var payload = new Dictionary<string, object>
{
    { "claim1", 0 },
    { "claim2", "claim2-value" }
};
const string secret = "GQDstcKsx0NHjPOuXOYg5MbeJ1XT0uFiwDVvVBrk";

IJwtAlgorithm algorithm = new HMACSHA256Algorithm();
IJsonSerializer serializer = new JsonNetSerializer();
IBase64UrlEncoder urlEncoder = new JwtBase64UrlEncoder();
IJwtEncoder encoder = new JwtEncoder(algorithm, serializer, urlEncoder);

var token = encoder.Encode(payload, secret);
Console.WriteLine(token);

  var token = new JwtBuilder()
      .WithAlgorithm(new HMACSHA256Algorithm())
      .WithSecret(secret)
      .AddClaim("exp", DateTimeOffset.UtcNow.AddHours(1).ToUnixTimeSeconds())
      .AddClaim("claim2", "claim2-value")
      .Build();

Console.WriteLine(token);

const string token = "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJjbGFpbTEiOjAsImNsYWltMiI6ImNsYWltMi12YWx1ZSJ9.8pwBI_HtXqI3UgQHQ_rDRnSQRxFL1SR8fbQoS-5kM5s";
const string secret = "GQDstcKsx0NHjPOuXOYg5MbeJ1XT0uFiwDVvVBrk";

try
{
    IJsonSerializer serializer = new JsonNetSerializer();
    IDateTimeProvider provider = new UtcDateTimeProvider();
    IJwtValidator validator = new JwtValidator(serializer, provider);
    IBase64UrlEncoder urlEncoder = new JwtBase64UrlEncoder();
    IJwtDecoder decoder = new JwtDecoder(serializer, validator, urlEncoder);
    
    var json = decoder.Decode(token, secret, verify: true);
    Console.WriteLine(json);
}
catch (TokenExpiredException)
{
    Console.WriteLine("Token has expired");
}
catch (SignatureVerificationException)
{
    Console.WriteLine("Token has invalid signature");
}

try
{
    var json = new JwtBuilder()
        .WithSecret(secret)
        .MustVerifySignature()
        .Decode(token);                    
    Console.WriteLine(json);
}
catch (TokenExpiredException)
{
    Console.WriteLine("Token has expired");
}
catch (SignatureVerificationException)
{
    Console.WriteLine("Token has invalid signature");
}

var payload = decoder.DecodeToObject<IDictionary<string, object>>(token, secret);
Console.WriteLine(payload["claim2"]);

var payload = new JwtBuilder()
        .WithSecret(secret)
        .MustVerifySignature()
        .Decode<IDictionary<string, object>>(token);     
Console.WriteLine(payload["claim2"]);

IDateTimeProvider provider = new UtcDateTimeProvider();
var now = provider.GetNow();

var secondsSinceEpoch = UnixEpoch.GetSecondsSince(now);

var payload = new Dictionary<string, object>
{
    { "exp", secondsSinceEpoch }
};
const string secret = "GQDstcKsx0NHjPOuXOYg5MbeJ1XT0uFiwDVvVBrk";
var token = encoder.Encode(payload, secret);

var json = decoder.Decode(token, secret); // throws TokenExpiredException

public class CustomJsonSerializer : IJsonSerializer
{
    public string Serialize(object obj)
    {
        // Implement using favorite JSON serializer
    }

    public T Deserialize<T>(string json)
    {
        // Implement using favorite JSON serializer
    }
}

IJwtAlgorithm algorithm = new HMACSHA256Algorithm();
IJsonSerializer serializer = new CustomJsonSerializer();
IBase64UrlEncoder urlEncoder = new JwtBase64UrlEncoder();
IJwtEncoder encoder = new JwtEncoder(algorithm, serializer, urlEncoder);

JsonSerializer customJsonSerializer = new JsonSerializer
{
    // All keys start with lowercase characters instead of the exact casing of the model/property, e.g. fullName
    ContractResolver = new CamelCasePropertyNamesContractResolver(), 
    
    // Nice and easy to read, but you can also use Formatting.None to reduce the payload size
    Formatting = Formatting.Indented,
    
    // The most appropriate datetime format.
    DateFormatHandling = DateFormatHandling.IsoDateFormat,
    
    // Don't add keys/values when the value is null.
    NullValueHandling = NullValueHandling.Ignore,
    
    // Use the enum string value, not the implicit int value, e.g. "red" for enum Color { Red }
    Converters.Add(new StringEnumConverter())
};
IJsonSerializer serializer = new JsonNetSerializer(customJsonSerializer);

public void ConfigureServices(IServiceCollection services)
{
    services.AddAuthentication(options =>
                 {
                     options.DefaultAuthenticateScheme = JwtAuthenticationDefaults.AuthenticationScheme;
                     options.DefaultChallengeScheme = JwtAuthenticationDefaults.AuthenticationScheme;
                 })
            .AddJwt(options =>
                 {
                     // secrets
                     options.Keys = new[] { "GQDstcKsx0NHjPOuXOYg5MbeJ1XT0uFiwDVvVBrk" };
                     
                     // force JwtDecoder to throw exception if JWT signature is invalid
                     options.VerifySignature = true;
                 });
}

public void Configure(IApplicationBuilder app)
{
    app.UseAuthentication();
}

options.IdentityFactory = dic => new ClaimsIdentity(
    dic.Select(p => new Claim(p.Key, p.Value)));

options.TicketFactory = (identity, scheme) => new AuthenticationTicket(
    new ClaimsPrincipal(identity),
    new AuthenticationProperties(),
    scheme.Name);

app.UseJwtMiddleware();

app.UseJwtMiddleware();