diff --git a/compliance/test_fuzzingclient.py b/compliance/test_fuzzingclient.py
index 038a2c6..63fc326 100644
--- a/compliance/test_fuzzingclient.py
+++ b/compliance/test_fuzzingclient.py
@@ -3,6 +3,11 @@
 import websocket
 import json
 import traceback
+import six
+
+
+
+
 
 SERVER = 'ws://127.0.0.1:8642'
 AGENT = 'py-websockets-cleint'
@@ -30,8 +35,8 @@ for case in range(1, count+1):
 		success += 1
 	except Exception as e:
 		failed += 1
-		print("[Faield] Test Case: " + str(case))
-		print(traceback.format_exc())
+		# print("[Faield] Test Case: " + str(case))
+		#print(traceback.format_exc())
 	finally:
 		ws.close()
 
diff --git a/websocket/_core.py b/websocket/_core.py
index ef1247f..a0ffc37 100644
--- a/websocket/_core.py
+++ b/websocket/_core.py
@@ -57,7 +57,7 @@ import logging
 # websocket modules
 from ._exceptions import *
 from ._abnf import ABNF
-from ._utils import NoLock
+from ._utils import NoLock, validate_utf8
 
 """
 websocket python client.
@@ -732,6 +732,8 @@ class WebSocket(object):
                     data = self._cont_data
                     self._cont_data = None
                     frame.data = data[1]
+                    if not self.fire_cont_frame and data[0] == ABNF.OPCODE_TEXT and not validate_utf8(frame.data):
+                        raise UnicodeDecodeError("cannot decode: " + repr(frame.data))
                     return [data[0], frame]
 
             elif frame.opcode == ABNF.OPCODE_CLOSE:
diff --git a/websocket/_utils.py b/websocket/_utils.py
index c23bf6f..31f7d0c 100644
--- a/websocket/_utils.py
+++ b/websocket/_utils.py
@@ -19,6 +19,7 @@ Copyright (C) 2010 Hiroki Ohtani(liris)
 
 """
 
+import six
 
 class NoLock(object):
     def __enter__(self):
@@ -27,3 +28,57 @@ class NoLock(object):
     def __exit__(self,type, value, traceback):
         pass
 
+
+# UTF-8 validator
+# python implementation of http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
+
+UTF8_ACCEPT = 0
+UTF8_REJECT=12
+
+_UTF8D = [
+    # The first part of the table maps bytes to character classes that
+    # to reduce the size of the transition table and create bitmasks.
+    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+    1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,  9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
+    7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+    8,8,2,2,2,2,2,2,2,2,2,2,2,2,2,2,  2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
+    10,3,3,3,3,3,3,3,3,3,3,3,3,4,3,3, 11,6,6,6,5,8,8,8,8,8,8,8,8,8,8,8,
+
+    # The second part is a transition table that maps a combination
+    # of a state of the automaton and a character class to a state.
+    0,12,24,36,60,96,84,12,12,12,48,72, 12,12,12,12,12,12,12,12,12,12,12,12,
+    12, 0,12,12,12,12,12, 0,12, 0,12,12, 12,24,12,12,12,12,12,24,12,24,12,12,
+    12,12,12,12,12,12,12,24,12,12,12,12, 12,24,12,12,12,12,12,12,12,24,12,12,
+    12,12,12,12,12,12,12,36,12,36,12,12, 12,36,12,12,12,12,12,36,12,36,12,12,
+    12,36,12,12,12,12,12,12,12,12,12,12, ]
+
+def _decode(state, codep, ch):
+    tp = _UTF8D[ch]
+
+    codep = (ch & 0x3f ) | (codep << 6) if (state != UTF8_ACCEPT)  else (0xff >> tp) & (ch)
+    state = _UTF8D[256 + state + tp]
+
+    return state, codep;
+
+def validate_utf8(utfbytes):
+    """
+    validate utf8 byte string.
+    utfbytes: utf byte string to check.
+    return value: if valid utf8 string, return true. Otherwise, return false.
+    """
+    state = UTF8_ACCEPT
+    codep = 0
+    for i in utfbytes:
+        if six.PY2:
+            i = ord(i)
+        state, codep = _decode(state, codep, i)
+        if state == UTF8_REJECT:
+            return False
+
+    return True
+
+
+
diff --git a/websocket/tests/test_websocket.py b/websocket/tests/test_websocket.py
index 84ea5ca..eab6c47 100644
--- a/websocket/tests/test_websocket.py
+++ b/websocket/tests/test_websocket.py
@@ -25,6 +25,7 @@ import uuid
 # websocket-client
 import websocket as ws
 from websocket._core import _parse_url, _create_sec_websocket_key
+from websocket._utils import validate_utf8
 
 
 # Skip test to access the internet.
@@ -32,7 +33,6 @@ TEST_WITH_INTERNET = False
 
 # Skip Secure WebSocket test.
 TEST_SECURE_WS = False
-
 TRACABLE = False
 
 
@@ -524,6 +524,12 @@ class SockOptTest(unittest.TestCase):
         self.assertNotEqual(s.sock.getsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY), 0)
         s.close()
 
+class UtilsTest(unittest.TestCase):
+    def testUtf8Validator(self):
+        state = validate_utf8(six.b('\xf0\x90\x80\x80'))
+        self.assertEqual(state, True) 
+        state = validate_utf8(six.b('\xce\xba\xe1\xbd\xb9\xcf\x83\xce\xbc\xce\xb5\xed\xa0\x80edited'))
+        self.assertEqual(state, False)
 
 if __name__ == "__main__":
     unittest.main()