如何解码 JWT 令牌？

Question

我不明白这个库是如何工作的。你能帮帮我吗？

这是我的简单代码：

public void TestJwtSecurityTokenHandler()
    {
        var stream =
            "eyJhbGciOiJSUzI1NiJ9.eyJpc3MiOiJJU1MiLCJzY29wZSI6Imh0dHBzOi8vbGFyaW0uZG5zY2UuZG91YW5lL2NpZWxzZXJ2aWNlL3dzIiwiYXVkIjoiaHR0cHM6Ly9kb3VhbmUuZmluYW5jZXMuZ291di5mci9vYXV0aDIvdjEiLCJpYXQiOiJcL0RhdGUoMTQ2ODM2MjU5Mzc4NClcLyJ9";
        var handler = new JwtSecurityTokenHandler();

        var jsonToken = handler.ReadToken(stream);
    }

这是错误：

字符串需要采用紧凑的 JSON 格式，格式为：Base64UrlEncodedHeader.Base64UrlEndcodedPayload.OPTIONAL,Base64UrlEncodedSignature'。

如果你复制jwt.io website中的流，它工作正常:)

Answer 1

我找到了解决方案，我只是忘了投射结果：

var stream = "[encoded jwt]";  
var handler = new JwtSecurityTokenHandler();
var jsonToken = handler.ReadToken(stream);
var tokenS = jsonToken as JwtSecurityToken;

或者，没有演员表：

var token = "[encoded jwt]";  
var handler = new JwtSecurityTokenHandler();
var jwtSecurityToken = handler.ReadJwtToken(token);

我可以通过以下方式获得索赔：

var jti = tokenS.Claims.First(claim => claim.Type == "jti").Value;

Answer 2

new JwtSecurityTokenHandler().ReadToken("") 将返回 SecurityToken

new JwtSecurityTokenHandler().ReadJwtToken("") 将返回 JwtSecurityToken

如果您只是更改使用的方法，则可以避免上述答案中的演员表

Answer 3

使用 .net core jwt 包，声明可用：

[Route("api/[controller]")]
[ApiController]
[Authorize(Policy = "Bearer")]
public class AbstractController: ControllerBase
{
    protected string UserId()
    {
        var principal = HttpContext.User;
        if (principal?.Claims != null)
        {
            foreach (var claim in principal.Claims)
            {
               log.Debug($"CLAIM TYPE: {claim.Type}; CLAIM VALUE: {claim.Value}");
            }

        }
        return principal?.Claims?.SingleOrDefault(p => p.Type == "username")?.Value;
    }
}

Answer 4

您需要用于生成加密令牌的秘密字符串。 这段代码对我有用：

protected string GetName(string token)
    {
        string secret = "this is a string used for encrypt and decrypt token"; 
        var key = Encoding.ASCII.GetBytes(secret);
        var handler = new JwtSecurityTokenHandler();
        var validations = new TokenValidationParameters
        {
            ValidateIssuerSigningKey = true,
            IssuerSigningKey = new SymmetricSecurityKey(key),
            ValidateIssuer = false,
            ValidateAudience = false
        };
        var claims = handler.ValidateToken(token, validations, out var tokenSecure);
        return claims.Identity.Name;
    }

Answer 5

在cooxkie 答案和dpix 答案上进行扩展，当您读取 jwt 令牌（例如从 AD FS 接收到的 access_token）时，您可以将 jwt 令牌中的声明与“context.xml”中的声明合并。 AuthenticationTicket.Identity”，可能与 jwt 令牌的声明集不同。

为了说明，在使用 OpenID Connect 的身份验证代码流中，用户通过身份验证后，您可以处理事件SecurityTokenValidated，它为您提供身份验证上下文，然后您可以使用它来读取 access_token 作为 jwt 令牌，然后您可以将 access_token 中的令牌与作为用户身份的一部分接收的标准声明列表“合并”：

    private Task OnSecurityTokenValidated(SecurityTokenValidatedNotification<OpenIdConnectMessage,OpenIdConnectAuthenticationOptions> context)
    {
        //get the current user identity
        ClaimsIdentity claimsIdentity = (ClaimsIdentity)context.AuthenticationTicket.Identity;

        /*read access token from the current context*/
        string access_token = context.ProtocolMessage.AccessToken;

        JwtSecurityTokenHandler hand = new JwtSecurityTokenHandler();
        //read the token as recommended by Coxkie and dpix
        var tokenS = hand.ReadJwtToken(access_token);
        //here, you read the claims from the access token which might have 
        //additional claims needed by your application
        foreach (var claim in tokenS.Claims)
        {
            if (!claimsIdentity.HasClaim(claim.Type, claim.Value))
                claimsIdentity.AddClaim(claim);
        }

        return Task.FromResult(0);
    }

Answer 6

  var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_config["Jwt:Key"]));
  var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
  var claims = new[]
  {
      new Claim(JwtRegisteredClaimNames.Email, model.UserName),
      new Claim(JwtRegisteredClaimNames.NameId, model.Id.ToString()),
  };
  var token = new JwtSecurityToken(_config["Jwt:Issuer"],
      _config["Jwt:Issuer"],
      claims,
      expires: DateTime.Now.AddMinutes(30),
      signingCredentials: creds);

然后提取内容

 var handler = new JwtSecurityTokenHandler();
 string authHeader = Request.Headers["Authorization"];
 authHeader = authHeader.Replace("Bearer ", "");
 var jsonToken = handler.ReadToken(authHeader);
 var tokenS = handler.ReadToken(authHeader) as JwtSecurityToken;
 var id = tokenS.Claims.First(claim => claim.Type == "nameid").Value;

Answer 7

我写了这个解决方案，它对我有用

    protected Dictionary<string, string> GetTokenInfo(string token)
    {
        var TokenInfo = new Dictionary<string, string>();

        var handler = new JwtSecurityTokenHandler();
        var jwtSecurityToken = handler.ReadJwtToken(token);
        var claims = jwtSecurityToken.Claims.ToList();

        foreach (var claim in claims)
        {
            TokenInfo.Add(claim.Type, claim.Value);
        }

        return TokenInfo;
    }