node-cryptojs-aes

node-cryptojs-aes is a minimalist port of cryptojs javascript library to node.js, that supports AES symmetric key cryptography.

Unlike node.js native crypto library, node-cryptojs-aes removes openssl dependency.

It is built upon award winning browser side javascript library CryptoJS. currently, it has been updated to be compatible with CryptoJS version 3.0.2.

node-cryptojs-aes doesn't make any modification to original cryptojs library, the syntax remains the same in accordance with CryptoJS documentation.

node-cryptojs-aes doesn't rely on any external library, such as native openssl libary or any external node.js modules. As a node.js module, it can simply be installed through npm package management system. There is no configuration needed also.

node-cryptojs-aes maximises node.js design spirit. Browser side and server side are running identical javascript cryptography codebase. It allows coder to migrate any browser side logic to server or vice versa without any modification. The message passing between server side and client side has been drastically simplified. The encrypted JSON data is passed between client side and server side without any additional parsing or encoding effort made on both side.

Features

• Self Contained It doesn't rely on any external dependency.
• Server Side Cryptography It is the only up and running server side javascript cryptography library so far.
• Cross Platform It is working across all node.js supported platform.
• Code Base Browser and Server share same codebase.
• AES symmetric key cryptography It supports AES-128, AES-192 and AES-256 Encryption.
• Encoding It supports Base64 encoding, Hexadecimal, Utf-8 and binary.
• Cipher Input The key or iv(initialization vector) can be passed in as parameter of encryption function, or single passphrase can be passed in as parameter.

Sample Usage

This is a complete example of server encrypt data, browser request encrypted data and passphrase, and processing decipher subsequently.

The logic on node.js server http request handler consists of two parts.

Right off the bat, it generates random passphrase.

//import crypto module to generate random binary data
var crypto = require('crypto');

// generate random passphrase binary data
var r_pass = crypto.randomBytes(128);

// convert passphrase to base64 format
var r_pass_base64 = r_pass.toString("base64");

console.log(r_pass_base64);

Then, it performs data encryption

//import node-cryptojs-aes modules to encrypt or decrypt data
var node_cryptojs = require('node-cryptojs-aes');

//node-cryptojs-aes main object;
var CryptoJS = node_cryptojs.CryptoJS;

// custom json serialization format
var JsonFormatter = node_cryptojs.JsonFormatter;

// encrypt plain text with passphrase and custom json serialization format, return CipherParams object
var encrypted = CryptoJS.AES.encrypt("I love maccas!", r_pass_base64, { format: JsonFormatter });

// convert CipherParams object to json string for transmission
var encrypted_json_str = encrypted.toString();

console.log(encrypted_json_str);

JsonFormatter is a custom json serialization implementation, you might create your prefered json serialization to fit into your own structure. The code snippets of JsonFormatter shipped with node-cryptojs-aes is as follows.

//create custom json serialization format
var JsonFormatter = {
    stringify: function (cipherParams) {
        // create json object with ciphertext
        var jsonObj = {
            ct: cipherParams.ciphertext.toString(CryptoJS.enc.Base64)
        };
        
        // optionally add iv and salt
        if (cipherParams.iv) {
            jsonObj.iv = cipherParams.iv.toString();
        }
        
        if (cipherParams.salt) {
            jsonObj.s = cipherParams.salt.toString();
        }

        // stringify json object
        return JSON.stringify(jsonObj)
    },

    parse: function (jsonStr) {
        // parse json string
        var jsonObj = JSON.parse(jsonStr);
        
        // extract ciphertext from json object, and create cipher params object
        var cipherParams = CryptoJS.lib.CipherParams.create({
            ciphertext: CryptoJS.enc.Base64.parse(jsonObj.ct)
        });
        
        // optionally extract iv and salt
        if (jsonObj.iv) {
            cipherParams.iv = CryptoJS.enc.Hex.parse(jsonObj.iv);
        }
            
        if (jsonObj.s) {
            cipherParams.salt = CryptoJS.enc.Hex.parse(jsonObj.s);
        }
        
        return cipherParams;
    }
};

If running express to serve http request on node.js, the response can be

app.get('/crypto', function(request, response) {

    // encryption logic here

    response.json({
    encrypted : encrypted_json_str,
    passphrase : r_pass_base64
    });

});

On browser side, it will query the encrypted json string and also passphrase. If using AJAX to access, the code can be

$.get("/crypto", function(data){

    // retrieve encrypted json string 
    var encrypted_json_str = data.encrypted;
            
    console.log("encrypted json string is: " + encrypted_json_str);
            
    // retrieve passphrase string
    var r_pass_base64 = data.passphrase;
            
    console.log("passphrase is: " + r_pass_base64);
            
    // decrypt data with encrypted json string, passphrase string and custom JsonFormatter
    var decrypted = CryptoJS.AES.decrypt(encrypted_json_str, r_pass_base64, { format: JsonFormatter });

    // convert to Utf8 format
    var decrypted_str = CryptoJS.enc.Utf8.stringify(decrypted);
            
    console.log("decrypted string: " + decrypted_str);
});

Also remember to add cryptojs javascript library and JsonFormatter to your index.html file.

<script type="text/javascript" src="http://chengxianga2008.github.com/node-cryptojs-aes/client/aes.js"></script>
<script type="text/javascript" src="http://chengxianga2008.github.com/node-cryptojs-aes/client/jsonformatter.js"></script>

Installation

Install through npm

npm install node-cryptojs-aes

Changelog

node-cryptojs-aes Version 0.3.7 - 01/08/2012

• Add browser side support

node-cryptojs-aes Version 0.3.4 - 21/07/2012

• update to cryptojs v3.0.2

Donation

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