tobyurff

const crypto = require('crypto');

const hmac = crypto.createHmac('SHA256', 'my-webhook-secret');
hmac.update('{ ... }'); // request body
const correctHash = hmac.digest().toString('hex');

const receivedHash = '...'; // e.g. req.get('x-impala-signature');

/*
 * It's important to perform a constant time equality comparison of the