Node encryption and decryption https://github.com/chris-rock/node-crypto-examples

crypto-buffer.js

var crypto = require('crypto'),
    algorithm = 'aes-256-ctr',
    password = 'd6F3Efeq';
 
function encrypt(buffer){
  var cipher = crypto.createCipher(algorithm,password)
  var crypted = Buffer.concat([cipher.update(buffer),cipher.final()]);
  return crypted;
}
 
function decrypt(buffer){
  var decipher = crypto.createDecipher(algorithm,password)
  var dec = Buffer.concat([decipher.update(buffer) , decipher.final()]);
  return dec;
}
 
var hw = encrypt(new Buffer("hello world", "utf8"))
// outputs hello world
console.log(decrypt(hw).toString('utf8'));

crypto-ctr.js

// Nodejs encryption with CTR
var crypto = require('crypto'),
    algorithm = 'aes-256-ctr',
    password = 'd6F3Efeq';
 
function encrypt(text){
  var cipher = crypto.createCipher(algorithm,password)
  var crypted = cipher.update(text,'utf8','hex')
  crypted += cipher.final('hex');
  return crypted;
}
 
function decrypt(text){
  var decipher = crypto.createDecipher(algorithm,password)
  var dec = decipher.update(text,'hex','utf8')
  dec += decipher.final('utf8');
  return dec;
}
 
var hw = encrypt("hello world")
// outputs hello world
console.log(decrypt(hw));

crypto-stream.js

// Nodejs encryption of buffers
var crypto = require('crypto'),
    algorithm = 'aes-256-ctr',
    password = 'd6F3Efeq';
 
var fs = require('fs');
var zlib = require('zlib');
 
// input file
var r = fs.createReadStream('file.txt');
// zip content
var zip = zlib.createGzip();
// encrypt content
var encrypt = crypto.createCipher(algorithm, password);
// decrypt content
var decrypt = crypto.createDecipher(algorithm, password)
// unzip content
var unzip = zlib.createGunzip();
// write file
var w = fs.createWriteStream('file.out.txt');
 
// start pipe
r.pipe(zip).pipe(encrypt).pipe(decrypt).pipe(unzip).pipe(w);