Implement AES-GCM in tlslite.

third_party/tlslite/tlslite/utils/cipherfactory.py

 # Author: Trevor Perrin
 # See the LICENSE file for legal information regarding use of this file.
 
 """Factory functions for symmetric cryptography."""
 
 import os
 
 from tlslite.utils import python_aes
+from tlslite.utils import python_aesgcm
 from tlslite.utils import python_rc4
 
 from tlslite.utils import cryptomath
 
 tripleDESPresent = False
 
 if cryptomath.m2cryptoLoaded:
     from tlslite.utils import openssl_aes
     from tlslite.utils import openssl_rc4
     from tlslite.utils import openssl_tripledes
     tripleDESPresent = True
 
 if cryptomath.pycryptoLoaded:
     from tlslite.utils import pycrypto_aes
+    from tlslite.utils import pycrypto_aesgcm
     from tlslite.utils import pycrypto_rc4
     from tlslite.utils import pycrypto_tripledes
     tripleDESPresent = True
 
 # **************************************************************************
 # Factory Functions for AES
 # **************************************************************************
 
 def createAES(key, IV, implList=None):
     """Create a new AES object.
@@ skipping 12 matching lines @@
 
     for impl in implList:
         if impl == "openssl" and cryptomath.m2cryptoLoaded:
             return openssl_aes.new(key, 2, IV)
         elif impl == "pycrypto" and cryptomath.pycryptoLoaded:
             return pycrypto_aes.new(key, 2, IV)
         elif impl == "python":
             return python_aes.new(key, 2, IV)
     raise NotImplementedError()
 
+def createAESGCM(key, implList=None):
+    """Create a new AESGCM object.
+
+    @type key: bytearray
+    @param key: A 16 or 32 byte byte array.
+
+    @rtype: L{tlslite.utils.AESGCM}
+    @return: An AESGCM object.
+    """
+    if implList == None:
+        implList = ["pycrypto", "python"]

[davidben, 2015/01/25 02:43:41]

"openssl", or rather, M2Crypto is intentionally omitted here. It doesn't expose
OpenSSL's actual AES-GCM implementation. I did try to use AES_encrypt to
implement the raw block cipher, but M2Crypto's low-level AES wrappers... don't
actually work...

https://github.com/M2Crypto/M2Crypto/blob/master/SWIG/_aes.i (note what gets
passed into AES_encrypt's first argument)

...and then I decided this wasn't worth bothering with, though we could
certainly pull the raw block cipher out of an ECB mode or something.

+
+    for impl in implList:
+        if impl == "pycrypto" and cryptomath.pycryptoLoaded:
+            return pycrypto_aesgcm.new(key)
+        if impl == "python":
+            return python_aesgcm.new(key)
+    raise NotImplementedError()
+
 def createRC4(key, IV, implList=None):
     """Create a new RC4 object.
 
     @type key: str
     @param key: A 16 to 32 byte string.
 
     @type IV: object
     @param IV: Ignored, whatever it is.
 
     @rtype: L{tlslite.utils.RC4}
@@ skipping 27 matching lines @@
     @return: A 3DES object.
     """
     if implList == None:
         implList = ["openssl", "pycrypto"]
 
     for impl in implList:
         if impl == "openssl" and cryptomath.m2cryptoLoaded:
             return openssl_tripledes.new(key, 2, IV)
         elif impl == "pycrypto" and cryptomath.pycryptoLoaded:
             return pycrypto_tripledes.new(key, 2, IV)
-    raise NotImplementedError()
+    raise NotImplementedError()