var fs = require('fs'),
    crypto = require('crypto');

var key = '14189dc35ae35e75ff31d7502e245cd9bc7803838fbfd5c773cdcd79b8a28bbd',
    cipher = crypto.createCipher('aes-256-cbc', key);
    input = fs.createReadStream('test.txt'),
    output = fs.createWriteStream('test.txt.enc');

input.pipe(cipher).pipe(output);

output.on('finish', function() {
  console.log('Encrypted file written to disk!');
});