diff --git a/native/cpp/CommonCpp/grpc/grpc_client/src/lib.rs b/native/cpp/CommonCpp/grpc/grpc_client/src/lib.rs
index f382b2647..335cdf432 100644
--- a/native/cpp/CommonCpp/grpc/grpc_client/src/lib.rs
+++ b/native/cpp/CommonCpp/grpc/grpc_client/src/lib.rs
@@ -1,375 +1,380 @@
 use lazy_static::lazy_static;
 use opaque_ke::{
   ClientLogin, ClientLoginFinishParameters, ClientLoginStartParameters,
   ClientLoginStartResult, ClientRegistration,
   ClientRegistrationFinishParameters, CredentialFinalization,
   CredentialResponse, RegistrationResponse, RegistrationUpload,
 };
 use rand::{rngs::OsRng, CryptoRng, Rng};
 use std::sync::Arc;
 use tokio::runtime::{Builder, Runtime};
 use tokio::sync::mpsc;
 use tokio_stream::wrappers::ReceiverStream;
 use tonic::{transport::Channel, Request, Response, Status};
 use tracing::{error, instrument};
 
 use ::identity::Cipher;
 
 use crate::identity::{
   get_user_id_request::AuthType,
   identity_service_client::IdentityServiceClient,
   pake_login_response::Data::AccessToken,
   pake_login_response::Data::PakeCredentialResponse,
   registration_request::Data::PakeCredentialFinalization,
   registration_request::Data::PakeRegistrationRequestAndUserId,
   registration_request::Data::PakeRegistrationUploadAndCredentialRequest,
   registration_response::Data::PakeLoginResponse,
   registration_response::Data::PakeRegistrationResponse, GetUserIdRequest,
   GetUserIdResponse, LoginRequest, LoginResponse,
   PakeLoginResponse as PakeLoginResponseStruct,
   PakeRegistrationRequestAndUserId as PakeRegistrationRequestAndUserIdStruct,
   PakeRegistrationUploadAndCredentialRequest as PakeRegistrationUploadAndCredentialRequestStruct,
   RegistrationRequest, RegistrationResponse as RegistrationResponseMessage,
   VerifyUserTokenRequest, VerifyUserTokenResponse,
 };
 pub mod identity {
   tonic::include_proto!("identity");
 }
 
 const IDENTITY_SERVICE_SOCKET_ADDR: &str = "https://[::1]:50051";
 
 lazy_static! {
   pub static ref RUNTIME: Arc<Runtime> = Arc::new(
     Builder::new_multi_thread()
       .worker_threads(1)
       .max_blocking_threads(1)
       .enable_all()
       .build()
       .unwrap()
   );
 }
 
 #[cxx::bridge(namespace = "identity")]
 mod ffi {}
 
 pub struct Client {
   identity_client: IdentityServiceClient<Channel>,
 }
 
 impl Client {
   async fn new() -> Self {
     Self {
       identity_client: IdentityServiceClient::connect(
         IDENTITY_SERVICE_SOCKET_ADDR,
       )
       .await
       .unwrap(),
     }
   }
 
   async fn get_user_id(
     &mut self,
     auth_type: AuthType,
     user_info: String,
   ) -> Result<Response<GetUserIdResponse>, Status> {
     self
       .identity_client
       .get_user_id(GetUserIdRequest {
         auth_type: auth_type.into(),
         user_info,
       })
       .await
   }
 
   #[instrument(skip(self))]
   fn get_user_id_blocking(
     &mut self,
     auth_type: AuthType,
     user_info: String,
   ) -> Result<Response<GetUserIdResponse>, Status> {
     RUNTIME.block_on(self.get_user_id(auth_type, user_info))
   }
 
   #[instrument(skip(self))]
   async fn verify_user_token(
     &mut self,
     user_id: String,
     device_id: String,
     access_token: String,
   ) -> Result<Response<VerifyUserTokenResponse>, Status> {
     self
       .identity_client
       .verify_user_token(VerifyUserTokenRequest {
         user_id,
         device_id,
         access_token,
       })
       .await
   }
 
   #[instrument(skip(self))]
   async fn register_user(
     &mut self,
     user_id: String,
     device_id: String,
     username: String,
     password: String,
     user_public_key: String,
   ) -> Result<String, Status> {
     // Create a RegistrationRequest channel and use ReceiverStream to turn the
     // MPSC receiver into a Stream for outbound messages
     let (tx, rx) = mpsc::channel(1);
     let stream = ReceiverStream::new(rx);
     let request = Request::new(stream);
 
     // `response` is the Stream for inbound messages
     let mut response = self
       .identity_client
       .register_user(request)
       .await?
       .into_inner();
 
     // Start PAKE registration on client and send initial registration request
     // to Identity service
     let mut client_rng = OsRng;
     let (registration_request, client_registration) = pake_registration_start(
       &mut client_rng,
       user_id,
       &password,
       device_id,
       username,
       user_public_key,
     )?;
     if let Err(e) = tx.send(registration_request).await {
       error!("Response was dropped: {}", e);
       return Err(Status::aborted("Dropped response"));
     }
 
     // Handle responses from Identity service sequentially, making sure we get
     // messages in the correct order
 
     // Finish PAKE registration and begin PAKE login; send the final
     // registration request and initial login request together to reduce the
     // number of trips
     let message = response.message().await?;
     let client_login = handle_registration_response(
       message,
       &mut client_rng,
       client_registration,
       &password,
       tx.clone(),
     )
     .await?;
 
     // Finish PAKE login; send final login request to Identity service
     let message = response.message().await?;
     handle_credential_response(message, client_login, tx).await?;
 
     // Return access token
     let message = response.message().await?;
     handle_token_response(message)
   }
 }
 
 fn pake_registration_start(
   rng: &mut (impl Rng + CryptoRng),
   user_id: String,
   password: &str,
   device_id: String,
   username: String,
   user_public_key: String,
 ) -> Result<(RegistrationRequest, ClientRegistration<Cipher>), Status> {
   let client_registration_start_result =
     ClientRegistration::<Cipher>::start(rng, password.as_bytes()).map_err(
       |e| {
         error!("Failed to start PAKE registration: {}", e);
         Status::failed_precondition("PAKE failure")
       },
     )?;
   let pake_registration_request =
     client_registration_start_result.message.serialize();
   Ok((
     RegistrationRequest {
       data: Some(PakeRegistrationRequestAndUserId(
         PakeRegistrationRequestAndUserIdStruct {
           user_id,
           device_id,
           pake_registration_request,
           username,
           user_public_key,
         },
       )),
     },
     client_registration_start_result.state,
   ))
 }
 
 fn pake_registration_finish(
   rng: &mut (impl Rng + CryptoRng),
   registration_response_bytes: &[u8],
   client_registration: ClientRegistration<Cipher>,
 ) -> Result<RegistrationUpload<Cipher>, Status> {
   client_registration
     .finish(
       rng,
       RegistrationResponse::deserialize(registration_response_bytes).map_err(
         |e| {
           error!("Could not deserialize registration response bytes: {}", e);
           Status::aborted("Invalid response bytes")
         },
       )?,
       ClientRegistrationFinishParameters::default(),
     )
     .map_err(|e| {
       error!("Failed to finish PAKE registration: {}", e);
       Status::aborted("PAKE failure")
     })
     .map(|res| res.message)
 }
 
 fn pake_login_start(
   rng: &mut (impl Rng + CryptoRng),
   password: &str,
 ) -> Result<ClientLoginStartResult<Cipher>, Status> {
   ClientLogin::<Cipher>::start(
     rng,
     password.as_bytes(),
     ClientLoginStartParameters::default(),
   )
   .map_err(|e| {
     error!("Failed to start PAKE login: {}", e);
     Status::failed_precondition("PAKE failure")
   })
 }
 
 fn pake_login_finish(
   credential_response_bytes: &[u8],
   client_login: ClientLogin<Cipher>,
 ) -> Result<CredentialFinalization<Cipher>, Status> {
   client_login
     .finish(
       CredentialResponse::deserialize(credential_response_bytes).map_err(
         |e| {
           error!("Could not deserialize credential response bytes: {}", e);
           Status::aborted("Invalid response bytes")
         },
       )?,
       ClientLoginFinishParameters::default(),
     )
     .map_err(|e| {
       error!("Failed to finish PAKE login: {}", e);
       Status::aborted("PAKE failure")
     })
     .map(|res| res.message)
 }
 
 fn handle_unexpected_registration_response(
   message: Option<RegistrationResponseMessage>,
 ) -> Status {
   error!("Received an unexpected message: {:?}", message);
   Status::invalid_argument("Invalid response data")
 }
 
 async fn handle_registration_response(
   message: Option<RegistrationResponseMessage>,
   client_rng: &mut (impl Rng + CryptoRng),
   client_registration: ClientRegistration<Cipher>,
   password: &str,
   tx: mpsc::Sender<RegistrationRequest>,
 ) -> Result<ClientLogin<Cipher>, Status> {
   if let Some(RegistrationResponseMessage {
     data: Some(PakeRegistrationResponse(registration_response_bytes)),
     ..
   }) = message
   {
     let pake_registration_upload = pake_registration_finish(
       client_rng,
       &registration_response_bytes,
       client_registration,
     )?
     .serialize();
     let client_login_start_result = pake_login_start(client_rng, password)?;
 
     // `registration_request` is a gRPC message containing serialized bytes to
     // complete PAKE registration and begin PAKE login
     let registration_request = RegistrationRequest {
       data: Some(PakeRegistrationUploadAndCredentialRequest(
         PakeRegistrationUploadAndCredentialRequestStruct {
           pake_registration_upload,
           pake_credential_request: client_login_start_result
             .message
             .serialize()
             .map_err(|e| {
               error!("Could not serialize credential request: {}", e);
               Status::failed_precondition("PAKE failure")
             })?,
         },
       )),
     };
     if let Err(e) = tx.send(registration_request).await {
       error!("Response was dropped: {}", e);
       return Err(Status::aborted("Dropped response"));
     }
     Ok(client_login_start_result.state)
   } else {
     Err(handle_unexpected_registration_response(message))
   }
 }
 
 async fn handle_credential_response(
   message: Option<RegistrationResponseMessage>,
   client_login: ClientLogin<Cipher>,
   tx: mpsc::Sender<RegistrationRequest>,
 ) -> Result<(), Status> {
   if let Some(RegistrationResponseMessage {
     data:
       Some(PakeLoginResponse(PakeLoginResponseStruct {
         data: Some(PakeCredentialResponse(credential_response_bytes)),
       })),
   }) = message
   {
     let registration_request = RegistrationRequest {
       data: Some(PakeCredentialFinalization(
         pake_login_finish(&credential_response_bytes, client_login)?
           .serialize()
           .map_err(|e| {
             error!("Could not serialize credential request: {}", e);
             Status::failed_precondition("PAKE failure")
           })?,
       )),
     };
     if let Err(e) = tx.send(registration_request).await {
       error!("Response was dropped: {}", e);
       return Err(Status::aborted("Dropped response"));
     }
     Ok(())
   } else {
     Err(handle_unexpected_registration_response(message))
   }
 }
 
 fn handle_token_response(
   message: Option<RegistrationResponseMessage>,
 ) -> Result<String, Status> {
   if let Some(RegistrationResponseMessage {
     data:
       Some(PakeLoginResponse(PakeLoginResponseStruct {
         data: Some(AccessToken(access_token)),
       })),
   }) = message
   {
     Ok(access_token)
   } else {
     Err(handle_unexpected_registration_response(message))
   }
 }
 
 struct RegistrationResponseAndSender {
   response: Option<RegistrationResponseMessage>,
   sender: mpsc::Sender<RegistrationRequest>,
 }
 
 struct LoginResponseAndSender {
   response: Option<LoginResponse>,
   sender: mpsc::Sender<LoginRequest>,
 }
+
+enum ResponseAndSender {
+  Registration(RegistrationResponseAndSender),
+  Login(LoginResponseAndSender),
+}