This is a simple implementation for verify DocuSign Connect API with HMAC validation.

docuSignAuthenticate.js

const verifyWebhook = async event => {
  const keys = [];
  keys.push(event.headers['X-DocuSign-Signature-1']);
  keys.push(event.headers['X-DocuSign-Signature-2']);

  const crypto = require('crypto');
  const hmac = crypto.createHmac('sha256', DOCUSIGN_SECRET_KEY);
  hmac.write(event.body);
  hmac.end();
  const computedKey = hmac.read().toString('base64');
  if (!keys.includes(computedKey)) {
    console.log('webhook signature is not valid.');
    throw new Error('webhook authentication failed.');
  }
};