Encrypt and Decrypt aes-256-ctr algorithm using crypto library in node.js

crypto.js

const crypto = require('crypto'),
    algorithm = 'aes-256-ctr',
    password = 'd6F3Efeq';
    
 function encrypt(chunk) {

	var cipher,
	    result,
	    iv;

	// Create an iv
	iv = crypto.randomBytes(16);

	// Create a new cipher
	cipher = crypto.createCipheriv(algorithm, password, iv);

	// Create the new chunk
	result = Buffer.concat([iv, cipher.update(chunk), cipher.final()]);

	return result;
}

function decrypt(chunk) {

	var decipher,
	    result,
	    iv;

	// Get the iv: the first 16 bytes
	iv = chunk.slice(0, 16);

	// Get the rest
	chunk = chunk.slice(16);

	// Create a decipher
	decipher = crypto.createDecipheriv(algorithm, password, iv);

	// Actually decrypt it
	result = Buffer.concat([decipher.update(chunk), decipher.final()]);

	return result;
}