AES MODE_GCM_aes.mode_gcm

python  需要安装： PyCryptodome

示例代码：
 

from Crypto.Cipher import AES
 
 
key="1111111111111111"
iv="000000000000"
msg="2222222222222222"
 
#加密
cipher = AES.new(key, AES.MODE_GCM, iv)
en_msg=cipher.encrypt(msg)
#print en_msg,
print "en_msg(hex)",en_msg.encode('hex')
 
#解密
cipher1 = AES.new(key, AES.MODE_GCM, iv)
de_msg=cipher1.decrypt(en_msg)
print "msg:",de_msg

这个解密也不需要tag值。

python27\Lib\site-packages\Crypto\Cipher\_mode_gcm.py

# ===================================================================
#
# Copyright (c) 2014, Legrandin <helderijs@gmail.com>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in
#    the documentation and/or other materials provided with the
#    distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
# COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
# ===================================================================
 
"""
Galois/Counter Mode (GCM).
"""
 
__all__ = ['GcmMode']
 
from binascii import unhexlify
 
from Crypto.Util.py3compat import bord, _copy_bytes
 
from Crypto.Util._raw_api import is_buffer
 
from Crypto.Util.number import long_to_bytes, bytes_to_long
from Crypto.Hash import BLAKE2s
from Crypto.Random import get_random_bytes
 
from Crypto.Util._raw_api import (load_pycryptodome_raw_lib, VoidPointer,
                                  create_string_buffer, get_raw_buffer,
                                  SmartPointer, c_size_t, c_uint8_ptr)
 
from Crypto.Util import _cpu_features
 
 
# C API by module implementing GHASH
_ghash_api_template = """
    int ghash_%imp%(uint8_t y_out[16],
                    const uint8_t block_data[],
                    size_t len,
                    const uint8_t y_in[16],
                    const void *exp_key);
    int ghash_expand_%imp%(const uint8_t h[16],
                           void **ghash_tables);
    int ghash_destroy_%imp%(void *ghash_tables);
"""
 
def _build_impl(lib, postfix):
    from collections import namedtuple
 
    funcs = ( "ghash", "ghash_expand", "ghash_destroy" )
    GHASH_Imp = namedtuple('_GHash_Imp', funcs)
    try:
        imp_funcs = [ getattr(lib, x + "_" + postfix) for x in funcs ]
    except AttributeError:      # Make sphinx stop complaining with its mocklib
        imp_funcs = [ None ] * 3
    params = dict(zip(funcs, imp_funcs))
    return GHASH_Imp(**params)
 
 
def _get_ghash_portable():
    api = _ghash_api_template.replace("%imp%", "portable")
    lib = load_pycryptodome_raw_lib("Crypto.Hash._ghash_portable", api)
    result = _build_impl(lib, "portable")
    return result
_ghash_portable = _get_ghash_portable()
 
 
def _get_ghash_clmul():
    """Return None if CLMUL implementation is not available"""
 
    if not _cpu_features.have_clmul():
        return None
    try:
        api = _ghash_api_template.replace("%imp%", "clmul")
        lib = load_pycryptodome_r