title: Get custom claims from a JWT using Owin
body: <p>I'm using Owin with JWTBearerAuthentication to authorize users and validate their tokens. I'm doing it like this:</p>
  
  <pre><code>public class Startup
  {
      public void Configuration(IAppBuilder app)
      {
          HttpConfiguration config = new HttpConfiguration();
          config.MapHttpAttributeRoutes();
  
          config.Routes.MapHttpRoute(
              name: "DefaultApi",
              routeTemplate: "api/{controller}/{id}",
              defaults: new { id = RouteParameter.Optional }
          );
  
          ConfigureOAuth(app);
          app.UseWebApi(config);
      }
  
      private void ConfigureOAuth(IAppBuilder app)
      {
          string issuer = ConfigurationManager.AppSettings.Get("auth_issuer");
          string audience = ConfigurationManager.AppSettings.Get("auth_clientId");
          byte[] secret = TextEncodings.Base64Url.Decode(ConfigurationManager.AppSettings.Get("auth_secret"));
  
          app.UseJwtBearerAuthentication(new JwtBearerAuthenticationOptions 
          {
              AuthenticationMode = AuthenticationMode.Active,
              AllowedAudiences = new [] { audience },
              IssuerSecurityTokenProviders = new IIssuerSecurityTokenProvider[]
              {
                  new SymmetricKeyIssuerSecurityTokenProvider(issuer, secret)
              }
          });
      }
  }
  </code></pre>
  
  <p>However, I have some custom claims in my token, and want to use their values in my ApiController, which looks like this:</p>
  
  <pre><code>[RoutePrefix("endpoint")]
  public class MyApiController : ApiController
  {
      [Route("action")]
      [Authorize]
      public IHttpActionResult Post(string someValue)
      {
          bool res = DoSomeAction.withTheString(someValue);
  
          if (res)
          {
              return Ok&lt;string&gt;(someValue);
          }
  
          return InternalServerError();
      }
  }
  </code></pre>
  
  <p>Is there anything like <code>User.Claims["myCustomClaim"].Value</code>, which provides the values of all claims?</p>
  
  <p>Thank you,
  Lukas</p>