diff --git a/third_party/tlslite/tlslite/constants.py b/third_party/tlslite/tlslite/constants.py
index 6429c66..8720de6 100644
--- a/third_party/tlslite/tlslite/constants.py
+++ b/third_party/tlslite/tlslite/constants.py
@@ -45,6 +45,7 @@ class ExtensionType:    # RFC 6066 / 4366
     server_name = 0     # RFC 6066 / 4366
     srp = 12            # RFC 5054  
     cert_type = 9       # RFC 6091
+    signed_cert_timestamps = 18  # RFC 6962
     tack = 0xF300
     supports_npn = 13172
     channel_id = 30032
diff --git a/third_party/tlslite/tlslite/messages.py b/third_party/tlslite/tlslite/messages.py
index 4fa9d96..876b033 100644
--- a/third_party/tlslite/tlslite/messages.py
+++ b/third_party/tlslite/tlslite/messages.py
@@ -114,6 +114,7 @@ class ClientHello(HandshakeMsg):
         self.supports_npn = False
         self.server_name = bytearray(0)
         self.channel_id = False
+        self.support_signed_cert_timestamps = False
 
     def create(self, version, random, session_id, cipher_suites,
                certificate_types=None, srpUsername=None,
@@ -183,6 +184,10 @@ class ClientHello(HandshakeMsg):
                                 break
                     elif extType == ExtensionType.channel_id:
                         self.channel_id = True
+                    elif extType == ExtensionType.signed_cert_timestamps:
+                        if extLength:
+                            raise SyntaxError()
+                        self.support_signed_cert_timestamps = True
                     else:
                         _ = p.getFixBytes(extLength)
                     index2 = p.index
@@ -248,6 +253,7 @@ class ServerHello(HandshakeMsg):
         self.next_protos_advertised = None
         self.next_protos = None
         self.channel_id = False
+        self.signed_cert_timestamps = None
 
     def create(self, version, random, session_id, cipher_suite,
                certificate_type, tackExt, next_protos_advertised):
@@ -337,6 +343,9 @@ class ServerHello(HandshakeMsg):
         if self.channel_id:
             w2.add(ExtensionType.channel_id, 2)
             w2.add(0, 2)
+        if self.signed_cert_timestamps:
+            w2.add(ExtensionType.signed_cert_timestamps, 2)
+            w2.addVarSeq(bytearray(self.signed_cert_timestamps), 1, 2)
         if len(w2.bytes):
             w.add(len(w2.bytes), 2)
             w.bytes += w2.bytes        
diff --git a/third_party/tlslite/tlslite/tlsconnection.py b/third_party/tlslite/tlslite/tlsconnection.py
index b0400f8..4dedc5f 100644
--- a/third_party/tlslite/tlslite/tlsconnection.py
+++ b/third_party/tlslite/tlslite/tlsconnection.py
@@ -969,7 +969,7 @@ class TLSConnection(TLSRecordLayer):
                         reqCAs = None, 
                         tacks=None, activationFlags=0,
                         nextProtos=None, anon=False,
-                        tlsIntolerant=None):
+                        tlsIntolerant=None, signedCertTimestamps=None):
         """Perform a handshake in the role of server.
 
         This function performs an SSL or TLS handshake.  Depending on
@@ -1043,6 +1043,11 @@ class TLSConnection(TLSRecordLayer):
         simulate TLS version intolerance by returning a fatal handshake_failure
         alert to all TLS versions tlsIntolerant or higher.
 
+        @type signedCertTimestamps: str
+        @param signedCertTimestamps: A SignedCertificateTimestampList (as a
+        binary 8-bit string) that will be sent as a TLS extension whenever
+        the client announces support for the extension.
+
         @raise socket.error: If a socket error occurs.
         @raise tlslite.errors.TLSAbruptCloseError: If the socket is closed
         without a preceding alert.
@@ -1054,7 +1059,8 @@ class TLSConnection(TLSRecordLayer):
                 certChain, privateKey, reqCert, sessionCache, settings,
                 checker, reqCAs, 
                 tacks=tacks, activationFlags=activationFlags, 
-                nextProtos=nextProtos, anon=anon, tlsIntolerant=tlsIntolerant):
+                nextProtos=nextProtos, anon=anon, tlsIntolerant=tlsIntolerant,
+                signedCertTimestamps=signedCertTimestamps):
             pass
 
 
@@ -1064,7 +1070,8 @@ class TLSConnection(TLSRecordLayer):
                              reqCAs=None, 
                              tacks=None, activationFlags=0,
                              nextProtos=None, anon=False,
-                             tlsIntolerant=None
+                             tlsIntolerant=None,
+                             signedCertTimestamps=None
                              ):
         """Start a server handshake operation on the TLS connection.
 
@@ -1084,7 +1091,8 @@ class TLSConnection(TLSRecordLayer):
             reqCAs=reqCAs, 
             tacks=tacks, activationFlags=activationFlags, 
             nextProtos=nextProtos, anon=anon,
-            tlsIntolerant=tlsIntolerant)
+            tlsIntolerant=tlsIntolerant,
+            signedCertTimestamps=signedCertTimestamps)
         for result in self._handshakeWrapperAsync(handshaker, checker):
             yield result
 
@@ -1094,7 +1102,7 @@ class TLSConnection(TLSRecordLayer):
                              settings, reqCAs, 
                              tacks, activationFlags, 
                              nextProtos, anon,
-                             tlsIntolerant):
+                             tlsIntolerant, signedCertTimestamps):
 
         self._handshakeStart(client=False)
 
@@ -1115,6 +1123,9 @@ class TLSConnection(TLSRecordLayer):
                 raise ValueError("tackpy is not loaded")
             if not settings or not settings.useExperimentalTackExtension:
                 raise ValueError("useExperimentalTackExtension not enabled")
+        if signedCertTimestamps and not certChain:
+            raise ValueError("Caller passed signedCertTimestamps but no "
+                             "certChain")
 
         if not settings:
             settings = HandshakeSettings()
@@ -1159,6 +1170,8 @@ class TLSConnection(TLSRecordLayer):
                             cipherSuite, CertificateType.x509, tackExt,
                             nextProtos)
         serverHello.channel_id = clientHello.channel_id
+        if clientHello.support_signed_cert_timestamps:
+            serverHello.signed_cert_timestamps = signedCertTimestamps
 
         # Perform the SRP key exchange
         clientCertChain = None