crypto.createHash()

crypto.createHash(algorithm)

Creates and returns a Hash object that can be used to generate hash digests using the given algorithm.

The algorithm is dependent on the available algorithms supported by the version of OpenSSL on the platform. Examples are 'sha256', 'sha512', etc. On recent releases of OpenSSL, openssl list-message-digest-algorithms will display the available digest algorithms.

Example: generating the sha256 sum of a file

const filename = process.argv[2];
const crypto = require('crypto');
const fs = require('fs');

const hash = crypto.createHash('sha256');

const input = fs.createReadStream(filename);
input.on('readable', () => {
  var data = input.read();
  if (data)
    hash.update(data);
  else {
    console.log(`${hash.digest('hex')} ${filename}`);
  }
});