diff --git a/services/identity/src/client_service.rs b/services/identity/src/client_service.rs
index b01c33143..c11405b3e 100644
--- a/services/identity/src/client_service.rs
+++ b/services/identity/src/client_service.rs
@@ -1,1007 +1,1022 @@
 use std::collections::HashMap;
 // Standard library imports
 use std::str::FromStr;
 
 // External crate imports
 use aws_sdk_dynamodb::Error as DynamoDBError;
 use comm_opaque2::grpc::protocol_error_to_grpc_status;
 use moka::future::Cache;
 use rand::rngs::OsRng;
 use siwe::eip55;
 use tonic::Response;
 use tracing::{debug, error};
 
 // Workspace crate imports
 use crate::client_service::client_proto::{
   inbound_keys_for_user_request, outbound_keys_for_user_request,
   AddReservedUsernamesRequest, DeleteUserRequest, Empty, GenerateNonceResponse,
   InboundKeyInfo, InboundKeysForUserRequest, InboundKeysForUserResponse,
   LogoutRequest, OpaqueLoginFinishRequest, OpaqueLoginFinishResponse,
   OpaqueLoginStartRequest, OpaqueLoginStartResponse, OutboundKeyInfo,
   OutboundKeysForUserRequest, OutboundKeysForUserResponse,
   RegistrationFinishRequest, RegistrationFinishResponse,
   RegistrationStartRequest, RegistrationStartResponse,
   RemoveReservedUsernameRequest, ReservedRegistrationStartRequest,
   ReservedWalletLoginRequest, UpdateUserPasswordFinishRequest,
   UpdateUserPasswordStartRequest, UpdateUserPasswordStartResponse,
   VerifyUserAccessTokenRequest, VerifyUserAccessTokenResponse,
   WalletLoginRequest, WalletLoginResponse,
 };
 use crate::config::CONFIG;
 use crate::database::{
   DBDeviceTypeInt, DatabaseClient, DeviceType, KeyPayload,
 };
 use crate::error::Error as DBError;
 use crate::grpc_utils::{DeviceInfoWithAuth, DeviceKeyUploadActions};
 use crate::id::generate_uuid;
 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};
 use crate::token::{AccessTokenData, AuthType};
 pub use client_proto::identity_client_service_server::{
   IdentityClientService, IdentityClientServiceServer,
 };
 
 pub mod client_proto {
   tonic::include_proto!("identity.client");
 }
 
 #[derive(Clone)]
 pub enum WorkflowInProgress {
   Registration(Box<UserRegistrationInfo>),
   Login(Box<UserLoginInfo>),
   Update(UpdateState),
 }
 
 #[derive(Clone)]
 pub struct UserRegistrationInfo {
   pub username: String,
   pub flattened_device_key_upload: FlattenedDeviceKeyUpload,
   pub user_id: Option<String>,
 }
 
 #[derive(Clone)]
 pub struct UserLoginInfo {
   pub user_id: String,
   pub flattened_device_key_upload: FlattenedDeviceKeyUpload,
   pub opaque_server_login: comm_opaque2::server::Login,
 }
 
 #[derive(Clone)]
 pub struct UpdateState {
   pub user_id: String,
 }
 
 #[derive(Clone)]
 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,
   cache: Cache<String, WorkflowInProgress>,
 }
 
 #[tonic::async_trait]
 impl IdentityClientService for ClientService {
   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);
 
     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 CONFIG.reserved_usernames.contains(&message.username)
       || is_valid_ethereum_address(&message.username)
     {
       return Err(tonic::Status::invalid_argument("username reserved"));
     }
 
     let registration_state = construct_user_registration_info(
       &message,
       None,
       message.username.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
-      .insert_into_cache(WorkflowInProgress::Registration(Box::new(
+      .cache
+      .insert_with_uuid_key(WorkflowInProgress::Registration(Box::new(
         registration_state,
       )))
       .await;
 
     let response = RegistrationStartResponse {
       session_id,
       opaque_registration_response: server_message,
     };
     Ok(Response::new(response))
   }
 
   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 CONFIG.reserved_usernames.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(),
     )?;
     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
-      .insert_into_cache(WorkflowInProgress::Registration(Box::new(
+      .cache
+      .insert_with_uuid_key(WorkflowInProgress::Registration(Box::new(
         registration_state,
       )))
       .await;
 
     let response = RegistrationStartResponse {
       session_id,
       opaque_registration_response: server_message,
     };
     Ok(Response::new(response))
   }
 
   async fn register_password_user_finish(
     &self,
     request: tonic::Request<RegistrationFinishRequest>,
   ) -> Result<tonic::Response<RegistrationFinishResponse>, tonic::Status> {
     let message = request.into_inner();
 
     if let Some(WorkflowInProgress::Registration(state)) =
       self.cache.get(&message.session_id)
     {
       self.cache.invalidate(&message.session_id).await;
 
       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 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)
         .await
         .map_err(handle_db_error)?;
 
       // Create access token
       let token = AccessTokenData::new(
         user_id.clone(),
         device_id,
         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 = RegistrationFinishResponse {
         user_id,
         access_token,
       };
       Ok(Response::new(response))
     } else {
       Err(tonic::Status::not_found("session not found"))
     }
   }
 
   async fn update_user_password_start(
     &self,
     request: tonic::Request<UpdateUserPasswordStartRequest>,
   ) -> Result<tonic::Response<UpdateUserPasswordStartResponse>, tonic::Status>
   {
     let message = request.into_inner();
 
     let token_is_valid = self
       .client
       .verify_access_token(
         message.user_id.clone(),
         message.device_id_key,
         message.access_token,
       )
       .await
       .map_err(handle_db_error)?;
 
     if !token_is_valid {
       return Err(tonic::Status::permission_denied("bad token"));
     }
 
     let server_registration = comm_opaque2::server::Registration::new();
     let server_message = server_registration
       .start(
         &CONFIG.server_setup,
         &message.opaque_registration_request,
         message.user_id.as_bytes(),
       )
       .map_err(protocol_error_to_grpc_status)?;
 
     let update_state = UpdateState {
       user_id: message.user_id,
     };
     let session_id = self
-      .insert_into_cache(WorkflowInProgress::Update(update_state))
+      .cache
+      .insert_with_uuid_key(WorkflowInProgress::Update(update_state))
       .await;
 
     let response = UpdateUserPasswordStartResponse {
       session_id,
       opaque_registration_response: server_message,
     };
     Ok(Response::new(response))
   }
 
   async fn update_user_password_finish(
     &self,
     request: tonic::Request<UpdateUserPasswordFinishRequest>,
   ) -> Result<tonic::Response<Empty>, tonic::Status> {
     let message = request.into_inner();
 
     if let Some(WorkflowInProgress::Update(state)) =
       self.cache.get(&message.session_id)
     {
       self.cache.invalidate(&message.session_id).await;
 
       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)?;
 
       self
         .client
         .update_user_password(state.user_id, password_file)
         .await
         .map_err(handle_db_error)?;
 
       let response = Empty {};
       Ok(Response::new(response))
     } else {
       Err(tonic::Status::not_found("session not found"))
     }
   }
 
   async fn login_password_user_start(
     &self,
     request: tonic::Request<OpaqueLoginStartRequest>,
   ) -> Result<tonic::Response<OpaqueLoginStartResponse>, tonic::Status> {
     let message = request.into_inner();
 
     debug!("Attempting to login 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::failed_precondition(
             "need keyserver message to claim username",
           ));
         }
 
         return Err(tonic::Status::not_found("user not found"));
       };
 
     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(&message, user_id, server_login)?;
 
     let session_id = self
-      .insert_into_cache(WorkflowInProgress::Login(Box::new(login_state)))
+      .cache
+      .insert_with_uuid_key(WorkflowInProgress::Login(Box::new(login_state)))
       .await;
 
     let response = Response::new(OpaqueLoginStartResponse {
       session_id,
       opaque_login_response: server_response,
     });
     Ok(response)
   }
 
   async fn login_password_user_finish(
     &self,
     request: tonic::Request<OpaqueLoginFinishRequest>,
   ) -> Result<tonic::Response<OpaqueLoginFinishResponse>, tonic::Status> {
     let message = request.into_inner();
 
     if let Some(WorkflowInProgress::Login(state)) =
       self.cache.get(&message.session_id)
     {
       self.cache.invalidate(&message.session_id).await;
 
       let mut server_login = state.opaque_server_login.clone();
       server_login
         .finish(&message.opaque_login_upload)
         .map_err(protocol_error_to_grpc_status)?;
 
       self
         .client
         .add_password_user_device_to_users_table(
           state.user_id.clone(),
           state.flattened_device_key_upload.clone(),
         )
         .await
         .map_err(handle_db_error)?;
 
       // Create access token
       let token = AccessTokenData::new(
         state.user_id.clone(),
         state.flattened_device_key_upload.device_id_key,
         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 = OpaqueLoginFinishResponse {
         user_id: state.user_id,
         access_token,
       };
       Ok(Response::new(response))
     } else {
       Err(tonic::Status::not_found("session not found"))
     }
   }
 
   async fn login_wallet_user(
     &self,
     request: tonic::Request<WalletLoginRequest>,
   ) -> Result<tonic::Response<WalletLoginResponse>, tonic::Status> {
     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(_) => self
         .client
         .remove_nonce_from_nonces_table(&parsed_message.nonce)
         .await
         .map_err(handle_db_error)?,
     };
 
     let wallet_address = eip55(&parsed_message.address);
 
     let flattened_device_key_upload =
       construct_flattened_device_key_upload(&message)?;
 
     let social_proof = message
       .social_proof()?
       .ok_or_else(|| tonic::Status::invalid_argument("malformed payload"))?;
 
     let user_id = match self
       .client
       .get_user_id_from_user_info(wallet_address.clone(), &AuthType::Wallet)
       .await
       .map_err(handle_db_error)?
     {
       Some(id) => {
         // User already exists, so we should update the DDB item
         self
           .client
           .add_wallet_user_device_to_users_table(
             id.clone(),
             flattened_device_key_upload.clone(),
             social_proof,
           )
           .await
           .map_err(handle_db_error)?;
         id
       }
       None => {
         // 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::failed_precondition(
             "need keyserver message to claim username",
           ));
         }
 
         // User doesn't exist yet and wallet address isn't reserved, so we
         // should add a new user in DDB
         self
           .client
           .add_wallet_user_to_users_table(
             flattened_device_key_upload.clone(),
             wallet_address,
             social_proof,
             None,
           )
           .await
           .map_err(handle_db_error)?
       }
     };
 
     // Create access token
     let token = AccessTokenData::new(
       user_id.clone(),
       flattened_device_key_upload.device_id_key,
       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 = WalletLoginResponse {
       user_id,
       access_token,
     };
     Ok(Response::new(response))
   }
 
   async fn login_reserved_wallet_user(
     &self,
     request: tonic::Request<ReservedWalletLoginRequest>,
   ) -> Result<tonic::Response<WalletLoginResponse>, tonic::Status> {
     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(_) => 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 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 = message
       .social_proof()?
       .ok_or_else(|| tonic::Status::invalid_argument("malformed payload"))?;
 
     self
       .client
       .add_wallet_user_to_users_table(
         flattened_device_key_upload.clone(),
         wallet_address,
         social_proof,
         Some(user_id.clone()),
       )
       .await
       .map_err(handle_db_error)?;
 
     let token = AccessTokenData::new(
       user_id.clone(),
       flattened_device_key_upload.device_id_key,
       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 = WalletLoginResponse {
       user_id,
       access_token,
     };
 
     Ok(Response::new(response))
   }
 
   async fn log_out_user(
     &self,
     request: tonic::Request<LogoutRequest>,
   ) -> Result<tonic::Response<Empty>, tonic::Status> {
     let message = request.into_inner();
 
     let token_is_valid = self
       .client
       .verify_access_token(
         message.user_id.clone(),
         message.device_id_key.clone(),
         message.access_token,
       )
       .await
       .map_err(handle_db_error)?;
 
     if !token_is_valid {
       return Err(tonic::Status::permission_denied("bad token"));
     }
 
     self
       .client
       .remove_device_from_users_table(
         message.user_id.clone(),
         message.device_id_key.clone(),
       )
       .await
       .map_err(handle_db_error)?;
 
     self
       .client
       .delete_access_token_data(message.user_id, message.device_id_key)
       .await
       .map_err(handle_db_error)?;
 
     let response = Empty {};
 
     Ok(Response::new(response))
   }
 
   async fn delete_user(
     &self,
     request: tonic::Request<DeleteUserRequest>,
   ) -> Result<tonic::Response<Empty>, tonic::Status> {
     let message = request.into_inner();
 
     let token_is_valid = self
       .client
       .verify_access_token(
         message.user_id.clone(),
         message.device_id_key,
         message.access_token,
       )
       .await
       .map_err(handle_db_error)?;
 
     if !token_is_valid {
       return Err(tonic::Status::permission_denied("bad token"));
     }
 
     self
       .client
       .delete_user(message.user_id)
       .await
       .map_err(handle_db_error)?;
 
     let response = Empty {};
 
     Ok(Response::new(response))
   }
 
   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)),
     }
   }
 
   async fn get_outbound_keys_for_user(
     &self,
     request: tonic::Request<OutboundKeysForUserRequest>,
   ) -> Result<tonic::Response<OutboundKeysForUserResponse>, tonic::Status> {
     let message = request.into_inner();
 
     use outbound_keys_for_user_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 devices_map = self
       .client
       .get_keys_for_user(user_ident, &auth_type, true)
       .await
       .map_err(handle_db_error)?
       .ok_or_else(|| match auth_type {
         AuthType::Password => tonic::Status::not_found("username not found"),
         AuthType::Wallet => {
           tonic::Status::not_found("wallet address not found")
         }
       })?;
 
     let transformed_devices = devices_map
       .into_iter()
       .filter_map(|(key, device_info)| {
         let device_info_with_auth = DeviceInfoWithAuth {
           device_info,
           auth_type: &auth_type,
         };
         match OutboundKeyInfo::try_from(device_info_with_auth) {
           Ok(key_info) => Some((key, key_info)),
           Err(_) => {
             error!("Failed to transform device info for key {}", key);
             None
           }
         }
       })
       .collect::<HashMap<_, _>>();
 
     Ok(tonic::Response::new(OutboundKeysForUserResponse {
       devices: transformed_devices,
     }))
   }
 
   async fn get_inbound_keys_for_user(
     &self,
     request: tonic::Request<InboundKeysForUserRequest>,
   ) -> Result<tonic::Response<InboundKeysForUserResponse>, tonic::Status> {
     let message = request.into_inner();
 
     use inbound_keys_for_user_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 devices_map = self
       .client
       .get_keys_for_user(user_ident, &auth_type, false)
       .await
       .map_err(handle_db_error)?
       .ok_or_else(|| match auth_type {
         AuthType::Password => tonic::Status::not_found("username not found"),
         AuthType::Wallet => {
           tonic::Status::not_found("wallet address not found")
         }
       })?;
 
     let transformed_devices = devices_map
       .into_iter()
       .filter_map(|(key, device_info)| {
         let device_info_with_auth = DeviceInfoWithAuth {
           device_info,
           auth_type: &auth_type,
         };
         match InboundKeyInfo::try_from(device_info_with_auth) {
           Ok(key_info) => Some((key, key_info)),
           Err(_) => {
             error!("Failed to transform device info for key {}", key);
             None
           }
         }
       })
       .collect::<HashMap<_, _>>();
 
     Ok(tonic::Response::new(InboundKeysForUserResponse {
       devices: transformed_devices,
     }))
   }
 
   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.signing_public_key);
 
     let token_valid = self
       .client
       .verify_access_token(
         message.user_id,
         message.signing_public_key.clone(),
         message.access_token,
       )
       .await
       .map_err(handle_db_error)?;
 
     let response = Response::new(VerifyUserAccessTokenResponse { token_valid });
     debug!(
       "device {} was verified: {}",
       &message.signing_public_key, token_valid
     );
     Ok(response)
   }
 
   async fn add_reserved_usernames(
     &self,
     request: tonic::Request<AddReservedUsernamesRequest>,
   ) -> Result<tonic::Response<Empty>, tonic::Status> {
     let message = request.into_inner();
 
     let usernames = validate_add_reserved_usernames_message(
       &message.message,
       &message.signature,
     )?;
 
     let filtered_usernames = self
       .client
       .filter_out_taken_usernames(usernames)
       .await
       .map_err(handle_db_error)?;
 
     self
       .client
       .add_usernames_to_reserved_usernames_table(filtered_usernames)
       .await
       .map_err(handle_db_error)?;
 
     let response = Response::new(Empty {});
     Ok(response)
   }
 
   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)
   }
 
   async fn ping(
     &self,
     _request: tonic::Request<Empty>,
   ) -> Result<Response<Empty>, tonic::Status> {
     let response = Response::new(Empty {});
     Ok(response)
   }
 }
 
 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 insert_into_cache(&self, workflow: WorkflowInProgress) -> String {
+#[tonic::async_trait]
+pub trait CacheExt<T> {
+  async fn insert_with_uuid_key(&self, value: T) -> String;
+}
+
+#[tonic::async_trait]
+impl<T> CacheExt<T> for Cache<String, T>
+where
+  T: Clone + Send + Sync + 'static,
+{
+  async fn insert_with_uuid_key(&self, value: T) -> String {
     let session_id = generate_uuid();
-    self.cache.insert(session_id.clone(), workflow).await;
+    self.insert(session_id.clone(), value).await;
     session_id
   }
 }
 
 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")
     }
     e => {
       error!("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,
 ) -> Result<UserRegistrationInfo, tonic::Status> {
   Ok(UserRegistrationInfo {
     username,
     flattened_device_key_upload: construct_flattened_device_key_upload(
       message,
     )?,
     user_id,
   })
 }
 
 fn construct_user_login_info(
   message: &impl DeviceKeyUploadActions,
   user_id: String,
   opaque_server_login: comm_opaque2::server::Login,
 ) -> Result<UserLoginInfo, tonic::Status> {
   Ok(UserLoginInfo {
     user_id,
     flattened_device_key_upload: construct_flattened_device_key_upload(
       message,
     )?,
     opaque_server_login,
   })
 }
 
 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)
 }