::BootstrapAuthRequest(BootstrapAuthRequest { pubkey, token }),
+            bootstrap_token,
+        }),
        Inbound::AuthChallengeSolution { signature } => {
            AuthEvents::ReceivedSolution(ChallengeSolution {
                solution: signature,
@@ -70,21 +67,20 @@ fn parse_auth_event(payload: Inbound) -> AuthEvents {

 pub async fn authenticate<T>(
    props: &mut UserAgentConnection,
-    transport: T,
-) -> Result<authn::PublicKey, Error>
+    transport: &mut T,
+) -> Result<Credentials, Error>
 where
-    T: Bi<Inbound, Result<Outbound, Error>> + Send,
+    T: Bi<Inbound, Result<Outbound, Error>> + Send + ?Sized,
 {
    let mut state = AuthStateMachine::new(AuthContext::new(props, transport));

    loop {
-        // `state` holds a mutable reference to `props` so we can't access it directly here
        let Some(payload) = state.context_mut().transport.recv().await else {
            return Err(Error::Transport);
        };

        match state.process_event(parse_auth_event(payload)).await {
-            Ok(AuthStates::AuthOk(key)) => return Ok(key.clone()),
+            Ok(AuthStates::AuthOk(result)) => return Ok(result.clone()),
            Err(AuthError::ActionFailed(err)) => {
                error!(?err, "State machine action failed");
                return Err(err);
--- a/server/crates/arbiter-server/src/peers/user_agent/auth/state.rs
+++ b/server/crates/arbiter-server/src/peers/user_agent/auth/state.rs
@@ -0,0 +1,198 @@
+use super::{
+    super::{Credentials, UserAgentConnection},
+    Error,
+};
+use crate::{
+    actors::bootstrap::ConsumeToken,
+    db::{DatabasePool, schema::useragent_client},
+    peers::user_agent::auth::Outbound,
+};
+use arbiter_crypto::authn::{self, AuthChallenge, USERAGENT_CONTEXT};
+use arbiter_proto::transport::Bi;
+
+use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl};
+use diesel_async::RunQueryDsl;
+use tracing::error;
+
+pub(super) struct ChallengeRequest {
+    pub(super) pubkey: authn::PublicKey,
+    pub(super) bootstrap_token: Option<String>,
+}
+
+pub(super) struct ChallengeContext {
+    pub(super) challenge: AuthChallenge,
+    pub(super) pubkey: authn::PublicKey,
+    pub(super) bootstrap_token: Option<String>,
+}
+
+pub(super) struct ChallengeSolution {
+    pub(super) solution: Vec<u8>,
+}
+
+smlang::statemachine!(
+    name: Auth,
+    custom_error: true,
+    transitions: {
+        *Init + AuthRequest(ChallengeRequest) / async prepare_challenge = SentChallenge(ChallengeContext),
+        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) / async verify_solution = AuthOk(Credentials),
+    }
+);
+
+async fn get_client_id(db: &DatabasePool, pubkey: &authn::PublicKey) -> Result<Option<i32>, Error> {
+    let mut conn = db.get().await.map_err(|e| {
+        error!(error = ?e, "Database pool error");
+        Error::internal("Database unavailable")
+    })?;
+
+    useragent_client::table
+        .filter(useragent_client::public_key.eq(pubkey.to_bytes()))
+        .select(useragent_client::id)
+        .first::<i32>(&mut conn)
+        .await
+        .optional()
+        .map_err(|e| {
+            error!(error = ?e, "Database error");
+            Error::internal("Database operation failed")
+        })
+}
+
+async fn register_key(db: &DatabasePool, pubkey: &authn::PublicKey) -> Result<i32, Error> {
+    let pubkey_bytes = pubkey.to_bytes();
+    let mut conn = db.get().await.map_err(|e| {
+        error!(error = ?e, "Database pool error");
+        Error::internal("Database unavailable")
+    })?;
+
+    let id: i32 = diesel::insert_into(useragent_client::table)
+        .values((useragent_client::public_key.eq(pubkey_bytes),))
+        .returning(useragent_client::id)
+        .get_result(&mut conn)
+        .await
+        .map_err(|e| {
+            error!(error = ?e, "Database error");
+            Error::internal("Database operation failed")
+        })?;
+
+    Ok(id)
+}
+
+pub(super) struct AuthContext<'a, T: ?Sized> {
+    pub(super) conn: &'a mut UserAgentConnection,
+    pub(super) transport: &'a mut T,
+}
+
+impl<'a, T: ?Sized> AuthContext<'a, T> {
+    pub(super) fn new(conn: &'a mut UserAgentConnection, transport: &'a mut T) -> Self {
+        Self { conn, transport }
+    }
+}
+
+impl<T> AuthStateMachineContext for AuthContext<'_, T>
+where
+    T: Bi<super::Inbound, Result<super::Outbound, Error>> + Send + ?Sized,
+{
+    type Error = Error;
+
+    async fn prepare_challenge(
+        &mut self,
+        ChallengeRequest {
+            pubkey,
+            bootstrap_token,
+        }: ChallengeRequest,
+    ) -> Result<ChallengeContext, Self::Error> {
+        // Verify pubkey is registered (unless bootstrapping)
+        if bootstrap_token.is_none() {
+            let id = get_client_id(&self.conn.db, &pubkey).await?;
+            if id.is_none() {
+                return Err(Error::UnregisteredPublicKey);
+            }
+        }
+
+        let challenge = AuthChallenge::generate(&mut rand::rng());
+
+        self.transport
+            .send(Ok(Outbound::AuthChallenge {
+                challenge: challenge.clone(),
+            }))
+            .await
+            .map_err(|e| {
+                error!(?e, "Failed to send auth challenge");
+                Error::Transport
+            })?;
+
+        Ok(ChallengeContext {
+            challenge,
+            pubkey,
+            bootstrap_token,
+        })
+    }
+
+    #[allow(missing_docs)]
+    #[allow(clippy::unused_unit)]
+    async fn verify_solution(
+        &mut self,
+        ChallengeContext {
+            challenge,
+            pubkey,
+            bootstrap_token,
+        }: &ChallengeContext,
+        ChallengeSolution { solution }: ChallengeSolution,
+    ) -> Result<Credentials, Self::Error> {
+        let signature = authn::Signature::try_from(solution.as_slice()).map_err(|_| {
+            error!("Failed to decode signature in challenge solution");
+            Error::InvalidChallengeSolution
+        })?;
+
+        let valid = pubkey.verify(challenge, USERAGENT_CONTEXT, &signature);
+
+        if !valid {
+            self.transport
+                .send(Err(Error::InvalidChallengeSolution))
+                .await
+                .map_err(|_| Error::Transport)?;
+            return Err(Error::InvalidChallengeSolution);
+        }
+
+        // Resolve client id: bootstrap (consume token + register) or lookup
+        let id = match bootstrap_token {
+            Some(token) => {
+                let token_ok: bool = self
+                    .conn
+                    .actors
+                    .bootstrapper
+                    .ask(ConsumeToken {
+                        token: token.clone(),
+                    })
+                    .await
+                    .map_err(|e| {
+                        error!(?e, "Failed to consume bootstrap token");
+                        Error::internal("Failed to consume bootstrap token")
+                    })?;
+
+                if !token_ok {
+                    error!("Invalid bootstrap token provided");
+                    self.transport
+                        .send(Err(Error::InvalidBootstrapToken))
+                        .await
+                        .map_err(|_| Error::Transport)?;
+                    return Err(Error::InvalidBootstrapToken);
+                }
+
+                register_key(&self.conn.db, pubkey).await?
+            }
+            None => get_client_id(&self.conn.db, pubkey)
+                .await?
+                .ok_or(Error::UnregisteredPublicKey)?,
+        };
+
+        self.transport
+            .send(Ok(Outbound::AuthSuccess))
+            .await
+            .map_err(|_| Error::Transport)?;
+
+        Ok(Credentials {
+            id,
+            pubkey: pubkey.clone(),
+        })
+    }
+}
--- a/server/crates/arbiter-server/src/peers/user_agent/mod.rs
+++ b/server/crates/arbiter-server/src/peers/user_agent/mod.rs
@@ -0,0 +1,185 @@
+use crate::{
+    actors::{
+        GlobalActors,
+        vault::{GetState, Vault},
+    },
+    crypto::integrity::{self, AttestationStatus, Integrable},
+    db::{self, DatabaseError, DatabasePool},
+    peers::client::ClientProfile,
+};
+use arbiter_crypto::authn;
+use arbiter_macros::Hashable;
+use arbiter_proto::transport::{Bi, Sender};
+use vault_gate::VaultGate;
+
+use kameo::actor::{ActorRef, Spawn as _};
+use tokio::sync::oneshot;
+use tracing::{error, warn};
+
+pub use auth::authenticate;
+pub use session::UserAgentSession;
+
+pub mod auth;
+pub mod session;
+pub mod vault_gate;
+
+#[derive(Debug, Clone, Hashable)]
+pub struct Credentials {
+    pub id: i32,
+    pub pubkey: authn::PublicKey,
+}
+
+impl Integrable for Credentials {
+    const KIND: &'static str = "useragent_credentials";
+}
+
+// Messages, sent by user agent to connection client without having a request
+#[derive(Debug)]
+pub enum OutOfBand {
+    ClientConnectionRequest { profile: ClientProfile },
+    ClientConnectionCancel { pubkey: authn::PublicKey },
+}
+
+#[derive(Clone)]
+pub struct UserAgentConnection {
+    pub(crate) db: db::DatabasePool,
+    pub(crate) actors: GlobalActors,
+}
+
+impl UserAgentConnection {
+    pub fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
+        Self { db, actors }
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("authentication failed: {0:?}")]
+    Auth(auth::Error),
+    #[error("vault gate failed: {0}")]
+    VaultGate(#[from] vault_gate::Error),
+    #[error("transport closed unexpectedly")]
+    Transport,
+    #[error("database error: {0}")]
+    Database(DatabaseError),
+    #[error("internal: {0}")]
+    Internal(String),
+}
+
+impl From<auth::Error> for Error {
+    fn from(err: auth::Error) -> Self {
+        Self::Auth(err)
+    }
+}
+
+async fn verify_integrity(
+    db: &DatabasePool,
+    vault: &ActorRef<Vault>,
+    credentials: &Credentials,
+) -> Result<(), Error> {
+    let mut conn = db
+        .get()
+        .await
+        .map_err(|_| Error::Internal("DB unavailable".into()))?;
+    match integrity::verify_entity(&mut conn, &vault, credentials, credentials.id).await {
+        Ok(AttestationStatus::Attested) => Ok(()),
+        Ok(AttestationStatus::Unavailable) => {
+            Err(Error::Internal("Vault sealed during promotion".into()))
+        }
+        Err(e) => {
+            error!(?e, "Integrity verification failed during unseal promotion");
+            Err(Error::Internal("Integrity check failed".into()))
+        }
+    }
+}
+
+async fn should_run_gate(vault: &ActorRef<Vault>) -> Result<bool, Error> {
+    let vault_state = vault
+        .ask(GetState {})
+        .await
+        .map_err(|_| Error::Internal("Failed to contact the vault".into()))?;
+
+    Ok(!matches!(
+        vault_state,
+        crate::actors::vault::VaultState::Unsealed
+    ))
+}
+
+async fn run_vault_gate<T>(
+    props: &UserAgentConnection,
+    transport: &mut T,
+    auth_creds: Credentials,
+) -> Result<(), Error>
+where
+    T: Bi<vault_gate::Inbound, Result<vault_gate::Outbound, vault_gate::Error>> + Send + ?Sized,
+{
+    let (promotion_tx, mut promotion_rx) = oneshot::channel();
+    let gate = VaultGate::spawn(VaultGate::new(
+        auth_creds,
+        props.actors.clone(),
+        props.db.clone(),
+        promotion_tx,
+    ));
+
+    let result = loop {
+        tokio::select! {
+            promotion = &mut promotion_rx => {
+                break match promotion {
+                    Ok(Ok(creds)) => Ok(creds),
+                    Ok(Err(err)) => Err(Error::VaultGate(err)),
+                    Err(_) => Err(Error::Internal(
+                        "vault gate promotion channel closed".into(),
+                    )),
+                };
+            }
+
+            inbound = transport.recv() => {
+                let Some(inbound) = inbound else {
+                    break Err(Error::Transport);
+                };
+
+                match gate.ask(inbound).await {
+                    Ok(outbound) => {
+                        if transport.send(Ok(outbound)).await.is_err() {
+                            break Err(Error::Transport);
+                        }
+                    }
+                    Err(err) => {
+                        warn!(?err, "VaultGate failed to handle message");
+                        break Err(Error::Internal(format!(
+                            "vault gate ask failed: {err:?}"
+                        )));
+                    }
+                }
+            }
+        }
+    };
+
+    gate.kill();
+    result
+}
+
+pub async fn start<T>(
+    props: &mut UserAgentConnection,
+    mut transport: T,
+    oob_sender: Box<dyn Sender<OutOfBand>>,
+) -> Result<ActorRef<UserAgentSession>, Error>
+where
+    T: Bi<auth::Inbound, Result<auth::Outbound, auth::Error>> + Send,
+    T: Bi<vault_gate::Inbound, Result<vault_gate::Outbound, vault_gate::Error>> + Send,
+{
+    let creds = authenticate(props, &mut transport).await?;
+
+    // should run vault gate only if sealed / unbootstrapped
+    if should_run_gate(&props.actors.vault).await? {
+        run_vault_gate(props, &mut transport, creds.clone()).await?;
+    }
+
+    // checking the integrity
+    verify_integrity(&props.db, &props.actors.vault, &creds).await?;
+
+    Ok(UserAgentSession::spawn(UserAgentSession::new(
+        props.clone(),
+        oob_sender,
+    )))
+}
--- a/server/crates/arbiter-server/src/peers/user_agent/session/handlers.rs
+++ b/server/crates/arbiter-server/src/peers/user_agent/session/handlers.rs
@@ -0,0 +1,283 @@
+use super::{Error, UserAgentSession};
+use crate::{
+    actors::evm::{
+        ClientSignTransaction, Generate, ListWallets, SignTransactionError as EvmSignError,
+        UseragentCreateGrant, UseragentListGrants,
+    },
+    actors::flow_coordinator::client_connect_approval::ClientApprovalAnswer,
+    actors::vault::VaultState,
+    db::models::{EvmWalletAccess, NewEvmWalletAccess, ProgramClient, ProgramClientMetadata},
+    evm::policies::{Grant, SpecificGrant},
+};
+use arbiter_crypto::authn;
+
+use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
+use diesel::{ExpressionMethods as _, QueryDsl as _, SelectableHelper};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use kameo::{error::SendError, messages, prelude::Context};
+use tracing::error;
+
+#[derive(Debug, Error)]
+pub enum SignTransactionError {
+    #[error("Policy evaluation failed")]
+    Vet(#[from] crate::evm::VetError),
+
+    #[error("Internal signing error")]
+    Internal,
+}
+
+#[derive(Debug, Error)]
+pub enum GrantMutationError {
+    #[error("Vault is sealed")]
+    VaultSealed,
+
+    #[error("Internal grant mutation error")]
+    Internal,
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message]
+    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<VaultState, Error> {
+        use crate::actors::vault::GetState;
+
+        let vault_state = match self.props.actors.vault.ask(GetState {}).await {
+            Ok(state) => state,
+            Err(err) => {
+                error!(?err, actor = "useragent", "vault.query.failed");
+                return Err(Error::internal("Vault is in broken state"));
+            }
+        };
+
+        Ok(vault_state)
+    }
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message]
+    pub(crate) async fn handle_evm_wallet_create(&mut self) -> Result<(i32, Address), Error> {
+        match self.props.actors.evm.ask(Generate {}).await {
+            Ok(address) => Ok(address),
+            Err(SendError::HandlerError(err)) => Err(Error::internal(format!(
+                "EVM wallet generation failed: {err}"
+            ))),
+            Err(err) => {
+                error!(?err, "EVM actor unreachable during wallet create");
+                Err(Error::internal("EVM actor unreachable"))
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_evm_wallet_list(&mut self) -> Result<Vec<(i32, Address)>, Error> {
+        match self.props.actors.evm.ask(ListWallets {}).await {
+            Ok(wallets) => Ok(wallets),
+            Err(err) => {
+                error!(?err, "EVM wallet list failed");
+                Err(Error::internal("Failed to list EVM wallets"))
+            }
+        }
+    }
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message]
+    pub(crate) async fn handle_grant_list(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
+        match self.props.actors.evm.ask(UseragentListGrants {}).await {
+            Ok(grants) => Ok(grants),
+            Err(err) => {
+                error!(?err, "EVM grant list failed");
+                Err(Error::internal("Failed to list EVM grants"))
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_grant_create(
+        &mut self,
+        basic: crate::evm::policies::SharedGrantSettings,
+        grant: 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)
+    }
+}
--- a/server/crates/arbiter-server/src/peers/user_agent/session/mod.rs
+++ b/server/crates/arbiter-server/src/peers/user_agent/session/mod.rs
@@ -1,21 +1,19 @@
+use super::{OutOfBand, UserAgentConnection};
+use crate::{
+    actors::{
+        flow_coordinator::client_connect_approval::ClientApprovalController,
+        useragent_registry::ConnectUseragent,
+    },
+    peers::client::ClientProfile,
+};
 use arbiter_crypto::authn;
-
-use std::{borrow::Cow, collections::HashMap};
-
 use arbiter_proto::transport::Sender;
-use async_trait::async_trait;
+
 use kameo::{Actor, actor::ActorRef, messages};
+use std::{borrow::Cow, collections::HashMap};
 use thiserror::Error;
 use tracing::error;

-use crate::actors::{
-    client::ClientProfile,
-    flow_coordinator::{RegisterUserAgent, client_connect_approval::ClientApprovalController},
-    user_agent::{OutOfBand, UserAgentConnection},
-};
-mod state;
-use state::{DummyContext, UserAgentEvents, UserAgentStateMachine};
-
 #[derive(Debug, Error)]
 pub enum Error {
    #[error("State transition failed")]
@@ -53,47 +51,21 @@ pub struct PendingClientApproval {

 pub struct UserAgentSession {
    props: UserAgentConnection,
-    state: UserAgentStateMachine<DummyContext>,
    sender: Box<dyn Sender<OutOfBand>>,

    pending_client_approvals: HashMap<Vec<u8>, PendingClientApproval>,
 }

-pub mod connection;
+pub mod handlers;

 impl UserAgentSession {
    pub(crate) fn new(props: UserAgentConnection, sender: Box<dyn Sender<OutOfBand>>) -> Self {
        Self {
            props,
-            state: UserAgentStateMachine::new(DummyContext),
            sender,
            pending_client_approvals: Default::default(),
        }
    }
-
-    pub fn new_test(db: crate::db::DatabasePool, actors: crate::actors::GlobalActors) -> Self {
-        struct DummySender;
-
-        #[async_trait]
-        impl Sender<OutOfBand> for DummySender {
-            async fn send(
-                &mut self,
-                _item: OutOfBand,
-            ) -> Result<(), arbiter_proto::transport::Error> {
-                Ok(())
-            }
-        }
-
-        Self::new(UserAgentConnection::new(db, actors), Box::new(DummySender))
-    }
-
-    fn transition(&mut self, event: UserAgentEvents) -> Result<(), Error> {
-        self.state.process_event(event).map_err(|e| {
-            error!(?e, "State transition failed");
-            Error::State
-        })?;
-        Ok(())
-    }
 }

 #[messages]
@@ -140,17 +112,17 @@ impl Actor for UserAgentSession {
    ) -> Result<Self, Self::Error> {
        args.props
            .actors
-            .flow_coordinator
-            .ask(RegisterUserAgent {
+            .useragent_registry
+            .ask(ConnectUseragent {
                actor: this.clone(),
            })
            .await
            .map_err(|err| {
                error!(
                    ?err,
-                    "Failed to register user agent connection with flow coordinator"
+                    "Failed to register user agent connection with user agent registry"
                );
-                Error::internal("Failed to register user agent connection with flow coordinator")
+                Error::internal("Failed to register user agent connection with user agent registry")
            })?;
        Ok(args)
    }
--- a/server/crates/arbiter-server/src/peers/user_agent/vault_gate/mod.rs
+++ b/server/crates/arbiter-server/src/peers/user_agent/vault_gate/mod.rs
@@ -0,0 +1,294 @@
+use super::Credentials;
+use crate::{
+    actors::{
+        GlobalActors,
+        vault::{self, Bootstrap, GetState, TryUnseal, VaultState, events},
+    },
+    crypto::integrity::{self},
+    db::DatabasePool,
+};
+use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use state::*;
+
+use chacha20poly1305::{AeadInPlace, KeyInit as _, XChaCha20Poly1305, XNonce};
+use kameo::{Actor, error::SendError, messages, prelude::Message};
+use kameo_actors::message_bus::Register;
+use tokio::sync::oneshot;
+use tracing::{error, info};
+use x25519_dalek::{EphemeralSecret, PublicKey, SharedSecret};
+
+pub mod state;
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("Vault is already bootstrapped")]
+    AlreadyBootstrapped,
+    #[error("Invalid key provided")]
+    InvalidKey,
+
+    #[error("State transition failed")]
+    State,
+
+    #[error("Internal error: {0}")]
+    Internal(String),
+}
+impl Error {
+    fn internal(message: impl Into<String>) -> Self {
+        Self::Internal(message.into())
+    }
+}
+
+pub struct HandshakeResponse {
+    pub server_pubkey: PublicKey,
+}
+
+pub struct VaultGate {
+    pub auth_creds: Credentials,
+    pub promotion_tx: Option<oneshot::Sender<Result<(), Error>>>,
+    pub state: State,
+    pub actors: GlobalActors,
+    pub db: DatabasePool,
+}
+
+impl VaultGate {
+    pub fn new(
+        auth_creds: Credentials,
+        actors: GlobalActors,
+        db: DatabasePool,
+        promotion_tx: oneshot::Sender<Result<(), Error>>,
+    ) -> Self {
+        Self {
+            auth_creds,
+            state: State::default(),
+            actors,
+            db,
+            promotion_tx: Some(promotion_tx),
+        }
+    }
+}
+
+impl Actor for VaultGate {
+    type Args = Self;
+
+    type Error = ();
+
+    async fn on_start(
+        args: Self::Args,
+        actor_ref: kameo::prelude::ActorRef<Self>,
+    ) -> Result<Self, Self::Error> {
+        let _ = args
+            .actors
+            .events
+            .tell(Register(
+                actor_ref.clone().recipient::<events::Bootstrapped>(),
+            ))
+            .await;
+        let _ = args
+            .actors
+            .events
+            .tell(Register(actor_ref.recipient::<events::Unsealed>()))
+            .await;
+        Ok(args)
+    }
+}
+
+impl VaultGate {
+    fn decrypt_key(
+        secret: &SharedSecret,
+        nonce: &[u8],
+        ciphertext: &[u8],
+        associated_data: &[u8],
+    ) -> Result<SafeCell<Vec<u8>>, ()> {
+        let nonce = XNonce::from_slice(nonce);
+
+        let cipher = XChaCha20Poly1305::new(secret.as_bytes().into());
+
+        let mut key_buffer = SafeCell::new(ciphertext.to_vec());
+
+        let decryption_result = key_buffer.write_inline(|write_handle| {
+            cipher.decrypt_in_place(nonce, associated_data, write_handle)
+        });
+
+        match decryption_result {
+            Ok(_) => Ok(key_buffer),
+            Err(err) => {
+                error!(?err, "Failed to decrypt encrypted key material");
+                Err(())
+            }
+        }
+    }
+}
+
+#[messages(messages = Inbound, replies = Outbound)]
+impl VaultGate {
+    #[message]
+    pub async fn handle_handshake(
+        &mut self,
+        client_pubkey: x25519_dalek::PublicKey,
+    ) -> Result<HandshakeResponse, Error> {
+        let ephemeral_secret = EphemeralSecret::random();
+        let public_key = PublicKey::from(&ephemeral_secret);
+
+        let secret = ephemeral_secret.diffie_hellman(&client_pubkey);
+
+        self.state = State::ReadyForExchange {
+            server_key: public_key.clone(),
+            secret,
+        };
+
+        Ok(HandshakeResponse {
+            server_pubkey: public_key,
+        })
+    }
+
+    #[message]
+    pub async fn handle_unseal_encrypted_key(
+        &mut self,
+        nonce: Vec<u8>,
+        ciphertext: Vec<u8>,
+        associated_data: Vec<u8>,
+    ) -> Result<(), Error> {
+        let State::ReadyForExchange { secret, .. } = &self.state else {
+            return Err(Error::State);
+        };
+
+        let seal_key_buffer = match Self::decrypt_key(secret, &nonce, &ciphertext, &associated_data)
+        {
+            Ok(buffer) => buffer,
+            Err(()) => {
+                return Err(Error::InvalidKey);
+            }
+        };
+
+        match self
+            .actors
+            .vault
+            .ask(TryUnseal {
+                seal_key_raw: seal_key_buffer,
+            })
+            .await
+        {
+            Ok(_) => {
+                info!("Successfully unsealed key with client-provided key");
+                Ok(())
+            }
+            Err(SendError::HandlerError(vault::Error::InvalidKey)) => Err(Error::InvalidKey),
+            Err(SendError::HandlerError(err)) => {
+                error!(?err, "Vault failed to unseal key");
+                Err(Error::InvalidKey)
+            }
+            Err(err) => {
+                error!(?err, "Failed to send unseal request to vault");
+                Err(Error::internal("Vault actor error").into())
+            }
+        }
+    }
+
+    #[message]
+    pub async fn handle_bootstrap_encrypted_key(
+        &mut self,
+        nonce: Vec<u8>,
+        ciphertext: Vec<u8>,
+        associated_data: Vec<u8>,
+    ) -> Result<(), Error> {
+        let State::ReadyForExchange { secret, .. } = &self.state else {
+            return Err(Error::State);
+        };
+
+        let seal_key_buffer = match Self::decrypt_key(secret, &nonce, &ciphertext, &associated_data)
+        {
+            Ok(buffer) => buffer,
+            Err(()) => {
+                return Err(Error::InvalidKey);
+            }
+        };
+
+        match self
+            .actors
+            .vault
+            .ask(Bootstrap {
+                seal_key_raw: seal_key_buffer,
+            })
+            .await
+        {
+            Ok(_) => {
+                info!("Successfully bootstrapped vault with client-provided key");
+                Ok(())
+            }
+            Err(SendError::HandlerError(vault::Error::AlreadyBootstrapped)) => {
+                Err(Error::AlreadyBootstrapped)
+            }
+            Err(SendError::HandlerError(err)) => {
+                error!(?err, "Vault failed to bootstrap vault");
+                Err(Error::InvalidKey)
+            }
+            Err(err) => {
+                error!(?err, "Failed to send bootstrap request to vault");
+                Err(Error::internal("Vault error"))
+            }
+        }
+    }
+
+    #[message]
+    pub async fn handle_vault_state(&mut self) -> Result<VaultState, Error> {
+        let answer = self
+            .actors
+            .vault
+            .ask(GetState {})
+            .await
+            .map_err(|_| Error::internal("failed to query vault"))?;
+
+        Ok(answer)
+    }
+}
+
+impl Message<events::Bootstrapped> for VaultGate {
+    type Reply = ();
+
+    async fn handle(
+        &mut self,
+        _: events::Bootstrapped,
+        ctx: &mut kameo::prelude::Context<Self, Self::Reply>,
+    ) -> Self::Reply {
+        let result = async {
+            let mut conn = self
+                .db
+                .get()
+                .await
+                .map_err(|_| Error::internal("DB unavailable"))?;
+            integrity::sign_entity(
+                &mut conn,
+                &self.actors.vault,
+                &self.auth_creds,
+                self.auth_creds.id,
+            )
+            .await
+            .map_err(|e| {
+                error!(?e, "Failed to sign integrity envelope on bootstrap");
+                Error::internal("Integrity sign failed")
+            })?;
+            Ok(())
+        }
+        .await;
+
+        if let Some(tx) = self.promotion_tx.take() {
+            let _ = tx.send(result);
+        }
+        ctx.stop();
+    }
+}
+
+impl Message<events::Unsealed> for VaultGate {
+    type Reply = ();
+
+    async fn handle(
+        &mut self,
+        _: events::Unsealed,
+        ctx: &mut kameo::prelude::Context<Self, Self::Reply>,
+    ) -> Self::Reply {
+        if let Some(tx) = self.promotion_tx.take() {
+            let _ = tx.send(Ok(()));
+        }
+        ctx.stop();
+    }
+}
--- a/server/crates/arbiter-server/src/peers/user_agent/vault_gate/state.rs
+++ b/server/crates/arbiter-server/src/peers/user_agent/vault_gate/state.rs
@@ -0,0 +1,11 @@
+use x25519_dalek::{PublicKey, SharedSecret};
+
+#[derive(Default)]
+pub enum State {
+    #[default]
+    Idle,
+    ReadyForExchange {
+        server_key: PublicKey,
+        secret: SharedSecret,
+    },
+}
--- a/server/crates/arbiter-server/tests/client/auth.rs
+++ b/server/crates/arbiter-server/tests/client/auth.rs
@@ -1,24 +1,23 @@
+use super::common::ChannelTransport;
 use arbiter_crypto::{
-    authn::{self, CLIENT_CONTEXT, format_challenge},
+    authn::{self, AuthChallenge, CLIENT_CONTEXT},
    safecell::{SafeCell, SafeCellHandle as _},
 };
-use arbiter_proto::ClientMetadata;
-use arbiter_proto::transport::{Receiver, Sender};
+use arbiter_proto::{
+    ClientMetadata,
+    transport::{Receiver, Sender},
+};
 use arbiter_server::{
-    actors::{
-        GlobalActors,
-        client::{ClientConnection, ClientCredentials, auth, connect_client},
-        keyholder::Bootstrap,
-    },
+    actors::{GlobalActors, vault::Bootstrap},
    crypto::integrity,
    db::{self, schema},
+    peers::client::{ClientConnection, ClientCredentials, auth, connect_client},
 };
+
 use diesel::{ExpressionMethods as _, NullableExpressionMethods as _, QueryDsl as _, insert_into};
 use diesel_async::RunQueryDsl;
 use ml_dsa::{KeyGen, MlDsa87, SigningKey, VerifyingKey, signature::Keypair as _};

-use super::common::ChannelTransport;
-
 fn metadata(name: &str, description: Option<&str>, version: Option<&str>) -> ClientMetadata {
    ClientMetadata {
        name: name.to_owned(),
@@ -58,10 +57,9 @@ async fn insert_registered_client(

    integrity::sign_entity(
        &mut conn,
-        &actors.key_holder,
+        &actors.vault,
        &ClientCredentials {
            pubkey: pubkey.into(),
-            nonce: 1,
        },
        client_id,
    )
@@ -69,12 +67,8 @@ async fn insert_registered_client(
    .unwrap();
 }

-fn sign_client_challenge(
-    key: &SigningKey<MlDsa87>,
-    nonce: i32,
-    pubkey: &authn::PublicKey,
-) -> authn::Signature {
-    let challenge = format_challenge(nonce, &pubkey.to_bytes());
+fn sign_client_challenge(key: &SigningKey<MlDsa87>, challenge: &AuthChallenge) -> authn::Signature {
+    let challenge = challenge.format();
    key.signing_key()
        .sign_deterministic(&challenge, CLIENT_CONTEXT)
        .unwrap()
@@ -89,10 +83,7 @@ async fn insert_bootstrap_sentinel_useragent(db: &db::DatabasePool) {
        .to_vec();

    insert_into(schema::useragent_client::table)
-        .values((
-            schema::useragent_client::public_key.eq(sentinel_key),
-            schema::useragent_client::key_type.eq(1i32),
-        ))
+        .values((schema::useragent_client::public_key.eq(sentinel_key),))
        .execute(&mut conn)
        .await
        .unwrap();
@@ -103,7 +94,7 @@ async fn spawn_test_actors(db: &db::DatabasePool) -> GlobalActors {

    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
    actors
-        .key_holder
+        .vault
        .ask(Bootstrap {
            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
        })
@@ -114,7 +105,7 @@ async fn spawn_test_actors(db: &db::DatabasePool) -> GlobalActors {

 #[tokio::test]
 #[test_log::test]
-pub async fn test_unregistered_pubkey_rejected() {
+async fn test_unregistered_pubkey_rejected() {
    let db = db::create_test_pool().await;

    let (server_transport, mut test_transport) = ChannelTransport::new();
@@ -141,7 +132,7 @@ pub async fn test_unregistered_pubkey_rejected() {

 #[tokio::test]
 #[test_log::test]
-pub async fn test_challenge_auth() {
+async fn test_challenge_auth() {
    let db = db::create_test_pool().await;
    let actors = spawn_test_actors(&db).await;

@@ -178,14 +169,14 @@ pub async fn test_challenge_auth() {
        .expect("should receive challenge");
    let challenge = match response {
        Ok(resp) => match resp {
-            auth::Outbound::AuthChallenge { pubkey, nonce } => (pubkey, nonce),
+            auth::Outbound::AuthChallenge { challenge } => challenge,
            other => panic!("Expected AuthChallenge, got {other:?}"),
        },
        Err(err) => panic!("Expected Ok response, got Err({err:?})"),
    };

    // Sign the challenge and send solution
-    let signature = sign_client_challenge(&new_key, challenge.1, &challenge.0);
+    let signature = sign_client_challenge(&new_key, &challenge);

    test_transport
        .send(auth::Inbound::AuthChallengeSolution { signature })
@@ -208,7 +199,7 @@ pub async fn test_challenge_auth() {

 #[tokio::test]
 #[test_log::test]
-pub async fn test_metadata_unchanged_does_not_append_history() {
+async fn test_metadata_unchanged_does_not_append_history() {
    let db = db::create_test_pool().await;
    let actors = spawn_test_actors(&db).await;
    let new_key = MlDsa87::key_gen(&mut rand::rng());
@@ -233,11 +224,11 @@ pub async fn test_metadata_unchanged_does_not_append_history() {
        .unwrap();

    let response = test_transport.recv().await.unwrap().unwrap();
-    let (pubkey, nonce) = match response {
-        auth::Outbound::AuthChallenge { pubkey, nonce } => (pubkey, nonce),
+    let challenge = match response {
+        auth::Outbound::AuthChallenge { challenge } => challenge,
        other => panic!("Expected AuthChallenge, got {other:?}"),
    };
-    let signature = sign_client_challenge(&new_key, nonce, &pubkey);
+    let signature = sign_client_challenge(&new_key, &challenge);
    test_transport
        .send(auth::Inbound::AuthChallengeSolution { signature })
        .await
@@ -265,7 +256,7 @@ pub async fn test_metadata_unchanged_does_not_append_history() {

 #[tokio::test]
 #[test_log::test]
-pub async fn test_metadata_change_appends_history_and_repoints_binding() {
+async fn test_metadata_change_appends_history_and_repoints_binding() {
    let db = db::create_test_pool().await;
    let actors = spawn_test_actors(&db).await;
    let new_key = MlDsa87::key_gen(&mut rand::rng());
@@ -295,11 +286,11 @@ pub async fn test_metadata_change_appends_history_and_repoints_binding() {
        .unwrap();

    let response = test_transport.recv().await.unwrap().unwrap();
-    let (pubkey, nonce) = match response {
-        auth::Outbound::AuthChallenge { pubkey, nonce } => (pubkey, nonce),
+    let challenge = match response {
+        auth::Outbound::AuthChallenge { challenge } => challenge,
        other => panic!("Expected AuthChallenge, got {other:?}"),
    };
-    let signature = sign_client_challenge(&new_key, nonce, &pubkey);
+    let signature = sign_client_challenge(&new_key, &challenge);
    test_transport
        .send(auth::Inbound::AuthChallengeSolution { signature })
        .await
@@ -352,7 +343,7 @@ pub async fn test_metadata_change_appends_history_and_repoints_binding() {

 #[tokio::test]
 #[test_log::test]
-pub async fn test_challenge_auth_rejects_integrity_tag_mismatch() {
+async fn test_challenge_auth_rejects_integrity_tag_mismatch() {
    let db = db::create_test_pool().await;
    let actors = spawn_test_actors(&db).await;

--- a/server/crates/arbiter-server/tests/common/mod.rs
+++ b/server/crates/arbiter-server/tests/common/mod.rs
@@ -1,7 +1,7 @@
 use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_proto::transport::{Bi, Error, Receiver, Sender};
 use arbiter_server::{
-    actors::keyholder::KeyHolder,
+    actors::{GlobalActors, vault::Vault},
    db::{self, schema},
 };

@@ -11,8 +11,10 @@ use diesel_async::RunQueryDsl;
 use tokio::sync::mpsc;

 #[allow(dead_code)]
-pub async fn bootstrapped_keyholder(db: &db::DatabasePool) -> KeyHolder {
-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+pub(crate) async fn bootstrapped_vault(db: &db::DatabasePool) -> Vault {
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
    actor
        .bootstrap(SafeCell::new(b"test-seal-key".to_vec()))
        .await
@@ -21,7 +23,7 @@ pub async fn bootstrapped_keyholder(db: &db::DatabasePool) -> KeyHolder {
 }

 #[allow(dead_code)]
-pub async fn root_key_history_id(db: &db::DatabasePool) -> i32 {
+pub(crate) async fn root_key_history_id(db: &db::DatabasePool) -> i32 {
    let mut conn = db.get().await.unwrap();
    let id = schema::arbiter_settings::table
        .select(schema::arbiter_settings::root_key_id)
@@ -32,14 +34,14 @@ pub async fn root_key_history_id(db: &db::DatabasePool) -> i32 {
 }

 #[allow(dead_code)]
-pub struct ChannelTransport<T, Y> {
+pub(crate) struct ChannelTransport<T, Y> {
    receiver: mpsc::Receiver<T>,
    sender: mpsc::Sender<Y>,
 }

 impl<T, Y> ChannelTransport<T, Y> {
    #[allow(dead_code)]
-    pub fn new() -> (Self, ChannelTransport<Y, T>) {
+    pub(crate) fn new() -> (Self, ChannelTransport<Y, T>) {
        let (tx1, rx1) = mpsc::channel(10);
        let (tx2, rx2) = mpsc::channel(10);
        (
--- a/server/crates/arbiter-server/tests/keyholder.rs
+++ b/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;
--- a/server/crates/arbiter-server/tests/user_agent/auth.rs
+++ b/server/crates/arbiter-server/tests/user_agent/auth.rs
@@ -1,44 +1,157 @@
+use super::common::ChannelTransport;
 use arbiter_crypto::{
-    authn::{self, USERAGENT_CONTEXT, format_challenge},
+    authn::{self, AuthChallenge, USERAGENT_CONTEXT},
    safecell::{SafeCell, SafeCellHandle as _},
 };
-
-use arbiter_proto::transport::{Receiver, Sender};
+use arbiter_proto::transport::{Error as TransportError, Receiver, Sender};
 use arbiter_server::{
-    actors::{
-        GlobalActors,
-        bootstrap::GetToken,
-        keyholder::Bootstrap,
-        user_agent::{UserAgentConnection, UserAgentCredentials, auth},
-    },
+    actors::{GlobalActors, bootstrap::GetToken, vault::Bootstrap},
    crypto::integrity,
    db::{self, schema},
+    peers::user_agent::{self, Credentials, UserAgentConnection, auth, vault_gate},
 };
+
+use async_trait::async_trait;
 use diesel::{ExpressionMethods as _, QueryDsl, insert_into};
 use diesel_async::RunQueryDsl;
 use ml_dsa::{KeyGen, MlDsa87, SigningKey, signature::Keypair as _};
-
-use super::common::ChannelTransport;
+use tokio::sync::mpsc;

 fn sign_useragent_challenge(
    key: &SigningKey<MlDsa87>,
-    nonce: i32,
-    pubkey_bytes: &[u8],
+    challenge: &AuthChallenge,
 ) -> authn::Signature {
-    let challenge = format_challenge(nonce, pubkey_bytes);
+    let challenge = challenge.format();
    key.signing_key()
        .sign_deterministic(&challenge, USERAGENT_CONTEXT)
        .unwrap()
        .into()
 }

+fn tamper_challenge(challenge: &AuthChallenge) -> AuthChallenge {
+    let mut challenge = challenge.clone();
+    challenge.nonce[0] ^= 1;
+    challenge
+}
+
+struct NullOobSender;
+
+#[async_trait]
+impl Sender<user_agent::OutOfBand> for NullOobSender {
+    async fn send(&mut self, _item: user_agent::OutOfBand) -> Result<(), TransportError> {
+        Ok(())
+    }
+}
+
+struct StartServerTransport {
+    auth_rx: mpsc::Receiver<auth::Inbound>,
+    auth_tx: mpsc::Sender<Result<auth::Outbound, auth::Error>>,
+    vault_rx: mpsc::Receiver<vault_gate::Inbound>,
+    vault_tx: mpsc::Sender<Result<vault_gate::Outbound, vault_gate::Error>>,
+}
+
+struct StartTestTransport {
+    auth_rx: mpsc::Receiver<Result<auth::Outbound, auth::Error>>,
+    auth_tx: mpsc::Sender<auth::Inbound>,
+}
+
+fn start_transport_pair() -> (StartServerTransport, StartTestTransport) {
+    let (auth_in_tx, auth_in_rx) = mpsc::channel(10);
+    let (auth_out_tx, auth_out_rx) = mpsc::channel(10);
+    let (_vault_in_tx, vault_in_rx) = mpsc::channel(10);
+    let (vault_out_tx, _vault_out_rx) = mpsc::channel(10);
+
+    (
+        StartServerTransport {
+            auth_rx: auth_in_rx,
+            auth_tx: auth_out_tx,
+            vault_rx: vault_in_rx,
+            vault_tx: vault_out_tx,
+        },
+        StartTestTransport {
+            auth_rx: auth_out_rx,
+            auth_tx: auth_in_tx,
+        },
+    )
+}
+
+#[async_trait]
+impl Receiver<auth::Inbound> for StartServerTransport {
+    async fn recv(&mut self) -> Option<auth::Inbound> {
+        self.auth_rx.recv().await
+    }
+}
+
+#[async_trait]
+impl Sender<Result<auth::Outbound, auth::Error>> for StartServerTransport {
+    async fn send(
+        &mut self,
+        item: Result<auth::Outbound, auth::Error>,
+    ) -> Result<(), TransportError> {
+        self.auth_tx
+            .send(item)
+            .await
+            .map_err(|_| TransportError::ChannelClosed)
+    }
+}
+
+impl arbiter_proto::transport::Bi<auth::Inbound, Result<auth::Outbound, auth::Error>>
+    for StartServerTransport
+{
+}
+
+#[async_trait]
+impl Receiver<vault_gate::Inbound> for StartServerTransport {
+    async fn recv(&mut self) -> Option<vault_gate::Inbound> {
+        self.vault_rx.recv().await
+    }
+}
+
+#[async_trait]
+impl Sender<Result<vault_gate::Outbound, vault_gate::Error>> for StartServerTransport {
+    async fn send(
+        &mut self,
+        item: Result<vault_gate::Outbound, vault_gate::Error>,
+    ) -> Result<(), TransportError> {
+        self.vault_tx
+            .send(item)
+            .await
+            .map_err(|_| TransportError::ChannelClosed)
+    }
+}
+
+impl
+    arbiter_proto::transport::Bi<
+        vault_gate::Inbound,
+        Result<vault_gate::Outbound, vault_gate::Error>,
+    > for StartServerTransport
+{
+}
+
+#[async_trait]
+impl Receiver<Result<auth::Outbound, auth::Error>> for StartTestTransport {
+    async fn recv(&mut self) -> Option<Result<auth::Outbound, auth::Error>> {
+        self.auth_rx.recv().await
+    }
+}
+
+#[async_trait]
+impl Sender<auth::Inbound> for StartTestTransport {
+    async fn send(&mut self, item: auth::Inbound) -> Result<(), TransportError> {
+        self.auth_tx
+            .send(item)
+            .await
+            .map_err(|_| TransportError::ChannelClosed)
+    }
+}
+
 #[tokio::test]
 #[test_log::test]
-pub async fn test_bootstrap_token_auth() {
+async fn test_bootstrap_token_auth() {
    let db = db::create_test_pool().await;
    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
    actors
-        .key_holder
+        .vault
        .ask(Bootstrap {
            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
        })
@@ -46,11 +159,11 @@ pub async fn test_bootstrap_token_auth() {
        .unwrap();
    let token = actors.bootstrapper.ask(GetToken).await.unwrap().unwrap();

-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
    let db_for_task = db.clone();
    let task = tokio::spawn(async move {
        let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        auth::authenticate(&mut props, &mut server_transport).await
    });

    let new_key = MlDsa87::key_gen(&mut rand::rng());
@@ -62,14 +175,29 @@ pub async fn test_bootstrap_token_auth() {
        .await
        .unwrap();

+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive challenge");
+    let challenge = match response {
+        Ok(auth::Outbound::AuthChallenge { challenge }) => challenge,
+        other => panic!("Expected AuthChallenge, got {other:?}"),
+    };
+
+    let signature = sign_useragent_challenge(&new_key, &challenge);
+
+    test_transport
+        .send(auth::Inbound::AuthChallengeSolution {
+            signature: signature.to_bytes(),
+        })
+        .await
+        .unwrap();
+
    let response = test_transport
        .recv()
        .await
        .expect("should receive auth result");
-    match response {
-        Ok(auth::Outbound::AuthSuccess) => {}
-        other => panic!("Expected AuthSuccess, got {other:?}"),
-    }
+    assert!(matches!(response, Ok(auth::Outbound::AuthSuccess)));

    task.await.unwrap().unwrap();

@@ -84,15 +212,15 @@ pub async fn test_bootstrap_token_auth() {

 #[tokio::test]
 #[test_log::test]
-pub async fn test_bootstrap_invalid_token_auth() {
+async fn test_bootstrap_invalid_token_auth() {
    let db = db::create_test_pool().await;
    let actors = GlobalActors::spawn(db.clone()).await.unwrap();

-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
    let db_for_task = db.clone();
    let task = tokio::spawn(async move {
        let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        auth::authenticate(&mut props, &mut server_transport).await
    });

    let new_key = MlDsa87::key_gen(&mut rand::rng());
@@ -104,6 +232,23 @@ pub async fn test_bootstrap_invalid_token_auth() {
        .await
        .unwrap();

+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive challenge");
+    let challenge = match response {
+        Ok(auth::Outbound::AuthChallenge { challenge }) => challenge,
+        other => panic!("Expected AuthChallenge, got {other:?}"),
+    };
+
+    let signature = sign_useragent_challenge(&new_key, &challenge);
+    test_transport
+        .send(auth::Inbound::AuthChallengeSolution {
+            signature: signature.to_bytes(),
+        })
+        .await
+        .unwrap();
+
    assert!(matches!(
        task.await.unwrap(),
        Err(auth::Error::InvalidBootstrapToken)
@@ -120,11 +265,11 @@ pub async fn test_bootstrap_invalid_token_auth() {

 #[tokio::test]
 #[test_log::test]
-pub async fn test_challenge_auth() {
+async fn test_challenge_auth() {
    let db = db::create_test_pool().await;
    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
    actors
-        .key_holder
+        .vault
        .ask(Bootstrap {
            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
        })
@@ -137,20 +282,17 @@ pub async fn test_challenge_auth() {
    {
        let mut conn = db.get().await.unwrap();
        let id: i32 = insert_into(schema::useragent_client::table)
-            .values((
-                schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
-                schema::useragent_client::key_type.eq(1i32),
-            ))
+            .values((schema::useragent_client::public_key.eq(pubkey_bytes.clone()),))
            .returning(schema::useragent_client::id)
            .get_result(&mut conn)
            .await
            .unwrap();
        integrity::sign_entity(
            &mut conn,
-            &actors.key_holder,
-            &UserAgentCredentials {
+            &actors.vault,
+            &Credentials {
+                id,
                pubkey: new_key.verifying_key().into(),
-                nonce: 1,
            },
            id,
        )
@@ -158,11 +300,11 @@ pub async fn test_challenge_auth() {
        .unwrap();
    }

-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
    let db_for_task = db.clone();
    let task = tokio::spawn(async move {
        let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        auth::authenticate(&mut props, &mut server_transport).await
    });

    test_transport
@@ -179,13 +321,13 @@ pub async fn test_challenge_auth() {
        .expect("should receive challenge");
    let challenge = match response {
        Ok(resp) => match resp {
-            auth::Outbound::AuthChallenge { nonce } => nonce,
+            auth::Outbound::AuthChallenge { challenge } => challenge,
            other => panic!("Expected AuthChallenge, got {other:?}"),
        },
        Err(err) => panic!("Expected Ok response, got Err({err:?})"),
    };

-    let signature = sign_useragent_challenge(&new_key, challenge, &pubkey_bytes);
+    let signature = sign_useragent_challenge(&new_key, &challenge);

    test_transport
        .send(auth::Inbound::AuthChallengeSolution {
@@ -208,12 +350,12 @@ pub async fn test_challenge_auth() {

 #[tokio::test]
 #[test_log::test]
-pub async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed() {
+async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed() {
    let db = db::create_test_pool().await;
    let actors = GlobalActors::spawn(db.clone()).await.unwrap();

    actors
-        .key_holder
+        .vault
        .ask(Bootstrap {
            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
        })
@@ -226,81 +368,17 @@ pub async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed()
    {
        let mut conn = db.get().await.unwrap();
        insert_into(schema::useragent_client::table)
-            .values((
-                schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
-                schema::useragent_client::key_type.eq(1i32),
-            ))
+            .values((schema::useragent_client::public_key.eq(pubkey_bytes.clone()),))
            .execute(&mut conn)
            .await
            .unwrap();
    }

-    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let (server_transport, mut test_transport) = start_transport_pair();
    let db_for_task = db.clone();
    let task = tokio::spawn(async move {
        let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
-    });
-
-    test_transport
-        .send(auth::Inbound::AuthChallengeRequest {
-            pubkey: new_key.verifying_key().into(),
-            bootstrap_token: None,
-        })
-        .await
-        .unwrap();
-
-    assert!(matches!(
-        task.await.unwrap(),
-        Err(auth::Error::Internal { .. })
-    ));
-}
-
-#[tokio::test]
-#[test_log::test]
-pub async fn test_challenge_auth_rejects_invalid_signature() {
-    let db = db::create_test_pool().await;
-    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
-    actors
-        .key_holder
-        .ask(Bootstrap {
-            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
-        })
-        .await
-        .unwrap();
-
-    let new_key = MlDsa87::key_gen(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().encode().to_vec();
-
-    {
-        let mut conn = db.get().await.unwrap();
-        let id: i32 = insert_into(schema::useragent_client::table)
-            .values((
-                schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
-                schema::useragent_client::key_type.eq(1i32),
-            ))
-            .returning(schema::useragent_client::id)
-            .get_result(&mut conn)
-            .await
-            .unwrap();
-        integrity::sign_entity(
-            &mut conn,
-            &actors.key_holder,
-            &UserAgentCredentials {
-                pubkey: new_key.verifying_key().into(),
-                nonce: 1,
-            },
-            id,
-        )
-        .await
-        .unwrap();
-    }
-
-    let (server_transport, mut test_transport) = ChannelTransport::new();
-    let db_for_task = db.clone();
-    let task = tokio::spawn(async move {
-        let mut props = UserAgentConnection::new(db_for_task, actors);
-        auth::authenticate(&mut props, server_transport).await
+        user_agent::start(&mut props, server_transport, Box::new(NullOobSender)).await
    });

    test_transport
@@ -317,13 +395,98 @@ pub async fn test_challenge_auth_rejects_invalid_signature() {
        .expect("should receive challenge");
    let challenge = match response {
        Ok(resp) => match resp {
-            auth::Outbound::AuthChallenge { nonce } => nonce,
+            auth::Outbound::AuthChallenge { challenge } => challenge,
            other => panic!("Expected AuthChallenge, got {other:?}"),
        },
        Err(err) => panic!("Expected Ok response, got Err({err:?})"),
    };

-    let signature = sign_useragent_challenge(&new_key, challenge + 1, &pubkey_bytes);
+    let signature = sign_useragent_challenge(&new_key, &challenge);
+
+    test_transport
+        .send(auth::Inbound::AuthChallengeSolution {
+            signature: signature.to_bytes(),
+        })
+        .await
+        .unwrap();
+
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive auth result");
+    assert!(matches!(response, Ok(auth::Outbound::AuthSuccess)));
+
+    assert!(matches!(
+        task.await.unwrap(),
+        Err(user_agent::Error::Internal(_))
+    ));
+}
+
+#[tokio::test]
+#[test_log::test]
+async fn test_challenge_auth_rejects_invalid_signature() {
+    let db = db::create_test_pool().await;
+    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+    actors
+        .vault
+        .ask(Bootstrap {
+            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
+        })
+        .await
+        .unwrap();
+
+    let new_key = MlDsa87::key_gen(&mut rand::rng());
+    let pubkey_bytes = new_key.verifying_key().encode().to_vec();
+
+    {
+        let mut conn = db.get().await.unwrap();
+        let id: i32 = insert_into(schema::useragent_client::table)
+            .values((schema::useragent_client::public_key.eq(pubkey_bytes.clone()),))
+            .returning(schema::useragent_client::id)
+            .get_result(&mut conn)
+            .await
+            .unwrap();
+        integrity::sign_entity(
+            &mut conn,
+            &actors.vault,
+            &Credentials {
+                id,
+                pubkey: new_key.verifying_key().into(),
+            },
+            id,
+        )
+        .await
+        .unwrap();
+    }
+
+    let (mut server_transport, mut test_transport) = ChannelTransport::new();
+    let db_for_task = db.clone();
+    let task = tokio::spawn(async move {
+        let mut props = UserAgentConnection::new(db_for_task, actors);
+        auth::authenticate(&mut props, &mut server_transport).await
+    });
+
+    test_transport
+        .send(auth::Inbound::AuthChallengeRequest {
+            pubkey: new_key.verifying_key().into(),
+            bootstrap_token: None,
+        })
+        .await
+        .unwrap();
+
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive challenge");
+    let challenge = match response {
+        Ok(resp) => match resp {
+            auth::Outbound::AuthChallenge { challenge } => challenge,
+            other => panic!("Expected AuthChallenge, got {other:?}"),
+        },
+        Err(err) => panic!("Expected Ok response, got Err({err:?})"),
+    };
+
+    let signature = sign_useragent_challenge(&new_key, &tamper_challenge(&challenge));

    test_transport
        .send(auth::Inbound::AuthChallengeSolution {
--- a/server/crates/arbiter-server/tests/user_agent/unseal.rs
+++ b/server/crates/arbiter-server/tests/user_agent/unseal.rs
@@ -1,49 +1,62 @@
-use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
+use arbiter_crypto::{
+    authn,
+    safecell::{SafeCell, SafeCellHandle as _},
+};
 use arbiter_server::{
    actors::{
        GlobalActors,
-        keyholder::{Bootstrap, Seal},
-        user_agent::{
-            UserAgentSession,
-            session::connection::{HandleUnsealEncryptedKey, HandleUnsealRequest, UnsealError},
-        },
+        vault::{Bootstrap, Seal},
    },
    db,
+    peers::user_agent::{
+        Credentials,
+        vault_gate::{
+            Error as VaultGateError, HandleHandshake, HandleUnsealEncryptedKey, VaultGate,
+        },
+    },
 };

 use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
 use kameo::actor::Spawn as _;
+use tokio::sync::oneshot;
 use x25519_dalek::{EphemeralSecret, PublicKey};

-async fn setup_sealed_user_agent(
+async fn setup_sealed_gate(
    seal_key: &[u8],
-) -> (db::DatabasePool, kameo::actor::ActorRef<UserAgentSession>) {
+) -> (
+    db::DatabasePool,
+    kameo::actor::ActorRef<VaultGate>,
+    oneshot::Receiver<Result<(), VaultGateError>>,
+) {
    let db = db::create_test_pool().await;
    let actors = GlobalActors::spawn(db.clone()).await.unwrap();

    actors
-        .key_holder
+        .vault
        .ask(Bootstrap {
            seal_key_raw: SafeCell::new(seal_key.to_vec()),
        })
        .await
        .unwrap();
-    actors.key_holder.ask(Seal).await.unwrap();
+    actors.vault.ask(Seal).await.unwrap();

-    let session = UserAgentSession::spawn(UserAgentSession::new_test(db.clone(), actors));
+    let (promotion_tx, promotion_rx) = oneshot::channel();
+    let pubkey = authn::SigningKey::generate().public_key();
+    let auth_creds = Credentials { id: 1, pubkey };
+    let gate = VaultGate::spawn(VaultGate::new(auth_creds, actors, db.clone(), promotion_tx));

-    (db, session)
+    (db, gate, promotion_rx)
 }

 async fn client_dh_encrypt(
-    user_agent: &kameo::actor::ActorRef<UserAgentSession>,
+    gate: &kameo::actor::ActorRef<VaultGate>,
    key_to_send: &[u8],
 ) -> HandleUnsealEncryptedKey {
    let client_secret = EphemeralSecret::random();
    let client_public = PublicKey::from(&client_secret);

-    let response = user_agent
-        .ask(HandleUnsealRequest {
+    let response = gate
+        .ask(HandleHandshake {
            client_pubkey: client_public,
        })
        .await
@@ -69,48 +82,47 @@ async fn client_dh_encrypt(

 #[tokio::test]
 #[test_log::test]
-pub async fn test_unseal_success() {
+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;
+async fn test_unseal_wrong_seal_key() {
+    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
        ))
    ));
 }

 #[tokio::test]
 #[test_log::test]
-pub async fn test_unseal_corrupted_ciphertext() {
-    let (_db, user_agent) = setup_sealed_user_agent(b"test-key").await;
+async fn test_unseal_corrupted_ciphertext() {
+    let (_db, gate, _promotion_rx) = setup_sealed_gate(b"test-key").await;

    let client_secret = EphemeralSecret::random();
    let client_public = PublicKey::from(&client_secret);

-    user_agent
-        .ask(HandleUnsealRequest {
-            client_pubkey: client_public,
-        })
-        .await
-        .unwrap();
+    gate.ask(HandleHandshake {
+        client_pubkey: client_public,
+    })
+    .await
+    .unwrap();

-    let response = user_agent
+    let response = gate
        .ask(HandleUnsealEncryptedKey {
            nonce: vec![0u8; 24],
            ciphertext: vec![0u8; 32],
@@ -121,33 +133,33 @@ pub async fn test_unseal_corrupted_ciphertext() {
    assert!(matches!(
        response,
        Err(kameo::error::SendError::HandlerError(
-            UnsealError::InvalidKey
+            VaultGateError::InvalidKey
        ))
    ));
 }

 #[tokio::test]
 #[test_log::test]
-pub async fn test_unseal_retry_after_invalid_key() {
+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(())));
    }
 }
--- a/server/crates/arbiter-server/tests/vault.rs
+++ b/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;
--- a/server/crates/arbiter-server/tests/keyholder/concurrency.rs
+++ b/server/crates/arbiter-server/tests/keyholder/concurrency.rs
@@ -1,20 +1,21 @@
-use std::collections::{HashMap, HashSet};
-
+use crate::common;
 use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_server::{
-    actors::keyholder::{CreateNew, Error, KeyHolder},
+    actors::{
+        GlobalActors,
+        vault::{CreateNew, Error, Vault},
+    },
    db::{self, models, schema},
 };

 use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper, dsl::sql_query};
 use diesel_async::RunQueryDsl;
 use kameo::actor::{ActorRef, Spawn as _};
+use std::collections::{HashMap, HashSet};
 use tokio::task::JoinSet;

-use crate::common;
-
 async fn write_concurrently(
-    actor: ActorRef<KeyHolder>,
+    actor: ActorRef<Vault>,
    prefix: &'static str,
    count: usize,
 ) -> Vec<(i32, Vec<u8>)> {
@@ -44,7 +45,7 @@ async fn write_concurrently(
 #[test_log::test]
 async fn concurrent_create_new_no_duplicate_nonces_() {
    let db = db::create_test_pool().await;
-    let actor = KeyHolder::spawn(common::bootstrapped_keyholder(&db).await);
+    let actor = Vault::spawn(common::bootstrapped_vault(&db).await);

    let writes = write_concurrently(actor, "nonce-unique", 32).await;
    assert_eq!(writes.len(), 32);
@@ -66,7 +67,7 @@ async fn concurrent_create_new_no_duplicate_nonces_() {
 #[test_log::test]
 async fn concurrent_create_new_root_nonce_never_moves_backward() {
    let db = db::create_test_pool().await;
-    let actor = KeyHolder::spawn(common::bootstrapped_keyholder(&db).await);
+    let actor = Vault::spawn(common::bootstrapped_vault(&db).await);

    write_concurrently(actor, "root-max", 24).await;

@@ -94,7 +95,7 @@ async fn concurrent_create_new_root_nonce_never_moves_backward() {
 #[test_log::test]
 async fn insert_failure_does_not_create_partial_row() {
    let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
    let root_key_history_id = common::root_key_history_id(&db).await;

    let mut conn = db.get().await.unwrap();
@@ -156,12 +157,14 @@ async fn insert_failure_does_not_create_partial_row() {
 #[test_log::test]
 async fn decrypt_roundtrip_after_high_concurrency() {
    let db = db::create_test_pool().await;
-    let actor = KeyHolder::spawn(common::bootstrapped_keyholder(&db).await);
+    let actor = Vault::spawn(common::bootstrapped_vault(&db).await);

    let writes = write_concurrently(actor, "roundtrip", 40).await;
    let expected: HashMap<i32, Vec<u8>> = writes.into_iter().collect();

-    let mut decryptor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut decryptor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
    decryptor
        .try_unseal(SafeCell::new(b"test-seal-key".to_vec()))
        .await
--- a/server/crates/arbiter-server/tests/keyholder/lifecycle.rs
+++ b/server/crates/arbiter-server/tests/keyholder/lifecycle.rs
@@ -1,6 +1,10 @@
+use crate::common;
 use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_server::{
-    actors::keyholder::{Error, KeyHolder},
+    actors::{
+        GlobalActors,
+        vault::{Error, Vault},
+    },
    crypto::encryption::v1::{Nonce, ROOT_KEY_TAG},
    db::{self, models, schema},
 };
@@ -8,13 +12,13 @@ use arbiter_server::{
 use diesel::{QueryDsl, SelectableHelper};
 use diesel_async::RunQueryDsl;

-use crate::common;
-
 #[tokio::test]
 #[test_log::test]
 async fn test_bootstrap() {
    let db = db::create_test_pool().await;
-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();

    let seal_key = SafeCell::new(b"test-seal-key".to_vec());
    actor.bootstrap(seal_key).await.unwrap();
@@ -37,7 +41,7 @@ async fn test_bootstrap() {
 #[test_log::test]
 async fn test_bootstrap_rejects_double() {
    let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;

    let seal_key2 = SafeCell::new(b"test-seal-key".to_vec());
    let err = actor.bootstrap(seal_key2).await.unwrap_err();
@@ -48,7 +52,9 @@ async fn test_bootstrap_rejects_double() {
 #[test_log::test]
 async fn test_create_new_before_bootstrap_fails() {
    let db = db::create_test_pool().await;
-    let mut actor = KeyHolder::new(db).await.unwrap();
+    let mut actor = Vault::new(db, GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();

    let err = actor
        .create_new(SafeCell::new(b"data".to_vec()))
@@ -61,7 +67,9 @@ async fn test_create_new_before_bootstrap_fails() {
 #[test_log::test]
 async fn test_decrypt_before_bootstrap_fails() {
    let db = db::create_test_pool().await;
-    let mut actor = KeyHolder::new(db).await.unwrap();
+    let mut actor = Vault::new(db, GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();

    let err = actor.decrypt(1).await.unwrap_err();
    assert!(matches!(err, Error::NotBootstrapped));
@@ -71,19 +79,21 @@ async fn test_decrypt_before_bootstrap_fails() {
 #[test_log::test]
 async fn test_new_restores_sealed_state() {
    let db = db::create_test_pool().await;
-    let actor = common::bootstrapped_keyholder(&db).await;
+    let actor = common::bootstrapped_vault(&db).await;
    drop(actor);

-    let mut actor2 = KeyHolder::new(db).await.unwrap();
+    let mut actor2 = Vault::new(db, GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
    let err = actor2.decrypt(1).await.unwrap_err();
-    assert!(matches!(err, Error::NotBootstrapped));
+    assert!(matches!(err, Error::Sealed));
 }

 #[tokio::test]
 #[test_log::test]
 async fn test_unseal_correct_password() {
    let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;

    let plaintext = b"survive a restart";
    let aead_id = actor
@@ -92,7 +102,9 @@ async fn test_unseal_correct_password() {
        .unwrap();
    drop(actor);

-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();
    let seal_key = SafeCell::new(b"test-seal-key".to_vec());
    actor.try_unseal(seal_key).await.unwrap();

@@ -104,7 +116,7 @@ async fn test_unseal_correct_password() {
 #[test_log::test]
 async fn test_unseal_wrong_then_correct_password() {
    let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;

    let plaintext = b"important data";
    let aead_id = actor
@@ -113,7 +125,9 @@ async fn test_unseal_wrong_then_correct_password() {
        .unwrap();
    drop(actor);

-    let mut actor = KeyHolder::new(db.clone()).await.unwrap();
+    let mut actor = Vault::new(db.clone(), GlobalActors::spawn_message_bus())
+        .await
+        .unwrap();

    let bad_key = SafeCell::new(b"wrong-password".to_vec());
    let err = actor.try_unseal(bad_key).await.unwrap_err();
--- a/server/crates/arbiter-server/tests/keyholder/storage.rs
+++ b/server/crates/arbiter-server/tests/keyholder/storage.rs
@@ -1,22 +1,20 @@
-use std::collections::HashSet;
-
+use crate::common;
 use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_server::{
-    actors::keyholder::Error,
+    actors::vault::Error,
    crypto::encryption::v1::Nonce,
    db::{self, models, schema},
 };

 use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper, dsl::update};
 use diesel_async::RunQueryDsl;
-
-use crate::common;
+use std::collections::HashSet;

 #[tokio::test]
 #[test_log::test]
 async fn test_create_decrypt_roundtrip() {
    let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;

    let plaintext = b"hello arbiter";
    let aead_id = actor
@@ -32,7 +30,7 @@ async fn test_create_decrypt_roundtrip() {
 #[test_log::test]
 async fn test_decrypt_nonexistent_returns_not_found() {
    let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;

    let err = actor.decrypt(9999).await.unwrap_err();
    assert!(matches!(err, Error::NotFound));
@@ -42,7 +40,7 @@ async fn test_decrypt_nonexistent_returns_not_found() {
 #[test_log::test]
 async fn test_ciphertext_differs_across_entries() {
    let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;

    let plaintext = b"same content";
    let id1 = actor
@@ -80,7 +78,7 @@ async fn test_ciphertext_differs_across_entries() {
 #[test_log::test]
 async fn test_nonce_never_reused() {
    let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;

    let n = 5;
    for i in 0..n {
@@ -124,7 +122,7 @@ async fn test_nonce_never_reused() {
 #[test_log::test]
 async fn broken_db_nonce_format_fails_closed() {
    let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
    let root_key_history_id = common::root_key_history_id(&db).await;

    let mut conn = db.get().await.unwrap();
@@ -145,7 +143,7 @@ async fn broken_db_nonce_format_fails_closed() {
    assert!(matches!(err, Error::BrokenDatabase));

    let db = db::create_test_pool().await;
-    let mut actor = common::bootstrapped_keyholder(&db).await;
+    let mut actor = common::bootstrapped_vault(&db).await;
    let id = actor
        .create_new(SafeCell::new(b"decrypt target".to_vec()))
        .await
--- a/useragent/flutter_rust_bridge.yaml
+++ b/useragent/flutter_rust_bridge.yaml
@@ -0,0 +1,3 @@
+rust_input: crate::api
+rust_root: rust/
+dart_output: lib/src/rust
--- a/useragent/lib/features/callouts/callout_event.dart
+++ b/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;
 }
--- a/useragent/lib/features/callouts/show_callout.dart
+++ b/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(
--- a/useragent/lib/features/callouts/show_callout_list.dart
+++ b/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,
+                  ),
                ),
              ),
            ),
--- a/Show More
+++ b/Show More