Implement AES-GCM in tlslite.

third_party/tlslite/tlslite/utils/aes.py

 # Author: Trevor Perrin
 # See the LICENSE file for legal information regarding use of this file.
 
 """Abstract class for AES."""
 
 class AES(object):
     def __init__(self, key, mode, IV, implementation):
         if len(key) not in (16, 24, 32):
             raise AssertionError()
         if mode != 2:
             raise AssertionError()
         if len(IV) != 16:
             raise AssertionError()
         self.isBlockCipher = True
+        self.isAEAD = False
         self.block_size = 16
         self.implementation = implementation
         if len(key)==16:
             self.name = "aes128"
         elif len(key)==24:
             self.name = "aes192"
         elif len(key)==32:
             self.name = "aes256"
         else:
             raise AssertionError()
 
     #CBC-Mode encryption, returns ciphertext
     #WARNING: *MAY* modify the input as well
     def encrypt(self, plaintext):
         assert(len(plaintext) % 16 == 0)
 
     #CBC-Mode decryption, returns plaintext
     #WARNING: *MAY* modify the input as well
     def decrypt(self, ciphertext):
-        assert(len(ciphertext) % 16 == 0)
+        assert(len(ciphertext) % 16 == 0)