diff --git a/packages/simplexmq/lib/src/crypto.dart b/packages/simplexmq/lib/src/crypto.dart
index 46fa8943a9..bc00093efb 100644
--- a/packages/simplexmq/lib/src/crypto.dart
+++ b/packages/simplexmq/lib/src/crypto.dart
@@ -6,9 +6,12 @@ import 'package:pointycastle/asymmetric/oaep.dart';
 import 'package:pointycastle/asymmetric/rsa.dart';
 import 'package:pointycastle/block/aes_fast.dart';
 import 'package:pointycastle/block/modes/gcm.dart';
+import 'package:pointycastle/digests/sha256.dart';
 import 'package:pointycastle/key_generators/api.dart';
 import 'package:pointycastle/key_generators/rsa_key_generator.dart';
 import 'package:pointycastle/random/fortuna_random.dart';
+import 'package:pointycastle/signers/rsa_signer.dart';
+import 'buffer.dart' show empty;
 
 class AESKey {
   final Uint8List _key;
@@ -44,7 +47,6 @@ Uint8List _randomBytes(int len, Random seedSource) {
   return bytes;
 }
 
-final empty = Uint8List(0);
 final paddingByte = '#'.codeUnitAt(0);
 
 Uint8List encryptAES(AESKey key, Uint8List iv, int padTo, Uint8List data) {
@@ -90,3 +92,19 @@ Uint8List decryptOAEP(RSAPrivateKey key, Uint8List data) {
     ..init(false, PrivateKeyParameter<RSAPrivateKey>(key));
   return oaep.process(data);
 }
+
+Uint8List signPSS(RSAPrivateKey privateKey, Uint8List data) {
+  final signer = RSASigner(SHA256Digest(), '0609608648016503040201')
+    ..init(true, PrivateKeyParameter<RSAPrivateKey>(privateKey));
+  return signer.generateSignature(data).bytes;
+}
+
+bool verifyPSS(RSAPublicKey publicKey, Uint8List data, Uint8List sig) {
+  final verifier = RSASigner(SHA256Digest(), '0609608648016503040201')
+    ..init(false, PublicKeyParameter<RSAPublicKey>(publicKey));
+  try {
+    return verifier.verifySignature(data, RSASignature(sig));
+  } on ArgumentError {
+    return false;
+  }
+}
diff --git a/packages/simplexmq/lib/src/parser.dart b/packages/simplexmq/lib/src/parser.dart
index 18374e1825..752187bc26 100644
--- a/packages/simplexmq/lib/src/parser.dart
+++ b/packages/simplexmq/lib/src/parser.dart
@@ -17,6 +17,7 @@ final charDot = cc('.');
 
 class Parser {
   final Uint8List _s;
+  final List<int> _positions = [];
   int _pos = 0;
   bool _fail = false;
   Parser(this._s);
@@ -35,6 +36,20 @@ class Parser {
     return res;
   }
 
+  T? tryParse<T>(T? Function(Parser p) parse) {
+    if (_fail || _pos >= _s.length) {
+      _fail = true;
+      return null;
+    }
+    _positions.add(_pos);
+    final res = parse(this);
+    final prevPos = _positions.removeLast();
+    if (res == null) {
+      _pos = prevPos;
+      _fail = false;
+    }
+  }
+
   // takes a required number of bytes
   Uint8List? take(int len) => _run(() {
         final end = _pos + len;
diff --git a/packages/simplexmq/lib/src/protocol.dart b/packages/simplexmq/lib/src/protocol.dart
index 2e90d76847..f80b88d97d 100644
--- a/packages/simplexmq/lib/src/protocol.dart
+++ b/packages/simplexmq/lib/src/protocol.dart
@@ -174,7 +174,7 @@ class ERR extends BrokerCommand {
       : cmdErr = err == ErrorType.CMD
             ? throw ArgumentError('CMD error should be created with ERR.CMD')
             : null;
-  ERR.cmd(this.cmdErr) : err = ErrorType.CMD;
+  ERR.cmd(CmdErrorType this.cmdErr) : err = ErrorType.CMD;
   @override
   Uint8List serialize() {
     final _err = errorTags[err]!;
diff --git a/packages/simplexmq/lib/src/transport.dart b/packages/simplexmq/lib/src/transport.dart
index 87240ad203..baf6cf9a41 100644
--- a/packages/simplexmq/lib/src/transport.dart
+++ b/packages/simplexmq/lib/src/transport.dart
@@ -5,6 +5,7 @@ import 'package:pointycastle/digests/sha256.dart';
 import 'buffer.dart';
 import 'crypto.dart';
 import 'parser.dart';
+import 'protocol.dart';
 import 'rsa_keys.dart';
 
 abstract class Transport {
@@ -13,16 +14,6 @@ abstract class Transport {
   Future<void> close();
 }
 
-Stream<Uint8List> blockStream(Transport t, int blockSize) async* {
-  try {
-    while (true) {
-      yield await t.read(blockSize);
-    }
-  } catch (e) {
-    return;
-  }
-}
-
 class SMPServer {
   final String host;
   final int? port;
@@ -59,11 +50,63 @@ const int _binaryRsaTransport = 0;
 const int _transportBlockSize = 4096;
 const int _maxTransportBlockSize = 65536;
 
+class _Request {
+  final Uint8List queueId;
+  final Completer<BrokerResponse> completer = Completer();
+  _Request(this.queueId);
+}
+
+class Either<L, R> {
+  final L? left;
+  final R? right;
+  Either.left(L this.left) : right = null;
+  Either.right(R this.right) : left = null;
+}
+
+enum ClientErrorType { SMPServerError, SMPResponseError, SMPUnexpectedResponse }
+
+class BrokerResponse {
+  final BrokerCommand? command;
+  final ClientErrorType? errorType;
+  final ERR? error;
+  BrokerResponse(BrokerCommand this.command)
+      : errorType = null,
+        error = null;
+  BrokerResponse.error(ClientErrorType this.errorType, this.error)
+      : command = null;
+}
+
+class ClientTransmission {
+  final String corrId;
+  final Uint8List queueId;
+  final ClientCommand command;
+  ClientTransmission(this.corrId, this.queueId, this.command);
+
+  Uint8List serialize() =>
+      unwordsN([encodeAscii(corrId), encode64(queueId), command.serialize()]);
+}
+
+class BrokerTransmission {
+  final String corrId;
+  final Uint8List queueId;
+  final BrokerCommand? command;
+  final ERR? error;
+  BrokerTransmission(this.corrId, this.queueId, BrokerCommand this.command)
+      : error = null;
+  BrokerTransmission.error(this.corrId, this.queueId, ERR this.error)
+      : command = null;
+}
+
+final badBlock = BrokerTransmission.error('', empty, ERR(ErrorType.BLOCK));
+
 class SMPTransportClient {
   final Transport _conn;
   final _sndKey = SessionKey.create();
   final _rcvKey = SessionKey.create();
   final int blockSize;
+  int _corrId = 0;
+  bool _messageStreamCreated = false;
+  final Map<String, _Request> _sentCommands = {};
   SMPTransportClient._(this._conn, this.blockSize);
 
   static Future<SMPTransportClient> connect(Transport conn,
@@ -75,6 +118,92 @@ class SMPTransportClient {
     return _conn.close();
   }
 
+  Future<BrokerResponse> sendSMPCommand(
+      RSAPrivateKey? key, Uint8List queueId, ClientCommand cmd) async {
+    final corrId = (++_corrId).toString();
+    final t = ClientTransmission(corrId, queueId, cmd).serialize();
+    final sig = key == null ? empty : encode64(signPSS(key, t));
+    final data = unwordsN([sig, t, empty]);
+    final r = _sentCommands[corrId] = _Request(queueId);
+    await _writeEncrypted(data);
+    print('block sent');
+    return r.completer.future;
+  }
+
+  Stream<BrokerTransmission> messageStream() {
+    if (_messageStreamCreated) {
+      throw Exception('message stream already created');
+    }
+    _messageStreamCreated = true;
+    return _messageStream();
+  }
+
+  Stream<BrokerTransmission> _messageStream() async* {
+    try {
+      while (true) {
+        final block = await _readEncrypted();
+        final t = _parseBrokerTransmission(block);
+        print('block received');
+        print(t);
+        if (t.corrId == '') {
+          yield t;
+        } else {
+          final r = _sentCommands.remove(t.corrId);
+          if (r == null) {
+            yield t;
+          } else {
+            final cmd = t.command;
+            r.completer.complete(r.queueId.equal(t.queueId)
+                ? cmd == null
+                    ? BrokerResponse.error(
+                        ClientErrorType.SMPResponseError, t.error)
+                    : cmd is ERR
+                        ? BrokerResponse.error(
+                            ClientErrorType.SMPServerError, cmd)
+                        : BrokerResponse(cmd)
+                : BrokerResponse.error(
+                    ClientErrorType.SMPUnexpectedResponse, null));
+          }
+        }
+      }
+    } catch (e) {
+      return;
+    }
+  }
+
+  static BrokerTransmission _parseBrokerTransmission(Uint8List s) {
+    final p = Parser(s);
+    p.space();
+    final cId = p.word();
+    p.space();
+    final queueId = p.tryParse((p) => p.base64()) ?? empty;
+    p.space();
+    if (p.fail || cId == null) return badBlock;
+    final corrId = decodeAscii(cId);
+    final command = smpCommandP(p);
+    if (command == null) {
+      return BrokerTransmission.error(
+          corrId, queueId, ERR.cmd(CmdErrorType.SYNTAX));
+    }
+    if (command is! BrokerCommand) {
+      return BrokerTransmission.error(
+          corrId, queueId, ERR.cmd(CmdErrorType.PROHIBITED));
+    }
+    final qErr = _tQueueError(queueId, command);
+    if (qErr != null) {
+      return BrokerTransmission.error(corrId, queueId, ERR.cmd(qErr));
+    }
+    return BrokerTransmission(corrId, queueId, command);
+  }
+
+  static CmdErrorType? _tQueueError(Uint8List queueId, BrokerCommand cmd) {
+    if (cmd is IDS || cmd is PONG) {
+      if (queueId.isNotEmpty) return CmdErrorType.HAS_AUTH;
+    } else if (cmd is! ERR && queueId.isEmpty) {
+      return CmdErrorType.NO_QUEUE;
+    }
+  }
+
   static Future<SMPTransportClient> _clientHandshake(
       Transport conn, Uint8List? keyHash, int? blkSize) async {
     final srv = await _getHeaderAndPublicKey_1_2(conn, keyHash);
@@ -166,6 +295,12 @@ class SMPTransportClient {
     return decryptAES(_rcvKey.aesKey, iv, block);
   }
 
+  Future<void> _writeEncrypted(Uint8List data) {
+    final iv = _nextIV(_sndKey);
+    final block = encryptAES(_sndKey.aesKey, iv, blockSize, data);
+    return _conn.write(block);
+  }
+
   static Uint8List _nextIV(SessionKey sk) {
     final c = encodeInt32(sk._counter++);
     final start = sk.baseIV.sublist(0, 4);
diff --git a/packages/simplexmq_io/test/transport_test.dart b/packages/simplexmq_io/test/transport_test.dart
index a9ba0db785..3b46e0edc9 100644
--- a/packages/simplexmq_io/test/transport_test.dart
+++ b/packages/simplexmq_io/test/transport_test.dart
@@ -1,21 +1,37 @@
-// import 'dart:io';
 import 'package:simplexmq/simplexmq.dart';
 import 'package:simplexmq/src/buffer.dart';
+import 'package:simplexmq/src/crypto.dart';
+import 'package:simplexmq/src/rsa_keys.dart';
 import 'package:simplexmq_io/simplexmq_io.dart';
 import 'package:test/test.dart';
 
+final keyHash =
+    decode64(encodeAscii('pH7bg7B6vB3uJ1poKmClTAqr7yYWnAtapnIDN7ypKxU='));
 void main() {
-  group('SMP transport', () {
-    test(
-      'establish connection (expects SMP server on localhost:5223)',
-      () async {
-        final conn = await SocketTransport.connect('localhost', 5223);
-        final smp = await SMPTransportClient.connect(conn,
-            keyHash: decode64(
-                encodeAscii('pH7bg7B6vB3uJ1poKmClTAqr7yYWnAtapnIDN7ypKxU=')));
-        expect(smp is SMPTransportClient, true);
-      },
-      skip: 'requires SMP server on port 5223',
-    );
-  });
+  group('SMP transport (expects SMP server on localhost:5223)', () {
+    test('establish connection', () async {
+      final conn = await SocketTransport.connect('localhost', 5223);
+      final smp = await SMPTransportClient.connect(conn, keyHash: keyHash);
+      expect(smp is SMPTransportClient, true);
+    });
+
+    test('should create SMP queue and send message', () async {
+      final conn1 = await SocketTransport.connect('localhost', 5223);
+      final alice = await SMPTransportClient.connect(conn1, keyHash: keyHash);
+      final aliceKeys = generateRSAkeyPair();
+      final rcvKeyStr = encode64(encodeRsaPubKey(aliceKeys.publicKey));
+
+      // final conn2 = await SocketTransport.connect('localhost', 5223);
+      // final bob = await SMPTransportClient.connect(conn2, keyHash: keyHash);
+      // final bobKeys = generateRSAkeyPair();
+      // final sndKeyStr = encode64(encodeRsaPubKey(bobKeys.publicKey));
+
+      // print('we are here');
+
+      final resp = await alice.sendSMPCommand(
+          aliceKeys.privateKey, empty, NEW(rcvKeyStr));
+      print(resp);
+    });
+    // });
+  }, skip: 'requires SMP server on port 5223');
 }