using System;

using System.Security.Cryptography;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(generateHash("testString", "UTI5dVozSmhkSE1zSUhsdmRTZDJaU0JtYjNWdVpDQnBkQ0VnUVhKbElIbHZkU0J5WldGa2VTQjBieUJxYjJsdUlIVnpQeUJxYjJKelFIZGhiR3hoY0c5d0xtTnZiUT09"));

    }

​

    public static string generateHash(string str, string cypherkey)

    {

        byte[] keyBytes = System.Convert.FromBase64String(cypherkey);

        using (var hmacsha256 = new HMACSHA256(keyBytes))

        {

            byte[] hashmessage = hmacsha256.ComputeHash(System.Text.Encoding.UTF8.GetBytes(str));

            return Convert.ToBase64String(hashmessage);

        }

    }

}