public static Jwt DecodeTokenString(string str)
 {
     string[] arr = str.Split('.');
     return(new Jwt(JsonConvert.DeserializeObject <Header>(Cryptographer.Base64Decode(arr[0])),
                    JsonConvert.DeserializeObject <Payload>(Cryptographer.Base64Decode(arr[1])),
                    arr[2]));
 }