encrypt_decrypt_demo.py

# coding: utf-8

import md5
from Crypto import Random
from Crypto.Cipher import AES
import base64


BLOCK_SIZE = 16


def trans(key):
    return md5.new(key).digest()


def encrypt(message, passphrase):
    passphrase = trans(passphrase)
    IV = Random.new().read(BLOCK_SIZE)
    aes = AES.new(passphrase, AES.MODE_CFB, IV)
    return base64.b64encode(IV + aes.encrypt(message))


def decrypt(encrypted, passphrase):
    passphrase = trans(passphrase)
    encrypted = base64.b64decode(encrypted)
    IV = encrypted[:BLOCK_SIZE]
    aes = AES.new(passphrase, AES.MODE_CFB, IV)
    return aes.decrypt(encrypted[BLOCK_SIZE:])


def main():
    passphrase = '123'
    message = 'TheXX'
    encrypted = encrypt(message, passphrase)
    decrypted = decrypt(encrypted, passphrase)
    assert decrypted == message

    print("passphrase: %s" % passphrase)
    print("message: %s" % message)
    print("encrypted: %s" % encrypted)
    print("decrypted: %s" % decrypted)


if __name__ == '__main__':
    main()