c# - 在 c# 中使用 ---PUBLIC KEY--- 验证 JWT (ES256) token

Question

我有一个由我的 AWS ALB 使用 OpenID 连接器创建的 JWT。我需要在我的 c# 应用程序中验证 token 。但我很难让它发挥作用。

AWS 在此处描述了 token 验证:https://docs.aws.amazon.com/elasticloadbalancing/latest/application/listener-authenticate-users.html?icmpid=docs_elbv2_console

它应该分 3 个步骤工作:

从 token 中获取 key ID

从 aws alb 端点读取公钥 (https://public-keys.auth.elb.' + region + '.amazonaws.com/' + key id)

使用 key

解密有效负载

这是我得到的 JWT:

eyJ0eXAiOiJKV1QiLCJraWQiOiJjODE4ZTcxNi01OTAxLTQzOWQtOWFlZC1lYmRmODAyYjZkYTkiLCJhbGciOiJFUzI1NiIsImlzcyI6Imh0dHBzOi8vc2llbWVucy1xYS0wMDA2OS5ldS5hdXRoMC5jb20vIiwiY2xpZW50IjoiMndsS3k0YlRXbGpZWm9KYXZRSVFqVTE3OUprVG4zNDAiLCJzaWduZXIiOiJhcm46YXdzOmVsYXN0aWNsb2FkYmFsYW5jaW5nOmV1LWNlbnRyYWwtMTo0ODU2ODM0ODcxOTY6bG9hZGJhbGFuY2VyL2FwcC9maW5kLXRlc3QtYWxiLzU3YzBmMWYzZjg0YzZjMjEiLCJleHAiOjE1NzU1NDMwMzN9.eyJzdWIiOiJvYXV0aDJ8bWFpbi10ZW5hbnQtb2lkY3xzYW1scHxTaWVtZW5zfFowMDJFSk5VIiwiZ2l2ZW5fbmFtZSI6IlJhcGhhZWwiLCJmYW1pbHlfbmFtZSI6IlNjaG5haXRsIiwibmlja25hbWUiOiJSYXBoYWVsIiwibmFtZSI6IlJhcGhhZWwgU2NobmFpdGwiLCJwaWN0dXJlIjoiaHR0cHM6Ly9zLmdyYXZhdGFyLmNvbS9hdmF0YXIvODkzNWVlY2QzMDc2ZTAyMTQ5ODE2MTZmZjBkZTRkZjI_cz00ODAmcj1wZyZkPWh0dHBzJTNBJTJGJTJGY2RuLmF1dGgwLmNvbSUyRmF2YXRhcnMlMkZyYS5wbmciLCJ1cGRhdGVkX2F0IjoiMjAxOS0xMi0wNVQxMDo0ODozMy4wNjhaIiwiZXhwIjoxNTc1NTQzMDMzLCJpc3MiOiJodHRwczovL3NpZW1lbnMtcWEtMDAwNjkuZXUuYXV0aDAuY29tLyJ9.M39aPefXmaDGzaDd0qHcQHMhvugTVN4i4pyvGJ-7fayewU9vZdtKvSzFF9rVal8GEz7HKTr_auqMw9HemOWyag==

因此， key ID 是: c818e716-5901-439d-9aed-ebdf802b6da9
公钥:

-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAENARdEGaEpfgHph3440UodVsQdqxi
PYz+l1aEcz+Bivr6emXDnor1nET94dbPqYxk+vtUHGkgOb44VPEZUe4ijQ==
-----END PUBLIC KEY-----

我尝试使用以下方法验证代码:

使用 System.IdentityModel.Tokens.Jwt命名空间。但是我无法将公钥作为字符串提供给 ValidationParameters。我遵循了这个答案的类似方法 https://stackoverflow.com/a/51866939/2250672 .感觉很复杂而且容易出错。由于一整天后我无法让它工作，我决定继续使用提供相同功能的 nuget 软件包之一。

使用 JWT nuget 包，但它不支持 AWS ALB 使用的算法。

使用 Jose.JWT nuget 包使用以下代码:

Jose.JWT.Decode(__token, publicKeyPem, Jose.JwsAlgorithm.ES256)
收到以下错误:

ERROR: Script execution failed. [ArgumentException] EcdsaUsingSha algorithm expects key to be of either CngKey or ECDsa types.

如何在 C# 中简单地从 AWS ALB 验证 JWT？

Answer 1

公钥在 https://siemens-qa-00069.eu.auth0.com/.well-known/openid-configuration 上不可用.因此，您可以尝试手动方法:

    private static ECDsa LoadPublicKey(byte[] key)
    {
        byte[] pubKeyX = key.Skip(27).Take(32).ToArray();
        byte[] pubKeyY = key.Skip(59).Take(32).ToArray();
        return ECDsa.Create(new ECParameters
        {
            Curve = ECCurve.NamedCurves.nistP256,
            Q = new ECPoint
            {
                X = pubKeyX,
                Y = pubKeyY
            }
        });
    }

        string key = "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAENARdEGaEpfgHph3440UodVsQdqxiPYz+l1aEcz+Bivr6emXDnor1nET94dbPqYxk+vtUHGkgOb44VPEZUe4ijQ==";
        ECDsa ecdsa = LoadPublicKey(Convert.FromBase64String(key));
        string authorizationDomain = "https://siemens-qa-00069.eu.auth0.com/";
        string jwt = "eyJ0eXAiOiJKV1QiLCJraWQiOiJjODE4ZTcxNi01OTAxLTQzOWQtOWFlZC1lYmRmODAyYjZkYTkiLCJhbGciOiJFUzI1NiIsImlzcyI6Imh0dHBzOi8vc2llbWVucy1xYS0wMDA2OS5ldS5hdXRoMC5jb20vIiwiY2xpZW50IjoiMndsS3k0YlRXbGpZWm9KYXZRSVFqVTE3OUprVG4zNDAiLCJzaWduZXIiOiJhcm46YXdzOmVsYXN0aWNsb2FkYmFsYW5jaW5nOmV1LWNlbnRyYWwtMTo0ODU2ODM0ODcxOTY6bG9hZGJhbGFuY2VyL2FwcC9maW5kLXRlc3QtYWxiLzU3YzBmMWYzZjg0YzZjMjEiLCJleHAiOjE1NzU1NDMwMzN9.eyJzdWIiOiJvYXV0aDJ8bWFpbi10ZW5hbnQtb2lkY3xzYW1scHxTaWVtZW5zfFowMDJFSk5VIiwiZ2l2ZW5fbmFtZSI6IlJhcGhhZWwiLCJmYW1pbHlfbmFtZSI6IlNjaG5haXRsIiwibmlja25hbWUiOiJSYXBoYWVsIiwibmFtZSI6IlJhcGhhZWwgU2NobmFpdGwiLCJwaWN0dXJlIjoiaHR0cHM6Ly9zLmdyYXZhdGFyLmNvbS9hdmF0YXIvODkzNWVlY2QzMDc2ZTAyMTQ5ODE2MTZmZjBkZTRkZjI_cz00ODAmcj1wZyZkPWh0dHBzJTNBJTJGJTJGY2RuLmF1dGgwLmNvbSUyRmF2YXRhcnMlMkZyYS5wbmciLCJ1cGRhdGVkX2F0IjoiMjAxOS0xMi0wNVQxMDo0ODozMy4wNjhaIiwiZXhwIjoxNTc1NTQzMDMzLCJpc3MiOiJodHRwczovL3NpZW1lbnMtcWEtMDAwNjkuZXUuYXV0aDAuY29tLyJ9.M39aPefXmaDGzaDd0qHcQHMhvugTVN4i4pyvGJ-7fayewU9vZdtKvSzFF9rVal8GEz7HKTr_auqMw9HemOWyag==";
        TokenValidationParameters tokenValidationParameters = new TokenValidationParameters
        {
            ValidIssuer = authorizationDomain,
            ValidateAudience = false,
            IssuerSigningKey = new ECDsaSecurityKey(ecdsa)
        };
        try
        {
            JwtSecurityTokenHandler jwtSecurityTokenHandler = new JwtSecurityTokenHandler();
            jwtSecurityTokenHandler.ValidateToken(jwt, tokenValidationParameters, out _);
            return true;
        }
        catch (SecurityTokenException)
        {
            return false;
        }

问题是我无法测试它，因为在我的机器上(Windows 10 + .NET Core 2.1)我收到这个错误:

System.PlatformNotSupportedException: The specified curve 'nistP256' or its parameters are not valid for this platform. ---> Internal.Cryptography.CryptoThrowHelper+WindowsCryptographicException: The parameter is incorrect