using System;

using System.Security.Cryptography;

public class Program

{

    public static void Main()

    {

        var g = new Guid("00000000-0000-0000-0000-000000000000");

        Console.WriteLine(g);

        Console.WriteLine(HashApiKey(g));

    }

    private static string HashApiKey(Guid apiKey)

    {

      byte[] byteArray = apiKey.ToByteArray();

      using (SHA256Managed shA256Managed = new SHA256Managed())

        return Convert.ToBase64String(shA256Managed.ComputeHash(byteArray));

    }

}