diff --git a/server/Cargo.lock b/server/Cargo.lock
index fc4628a..dcd37c5 100644
--- a/server/Cargo.lock
+++ b/server/Cargo.lock
@@ -744,6 +744,8 @@ dependencies = [
  "kameo",
  "memsafe",
  "pem",
+ "postcard",
+ "prost",
  "prost-types",
  "rand 0.10.0",
  "rcgen",
@@ -751,6 +753,8 @@ dependencies = [
  "rsa",
  "rustls",
  "secrecy",
+ "serde",
+ "serde_with",
  "sha2 0.10.9",
  "smlang",
  "spki",
@@ -1053,6 +1057,15 @@ dependencies = [
  "syn 2.0.117",
 ]
 
+[[package]]
+name = "atomic-polyfill"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8cf2bce30dfe09ef0bfaef228b9d414faaf7e563035494d7fe092dba54b300f4"
+dependencies = [
+ "critical-section",
+]
+
 [[package]]
 name = "atomic-waker"
 version = "1.1.2"
@@ -1443,6 +1456,15 @@ dependencies = [
  "cc",
 ]
 
+[[package]]
+name = "cobs"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fa961b519f0b462e3a3b4a34b64d119eeaca1d59af726fe450bbba07a9fc0a1"
+dependencies = [
+ "thiserror 2.0.18",
+]
+
 [[package]]
 name = "console"
 version = "0.15.11"
@@ -1550,6 +1572,12 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "critical-section"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "790eea4361631c5e7d22598ecd5723ff611904e3344ce8720784c93e3d83d40b"
+
 [[package]]
 name = "crossbeam-utils"
 version = "0.8.21"
@@ -1955,6 +1983,7 @@ version = "3.0.0-rc.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c6e914c7c52decb085cea910552e24c63ac019e3ab8bf001ff736da9a9d9d890"
 dependencies = [
+ "serde",
  "signature 3.0.0-rc.10",
 ]
 
@@ -1967,6 +1996,7 @@ dependencies = [
  "curve25519-dalek 5.0.0-pre.6",
  "ed25519",
  "rand_core 0.10.0",
+ "serde",
  "sha2 0.11.0-rc.5",
  "subtle",
  "zeroize",
@@ -2013,6 +2043,18 @@ dependencies = [
  "zeroize",
 ]
 
+[[package]]
+name = "embedded-io"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef1a6892d9eef45c8fa6b9e0086428a2cca8491aca8f787c534a3d6d0bcb3ced"
+
+[[package]]
+name = "embedded-io"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "edd0f118536f44f5ccd48bcb8b111bdc3de888b58c74639dfb034a357d0f206d"
+
 [[package]]
 name = "encode_unicode"
 version = "1.0.0"
@@ -2052,7 +2094,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
 dependencies = [
  "libc",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -2430,6 +2472,15 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "hash32"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b0c35f58762feb77d74ebe43bdbc3210f09be9fe6742234d573bacc26ed92b67"
+dependencies = [
+ "byteorder",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.12.3"
@@ -2464,6 +2515,20 @@ dependencies = [
  "serde_core",
 ]
 
+[[package]]
+name = "heapless"
+version = "0.7.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdc6457c0eb62c71aac4bc17216026d8410337c4126773b9c5daba343f17964f"
+dependencies = [
+ "atomic-polyfill",
+ "hash32",
+ "rustc_version 0.4.1",
+ "serde",
+ "spin",
+ "stable_deref_trait",
+]
+
 [[package]]
 name = "heck"
 version = "0.5.0"
@@ -3187,7 +3252,7 @@ version = "0.50.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7957b9740744892f114936ab4a57b3f487491bbeafaf8083688b16841a4240e5"
 dependencies = [
- "windows-sys 0.59.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -3212,6 +3277,7 @@ dependencies = [
  "num-iter",
  "num-traits",
  "rand 0.8.5",
+ "serde",
  "smallvec",
  "zeroize",
 ]
@@ -3523,6 +3589,19 @@ version = "1.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c33a9471896f1c69cecef8d20cbe2f7accd12527ce60845ff44c153bb2a21b49"
 
+[[package]]
+name = "postcard"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6764c3b5dd454e283a30e6dfe78e9b31096d9e32036b5d1eaac7a6119ccb9a24"
+dependencies = [
+ "cobs",
+ "embedded-io 0.4.0",
+ "embedded-io 0.6.1",
+ "heapless",
+ "serde",
+]
+
 [[package]]
 name = "potential_utf"
 version = "0.1.4"
@@ -4151,6 +4230,7 @@ dependencies = [
  "pkcs1",
  "pkcs8",
  "rand_core 0.6.4",
+ "serde",
  "sha2 0.10.9",
  "signature 2.2.0",
  "spki",
@@ -4286,7 +4366,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -4702,7 +4782,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3a766e1110788c36f4fa1c2b71b387a7815aa65f88ce0229841826633d93723e"
 dependencies = [
  "libc",
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -4710,6 +4790,9 @@ name = "spin"
 version = "0.9.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
+dependencies = [
+ "lock_api",
+]
 
 [[package]]
 name = "spki"
@@ -4896,7 +4979,7 @@ dependencies = [
  "getrandom 0.4.2",
  "once_cell",
  "rustix",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
diff --git a/server/Cargo.toml b/server/Cargo.toml
index 1e41511..52d0794 100644
--- a/server/Cargo.toml
+++ b/server/Cargo.toml
@@ -42,4 +42,5 @@ k256 = { version = "0.13.4", features = ["ecdsa", "pkcs8"] }
 rsa = { version = "0.9", features = ["sha2"] }
 sha2 = "0.10"
 spki = "0.7"
-miette = { version = "7.6.0", features = ["fancy", "serde"] }
\ No newline at end of file
+prost = "0.14.3"
+miette = { version = "7.6.0", features = ["fancy", "serde"] }
diff --git a/server/crates/arbiter-proto/Cargo.toml b/server/crates/arbiter-proto/Cargo.toml
index 8299691..e1651a7 100644
--- a/server/crates/arbiter-proto/Cargo.toml
+++ b/server/crates/arbiter-proto/Cargo.toml
@@ -11,7 +11,7 @@ tokio.workspace = true
 futures.workspace = true
 hex = "0.4.3"
 tonic-prost = "0.14.5"
-prost = "0.14.3"
+prost.workspace = true
 kameo.workspace = true
 url = "2.5.8"
 miette.workspace = true
diff --git a/server/crates/arbiter-server/Cargo.toml b/server/crates/arbiter-server/Cargo.toml
index ccff5ba..a0bdae2 100644
--- a/server/crates/arbiter-server/Cargo.toml
+++ b/server/crates/arbiter-server/Cargo.toml
@@ -17,6 +17,7 @@ diesel-async = { version = "0.8.0", features = [
     "tokio",
 ] }
 ed25519-dalek.workspace = true
+ed25519-dalek.features = ["serde"]
 arbiter-proto.path = "../arbiter-proto"
 tracing.workspace = true
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
@@ -46,14 +47,20 @@ restructed = "0.2.2"
 strum = { version = "0.28.0", features = ["derive"] }
 pem = "3.0.6"
 k256.workspace = true
+k256.features = ["serde"]
 rsa.workspace = true
+rsa.features = ["serde"]
 sha2.workspace = true
 hmac = "0.12"
 spki.workspace = true
 alloy.workspace = true
 prost-types.workspace = true
+prost.workspace = true
 arbiter-tokens-registry.path = "../arbiter-tokens-registry"
 anyhow = "1.0.102"
+postcard = { version = "1.1.3", features = ["use-std"] }
+serde = { version = "1.0.228", features = ["derive"] }
+serde_with = "3.18.0"
 
 [dev-dependencies]
 insta = "1.46.3"
diff --git 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
index a34aa5a..7ec6729 100644
--- 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
@@ -47,7 +47,6 @@ create table if not exists useragent_client (
     id integer not null primary key,
     nonce integer not null default(1), -- used for auth challenge
     public_key blob not null,
-    pubkey_integrity_tag blob,
     key_type integer not null default(1), -- 1=Ed25519, 2=ECDSA(secp256k1)
     created_at integer not null default(unixepoch ('now')),
     updated_at integer not null default(unixepoch ('now'))
@@ -192,3 +191,19 @@ create table if not exists evm_ether_transfer_grant_target (
 ) STRICT;
 
 create unique index if not exists uniq_ether_transfer_target on evm_ether_transfer_grant_target (grant_id, address);
+
+-- ===============================
+-- Integrity Envelopes
+-- ===============================
+create table if not exists integrity_envelope (
+    id integer not null primary key,
+    entity_kind text not null,
+    entity_id blob not null,
+    payload_version integer not null,
+    key_version integer not null,
+    mac blob not null, -- 20-byte recipient address
+    signed_at integer not null default(unixepoch ('now')),
+    created_at integer not null default(unixepoch ('now'))
+) STRICT;
+
+create unique index if not exists uniq_integrity_envelope_entity on integrity_envelope (entity_kind, entity_id);
diff --git a/server/crates/arbiter-server/src/actors/evm/mod.rs b/server/crates/arbiter-server/src/actors/evm/mod.rs
index 5a3a2f7..a615e19 100644
--- a/server/crates/arbiter-server/src/actors/evm/mod.rs
+++ b/server/crates/arbiter-server/src/actors/evm/mod.rs
@@ -7,18 +7,18 @@ use kameo::{Actor, actor::ActorRef, messages};
 use rand::{SeedableRng, rng, rngs::StdRng};
 
 use crate::{
-    actors::keyholder::{CreateNew, Decrypt, KeyHolder},
+    actors::keyholder::{CreateNew, Decrypt, GetState, KeyHolder, KeyHolderState},
+    crypto::integrity,
     db::{
         DatabaseError, DatabasePool,
         models::{self, SqliteTimestamp},
         schema,
     },
     evm::{
-        self, RunKind,
-        policies::{
-            FullGrant, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
+        self, ListError, RunKind, policies::{
+            CombinedSettings, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
             ether_transfer::EtherTransfer, token_transfers::TokenTransfer,
-        },
+        }
     },
     safe_cell::{SafeCell, SafeCellHandle as _},
 };
@@ -56,6 +56,9 @@ pub enum Error {
 
     #[error("Database error: {0}")]
     Database(#[from] DatabaseError),
+
+    #[error("Integrity violation: {0}")]
+    Integrity(#[from] integrity::Error),
 }
 
 #[derive(Actor)]
@@ -71,7 +74,7 @@ impl EvmActor {
         // is it safe to seed rng from system once?
         // todo: audit
         let rng = StdRng::from_rng(&mut rng());
-        let engine = evm::Engine::new(db.clone());
+        let engine = evm::Engine::new(db.clone(), keyholder.clone());
         Self {
             keyholder,
             db,
@@ -132,46 +135,59 @@ impl EvmActor {
         &mut self,
         basic: SharedGrantSettings,
         grant: SpecificGrant,
-    ) -> Result<i32, DatabaseError> {
+    ) -> Result<i32, Error> {
         match grant {
-            SpecificGrant::EtherTransfer(settings) => {
-                self.engine
-                    .create_grant::<EtherTransfer>(FullGrant {
-                        basic,
-                        specific: settings,
-                    })
-                    .await
-            }
-            SpecificGrant::TokenTransfer(settings) => {
-                self.engine
-                    .create_grant::<TokenTransfer>(FullGrant {
-                        basic,
-                        specific: settings,
-                    })
-                    .await
-            }
+            SpecificGrant::EtherTransfer(settings) => self
+                .engine
+                .create_grant::<EtherTransfer>(CombinedSettings {
+                    shared: basic,
+                    specific: settings,
+                })
+                .await
+                .map_err(Error::from),
+            SpecificGrant::TokenTransfer(settings) => self
+                .engine
+                .create_grant::<TokenTransfer>(CombinedSettings {
+                    shared: basic,
+                    specific: settings,
+                })
+                .await
+                .map_err(Error::from),
         }
     }
 
     #[message]
     pub async fn useragent_delete_grant(&mut self, grant_id: i32) -> Result<(), Error> {
-        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
-        diesel::update(schema::evm_basic_grant::table)
-            .filter(schema::evm_basic_grant::id.eq(grant_id))
-            .set(schema::evm_basic_grant::revoked_at.eq(SqliteTimestamp::now()))
-            .execute(&mut conn)
-            .await
-            .map_err(DatabaseError::from)?;
-        Ok(())
+        // let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
+        // let keyholder = self.keyholder.clone();
+
+        // diesel_async::AsyncConnection::transaction(&mut conn, |conn| {
+        //     Box::pin(async move {
+        //         diesel::update(schema::evm_basic_grant::table)
+        //             .filter(schema::evm_basic_grant::id.eq(grant_id))
+        //             .set(schema::evm_basic_grant::revoked_at.eq(SqliteTimestamp::now()))
+        //             .execute(conn)
+        //             .await?;
+
+        //         let signed = integrity::evm::load_signed_grant_by_basic_id(conn, grant_id).await?;
+
+        //         diesel::result::QueryResult::Ok(())
+        //     })
+        // })
+        // .await
+        // .map_err(DatabaseError::from)?;
+
+        // Ok(())
+        todo!()
     }
 
     #[message]
     pub async fn useragent_list_grants(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
-        Ok(self
-            .engine
-            .list_all_grants()
-            .await
-            .map_err(DatabaseError::from)?)
+        match self.engine.list_all_grants().await {
+            Ok(grants) => Ok(grants),
+            Err(ListError::Database(db_err)) => Err(Error::Database(db_err)),
+            Err(ListError::Integrity(integrity_err)) => Err(Error::Integrity(integrity_err)),
+        }
     }
 
     #[message]
diff --git a/server/crates/arbiter-server/src/actors/keyholder/mod.rs b/server/crates/arbiter-server/src/actors/keyholder/mod.rs
index 0ef0d82..8e43129 100644
--- a/server/crates/arbiter-server/src/actors/keyholder/mod.rs
+++ b/server/crates/arbiter-server/src/actors/keyholder/mod.rs
@@ -4,6 +4,7 @@ use diesel::{
     dsl::{insert_into, update},
 };
 use diesel_async::{AsyncConnection, RunQueryDsl};
+use hmac::Mac as _;
 use kameo::{Actor, Reply, messages};
 use strum::{EnumDiscriminants, IntoDiscriminant};
 use tracing::{error, info};
@@ -12,7 +13,7 @@ use crate::{
     crypto::{
         KeyCell, derive_key,
         encryption::v1::{self, Nonce},
-        integrity::v1::compute_integrity_tag,
+        integrity::v1::HmacSha256,
     },
     safe_cell::SafeCell,
 };
@@ -250,22 +251,6 @@ impl KeyHolder {
         Ok(())
     }
 
-    // Signs a generic integrity payload using the vault-derived integrity key
-    #[message]
-    pub fn sign_integrity_tag(
-        &mut self,
-        purpose_tag: Vec<u8>,
-        data_parts: Vec<Vec<u8>>,
-    ) -> Result<Vec<u8>, Error> {
-        let State::Unsealed { root_key, .. } = &mut self.state else {
-            return Err(Error::NotBootstrapped);
-        };
-
-        let tag =
-            compute_integrity_tag(root_key, &purpose_tag, data_parts.iter().map(Vec::as_slice));
-        Ok(tag.to_vec())
-    }
-
     #[message]
     pub async fn decrypt(&mut self, aead_id: i32) -> Result<SafeCell<Vec<u8>>, Error> {
         let State::Unsealed { root_key, .. } = &mut self.state else {
@@ -339,6 +324,60 @@ impl KeyHolder {
         self.state.discriminant()
     }
 
+    #[message]
+    pub fn sign_integrity(&mut self, mac_input: Vec<u8>) -> Result<(i32, Vec<u8>), Error> {
+        let State::Unsealed {
+            root_key,
+            root_key_history_id,
+        } = &mut self.state
+        else {
+            return Err(Error::NotBootstrapped);
+        };
+
+        let mut hmac = root_key
+            .0
+            .read_inline(|k| match HmacSha256::new_from_slice(k) {
+                Ok(v) => v,
+                Err(_) => unreachable!("HMAC accepts keys of any size"),
+            });
+        hmac.update(&root_key_history_id.to_be_bytes());
+        hmac.update(&mac_input);
+
+        let mac = hmac.finalize().into_bytes().to_vec();
+        Ok((*root_key_history_id, mac))
+    }
+
+    #[message]
+    pub fn verify_integrity(
+        &mut self,
+        mac_input: Vec<u8>,
+        expected_mac: Vec<u8>,
+        key_version: i32,
+    ) -> Result<bool, Error> {
+        let State::Unsealed {
+            root_key,
+            root_key_history_id,
+        } = &mut self.state
+        else {
+            return Err(Error::NotBootstrapped);
+        };
+
+        if *root_key_history_id != key_version {
+            return Ok(false);
+        }
+
+        let mut hmac = root_key
+            .0
+            .read_inline(|k| match HmacSha256::new_from_slice(k) {
+                Ok(v) => v,
+                Err(_) => unreachable!("HMAC accepts keys of any size"),
+            });
+        hmac.update(&key_version.to_be_bytes());
+        hmac.update(&mac_input);
+
+        Ok(hmac.verify_slice(&expected_mac).is_ok())
+    }
+
     #[message]
     pub fn seal(&mut self) -> Result<(), Error> {
         let State::Unsealed {
diff --git a/server/crates/arbiter-server/src/actors/user_agent/auth.rs b/server/crates/arbiter-server/src/actors/user_agent/auth.rs
index 7e2cf9c..83b0472 100644
--- a/server/crates/arbiter-server/src/actors/user_agent/auth.rs
+++ b/server/crates/arbiter-server/src/actors/user_agent/auth.rs
@@ -37,6 +37,13 @@ impl Error {
     }
 }
 
+impl From<diesel::result::Error> for Error {
+    fn from(e: diesel::result::Error) -> Self {
+        error!(?e, "Database error");
+        Self::internal("Database error")
+    }
+}
+
 #[derive(Debug, Clone)]
 pub enum Outbound {
     AuthChallenge { nonce: i32 },
diff --git a/server/crates/arbiter-server/src/actors/user_agent/auth/state.rs b/server/crates/arbiter-server/src/actors/user_agent/auth/state.rs
index a9e0070..5ce6374 100644
--- a/server/crates/arbiter-server/src/actors/user_agent/auth/state.rs
+++ b/server/crates/arbiter-server/src/actors/user_agent/auth/state.rs
@@ -1,27 +1,20 @@
 use arbiter_proto::transport::Bi;
 use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl, update};
-use diesel_async::RunQueryDsl;
-use kameo::error::SendError;
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use kameo::{actor::ActorRef, error::SendError};
 use tracing::error;
 
 use super::Error;
 use crate::{
     actors::{
         bootstrap::ConsumeToken,
-        keyholder::{self, SignIntegrityTag},
-        user_agent::{AuthPublicKey, UserAgentConnection, auth::Outbound},
+        keyholder::KeyHolder,
+        user_agent::{AuthPublicKey, UserAgentConnection, UserAgentCredentials, auth::Outbound},
     },
-    crypto::integrity::v1::USERAGENT_INTEGRITY_TAG,
-    db::schema,
+    crypto::integrity::{self, AttestationStatus},
+    db::{DatabasePool, schema::useragent_client},
 };
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum AttestationStatus {
-    Attested,
-    NotAttested,
-    Unavailable,
-}
-
 pub struct ChallengeRequest {
     pub pubkey: AuthPublicKey,
 }
@@ -50,11 +43,11 @@ smlang::statemachine!(
     }
 );
 
-async fn create_nonce(
-    db: &crate::db::DatabasePool,
-    pubkey_bytes: &[u8],
-    key_type: crate::db::models::KeyType,
-) -> Result<i32, Error> {
+/// Returns the current nonce, ready to use for the challenge nonce.
+async fn get_current_nonce_and_id(
+    db: &DatabasePool,
+    key: &AuthPublicKey,
+) -> Result<(i32, i32), Error> {
     let mut db_conn = db.get().await.map_err(|e| {
         error!(error = ?e, "Database pool error");
         Error::internal("Database unavailable")
@@ -62,21 +55,12 @@ async fn create_nonce(
     db_conn
         .exclusive_transaction(|conn| {
             Box::pin(async move {
-                let current_nonce = schema::useragent_client::table
-                    .filter(schema::useragent_client::public_key.eq(pubkey_bytes.to_vec()))
-                    .filter(schema::useragent_client::key_type.eq(key_type))
-                    .select(schema::useragent_client::nonce)
-                    .first::<i32>(conn)
-                    .await?;
-
-                update(schema::useragent_client::table)
-                    .filter(schema::useragent_client::public_key.eq(pubkey_bytes.to_vec()))
-                    .filter(schema::useragent_client::key_type.eq(key_type))
-                    .set(schema::useragent_client::nonce.eq(current_nonce + 1))
-                    .execute(conn)
-                    .await?;
-
-                Result::<_, diesel::result::Error>::Ok(current_nonce)
+                useragent_client::table
+                    .filter(useragent_client::public_key.eq(key.to_stored_bytes()))
+                    .filter(useragent_client::key_type.eq(key.key_type()))
+                    .select((useragent_client::id, useragent_client::nonce))
+                    .first::<(i32, i32)>(conn)
+                    .await
             })
         })
         .await
@@ -86,15 +70,92 @@ async fn create_nonce(
             Error::internal("Database operation failed")
         })?
         .ok_or_else(|| {
-            error!(?pubkey_bytes, "Public key not found in database");
+            error!(?key, "Public key not found in database");
             Error::UnregisteredPublicKey
         })
 }
 
-async fn register_key(
-    db: &crate::db::DatabasePool,
+async fn verify_integrity(
+    db: &DatabasePool,
+    keyholder: &ActorRef<KeyHolder>,
+    pubkey: &AuthPublicKey,
+) -> 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: &AuthPublicKey,
+) -> 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_stored_bytes()))
+                    .filter(useragent_client::key_type.eq(pubkey.key_type()))
+                    .set(useragent_client::nonce.eq(useragent_client::nonce + 1))
+                    .returning((useragent_client::id, useragent_client::nonce))
+                    .get_result(conn)
+                    .await
+                    .map_err(|e| {
+                        error!(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: &AuthPublicKey,
-    integrity_tag: Option<Vec<u8>>,
 ) -> Result<(), Error> {
     let pubkey_bytes = pubkey.to_stored_bytes();
     let key_type = pubkey.key_type();
@@ -103,19 +164,40 @@ async fn register_key(
         Error::internal("Database unavailable")
     })?;
 
-    diesel::insert_into(schema::useragent_client::table)
-        .values((
-            schema::useragent_client::public_key.eq(pubkey_bytes),
-            schema::useragent_client::nonce.eq(1),
-            schema::useragent_client::key_type.eq(key_type),
-            schema::useragent_client::pubkey_integrity_tag.eq(integrity_tag),
-        ))
-        .execute(&mut conn)
-        .await
-        .map_err(|e| {
-            error!(error = ?e, "Database error");
-            Error::internal("Database operation failed")
-        })?;
+    conn.transaction(|conn| {
+        Box::pin(async move {
+            const NONCE_START: i32 = 1;
+
+            let id: i32 = diesel::insert_into(useragent_client::table)
+                .values((
+                    useragent_client::public_key.eq(pubkey_bytes),
+                    useragent_client::nonce.eq(NONCE_START),
+                    useragent_client::key_type.eq(key_type),
+                ))
+                .returning(useragent_client::id)
+                .get_result(conn)
+                .await
+                .map_err(|e| {
+                    error!(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(())
 }
@@ -141,15 +223,9 @@ where
         &mut self,
         ChallengeRequest { pubkey }: ChallengeRequest,
     ) -> Result<ChallengeContext, Self::Error> {
-        match self.verify_pubkey_attestation_status(&pubkey).await? {
-            AttestationStatus::Attested | AttestationStatus::Unavailable => {}
-            AttestationStatus::NotAttested => {
-                return Err(Error::InvalidChallengeSolution);
-            }
-        }
+        verify_integrity(&self.conn.db, &self.conn.actors.key_holder, &pubkey).await?;
 
-        let stored_bytes = pubkey.to_stored_bytes();
-        let nonce = create_nonce(&self.conn.db, &stored_bytes, pubkey.key_type()).await?;
+        let nonce = create_nonce(&self.conn.db, &self.conn.actors.key_holder, &pubkey).await?;
 
         self.transport
             .send(Ok(Outbound::AuthChallenge { nonce }))
@@ -189,22 +265,24 @@ where
             return Err(Error::InvalidBootstrapToken);
         }
 
-        let integrity_tag = self
-            .try_sign_pubkey_integrity_tag(&pubkey)
-            .await
-            .map_err(|err| {
-                error!(?err, "Failed to sign user-agent pubkey integrity tag");
-                Error::internal("Failed to sign user-agent pubkey integrity tag")
-            })?;
-
-        register_key(&self.conn.db, &pubkey, integrity_tag).await?;
-
-        self.transport
-            .send(Ok(Outbound::AuthSuccess))
-            .await
-            .map_err(|_| Error::Transport)?;
-
-        Ok(pubkey)
+        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)]
@@ -264,93 +342,3 @@ where
         }
     }
 }
-
-impl<T> AuthContext<'_, T>
-where
-    T: Bi<super::Inbound, Result<super::Outbound, Error>> + Send,
-{
-    async fn try_sign_pubkey_integrity_tag(
-        &self,
-        pubkey: &AuthPublicKey,
-    ) -> Result<Option<Vec<u8>>, Error> {
-        let signed = self
-            .conn
-            .actors
-            .key_holder
-            .ask(SignIntegrityTag {
-                purpose_tag: USERAGENT_INTEGRITY_TAG.to_vec(),
-                data_parts: vec![
-                    (pubkey.key_type() as i32).to_be_bytes().to_vec(),
-                    pubkey.to_stored_bytes(),
-                ],
-            })
-            .await;
-
-        match signed {
-            Ok(tag) => Ok(Some(tag)),
-            Err(SendError::HandlerError(keyholder::Error::NotBootstrapped)) => Ok(None),
-            Err(SendError::HandlerError(err)) => {
-                error!(
-                    ?err,
-                    "Keyholder failed to sign user-agent pubkey integrity tag"
-                );
-                Err(Error::internal(
-                    "Keyholder failed to sign user-agent pubkey integrity tag",
-                ))
-            }
-            Err(err) => {
-                error!(
-                    ?err,
-                    "Failed to contact keyholder for user-agent pubkey integrity tag"
-                );
-                Err(Error::internal(
-                    "Failed to contact keyholder for user-agent pubkey integrity tag",
-                ))
-            }
-        }
-    }
-
-    async fn verify_pubkey_attestation_status(
-        &self,
-        pubkey: &AuthPublicKey,
-    ) -> Result<AttestationStatus, Error> {
-        let stored_tag: Option<Option<Vec<u8>>> = {
-            let mut conn = self.conn.db.get().await.map_err(|e| {
-                error!(error = ?e, "Database pool error");
-                Error::internal("Database unavailable")
-            })?;
-
-            schema::useragent_client::table
-                .filter(schema::useragent_client::public_key.eq(pubkey.to_stored_bytes()))
-                .filter(schema::useragent_client::key_type.eq(pubkey.key_type()))
-                .select(schema::useragent_client::pubkey_integrity_tag)
-                .first::<Option<Vec<u8>>>(&mut conn)
-                .await
-                .optional()
-                .map_err(|e| {
-                    error!(error = ?e, "Database error");
-                    Error::internal("Database operation failed")
-                })?
-        };
-
-        let Some(stored_tag) = stored_tag else {
-            return Err(Error::UnregisteredPublicKey);
-        };
-
-        let Some(expected_tag) = self.try_sign_pubkey_integrity_tag(pubkey).await? else {
-            return Ok(AttestationStatus::Unavailable);
-        };
-
-        match stored_tag {
-            Some(stored_tag) if stored_tag == expected_tag => Ok(AttestationStatus::Attested),
-            Some(_) => {
-                error!("User-agent pubkey integrity tag mismatch");
-                Ok(AttestationStatus::NotAttested)
-            }
-            None => {
-                error!("Missing pubkey integrity tag for registered key while vault is unsealed");
-                Ok(AttestationStatus::NotAttested)
-            }
-        }
-    }
-}
diff --git a/server/crates/arbiter-server/src/actors/user_agent/mod.rs b/server/crates/arbiter-server/src/actors/user_agent/mod.rs
index 3a45cc5..efe3adf 100644
--- a/server/crates/arbiter-server/src/actors/user_agent/mod.rs
+++ b/server/crates/arbiter-server/src/actors/user_agent/mod.rs
@@ -1,18 +1,65 @@
 use crate::{
-    actors::{GlobalActors, client::ClientProfile},
-    db::{self, models::KeyType},
+    actors::{GlobalActors, client::ClientProfile}, crypto::integrity::Integrable, db::{self, models::KeyType}
 };
 
+fn serialize_ecdsa<S>(key: &k256::ecdsa::VerifyingKey, serializer: S) -> Result<S::Ok, S::Error>
+where
+    S: serde::Serializer,
+{
+    // Serialize as hex string for easier debugging (33 bytes compressed SEC1 format)
+    let key = key.to_encoded_point(true);
+    let bytes = key.as_bytes();
+    serializer.serialize_bytes(bytes)
+}
+
+fn deserialize_ecdsa<'de, D>(deserializer: D) -> Result<k256::ecdsa::VerifyingKey, D::Error>
+where
+    D: serde::Deserializer<'de>,
+{
+    struct EcdsaVisitor;
+
+    impl<'de> serde::de::Visitor<'de> for EcdsaVisitor {
+        type Value = k256::ecdsa::VerifyingKey;
+
+        fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+            formatter.write_str("a compressed SEC1-encoded ECDSA public key")
+        }
+
+        fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
+        where
+            E: serde::de::Error,
+        {
+            let point = k256::EncodedPoint::from_bytes(v)
+                .map_err(|_| E::custom("invalid compressed SEC1 format"))?;
+            k256::ecdsa::VerifyingKey::from_encoded_point(&point)
+                .map_err(|_| E::custom("invalid ECDSA public key"))
+        }
+    }
+
+    deserializer.deserialize_bytes(EcdsaVisitor)
+}
+
 /// Abstraction over Ed25519 / ECDSA-secp256k1 / RSA public keys used during the auth handshake.
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, Serialize)]
 pub enum AuthPublicKey {
     Ed25519(ed25519_dalek::VerifyingKey),
     /// Compressed SEC1 public key; signature bytes are raw 64-byte (r||s).
+    #[serde(serialize_with = "serialize_ecdsa", deserialize_with = "deserialize_ecdsa")]
     EcdsaSecp256k1(k256::ecdsa::VerifyingKey),
     /// RSA-2048+ public key (Windows Hello / KeyCredentialManager); signature bytes are PSS+SHA-256.
     Rsa(rsa::RsaPublicKey),
 }
 
+#[derive(Debug, Serialize)]
+pub struct UserAgentCredentials {
+    pub pubkey: AuthPublicKey,
+    pub nonce: i32
+}
+
+impl Integrable for UserAgentCredentials {
+    const KIND: &'static str = "useragent_credentials";
+}
+
 impl AuthPublicKey {
     /// Canonical bytes stored in DB and echoed back in the challenge.
     /// Ed25519: raw 32 bytes. ECDSA: SEC1 compressed 33 bytes. RSA: DER-encoded SPKI.
@@ -91,4 +138,5 @@ pub mod auth;
 pub mod session;
 
 pub use auth::authenticate;
+use serde::Serialize;
 pub use session::UserAgentSession;
diff --git a/server/crates/arbiter-server/src/actors/user_agent/session/connection.rs b/server/crates/arbiter-server/src/actors/user_agent/session/connection.rs
index 382dec5..3017819 100644
--- a/server/crates/arbiter-server/src/actors/user_agent/session/connection.rs
+++ b/server/crates/arbiter-server/src/actors/user_agent/session/connection.rs
@@ -120,6 +120,15 @@ pub enum SignTransactionError {
     Internal,
 }
 
+#[derive(Debug, Error)]
+pub enum GrantMutationError {
+    #[error("Vault is sealed")]
+    VaultSealed,
+
+    #[error("Internal grant mutation error")]
+    Internal,
+}
+
 #[messages]
 impl UserAgentSession {
     #[message]
@@ -331,7 +340,7 @@ impl UserAgentSession {
         &mut self,
         basic: crate::evm::policies::SharedGrantSettings,
         grant: crate::evm::policies::SpecificGrant,
-    ) -> Result<i32, Error> {
+    ) -> Result<i32, GrantMutationError> {
         match self
             .props
             .actors
@@ -342,13 +351,16 @@ impl UserAgentSession {
             Ok(grant_id) => Ok(grant_id),
             Err(err) => {
                 error!(?err, "EVM grant create failed");
-                Err(Error::internal("Failed to create EVM grant"))
+                Err(GrantMutationError::Internal)
             }
         }
     }
 
     #[message]
-    pub(crate) async fn handle_grant_delete(&mut self, grant_id: i32) -> Result<(), Error> {
+    pub(crate) async fn handle_grant_delete(
+        &mut self,
+        grant_id: i32,
+    ) -> Result<(), GrantMutationError> {
         match self
             .props
             .actors
@@ -359,7 +371,7 @@ impl UserAgentSession {
             Ok(()) => Ok(()),
             Err(err) => {
                 error!(?err, "EVM grant delete failed");
-                Err(Error::internal("Failed to delete EVM grant"))
+                Err(GrantMutationError::Internal)
             }
         }
     }
diff --git a/server/crates/arbiter-server/src/crypto/encryption/mod.rs b/server/crates/arbiter-server/src/crypto/encryption/mod.rs
index a3a6d96..22fb807 100644
--- a/server/crates/arbiter-server/src/crypto/encryption/mod.rs
+++ b/server/crates/arbiter-server/src/crypto/encryption/mod.rs
@@ -1 +1,3 @@
 pub mod v1;
+
+pub use v1::*;
\ No newline at end of file
diff --git a/server/crates/arbiter-server/src/crypto/integrity/mod.rs b/server/crates/arbiter-server/src/crypto/integrity/mod.rs
index a3a6d96..22fb807 100644
--- a/server/crates/arbiter-server/src/crypto/integrity/mod.rs
+++ b/server/crates/arbiter-server/src/crypto/integrity/mod.rs
@@ -1 +1,3 @@
 pub mod v1;
+
+pub use v1::*;
\ No newline at end of file
diff --git a/server/crates/arbiter-server/src/crypto/integrity/v1.rs b/server/crates/arbiter-server/src/crypto/integrity/v1.rs
index 2ff4cdd..3fa7d17 100644
--- a/server/crates/arbiter-server/src/crypto/integrity/v1.rs
+++ b/server/crates/arbiter-server/src/crypto/integrity/v1.rs
@@ -1,78 +1,319 @@
-use crate::{crypto::KeyCell, safe_cell::SafeCellHandle as _};
+use crate::{actors::keyholder, crypto::KeyCell,safe_cell::SafeCellHandle as _};
 use chacha20poly1305::Key;
-use hmac::Mac as _;
+use hmac::{Hmac, Mac as _};
+use serde::Serialize;
+use sha2::Sha256;
 
-pub const USERAGENT_INTEGRITY_DERIVE_TAG: &[u8] = "arbiter/useragent/integrity-key/v1".as_bytes();
-pub const USERAGENT_INTEGRITY_TAG: &[u8] = "arbiter/useragent/pubkey-entry/v1".as_bytes();
+use diesel::{ExpressionMethods as _, QueryDsl, dsl::insert_into, sqlite::Sqlite};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use kameo::{actor::ActorRef, error::SendError};
+use sha2::Digest as _;
 
-/// Computes an integrity tag for a specific domain and payload shape.
-pub fn compute_integrity_tag<'a, I>(
-    integrity_key: &mut KeyCell,
-    purpose_tag: &[u8],
-    data_parts: I,
-) -> [u8; 32]
-where
-    I: IntoIterator<Item = &'a [u8]>,
-{
-    type HmacSha256 = hmac::Hmac<sha2::Sha256>;
+use crate::{
+    actors::keyholder::{KeyHolder, SignIntegrity, VerifyIntegrity},
+    db::{
+        self,
+        models::{IntegrityEnvelope, NewIntegrityEnvelope},
+        schema::integrity_envelope,
+    },
+};
 
-    let mut output_tag = [0u8; 32];
-    integrity_key.0.read_inline(|integrity_key_bytes: &Key| {
-        let mut mac = <HmacSha256 as hmac::Mac>::new_from_slice(integrity_key_bytes.as_ref())
-            .expect("HMAC key initialization must not fail for 32-byte key");
-        mac.update(purpose_tag);
-        for data_part in data_parts {
-            mac.update(data_part);
-        }
-        output_tag.copy_from_slice(&mac.finalize().into_bytes());
-    });
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("Database error: {0}")]
+    Database(#[from] db::DatabaseError),
 
-    output_tag
+    #[error("KeyHolder error: {0}")]
+    Keyholder(#[from] keyholder::Error),
+
+    #[error("KeyHolder mailbox error")]
+    KeyholderSend,
+
+    #[error("Integrity envelope is missing for entity {entity_kind}")]
+    MissingEnvelope { entity_kind: &'static str },
+
+    #[error(
+        "Integrity payload version mismatch for entity {entity_kind}: expected {expected}, found {found}"
+    )]
+    PayloadVersionMismatch {
+        entity_kind: &'static str,
+        expected: i32,
+        found: i32,
+    },
+
+    #[error("Integrity MAC mismatch for entity {entity_kind}")]
+    MacMismatch { entity_kind: &'static str },
+
+    #[error("Payload serialization error: {0}")]
+    PayloadSerialization(#[from] postcard::Error),
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum AttestationStatus {
+    Attested,
+    Unavailable,
+}
+
+pub const CURRENT_PAYLOAD_VERSION: i32 = 1;
+pub const INTEGRITY_SUBKEY_TAG: &[u8] = b"arbiter/db-integrity-key/v1";
+
+pub type HmacSha256 = Hmac<Sha256>;
+
+pub trait Integrable: Serialize {
+    const KIND: &'static str;
+    const VERSION: i32 = 1;
+}
+
+fn payload_hash(payload: &[u8]) -> [u8; 32] {
+    Sha256::digest(payload).into()
+}
+
+fn push_len_prefixed(out: &mut Vec<u8>, bytes: &[u8]) {
+    out.extend_from_slice(&(bytes.len() as u32).to_be_bytes());
+    out.extend_from_slice(bytes);
+}
+
+fn build_mac_input(
+    entity_kind: &str,
+    entity_id: &[u8],
+    payload_version: i32,
+    payload_hash: &[u8; 32],
+) -> Vec<u8> {
+    let mut out = Vec::with_capacity(8 + entity_kind.len() + entity_id.len() + 32);
+    push_len_prefixed(&mut out, entity_kind.as_bytes());
+    push_len_prefixed(&mut out, entity_id);
+    out.extend_from_slice(&payload_version.to_be_bytes());
+    out.extend_from_slice(payload_hash);
+    out
+}
+
+pub trait IntoId {
+    fn into_id(self) -> Vec<u8>;
+}
+
+impl IntoId for i32 {
+    fn into_id(self) -> Vec<u8> {
+        self.to_be_bytes().to_vec()
+    }
+}
+
+impl IntoId for &'_ [u8] {
+    fn into_id(self) -> Vec<u8> {
+        self.to_vec()
+    }
+}
+
+pub async fn sign_entity<E: Integrable>(
+    conn: &mut impl AsyncConnection<Backend = Sqlite>,
+    keyholder: &ActorRef<KeyHolder>,
+    entity: &E,
+    entity_id: impl IntoId,
+) -> Result<(), Error> {
+    let payload = postcard::to_stdvec(entity)?;
+    let payload_hash = payload_hash(&payload);
+
+    let entity_id = entity_id.into_id();
+
+    let mac_input = build_mac_input(E::KIND, &entity_id, E::VERSION, &payload_hash);
+
+    let (key_version, mac) = keyholder
+        .ask(SignIntegrity { mac_input })
+        .await
+        .map_err(|err| match err {
+            kameo::error::SendError::HandlerError(inner) => Error::Keyholder(inner),
+            _ => Error::KeyholderSend,
+        })?;
+
+    insert_into(integrity_envelope::table)
+        .values(NewIntegrityEnvelope {
+            entity_kind: E::KIND.to_owned(),
+            entity_id: entity_id,
+            payload_version: E::VERSION ,
+            key_version,
+            mac: mac.to_vec(),
+        })
+        .on_conflict((
+            integrity_envelope::entity_id,
+            integrity_envelope::entity_kind,
+        ))
+        .do_update()
+        .set((
+            integrity_envelope::payload_version.eq(E::VERSION),
+            integrity_envelope::key_version.eq(key_version),
+            integrity_envelope::mac.eq(mac),
+        ))
+        .execute(conn)
+        .await
+        .map_err(db::DatabaseError::from)?;
+
+    Ok(())
+}
+
+pub async fn verify_entity<E: Integrable>(
+    conn: &mut impl AsyncConnection<Backend = Sqlite>,
+    keyholder: &ActorRef<KeyHolder>,
+    entity: &E,
+    entity_id: impl IntoId,
+) -> Result<AttestationStatus, Error> {
+    let entity_id = entity_id.into_id();
+    let envelope: IntegrityEnvelope = integrity_envelope::table
+        .filter(integrity_envelope::entity_kind.eq(E::KIND))
+        .filter(integrity_envelope::entity_id.eq(&entity_id))
+        .first(conn)
+        .await
+        .map_err(|err| match err {
+            diesel::result::Error::NotFound => Error::MissingEnvelope { entity_kind: E::KIND },
+            other => Error::Database(db::DatabaseError::from(other)),
+        })?;
+
+    if envelope.payload_version != E::VERSION {
+        return Err(Error::PayloadVersionMismatch {
+            entity_kind: E::KIND,
+            expected: E::VERSION,
+            found: envelope.payload_version,
+        });
+    }
+
+    let payload = postcard::to_stdvec(entity)?;
+    let payload_hash = payload_hash(&payload);
+    let mac_input = build_mac_input(
+        E::KIND,
+        &entity_id,
+        envelope.payload_version,
+        &payload_hash,
+    );
+
+    let result = keyholder
+        .ask(VerifyIntegrity {
+            mac_input,
+            expected_mac: envelope.mac,
+            key_version: envelope.key_version,
+        })
+        .await
+        ;
+
+    match result {
+        Ok(true) => Ok(AttestationStatus::Attested),
+        Ok(false) => Err(Error::MacMismatch { entity_kind: E::KIND }),
+        Err(SendError::HandlerError(keyholder::Error::NotBootstrapped)) => Ok(AttestationStatus::Unavailable),
+        Err(_) => Err(Error::KeyholderSend),
+    }
 }
 
 #[cfg(test)]
 mod tests {
+    use diesel::{ExpressionMethods as _, QueryDsl};
+    use diesel_async::RunQueryDsl;
+    use kameo::{actor::ActorRef, prelude::Spawn};
+
     use crate::{
-        crypto::{derive_key, encryption::v1::generate_salt},
+        actors::keyholder::{Bootstrap, KeyHolder},
+        db::{self, schema},
         safe_cell::{SafeCell, SafeCellHandle as _},
     };
 
-    use super::{USERAGENT_INTEGRITY_TAG, compute_integrity_tag};
+    use super::{Error, Integrable, sign_entity, verify_entity};
 
-    #[test]
-    pub fn integrity_tag_deterministic() {
-        let salt = generate_salt();
-        let mut integrity_key = derive_key(SafeCell::new(b"password".to_vec()), &salt);
-        let key_type = 1i32.to_be_bytes();
-        let t1 = compute_integrity_tag(
-            &mut integrity_key,
-            USERAGENT_INTEGRITY_TAG,
-            [key_type.as_slice(), b"pubkey".as_ref()],
-        );
-        let t2 = compute_integrity_tag(
-            &mut integrity_key,
-            USERAGENT_INTEGRITY_TAG,
-            [key_type.as_slice(), b"pubkey".as_ref()],
-        );
-        assert_eq!(t1, t2);
+    #[derive(Clone, serde::Serialize)]
+    struct DummyEntity {
+        payload_version: i32,
+        payload: Vec<u8>,
     }
 
-    #[test]
-    pub fn integrity_tag_changes_with_payload() {
-        let salt = generate_salt();
-        let mut integrity_key = derive_key(SafeCell::new(b"password".to_vec()), &salt);
-        let key_type_1 = 1i32.to_be_bytes();
-        let key_type_2 = 2i32.to_be_bytes();
-        let t1 = compute_integrity_tag(
-            &mut integrity_key,
-            USERAGENT_INTEGRITY_TAG,
-            [key_type_1.as_slice(), b"pubkey".as_ref()],
-        );
-        let t2 = compute_integrity_tag(
-            &mut integrity_key,
-            USERAGENT_INTEGRITY_TAG,
-            [key_type_2.as_slice(), b"pubkey".as_ref()],
-        );
-        assert_ne!(t1, t2);
+    impl Integrable for DummyEntity {
+        const KIND: &'static str = "dummy_entity";
+    }
+
+    async fn bootstrapped_keyholder(db: &db::DatabasePool) -> ActorRef<KeyHolder> {
+        let actor = KeyHolder::spawn(KeyHolder::new(db.clone()).await.unwrap());
+        actor
+            .ask(Bootstrap {
+                seal_key_raw: SafeCell::new(b"integrity-test-seal-key".to_vec()),
+            })
+            .await
+            .unwrap();
+        actor
+    }
+
+    #[tokio::test]
+    async fn sign_writes_envelope_and_verify_passes() {
+        let db = db::create_test_pool().await;
+        let keyholder = bootstrapped_keyholder(&db).await;
+        let mut conn = db.get().await.unwrap();
+
+        const ENTITY_ID: &[u8] = b"entity-id-7";
+
+        let entity = DummyEntity {
+            payload_version: 1,
+            payload: b"payload-v1".to_vec(),
+        };
+
+        sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID).await.unwrap();
+
+        let count: i64 = schema::integrity_envelope::table
+            .filter(schema::integrity_envelope::entity_kind.eq("dummy_entity"))
+            .filter(schema::integrity_envelope::entity_id.eq(ENTITY_ID))
+            .count()
+            .get_result(&mut conn)
+            .await
+            .unwrap();
+
+        assert_eq!(count, 1, "envelope row must be created exactly once");
+        verify_entity(&mut conn, &keyholder, &entity, ENTITY_ID).await.unwrap();
+    }
+
+    #[tokio::test]
+    async fn tampered_mac_fails_verification() {
+        let db = db::create_test_pool().await;
+        let keyholder = bootstrapped_keyholder(&db).await;
+        let mut conn = db.get().await.unwrap();
+
+        const ENTITY_ID: &[u8] = b"entity-id-11";
+
+        let entity = DummyEntity {
+            payload_version: 1,
+            payload: b"payload-v1".to_vec(),
+        };
+
+        sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID).await.unwrap();
+
+        diesel::update(schema::integrity_envelope::table)
+            .filter(schema::integrity_envelope::entity_kind.eq("dummy_entity"))
+            .filter(schema::integrity_envelope::entity_id.eq(ENTITY_ID))
+            .set(schema::integrity_envelope::mac.eq(vec![0u8; 32]))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+
+        let err = verify_entity(&mut conn, &keyholder, &entity, ENTITY_ID)
+            .await
+            .unwrap_err();
+        assert!(matches!(err, Error::MacMismatch { .. }));
+    }
+
+    #[tokio::test]
+    async fn changed_payload_fails_verification() {
+        let db = db::create_test_pool().await;
+        let keyholder = bootstrapped_keyholder(&db).await;
+        let mut conn = db.get().await.unwrap();
+
+        const ENTITY_ID: &[u8] = b"entity-id-21";
+
+        let entity = DummyEntity {
+            payload_version: 1,
+            payload: b"payload-v1".to_vec(),
+        };
+
+        sign_entity(&mut conn, &keyholder, &entity, ENTITY_ID).await.unwrap();
+
+        let tampered = DummyEntity {
+            payload: b"payload-v1-but-tampered".to_vec(),
+            ..entity
+        };
+
+        let err = verify_entity(&mut conn, &keyholder, &tampered, ENTITY_ID)
+            .await
+            .unwrap_err();
+        assert!(matches!(err, Error::MacMismatch { .. }));
     }
 }
diff --git a/server/crates/arbiter-server/src/db/models.rs b/server/crates/arbiter-server/src/db/models.rs
index 6fb171c..f558072 100644
--- a/server/crates/arbiter-server/src/db/models.rs
+++ b/server/crates/arbiter-server/src/db/models.rs
@@ -5,7 +5,7 @@ use crate::db::schema::{
     self, aead_encrypted, arbiter_settings, evm_basic_grant, evm_ether_transfer_grant,
     evm_ether_transfer_grant_target, evm_ether_transfer_limit, evm_token_transfer_grant,
     evm_token_transfer_log, evm_token_transfer_volume_limit, evm_transaction_log, evm_wallet,
-    root_key_history, tls_history,
+    integrity_envelope, root_key_history, tls_history,
 };
 use chrono::{DateTime, Utc};
 use diesel::{prelude::*, sqlite::Sqlite};
@@ -242,7 +242,6 @@ pub struct UseragentClient {
     pub id: i32,
     pub nonce: i32,
     pub public_key: Vec<u8>,
-    pub pubkey_integrity_tag: Option<Vec<u8>>,
     pub created_at: SqliteTimestamp,
     pub updated_at: SqliteTimestamp,
     pub key_type: KeyType,
@@ -377,3 +376,22 @@ pub struct EvmTokenTransferLog {
     pub value: Vec<u8>,
     pub created_at: SqliteTimestamp,
 }
+
+#[derive(Models, Queryable, Debug, Insertable, Selectable)]
+#[diesel(table_name = integrity_envelope, check_for_backend(Sqlite))]
+#[view(
+    NewIntegrityEnvelope,
+    derive(Insertable),
+    omit(id, signed_at, created_at),
+    attributes_with = "deriveless"
+)]
+pub struct IntegrityEnvelope {
+    pub id: i32,
+    pub entity_kind: String,
+    pub entity_id: Vec<u8>,
+    pub payload_version: i32,
+    pub key_version: i32,
+    pub mac: Vec<u8>,
+    pub signed_at: SqliteTimestamp,
+    pub created_at: SqliteTimestamp,
+}
diff --git a/server/crates/arbiter-server/src/db/schema.rs b/server/crates/arbiter-server/src/db/schema.rs
index 88bdef3..c9b980c 100644
--- a/server/crates/arbiter-server/src/db/schema.rs
+++ b/server/crates/arbiter-server/src/db/schema.rs
@@ -139,6 +139,19 @@ diesel::table! {
     }
 }
 
+diesel::table! {
+    integrity_envelope (id) {
+        id -> Integer,
+        entity_kind -> Text,
+        entity_id -> Binary,
+        payload_version -> Integer,
+        key_version -> Integer,
+        mac -> Binary,
+        signed_at -> Integer,
+        created_at -> Integer,
+    }
+}
+
 diesel::table! {
     program_client (id) {
         id -> Integer,
@@ -178,7 +191,6 @@ diesel::table! {
         id -> Integer,
         nonce -> Integer,
         public_key -> Binary,
-        pubkey_integrity_tag -> Nullable<Binary>,
         key_type -> Integer,
         created_at -> Integer,
         updated_at -> Integer,
@@ -220,6 +232,7 @@ diesel::allow_tables_to_appear_in_same_query!(
     evm_transaction_log,
     evm_wallet,
     evm_wallet_access,
+    integrity_envelope,
     program_client,
     root_key_history,
     tls_history,
diff --git a/server/crates/arbiter-server/src/evm/mod.rs b/server/crates/arbiter-server/src/evm/mod.rs
index d840d81..6727650 100644
--- a/server/crates/arbiter-server/src/evm/mod.rs
+++ b/server/crates/arbiter-server/src/evm/mod.rs
@@ -8,8 +8,11 @@ use alloy::{
 use chrono::Utc;
 use diesel::{ExpressionMethods as _, QueryDsl as _, QueryResult, insert_into, sqlite::Sqlite};
 use diesel_async::{AsyncConnection, RunQueryDsl};
+use kameo::actor::ActorRef;
 
 use crate::{
+    actors::keyholder::KeyHolder,
+    crypto::integrity,
     db::{
         self, DatabaseError,
         models::{
@@ -18,7 +21,7 @@ use crate::{
         schema::{self, evm_transaction_log},
     },
     evm::policies::{
-        DatabaseID, EvalContext, EvalViolation, FullGrant, Grant, Policy, SharedGrantSettings,
+        DatabaseID, EvalContext, EvalViolation, Grant, Policy, CombinedSettings, SharedGrantSettings,
         SpecificGrant, SpecificMeaning, ether_transfer::EtherTransfer,
         token_transfers::TokenTransfer,
     },
@@ -36,6 +39,9 @@ pub enum PolicyError {
     Violations(Vec<EvalViolation>),
     #[error("No matching grant found")]
     NoMatchingGrant,
+
+    #[error("Integrity error: {0}")]
+    Integrity(#[from] integrity::Error),
 }
 
 #[derive(Debug, thiserror::Error)]
@@ -57,6 +63,15 @@ pub enum AnalyzeError {
     UnsupportedTransactionType,
 }
 
+#[derive(Debug, thiserror::Error)]
+pub enum ListError {
+    #[error("Database error")]
+    Database(#[from] crate::db::DatabaseError),
+
+    #[error("Integrity verification failed for grant")]
+    Integrity(#[from] integrity::Error),
+}
+
 /// Controls whether a transaction should be executed or only validated
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum RunKind {
@@ -115,6 +130,7 @@ 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>,
 }
 
 impl Engine {
@@ -123,7 +139,10 @@ impl Engine {
         context: EvalContext,
         meaning: &P::Meaning,
         run_kind: RunKind,
-    ) -> Result<(), PolicyError> {
+    ) -> Result<(), PolicyError>
+    where
+        P::Settings: Clone,
+    {
         let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
 
         let grant = P::try_find_grant(&context, &mut conn)
@@ -131,10 +150,16 @@ impl Engine {
             .map_err(DatabaseError::from)?
             .ok_or(PolicyError::NoMatchingGrant)?;
 
-        let mut violations =
-            check_shared_constraints(&context, &grant.shared, grant.shared_grant_id, &mut conn)
-                .await
-                .map_err(DatabaseError::from)?;
+        integrity::verify_entity(&mut conn, &self.keyholder, &grant.settings, grant.id).await?;
+
+        let mut violations = check_shared_constraints(
+            &context,
+            &grant.settings.shared,
+            grant.common_settings_id,
+            &mut conn,
+        )
+        .await
+        .map_err(DatabaseError::from)?;
         violations.extend(
             P::evaluate(&context, meaning, &grant, &mut conn)
                 .await
@@ -143,12 +168,14 @@ impl Engine {
 
         if !violations.is_empty() {
             return Err(PolicyError::Violations(violations));
-        } else if run_kind == RunKind::Execution {
+        }
+
+        if run_kind == RunKind::Execution {
             conn.transaction(|conn| {
                 Box::pin(async move {
                     let log_id: i32 = insert_into(evm_transaction_log::table)
                         .values(&NewEvmTransactionLog {
-                            grant_id: grant.shared_grant_id,
+                            grant_id: grant.common_settings_id,
                             wallet_access_id: context.target.id,
                             chain_id: context.chain as i32,
                             eth_value: utils::u256_to_bytes(context.value).to_vec(),
@@ -172,15 +199,19 @@ impl Engine {
 }
 
 impl Engine {
-    pub fn new(db: db::DatabasePool) -> Self {
-        Self { db }
+    pub fn new(db: db::DatabasePool, keyholder: ActorRef<KeyHolder>) -> Self {
+        Self { db, keyholder }
     }
 
     pub async fn create_grant<P: Policy>(
         &self,
-        full_grant: FullGrant<P::Settings>,
-    ) -> Result<i32, DatabaseError> {
+        full_grant: CombinedSettings<P::Settings>,
+    ) -> Result<i32, DatabaseError>
+    where
+        P::Settings: Clone,
+    {
         let mut conn = self.db.get().await?;
+        let keyholder = self.keyholder.clone();
 
         let id = conn
             .transaction(|conn| {
@@ -189,25 +220,25 @@ impl Engine {
 
                     let basic_grant: EvmBasicGrant = insert_into(evm_basic_grant::table)
                         .values(&NewEvmBasicGrant {
-                            chain_id: full_grant.basic.chain as i32,
-                            wallet_access_id: full_grant.basic.wallet_access_id,
-                            valid_from: full_grant.basic.valid_from.map(SqliteTimestamp),
-                            valid_until: full_grant.basic.valid_until.map(SqliteTimestamp),
+                            chain_id: full_grant.shared.chain as i32,
+                            wallet_access_id: full_grant.shared.wallet_access_id,
+                            valid_from: full_grant.shared.valid_from.map(SqliteTimestamp),
+                            valid_until: full_grant.shared.valid_until.map(SqliteTimestamp),
                             max_gas_fee_per_gas: full_grant
-                                .basic
+                                .shared
                                 .max_gas_fee_per_gas
                                 .map(|fee| utils::u256_to_bytes(fee).to_vec()),
                             max_priority_fee_per_gas: full_grant
-                                .basic
+                                .shared
                                 .max_priority_fee_per_gas
                                 .map(|fee| utils::u256_to_bytes(fee).to_vec()),
                             rate_limit_count: full_grant
-                                .basic
+                                .shared
                                 .rate_limit
                                 .as_ref()
                                 .map(|rl| rl.count as i32),
                             rate_limit_window_secs: full_grant
-                                .basic
+                                .shared
                                 .rate_limit
                                 .as_ref()
                                 .map(|rl| rl.window.num_seconds() as i32),
@@ -217,7 +248,18 @@ impl Engine {
                         .get_result(conn)
                         .await?;
 
-                    P::create_grant(&basic_grant, &full_grant.specific, conn).await
+                    P::create_grant(&basic_grant, &full_grant.specific, conn).await?;
+
+                    integrity::sign_entity(
+                        conn,
+                        &keyholder,
+                        &full_grant,
+                    basic_grant.id,
+                    )
+                    .await
+                    .map_err(|_| diesel::result::Error::RollbackTransaction)?;
+
+                    QueryResult::Ok(basic_grant.id)
                 })
             })
             .await?;
@@ -225,33 +267,36 @@ impl Engine {
         Ok(id)
     }
 
-    pub async fn list_all_grants(&self) -> Result<Vec<Grant<SpecificGrant>>, DatabaseError> {
-        let mut conn = self.db.get().await?;
+    async fn list_one_kind<Kind: Policy, Y>(
+        &self,
+        conn: &mut impl AsyncConnection<Backend = Sqlite>,
+    ) -> Result<impl Iterator<Item = Grant<Y>>, ListError>
+    where
+        Y: From<Kind::Settings>,
+    {
+        let all_grants = Kind::find_all_grants(conn)
+            .await
+            .map_err(DatabaseError::from)?;
+
+        // Verify integrity of all grants before returning any results
+        for grant in &all_grants {
+            integrity::verify_entity(conn, &self.keyholder, &grant.settings, grant.id).await?;
+        }
+
+        Ok(all_grants.into_iter().map(|g| Grant {
+            id: g.id,
+            common_settings_id: g.common_settings_id,
+            settings: g.settings.generalize(),
+        }))
+    }
+
+    pub async fn list_all_grants(&self) -> Result<Vec<Grant<SpecificGrant>>, ListError> {
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
 
         let mut grants: Vec<Grant<SpecificGrant>> = Vec::new();
 
-        grants.extend(
-            EtherTransfer::find_all_grants(&mut conn)
-                .await?
-                .into_iter()
-                .map(|g| Grant {
-                    id: g.id,
-                    shared_grant_id: g.shared_grant_id,
-                    shared: g.shared,
-                    settings: SpecificGrant::EtherTransfer(g.settings),
-                }),
-        );
-        grants.extend(
-            TokenTransfer::find_all_grants(&mut conn)
-                .await?
-                .into_iter()
-                .map(|g| Grant {
-                    id: g.id,
-                    shared_grant_id: g.shared_grant_id,
-                    shared: g.shared,
-                    settings: SpecificGrant::TokenTransfer(g.settings),
-                }),
-        );
+        grants.extend(self.list_one_kind::<EtherTransfer, _>(&mut conn).await?);
+        grants.extend(self.list_one_kind::<TokenTransfer, _>(&mut conn).await?);
 
         Ok(grants)
     }
diff --git a/server/crates/arbiter-server/src/evm/policies.rs b/server/crates/arbiter-server/src/evm/policies.rs
index f0e7796..d69af22 100644
--- a/server/crates/arbiter-server/src/evm/policies.rs
+++ b/server/crates/arbiter-server/src/evm/policies.rs
@@ -7,11 +7,11 @@ use diesel::{
 };
 use diesel_async::{AsyncConnection, RunQueryDsl};
 
+use serde::Serialize;
 use thiserror::Error;
 
 use crate::{
-    db::models::{self, EvmBasicGrant, EvmWalletAccess},
-    evm::utils,
+    crypto::integrity::v1::Integrable, db::models::{self, EvmBasicGrant, EvmWalletAccess}, evm::utils
 };
 
 pub mod ether_transfer;
@@ -59,16 +59,15 @@ pub enum EvalViolation {
 
 pub type DatabaseID = i32;
 
-#[derive(Debug)]
+#[derive(Debug, Serialize)]
 pub struct Grant<PolicySettings> {
     pub id: DatabaseID,
-    pub shared_grant_id: DatabaseID, // ID of the basic grant for shared-logic checks like rate limits and validity periods
-    pub shared: SharedGrantSettings,
-    pub settings: PolicySettings,
+    pub common_settings_id: DatabaseID, // ID of the basic grant for shared-logic checks like rate limits and validity periods
+    pub settings: CombinedSettings<PolicySettings>,
 }
 
 pub trait Policy: Sized {
-    type Settings: Send + Sync + 'static + Into<SpecificGrant>;
+    type Settings: Send + Sync + 'static + Into<SpecificGrant> + Integrable;
     type Meaning: Display + std::fmt::Debug + Send + Sync + 'static + Into<SpecificMeaning>;
 
     fn analyze(context: &EvalContext) -> Option<Self::Meaning>;
@@ -124,19 +123,19 @@ pub enum SpecificMeaning {
     TokenTransfer(token_transfers::Meaning),
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize)]
 pub struct TransactionRateLimit {
     pub count: u32,
     pub window: Duration,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize)]
 pub struct VolumeRateLimit {
     pub max_volume: U256,
     pub window: Duration,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize)]
 pub struct SharedGrantSettings {
     pub wallet_access_id: i32,
     pub chain: ChainId,
@@ -151,7 +150,7 @@ pub struct SharedGrantSettings {
 }
 
 impl SharedGrantSettings {
-    fn try_from_model(model: EvmBasicGrant) -> QueryResult<Self> {
+    pub(crate) fn try_from_model(model: EvmBasicGrant) -> QueryResult<Self> {
         Ok(Self {
             wallet_access_id: model.wallet_access_id,
             chain: model.chain_id as u64, // safe because chain_id is stored as i32 but is guaranteed to be a valid ChainId by the API when creating grants
@@ -197,7 +196,23 @@ pub enum SpecificGrant {
     TokenTransfer(token_transfers::Settings),
 }
 
-pub struct FullGrant<PolicyGrant> {
-    pub basic: SharedGrantSettings,
+#[derive(Debug, Serialize)]
+pub struct CombinedSettings<PolicyGrant> {
+    pub shared: SharedGrantSettings,
     pub specific: PolicyGrant,
 }
+
+impl<P> CombinedSettings<P> {
+    pub fn generalize<Y: From<P>>(self) -> CombinedSettings<Y> {
+        CombinedSettings {
+            shared: self.shared,
+            specific: self.specific.into(),
+        }
+    }
+}
+
+impl<P: Integrable> Integrable for CombinedSettings<P> {
+    const KIND: &'static str = P::KIND;
+    const VERSION: i32 = P::VERSION;
+}
+
diff --git a/server/crates/arbiter-server/src/evm/policies/ether_transfer/mod.rs b/server/crates/arbiter-server/src/evm/policies/ether_transfer/mod.rs
index d419b59..57a38dd 100644
--- a/server/crates/arbiter-server/src/evm/policies/ether_transfer/mod.rs
+++ b/server/crates/arbiter-server/src/evm/policies/ether_transfer/mod.rs
@@ -8,13 +8,14 @@ use diesel::sqlite::Sqlite;
 use diesel::{ExpressionMethods, JoinOnDsl, prelude::*};
 use diesel_async::{AsyncConnection, RunQueryDsl};
 
+use crate::crypto::integrity::v1::Integrable;
 use crate::db::models::{
     EvmBasicGrant, EvmEtherTransferGrant, EvmEtherTransferGrantTarget, EvmEtherTransferLimit,
     NewEvmEtherTransferLimit, SqliteTimestamp,
 };
 use crate::db::schema::{evm_basic_grant, evm_ether_transfer_limit, evm_transaction_log};
 use crate::evm::policies::{
-    Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning, VolumeRateLimit,
+    CombinedSettings, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning, VolumeRateLimit,
 };
 use crate::{
     db::{
@@ -51,11 +52,14 @@ impl From<Meaning> for SpecificMeaning {
 }
 
 // A grant for ether transfers, which can be scoped to specific target addresses and volume limits
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, serde::Serialize)]
 pub struct Settings {
     pub target: Vec<Address>,
     pub limit: VolumeRateLimit,
 }
+impl Integrable for Settings {
+    const KIND: &'static str = "EtherTransfer";
+}
 
 impl From<Settings> for SpecificGrant {
     fn from(val: Settings) -> SpecificGrant {
@@ -95,17 +99,17 @@ async fn check_rate_limits(
     db: &mut impl AsyncConnection<Backend = Sqlite>,
 ) -> QueryResult<Vec<EvalViolation>> {
     let mut violations = Vec::new();
-    let window = grant.settings.limit.window;
+    let window = grant.settings.specific.limit.window;
 
     let past_transaction = query_relevant_past_transaction(grant.id, window, db).await?;
 
-    let window_start = chrono::Utc::now() - grant.settings.limit.window;
+    let window_start = chrono::Utc::now() - grant.settings.specific.limit.window;
     let prospective_cumulative_volume: U256 = past_transaction
         .iter()
         .filter(|(_, timestamp)| timestamp >= &window_start)
         .fold(current_transfer_value, |acc, (value, _)| acc + *value);
 
-    if prospective_cumulative_volume > grant.settings.limit.max_volume {
+    if prospective_cumulative_volume > grant.settings.specific.limit.max_volume {
         violations.push(EvalViolation::VolumetricLimitExceeded);
     }
 
@@ -138,7 +142,7 @@ impl Policy for EtherTransfer {
         let mut violations = Vec::new();
 
         // Check if the target address is within the grant's allowed targets
-        if !grant.settings.target.contains(&meaning.to) {
+        if !grant.settings.specific.target.contains(&meaning.to) {
             violations.push(EvalViolation::InvalidTarget { target: meaning.to });
         }
 
@@ -247,9 +251,11 @@ impl Policy for EtherTransfer {
 
         Ok(Some(Grant {
             id: grant.id,
-            shared_grant_id: grant.basic_grant_id,
-            shared: SharedGrantSettings::try_from_model(basic_grant)?,
-            settings,
+            common_settings_id: grant.basic_grant_id,
+            settings: CombinedSettings {
+                shared: SharedGrantSettings::try_from_model(basic_grant)?,
+                specific: settings,
+            },
         }))
     }
 
@@ -327,15 +333,17 @@ impl Policy for EtherTransfer {
 
                 Ok(Grant {
                     id: specific.id,
-                    shared_grant_id: specific.basic_grant_id,
-                    shared: SharedGrantSettings::try_from_model(basic)?,
-                    settings: Settings {
-                        target: targets,
-                        limit: VolumeRateLimit {
-                            max_volume: utils::try_bytes_to_u256(&limit.max_volume).map_err(
-                                |e| diesel::result::Error::DeserializationError(Box::new(e)),
-                            )?,
-                            window: Duration::seconds(limit.window_secs as i64),
+                    common_settings_id: specific.basic_grant_id,
+                    settings: CombinedSettings {
+                        shared: SharedGrantSettings::try_from_model(basic)?,
+                        specific: Settings {
+                            target: targets,
+                            limit: VolumeRateLimit {
+                                max_volume: utils::try_bytes_to_u256(&limit.max_volume).map_err(
+                                    |e| diesel::result::Error::DeserializationError(Box::new(e)),
+                                )?,
+                                window: Duration::seconds(limit.window_secs as i64),
+                            },
                         },
                     },
                 })
diff --git a/server/crates/arbiter-server/src/evm/policies/ether_transfer/tests.rs b/server/crates/arbiter-server/src/evm/policies/ether_transfer/tests.rs
index 9ba48be..ab4e8f0 100644
--- a/server/crates/arbiter-server/src/evm/policies/ether_transfer/tests.rs
+++ b/server/crates/arbiter-server/src/evm/policies/ether_transfer/tests.rs
@@ -11,7 +11,10 @@ use crate::db::{
     schema::{evm_basic_grant, evm_transaction_log},
 };
 use crate::evm::{
-    policies::{EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings, VolumeRateLimit},
+    policies::{
+        CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
+        VolumeRateLimit,
+    },
     utils,
 };
 
@@ -108,9 +111,11 @@ async fn evaluate_passes_for_allowed_target() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
-        shared: shared(),
-        settings: make_settings(vec![ALLOWED], 1_000_000),
+        common_settings_id: 999,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: make_settings(vec![ALLOWED], 1_000_000),
+        },
     };
     let context = ctx(ALLOWED, U256::from(100u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -127,9 +132,11 @@ async fn evaluate_rejects_disallowed_target() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
-        shared: shared(),
-        settings: make_settings(vec![ALLOWED], 1_000_000),
+        common_settings_id: 999,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: make_settings(vec![ALLOWED], 1_000_000),
+        },
     };
     let context = ctx(OTHER, U256::from(100u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -167,9 +174,11 @@ async fn evaluate_passes_when_volume_within_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
-        shared: shared(),
-        settings,
+        common_settings_id: basic.id,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: settings,
+        },
     };
     let context = ctx(ALLOWED, U256::from(100u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -207,9 +216,11 @@ async fn evaluate_rejects_volume_over_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
-        shared: shared(),
-        settings,
+        common_settings_id: basic.id,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: settings,
+        },
     };
     let context = ctx(ALLOWED, U256::from(1u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -248,9 +259,11 @@ async fn evaluate_passes_at_exactly_volume_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
-        shared: shared(),
-        settings,
+        common_settings_id: basic.id,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: settings,
+        },
     };
     let context = ctx(ALLOWED, U256::from(100u64));
     let m = EtherTransfer::analyze(&context).unwrap();
@@ -282,8 +295,11 @@ async fn try_find_grant_roundtrip() {
 
     assert!(found.is_some());
     let g = found.unwrap();
-    assert_eq!(g.settings.target, vec![ALLOWED]);
-    assert_eq!(g.settings.limit.max_volume, U256::from(1_000_000u64));
+    assert_eq!(g.settings.specific.target, vec![ALLOWED]);
+    assert_eq!(
+        g.settings.specific.limit.max_volume,
+        U256::from(1_000_000u64)
+    );
 }
 
 #[tokio::test]
@@ -347,7 +363,7 @@ async fn find_all_grants_excludes_revoked() {
 
     let all = EtherTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 1);
-    assert_eq!(all[0].settings.target, vec![ALLOWED]);
+    assert_eq!(all[0].settings.specific.target, vec![ALLOWED]);
 }
 
 #[tokio::test]
@@ -363,8 +379,11 @@ async fn find_all_grants_multiple_targets() {
 
     let all = EtherTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 1);
-    assert_eq!(all[0].settings.target.len(), 2);
-    assert_eq!(all[0].settings.limit.max_volume, U256::from(1_000_000u64));
+    assert_eq!(all[0].settings.specific.target.len(), 2);
+    assert_eq!(
+        all[0].settings.specific.limit.max_volume,
+        U256::from(1_000_000u64)
+    );
 }
 
 #[tokio::test]
diff --git a/server/crates/arbiter-server/src/evm/policies/token_transfers/mod.rs b/server/crates/arbiter-server/src/evm/policies/token_transfers/mod.rs
index cef49d9..0a1253c 100644
--- a/server/crates/arbiter-server/src/evm/policies/token_transfers/mod.rs
+++ b/server/crates/arbiter-server/src/evm/policies/token_transfers/mod.rs
@@ -10,11 +10,8 @@ use diesel::dsl::{auto_type, insert_into};
 use diesel::sqlite::Sqlite;
 use diesel::{ExpressionMethods, prelude::*};
 use diesel_async::{AsyncConnection, RunQueryDsl};
+use serde::Serialize;
 
-use crate::db::models::{
-    EvmBasicGrant, EvmTokenTransferGrant, EvmTokenTransferVolumeLimit, NewEvmTokenTransferGrant,
-    NewEvmTokenTransferLog, NewEvmTokenTransferVolumeLimit, SqliteTimestamp,
-};
 use crate::db::schema::{
     evm_basic_grant, evm_token_transfer_grant, evm_token_transfer_log,
     evm_token_transfer_volume_limit,
@@ -26,6 +23,15 @@ use crate::evm::{
     },
     utils,
 };
+use crate::{
+    crypto::integrity::Integrable,
+    db::models::{
+        EvmBasicGrant, EvmTokenTransferGrant, EvmTokenTransferVolumeLimit,
+        NewEvmTokenTransferGrant, NewEvmTokenTransferLog, NewEvmTokenTransferVolumeLimit,
+        SqliteTimestamp,
+    },
+    evm::policies::CombinedSettings,
+};
 
 use super::{DatabaseID, EvalContext, EvalViolation};
 
@@ -38,9 +44,9 @@ fn grant_join() -> _ {
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Meaning {
-    pub(crate) token: &'static TokenInfo,
-    pub(crate) to: Address,
-    pub(crate) value: U256,
+    pub token: &'static TokenInfo,
+    pub to: Address,
+    pub value: U256,
 }
 impl std::fmt::Display for Meaning {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -58,12 +64,15 @@ impl From<Meaning> for SpecificMeaning {
 }
 
 // A grant for token transfers, which can be scoped to specific target addresses and volume limits
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Serialize)]
 pub struct Settings {
     pub token_contract: Address,
     pub target: Option<Address>,
     pub volume_limits: Vec<VolumeRateLimit>,
 }
+impl Integrable for Settings {
+    const KIND: &'static str = "TokenTransfer";
+}
 impl From<Settings> for SpecificGrant {
     fn from(val: Settings) -> SpecificGrant {
         SpecificGrant::TokenTransfer(val)
@@ -106,13 +115,20 @@ async fn check_volume_rate_limits(
 ) -> QueryResult<Vec<EvalViolation>> {
     let mut violations = Vec::new();
 
-    let Some(longest_window) = grant.settings.volume_limits.iter().map(|l| l.window).max() else {
+    let Some(longest_window) = grant
+        .settings
+        .specific
+        .volume_limits
+        .iter()
+        .map(|l| l.window)
+        .max()
+    else {
         return Ok(violations);
     };
 
     let past_transfers = query_relevant_past_transfers(grant.id, longest_window, db).await?;
 
-    for limit in &grant.settings.volume_limits {
+    for limit in &grant.settings.specific.volume_limits {
         let window_start = chrono::Utc::now() - limit.window;
         let prospective_cumulative_volume: U256 = past_transfers
             .iter()
@@ -158,7 +174,7 @@ impl Policy for TokenTransfer {
             return Ok(violations);
         }
 
-        if let Some(allowed) = grant.settings.target
+        if let Some(allowed) = grant.settings.specific.target
             && allowed != meaning.to
         {
             violations.push(EvalViolation::InvalidTarget { target: meaning.to });
@@ -269,9 +285,11 @@ impl Policy for TokenTransfer {
 
         Ok(Some(Grant {
             id: token_grant.id,
-            shared_grant_id: token_grant.basic_grant_id,
-            shared: SharedGrantSettings::try_from_model(basic_grant)?,
-            settings,
+            common_settings_id: token_grant.basic_grant_id,
+            settings: CombinedSettings {
+                shared: SharedGrantSettings::try_from_model(basic_grant)?,
+                specific: settings,
+            },
         }))
     }
 
@@ -369,12 +387,14 @@ impl Policy for TokenTransfer {
 
                 Ok(Grant {
                     id: specific.id,
-                    shared_grant_id: specific.basic_grant_id,
-                    shared: SharedGrantSettings::try_from_model(basic)?,
-                    settings: Settings {
-                        token_contract: Address::from(token_contract),
-                        target,
-                        volume_limits,
+                    common_settings_id: specific.basic_grant_id,
+                    settings: CombinedSettings {
+                        shared: SharedGrantSettings::try_from_model(basic)?,
+                        specific: Settings {
+                            token_contract: Address::from(token_contract),
+                            target,
+                            volume_limits,
+                        },
                     },
                 })
             })
diff --git a/server/crates/arbiter-server/src/evm/policies/token_transfers/tests.rs b/server/crates/arbiter-server/src/evm/policies/token_transfers/tests.rs
index 2f1b72f..c714afc 100644
--- a/server/crates/arbiter-server/src/evm/policies/token_transfers/tests.rs
+++ b/server/crates/arbiter-server/src/evm/policies/token_transfers/tests.rs
@@ -11,7 +11,10 @@ use crate::db::{
 };
 use crate::evm::{
     abi::IERC20::transferCall,
-    policies::{EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings, VolumeRateLimit},
+    policies::{
+        CombinedSettings, EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings,
+        VolumeRateLimit,
+    },
     utils,
 };
 
@@ -134,9 +137,11 @@ async fn evaluate_rejects_nonzero_eth_value() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
-        shared: shared(),
-        settings: make_settings(None, None),
+        common_settings_id: 999,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: make_settings(None, None),
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let mut context = ctx(DAI, calldata);
@@ -163,9 +168,11 @@ async fn evaluate_passes_any_recipient_when_no_restriction() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
-        shared: shared(),
-        settings: make_settings(None, None),
+        common_settings_id: 999,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: make_settings(None, None),
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
@@ -183,9 +190,11 @@ async fn evaluate_passes_matching_restricted_recipient() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
-        shared: shared(),
-        settings: make_settings(Some(RECIPIENT), None),
+        common_settings_id: 999,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: make_settings(Some(RECIPIENT), None),
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
@@ -203,9 +212,11 @@ async fn evaluate_rejects_wrong_restricted_recipient() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
-        shared: shared(),
-        settings: make_settings(Some(RECIPIENT), None),
+        common_settings_id: 999,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: make_settings(Some(RECIPIENT), None),
+        },
     };
     let calldata = transfer_calldata(OTHER, U256::from(100u64));
     let context = ctx(DAI, calldata);
@@ -247,9 +258,11 @@ async fn evaluate_passes_volume_at_exact_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
-        shared: shared(),
-        settings,
+        common_settings_id: basic.id,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: settings,
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
@@ -290,9 +303,11 @@ async fn evaluate_rejects_volume_over_limit() {
 
     let grant = Grant {
         id: grant_id,
-        shared_grant_id: basic.id,
-        shared: shared(),
-        settings,
+        common_settings_id: basic.id,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: settings,
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(1u64));
     let context = ctx(DAI, calldata);
@@ -313,9 +328,11 @@ async fn evaluate_no_volume_limits_always_passes() {
 
     let grant = Grant {
         id: 999,
-        shared_grant_id: 999,
-        shared: shared(),
-        settings: make_settings(None, None), // no volume limits
+        common_settings_id: 999,
+        settings: CombinedSettings {
+            shared: shared(),
+            specific: make_settings(None, None), // no volume limits
+        },
     };
     let calldata = transfer_calldata(RECIPIENT, U256::from(u64::MAX));
     let context = ctx(DAI, calldata);
@@ -349,10 +366,13 @@ async fn try_find_grant_roundtrip() {
 
     assert!(found.is_some());
     let g = found.unwrap();
-    assert_eq!(g.settings.token_contract, DAI);
-    assert_eq!(g.settings.target, Some(RECIPIENT));
-    assert_eq!(g.settings.volume_limits.len(), 1);
-    assert_eq!(g.settings.volume_limits[0].max_volume, U256::from(5_000u64));
+    assert_eq!(g.settings.specific.token_contract, DAI);
+    assert_eq!(g.settings.specific.target, Some(RECIPIENT));
+    assert_eq!(g.settings.specific.volume_limits.len(), 1);
+    assert_eq!(
+        g.settings.specific.volume_limits[0].max_volume,
+        U256::from(5_000u64)
+    );
 }
 
 #[tokio::test]
@@ -434,9 +454,9 @@ async fn find_all_grants_loads_volume_limits() {
 
     let all = TokenTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 1);
-    assert_eq!(all[0].settings.volume_limits.len(), 1);
+    assert_eq!(all[0].settings.specific.volume_limits.len(), 1);
     assert_eq!(
-        all[0].settings.volume_limits[0].max_volume,
+        all[0].settings.specific.volume_limits[0].max_volume,
         U256::from(9_999u64)
     );
 }
diff --git a/server/crates/arbiter-server/src/grpc/common/outbound.rs b/server/crates/arbiter-server/src/grpc/common/outbound.rs
index 6ca8916..1b500c9 100644
--- a/server/crates/arbiter-server/src/grpc/common/outbound.rs
+++ b/server/crates/arbiter-server/src/grpc/common/outbound.rs
@@ -108,12 +108,12 @@ impl Convert for VetError {
                         violations: violations.into_iter().map(Convert::convert).collect(),
                     })
                 }
-                PolicyError::Database(_) => {
+                PolicyError::Database(_)| PolicyError::Integrity(_) => {
                     return EvmSignTransactionResult::Error(ProtoEvmError::Internal.into());
                 }
             },
         };
 
-        EvmSignTransactionResult::EvalError(ProtoTransactionEvalError { kind: Some(kind) }.into())
+        EvmSignTransactionResult::EvalError(ProtoTransactionEvalError { kind: Some(kind) })
     }
 }
diff --git a/server/crates/arbiter-server/src/grpc/user_agent/evm.rs b/server/crates/arbiter-server/src/grpc/user_agent/evm.rs
index a65b220..28725c2 100644
--- a/server/crates/arbiter-server/src/grpc/user_agent/evm.rs
+++ b/server/crates/arbiter-server/src/grpc/user_agent/evm.rs
@@ -26,8 +26,8 @@ use crate::{
     actors::user_agent::{
         UserAgentSession,
         session::connection::{
-            HandleEvmWalletCreate, HandleEvmWalletList, HandleGrantCreate, HandleGrantDelete,
-            HandleGrantList, HandleSignTransaction,
+            GrantMutationError, HandleEvmWalletCreate, HandleEvmWalletList, HandleGrantCreate,
+            HandleGrantDelete, HandleGrantList, HandleSignTransaction,
             SignTransactionError as SessionSignTransactionError,
         },
     },
@@ -114,10 +114,10 @@ async fn handle_grant_list(
             grants: grants
                 .into_iter()
                 .map(|grant| GrantEntry {
-                    id: grant.id,
-                    wallet_access_id: grant.shared.wallet_access_id,
-                    shared: Some(grant.shared.convert()),
-                    specific: Some(grant.settings.convert()),
+                    id: grant.common_settings_id,
+                    wallet_access_id: grant.settings.shared.wallet_access_id,
+                    shared: Some(grant.settings.shared.convert()),
+                    specific: Some(grant.settings.specific.convert()),
                 })
                 .collect(),
         }),
@@ -148,6 +148,9 @@ async fn handle_grant_create(
 
     let result = match actor.ask(HandleGrantCreate { basic, grant }).await {
         Ok(grant_id) => EvmGrantCreateResult::GrantId(grant_id),
+        Err(kameo::error::SendError::HandlerError(GrantMutationError::VaultSealed)) => {
+            EvmGrantCreateResult::Error(ProtoEvmError::VaultSealed.into())
+        }
         Err(err) => {
             warn!(error = ?err, "Failed to create EVM grant");
             EvmGrantCreateResult::Error(ProtoEvmError::Internal.into())
@@ -171,6 +174,9 @@ async fn handle_grant_delete(
         .await
     {
         Ok(()) => EvmGrantDeleteResult::Ok(()),
+        Err(kameo::error::SendError::HandlerError(GrantMutationError::VaultSealed)) => {
+            EvmGrantDeleteResult::Error(ProtoEvmError::VaultSealed.into())
+        }
         Err(err) => {
             warn!(error = ?err, "Failed to delete EVM grant");
             EvmGrantDeleteResult::Error(ProtoEvmError::Internal.into())
diff --git a/server/crates/arbiter-server/tests/user_agent/auth.rs b/server/crates/arbiter-server/tests/user_agent/auth.rs
index 0006343..660fae4 100644
--- a/server/crates/arbiter-server/tests/user_agent/auth.rs
+++ b/server/crates/arbiter-server/tests/user_agent/auth.rs
@@ -4,8 +4,9 @@ use arbiter_server::{
         GlobalActors,
         bootstrap::GetToken,
         keyholder::Bootstrap,
-        user_agent::{AuthPublicKey, UserAgentConnection, auth},
+        user_agent::{AuthPublicKey, UserAgentConnection, UserAgentCredentials, auth},
     },
+    crypto::integrity,
     db::{self, schema},
     safe_cell::{SafeCell, SafeCellHandle as _},
 };
@@ -20,6 +21,13 @@ use super::common::ChannelTransport;
 pub async fn test_bootstrap_token_auth() {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+    actors
+        .key_holder
+        .ask(Bootstrap {
+            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
+        })
+        .await
+        .unwrap();
     let token = actors.bootstrapper.ask(GetToken).await.unwrap().unwrap();
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
@@ -99,20 +107,39 @@ pub async fn test_bootstrap_invalid_token_auth() {
 pub async fn test_challenge_auth() {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+    actors
+        .key_holder
+        .ask(Bootstrap {
+            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
+        })
+        .await
+        .unwrap();
 
     let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
     let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
 
     {
         let mut conn = db.get().await.unwrap();
-        insert_into(schema::useragent_client::table)
+        let id: i32 = insert_into(schema::useragent_client::table)
             .values((
                 schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
                 schema::useragent_client::key_type.eq(1i32),
             ))
-            .execute(&mut conn)
+            .returning(schema::useragent_client::id)
+            .get_result(&mut conn)
             .await
             .unwrap();
+        integrity::sign_entity(
+            &mut conn,
+            &actors.key_holder,
+            &UserAgentCredentials {
+                pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
+                nonce: 1,
+            },
+            id,
+        )
+        .await
+        .unwrap();
     }
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
@@ -187,7 +214,6 @@ pub async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed()
             .values((
                 schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
                 schema::useragent_client::key_type.eq(1i32),
-                schema::useragent_client::pubkey_integrity_tag.eq(Some(vec![0u8; 32])),
             ))
             .execute(&mut conn)
             .await
@@ -211,7 +237,7 @@ pub async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed()
 
     assert!(matches!(
         task.await.unwrap(),
-        Err(auth::Error::InvalidChallengeSolution)
+        Err(auth::Error::Internal { .. })
     ));
 }
 
@@ -220,20 +246,39 @@ pub async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed()
 pub async fn test_challenge_auth_rejects_invalid_signature() {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+    actors
+        .key_holder
+        .ask(Bootstrap {
+            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
+        })
+        .await
+        .unwrap();
 
     let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
     let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
 
     {
         let mut conn = db.get().await.unwrap();
-        insert_into(schema::useragent_client::table)
+        let id: i32 = insert_into(schema::useragent_client::table)
             .values((
                 schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
                 schema::useragent_client::key_type.eq(1i32),
             ))
-            .execute(&mut conn)
+            .returning(schema::useragent_client::id)
+            .get_result(&mut conn)
             .await
             .unwrap();
+        integrity::sign_entity(
+            &mut conn,
+            &actors.key_holder,
+            &UserAgentCredentials {
+                pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
+                nonce: 1,
+            },
+            id,
+        )
+        .await
+        .unwrap();
     }
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
diff --git a/server/crates/arbiter-server/tests/user_agent/unseal.rs b/server/crates/arbiter-server/tests/user_agent/unseal.rs
index 16bb257..57cd1ee 100644
--- a/server/crates/arbiter-server/tests/user_agent/unseal.rs
+++ b/server/crates/arbiter-server/tests/user_agent/unseal.rs
@@ -151,43 +151,4 @@ pub async fn test_unseal_retry_after_invalid_key() {
         let response = user_agent.ask(encrypted_key).await;
         assert!(matches!(response, Ok(())));
     }
-}
-
-#[tokio::test]
-#[test_log::test]
-pub async fn test_unseal_backfills_missing_pubkey_integrity_tags() {
-    let seal_key = b"test-seal-key";
-    let (db, user_agent) = setup_sealed_user_agent(seal_key).await;
-
-    {
-        let mut conn = db.get().await.unwrap();
-        insert_into(arbiter_server::db::schema::useragent_client::table)
-            .values((
-                arbiter_server::db::schema::useragent_client::public_key
-                    .eq(vec![1u8, 2u8, 3u8, 4u8]),
-                arbiter_server::db::schema::useragent_client::key_type.eq(1i32),
-                arbiter_server::db::schema::useragent_client::pubkey_integrity_tag
-                    .eq(Option::<Vec<u8>>::None),
-            ))
-            .execute(&mut conn)
-            .await
-            .unwrap();
-    }
-
-    let encrypted_key = client_dh_encrypt(&user_agent, seal_key).await;
-    let response = user_agent.ask(encrypted_key).await;
-    assert!(matches!(response, Ok(())));
-
-    {
-        let mut conn = db.get().await.unwrap();
-        let tags: Vec<Option<Vec<u8>>> = arbiter_server::db::schema::useragent_client::table
-            .select(arbiter_server::db::schema::useragent_client::pubkey_integrity_tag)
-            .load(&mut conn)
-            .await
-            .unwrap();
-        assert!(
-            tags.iter()
-                .all(|tag| matches!(tag, Some(v) if v.len() == 32))
-        );
-    }
-}
+}
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