diff --git a/IPSC Decoding.txt b/IPSC Decoding.txt
index 76d7d89..8cab7ab 100644
--- a/IPSC Decoding.txt	
+++ b/IPSC Decoding.txt	
@@ -9,6 +9,7 @@ PEER:
        13120104
 	   
 MASTER:
+91   00 04 c2 c0   6a   00 00 80 5d 00 06   04 03      04 00     9b 1d 56 20 26 48 08 e3 60 ba
 91   00 04 c2 c0   6a   00 00 80 5d 00 03   04 03      04 00     5c b8 4e e4 7e 44 b6 bb df dd
      |--SRC ID-| |MODE| |  FLAGS  ||PEERS||IPSC VER| |IPSC VER|  |-1st 10 bytes of SHA-1 Hash-|
 	     312000
diff --git a/ipsc.py b/ipsc.py
index 83355d2..133c703 100644
--- a/ipsc.py
+++ b/ipsc.py
@@ -61,7 +61,17 @@ def hashed_packet(_key, _data):
 # Take a RECEIVED packet, calculate the auth hash and verify authenticity
 #
 def validate_auth(_key, _data):
-    return
+    _log = logger.info
+    _payload = _data[:-10]
+    _hash = _data[-10:]
+    _chk_hash = binascii.unhexlify((hmac.new(_key,_payload,hashlib.sha1)).hexdigest()[:20])
+    
+    if _chk_hash == _hash:
+        _log('    AUTH: Valid   - Payload: %s, Hash: %s', binascii.hexlify(_payload), binascii.hexlify(_hash))
+        return True
+    else:
+        _log('    AUTH: Invalid - Payload: %s, Hash: %s', binascii.hexlify(_payload), binascii.hexlify(_hash))
+        return False
 
 def process_peer_list(_data, _network):
     _log = logger.info
@@ -305,6 +315,10 @@ class IPSC(DatagramProtocol):
         _packettype = data[0:1]
         _peerid     = data[1:5]
         _dec_peerid = int(binascii.b2a_hex(_peerid), 16)
+        
+        if validate_auth(self._local['AUTH_KEY'], data) == False:
+            logger.error('AuthError: IPSC packet failed authentication. Type %s: Peer ID: %s', _packettype, _dec_peerid)
+            return
 
         if (_packettype == PEER_ALIVE_REQ):
             logger.debug('<<- (%s) Peer Keep-alive Request From Peer ID %s at:%s:%s', self._network, _dec_peerid, host, port)
diff --git a/my_ipsc_config_SAMPLE.py b/my_ipsc_config_SAMPLE.py
index 7501ef0..8e88c9d 100644
--- a/my_ipsc_config_SAMPLE.py
+++ b/my_ipsc_config_SAMPLE.py
@@ -43,6 +43,10 @@ NETWORK = {
 #           'PORT': 50000,
 #           'RADIO_ID': b'\x00\x00\x00\x00',
 #           'MODE': b'\x00,
+#           'PEER_OPER': False,
+#           'PEER_MODE': '',
+#           'TS1_LINK': False,
+#           'TS2_LINK': False,
 #           'FLAGS': b'\x00\x00\x00\x00',
 #           'STATUS': {
 #               'CONNECTED': False,