using System;

using System.Text;

using System.Security.Cryptography;

​

public class Program

{

    public static byte[] StringToByteArray(String hex)

    {

        int NumberChars = hex.Length;

        byte[] bytes = new byte[NumberChars / 2];

        for (int i = 0; i < NumberChars; i += 2)

            bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);

        return bytes;

    }

    public static string ByteArrayToString(byte[] ba)

    {

        StringBuilder hex = new StringBuilder(ba.Length * 2);

        foreach (byte b in ba)

            hex.AppendFormat("{0:x2}", b);

        return hex.ToString();

    }

​

    public static void Main()

    {

        Console.WriteLine("Expected:");

        Console.WriteLine("740f81cd7deed90102a36e41a74cbe7373856ff647c66d0c945db8c4dfc67130");

​

        string input = "d8818b38a14e7461e87301ad4b9809b558bcbca816b650cd470452e018ada255";

        var serverSeed = StringToByteArray(input);

        Console.WriteLine("Server Seed:");

        Console.WriteLine(ByteArrayToString(serverSeed));

        using (var sha = SHA256.Create())

        {

            var hash = sha.ComputeHash(Encoding.ASCII.GetBytes(input));

            Console.WriteLine("Actual:");

            Console.WriteLine(ByteArrayToString(hash));

            Console.WriteLine("Input in ASCII encoding:");

            Console.WriteLine(ByteArrayToString(Encoding.ASCII.GetBytes(input)));

        }

    }

}