using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Collections;

using System.Text;

using System.Security.Cryptography;

using System.Collections.Specialized;

public class Program

{

    public static void Main()

    {

        String key = "VLrfywNVp94tlsrjrL7Ht8Q/Ni++MCxgn4TI6GKVCGc=";

        String data = "access_key=4a4e752fa7433659a8ec9bc910c04ff0,profile_id=SAWM001,transaction_uuid=b959a9ca-94d0-40ab-879c-871209bc19f2,signed_field_names=access_key,profile_id,transaction_uuid,signed_field_names,unsigned_field_names,signed_date_time,locale,transaction_type,reference_number,amount,currency,req_override_custom_receipt_page,unsigned_field_names=payment_method,echeck_account_type,echeck_routing_number,echeck_account_number,bill_to_forename,bill_to_surname,bill_to_email,bill_to_phone,bill_to_address_line1,bill_to_address_city,bill_to_address_state,bill_to_address_country,bill_to_address_postal_code,signed_date_time=2013-12-12T20:20:14Z,locale=en,transaction_type=create_payment_token,reference_number=sahoptest-0000000002,amount=16.00,currency=USD,req_override_custom_receipt_page=";

        Console.WriteLine("Hello World");

        UTF8Encoding encoding = new System.Text.UTF8Encoding();

        byte[] keyByte = encoding.GetBytes(key);

​

        HMACSHA256 hmacsha256 = new HMACSHA256(keyByte);

        byte[] messageBytes = encoding.GetBytes(data);

        Console.WriteLine("sign :" + Convert.ToBase64String(hmacsha256.ComputeHash(messageBytes)));

    }

}