ES 512 jwt 令牌验证

Question

我正在尝试使用 public 字符串格式的密钥来验证 ES512 jwt 令牌：

我正在尝试模仿为 ES256 编写的示例是这样的：

    // The code for ES256
    public static void VerifyES512Jwt(string token,string publicKey)
    {
        byte[] publicKeyBytes = Convert.FromBase64String(publicKey);

        string[] parts = token.Split('.');

        string header = parts[0];
        string payload = parts[1];
        string signature = parts[2];

        var keyType = new byte[] { 0x45, 0x43, 0x53, 0x31 };
        var keyLength = new byte[] { 0x20, 0x00, 0x00, 0x00 };
        var key = keyType.Concat(keyLength).Concat(publicKeyBytes.Skip(publicKeyBytes.Length - 64)).ToArray(); 
        CngKey cngKey = CngKey.Import(key, CngKeyBlobFormat.EccPublicBlob);
        
        // the purpose is to get ECDsaCng and verify the payload data
         ECDsaCng eCDsaCng = new ECDsaCng(cngKey);
        
        bool result = eCDsaCng.VerifyData(payload, signatureBytes); 
    }

我正在尝试将此代码用于 ES512，但在获取密钥时卡住了

        var keyType = new byte[] { 0x45, 0x43, 0x53, 0x31 };
        var keyLength = new byte[] { 0x20, 0x00, 0x00, 0x00 };
        var key = keyType.Concat(keyLength).Concat(publicKeyBytes.Skip(publicKeyBytes.Length - 64)).ToArray();

当与上面一起使用时，它会在获取密钥时出错：

CngKey cngKey = CngKey.Import(key, CngKeyBlobFormat.EccPublicBlob);

我使用的public密钥和令牌如下： public 键：

MIGbMBAGByqGSM49AgEGBSuBBAAjA4GGAAQBgc4HZz+/fBbC7lmEww0AO3NK9wVZ PDZ0VEnsaUFLEYpTzb90nITtJUcPUbvOsdZIZ1Q8fnbquAYgxXL5UgHMoywAib47 6MkyyYgPk0BXZq3mq4zImTRNuaU9slj9TVJ3ScT3L1bXwVuPJDzpr5GOFpaj+WwM Al8G7CqwoJOsW7Kddns=

令牌：

eyJ0eXAiOiJKV1QiLCJhbGciOiJFUzUxMiJ9.eyJpc3MiOiJPbmxpbmUgSldUIEJ1aWxkZXIiLCJpYXQiOjE1NjUwOTk2ODgsImV4cCI6MTU5ODE4OTg4NSwiYXVkIjoiaHR0cDovL2xvY2FsaG9zdDozNTg4Iiwic3ViIjoiaHR0cDovL2xvY2FsaG9zdDo1MDM3NiIsImZpcnN0bmFtZSI6IkFydmluZCIsImxhc3RuYW1lIjoiS3VtYXIiLCJFbWFpbCI6ImFydmluZC5rdW1hckBzdHJlYW1hbWcuY29tIiwiSWQiOiIxMDEifQ.AVwAJeY44lKrnywnDs7CdUOu3gli2cGafSJ6iP3zT7lkZpd2QnL0k54aVmPVxAGuN5dDnzbYmMTdRl5u2QE92ccOAHrcf5yA2gsvhhAGuDAAeh6Io4VU7v5TOTvwWGRb-ubgdjUvagA_HSJOyeXvFR16_M_MzGfDnXfg02sj4y9VFjDr

Answer 1

ES512 将 ECDSA 与 P-521 和 SHA-512 结合使用。

P-521 的 public 键 (secp521r1, chap. 2.6.1) has a size of 2 x 66 = 132 bytes in uncompressed form (front byte 0x04). MS specifies the public key for P-521 with the value 0x35534345.

因此必须按如下方式生成密钥：

var keyType = new byte[] { 0x45, 0x43, 0x53, 0x35 };
var keyLength = new byte[] { 0x42, 0x00, 0x00, 0x00 };
var key = keyType.Concat(keyLength).Concat(publicKeyBytes.Skip(publicKeyBytes.Length - 132)).ToArray();

要签名的数据是header和有效负载（均为Base64url编码）包括分隔符（.）。签名也是 Base64url 编码的。因此必须按如下方式执行验证：

byte[] headerPayloadBytes = Encoding.UTF8.GetBytes(header + "." + payload);
byte[] signatureBytes = Base64UrlDecode(signature);
bool verified = eCDsaCng.VerifyData(headerPayloadBytes, signatureBytes, HashAlgorithmName.SHA512);

Base64UrlDecode 完成 Base64url 解码，参见例如here 了解实施细节。

Answer 2

我按照@Topaco 的建议生成了密钥，并将其与身份模型的 JwtSecurityTokenHandler 一起使用，并且成功了。由于某些原因，我尝试使用的功能无法正常工作：工作代码如下：

public static bool ValidateEcdsa512JwtToken(string token, string publicKey)
{
    ECDsa pubKey = LoadPublicKey(publicKey);

    var securityTokenHandler = new JwtSecurityTokenHandler();
    var validationParameters = new TokenValidationParameters()
    {
        ValidateAudience = false,
        ValidateIssuer = false,
        IssuerSigningKey = new ECDsaSecurityKey(pubKey)
    };

    SecurityToken stoken;
    var claims = securityTokenHandler.ValidateToken(token, validationParameters, out stoken);
    var verified=claims.Identity.IsAuthenticated;

    return verified;
}


private static ECDsa LoadPublicKey(string publicKey)
{
     byte[] publicKeyBytes = Convert.FromBase64String(publicKey);
     var keyType = new byte[] { 0x45, 0x43, 0x53, 0x35 };
     var keyLength = new byte[] { 0x42, 0x00, 0x00, 0x00 };
     var key = keyType.Concat(keyLength).Concat(publicKeyBytes.Skip(publicKeyBytes.Length - 132)).ToArray();

     CngKey cngKey = CngKey.Import(key, CngKeyBlobFormat.EccPublicBlob);
     ECDsaCng eCDsaCng = new ECDsaCng(cngKey);
     eCDsaCng.HashAlgorithm = CngAlgorithm.ECDsaP521;
     return eCDsaCng;
}

ES 512 jwt 令牌验证

ES 512 jwt token verification

c#

elliptic-curve

ecdsa

jwt-auth