找不到使用jwcrypto在python (但在ASP.Net中创建)中解密JWE令牌的方法

Question

使用ASP.Net加密后，我在python中解密我的JWE令牌时遇到了困难。

这是我的C#代码(假密码)：

var signingKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes("ae743683f78d498a9026d0c87020b9d3"));
var secret = new SymmetricSecurityKey(Encoding.UTF8.GetBytes("MbPeShVmYq3t6w9z"));

var signingCreds = new SigningCredentials(signingKey, SecurityAlgorithms.HmacSha256);
var encryptingCreds = new EncryptingCredentials(secret, SecurityAlgorithms.Aes128KW, SecurityAlgorithms.Aes128CbcHmacSha256);
var handler = new JwtSecurityTokenHandler();

var jwtSecurityToken = handler.CreateJwtSecurityToken(
    _issuer,
    _audience,
    new ClaimsIdentity(claimsList),
    DateTime.Now,
    _expires,
    DateTime.Now,
    signingCreds,
    encryptingCreds);

var token = handler.WriteToken(jwtSecurityToken);

使用加密凭据时，令牌如下所示( typ不应为JWE?)：

{
    {
        "alg": "A128KW",
        "enc": "A128CBC-HS256",
        "typ": "JWT"
    }.{
        "userId": "151aedd5-76c3-4eb2-8b73-a16004315731",
        "prop1": "test1",
        "prop2": "test2",
        "nbf": 1549894420,
        "exp": 1550240017,
        "iat": 1549894420,
        "iss": "https://localhost:56880/",
        "aud": "https://localhost:56880/"
    }
}

这是加密后的令牌：

eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2IiwidHlwIjoiSldUIn0.4w4MZv5WFALGbXhmaYqtTv1VGrUpQpDJ0jN8VmLpQwDRU0j16RbPyg.hGt_z5j8THCiNEhpVvlJmw.WehLBKdyB_eYtDRvHxJHgYwa4GA7f8oKYf3GgIqAAih1eVqU084kHu1lIhC8ibxxziwmFZ4IhBFT-nWgWQrH9thhgqndF4ojtGRBgdHtW3GDAgYV6fgI11h6meyBBuLBs7mkQC5PX8EYsMTDiNE9iNTH4pWtDElc07CGGXlHsm6ntuq7G3sinagZtZMchy1shTY73NTS40FqW37C9HTIPDbrTdsm-USHcGaBMLSmjF5eOZ9Po3p4fhRT42l_gwJc9tlurttYBucvIiO1r_3NB8xGeORizYW1P_P9XGusAFy4L8h8XU9P0FctsMjUFy64LOIK8Qv8YZVq4q82vv-r9uGH6bApUdpCIcYFfGu86w63t1QLQcDT_OYMCqwo9ZmZP5Gd07lB1ypNZbP6hQTgkosp3js3i4K4bFQY7CiSXB_pSTH623TMLHNfUXWMRMIBHmXGr-zTZiKj5vkVUZLjNg.sdBUYvadnwMhkCXP8sABgA

我尝试了几个不同的python包，包括两个版本的jose (python-jose和jose)，但无法让jose使用加密(似乎不支持A128KW算法)。

我现在正在尝试jwcrypto，但它似乎希望我生成一个新密钥，而不是使用现有的密钥(用于在ASP.Net中加密JWT的密钥)：

from jwcrypto import jwk, jwe

encrypted_token = request.cookies.get(cookie_name)  
private_key = "MbPeShVmYq3t6w9z"

jwk_key = jwk.JWK()

# not sure how to use my existing "private_key" value, 
# and no support for "A128KW" with jwcrypto despite 
# the documentation saying there is support
key = jwk_key.import_key(alg='A128KW', kty="A256CBC-HS512")

jwe_token = jwe.JWE()
jwe_token.deserialize(encrypted_token)
jwe_token.decrypt(key) # decrypt requires an instance of JWK
decrypted_payload = jwe_token.payload

我怎么才能让它工作呢？谢谢你能给我的任何建议。

Answer 1

看起来python-jose不支持JWE。在他们的online documentation或in the source code中，我找不到任何与JWE解析或加密/解密相关的代码行。

希望在jwt.io的库列表中，我已经找到了应该支持这种加密令牌的jwcrypto (参见this example dealing with A256KW)，并且在源代码中我们可以看到A128KW is listed。

你可以试一试。

from jwcrypto import jwk, jwe

encrypted_token = request.cookies.get(cookie_name)  

key = jwk.JWK.from_json('{"kty":"oct","k":"TWJQZVNoVm1ZcTN0Nnc5eg"}')

jwe_token = jwe.JWE()
jwe_token.deserialize(encrypted_token)
jwe_token.decrypt(key)
decrypted_payload = jwe_token.payload