using System;

using System.Security.Cryptography;

using System.IdentityModel.Tokens.Jwt;

using System.Security.Claims;

using System.Text;

using Microsoft.IdentityModel.Tokens;

using Microsoft.IdentityModel.Logging;

​

​

// Generate a JWT Token

// https://jwt.io/ - to decode your JWT token

public class Program

{

    public static void Main()

    {

         string userId = "abcdefg";

         var key = Encoding.ASCII.GetBytes("TransCosmosSecretKey");

         var base64SecretKey = Encoding.ASCII.GetBytes(Convert.ToBase64String(key));

         IdentityModelEventSource.ShowPII = true;

         var token = Encoded(userId, base64SecretKey);

         Console.Write("Token : " + token);

    }

​

    public static string Encoded(string userId, byte[] secretKey)

    {

        var securityKey = new SymmetricSecurityKey(secretKey);

        var credentials = new SigningCredentials(securityKey, SecurityAlgorithms.HmacSha256);

        var header = new JwtHeader(credentials);

        var payload = new JwtPayload

        {

            { "userid", userId},

        };

        var secToken = new JwtSecurityToken(header, payload);

        var handler = new JwtSecurityTokenHandler();

​

        var tokenString = handler.WriteToken(secToken);

​

        return tokenString;

    }

    public static string GenerateKey()

    {

        var secret = new HMACSHA256();

        var symmetricKey = Convert.ToBase64String(secret.Key);

        return symmetricKey;

    }

    public static string GenerateToken(string userId, string firstname, string lastname, string email, int expireMinutes = 5, string overrideKey = "")

    {

        var key = "";

        if(!string.IsNullOrWhiteSpace(overrideKey))

        {

            key = overrideKey;

        }

        else

        {

            key = GenerateKey();

        }   

​

        //var symmetricKey = Convert.FromBase64String(key);

        var symmetricKey = Encoding.UTF8.GetBytes(key);

        var tokenHandler = new JwtSecurityTokenHandler();

​

        var now = DateTime.UtcNow;

        var tokenDescriptor = new SecurityTokenDescriptor

        { 

            Subject = new ClaimsIdentity(new[]

                    {

                        new Claim("sub", email),

                        new Claim("first_name", firstname),

                        new Claim("last_name", lastname),

                        new Claim("member_id", userId)

                    }),

            Expires = now.AddMinutes(expireMinutes),

            SigningCredentials = new SigningCredentials(new SymmetricSecurityKey(symmetricKey), SecurityAlgorithms.HmacSha256Signature)

        };

​

        var stoken = tokenHandler.CreateToken(tokenDescriptor);

        var token = tokenHandler.WriteToken(stoken);

​

        return token;

    }

    public static string Encode(byte[] data)

        {

            if (data == null)

            {

                throw new ArgumentNullException("data");

            }

​

            return Convert.ToBase64String(data).TrimEnd('=').Replace('+', '-').Replace('/', '_');

        }

​

        public static byte[] Decode(string text)

        {

            if (text == null)

            {

                throw new ArgumentNullException("text");

            }

​

            return Convert.FromBase64String(Pad(text.Replace('-', '+').Replace('_', '/')));

        }

​

        private static string Pad(string text)

        {

            var padding = 3 - ((text.Length + 3) % 4);

            if (padding == 0)

            {

                return text;

            }

            return text + new string('=', padding);

        }

}