JWT 토큰을 디코딩하는 방법은 무엇입니까?

JWT 토큰을 디코딩하는 방법은 무엇입니까?

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이 라이브러리가 어떻게 작동하는지 이해할 수 없습니다. 제발 도와 주 시겠어요?

다음은 내 간단한 코드입니다.

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

        var jsonToken = handler.ReadToken(stream);
    }

이것은 오류입니다.

문자열은 Base64UrlEncodedHeader.Base64UrlEndcodedPayload.OPTIONAL, Base64UrlEncodedSignature '형식의 압축 JSON 형식이어야합니다.

jwt.io 웹 사이트 에서 스트림을 복사하면 정상적으로 작동합니다. :)

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해결책을 찾았지만 결과를 전송하는 것을 잊었습니다.

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

다음을 사용하여 클레임을받을 수 있습니다.

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

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new JwtSecurityTokenHandler().ReadToken("") 반환합니다 SecurityToken

new JwtSecurityTokenHandler().ReadJwtToken("") 반환합니다 JwtSecurityToken

사용하는 방법을 변경하면 위의 답변에서 캐스트를 피할 수 있습니다.

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암호화 토큰을 생성하는 데 사용 된 비밀 문자열이 필요합니다. 이 코드는 나를 위해 작동합니다.

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;
    }

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.net 코어 jwt 패키지를 사용하면 클레임을 사용할 수 있습니다.

[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;
    }
}

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Extending on cooxkie answer, and dpix answer, when you are reading a jwt token (such as an access_token received from AD FS), you can merge the claims in the jwt token with the claims from "context.AuthenticationTicket.Identity" that might not have the same set of claims as the jwt token.

To Illustrate, in an Authentication Code flow using OpenID Connect,after a user is authenticated, you can handle the event SecurityTokenValidated which provides you with an authentication context, then you can use it to read the access_token as a jwt token, then you can "merge" tokens that are in the access_token with the standard list of claims received as part of the user identity:

    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);
    }

---

  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);

Then extract content

 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;

참고URL : https://stackoverflow.com/questions/38340078/how-to-decode-jwt-token