using System;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        byte[] time = BitConverter.GetBytes(DateTime.UtcNow.ToBinary());

        byte[] key = Guid.NewGuid().ToByteArray();

        string token = Convert.ToBase64String(time.Concat(key).ToArray());      

        Console.WriteLine(token);

    }

}