Node.js Crypto Module Examples

cryptdemo.js

/**
 * Joey Whelan
 * 3 examples on usage of the node crypto module
 */

var crypto = require('crypto');
var plainText = '1234567812345678';

try
{
//Method 1 - Specify encoding on the cipher and do a string concat on the ciphertext. This works.
	var cipher1 = crypto.createCipher('aes256', 'password');
	var cipherText1 = cipher1.update(plainText, 'ascii','binary');
	cipherText1 += cipher1.final('binary');
	console.log('Method 1 - plainText:' + plainText );
	console.log('Method 1 - cipherText length:' + cipherText1.length);
	var decipher1 = crypto.createDecipher('aes256', 'password');
	var result1 = decipher1.update(cipherText1);
	result1 += decipher1.final();
	console.log('Method 1 - result:' + result1);
	
//Method 2 - Use a Buffer object for the cipher text concatenation.  This works.
	var cipher2 = crypto.createCipher('aes256', 'password');
	var cipherText2 = Buffer.concat([cipher2.update(new Buffer(plainText)), cipher2.final()]);
	console.log('Method 2 - plainText:' + plainText );
	console.log('Method 2 - cipherText length:' + cipherText2.length);
	var decipher2 = crypto.createDecipher('aes256', 'password');
	var result2 = decipher2.update(cipherText2);
	result2 += decipher2.final();
	console.log('Method 2 - result:' + result2);
	
//Method 3 - Don't specify any encoding on the cipher and do a string concat. This won't work.
	var cipher3 = crypto.createCipher('aes256', 'password');
	var cipherText3 = cipher3.update(plainText);
	cipherText3 += cipher3.final();
	console.log('Method 3 - plainText:' + plainText );
	console.log('Method 3 - cipherText length:' + cipherText3.length);
	var decipher3 = crypto.createDecipher('aes256', 'password');
	var result3 = decipher3.update(cipherText3);
	result3 += decipher3.final(); //Boom
	console.log('Method 3 - result:' + result3);
}
catch (err)
{
	console.log(err.message);
}