using System;

using System.Security.Cryptography;

​

public class Program

{

    public static void Main()

    {

        //USAePay Basic Auth Header builder in c#

        //set seed

        var seed = "abcdefghijklmnop";

        //set pin

        var apiPin = "123456";

        //set api key

        var apiKey = "_V87Qtb513Cd3vabM7RC0TbtJWeSo8p7";

        //value to hash

        var valueToHash = string.Format("{0}{1}{2}", apiKey, seed, apiPin);

        //hash the value, this returns a byte array

        var hashedValueBytes = (new SHA256Managed()).ComputeHash(System.Text.Encoding.UTF8.GetBytes(valueToHash));

        //take byte array and convert to hex, make lowercase and remove the dashes

        var hashedHex = BitConverter.ToString(hashedValueBytes).Replace("-", "").ToLower();

        //format the seed and hashed value

        var apiHash = string.Format("s2/{0}/{1}", seed, hashedHex);

        //format the header with the hashed value

        var authHeader = string.Format("{0}:{1}", apiKey, apiHash);

        //convert the value to bytes, so we can convert to base64

        var authHeaderBytes = System.Text.Encoding.UTF8.GetBytes(authHeader);

        //convert bytes to base64

        var authHeaderBase64 = Convert.ToBase64String(authHeaderBytes);

        //format the complete header

        var completeHeader = string.Format("Authorization: Basic {0}", authHeaderBase64);

        //print to screen

        Console.WriteLine(completeHeader);

    }

}