added gcm

pyaes/__init__.py

@@ -48,6 +48,6 @@
 
 VERSION = [1, 3, 0]
 
-from .aes import AES, AESModeOfOperationCTR, AESModeOfOperationCBC, AESModeOfOperationCFB, AESModeOfOperationECB, AESModeOfOperationOFB, AESModesOfOperation, Counter
+from .aes import AES, AESModeOfOperationCTR, AESModeOfOperationCBC, AESModeOfOperationCFB, AESModeOfOperationECB, AESModeOfOperationOFB, AESModeOfOperationGCM, AESModesOfOperation, Counter
 from .blockfeeder import decrypt_stream, Decrypter, encrypt_stream, Encrypter
 from .blockfeeder import PADDING_NONE, PADDING_DEFAULT

pyaes/aes.py

@@ -55,7 +55,7 @@
 import struct
 
 __all__ = ["AES", "AESModeOfOperationCTR", "AESModeOfOperationCBC", "AESModeOfOperationCFB",
-           "AESModeOfOperationECB", "AESModeOfOperationOFB", "AESModesOfOperation", "Counter"]
+           "AESModeOfOperationECB", "AESModeOfOperationOFB", "AESModeOfOperationGCM", "AESModesOfOperation", "Counter"]
 
 
 def _compact_word(word):
@@ -578,6 +578,15 @@ def decrypt(self, crypttext):
         # AES-CTR is symetric
         return self.encrypt(crypttext)
 
+class AESModeOfOperationGCM(AESModeOfOperationCTR):
+    name = "GCM"
+
+    def __init__(self, key, iv):
+        iv = iv + b"\x00\x00\x00\x02"
+        iv_int = 0
+        for i in xrange(0, len(iv), 4):
+            iv_int = (iv_int << 32) + struct.unpack('>I', iv[i:i+4])[0]
+        AESModeOfOperationCTR.__init__(self, key, counter=Counter(iv_int))
 
 # Simple lookup table for each mode
 AESModesOfOperation = dict(
@@ -586,4 +595,5 @@ def decrypt(self, crypttext):
     cfb = AESModeOfOperationCFB,
     ecb = AESModeOfOperationECB,
     ofb = AESModeOfOperationOFB,
+    gcm = AESModeOfOperationGCM,
 )

setup.py

@@ -1,14 +1,16 @@
 #!/usr/bin/env python
-
-from distutils.core import setup
+try:
+  from setuptools import setup
+except ImportError:
+  from distutils.core import setup
 
 LONG_DESCRIPTION = '''A pure-Python implementation of the AES (FIPS-197)
 block-cipher algorithm and common modes of operation (CBC, CFB, CTR, ECB,
 OFB) with no dependencies beyond standard Python libraries. See README.md
 for API reference and details.'''
 
 setup(name = 'pyaes',
-      version = '1.6.1',
+      version = '1.6.2',
       description = 'Pure-Python Implementation of the AES block-cipher and common modes of operation',
       long_description = LONG_DESCRIPTION,
       author = 'Richard Moore',

tests/test-aes.py

@@ -39,7 +39,7 @@
 # compare against a known working implementation
 from Crypto.Cipher import AES as KAES
 from Crypto.Util import Counter as KCounter
-for mode in [ 'CBC', 'CTR',  'CFB', 'ECB', 'OFB' ]:
+for mode in [ 'CBC', 'CTR', 'GCM', 'CFB', 'ECB', 'OFB' ]:
 
     (tt_ksetup, tt_kencrypt, tt_kdecrypt) = (0.0, 0.0, 0.0)
     (tt_setup, tt_encrypt, tt_decrypt) = (0.0, 0.0, 0.0)
@@ -122,6 +122,23 @@
                 aes2 = AESModeOfOperationCTR(key, counter = Counter(initial_value = 0))
                 tt_setup += time.time() - t0
 
+            elif mode == 'GCM':
+                text_length = [None, 3, 16, 127, 128, 129, 1500, 10000, 100000, 10001, 10002, 10003, 10004, 10005, 10006, 10007, 10008][test]
+                if test < 6:
+                    plaintext = [ os.urandom(text_length) ]
+                else:
+                    plaintext = [ os.urandom(text_length) for x in xrange(0, test) ]
+                iv = os.urandom(12)
+
+                t0 = time.time()
+                kaes = KAES.new(key, KAES.MODE_GCM, iv)
+                kaes2 = KAES.new(key, KAES.MODE_GCM, iv)
+                tt_ksetup += time.time() - t0
+
+                t0 = time.time()
+                aes = AESModeOfOperationGCM(key, iv)
+                aes2 = AESModeOfOperationGCM(key, iv)
+                tt_setup += time.time() - t0
             count += 1
 
             t0 = time.time()