Azure Service Bus Shared Access Signature Generation

Question

I am trying to generate Shared Access signature for the Azure service bus queue. Here is the code snippnet through which I am generating SAS token.

using System;
using System.Globalization;
using System.Security.Cryptography;
using System.Text;
using System.Web;

namespace SASTokenGeneration
{
    class Program
    {
        static void Main(string[] args)
        {
            string resourceUri = "sb://xxxservicequeue.servicebus.windows.net/;SharedAccessKeyName=xxxservicequeue;SharedAccessKey=xxxxxx";
            string key = "token";
            string keyName = "xxxservicequeue";
            try
            {
                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(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);

            }
            catch (Exception ex)
            {

            }
        }
    }
}

When I use this token in postman then sometime it gives

MalformedToken: Failed to parse simple web token. azure sevice Bus

and Now I am getting

401 40103: Invalid authorization token signature

From error, I know that I am doing something wrong with connection string but cannot figure out what. Can you please point me in right direction. Thanks

Instead of sharing the screenshot of the code, please paste the actual code. — Gaurav Mantri

Jerry Liu Jerry Liu · Accepted Answer · 2019-01-25T08:05:11

Problems may locate at

string resourceUri = "sb://xxxservicequeue.servicebus.windows.net/;SharedAccessKeyName=xxxservicequeue;SharedAccessKey=xxxxxx";
string key = "token";
string keyName = "xxxservicequeue";

The resourceUri is the full URI of the Service Bus resource to which access is claimed, in the format of sb://xxxservicequeue.servicebus.windows.net/ or with specific entity you need to operate like sb://xxxservicequeue.servicebus.windows.net/queueName.

The key should be the value of SharedAccessKeyKey and keyName is SAS policy name like the default RootManageSharedAccessKey.

Have a look at doc for more details.

Azure Service Bus Shared Access Signature Generation

1 Answers