对称加密 AES

aes.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# 参考资料:
# * https://en.wikipedia.org/wiki/Advanced_Encryption_Standard
# * https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation
# 
# Show AES document:
# > from Crypto.Cipher import AES
# > help(AES)

from Crypto import Random
from Crypto.Cipher import AES
from binascii import b2a_hex, a2b_hex

KEY_SIZE = 16


def generate_key(key_size=KEY_SIZE):
    """ 生成随机密钥，默认长度为 128 bits
    """
    return Random.new().read(key_size)


def encrypt(key, plaintext):
    iv = Random.new().read(AES.block_size)
    cipher = AES.new(key, AES.MODE_CFB, iv)
    return iv + cipher.encrypt(plaintext)


def decrypt(key, ciphertext):
    iv = ciphertext[:16]
    cipher = AES.new(key, AES.MODE_CFB, iv)
    return cipher.decrypt(ciphertext[16:])


if __name__ == '__main__':
    key = generate_key()
    plaintext = u'abc'
    ciphertext = encrypt(key, plaintext)
    plaintext = decrypt(key, ciphertext)
    print plaintext
    print ciphertext
    # 计算出来的 ciphertext 是二进制，输出可转化成十六进制
    print b2a_hex(ciphertext)