Clustered bruteforce password-cracking example

bruteforce.js

const cluster = require('cluster');
const numCPUs = require('os').cpus().length - 1;
const {promisify} = require('util');
const pbkdf2 = promisify(require('crypto').pbkdf2);

if (cluster.isMaster) {
  const workers = [];
  console.log(`Starting ${numCPUs} workers…`)
  for (let i = 0; i < numCPUs; i += 1) {
    workers.push(cluster.fork());
  }

  (async function bruteforce() {
    const theSecret = (await pbkdf2('500', 'salt', 1e5, 32, 'sha512')).toString('hex');

    let sample = 0;
    console.time('bruteforce');
    workers.forEach(worker => {
      worker.send(sample++);

      worker.on('message', ({secret, hash}) => {
        if (theSecret != hash) return worker.send(sample++);

        console.timeEnd('bruteforce');
        console.log(`Your secret is ${secret}`);
        workers.forEach(worker => worker.kill());
      });
    });
  })();
  return;
}

// Worker Code
process.on('message', (sample) => {
  (async () => {
    console.log(`computing "${sample}"…`);
    const hash = (await pbkdf2(String(sample), 'salt', 1e5, 32, 'sha512')).toString('hex');
    if (process.connected) process.send({secret: sample, hash});
  })();
});