using System;

using System.Web;

using System.Security.Cryptography;

using System.Text;

using System.Globalization;

​

public class Program

{

    public static void Main()

    {

        string resourceUri = "https://photiaservicebusstaging.servicebus.windows.net/test-topic";

        string key = "Pn4e52xsazKyY6UrycOkb76q6mva9Gptjn6bmDPgiNU=";

        string keyName = "RootManageSharedAccessKey";

        TimeSpan sinceEpoch = DateTime.UtcNow - new DateTime(1970, 1, 1);

        var week = 60 * 60 * 24 * 7;

        var expiry = Convert.ToString((int)sinceEpoch.TotalSeconds + week);

        string stringToSign = HttpUtility.UrlEncode(resourceUri) + "\n" + expiry;

        HMACSHA256 hmac = new HMACSHA256(System.Text.Encoding.UTF8.GetBytes(key));

        var signature = Convert.ToBase64String(hmac.ComputeHash(Encoding.UTF8.GetBytes(stringToSign)));

        var sasToken = String.Format(CultureInfo.InvariantCulture, "SharedAccessSignature sr={0}&sig={1}&se={2}&skn={3}", HttpUtility.UrlEncode(resourceUri), HttpUtility.UrlEncode(signature), expiry, keyName);

​

        Console.WriteLine(sasToken);

    }

}