using System;

using System.Text;

using System.Security.Cryptography;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        //var requestContent = "{\"Amount\":\"10\",\"Currency\" :\"NGN\",\"ExternalTxId\" :\"007\",\"PaymentMethod\" :\"PaymentMethod\",\"UserId\" :\"359797\"}";

        var requestContent = "{ UserId:\"359704\" }";

        var result = objectHashBase64(Regex.Replace(requestContent, @"\s+", ""), "xuU6Hxq9yxV9F2U");

        Console.WriteLine("Content: " + requestContent);

        Console.WriteLine("");

        Console.WriteLine("Security Hash: " + result);      

    }

    private static string objectHashBase64 (string clearString, string salt)

    {

        var clearStringBytes = Encoding.UTF8.GetBytes(clearString);

        var sharedKeyBytes = Encoding.UTF8.GetBytes(salt);

        byte[] plainTextWithSaltBytes = new byte[clearStringBytes.Length + sharedKeyBytes.Length];      

        for (int i = 0; i < clearStringBytes.Length; i++)

            plainTextWithSaltBytes[i] = clearStringBytes[i];             

        for (int i = 0; i < sharedKeyBytes.Length; i++)

            plainTextWithSaltBytes[clearStringBytes.Length + i] = sharedKeyBytes[i];

        var shaAlgo = SHA512.Create();

        byte[] hashBytes = shaAlgo.ComputeHash(plainTextWithSaltBytes);

        return Convert.ToBase64String(hashBytes);

​

    }  

    //private static string objectHashHex (string clearString, string salt)

    //{

    //  List<byte> bytesString = SHA512.Create().ComputeHash(Encoding.UTF8.GetBytes(clearString + salt)).ToList();

    //        StringBuilder sb = new StringBuilder();

    //        foreach (byte b in bytesString)

    //            sb.Append(b.ToString("x2"));

    //

    //        return sb.ToString();

    //}

​

}