using System;

using System.Web;   

using System.Text;

using System.Security.Cryptography;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        byte[] hash = getSha256("1646:8ede3bef-6f5f-4814-91f3-4451783ac2a0");

        string hashString = string.Join("", hash.Select(b => string.Format("{0:x2}", b)));

        Console.WriteLine(hashString);

        var encoded = HttpServerUtility.UrlTokenEncode(hash);

        Console.WriteLine(encoded);

    }

    public static byte[] getSha256(string text)

    {

        byte[] bytes = Encoding.ASCII.GetBytes(text);

        SHA256Managed hashstring = new SHA256Managed();

        return hashstring.ComputeHash(bytes);

    }

    //public static string getHashSha256(string text)

    //{

    //    byte[] bytes = Encoding.ASCII.GetBytes(text);

    //    SHA256Managed hashstring = new SHA256Managed();

    //    byte[] hash = hashstring.ComputeHash(bytes);

    //    string hashString = string.Empty;

    //    foreach (byte x in hash)

    //    {

    //        hashString += String.Format("{0:x2}", x);

    //    }

    //    return hashString;

    //}

}