diff --git a/core/src/miner/stratum.rs b/core/src/miner/stratum.rs
index 11ad73a4c6..3cd18b6a7b 100644
--- a/core/src/miner/stratum.rs
+++ b/core/src/miner/stratum.rs
@@ -19,6 +19,7 @@
 use std::net::{AddrParseError, SocketAddr};
 use std::sync::Arc;
 
+use super::super::error::Error as MinerError;
 use cstratum::{Error as StratumServiceError, JobDispatcher, PushWorkHandler, Stratum as StratumService};
 use primitives::{Bytes, H256, U256};
 
@@ -56,14 +57,14 @@ impl JobDispatcher for StratumJobDispatcher {
 
         if !self.miner.can_produce_work_package() {
             cwarn!(STRATUM, "Cannot get work package - engine seals internally.");
-            return Err(StratumServiceError::NoWork)
+            return Err(StratumServiceError::InternalError)
         }
 
         match self.miner.submit_seal(&*self.client, pow_hash, seal) {
             Ok(_) => Ok(()),
             Err(e) => {
                 cwarn!(STRATUM, "submit_seal error: {:?}", e);
-                Err(StratumServiceError::Dispatch(e.to_string()))
+                Err(StratumServiceError::from(e))
             }
         }
     }
@@ -98,6 +99,16 @@ pub enum Error {
     Address(AddrParseError),
 }
 
+impl From<MinerError> for StratumServiceError {
+    fn from(err: MinerError) -> Self {
+        match err {
+            MinerError::PowHashInvalid => StratumServiceError::PowHashInvalid,
+            MinerError::PowInvalid => StratumServiceError::PowInvalid,
+            _ => StratumServiceError::InternalError,
+        }
+    }
+}
+
 impl From<StratumServiceError> for Error {
     fn from(service_err: StratumServiceError) -> Error {
         Error::Service(service_err)
diff --git a/spec/Stratum.md b/spec/Stratum.md
index 146d879f2f..7e84bde05a 100644
--- a/spec/Stratum.md
+++ b/spec/Stratum.md
@@ -101,7 +101,7 @@ Params:
  1. powHash: `string`
  2. seal: `string[]`
 
-Return Type: `bool`
+Return Type: `null`
 
 Request Example
 ```
@@ -118,27 +118,24 @@ Response Example
 {
     "jsonrpc": "2.0",
     "id": 4,
-    "result": true,
+    "result": null,
     "error": null
 }
 ```
 
-## Exception Handling (DRAFT)
+## Exception Handling
 Stratum defines simple exception handling. Example of a rejected share looks like:
 ```
 {
     "jsonrpc": "2.0",
     "id": 5,
-    "result": null,
-    "error": (21, "Job not found", null)
+    "error": {"code":21, "message":"Invalid Pow hash"}
 }
 ```
 
-Where the error field is defined as (error_code, human_readable_message, traceback). Traceback may contain additional information about debugging errors.
+Where the error field is defined as (error_code, human_readable_message).
 Proposed error codes for mining services are:
-* 20 - Other/Unknown
-* 21 - Job not found (=stale)
-* 22 - Duplicate share
-* 23 - Low target share
-* 24 - Unauthorized worker
-* 25 - Not subscribed
+* 20 - Internal Error
+* 21 - Invalid Pow hash (=stale)
+* 22 - Invalid the nonce
+* 23 - Unauthorized worker
diff --git a/stratum/src/lib.rs b/stratum/src/lib.rs
index fb7b4546a5..af1565fea7 100644
--- a/stratum/src/lib.rs
+++ b/stratum/src/lib.rs
@@ -181,22 +181,24 @@ impl StratumImpl {
 
     /// rpc method `mining.submit`
     fn submit(&self, params: Params, meta: SocketMetadata) -> RpcResult {
-        params
-            .parse::<(H256, Vec<String>)>()
-            .map(|(pow_hash, seal)| {
-                let seal = seal.iter().cloned().map(Into::into).collect();
-                match self.dispatcher.submit((pow_hash, seal)) {
-                    Ok(()) => {
-                        self.update_peers(&meta.tcp_dispatcher.expect("tcp_dispatcher is always initialized"));
-                        to_value(true)
-                    }
-                    Err(submit_err) => {
-                        cwarn!(STRATUM, "Error while submitting share: {:?}", submit_err);
-                        to_value(false)
-                    }
+        let workers = self.workers.read();
+        if workers.contains_key(&meta.addr) == false {
+            return Err(Error::UnauthorizedWorker.into())
+        }
+
+        params.parse::<(H256, Vec<String>)>().and_then(|(pow_hash, seal)| {
+            let seal = seal.iter().cloned().map(Into::into).collect();
+            match self.dispatcher.submit((pow_hash, seal)) {
+                Ok(()) => {
+                    self.update_peers(&meta.tcp_dispatcher.expect("tcp_dispatcher is always initialized"));
+                    Ok(jsonrpc_core::Value::Null)
                 }
-            })
-            .map(|v| v.expect("Only true/false is returned and it's always serializable"))
+                Err(submit_err) => {
+                    cwarn!(STRATUM, "Error while submitting share: {:?}", submit_err);
+                    Err(submit_err.into())
+                }
+            }
+        })
     }
 
     /// Helper method
@@ -524,6 +526,36 @@ mod tests {
 
         let response = String::from_utf8(core.run(stream).expect("Core should run with no errors"))
             .expect("Response should be utf-8");
-        assert_eq!("{\"jsonrpc\":\"2.0\",\"result\":true,\"id\":2}\n", response);
+        assert_eq!("{\"jsonrpc\":\"2.0\",\"result\":null,\"id\":2}\n", response);
+    }
+
+    #[test]
+    fn should_return_error_when_unauthorized_worker_submits() {
+        let addr = SocketAddr::from_str("127.0.0.1:19991").unwrap();
+        let _stratum =
+            Stratum::start(&addr, Arc::new(DummyManager::build().of_initial(r#"["dummy authorize payload"]"#)), None)
+                .expect("There should be no error starting stratum");
+
+        let mut submit_request =
+            r#"{"jsonrpc": "2.0", "method": "mining.submit", "params": ["0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef", ["0x56642f04d519ae3262c7ba6facf1c5b11450ebaeb7955337cfbc45420d573077"]], "id": 2}"#.as_bytes()
+                .to_vec();
+        submit_request.extend(b"\n");
+
+        let mut core = Core::new().expect("Tokio Core should be created with no errors");
+        let mut buffer = vec![0u8; 2048];
+        let stream = TcpStream::connect(&addr, &core.handle())
+            .and_then(|stream| io::write_all(stream, &submit_request))
+            .and_then(|(stream, _)| io::read(stream, &mut buffer))
+            .and_then(|(_, read_buf, len)| {
+                ctrace!(STRATUM, "Received result from server");
+                future::ok(read_buf[0..len].to_vec())
+            });
+
+        let response = String::from_utf8(core.run(stream).expect("Core should run with no errors"))
+            .expect("Response should be utf-8");
+        assert_eq!(
+            "{\"jsonrpc\":\"2.0\",\"error\":{\"code\":23,\"message\":\"Unauthorized worker\"},\"id\":2}\n",
+            response
+        );
     }
 }
diff --git a/stratum/src/traits.rs b/stratum/src/traits.rs
index 9bf40bb867..016db419e4 100644
--- a/stratum/src/traits.rs
+++ b/stratum/src/traits.rs
@@ -17,16 +17,20 @@
 use std;
 use std::error::Error as StdError;
 
+use jsonrpc_core::{Error as JsonError, ErrorCode as JsonErrorCode};
 use jsonrpc_tcp_server::PushMessageError;
 use primitives::{Bytes, H256};
 
 #[derive(Debug, Clone)]
 pub enum Error {
+    InternalError,
+    PowHashInvalid,
+    PowInvalid,
+    UnauthorizedWorker,
     NoWork,
     NoWorkers,
     Io(String),
     Tcp(String),
-    Dispatch(String),
 }
 
 impl From<std::io::Error> for Error {
@@ -41,6 +45,23 @@ impl From<PushMessageError> for Error {
     }
 }
 
+impl Into<JsonError> for Error {
+    fn into(self) -> JsonError {
+        let (code, message) = match self {
+            Error::PowHashInvalid => (21, format!("Invalid Pow hash")),
+            Error::PowInvalid => (22, format!("Invalid the nonce")),
+            Error::UnauthorizedWorker => (23, format!("Unauthorized worker")),
+            _ => (20, format!("Internal error")),
+        };
+
+        JsonError {
+            code: JsonErrorCode::ServerError(code),
+            message,
+            data: None,
+        }
+    }
+}
+
 /// Interface that can provide pow/blockchain-specific responses for the clients
 pub trait JobDispatcher: Send + Sync {
     // json for initial client handshake