diff --git a/services/identity/src/client_service.rs b/services/identity/src/client_service.rs
index a257f6e2b..1a01a88ea 100644
--- a/services/identity/src/client_service.rs
+++ b/services/identity/src/client_service.rs
@@ -1,1177 +1,1180 @@
 // Standard library imports
 use std::str::FromStr;
 
 // External crate imports
 use comm_lib::aws::DynamoDBError;
 use comm_lib::shared::reserved_users::RESERVED_USERNAME_SET;
 use comm_opaque2::grpc::protocol_error_to_grpc_status;
 use rand::rngs::OsRng;
 use serde::{Deserialize, Serialize};
 use siwe::eip55;
 use tonic::Response;
 use tracing::{debug, error, info, warn};
 
 // Workspace crate imports
 use crate::config::CONFIG;
 use crate::constants::{
   request_metadata,
   error_types
 };
 use crate::database::{
   DBDeviceTypeInt, DatabaseClient, DeviceType, KeyPayload,
 };
 use crate::error::{DeviceListError, Error as DBError};
 use crate::grpc_services::authenticated::DeletePasswordUserInfo;
 use crate::grpc_services::protos::unauth::{
   find_user_id_request, AddReservedUsernamesRequest, AuthResponse, Empty,
   ExistingDeviceLoginRequest, FindUserIdRequest, FindUserIdResponse,
   GenerateNonceResponse, OpaqueLoginFinishRequest, OpaqueLoginStartRequest,
   OpaqueLoginStartResponse, RegistrationFinishRequest, RegistrationStartRequest,
   RegistrationStartResponse, RemoveReservedUsernameRequest,
   ReservedRegistrationStartRequest, ReservedWalletRegistrationRequest,
   SecondaryDeviceKeysUploadRequest, VerifyUserAccessTokenRequest,
   VerifyUserAccessTokenResponse, WalletAuthRequest, GetFarcasterUsersRequest,
   GetFarcasterUsersResponse
 };
 use crate::grpc_services::shared::get_value;
 use crate::grpc_utils::{
   SignedNonce, DeviceKeyUploadActions,
 };
 use crate::nonce::generate_nonce_data;
 use crate::reserved_users::{
   validate_account_ownership_message_and_get_user_id,
   validate_add_reserved_usernames_message,
   validate_remove_reserved_username_message,
 };
 use crate::siwe::{
   is_valid_ethereum_address, parse_and_verify_siwe_message, SocialProof,
 };
 use crate::token::{AccessTokenData, AuthType};
 pub use crate::grpc_services::protos::unauth::identity_client_service_server::{
     IdentityClientService, IdentityClientServiceServer,
   };
 use crate::regex::is_valid_username;
 
 #[derive(Clone, Serialize, Deserialize)]
 pub enum WorkflowInProgress {
   Registration(Box<UserRegistrationInfo>),
   Login(Box<UserLoginInfo>),
   Update(UpdateState),
   PasswordUserDeletion(Box<DeletePasswordUserInfo>),
 }
 
 #[derive(Clone, Serialize, Deserialize)]
 pub struct UserRegistrationInfo {
   pub username: String,
   pub flattened_device_key_upload: FlattenedDeviceKeyUpload,
   pub user_id: Option<String>,
   pub farcaster_id: Option<String>,
 }
 
 #[derive(Clone, Serialize, Deserialize)]
 pub struct UserLoginInfo {
   pub user_id: String,
   pub flattened_device_key_upload: FlattenedDeviceKeyUpload,
   pub opaque_server_login: comm_opaque2::server::Login,
   pub device_to_remove: Option<String>,
 }
 
 #[derive(Clone, Serialize, Deserialize)]
 pub struct UpdateState {
   pub user_id: String,
 }
 
 #[derive(Clone, Serialize, Deserialize)]
 pub struct FlattenedDeviceKeyUpload {
   pub device_id_key: String,
   pub key_payload: String,
   pub key_payload_signature: String,
   pub content_prekey: String,
   pub content_prekey_signature: String,
   pub content_one_time_keys: Vec<String>,
   pub notif_prekey: String,
   pub notif_prekey_signature: String,
   pub notif_one_time_keys: Vec<String>,
   pub device_type: DeviceType,
 }
 
 #[derive(derive_more::Constructor)]
 pub struct ClientService {
   client: DatabaseClient,
 }
 
 #[tonic::async_trait]
 impl IdentityClientService for ClientService {
   #[tracing::instrument(skip_all)]
   async fn register_password_user_start(
     &self,
     request: tonic::Request<RegistrationStartRequest>,
   ) -> Result<tonic::Response<RegistrationStartResponse>, tonic::Status> {
     let message = request.into_inner();
     debug!("Received registration request for: {}", message.username);
 
     if !is_valid_username(&message.username)
       || is_valid_ethereum_address(&message.username)
     {
       return Err(tonic::Status::invalid_argument("invalid username"));
     }
 
     self.check_username_taken(&message.username).await?;
     let username_in_reserved_usernames_table = self
       .client
       .username_in_reserved_usernames_table(&message.username)
       .await
       .map_err(handle_db_error)?;
 
     if username_in_reserved_usernames_table {
       return Err(tonic::Status::already_exists("username already exists"));
     }
 
     if RESERVED_USERNAME_SET.contains(&message.username) {
       return Err(tonic::Status::invalid_argument("username reserved"));
     }
 
     if let Some(fid) = &message.farcaster_id {
       self.check_farcaster_id_taken(fid).await?;
     }
 
     let registration_state = construct_user_registration_info(
       &message,
       None,
       message.username.clone(),
       message.farcaster_id.clone(),
     )?;
     let server_registration = comm_opaque2::server::Registration::new();
     let server_message = server_registration
       .start(
         &CONFIG.server_setup,
         &message.opaque_registration_request,
         message.username.as_bytes(),
       )
       .map_err(protocol_error_to_grpc_status)?;
     let session_id = self
       .client
       .insert_workflow(WorkflowInProgress::Registration(Box::new(
         registration_state,
       )))
       .await
       .map_err(handle_db_error)?;
 
     let response = RegistrationStartResponse {
       session_id,
       opaque_registration_response: server_message,
     };
     Ok(Response::new(response))
   }
 
   #[tracing::instrument(skip_all)]
   async fn register_reserved_password_user_start(
     &self,
     request: tonic::Request<ReservedRegistrationStartRequest>,
   ) -> Result<tonic::Response<RegistrationStartResponse>, tonic::Status> {
     let message = request.into_inner();
     self.check_username_taken(&message.username).await?;
 
     if RESERVED_USERNAME_SET.contains(&message.username) {
       return Err(tonic::Status::invalid_argument("username reserved"));
     }
 
     let username_in_reserved_usernames_table = self
       .client
       .username_in_reserved_usernames_table(&message.username)
       .await
       .map_err(handle_db_error)?;
     if !username_in_reserved_usernames_table {
       return Err(tonic::Status::permission_denied("username not reserved"));
     }
 
     let user_id = validate_account_ownership_message_and_get_user_id(
       &message.username,
       &message.keyserver_message,
       &message.keyserver_signature,
     )?;
 
     let registration_state = construct_user_registration_info(
       &message,
       Some(user_id),
       message.username.clone(),
       None,
     )?;
     let server_registration = comm_opaque2::server::Registration::new();
     let server_message = server_registration
       .start(
         &CONFIG.server_setup,
         &message.opaque_registration_request,
         message.username.as_bytes(),
       )
       .map_err(protocol_error_to_grpc_status)?;
 
     let session_id = self
       .client
       .insert_workflow(WorkflowInProgress::Registration(Box::new(
         registration_state,
       )))
       .await
       .map_err(handle_db_error)?;
 
     let response = RegistrationStartResponse {
       session_id,
       opaque_registration_response: server_message,
     };
     Ok(Response::new(response))
   }
 
   #[tracing::instrument(skip_all)]
   async fn register_password_user_finish(
     &self,
     request: tonic::Request<RegistrationFinishRequest>,
   ) -> Result<tonic::Response<AuthResponse>, tonic::Status> {
     let code_version = get_code_version(&request);
     let message = request.into_inner();
 
     if let Some(WorkflowInProgress::Registration(state)) = self
       .client
       .get_workflow(message.session_id)
       .await
       .map_err(handle_db_error)?
     {
       let server_registration = comm_opaque2::server::Registration::new();
       let password_file = server_registration
         .finish(&message.opaque_registration_upload)
         .map_err(protocol_error_to_grpc_status)?;
 
       let login_time = chrono::Utc::now();
       let device_id = state.flattened_device_key_upload.device_id_key.clone();
       let user_id = self
         .client
         .add_password_user_to_users_table(
           *state,
           password_file,
           code_version,
           login_time,
         )
         .await
         .map_err(handle_db_error)?;
 
       // Create access token
       let token = AccessTokenData::with_created_time(
         user_id.clone(),
         device_id,
         login_time,
         crate::token::AuthType::Password,
         &mut OsRng,
       );
 
       let access_token = token.access_token.clone();
 
       self
         .client
         .put_access_token_data(token)
         .await
         .map_err(handle_db_error)?;
 
       let response = AuthResponse {
         user_id,
         access_token,
       };
       Ok(Response::new(response))
     } else {
       Err(tonic::Status::not_found("session not found"))
     }
   }
 
   #[tracing::instrument(skip_all)]
   async fn log_in_password_user_start(
     &self,
     request: tonic::Request<OpaqueLoginStartRequest>,
   ) -> Result<tonic::Response<OpaqueLoginStartResponse>, tonic::Status> {
     let message = request.into_inner();
 
     debug!("Attempting to log in user: {:?}", &message.username);
     let user_id_and_password_file = self
       .client
       .get_user_id_and_password_file_from_username(&message.username)
       .await
       .map_err(handle_db_error)?;
 
     let (user_id, password_file_bytes) =
       if let Some(data) = user_id_and_password_file {
         data
       } else {
         // It's possible that the user attempting login is already registered
         // on Ashoat's keyserver. If they are, we should send back a gRPC status
         // code instructing them to get a signed message from Ashoat's keyserver
         // in order to claim their username and register with the Identity
         // service.
         let username_in_reserved_usernames_table = self
           .client
           .username_in_reserved_usernames_table(&message.username)
           .await
           .map_err(handle_db_error)?;
 
         if username_in_reserved_usernames_table {
           return Err(tonic::Status::permission_denied(
             "need keyserver message to claim username",
           ));
         }
 
         return Err(tonic::Status::not_found("user not found"));
       };
 
     let flattened_device_key_upload =
       construct_flattened_device_key_upload(&message)?;
 
     let maybe_device_to_remove = self
       .get_keyserver_device_to_remove(
         &user_id,
         &flattened_device_key_upload.device_id_key,
         message.force.unwrap_or(false),
         &flattened_device_key_upload.device_type,
       )
       .await?;
 
     let mut server_login = comm_opaque2::server::Login::new();
     let server_response = server_login
       .start(
         &CONFIG.server_setup,
         &password_file_bytes,
         &message.opaque_login_request,
         message.username.as_bytes(),
       )
       .map_err(protocol_error_to_grpc_status)?;
 
     let login_state = construct_user_login_info(
       user_id,
       server_login,
       flattened_device_key_upload,
       maybe_device_to_remove,
     )?;
 
     let session_id = self
       .client
       .insert_workflow(WorkflowInProgress::Login(Box::new(login_state)))
       .await
       .map_err(handle_db_error)?;
 
     let response = Response::new(OpaqueLoginStartResponse {
       session_id,
       opaque_login_response: server_response,
     });
     Ok(response)
   }
 
   #[tracing::instrument(skip_all)]
   async fn log_in_password_user_finish(
     &self,
     request: tonic::Request<OpaqueLoginFinishRequest>,
   ) -> Result<tonic::Response<AuthResponse>, tonic::Status> {
     let code_version = get_code_version(&request);
     let message = request.into_inner();
 
     if let Some(WorkflowInProgress::Login(state)) = self
       .client
       .get_workflow(message.session_id)
       .await
       .map_err(handle_db_error)?
     {
       let mut server_login = state.opaque_server_login.clone();
       server_login
         .finish(&message.opaque_login_upload)
         .map_err(protocol_error_to_grpc_status)?;
 
       if let Some(device_to_remove) = state.device_to_remove {
         self
           .client
           .remove_device(state.user_id.clone(), device_to_remove)
           .await
           .map_err(handle_db_error)?;
       }
 
       let login_time = chrono::Utc::now();
       self
         .client
         .add_user_device(
           state.user_id.clone(),
           state.flattened_device_key_upload.clone(),
           code_version,
           login_time,
         )
         .await
         .map_err(handle_db_error)?;
 
       // Create access token
       let token = AccessTokenData::with_created_time(
         state.user_id.clone(),
         state.flattened_device_key_upload.device_id_key,
         login_time,
         crate::token::AuthType::Password,
         &mut OsRng,
       );
 
       let access_token = token.access_token.clone();
 
       self
         .client
         .put_access_token_data(token)
         .await
         .map_err(handle_db_error)?;
 
       let response = AuthResponse {
         user_id: state.user_id,
         access_token,
       };
       Ok(Response::new(response))
     } else {
       Err(tonic::Status::not_found("session not found"))
     }
   }
 
   #[tracing::instrument(skip_all)]
   async fn log_in_wallet_user(
     &self,
     request: tonic::Request<WalletAuthRequest>,
   ) -> Result<tonic::Response<AuthResponse>, tonic::Status> {
     let code_version = get_code_version(&request);
     let message = request.into_inner();
 
     let parsed_message = parse_and_verify_siwe_message(
       &message.siwe_message,
       &message.siwe_signature,
     )?;
 
     self.verify_and_remove_nonce(&parsed_message.nonce).await?;
 
     let wallet_address = eip55(&parsed_message.address);
 
     let flattened_device_key_upload =
       construct_flattened_device_key_upload(&message)?;
 
     let login_time = chrono::Utc::now();
     let Some(user_id) = self
       .client
       .get_user_id_from_user_info(wallet_address.clone(), &AuthType::Wallet)
       .await
       .map_err(handle_db_error)?
     else {
       // It's possible that the user attempting login is already registered
       // on Ashoat's keyserver. If they are, we should send back a gRPC status
       // code instructing them to get a signed message from Ashoat's keyserver
       // in order to claim their wallet address and register with the Identity
       // service.
       let username_in_reserved_usernames_table = self
         .client
         .username_in_reserved_usernames_table(&wallet_address)
         .await
         .map_err(handle_db_error)?;
 
       if username_in_reserved_usernames_table {
         return Err(tonic::Status::permission_denied(
           "need keyserver message to claim username",
         ));
       }
 
       return Err(tonic::Status::not_found("user not found"));
     };
 
     self
       .client
       .add_user_device(
         user_id.clone(),
         flattened_device_key_upload.clone(),
         code_version,
         chrono::Utc::now(),
       )
       .await
       .map_err(handle_db_error)?;
 
     // Create access token
     let token = AccessTokenData::with_created_time(
       user_id.clone(),
       flattened_device_key_upload.device_id_key,
       login_time,
       crate::token::AuthType::Wallet,
       &mut OsRng,
     );
 
     let access_token = token.access_token.clone();
 
     self
       .client
       .put_access_token_data(token)
       .await
       .map_err(handle_db_error)?;
 
     let response = AuthResponse {
       user_id,
       access_token,
     };
     Ok(Response::new(response))
   }
 
   #[tracing::instrument(skip_all)]
   async fn register_wallet_user(
     &self,
     request: tonic::Request<WalletAuthRequest>,
   ) -> Result<tonic::Response<AuthResponse>, tonic::Status> {
     let code_version = get_code_version(&request);
     let message = request.into_inner();
 
     let parsed_message = parse_and_verify_siwe_message(
       &message.siwe_message,
       &message.siwe_signature,
     )?;
 
     match self
       .client
       .get_nonce_from_nonces_table(&parsed_message.nonce)
       .await
       .map_err(handle_db_error)?
     {
       None => return Err(tonic::Status::invalid_argument("invalid nonce")),
       Some(nonce) if nonce.is_expired() => {
         // we don't need to remove the nonce from the table here
         // because the DynamoDB TTL will take care of it
         return Err(tonic::Status::aborted("nonce expired"));
       }
       Some(_) => self
         .client
         .remove_nonce_from_nonces_table(&parsed_message.nonce)
         .await
         .map_err(handle_db_error)?,
     };
 
     let wallet_address = eip55(&parsed_message.address);
 
     self.check_wallet_address_taken(&wallet_address).await?;
     let username_in_reserved_usernames_table = self
       .client
       .username_in_reserved_usernames_table(&wallet_address)
       .await
       .map_err(handle_db_error)?;
 
     if username_in_reserved_usernames_table {
       return Err(tonic::Status::already_exists(
         "wallet address already exists",
       ));
     }
 
     if let Some(fid) = &message.farcaster_id {
       self.check_farcaster_id_taken(fid).await?;
     }
 
     let flattened_device_key_upload =
       construct_flattened_device_key_upload(&message)?;
 
     let login_time = chrono::Utc::now();
 
     let social_proof =
       SocialProof::new(message.siwe_message, message.siwe_signature);
 
     let user_id = self
       .client
       .add_wallet_user_to_users_table(
         flattened_device_key_upload.clone(),
         wallet_address,
         social_proof,
         None,
         code_version,
         login_time,
         message.farcaster_id,
       )
       .await
       .map_err(handle_db_error)?;
 
     // Create access token
     let token = AccessTokenData::with_created_time(
       user_id.clone(),
       flattened_device_key_upload.device_id_key,
       login_time,
       crate::token::AuthType::Wallet,
       &mut OsRng,
     );
 
     let access_token = token.access_token.clone();
 
     self
       .client
       .put_access_token_data(token)
       .await
       .map_err(handle_db_error)?;
 
     let response = AuthResponse {
       user_id,
       access_token,
     };
     Ok(Response::new(response))
   }
 
   #[tracing::instrument(skip_all)]
   async fn register_reserved_wallet_user(
     &self,
     request: tonic::Request<ReservedWalletRegistrationRequest>,
   ) -> Result<tonic::Response<AuthResponse>, tonic::Status> {
     let code_version = get_code_version(&request);
     let message = request.into_inner();
 
     let parsed_message = parse_and_verify_siwe_message(
       &message.siwe_message,
       &message.siwe_signature,
     )?;
 
     self.verify_and_remove_nonce(&parsed_message.nonce).await?;
 
     let wallet_address = eip55(&parsed_message.address);
 
     self.check_wallet_address_taken(&wallet_address).await?;
 
     let wallet_address_in_reserved_usernames_table = self
       .client
       .username_in_reserved_usernames_table(&wallet_address)
       .await
       .map_err(handle_db_error)?;
     if !wallet_address_in_reserved_usernames_table {
       return Err(tonic::Status::permission_denied(
         "wallet address not reserved",
       ));
     }
 
     let user_id = validate_account_ownership_message_and_get_user_id(
       &wallet_address,
       &message.keyserver_message,
       &message.keyserver_signature,
     )?;
 
     let flattened_device_key_upload =
       construct_flattened_device_key_upload(&message)?;
 
     let social_proof =
       SocialProof::new(message.siwe_message, message.siwe_signature);
 
     let login_time = chrono::Utc::now();
     self
       .client
       .add_wallet_user_to_users_table(
         flattened_device_key_upload.clone(),
         wallet_address,
         social_proof,
         Some(user_id.clone()),
         code_version,
         login_time,
         None,
       )
       .await
       .map_err(handle_db_error)?;
 
     let token = AccessTokenData::with_created_time(
       user_id.clone(),
       flattened_device_key_upload.device_id_key,
       login_time,
       crate::token::AuthType::Wallet,
       &mut OsRng,
     );
 
     let access_token = token.access_token.clone();
 
     self
       .client
       .put_access_token_data(token)
       .await
       .map_err(handle_db_error)?;
 
     let response = AuthResponse {
       user_id,
       access_token,
     };
 
     Ok(Response::new(response))
   }
 
   #[tracing::instrument(skip_all)]
   async fn upload_keys_for_registered_device_and_log_in(
     &self,
     request: tonic::Request<SecondaryDeviceKeysUploadRequest>,
   ) -> Result<tonic::Response<AuthResponse>, tonic::Status> {
     let code_version = get_code_version(&request);
     let message = request.into_inner();
 
     let challenge_response = SignedNonce::try_from(&message)?;
     let flattened_device_key_upload =
       construct_flattened_device_key_upload(&message)?;
 
     let user_id = message.user_id;
     let device_id = flattened_device_key_upload.device_id_key.clone();
 
     let nonce = challenge_response.verify_and_get_nonce(&device_id)?;
     self.verify_and_remove_nonce(&nonce).await?;
 
     let user_identifier = self
       .client
       .get_user_identifier(&user_id)
       .await
       .map_err(handle_db_error)?
       .ok_or_else(|| tonic::Status::not_found("user not found"))?;
 
     let Some(device_list) = self
       .client
       .get_current_device_list(&user_id)
       .await
       .map_err(handle_db_error)?
     else {
       warn!("User {} does not have valid device list. Secondary device auth impossible.", user_id);
       return Err(tonic::Status::aborted("device list error"));
     };
 
     if !device_list.device_ids.contains(&device_id) {
       return Err(tonic::Status::permission_denied(
         "device not in device list",
       ));
     }
 
     let login_time = chrono::Utc::now();
     let token = AccessTokenData::with_created_time(
       user_id.clone(),
       device_id,
       login_time,
       user_identifier.into(),
       &mut OsRng,
     );
     let access_token = token.access_token.clone();
     self
       .client
       .put_access_token_data(token)
       .await
       .map_err(handle_db_error)?;
 
     self
       .client
       .put_device_data(
         &user_id,
         flattened_device_key_upload,
         code_version,
         login_time,
       )
       .await
       .map_err(handle_db_error)?;
 
     let response = AuthResponse {
       user_id,
       access_token,
     };
     Ok(Response::new(response))
   }
 
   #[tracing::instrument(skip_all)]
   async fn log_in_existing_device(
     &self,
     request: tonic::Request<ExistingDeviceLoginRequest>,
   ) -> std::result::Result<tonic::Response<AuthResponse>, tonic::Status> {
     let message = request.into_inner();
     let challenge_response = SignedNonce::try_from(&message)?;
     let ExistingDeviceLoginRequest {
       user_id, device_id, ..
     } = message;
 
     let nonce = challenge_response.verify_and_get_nonce(&device_id)?;
     self.verify_and_remove_nonce(&nonce).await?;
 
     let (identifier_response, device_list_response) = tokio::join!(
       self.client.get_user_identifier(&user_id),
       self.client.get_current_device_list(&user_id)
     );
     let user_identifier = identifier_response
       .map_err(handle_db_error)?
       .ok_or_else(|| tonic::Status::not_found("user not found"))?;
 
     let device_list = device_list_response
       .map_err(handle_db_error)?
       .ok_or_else(|| {
         warn!("User {} does not have a valid device list.", user_id);
         tonic::Status::aborted("device list error")
       })?;
 
     if !device_list.device_ids.contains(&device_id) {
       return Err(tonic::Status::permission_denied(
         "device not in device list",
       ));
     }
 
     let login_time = chrono::Utc::now();
     let token = AccessTokenData::with_created_time(
       user_id.clone(),
       device_id,
       login_time,
       user_identifier.into(),
       &mut OsRng,
     );
     let access_token = token.access_token.clone();
     self
       .client
       .put_access_token_data(token)
       .await
       .map_err(handle_db_error)?;
 
     let response = AuthResponse {
       user_id,
       access_token,
     };
     Ok(Response::new(response))
   }
 
   #[tracing::instrument(skip_all)]
   async fn generate_nonce(
     &self,
     _request: tonic::Request<Empty>,
   ) -> Result<tonic::Response<GenerateNonceResponse>, tonic::Status> {
     let nonce_data = generate_nonce_data(&mut OsRng);
     match self
       .client
       .add_nonce_to_nonces_table(nonce_data.clone())
       .await
     {
       Ok(_) => Ok(Response::new(GenerateNonceResponse {
         nonce: nonce_data.nonce,
       })),
       Err(e) => Err(handle_db_error(e)),
     }
   }
 
   #[tracing::instrument(skip_all)]
   async fn verify_user_access_token(
     &self,
     request: tonic::Request<VerifyUserAccessTokenRequest>,
   ) -> Result<tonic::Response<VerifyUserAccessTokenResponse>, tonic::Status> {
     let message = request.into_inner();
     debug!("Verifying device: {}", &message.device_id);
 
     let token_valid = self
       .client
       .verify_access_token(
         message.user_id,
         message.device_id.clone(),
         message.access_token,
       )
       .await
       .map_err(handle_db_error)?;
 
     let response = Response::new(VerifyUserAccessTokenResponse { token_valid });
     debug!(
       "device {} was verified: {}",
       &message.device_id, token_valid
     );
     Ok(response)
   }
 
   #[tracing::instrument(skip_all)]
   async fn add_reserved_usernames(
     &self,
     request: tonic::Request<AddReservedUsernamesRequest>,
   ) -> Result<tonic::Response<Empty>, tonic::Status> {
     let message = request.into_inner();
 
     let user_details = validate_add_reserved_usernames_message(
       &message.message,
       &message.signature,
     )?;
 
     let filtered_user_details = self
       .client
       .filter_out_taken_usernames(user_details)
       .await
       .map_err(handle_db_error)?;
 
     self
       .client
       .add_usernames_to_reserved_usernames_table(filtered_user_details)
       .await
       .map_err(handle_db_error)?;
 
     let response = Response::new(Empty {});
     Ok(response)
   }
 
   #[tracing::instrument(skip_all)]
   async fn remove_reserved_username(
     &self,
     request: tonic::Request<RemoveReservedUsernameRequest>,
   ) -> Result<tonic::Response<Empty>, tonic::Status> {
     let message = request.into_inner();
 
     let username = validate_remove_reserved_username_message(
       &message.message,
       &message.signature,
     )?;
 
     self
       .client
       .delete_username_from_reserved_usernames_table(username)
       .await
       .map_err(handle_db_error)?;
 
     let response = Response::new(Empty {});
     Ok(response)
   }
 
   #[tracing::instrument(skip_all)]
   async fn ping(
     &self,
     _request: tonic::Request<Empty>,
   ) -> Result<Response<Empty>, tonic::Status> {
     let response = Response::new(Empty {});
     Ok(response)
   }
 
   #[tracing::instrument(skip_all)]
   async fn find_user_id(
     &self,
     request: tonic::Request<FindUserIdRequest>,
   ) -> Result<tonic::Response<FindUserIdResponse>, tonic::Status> {
     let message = request.into_inner();
 
     use find_user_id_request::Identifier;
     let (user_ident, auth_type) = match message.identifier {
       None => {
         return Err(tonic::Status::invalid_argument("no identifier provided"))
       }
       Some(Identifier::Username(username)) => (username, AuthType::Password),
       Some(Identifier::WalletAddress(address)) => (address, AuthType::Wallet),
     };
 
     let (is_reserved_result, user_id_result) = tokio::join!(
       self
         .client
         .username_in_reserved_usernames_table(&user_ident),
       self
         .client
         .get_user_id_from_user_info(user_ident.clone(), &auth_type),
     );
     let is_reserved = is_reserved_result.map_err(handle_db_error)?;
     let user_id = user_id_result.map_err(handle_db_error)?;
 
     Ok(Response::new(FindUserIdResponse {
       user_id,
       is_reserved,
     }))
   }
 
   #[tracing::instrument(skip_all)]
   async fn get_farcaster_users(
     &self,
     request: tonic::Request<GetFarcasterUsersRequest>,
   ) -> Result<tonic::Response<GetFarcasterUsersResponse>, tonic::Status> {
     let message = request.into_inner();
 
     let farcaster_users = self
       .client
       .get_farcaster_users(message.farcaster_ids)
       .await
       .map_err(handle_db_error)?
       .into_iter()
       .map(|d| d.0)
       .collect();
 
     Ok(Response::new(GetFarcasterUsersResponse { farcaster_users }))
   }
 }
 
 impl ClientService {
   async fn check_username_taken(
     &self,
     username: &str,
   ) -> Result<(), tonic::Status> {
     let username_taken = self
       .client
       .username_taken(username.to_string())
       .await
       .map_err(handle_db_error)?;
     if username_taken {
       return Err(tonic::Status::already_exists("username already exists"));
     }
     Ok(())
   }
 
   async fn check_wallet_address_taken(
     &self,
     wallet_address: &str,
   ) -> Result<(), tonic::Status> {
     let wallet_address_taken = self
       .client
       .wallet_address_taken(wallet_address.to_string())
       .await
       .map_err(handle_db_error)?;
     if wallet_address_taken {
       return Err(tonic::Status::already_exists(
         "wallet address already exists",
       ));
     }
     Ok(())
   }
 
   async fn check_farcaster_id_taken(
     &self,
     farcaster_id: &str,
   ) -> Result<(), tonic::Status> {
     let fid_already_registered = !self
       .client
       .get_farcaster_users(vec![farcaster_id.to_string()])
       .await
       .map_err(handle_db_error)?
       .is_empty();
     if fid_already_registered {
       return Err(tonic::Status::already_exists(
         "farcaster ID already associated with different user",
       ));
     }
     Ok(())
   }
 
   async fn verify_and_remove_nonce(
     &self,
     nonce: &str,
   ) -> Result<(), tonic::Status> {
     match self
       .client
       .get_nonce_from_nonces_table(nonce)
       .await
       .map_err(handle_db_error)?
     {
       None => return Err(tonic::Status::invalid_argument("invalid nonce")),
       Some(nonce) if nonce.is_expired() => {
         // we don't need to remove the nonce from the table here
         // because the DynamoDB TTL will take care of it
         return Err(tonic::Status::aborted("nonce expired"));
       }
       Some(nonce_data) => self
         .client
         .remove_nonce_from_nonces_table(&nonce_data.nonce)
         .await
         .map_err(handle_db_error)?,
     };
     Ok(())
   }
 
   async fn get_keyserver_device_to_remove(
     &self,
     user_id: &str,
     new_keyserver_device_id: &str,
     force: bool,
     device_type: &DeviceType,
   ) -> Result<Option<String>, tonic::Status> {
     if device_type != &DeviceType::Keyserver {
       return Ok(None);
     }
 
     let maybe_keyserver_device_id = self
       .client
       .get_keyserver_device_id_for_user(user_id)
       .await
       .map_err(handle_db_error)?;
 
     let Some(existing_keyserver_device_id) = maybe_keyserver_device_id else {
       return Ok(None);
     };
 
     if new_keyserver_device_id == existing_keyserver_device_id {
       return Ok(None);
     }
 
     if force {
       info!(
         "keyserver {} will be removed from the device list",
         existing_keyserver_device_id
       );
       Ok(Some(existing_keyserver_device_id))
     } else {
       Err(tonic::Status::already_exists(
         "user already has a keyserver",
       ))
     }
   }
 }
 
 #[tracing::instrument(skip_all)]
 pub fn handle_db_error(db_error: DBError) -> tonic::Status {
   match db_error {
     DBError::AwsSdk(DynamoDBError::InternalServerError(_))
     | DBError::AwsSdk(DynamoDBError::ProvisionedThroughputExceededException(
       _,
     ))
     | DBError::AwsSdk(DynamoDBError::RequestLimitExceeded(_)) => {
       tonic::Status::unavailable("please retry")
     }
     DBError::DeviceList(DeviceListError::InvalidDeviceListUpdate) => {
       tonic::Status::invalid_argument("invalid device list update")
     }
+    DBError::DeviceList(DeviceListError::InvalidSignature) => {
+      tonic::Status::invalid_argument("invalid device list signature")
+    }
     e => {
       error!(
         errorType = error_types::GENERIC_DB_LOG,
         "Encountered an unexpected error: {}", e
       );
       tonic::Status::failed_precondition("unexpected error")
     }
   }
 }
 
 fn construct_user_registration_info(
   message: &impl DeviceKeyUploadActions,
   user_id: Option<String>,
   username: String,
   farcaster_id: Option<String>,
 ) -> Result<UserRegistrationInfo, tonic::Status> {
   Ok(UserRegistrationInfo {
     username,
     flattened_device_key_upload: construct_flattened_device_key_upload(
       message,
     )?,
     user_id,
     farcaster_id,
   })
 }
 
 fn construct_user_login_info(
   user_id: String,
   opaque_server_login: comm_opaque2::server::Login,
   flattened_device_key_upload: FlattenedDeviceKeyUpload,
   device_to_remove: Option<String>,
 ) -> Result<UserLoginInfo, tonic::Status> {
   Ok(UserLoginInfo {
     user_id,
     flattened_device_key_upload,
     opaque_server_login,
     device_to_remove,
   })
 }
 
 fn construct_flattened_device_key_upload(
   message: &impl DeviceKeyUploadActions,
 ) -> Result<FlattenedDeviceKeyUpload, tonic::Status> {
   let key_info = KeyPayload::from_str(&message.payload()?)
     .map_err(|_| tonic::Status::invalid_argument("malformed payload"))?;
 
   let flattened_device_key_upload = FlattenedDeviceKeyUpload {
     device_id_key: key_info.primary_identity_public_keys.ed25519,
     key_payload: message.payload()?,
     key_payload_signature: message.payload_signature()?,
     content_prekey: message.content_prekey()?,
     content_prekey_signature: message.content_prekey_signature()?,
     content_one_time_keys: message.one_time_content_prekeys()?,
     notif_prekey: message.notif_prekey()?,
     notif_prekey_signature: message.notif_prekey_signature()?,
     notif_one_time_keys: message.one_time_notif_prekeys()?,
     device_type: DeviceType::try_from(DBDeviceTypeInt(message.device_type()?))
       .map_err(handle_db_error)?,
   };
 
   Ok(flattened_device_key_upload)
 }
 
 fn get_code_version<T: std::fmt::Debug>(req: &tonic::Request<T>) -> u64 {
   get_value(req, request_metadata::CODE_VERSION)
     .and_then(|version| version.parse().ok())
     .unwrap_or_else(|| {
       warn!(
         "Could not retrieve code version from request: {:?}. Defaulting to 0",
         req
       );
       Default::default()
     })
 }
diff --git a/services/identity/src/database/device_list.rs b/services/identity/src/database/device_list.rs
index 3bbbb6899..0d3b3b801 100644
--- a/services/identity/src/database/device_list.rs
+++ b/services/identity/src/database/device_list.rs
@@ -1,1558 +1,1565 @@
 use std::collections::HashMap;
 
 use chrono::{DateTime, Utc};
 use comm_lib::{
   aws::ddb::{
     operation::{get_item::GetItemOutput, query::builders::QueryFluentBuilder},
     types::{
       error::TransactionCanceledException, AttributeValue, Delete,
       DeleteRequest, Put, TransactWriteItem, Update, WriteRequest,
     },
   },
   database::{
     AttributeExtractor, AttributeMap, DBItemAttributeError, DBItemError,
     DynamoDBError, TryFromAttribute,
   },
 };
 use tracing::{debug, error, warn};
 
 use crate::{
   client_service::FlattenedDeviceKeyUpload,
   constants::{
     devices_table::{self, *},
     error_types, USERS_TABLE, USERS_TABLE_DEVICELIST_TIMESTAMP_ATTRIBUTE_NAME,
     USERS_TABLE_PARTITION_KEY,
   },
   error::{DeviceListError, Error},
   grpc_services::protos::{self, unauth::DeviceType},
   grpc_utils::DeviceKeysInfo,
   olm::is_valid_olm_key,
 };
 
 use super::DatabaseClient;
 
 // We omit the content and notif one-time key count attributes from this struct
 // because they are internal helpers and are not provided by users
 #[derive(Clone, Debug)]
 pub struct DeviceRow {
   pub user_id: String,
   pub device_id: String,
   pub device_type: DeviceType,
   pub device_key_info: IdentityKeyInfo,
   pub content_prekey: Prekey,
   pub notif_prekey: Prekey,
 
   // migration-related data
   pub code_version: u64,
   /// Timestamp of last login (access token generation)
   pub login_time: DateTime<Utc>,
 }
 
 #[derive(Clone, Debug)]
 pub struct DeviceListRow {
   pub user_id: String,
   pub timestamp: DateTime<Utc>,
   pub device_ids: Vec<String>,
   /// Primary device signature. This is `None` for Identity-generated lists.
   pub current_primary_signature: Option<String>,
   /// Last primary device signature, in case the primary device has changed
   /// since last device list update.
   pub last_primary_signature: Option<String>,
 }
 
 #[derive(Clone, Debug)]
 pub struct IdentityKeyInfo {
   pub key_payload: String,
   pub key_payload_signature: String,
 }
 
 #[derive(Clone, Debug)]
 pub struct Prekey {
   pub prekey: String,
   pub prekey_signature: String,
 }
 
 /// A struct representing device list update payload
 /// issued by the primary device.
 /// For the JSON payload, see [`crate::device_list::SignedDeviceList`]
 pub struct DeviceListUpdate {
   pub devices: Vec<String>,
   pub timestamp: DateTime<Utc>,
   /// Primary device signature. This is `None` for Identity-generated lists.
   pub current_primary_signature: Option<String>,
   /// Last primary device signature, in case the primary device has changed
   /// since last device list update.
   pub last_primary_signature: Option<String>,
+  /// Raw update payload to verify signatures
+  pub raw_payload: String,
 }
 
 impl DeviceRow {
   #[tracing::instrument(skip_all)]
   pub fn from_device_key_upload(
     user_id: impl Into<String>,
     upload: FlattenedDeviceKeyUpload,
     code_version: u64,
     login_time: DateTime<Utc>,
   ) -> Result<Self, Error> {
     if !is_valid_olm_key(&upload.content_prekey)
       || !is_valid_olm_key(&upload.notif_prekey)
     {
       error!(
         errorType = error_types::DEVICE_LIST_DB_LOG,
         "Invalid prekey format"
       );
       return Err(Error::InvalidFormat);
     }
     let device_row = Self {
       user_id: user_id.into(),
       device_id: upload.device_id_key,
       device_type: DeviceType::from_str_name(upload.device_type.as_str_name())
         .expect("DeviceType conversion failed. Identity client and server protos mismatch"),
       device_key_info: IdentityKeyInfo {
         key_payload: upload.key_payload,
         key_payload_signature: upload.key_payload_signature,
       },
       content_prekey: Prekey {
         prekey: upload.content_prekey,
         prekey_signature: upload.content_prekey_signature,
       },
       notif_prekey: Prekey {
         prekey: upload.notif_prekey,
         prekey_signature: upload.notif_prekey_signature,
       },
       code_version,
       login_time,
     };
     Ok(device_row)
   }
 }
 
 impl DeviceListRow {
   /// Generates new device list row from given devices.
   /// Used only for Identity-generated (unsigned) device lists.
   fn new(
     user_id: impl Into<String>,
     device_ids: Vec<String>,
     update_info: &UpdateOperationInfo,
   ) -> Self {
     Self {
       user_id: user_id.into(),
       device_ids,
       timestamp: update_info.timestamp.unwrap_or_else(Utc::now),
       current_primary_signature: update_info.current_signature.clone(),
       last_primary_signature: update_info.last_signature.clone(),
     }
   }
 }
 
 // helper structs for converting to/from attribute values for sort key (a.k.a itemID)
 pub struct DeviceIDAttribute(pub String);
 struct DeviceListKeyAttribute(DateTime<Utc>);
 
 impl From<DeviceIDAttribute> for AttributeValue {
   fn from(value: DeviceIDAttribute) -> Self {
     AttributeValue::S(format!("{DEVICE_ITEM_KEY_PREFIX}{}", value.0))
   }
 }
 
 impl From<DeviceListKeyAttribute> for AttributeValue {
   fn from(value: DeviceListKeyAttribute) -> Self {
     AttributeValue::S(format!(
       "{DEVICE_LIST_KEY_PREFIX}{}",
       value.0.to_rfc3339()
     ))
   }
 }
 
 impl TryFrom<Option<AttributeValue>> for DeviceIDAttribute {
   type Error = DBItemError;
   fn try_from(value: Option<AttributeValue>) -> Result<Self, Self::Error> {
     let item_id = String::try_from_attr(ATTR_ITEM_ID, value)?;
 
     // remove the device- prefix
     let device_id = item_id
       .strip_prefix(DEVICE_ITEM_KEY_PREFIX)
       .ok_or_else(|| DBItemError {
         attribute_name: ATTR_ITEM_ID.to_string(),
         attribute_value: item_id.clone().into(),
         attribute_error: DBItemAttributeError::InvalidValue,
       })?
       .to_string();
 
     Ok(Self(device_id))
   }
 }
 
 impl TryFrom<Option<AttributeValue>> for DeviceListKeyAttribute {
   type Error = DBItemError;
   fn try_from(value: Option<AttributeValue>) -> Result<Self, Self::Error> {
     let item_id = String::try_from_attr(ATTR_ITEM_ID, value)?;
 
     // remove the device-list- prefix, then parse the timestamp
     let timestamp: DateTime<Utc> = item_id
       .strip_prefix(DEVICE_LIST_KEY_PREFIX)
       .ok_or_else(|| DBItemError {
         attribute_name: ATTR_ITEM_ID.to_string(),
         attribute_value: item_id.clone().into(),
         attribute_error: DBItemAttributeError::InvalidValue,
       })
       .and_then(|s| {
         s.parse().map_err(|e| {
           DBItemError::new(
             ATTR_ITEM_ID.to_string(),
             item_id.clone().into(),
             DBItemAttributeError::InvalidTimestamp(e),
           )
         })
       })?;
 
     Ok(Self(timestamp))
   }
 }
 
 impl TryFrom<AttributeMap> for DeviceRow {
   type Error = DBItemError;
 
   fn try_from(mut attrs: AttributeMap) -> Result<Self, Self::Error> {
     let user_id = attrs.take_attr(ATTR_USER_ID)?;
     let DeviceIDAttribute(device_id) = attrs.remove(ATTR_ITEM_ID).try_into()?;
 
     let raw_device_type: String = attrs.take_attr(ATTR_DEVICE_TYPE)?;
     let device_type =
       DeviceType::from_str_name(&raw_device_type).ok_or_else(|| {
         DBItemError::new(
           ATTR_DEVICE_TYPE.to_string(),
           raw_device_type.into(),
           DBItemAttributeError::InvalidValue,
         )
       })?;
 
     let device_key_info = attrs
       .take_attr::<AttributeMap>(ATTR_DEVICE_KEY_INFO)
       .and_then(IdentityKeyInfo::try_from)?;
 
     let content_prekey = attrs
       .take_attr::<AttributeMap>(ATTR_CONTENT_PREKEY)
       .and_then(Prekey::try_from)?;
 
     let notif_prekey = attrs
       .take_attr::<AttributeMap>(ATTR_NOTIF_PREKEY)
       .and_then(Prekey::try_from)?;
 
     let code_version = attrs
       .remove(ATTR_CODE_VERSION)
       .and_then(|attr| attr.as_n().ok().cloned())
       .and_then(|val| val.parse::<u64>().ok())
       .unwrap_or_default();
 
     let login_time: DateTime<Utc> = attrs.take_attr(ATTR_LOGIN_TIME)?;
 
     Ok(Self {
       user_id,
       device_id,
       device_type,
       device_key_info,
       content_prekey,
       notif_prekey,
       code_version,
       login_time,
     })
   }
 }
 
 impl From<DeviceRow> for AttributeMap {
   fn from(value: DeviceRow) -> Self {
     HashMap::from([
       (ATTR_USER_ID.to_string(), AttributeValue::S(value.user_id)),
       (
         ATTR_ITEM_ID.to_string(),
         DeviceIDAttribute(value.device_id).into(),
       ),
       (
         ATTR_DEVICE_TYPE.to_string(),
         AttributeValue::S(value.device_type.as_str_name().to_string()),
       ),
       (
         ATTR_DEVICE_KEY_INFO.to_string(),
         value.device_key_info.into(),
       ),
       (ATTR_CONTENT_PREKEY.to_string(), value.content_prekey.into()),
       (ATTR_NOTIF_PREKEY.to_string(), value.notif_prekey.into()),
       // migration attributes
       (
         ATTR_CODE_VERSION.to_string(),
         AttributeValue::N(value.code_version.to_string()),
       ),
       (
         ATTR_LOGIN_TIME.to_string(),
         AttributeValue::S(value.login_time.to_rfc3339()),
       ),
     ])
   }
 }
 
 impl From<IdentityKeyInfo> for protos::unauth::IdentityKeyInfo {
   fn from(value: IdentityKeyInfo) -> Self {
     Self {
       payload: value.key_payload,
       payload_signature: value.key_payload_signature,
     }
   }
 }
 
 impl From<IdentityKeyInfo> for AttributeValue {
   fn from(value: IdentityKeyInfo) -> Self {
     let attrs = HashMap::from([
       (
         ATTR_KEY_PAYLOAD.to_string(),
         AttributeValue::S(value.key_payload),
       ),
       (
         ATTR_KEY_PAYLOAD_SIGNATURE.to_string(),
         AttributeValue::S(value.key_payload_signature),
       ),
     ]);
     AttributeValue::M(attrs)
   }
 }
 
 impl TryFrom<AttributeMap> for IdentityKeyInfo {
   type Error = DBItemError;
   fn try_from(mut attrs: AttributeMap) -> Result<Self, Self::Error> {
     let key_payload = attrs.take_attr(ATTR_KEY_PAYLOAD)?;
     let key_payload_signature = attrs.take_attr(ATTR_KEY_PAYLOAD_SIGNATURE)?;
 
     Ok(Self {
       key_payload,
       key_payload_signature,
     })
   }
 }
 
 impl From<Prekey> for AttributeValue {
   fn from(value: Prekey) -> Self {
     let attrs = HashMap::from([
       (ATTR_PREKEY.to_string(), AttributeValue::S(value.prekey)),
       (
         ATTR_PREKEY_SIGNATURE.to_string(),
         AttributeValue::S(value.prekey_signature),
       ),
     ]);
     AttributeValue::M(attrs)
   }
 }
 
 impl From<Prekey> for protos::unauth::Prekey {
   fn from(value: Prekey) -> Self {
     Self {
       prekey: value.prekey,
       prekey_signature: value.prekey_signature,
     }
   }
 }
 
 impl From<protos::unauth::Prekey> for Prekey {
   fn from(value: protos::unauth::Prekey) -> Self {
     Self {
       prekey: value.prekey,
       prekey_signature: value.prekey_signature,
     }
   }
 }
 
 impl TryFrom<AttributeMap> for Prekey {
   type Error = DBItemError;
   fn try_from(mut attrs: AttributeMap) -> Result<Self, Self::Error> {
     let prekey = attrs.take_attr(ATTR_PREKEY)?;
     let prekey_signature = attrs.take_attr(ATTR_PREKEY_SIGNATURE)?;
     Ok(Self {
       prekey,
       prekey_signature,
     })
   }
 }
 
 impl TryFrom<AttributeMap> for DeviceListRow {
   type Error = DBItemError;
 
   fn try_from(mut attrs: AttributeMap) -> Result<Self, Self::Error> {
     let user_id = attrs.take_attr(ATTR_USER_ID)?;
     let DeviceListKeyAttribute(timestamp) =
       attrs.remove(ATTR_ITEM_ID).try_into()?;
 
     // validate timestamps are in sync
     let timestamps_match = attrs
       .remove(ATTR_TIMESTAMP)
       .and_then(|attr| attr.as_n().ok().cloned())
       .and_then(|val| val.parse::<i64>().ok())
       .filter(|val| *val == timestamp.timestamp_millis())
       .is_some();
     if !timestamps_match {
       warn!(
         "DeviceList timestamp mismatch for (userID={}, itemID={})",
         &user_id,
         timestamp.to_rfc3339()
       );
     }
 
     let device_ids: Vec<String> = attrs.take_attr(ATTR_DEVICE_IDS)?;
 
     let current_primary_signature = attrs.take_attr(ATTR_CURRENT_SIGNATURE)?;
     let last_primary_signature = attrs.take_attr(ATTR_LAST_SIGNATURE)?;
 
     Ok(Self {
       user_id,
       timestamp,
       device_ids,
       current_primary_signature,
       last_primary_signature,
     })
   }
 }
 
 impl From<DeviceListRow> for AttributeMap {
   fn from(device_list: DeviceListRow) -> Self {
     let mut attrs = HashMap::new();
     attrs.insert(
       ATTR_USER_ID.to_string(),
       AttributeValue::S(device_list.user_id.clone()),
     );
     attrs.insert(
       ATTR_ITEM_ID.to_string(),
       DeviceListKeyAttribute(device_list.timestamp).into(),
     );
     attrs.insert(
       ATTR_TIMESTAMP.to_string(),
       AttributeValue::N(device_list.timestamp.timestamp_millis().to_string()),
     );
     attrs.insert(
       ATTR_DEVICE_IDS.to_string(),
       AttributeValue::L(
         device_list
           .device_ids
           .into_iter()
           .map(AttributeValue::S)
           .collect(),
       ),
     );
     if let Some(current_signature) = device_list.current_primary_signature {
       attrs.insert(
         ATTR_CURRENT_SIGNATURE.to_string(),
         AttributeValue::S(current_signature),
       );
     }
     if let Some(last_signature) = device_list.last_primary_signature {
       attrs.insert(
         ATTR_CURRENT_SIGNATURE.to_string(),
         AttributeValue::S(last_signature),
       );
     }
     attrs
   }
 }
 
 impl DatabaseClient {
   /// Retrieves user's current devices and their full data
   #[tracing::instrument(skip_all)]
   pub async fn get_current_devices(
     &self,
     user_id: impl Into<String>,
   ) -> Result<Vec<DeviceRow>, Error> {
     let response =
       query_rows_with_prefix(self, user_id, DEVICE_ITEM_KEY_PREFIX)
         .send()
         .await
         .map_err(|e| {
           error!(
             errorType = error_types::DEVICE_LIST_DB_LOG,
             "Failed to get current devices: {:?}", e
           );
           Error::AwsSdk(e.into())
         })?;
 
     let Some(rows) = response.items else {
       return Ok(Vec::new());
     };
 
     rows
       .into_iter()
       .map(DeviceRow::try_from)
       .collect::<Result<Vec<DeviceRow>, DBItemError>>()
       .map_err(Error::from)
   }
 
   /// Gets user's device list history
   #[tracing::instrument(skip_all)]
   pub async fn get_device_list_history(
     &self,
     user_id: impl Into<String>,
     since: Option<DateTime<Utc>>,
   ) -> Result<Vec<DeviceListRow>, Error> {
     let rows = if let Some(since) = since {
       // When timestamp is provided, it's better to query device lists by timestamp LSI
       self
         .client
         .query()
         .table_name(devices_table::NAME)
         .index_name(devices_table::TIMESTAMP_INDEX_NAME)
         .consistent_read(true)
         .key_condition_expression("#user_id = :user_id AND #timestamp > :since")
         .expression_attribute_names("#user_id", ATTR_USER_ID)
         .expression_attribute_names("#timestamp", ATTR_TIMESTAMP)
         .expression_attribute_values(
           ":user_id",
           AttributeValue::S(user_id.into()),
         )
         .expression_attribute_values(
           ":since",
           AttributeValue::N(since.timestamp_millis().to_string()),
         )
         .send()
         .await
         .map_err(|e| {
           error!(
             errorType = error_types::DEVICE_LIST_DB_LOG,
             "Failed to query device list updates by index: {:?}", e
           );
           Error::AwsSdk(e.into())
         })?
         .items
     } else {
       // Query all device lists for user
       query_rows_with_prefix(self, user_id, DEVICE_LIST_KEY_PREFIX)
         .send()
         .await
         .map_err(|e| {
           error!(
             errorType = error_types::DEVICE_LIST_DB_LOG,
             "Failed to query device list updates (all): {:?}", e
           );
           Error::AwsSdk(e.into())
         })?
         .items
     };
 
     rows
       .unwrap_or_default()
       .into_iter()
       .map(DeviceListRow::try_from)
       .collect::<Result<Vec<DeviceListRow>, DBItemError>>()
       .map_err(Error::from)
   }
 
   /// Returns all devices' keys for the given user. Response is in the same format
   /// as [DatabaseClient::get_keys_for_user] for compatibility reasons.
   #[tracing::instrument(skip_all)]
   pub async fn get_keys_for_user_devices(
     &self,
     user_id: impl Into<String>,
   ) -> Result<super::Devices, Error> {
     let user_devices = self.get_current_devices(user_id).await?;
     let user_devices_keys = user_devices
       .into_iter()
       .map(|device| (device.device_id.clone(), DeviceKeysInfo::from(device)))
       .collect();
     Ok(user_devices_keys)
   }
 
   #[tracing::instrument(skip_all)]
   pub async fn update_device_prekeys(
     &self,
     user_id: impl Into<String>,
     device_id: impl Into<String>,
     content_prekey: Prekey,
     notif_prekey: Prekey,
   ) -> Result<(), Error> {
     if !is_valid_olm_key(&content_prekey.prekey)
       || !is_valid_olm_key(&notif_prekey.prekey)
     {
       error!(
         errorType = error_types::DEVICE_LIST_DB_LOG,
         "Invalid prekey format"
       );
       return Err(Error::InvalidFormat);
     }
     self
       .client
       .update_item()
       .table_name(devices_table::NAME)
       .key(ATTR_USER_ID, AttributeValue::S(user_id.into()))
       .key(ATTR_ITEM_ID, DeviceIDAttribute(device_id.into()).into())
       .condition_expression(
         "attribute_exists(#user_id) AND attribute_exists(#item_id)",
       )
       .update_expression(
         "SET #content_prekey = :content_prekey, #notif_prekey = :notif_prekey",
       )
       .expression_attribute_names("#user_id", ATTR_USER_ID)
       .expression_attribute_names("#item_id", ATTR_ITEM_ID)
       .expression_attribute_names("#content_prekey", ATTR_CONTENT_PREKEY)
       .expression_attribute_names("#notif_prekey", ATTR_NOTIF_PREKEY)
       .expression_attribute_values(":content_prekey", content_prekey.into())
       .expression_attribute_values(":notif_prekey", notif_prekey.into())
       .send()
       .await
       .map_err(|e| {
         error!(
           errorType = error_types::DEVICE_LIST_DB_LOG,
           "Failed to update device prekeys: {:?}", e
         );
         Error::AwsSdk(e.into())
       })?;
 
     Ok(())
   }
 
   /// Checks if given device exists on user's current device list
   #[tracing::instrument(skip_all)]
   pub async fn device_exists(
     &self,
     user_id: impl Into<String>,
     device_id: impl Into<String>,
   ) -> Result<bool, Error> {
     let GetItemOutput { item, .. } = self
       .client
       .get_item()
       .table_name(devices_table::NAME)
       .key(ATTR_USER_ID, AttributeValue::S(user_id.into()))
       .key(ATTR_ITEM_ID, DeviceIDAttribute(device_id.into()).into())
       // only fetch the primary key, we don't need the rest
       .projection_expression(format!("{ATTR_USER_ID}, {ATTR_ITEM_ID}"))
       .send()
       .await
       .map_err(|e| {
         error!(
           errorType = error_types::DEVICE_LIST_DB_LOG,
           "Failed to check if device exists: {:?}", e
         );
         Error::AwsSdk(e.into())
       })?;
 
     Ok(item.is_some())
   }
 
   #[tracing::instrument(skip_all)]
   pub async fn get_device_data(
     &self,
     user_id: impl Into<String>,
     device_id: impl Into<String>,
   ) -> Result<Option<DeviceRow>, Error> {
     let GetItemOutput { item, .. } = self
       .client
       .get_item()
       .table_name(devices_table::NAME)
       .key(ATTR_USER_ID, AttributeValue::S(user_id.into()))
       .key(ATTR_ITEM_ID, DeviceIDAttribute(device_id.into()).into())
       .send()
       .await
       .map_err(|e| {
         error!(
           errorType = error_types::DEVICE_LIST_DB_LOG,
           "Failed to fetch device data: {:?}", e
         );
         Error::AwsSdk(e.into())
       })?;
 
     let Some(attrs) = item else {
       return Ok(None);
     };
 
     let device_data = DeviceRow::try_from(attrs)?;
     Ok(Some(device_data))
   }
 
   /// Fails if the device list is empty
   #[tracing::instrument(skip_all)]
   pub async fn get_primary_device_data(
     &self,
     user_id: &str,
   ) -> Result<DeviceRow, Error> {
     let device_list = self.get_current_device_list(user_id).await?;
     let Some(primary_device_id) = device_list
       .as_ref()
       .and_then(|list| list.device_ids.first())
     else {
       error!(
         user_id,
         errorType = error_types::DEVICE_LIST_DB_LOG,
         "Device list is empty. Cannot fetch primary device"
       );
       return Err(Error::DeviceList(DeviceListError::DeviceNotFound));
     };
 
     self
       .get_device_data(user_id, primary_device_id)
       .await?
       .ok_or_else(|| {
         error!(
           errorType = error_types::DEVICE_LIST_DB_LOG,
           "Corrupt database. Missing primary device data for user {}", user_id
         );
         Error::MissingItem
       })
   }
 
   /// Required only for migration purposes (determining primary device)
   #[tracing::instrument(skip_all)]
   pub async fn update_device_login_time(
     &self,
     user_id: impl Into<String>,
     device_id: impl Into<String>,
     login_time: DateTime<Utc>,
   ) -> Result<(), Error> {
     self
       .client
       .update_item()
       .table_name(devices_table::NAME)
       .key(ATTR_USER_ID, AttributeValue::S(user_id.into()))
       .key(ATTR_ITEM_ID, DeviceIDAttribute(device_id.into()).into())
       .condition_expression(
         "attribute_exists(#user_id) AND attribute_exists(#item_id)",
       )
       .update_expression("SET #login_time = :login_time")
       .expression_attribute_names("#user_id", ATTR_USER_ID)
       .expression_attribute_names("#item_id", ATTR_ITEM_ID)
       .expression_attribute_names("#login_time", ATTR_LOGIN_TIME)
       .expression_attribute_values(
         ":login_time",
         AttributeValue::S(login_time.to_rfc3339()),
       )
       .send()
       .await
       .map_err(|e| {
         error!(
           errorType = error_types::DEVICE_LIST_DB_LOG,
           "Failed to update device login time: {:?}", e
         );
         Error::AwsSdk(e.into())
       })?;
 
     Ok(())
   }
 
   #[tracing::instrument(skip_all)]
   pub async fn get_current_device_list(
     &self,
     user_id: impl Into<String>,
   ) -> Result<Option<DeviceListRow>, Error> {
     self
       .client
       .query()
       .table_name(devices_table::NAME)
       .index_name(devices_table::TIMESTAMP_INDEX_NAME)
       .consistent_read(true)
       .key_condition_expression("#user_id = :user_id")
       // sort descending
       .scan_index_forward(false)
       .expression_attribute_names("#user_id", ATTR_USER_ID)
       .expression_attribute_values(
         ":user_id",
         AttributeValue::S(user_id.into()),
       )
       .limit(1)
       .send()
       .await
       .map_err(|e| {
         error!(
           errorType = error_types::DEVICE_LIST_DB_LOG,
           "Failed to query device list updates by index: {:?}", e
         );
         Error::AwsSdk(e.into())
       })?
       .items
       .and_then(|mut items| items.pop())
       .map(DeviceListRow::try_from)
       .transpose()
       .map_err(Error::from)
   }
 
   /// Adds device data to devices table. If the device already exists, its
   /// data is overwritten. This does not update the device list; the device ID
   /// should already be present in the device list.
   #[tracing::instrument(skip_all)]
   pub async fn put_device_data(
     &self,
     user_id: impl Into<String>,
     device_key_upload: FlattenedDeviceKeyUpload,
     code_version: u64,
     login_time: DateTime<Utc>,
   ) -> Result<(), Error> {
     let content_one_time_keys = device_key_upload.content_one_time_keys.clone();
     let notif_one_time_keys = device_key_upload.notif_one_time_keys.clone();
     let user_id_string = user_id.into();
     let new_device = DeviceRow::from_device_key_upload(
       user_id_string.clone(),
       device_key_upload,
       code_version,
       login_time,
     )?;
     let device_id = new_device.device_id.clone();
 
     self
       .client
       .put_item()
       .table_name(devices_table::NAME)
       .set_item(Some(new_device.into()))
       .send()
       .await
       .map_err(|e| {
         error!(
           errorType = error_types::DEVICE_LIST_DB_LOG,
           "Failed to put device data: {:?}", e
         );
         Error::AwsSdk(e.into())
       })?;
 
     self
       .append_one_time_prekeys(
         &user_id_string,
         &device_id,
         &content_one_time_keys,
         &notif_one_time_keys,
       )
       .await?;
 
     Ok(())
   }
 
   /// Adds new device to user's device list. If the device already exists, the
   /// operation fails. Transactionally generates new device list version.
   pub async fn add_device(
     &self,
     user_id: impl Into<String>,
     device_key_upload: FlattenedDeviceKeyUpload,
     code_version: u64,
     login_time: DateTime<Utc>,
   ) -> Result<(), Error> {
     let user_id: String = user_id.into();
     self
       .transact_update_devicelist(&user_id, |device_ids, mut devices_data| {
         let new_device = DeviceRow::from_device_key_upload(
           &user_id,
           device_key_upload,
           code_version,
           login_time,
         )?;
 
         if device_ids.iter().any(|id| &new_device.device_id == id) {
           warn!(
             "Device already exists in user's device list \
               (userID={}, deviceID={})",
             &user_id, &new_device.device_id
           );
           return Err(Error::DeviceList(DeviceListError::DeviceAlreadyExists));
         }
         device_ids.push(new_device.device_id.clone());
 
         // Reorder devices (determine primary device again)
         devices_data.push(new_device.clone());
         migration::reorder_device_list(&user_id, device_ids, &devices_data);
 
         // Put new device
         let put_device = Put::builder()
           .table_name(devices_table::NAME)
           .set_item(Some(new_device.into()))
           .condition_expression(
             "attribute_not_exists(#user_id) AND attribute_not_exists(#item_id)",
           )
           .expression_attribute_names("#user_id", ATTR_USER_ID)
           .expression_attribute_names("#item_id", ATTR_ITEM_ID)
           .build();
         let put_device_operation =
           TransactWriteItem::builder().put(put_device).build();
 
         let update_info = UpdateOperationInfo::identity_generated()
           .with_ddb_operation(put_device_operation);
         Ok(update_info)
       })
       .await?;
 
     Ok(())
   }
 
   /// Removes device from user's device list. If the device doesn't exist, the
   /// operation fails. Transactionally generates new device list version.
   pub async fn remove_device(
     &self,
     user_id: impl Into<String>,
     device_id: impl AsRef<str>,
   ) -> Result<(), Error> {
     let user_id: String = user_id.into();
     let device_id = device_id.as_ref();
     self
       .transact_update_devicelist(&user_id, |device_ids, mut devices_data| {
         let device_exists = device_ids.iter().any(|id| id == device_id);
         if !device_exists {
           warn!(
             "Device doesn't exist in user's device list \
           (userID={}, deviceID={})",
             &user_id, device_id
           );
           return Err(Error::DeviceList(DeviceListError::DeviceNotFound));
         }
 
         device_ids.retain(|id| id != device_id);
 
         // Reorder devices (determine primary device again)
         devices_data.retain(|d| d.device_id != device_id);
         migration::reorder_device_list(&user_id, device_ids, &devices_data);
 
         // Delete device DDB operation
         let delete_device = Delete::builder()
           .table_name(devices_table::NAME)
           .key(ATTR_USER_ID, AttributeValue::S(user_id.clone()))
           .key(
             ATTR_ITEM_ID,
             DeviceIDAttribute(device_id.to_string()).into(),
           )
           .condition_expression(
             "attribute_exists(#user_id) AND attribute_exists(#item_id)",
           )
           .expression_attribute_names("#user_id", ATTR_USER_ID)
           .expression_attribute_names("#item_id", ATTR_ITEM_ID)
           .build();
         let operation =
           TransactWriteItem::builder().delete(delete_device).build();
 
         let update_info = UpdateOperationInfo::identity_generated()
           .with_ddb_operation(operation);
         Ok(update_info)
       })
       .await?;
 
     Ok(())
   }
 
   /// applies updated device list received from primary device
   pub async fn apply_devicelist_update(
     &self,
     user_id: &str,
     update: DeviceListUpdate,
     // A function that receives previous and new device IDs and
     // returns boolean determining if the new device list is valid.
     validator_fn: impl Fn(&[&str], &[&str]) -> bool,
   ) -> Result<DeviceListRow, Error> {
     let new_list = update.devices.clone();
     self
       .transact_update_devicelist(user_id, |current_list, _| {
+        crate::device_list::verify_device_list_signatures(
+          current_list.first(),
+          &update,
+        )?;
+
         let previous_device_ids: Vec<&str> =
           current_list.iter().map(AsRef::as_ref).collect();
         let new_device_ids: Vec<&str> =
           new_list.iter().map(AsRef::as_ref).collect();
         if !validator_fn(&previous_device_ids, &new_device_ids) {
           warn!("Received invalid device list update");
           return Err(Error::DeviceList(
             DeviceListError::InvalidDeviceListUpdate,
           ));
         }
 
         debug!("Applying device list update");
         *current_list = new_list;
 
         Ok(UpdateOperationInfo::primary_device_issued(update))
       })
       .await
   }
 
   /// Performs a transactional update of the device list for the user. Afterwards
   /// generates a new device list and updates the timestamp in the users table.
   /// This is done in a transaction. Operation fails if the device list has been
   /// updated concurrently (timestamp mismatch).
   /// Returns the new device list row that has been saved to database.
   #[tracing::instrument(skip_all)]
   async fn transact_update_devicelist(
     &self,
     user_id: &str,
     // The closure performing a transactional update of the device list.
     // It receives two arguments:
     // 1. A mutable reference to the current device list (ordered device IDs).
     // 2. Details (full data) of the current devices (unordered).
     // The closure should return a [`UpdateOperationInfo`] object.
     action: impl FnOnce(
       &mut Vec<String>,
       Vec<DeviceRow>,
     ) -> Result<UpdateOperationInfo, Error>,
   ) -> Result<DeviceListRow, Error> {
     let previous_timestamp =
       get_current_devicelist_timestamp(self, user_id).await?;
     let current_devices_data = self.get_current_devices(user_id).await?;
     let mut device_ids = self
       .get_current_device_list(user_id)
       .await?
       .map(|device_list| device_list.device_ids)
       .unwrap_or_default();
 
     // Perform the update action, then generate new device list
     let update_info = action(&mut device_ids, current_devices_data)?;
 
     crate::device_list::verify_device_list_timestamp(
       previous_timestamp.as_ref(),
       update_info.timestamp.as_ref(),
     )?;
     let new_device_list = DeviceListRow::new(user_id, device_ids, &update_info);
 
     // Update timestamp in users table
     let timestamp_update_operation = device_list_timestamp_update_operation(
       user_id,
       previous_timestamp,
       new_device_list.timestamp,
     );
 
     // Put updated device list (a new version)
     let put_device_list = Put::builder()
       .table_name(devices_table::NAME)
       .set_item(Some(new_device_list.clone().into()))
       .condition_expression(
         "attribute_not_exists(#user_id) AND attribute_not_exists(#item_id)",
       )
       .expression_attribute_names("#user_id", ATTR_USER_ID)
       .expression_attribute_names("#item_id", ATTR_ITEM_ID)
       .build();
     let put_device_list_operation =
       TransactWriteItem::builder().put(put_device_list).build();
 
     let operations = if let Some(operation) = update_info.ddb_operation {
       vec![
         operation,
         put_device_list_operation,
         timestamp_update_operation,
       ]
     } else {
       vec![put_device_list_operation, timestamp_update_operation]
     };
 
     self
       .client
       .transact_write_items()
       .set_transact_items(Some(operations))
       .send()
       .await
       .map_err(|e| match DynamoDBError::from(e) {
         DynamoDBError::TransactionCanceledException(
           TransactionCanceledException {
             cancellation_reasons: Some(reasons),
             ..
           },
         ) if reasons
           .iter()
           .any(|reason| reason.code() == Some("ConditionalCheckFailed")) =>
         {
           Error::DeviceList(DeviceListError::ConcurrentUpdateError)
         }
         other => {
           error!(
             errorType = error_types::DEVICE_LIST_DB_LOG,
             "Device list update transaction failed: {:?}", other
           );
           Error::AwsSdk(other)
         }
       })?;
 
     Ok(new_device_list)
   }
 
   /// Deletes all user data from devices table
   #[tracing::instrument(skip_all)]
   pub async fn delete_devices_table_rows_for_user(
     &self,
     user_id: impl Into<String>,
   ) -> Result<(), Error> {
     // 1. get all rows
     // 2. batch write delete all
 
     // we project only the primary keys so we can pass these directly to delete requests
     let primary_keys = self
       .client
       .query()
       .table_name(devices_table::NAME)
       .projection_expression("#user_id, #item_id")
       .key_condition_expression("#user_id = :user_id")
       .expression_attribute_names("#user_id", ATTR_USER_ID)
       .expression_attribute_names("#item_id", ATTR_ITEM_ID)
       .expression_attribute_values(
         ":user_id",
         AttributeValue::S(user_id.into()),
       )
       .consistent_read(true)
       .send()
       .await
       .map_err(|e| {
         error!(
           errorType = error_types::DEVICE_LIST_DB_LOG,
           "Failed to list user's items in devices table: {:?}", e
         );
         Error::AwsSdk(e.into())
       })?
       .items
       .unwrap_or_default();
 
     let delete_requests = primary_keys
       .into_iter()
       .map(|item| {
         let request = DeleteRequest::builder().set_key(Some(item)).build();
         WriteRequest::builder().delete_request(request).build()
       })
       .collect::<Vec<_>>();
 
     // TODO: We can use the batch write helper from comm-services-lib when integrated
     for batch in delete_requests.chunks(25) {
       self
         .client
         .batch_write_item()
         .request_items(devices_table::NAME, batch.to_vec())
         .send()
         .await
         .map_err(|e| {
           error!(
             errorType = error_types::DEVICE_LIST_DB_LOG,
             "Failed to batch delete items from devices table: {:?}", e
           );
           Error::AwsSdk(e.into())
         })?;
     }
 
     Ok(())
   }
 }
 
 /// Gets timestamp of user's current device list. Returns None if the user
 /// doesn't have a device list yet. Storing the timestamp in the users table is
 /// required for consistency. It's used as a condition when updating the device
 /// list.
 #[tracing::instrument(skip_all)]
 async fn get_current_devicelist_timestamp(
   db: &crate::database::DatabaseClient,
   user_id: impl Into<String>,
 ) -> Result<Option<DateTime<Utc>>, Error> {
   let response = db
     .client
     .get_item()
     .table_name(USERS_TABLE)
     .key(USERS_TABLE_PARTITION_KEY, AttributeValue::S(user_id.into()))
     .projection_expression(USERS_TABLE_DEVICELIST_TIMESTAMP_ATTRIBUTE_NAME)
     .send()
     .await
     .map_err(|e| {
       error!(
         errorType = error_types::DEVICE_LIST_DB_LOG,
         "Failed to get user's device list timestamp: {:?}", e
       );
       Error::AwsSdk(e.into())
     })?;
 
   let mut user_item = response.item.unwrap_or_default();
   let raw_datetime =
     user_item.remove(USERS_TABLE_DEVICELIST_TIMESTAMP_ATTRIBUTE_NAME);
 
   // existing records will not have this field when
   // updating device list for the first time
   if raw_datetime.is_none() {
     return Ok(None);
   }
 
   let timestamp = DateTime::<Utc>::try_from_attr(
     USERS_TABLE_DEVICELIST_TIMESTAMP_ATTRIBUTE_NAME,
     raw_datetime,
   )?;
   Ok(Some(timestamp))
 }
 
 /// Generates update expression for current device list timestamp in users table.
 /// The previous timestamp is used as a condition to ensure that the value hasn't changed
 /// since we got it. This avoids race conditions when updating the device list.
 fn device_list_timestamp_update_operation(
   user_id: impl Into<String>,
   previous_timestamp: Option<DateTime<Utc>>,
   new_timestamp: DateTime<Utc>,
 ) -> TransactWriteItem {
   let update_builder = match previous_timestamp {
     Some(previous_timestamp) => Update::builder()
       .condition_expression("#device_list_timestamp = :previous_timestamp")
       .expression_attribute_values(
         ":previous_timestamp",
         AttributeValue::S(previous_timestamp.to_rfc3339()),
       ),
     // If there's no previous timestamp, the attribute shouldn't exist yet
     None => Update::builder()
       .condition_expression("attribute_not_exists(#device_list_timestamp)"),
   };
 
   let update = update_builder
     .table_name(USERS_TABLE)
     .key(USERS_TABLE_PARTITION_KEY, AttributeValue::S(user_id.into()))
     .update_expression("SET #device_list_timestamp = :new_timestamp")
     .expression_attribute_names(
       "#device_list_timestamp",
       USERS_TABLE_DEVICELIST_TIMESTAMP_ATTRIBUTE_NAME,
     )
     .expression_attribute_values(
       ":new_timestamp",
       AttributeValue::S(new_timestamp.to_rfc3339()),
     )
     .build();
 
   TransactWriteItem::builder().update(update).build()
 }
 
 /// Helper function to query rows by given sort key prefix
 fn query_rows_with_prefix(
   db: &crate::database::DatabaseClient,
   user_id: impl Into<String>,
   prefix: &'static str,
 ) -> QueryFluentBuilder {
   db.client
     .query()
     .table_name(devices_table::NAME)
     .key_condition_expression(
       "#user_id = :user_id AND begins_with(#item_id, :device_prefix)",
     )
     .expression_attribute_names("#user_id", ATTR_USER_ID)
     .expression_attribute_names("#item_id", ATTR_ITEM_ID)
     .expression_attribute_values(":user_id", AttributeValue::S(user_id.into()))
     .expression_attribute_values(
       ":device_prefix",
       AttributeValue::S(prefix.to_string()),
     )
     .consistent_read(true)
 }
 
 /// [`transact_update_devicelist()`] closure result
 struct UpdateOperationInfo {
   /// (optional) transactional DDB operation to be performed
   /// when updating the device list.
   ddb_operation: Option<TransactWriteItem>,
   /// new device list timestamp. Defaults to `Utc::now()`
   /// for Identity-generated device lists.
   timestamp: Option<DateTime<Utc>>,
   current_signature: Option<String>,
   last_signature: Option<String>,
 }
 
 impl UpdateOperationInfo {
   fn identity_generated() -> Self {
     Self {
       ddb_operation: None,
       timestamp: None,
       current_signature: None,
       last_signature: None,
     }
   }
 
   fn primary_device_issued(source: DeviceListUpdate) -> Self {
     Self {
       ddb_operation: None,
       timestamp: Some(source.timestamp),
       current_signature: source.current_primary_signature,
       last_signature: source.last_primary_signature,
     }
   }
 
   fn with_ddb_operation(mut self, operation: TransactWriteItem) -> Self {
     self.ddb_operation = Some(operation);
     self
   }
 }
 
 // Helper module for "migration" code into new device list schema.
 // We can get rid of this when primary device takes over the responsibility
 // of managing the device list.
 mod migration {
   use std::{cmp::Ordering, collections::HashSet};
   use tracing::{debug, error, info};
 
   use super::*;
 
   #[tracing::instrument(skip_all)]
   pub(super) fn reorder_device_list(
     user_id: &str,
     list: &mut [String],
     devices_data: &[DeviceRow],
   ) {
     if !verify_device_list_match(list, devices_data) {
       error!(
         errorType = error_types::DEVICE_LIST_DB_LOG,
         "Found corrupt device list for user (userID={})!", user_id
       );
       return;
     }
 
     let Some(first_device) = list.first() else {
       debug!("Skipping device list rotation. Nothing to reorder.");
       return;
     };
     let Some(primary_device) = determine_primary_device(devices_data) else {
       info!(
         "No valid primary device found for user (userID={}).\
         Skipping device list reorder.",
         user_id
       );
       return;
     };
 
     if first_device == &primary_device.device_id {
       debug!("Skipping device list reorder. Primary device is already first");
       return;
     }
 
     // swap primary device with the first one
     let Some(primary_device_idx) =
       list.iter().position(|id| id == &primary_device.device_id)
     else {
       error!(
         errorType = error_types::DEVICE_LIST_DB_LOG,
         "Primary device not found in device list (userID={})", user_id
       );
       return;
     };
     list.swap(0, primary_device_idx);
     info!("Reordered device list for user (userID={})", user_id);
   }
 
   // checks if device list matches given devices data
   #[tracing::instrument(skip_all)]
   fn verify_device_list_match(
     list: &[String],
     devices_data: &[DeviceRow],
   ) -> bool {
     if list.len() != devices_data.len() {
       error!(
         errorType = error_types::DEVICE_LIST_DB_LOG,
         "Device list length mismatch!"
       );
       return false;
     }
 
     let actual_device_ids = devices_data
       .iter()
       .map(|device| &device.device_id)
       .collect::<HashSet<_>>();
 
     let device_list_set = list.iter().collect::<HashSet<_>>();
 
     if let Some(corrupt_device_id) = device_list_set
       .symmetric_difference(&actual_device_ids)
       .next()
     {
       error!(
         errorType = error_types::DEVICE_LIST_DB_LOG,
         "Device list is corrupt (unknown deviceID={})", corrupt_device_id
       );
       return false;
     }
 
     true
   }
 
   /// Returns reference to primary device (if any) from given list of devices
   /// or None if there's no valid primary device.
   fn determine_primary_device(devices: &[DeviceRow]) -> Option<&DeviceRow> {
     // 1. Find mobile devices with valid token
     // 2. Prioritize these with latest code version
     // 3. If there's a tie, select the one with latest login time
 
     let mut mobile_devices = devices
       .iter()
       .filter(|device| {
         device.device_type == DeviceType::Ios
           || device.device_type == DeviceType::Android
       })
       .collect::<Vec<_>>();
 
     mobile_devices.sort_by(|a, b| {
       let code_version_cmp = b.code_version.cmp(&a.code_version);
       if code_version_cmp == Ordering::Equal {
         b.login_time.cmp(&a.login_time)
       } else {
         code_version_cmp
       }
     });
     mobile_devices.first().cloned()
   }
 
   #[cfg(test)]
   mod tests {
     use super::*;
     use chrono::Duration;
 
     #[test]
     fn reorder_skips_no_devices() {
       let mut list = vec![];
       reorder_device_list("", &mut list, &[]);
       assert_eq!(list, Vec::<String>::new());
     }
 
     #[test]
     fn reorder_skips_single_device() {
       let mut list = vec!["test".into()];
       let devices_data =
         vec![create_test_device("test", DeviceType::Web, 0, Utc::now())];
 
       reorder_device_list("", &mut list, &devices_data);
       assert_eq!(list, vec!["test"]);
     }
 
     #[test]
     fn reorder_skips_for_valid_list() {
       let mut list = vec!["mobile".into(), "web".into()];
       let devices_data = vec![
         create_test_device("mobile", DeviceType::Android, 1, Utc::now()),
         create_test_device("web", DeviceType::Web, 0, Utc::now()),
       ];
 
       reorder_device_list("", &mut list, &devices_data);
       assert_eq!(list, vec!["mobile", "web"]);
     }
 
     #[test]
     fn reorder_swaps_primary_device_when_possible() {
       let mut list = vec!["web".into(), "mobile".into()];
       let devices_data = vec![
         create_test_device("web", DeviceType::Web, 0, Utc::now()),
         create_test_device("mobile", DeviceType::Android, 1, Utc::now()),
       ];
 
       reorder_device_list("", &mut list, &devices_data);
       assert_eq!(list, vec!["mobile", "web"]);
     }
 
     #[test]
     fn determine_primary_device_returns_none_for_empty_list() {
       let devices = vec![];
       assert!(determine_primary_device(&devices).is_none());
     }
 
     #[test]
     fn determine_primary_device_returns_none_for_web_only() {
       let devices =
         vec![create_test_device("web", DeviceType::Web, 0, Utc::now())];
 
       assert!(
         determine_primary_device(&devices).is_none(),
         "Primary device should be None for web-only devices"
       );
     }
 
     #[test]
     fn determine_primary_device_prioritizes_mobile() {
       let devices = vec![
         create_test_device("mobile", DeviceType::Android, 0, Utc::now()),
         create_test_device("web", DeviceType::Web, 0, Utc::now()),
       ];
 
       let primary_device = determine_primary_device(&devices)
         .expect("Primary device should be present");
       assert_eq!(
         primary_device.device_id, "mobile",
         "Primary device should be mobile"
       );
     }
 
     #[test]
     fn determine_primary_device_prioritizes_latest_code_version() {
       let devices_with_latest_code_version = vec![
         create_test_device("mobile1", DeviceType::Android, 1, Utc::now()),
         create_test_device("mobile2", DeviceType::Android, 2, Utc::now()),
         create_test_device("web", DeviceType::Web, 0, Utc::now()),
       ];
 
       let primary_device =
         determine_primary_device(&devices_with_latest_code_version)
           .expect("Primary device should be present");
 
       assert_eq!(
         primary_device.device_id, "mobile2",
         "Primary device should be mobile with latest code version"
       );
     }
 
     #[test]
     fn determine_primary_device_prioritizes_latest_login_time() {
       let devices = vec![
         create_test_device("mobile1_today", DeviceType::Ios, 1, Utc::now()),
         create_test_device(
           "mobile2_yesterday",
           DeviceType::Android,
           1,
           Utc::now() - Duration::days(1),
         ),
         create_test_device("web", DeviceType::Web, 0, Utc::now()),
       ];
 
       let primary_device = determine_primary_device(&devices)
         .expect("Primary device should be present");
 
       assert_eq!(
         primary_device.device_id, "mobile1_today",
         "Primary device should be mobile with latest login time"
       );
     }
 
     #[test]
     fn determine_primary_device_keeps_deterministic_order() {
       // Given two identical devices, the first one should be selected as primary
       let today = Utc::now();
       let devices_with_latest_code_version = vec![
         create_test_device("mobile1", DeviceType::Android, 1, today),
         create_test_device("mobile2", DeviceType::Android, 1, today),
       ];
 
       let primary_device =
         determine_primary_device(&devices_with_latest_code_version)
           .expect("Primary device should be present");
 
       assert_eq!(
         primary_device.device_id, "mobile1",
         "Primary device selection should be deterministic"
       );
     }
 
     #[test]
     fn determine_primary_device_all_rules_together() {
       use DeviceType::{Android, Ios, Web};
       let today = Utc::now();
       let yesterday = today - Duration::days(1);
 
       let devices = vec![
         create_test_device("mobile1_today", Android, 1, today),
         create_test_device("mobile2_today", Android, 2, today),
         create_test_device("mobile3_yesterday", Ios, 1, yesterday),
         create_test_device("mobile4_yesterday", Ios, 2, yesterday),
         create_test_device("web", Web, 5, today),
       ];
 
       let primary_device = determine_primary_device(&devices)
         .expect("Primary device should be present");
 
       assert_eq!(
         primary_device.device_id, "mobile2_today",
         "Primary device should be mobile with latest code version and login time"
     );
     }
 
     fn create_test_device(
       id: &str,
       platform: DeviceType,
       code_version: u64,
       login_time: DateTime<Utc>,
     ) -> DeviceRow {
       DeviceRow {
         user_id: "test".into(),
         device_id: id.into(),
         device_type: platform,
         device_key_info: IdentityKeyInfo {
           key_payload: "".into(),
           key_payload_signature: "".into(),
         },
         content_prekey: Prekey {
           prekey: "".into(),
           prekey_signature: "".into(),
         },
         notif_prekey: Prekey {
           prekey: "".into(),
           prekey_signature: "".into(),
         },
         code_version,
         login_time,
       }
     }
   }
 }
diff --git a/services/identity/src/device_list.rs b/services/identity/src/device_list.rs
index 6ee13a9d1..6427116ef 100644
--- a/services/identity/src/device_list.rs
+++ b/services/identity/src/device_list.rs
@@ -1,460 +1,501 @@
 use chrono::{DateTime, Duration, Utc};
 use std::collections::HashSet;
-use tracing::{error, warn};
+use tracing::{debug, error, warn};
 
 use crate::{
   constants::{error_types, DEVICE_LIST_TIMESTAMP_VALID_FOR},
   database::{DeviceListRow, DeviceListUpdate},
   ddb_utils::DateTimeExt,
   error::DeviceListError,
   grpc_services::protos::auth::UpdateDeviceListRequest,
 };
 
 // serde helper for serializing/deserializing
 // device list JSON payload
 #[derive(serde::Serialize, serde::Deserialize)]
 struct RawDeviceList {
   devices: Vec<String>,
   timestamp: i64,
 }
 
 /// Signed device list payload that is serializable to JSON.
 /// For the DDB payload, see [`DeviceListUpdate`]
 #[derive(serde::Serialize, serde::Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct SignedDeviceList {
   /// JSON-stringified [`RawDeviceList`]
   raw_device_list: String,
   /// Current primary device signature.
   /// NOTE: Present only when the payload is received from primary device.
   /// It's `None` for Identity-generated device-lists
   #[serde(default)]
   #[serde(skip_serializing_if = "Option::is_none")]
   cur_primary_signature: Option<String>,
   /// Previous primary device signature. Present only
   /// if primary device has changed since last update.
   #[serde(default)]
   #[serde(skip_serializing_if = "Option::is_none")]
   last_primary_signature: Option<String>,
 }
 
 impl SignedDeviceList {
   fn as_raw(&self) -> Result<RawDeviceList, tonic::Status> {
     // The device list payload is sent as an escaped JSON payload.
     // Escaped double quotes need to be trimmed before attempting to deserialize
     serde_json::from_str(&self.raw_device_list.replace(r#"\""#, r#"""#))
       .map_err(|err| {
         warn!("Failed to deserialize raw device list: {}", err);
         tonic::Status::invalid_argument("invalid device list payload")
       })
   }
 
   /// Serializes the signed device list to a JSON string
   pub fn as_json_string(&self) -> Result<String, tonic::Status> {
     serde_json::to_string(self).map_err(|err| {
       error!(
         errorType = error_types::GRPC_SERVICES_LOG,
         "Failed to serialize device list updates: {}", err
       );
       tonic::Status::failed_precondition("unexpected error")
     })
   }
 }
 
 impl TryFrom<DeviceListRow> for SignedDeviceList {
   type Error = tonic::Status;
 
   fn try_from(row: DeviceListRow) -> Result<Self, Self::Error> {
     let raw_list = RawDeviceList {
       devices: row.device_ids,
       timestamp: row.timestamp.timestamp_millis(),
     };
     let stringified_list = serde_json::to_string(&raw_list).map_err(|err| {
       error!(
         errorType = error_types::GRPC_SERVICES_LOG,
         "Failed to serialize raw device list: {}", err
       );
       tonic::Status::failed_precondition("unexpected error")
     })?;
 
     Ok(Self {
       raw_device_list: stringified_list,
       cur_primary_signature: row.current_primary_signature,
       last_primary_signature: row.last_primary_signature,
     })
   }
 }
 
 impl TryFrom<UpdateDeviceListRequest> for SignedDeviceList {
   type Error = tonic::Status;
   fn try_from(request: UpdateDeviceListRequest) -> Result<Self, Self::Error> {
     serde_json::from_str(&request.new_device_list).map_err(|err| {
       warn!("Failed to deserialize device list update: {}", err);
       tonic::Status::invalid_argument("invalid device list payload")
     })
   }
 }
 
 impl TryFrom<SignedDeviceList> for DeviceListUpdate {
   type Error = tonic::Status;
   fn try_from(signed_list: SignedDeviceList) -> Result<Self, Self::Error> {
     let RawDeviceList {
       devices,
       timestamp: raw_timestamp,
     } = signed_list.as_raw()?;
     let timestamp = DateTime::<Utc>::from_utc_timestamp_millis(raw_timestamp)
       .ok_or_else(|| {
       error!(
         errorType = error_types::GRPC_SERVICES_LOG,
         "Failed to parse RawDeviceList timestamp!"
       );
       tonic::Status::invalid_argument("invalid timestamp")
     })?;
     Ok(DeviceListUpdate {
       devices,
       timestamp,
       current_primary_signature: signed_list.cur_primary_signature,
       last_primary_signature: signed_list.last_primary_signature,
+      raw_payload: signed_list.raw_device_list,
     })
   }
 }
 
 /// Returns `true` if given timestamp is valid. The timestamp is considered
 /// valid under the following condition:
 /// - `new_timestamp` is greater than `previous_timestamp` (if provided)
 /// - `new_timestamp` is not older than [`DEVICE_LIST_TIMESTAMP_VALID_FOR`]
 ///
 /// Note: For Identity-managed device lists, the timestamp can be `None`.
 /// Verification is then skipped
 fn is_new_timestamp_valid(
   previous_timestamp: Option<&DateTime<Utc>>,
   new_timestamp: Option<&DateTime<Utc>>,
 ) -> bool {
   let Some(new_timestamp) = new_timestamp else {
     return true;
   };
 
   if let Some(previous_timestamp) = previous_timestamp {
     if new_timestamp < previous_timestamp {
       return false;
     }
   }
 
   let timestamp_valid_duration =
     Duration::from_std(DEVICE_LIST_TIMESTAMP_VALID_FOR)
       .expect("FATAL - Invalid duration constant provided");
 
   Utc::now().signed_duration_since(new_timestamp) < timestamp_valid_duration
 }
 
 /// Returns error if new timestamp is invalid. The timestamp is considered
 /// valid under the following condition:
 /// - `new_timestamp` is greater than `previous_timestamp` (if provided)
 /// - `new_timestamp` is not older than [`DEVICE_LIST_TIMESTAMP_VALID_FOR`]
 ///
 /// Note: For Identity-managed device lists, the timestamp can be `None`.
 /// Verification is then skipped
 pub fn verify_device_list_timestamp(
   previous_timestamp: Option<&DateTime<Utc>>,
   new_timestamp: Option<&DateTime<Utc>>,
 ) -> Result<(), DeviceListError> {
   if !is_new_timestamp_valid(previous_timestamp, new_timestamp) {
     return Err(DeviceListError::InvalidDeviceListUpdate);
   }
   Ok(())
 }
 
+pub fn verify_device_list_signatures(
+  previous_primary_device_id: Option<&String>,
+  new_device_list: &DeviceListUpdate,
+) -> Result<(), DeviceListError> {
+  let Some(primary_device_id) = new_device_list.devices.first() else {
+    return Ok(());
+  };
+
+  // verify current signature
+  if let Some(signature) = &new_device_list.current_primary_signature {
+    crate::grpc_utils::ed25519_verify(
+      primary_device_id,
+      &new_device_list.raw_payload,
+      signature,
+    )
+    .map_err(|err| {
+      debug!("curPrimarySignature verification failed: {err}");
+      DeviceListError::InvalidSignature
+    })?;
+  }
+
+  // verify last signature if primary device changed
+  if let (Some(previous_primary_id), Some(last_signature)) = (
+    previous_primary_device_id.filter(|prev| *prev != primary_device_id),
+    &new_device_list.last_primary_signature,
+  ) {
+    crate::grpc_utils::ed25519_verify(
+      previous_primary_id,
+      &new_device_list.raw_payload,
+      last_signature,
+    )
+    .map_err(|err| {
+      debug!("lastPrimarySignature verification failed: {err}");
+      DeviceListError::InvalidSignature
+    })?;
+  }
+
+  Ok(())
+}
+
 pub mod validation {
   use super::*;
   /// Returns `true` if `new_device_list` contains exactly one more new device
   /// compared to `previous_device_list`
   fn is_device_added(
     previous_device_list: &[&str],
     new_device_list: &[&str],
   ) -> bool {
     let previous_set: HashSet<_> = previous_device_list.iter().collect();
     let new_set: HashSet<_> = new_device_list.iter().collect();
 
     return new_set.difference(&previous_set).count() == 1;
   }
 
   /// Returns `true` if `new_device_list` contains exactly one fewer device
   /// compared to `previous_device_list`
   fn is_device_removed(
     previous_device_list: &[&str],
     new_device_list: &[&str],
   ) -> bool {
     let previous_set: HashSet<_> = previous_device_list.iter().collect();
     let new_set: HashSet<_> = new_device_list.iter().collect();
 
     return previous_set.difference(&new_set).count() == 1;
   }
 
   fn primary_device_changed(
     previous_device_list: &[&str],
     new_device_list: &[&str],
   ) -> bool {
     let previous_primary = previous_device_list.first();
     let new_primary = new_device_list.first();
 
     new_primary != previous_primary
   }
 
   /// Verifies if exactly one device has been replaced.
   /// No reorders are permitted. Both lists have to have the same length.
   fn is_device_replaced(
     previous_device_list: &[&str],
     new_device_list: &[&str],
   ) -> bool {
     if previous_device_list.len() != new_device_list.len() {
       return false;
     }
 
     // exactly 1 different device ID
     std::iter::zip(previous_device_list, new_device_list)
       .filter(|(a, b)| a != b)
       .count()
       == 1
   }
 
   // This is going to be used when doing primary devicd keys rotation
   #[allow(unused)]
   pub fn primary_device_rotation_validator(
     previous_device_list: &[&str],
     new_device_list: &[&str],
   ) -> bool {
     primary_device_changed(previous_device_list, new_device_list)
       && !is_device_replaced(&previous_device_list[1..], &new_device_list[1..])
   }
 
   /// The `UpdateDeviceList` RPC should be able to either add or remove
   /// one device, and it cannot currently switch primary devices.
   /// The RPC is also able to replace a keyserver device
   pub fn update_device_list_rpc_validator(
     previous_device_list: &[&str],
     new_device_list: &[&str],
   ) -> bool {
     if primary_device_changed(previous_device_list, new_device_list) {
       return false;
     }
 
     // allow replacing a keyserver
     if is_device_replaced(previous_device_list, new_device_list) {
       return true;
     }
 
     let is_added = is_device_added(previous_device_list, new_device_list);
     let is_removed = is_device_removed(previous_device_list, new_device_list);
 
     is_added != is_removed
   }
 
   #[cfg(test)]
   mod tests {
     use super::*;
 
     #[test]
     fn test_device_added_or_removed() {
       use std::ops::Not;
 
       let list1 = vec!["device1"];
       let list2 = vec!["device1", "device2"];
 
       assert!(is_device_added(&list1, &list2));
       assert!(is_device_removed(&list1, &list2).not());
 
       assert!(is_device_added(&list2, &list1).not());
       assert!(is_device_removed(&list2, &list1));
 
       assert!(is_device_added(&list1, &list1).not());
       assert!(is_device_removed(&list1, &list1).not());
     }
 
     #[test]
     fn test_primary_device_changed() {
       use std::ops::Not;
 
       let list1 = vec!["device1"];
       let list2 = vec!["device1", "device2"];
       let list3 = vec!["device2"];
 
       assert!(primary_device_changed(&list1, &list2).not());
       assert!(primary_device_changed(&list1, &list3));
     }
 
     #[test]
     fn test_device_replaced() {
       use std::ops::Not;
 
       let list1 = vec!["device1"];
       let list2 = vec!["device2"];
       let list3 = vec!["device1", "device2"];
       let list4 = vec!["device2", "device1"];
       let list5 = vec!["device2", "device3"];
 
       assert!(is_device_replaced(&list1, &list2), "Singleton replacement");
       assert!(is_device_replaced(&list4, &list5), "Standard replacement");
       assert!(is_device_replaced(&list1, &list3).not(), "Length unequal");
       assert!(is_device_replaced(&list3, &list3).not(), "Unchanged");
       assert!(is_device_replaced(&list3, &list4).not(), "Reorder");
     }
   }
 }
 
 #[cfg(test)]
 mod tests {
   use super::*;
 
   #[test]
   fn deserialize_device_list_signature() {
     let payload_with_signature = r#"{"rawDeviceList":"{\"devices\":[\"device1\"],\"timestamp\":111111111}","curPrimarySignature":"foo"}"#;
     let payload_without_signatures = r#"{"rawDeviceList":"{\"devices\":[\"device1\",\"device2\"],\"timestamp\":222222222}"}"#;
 
     let list_with_signature: SignedDeviceList =
       serde_json::from_str(payload_with_signature).unwrap();
     let list_without_signatures: SignedDeviceList =
       serde_json::from_str(payload_without_signatures).unwrap();
 
     assert_eq!(
       list_with_signature.cur_primary_signature,
       Some("foo".to_string())
     );
     assert!(list_with_signature.last_primary_signature.is_none());
 
     assert!(list_without_signatures.cur_primary_signature.is_none());
     assert!(list_without_signatures.last_primary_signature.is_none());
   }
 
   #[test]
   fn serialize_device_list_signatures() {
     let raw_list = r#"{"devices":["device1"],"timestamp":111111111}"#;
 
     let expected_payload_without_signatures = r#"{"rawDeviceList":"{\"devices\":[\"device1\"],\"timestamp\":111111111}"}"#;
     let device_list_without_signature = SignedDeviceList {
       raw_device_list: raw_list.to_string(),
       cur_primary_signature: None,
       last_primary_signature: None,
     };
     assert_eq!(
       device_list_without_signature.as_json_string().unwrap(),
       expected_payload_without_signatures
     );
 
     let expected_payload_with_signature = r#"{"rawDeviceList":"{\"devices\":[\"device1\"],\"timestamp\":111111111}","curPrimarySignature":"foo"}"#;
     let device_list_with_cur_signature = SignedDeviceList {
       raw_device_list: raw_list.to_string(),
       cur_primary_signature: Some("foo".to_string()),
       last_primary_signature: None,
     };
     assert_eq!(
       device_list_with_cur_signature.as_json_string().unwrap(),
       expected_payload_with_signature
     );
   }
 
   #[test]
   fn serialize_device_list_updates() {
     let raw_updates = vec![
       create_device_list_row(RawDeviceList {
         devices: vec!["device1".into()],
         timestamp: 111111111,
       }),
       create_device_list_row(RawDeviceList {
         devices: vec!["device1".into(), "device2".into()],
         timestamp: 222222222,
       }),
     ];
 
     let expected_raw_list1 = r#"{"devices":["device1"],"timestamp":111111111}"#;
     let expected_raw_list2 =
       r#"{"devices":["device1","device2"],"timestamp":222222222}"#;
 
     let signed_updates = raw_updates
       .into_iter()
       .map(SignedDeviceList::try_from)
       .collect::<Result<Vec<_>, _>>()
       .expect("signing device list updates failed");
 
     assert_eq!(signed_updates[0].raw_device_list, expected_raw_list1);
     assert_eq!(signed_updates[1].raw_device_list, expected_raw_list2);
 
     let stringified_updates = signed_updates
       .iter()
       .map(serde_json::to_string)
       .collect::<Result<Vec<_>, _>>()
       .expect("serialize signed device lists failed");
 
     let expected_stringified_list1 = r#"{"rawDeviceList":"{\"devices\":[\"device1\"],\"timestamp\":111111111}"}"#;
     let expected_stringified_list2 = r#"{"rawDeviceList":"{\"devices\":[\"device1\",\"device2\"],\"timestamp\":222222222}"}"#;
 
     assert_eq!(stringified_updates[0], expected_stringified_list1);
     assert_eq!(stringified_updates[1], expected_stringified_list2);
   }
 
   #[test]
   fn deserialize_device_list_update() {
     let raw_payload = r#"{"rawDeviceList":"{\"devices\":[\"device1\",\"device2\"],\"timestamp\":123456789}"}"#;
     let request = UpdateDeviceListRequest {
       new_device_list: raw_payload.to_string(),
     };
 
     let signed_list = SignedDeviceList::try_from(request)
       .expect("Failed to parse SignedDeviceList");
     let update = DeviceListUpdate::try_from(signed_list)
       .expect("Failed to parse DeviceListUpdate from signed list");
 
     let expected_timestamp =
       DateTime::<Utc>::from_utc_timestamp_millis(123456789).unwrap();
 
     assert_eq!(update.timestamp, expected_timestamp);
     assert_eq!(
       update.devices,
       vec!["device1".to_string(), "device2".to_string()]
     );
   }
 
   #[test]
   fn test_timestamp_validation() {
     let valid_timestamp = Utc::now() - Duration::milliseconds(100);
     let previous_timestamp = Utc::now() - Duration::seconds(10);
     let too_old_timestamp = previous_timestamp - Duration::seconds(1);
     let expired_timestamp = Utc::now() - Duration::minutes(20);
 
     assert!(
       verify_device_list_timestamp(
         Some(&previous_timestamp),
         Some(&valid_timestamp)
       )
       .is_ok(),
       "Valid timestamp should pass verification"
     );
     assert!(
       verify_device_list_timestamp(
         Some(&previous_timestamp),
         Some(&too_old_timestamp)
       )
       .is_err(),
       "Timestamp older than previous, should fail verification"
     );
     assert!(
       verify_device_list_timestamp(None, Some(&expired_timestamp)).is_err(),
       "Expired timestamp should fail verification"
     );
     assert!(
       verify_device_list_timestamp(None, None).is_ok(),
       "No provided timestamp should pass"
     );
   }
 
   /// helper for mocking DB rows from raw device list payloads
   fn create_device_list_row(raw_list: RawDeviceList) -> DeviceListRow {
     DeviceListRow {
       user_id: "".to_string(),
       device_ids: raw_list.devices,
       timestamp: DateTime::<Utc>::from_utc_timestamp_millis(raw_list.timestamp)
         .unwrap(),
       current_primary_signature: None,
       last_primary_signature: None,
     }
   }
 }
diff --git a/services/identity/src/error.rs b/services/identity/src/error.rs
index cd52eeb6c..e51415ec5 100644
--- a/services/identity/src/error.rs
+++ b/services/identity/src/error.rs
@@ -1,63 +1,64 @@
 use comm_lib::aws::DynamoDBError;
 use comm_lib::database::DBItemError;
 use tracing::error;
 
 #[derive(
   Debug, derive_more::Display, derive_more::From, derive_more::Error,
 )]
 pub enum Error {
   #[display(...)]
   AwsSdk(DynamoDBError),
   #[display(...)]
   Attribute(DBItemError),
   #[display(...)]
   Transport(tonic::transport::Error),
   #[display(...)]
   Status(tonic::Status),
   #[display(...)]
   MissingItem,
   #[display(...)]
   DeviceList(DeviceListError),
   #[display(...)]
   MalformedItem,
   #[display(...)]
   Serde(serde_json::Error),
   #[display(...)]
   CannotOverwrite,
   #[display(...)]
   OneTimeKeyUploadLimitExceeded,
   #[display(...)]
   MaxRetriesExceeded,
   #[display(...)]
   InvalidFormat,
   #[display(...)]
   NotEnoughOneTimeKeys,
 }
 
 #[derive(Debug, derive_more::Display, derive_more::Error)]
 pub enum DeviceListError {
   DeviceAlreadyExists,
   DeviceNotFound,
   ConcurrentUpdateError,
   InvalidDeviceListUpdate,
+  InvalidSignature,
 }
 
 pub fn consume_error<T>(result: Result<T, Error>) {
   match result {
     Ok(_) => (),
     Err(e) => {
       error!("{}", e);
     }
   }
 }
 
 impl From<comm_lib::database::Error> for Error {
   fn from(value: comm_lib::database::Error) -> Self {
     use comm_lib::database::Error as E;
     match value {
       E::AwsSdk(err) => Self::AwsSdk(err),
       E::Attribute(err) => Self::Attribute(err),
       E::MaxRetriesExceeded => Self::MaxRetriesExceeded,
     }
   }
 }