diff --git a/native/cpp/CommonCpp/grpc/protos/identity.proto b/native/cpp/CommonCpp/grpc/protos/identity.proto
--- a/native/cpp/CommonCpp/grpc/protos/identity.proto
+++ b/native/cpp/CommonCpp/grpc/protos/identity.proto
@@ -11,6 +11,9 @@
   // Called by other services to verify a user's token
   rpc VerifyUserToken(VerifyUserTokenRequest) returns (VerifyUserTokenResponse)
     {}
+  // Called by users and keyservers to get userID corresponding to a wallet
+  // address or username
+  rpc GetUserID(GetUserIDRequest) returns (GetUserIDResponse) {}
 }
 
 // Helper types
@@ -119,3 +122,18 @@
 message VerifyUserTokenResponse {
   bool tokenValid = 1;
 }
+
+// GetUserID
+
+message GetUserIDRequest {
+  enum AuthType {
+    PASSWORD = 0;
+    WALLET = 1;
+  }
+  AuthType authType = 1;
+  string userInfo = 2;
+}
+
+message GetUserIDResponse {
+  string userID = 1;
+}
diff --git a/services/identity/src/service.rs b/services/identity/src/service.rs
--- a/services/identity/src/service.rs
+++ b/services/identity/src/service.rs
@@ -38,8 +38,9 @@
   registration_request::Data::PakeRegistrationRequestAndUserId,
   registration_request::Data::PakeRegistrationUploadAndCredentialRequest,
   registration_response::Data::PakeLoginResponse as PakeRegistrationLoginResponse,
-  registration_response::Data::PakeRegistrationResponse, LoginRequest,
-  LoginResponse, PakeLoginRequest as PakeLoginRequestStruct,
+  registration_response::Data::PakeRegistrationResponse, GetUserIdRequest,
+  GetUserIdResponse, LoginRequest, LoginResponse,
+  PakeLoginRequest as PakeLoginRequestStruct,
   PakeLoginResponse as PakeLoginResponseStruct, RegistrationRequest,
   RegistrationResponse, VerifyUserTokenRequest, VerifyUserTokenResponse,
   WalletLoginRequest as WalletLoginRequestStruct,
@@ -342,6 +343,14 @@
     info!("Sending VerifyUserToken response: {:?}", response);
     Ok(response)
   }
+
+  #[instrument(skip(self))]
+  async fn get_user_id(
+    &self,
+    request: Request<GetUserIdRequest>,
+  ) -> Result<Response<GetUserIdResponse>, Status> {
+    unimplemented!();
+  }
 }
 
 async fn put_token_helper(