Python基于pycrypto实现的AES加密和解密算法示例

# -*- coding: UTF-8 -*-
import string
import random
from Crypto.Cipher import AES
def keyGenerater(length):
  '''''生成指定长度的秘钥'''
  if length not in (16,24,32):
    return None
  x = string.ascii_letters+string.digits
  return ''.join([random.choice(x) for i in range(length)])
def encryptor_decryptor(key,mode):
  return AES.new(key,mode,b'0000000000000000')
#使用指定密钥和模式对给定信息进行加密
def AESencrypt(key,text):
  encryptor = encryptor_decryptor(key,mode)
  return encryptor.encrypt(text)
#使用指定密钥和模式对给定信息进行解密
def AESdecrypt(key,text):
  decryptor = encryptor_decryptor(key,mode)
  return decryptor.decrypt(text)
if __name__ == '__main__':
  text = 'Python3.5 is excellent.'
  key = keyGenerater(16)
  #随机选择AES的模式
  mode = random.choice((AES.MODE_CBC,AES.MODE_CFB,AES.MODE_ECB,AES.MODE_OFB))
  if not key:
    print('Something is wrong.')
  else:
    print('key:',key)
    print('mode:',mode)
    print('Before encryption:',text)
    #明文必须以字节串形式，且长度为16的倍数
    text_encoded = text.encode()
    text_length = len(text_encoded)
    padding_length = 16 - text_length%16
    text_encoded = text_encoded + b'0'*padding_length
    text_encrypted = AESencrypt(key,text_encoded)
    print('After encryption:',text_encrypted)
    text_decrypted =AESdecrypt(key,text_encrypted)
    print('After decryption:',text_decrypted.decode()[:-padding_length])