Python中使用AES算法（解决Python2.x和3.x下运行不兼容问题）

两年前使用python时，碰到2.x下AES加密解密算法代码无法在3.x下顺利运行，花点时间解决了兼容问题，在2.7、3.6、3.7下运行良好。

Linux系统安装依赖库比较简单，Windows下稍嫌繁琐，装完必须的库也可以正常运行。

代码整理如下：

# -*- coding: utf-8 -*-

import base64
import sys
 
from Crypto import Random
from Crypto.Cipher import AES
 
 
# Author: areful
# Date: 2017-07-06
class AESCipher:
 
    def __init__(self, key, iv=Random.new().read(AES.block_size)):
        self.key = key
        self.iv = iv
        self.mode = AES.MODE_CBC
 
        if sys.version > '3':
            self.PY3 = True
        else:
            self.PY3 = False
 
    def encrypt(self, text):
        if self.PY3:
            return self.encrypt36(text)
        else:
            return self.encrypt27(text)
 
    def encrypt27(self, text):
        cipher = AES.new(self.key, AES.MODE_CBC, self.iv)
 
        bs = AES.block_size
        text_length = len(text)
        amount_to_pad = bs - (text_length % bs)
        if amount_to_pad == 0:
            amount_to_pad = bs
        pad = chr(amount_to_pad)
        text1 = text + pad * amount_to_pad
        cipher_text = cipher.encrypt(text1)
        return base64.b64encode(cipher_text)
 
    def encrypt36(self, text):
        cipher = AES.new(self.key, AES.MODE_CBC, self.iv)
 
        bs = AES.block_size
        text_length = len(text.encode('utf-8'))
        amount_to_pad = bs - (text_length % bs)
        if amount_to_pad == 0:
            amount_to_pad = bs
        pad = chr(amount_to_pad)
        text1 = text + pad * amount_to_pad
        cipher_text = cipher.encrypt(text1)
        encrypted_str = str(base64.b64encode(cipher_text), encoding='utf-8')
        return encrypted_str
 
    def decrypt(self, text):
        import base64
        base_text = base64.b64decode(text)
        cipher = AES.new(self.key, self.mode, self.iv)
        plain_text = cipher.decrypt(base_text).decode('utf-8')
        pad = ord(plain_text[-1])
        ne = plain_text[:-pad]
        return ne
 
    @staticmethod
    def pad(s):
        bs = AES.block_size
        return s + (bs - len(s) % bs) * chr(bs - len(s) % bs)
 
    @staticmethod
    def unpad(s):
        return s[0:-ord(s[-1])]
 
    @staticmethod
    def __pad(text):
        text_length = len(text)
        amount_to_pad = AES.block_size - (text_length % AES.block_size)
        if amount_to_pad == 0:
            amount_to_pad = AES.block_size
        pad = chr(amount_to_pad)
        return text + pad * amount_to_pad
 
    @staticmethod
    def __unpad(text):
        pad = ord(text[-1])
        return text[:-pad]
 
    @staticmethod
    def test(key, iv, text):
        cipher = AESCipher(key, iv)
        encrypted_msg = cipher.encrypt(text)
        print(encrypted_msg)
        msg = cipher.decrypt(encrypted_msg)
        print(msg)
 
 
if __name__ == '__main__':
    AESCipher.test('ABCDEFGHICKLMNOP',
                   bytes(bytearray(b'\x01\x02\x03\x04\x05\x06\x07\x08\x41\x42\x43\x44\x45\x46\x47\x48')),
                   'areful.测试文本')