使用 HKDF 密钥的 Crypto-js 加密和 Python 解密

Question

根据关于如何在 JS (Crypto-JS) 和 Python 之间建立共享密钥和派生密钥的，我最终可以得到相同的共享密钥和派生密钥两端。

然而，当我尝试如下加密时，我找不到从 Python 正确解密的方法。我的理解是，我可能弄乱了填充或盐和哈希值。

    const payload = "hello"
    var iv = CryptoJS.enc.Utf8.parse("1020304050607080");

    var test = CryptoJS.AES.encrypt(
        payload,
        derived_key,
        {iv: iv, mode: CryptoJS.mode.CBC}
    ).toString();

    console.log(test)

输出“y+In4kriw0qy4lji6/x14g==”

Python（其中一次尝试）：

from Crypto.Cipher import AES
from Crypto.Util.Padding import pad,unpad

iv = "1020304050607080"

test_enc = "y+In4kriw0qy4lji6/x14g=="
enc = base64.b64decode(test_enc)

cipher = AES.new(derived_key, AES.MODE_CBC, iv.encode('utf-8'))

print(base64.b64decode(cipher.decrypt(enc)))

print(unpad(cipher.decrypt(enc),16))

这里的任何指导将不胜感激，因为我被困了很长一段时间。

（我使用密码进行加密，但在 HKDF 上苦苦挣扎）。

编辑：

这是完整的 Python 代码：

from cryptography.hazmat.primitives.asymmetric import ec
from cryptography.hazmat.primitives.kdf.hkdf import HKDF
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives import serialization
import base64


from Crypto.Cipher import AES
from Crypto.Util.Padding import pad,unpad


def deriveKey():

  server_pkcs8 = b'''-----BEGIN PRIVATE KEY-----
MIG2AgEAMBAGByqGSM49AgEGBSuBBAAiBIGeMIGbAgEBBDBReGpDVmoVTzxNbJx6
aL4L9z1EdB91eonAmAw7mKDocLfCJITXZPUAmM46c6AipTmhZANiAAR3t96P0ZhU
jtW3rHkHpeGu4e+YT+ufMiMeanE/w8p+d9aCslvIbZyBBzeZ/266yqTUUoiYDzqv
Hb5q8rz7vEgr3DG4XfHYpCqfE2nttQGK3emHKGnvY239AteZkdwMpcs=
-----END PRIVATE KEY-----'''

  client_x509 = b'''-----BEGIN PUBLIC KEY-----
MHYwEAYHKoZIzj0CAQYFK4EEACIDYgAEm0xeyy3nVnYpOpx/CV/FnlNEdWUZaqtB
AGf7flKxXEjmlSUjseYzCd566sLpNg56Gw6hcFx+rWTLGR4eDRWfmwlXhyUasuEg
mb0BQf8XJLBdvadb9eFx2CP1yjBsiy8e
-----END PUBLIC KEY-----'''

  client_public_key = serialization.load_pem_public_key(client_x509)
  server_private_key = serialization.load_pem_private_key(server_pkcs8, password=None)
  shared_secret = server_private_key.exchange(ec.ECDH(), client_public_key)
  print('Shared secret: ' + base64.b64encode(shared_secret).decode('utf8')) # Shared secret: xbU6oDHMTYj3O71liM5KEJof3/0P4HlHJ28k7qtdqU/36llCizIlOWXtj8v+IngF

  salt_bytes = "12345678".encode('utf-8')
  info_bytes = "abc".encode('utf-8')

  derived_key = HKDF(
    algorithm=hashes.SHA256(),
    length=32,
    salt=salt_bytes,
    info=info_bytes,
  ).derive(shared_secret)
  print('Derived key:   ' + base64.b64encode(derived_key).decode('utf8'))
  return derived_key

derived_key = deriveKey()
iv = "1020304050607080"

test_enc = "y+In4kriw0qy4lji6/x14g=="
enc = base64.b64decode(test_enc)

cipher = AES.new(derived_key, AES.MODE_CBC, iv.encode('utf-8'))

print(base64.b64decode(cipher.decrypt(enc)))

print(unpad(cipher.decrypt(enc),16))

Answer 1

问题是密钥没有在 CryptoJS 代码中正确传递。

发布的 Python 代码生成 LefjQ2pEXmiy/nNZvEJ43i8hJuaAnzbA1Cbn1hOuAgA= 作为 Base64 编码的密钥。这必须使用 Base64 编码器:

在 CryptoJS 代码中导入

const payload = "hello"
var derived_key = CryptoJS.enc.Base64.parse("LefjQ2pEXmiy/nNZvEJ43i8hJuaAnzbA1Cbn1hOuAgA=")
var iv = CryptoJS.enc.Utf8.parse("1020304050607080");
var test = CryptoJS.AES.encrypt(payload, derived_key, {iv: iv, mode: CryptoJS.mode.CBC}).toString();
document.getElementById("ct").innerHTML = test; // bLdmGA+HLLyFEVtBEuCzVg==

<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/4.1.1/crypto-js.min.js"></script>
<p style="font-family:'Courier New', monospace;" id="ct"></p>

特此生成的密文bLdmGA+HLLyFEVtBEuCzVg==可以用Python密码解密：

from Crypto.Cipher import AES
from Crypto.Util.Padding import unpad
import base64

test_enc = "bLdmGA+HLLyFEVtBEuCzVg=="
enc = base64.b64decode(test_enc)
derived_key = base64.b64decode("LefjQ2pEXmiy/nNZvEJ43i8hJuaAnzbA1Cbn1hOuAgA=")
iv = "1020304050607080"
cipher = AES.new(derived_key, AES.MODE_CBC, iv.encode('utf-8'))
print(unpad(cipher.decrypt(enc),16)) # b'hello'

请注意，出于安全原因，不应使用静态 IV，这样 key/IV 对就不会重复。

使用 HKDF 密钥的 Crypto-js 加密和 Python 解密

Crypto-js encryption and Python decryption using HKDF key

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python

encryption

cryptography

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