title: GoToWebinar Webhook Signature verification fails
body: <p>I am trying to verify webhook signature for GoToWebinar webinar.created event.</p>
  <p>Docs: <a href="https://developer.goto.com/guides/HowTos/08_HOW_webhooks/" rel="nofollow noreferrer">https://developer.goto.com/guides/HowTos/08_HOW_webhooks/</a></p>
  <p>My Middleware (Laravel):</p>
  <pre><code> public function handle(Request $request, Closure $next)
      {
         
          if (! $this-&gt;verifyGoToWebinarWebhookSignature($request)) {
              abort(401);
          }
  
          return $next($request);
      }
  
      private function verifyGoToWebinarWebhookSignature(Request $request):bool
      {
          return ($request-&gt;header('x-webhook-signature') == $this-&gt;calculateHmac($request));
      }
  
      private function calculateHmac(Request $request):string
      {
          $secret = '12345';
          $signature = $request-&gt;header('x-webhook-signature-timestamp');
          $payload = json_encode($request-&gt;all(), true);
          $signaturePayload = $signature . ':' . $payload;
  
          return base64_encode(hash_hmac('sha256', $signaturePayload, $secret, true));
      }
  </code></pre>
  <p>The comparison always returns false. Tested on real data. Can't figure out what I did wrong.</p>