using System;

using System.Security.Cryptography;

using System.Text;

using System.Web;

public class Program

{

    public static void Main()

    {

        string clientKey = "20574";

        string clientPass = "20574";

        string mifareId = "049058CADE3280";

        string saleTransactionId = "1596321";

        //string data = string.Concat(msg.ClientData.clientKey, msg.ClientData.clientPass, msg.MifareId, msg.SaleTransactionId.ToString());

        string data = string.Concat(clientKey, clientPass, mifareId, saleTransactionId);

        SHA1 sha = new SHA1CryptoServiceProvider();

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

        byte[] hashingbytes = sha.ComputeHash(bytes);

        string hash = HttpUtility.UrlEncode(Convert.ToBase64String(hashingbytes));

        Console.WriteLine(hash);

    }

}