using System;

using System.Security.Cryptography;

using System.Text;

​

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(GetAuthKey("_1K228P2p425KoE87X0fwBVn69fuEjTd", "2016"));

    }

            private static string GetAuthKey(string apiKey, string apiPin)

        {

            // To create the hash we must concat the sourcekey, seed and pin

            string seed = Guid.NewGuid().ToString();

            string prehash = $"{apiKey}{seed}{apiPin}";

            // Generate the sha256 hash

            var apiHash = $"s2/{seed}/{GetSha256Hash(prehash)}";

​

            var authkey = Convert.ToBase64String(Encoding.UTF8.GetBytes($"{apiKey}:{apiHash}"));

​

            return authkey;

        }

​

        //USAepay, supports only sha256 currently.

        private static string GetSha256Hash(string SourceText)

        {

            // Create a SHA256   

            using (SHA256 sha256Hash = SHA256.Create())

            {

                // ComputeHash - returns byte array  

                byte[] bytes = sha256Hash.ComputeHash(Encoding.UTF8.GetBytes(SourceText));

                // Convert byte array to a string   

                StringBuilder sb = new StringBuilder();

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

                {

                    sb.Append(bytes[i].ToString("x2"));

                }

                return sb.ToString();

            }

        }

}