将 Javascript 加密算法转换为 Python

小能豆

将 Javascript 加密算法转换为 Python

python

我有一个 JavaScript 加密算法，我正在尝试将其转换为 Python。我尝试研究算法，虽然它不是太复杂，但我无法完全理解并将其转换为 Python 代码。JavaScript代码是

var grecaptcha = [];
enc = function (a) {
var keyBytes = CryptoJS.PBKDF2('lrvq/wyDf6tqhxvg8NuIDQ==', 'Ivan Medvedev', { keySize: 48 / 4, iterations: 1000 });
// take first 32 bytes as key (like in C# code)
var key = new CryptoJS.lib.WordArray.init(keyBytes.words, 32);
// skip first 32 bytes and take next 16 bytes as IV
var iv = new CryptoJS.lib.WordArray.init(keyBytes.words.splice(32 / 4), 16);
// use the same encoding as in C# code, to convert string into bytes
var data = CryptoJS.enc.Utf16LE.parse(a);
var encrypted = CryptoJS.AES.encrypt(data, key, { iv: iv });
$("#capBBC").val(encrypted.toString());
}

我能够编写的 Python 代码是

from Crypto.Protocol.KDF import PBKDF2
from Crypto.Cipher import AES
from Crypto.Util.Padding import pad

def enc(a):
    key = PBKDF2("lrvq/wyDf6tqhxvg8NuIDQ==", "Ivan Medvedev", dkLen=48, count=1000)
    iv = key[32:]
    data = a.encode('utf-16le')

    cipher = AES.new(key, AES.MODE_CBC, iv)
    encrypted = cipher.encrypt(pad(data, AES.block_size))

    return encrypted.hex()

print(enc("Cat"))

此代码引发以下异常

Traceback (most recent call last):
  File "C:\Users\Farhan Ahmed\Desktop\code\Python\Kiara Snickers\del.py", line 16, in <module>
    print(enc("Cat"))
  File "C:\Users\Farhan Ahmed\Desktop\code\Python\Kiara Snickers\del.py", line 11, in enc
    cipher = AES.new(key, AES.MODE_CBC, iv)
  File "C:\Users\Farhan Ahmed\AppData\Local\Programs\Python\Python310\lib\site-packages\Crypto\Cipher\AES.py", line 232, in new
    return _create_cipher(sys.modules[__name__], key, mode, *args, **kwargs)
  File "C:\Users\Farhan Ahmed\AppData\Local\Programs\Python\Python310\lib\site-packages\Crypto\Cipher\__init__.py", line 79, in _create_cipher
    return modes[mode](factory, **kwargs)
  File "C:\Users\Farhan Ahmed\AppData\Local\Programs\Python\Python310\lib\site-packages\Crypto\Cipher\_mode_cbc.py", line 274, in _create_cbc_cipher
    cipher_state = factory._create_base_cipher(kwargs)
  File "C:\Users\Farhan Ahmed\AppData\Local\Programs\Python\Python310\lib\site-packages\Crypto\Cipher\AES.py", line 93, in _create_base_cipher
    raise ValueError("Incorrect AES key length (%d bytes)" % len(key))
ValueError: Incorrect AES key length (48 bytes)

我不知道 dkLen 的价值应该是多少提前感谢您的帮助。

阅读 146

2023-06-16

共1个答案

小能豆

在 CryptoJS 代码中，PBKDF2 返回的数据的前 32 个字节用作密钥，但在 Python 代码中是整个数据。
这是 48 字节大，与有效的 AES 密钥不对应，因此导致错误Incorrect AES key length (48 bytes)。
此外，CryptoJS 代码中的密文返回的是 Base64 编码，而不是十六进制编码。

两者的可能解决方法是：

from Crypto.Protocol.KDF import PBKDF2
from Crypto.Cipher import AES
from Crypto.Util.Padding import pad
import base64

def enc(a):
    keyIv = PBKDF2("lrvq/wyDf6tqhxvg8NuIDQ==", "Ivan Medvedev", dkLen=48, count=1000)
    key = keyIv[:32]
    iv = keyIv[32:]
    data = a.encode('utf-16le')

    cipher = AES.new(key, AES.MODE_CBC, iv)
    encrypted = cipher.encrypt(pad(data, AES.block_size))

    return base64.b64encode(encrypted).decode('utf-8')

print(enc("Cat")) # CZ/1nUYEjhw4cFj08Yt1EQ==

它返回对应于 CryptoJS 代码的密文：

enc = function (a) {
    var keyBytes = CryptoJS.PBKDF2('lrvq/wyDf6tqhxvg8NuIDQ==', 'Ivan Medvedev', { keySize: 48 / 4, iterations: 1000 });
    // take first 32 bytes as key (like in C# code)
    var key = new CryptoJS.lib.WordArray.init(keyBytes.words, 32);
    // skip first 32 bytes and take next 16 bytes as IV
    var iv = new CryptoJS.lib.WordArray.init(keyBytes.words.splice(32 / 4), 16);
    // use the same encoding as in C# code, to convert string into bytes
    var data = CryptoJS.enc.Utf16LE.parse(a);
    var encrypted = CryptoJS.AES.encrypt(data, key, { iv: iv });
    console.log(encrypted.toString());
}
enc("Cat")
<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/4.1.1/crypto-js.min.js"></script>

2023-06-16