AES ECB Encrypting in Python

问题

My main goal is to rewrite this javascript into python

password = "AAAABBBBCCCC";
passwordMd5 = CryptoJS.MD5(password); 
    //e1b6b2b3211076a71632bbf2ad0edc05
passwordKey = CryptoJS.SHA256(CryptoJS.SHA256(passwordMd5 + data.v1) + data.v2); 
    //4a5148da63f40e1bcd3e3225f9b79412b7aee745f4b7f831b9d0893d0d6d666f
encryptedPassword = CryptoJS.AES.encrypt(passwordMd5, passwordKey, {mode: CryptoJS.mode.ECB,padding: CryptoJS.pad.NoPadding});
    //U2FsdGVkX198V2FiYyEGAKISlXBcmad7V0scbooxQ8QMSmp84vtyAfHytynX2mrw
encryptedPassword = CryptoJS.enc.Base64.parse(encryptedPassword.toString()).toString(CryptoJS.enc.Hex);
//53616c7465645f5f7c57616263210600a21295705c99a77b574b1c6e8a3143c40c4a6a7ce2fb7201f1f2b729d7da6af0

Here is my code in python

passwordMd5 = hashlib.md5(password.encode("utf-8")).hexdigest()
# e1b6b2b3211076a71632bbf2ad0edc05
passwordKey = hashlib.sha256((hashlib.sha256((passwordMd5 + prelogin["v1"]).encode("utf-8")).hexdigest() + prelogin["v2"]).encode("utf-8")).hexdigest()
# 4a5148da63f40e1bcd3e3225f9b79412b7aee745f4b7f831b9d0893d0d6d666f
cipher = AESCipher(passwordKey)
encryptedPassword = cipher.encrypt(passwordMd5)
print(encryptedPassword)

AESCipher.py (original: here),

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

BS = 32
def pad(s): s + (BS - len(s) % BS) * chr(BS - len(s) % BS).encode()
def unpad(s): s[:-ord(s[len(s)-1:])]

class AESCipher(object):

    def __init__(self, key):
        self.key = key

    def encrypt(self, message):
        message = message.encode()
        raw = pad(message)
        cipher = AES.new(self.key, AES.MODE_ECB)
        enc = cipher.encrypt(raw)
        return base64.b64encode(enc).decode('utf-8')

    def decrypt(self, enc):
        enc = base64.b64decode(enc)
        cipher = AES.new(self.key, AES.MODE_ECB)
        dec = cipher.decrypt(enc)
        return unpad(dec).decode('utf-8')

When i try to run it, it give me error:

 Traceback (most recent call last):
  File "main.py", line 97, in <module>
    encryptedPassword = cipher.encrypt(passwordMd5)
  File "AESCipher.py", line 31, in encrypt
    cipher = AES.new(self.key, AES.MODE_ECB)
  File "python\lib\site-packages\Crypto\Cipher\AES.py", line 206, in new
    return _create_cipher(sys.modules[__name__], key, mode, *args, **kwargs)
File "python\lib\site-packages\Crypto\Cipher\__init__.py", line 79, in _create_cipher
    return modes[mode](factory, **kwargs)
  File "python\lib\site-packages\Crypto\Cipher\_mode_ecb.py", line 177, in _create_ecb_cipher
    cipher_state = factory._create_base_cipher(kwargs)
  File "python\lib\site-packages\Crypto\Cipher\AES.py", line 92, in _create_base_cipher
    raise ValueError("Incorrect AES key length (%d bytes)" % len(key))
ValueError: Incorrect AES key length (64 bytes)

i know the key is 64 bytes length but the javascript version worked perfectly with the same passwordKey.

I dont know what is wrong with my code, plz help!

回答1:

Actually AES key should be either 16, 24 or 32 bytes long.

You are using the hexdigest of a sha256 hash as a key, which results in a 64 bytes string. Instead do the following:

password = (hashlib.sha256((passwordMd5 + prelogin["v1"])).hexdigest() + prelogin["v2"])
passwordKey = hashlib.sha256(password).digest()

来源：https://stackoverflow.com/questions/51884553/aes-ecb-encrypting-in-python

标签

python

aes

python-3.7