c# - 如何使用带有 RSA 私钥的 RS256 对 JWT 进行签名

Question

我正在使用 jose-jwt library并希望使用 RS256 加密算法在 C# 中创建签名的 JWT。我没有密码学方面的经验，所以请原谅我的无知。我在文档中看到以下示例:

var payload = new Dictionary<string, object>()
{
    { "sub", "mr.x@contoso.com" },
    { "exp", 1300819380 }
};

var privateKey=new X509Certificate2("my-key.p12", "password", X509KeyStorageFlags.Exportable | X509KeyStorageFlags.MachineKeySet).PrivateKey as RSACryptoServiceProvider;

string token=Jose.JWT.Encode(payload, privateKey, JwsAlgorithm.RS256);

其中显示了 p12 文件的使用，但我如何使用以下形式的 RSA key 文件？我正在查看 X509Certificate2 的文档，但我看不到 RSA 私钥的选项。它似乎只接受 PKCS7，据我所知这是公钥。

-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

最后，docs中列出的两个选项有什么区别？ ，我该如何在两者之间做出选择？

-------------------------- OPTION 1 --------------------------

RS-* and PS-* family

CLR:

RS256, RS384, RS512 and PS256, PS384, PS512 signatures require RSACryptoServiceProvider (usually private) key of corresponding length. CSP need to be forced to use Microsoft Enhanced RSA and AES Cryptographic Provider. Which usually can be done be re-importing RSAParameters. See http://clrsecurity.codeplex.com/discussions/243156 for details.

-------------------------- OPTION 2 --------------------------

CORECLR: RS256, RS384, RS512 signatures require RSA (usually private) key of corresponding length.

Answer 1

我知道这篇文章很旧，但我花了很长时间才弄明白，所以我想分享一下。

为了测试，我使用 OpenSSL 创建了 RSA key :

openssl genrsa -out privateKey.pem 512
openssl rsa -in privateKey.pem -pubout -out publicKey.pem

您将需要以下 2 个 nuget 包:

1. https://github.com/dvsekhvalnov/jose-jwt
2. http://www.bouncycastle.org/csharp/

测试代码

public static void Test()
{
        string publicKey = File.ReadAllText(@"W:\Dev\Temp\rsa_keys\publicKey.pem");
        string privateKey = File.ReadAllText(@"W:\Dev\Temp\rsa_keys\privateKey.pem");
        
        var claims = new List<Claim>();
        claims.Add(new Claim("claim1", "value1"));
        claims.Add(new Claim("claim2", "value2"));
        claims.Add(new Claim("claim3", "value3"));

        var token = CreateToken(claims, privateKey);
        var payload = DecodeToken(token, publicKey);
}

创建代币

public static string CreateToken(List<Claim> claims, string privateRsaKey)
{
     RSAParameters rsaParams;
     using (var tr = new StringReader(privateRsaKey))
     {
          var pemReader = new PemReader(tr);
          var keyPair = pemReader.ReadObject() as AsymmetricCipherKeyPair;
          if (keyPair == null)
          {
               throw new Exception("Could not read RSA private key");
          } 
          var privateRsaParams = keyPair.Private as RsaPrivateCrtKeyParameters;
          rsaParams = DotNetUtilities.ToRSAParameters(privateRsaParams);
     }
     using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())
     {
          rsa.ImportParameters(rsaParams);
          Dictionary<string, object> payload = claims.ToDictionary(k => k.Type, v => (object)v.Value);
          return Jose.JWT.Encode(payload, rsa, Jose.JwsAlgorithm.RS256);
     }
}

解码 token

public static string DecodeToken(string token, string publicRsaKey)
{
     RSAParameters rsaParams;

     using (var tr = new StringReader(publicRsaKey))
     {
          var pemReader = new PemReader(tr);
          var publicKeyParams = pemReader.ReadObject() as RsaKeyParameters;
          if (publicKeyParams == null)
          {
               throw new Exception("Could not read RSA public key");
          }
          rsaParams = DotNetUtilities.ToRSAParameters(publicKeyParams);
     }
     using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())
     {
          rsa.ImportParameters(rsaParams);
          // This will throw if the signature is invalid
          return Jose.JWT.Decode(token, rsa, Jose.JwsAlgorithm.RS256);  
     }
}

我找到了 https://jwt.io/一个很好的资源来测试你的代币