code: function handleValidation(req, res, next) {
        var payload = JSON.stringify(req.body);
        var nodeVersion = Number(process.version.replace(/^v/, '').split(/\./)[0]);
  
        var utf8safe = nodeVersion >= 6 ? payload : unescape(encodeURIComponent(payload));
        var hash = crypto.createHmac('sha1', secret).update(utf8safe).digest('hex');
        var signature = req.get('layer-webhook-signature');
  
        if (hash === signature) next();
        else {
          loggerError('Computed HMAC Signature ' + hash + ' did not match signed header ' + signature + '. Returning Error.  Config:', JSON.stringify(payload.config || {}));
          res.sendStatus(403);
        }
      }
docs: Validate that the request comes from Layer services by comparing the secret
  provided when registering the webhook with the 'layer-webhook-signature' header.