MNL Crypto JS

Introduction

MNL Crypto JS is a hybrid (RSA+AES) encryption and decryption toolkit for JavaScript, including automatic and persistent key management on React Native. MNL Crypto JS combines RSA and AES encryption algorithms making it possible to efficiently encrypt and decrypt large messages. This cross-platform library is based on Forge and designed to work in tandem with python's Cryptography.

Documentation

Getting started

• Introduction
• Documentation
• Installation

Features

• Initialization
• Encryption
• Decryption
• Signatures
• Verifying
• RSA keypairs
• React Native key management

Installation

npm install mnl-crypto-js

Importing

React Native

import {Crypt, keyManager, RSA} from 'mnl-crypto-js';

Features

Initialization

// Basic initialization
var crypt = new Crypt();
var rsa = new RSA();

// Increase amount of entropy
var entropy = "Random string, integer or float";
var crypt = new Crypt({entropy: entropy});
var rsa = new RSA({entropy: entropy});

Encryption

MNL Crypto JS provides basic encryption function which supports also multiple RSA keys, with or without signature. Encrypted message is outputted as a JSON string.

var message = 'Hello world!';

// Encryption with one public RSA key
var encrypted = crypt.encrypt(publicKey, message);

// Function also supports encryption with multiple RSA public keys
var encrypted = crypt.encrypt([publicKey1, publicKey2, publicKey3], message);

// Encryption with signature
var encrypted = crypt.encrypt(publicKey, message, signature);

Pretty-printed sample output

{
    "v": "mnl-crypto-js_0.1.2",        // Current package version
    "iv": "CmtyaZTyzoAp1mTNUTztic0v1...", // Initialization vector
    "keys": {                             // Encrypted AES keys by RSA fingerprints
        "85:3d:10:e1:56...": "bHaTF9...",
        "d3:48:6a:e9:13...": "t9eds3..."
    },
    "cipher": "+iwVFsC2dECBQvwcm9DND..."  // Actual encrypted message
    "signature": "sdL93kfdm12feds3C2..."  // Signature (optional)
}

Decryption

Decrypting message with MNL Crypto JS is as easy as encrypting. Decryption function can decrypt any message which has been encrypted with keypair's public key. Decrypted message is outputted as a JSON object.

var encrypted = '{"v":"mnl-crypto-js_0.1.0","iv":"CmtyaZTyzoAp1mTN...';

// Decrypt encryped message with private RSA key
var decrypted = crypt.decrypt(privateKey, encrypted);

// Get decrypted message
var message = decrypted.message;

Sample output

{
    message: "Hello world!",            // Actual decrypted message
    signature: "sdL93kfdm12feds3C2..."  // Signature (optional)
}

Signatures

MNL Crypto JS provides simple message signing. When issuer signs a message, message receiver can be sure of the message issuer.

var message = 'Hello world!';

// Create a signature with ISSUER's private RSA key
var signature = crypt.signature(issuerPrivateKey, message);

// Encrypt message with RECEIVERS public RSA key and attach the signature
var encrypted = crypt.encrypt(receiverPublicKey, message, signature);

Verifying

Message receiver needs to have message issuer's public RSA key in order to verify message issuer.

// Encrypted message with signature
var encrypted = '{"v":"hybri... ..."signature":"sdL93kfd...';

// Decrypt message with own (RECEIVER) private key
var decrypted = crypt.decrypt(receiverPrivateKey, encrypted);

// Verify message with ISSUER's public key
var verified = crypt.verify(issuerPublicKey, decrypted);

Verification function return true or false depending on whether the verification was successfull.

RSA keypairs

MNL Crypto JS RSA key generation function is based in Forge key pair generation function. As a difference MNL Crypto JS returns keypair in PEM format.

// Initialize RSA-class
var rsa = new RSA();

// Generate RSA key pair, defaults on 4096 bit key
rsa.generateKeypair(function(keypair) {

    // Callback function receives new keypair as a first argument
    var publicKey = keypair.publicKey;
    var privateKey = keypair.privateKey;
});

// Generate 1024 bit RSA key pair
rsa.generateKeypair(function(keypair) {

    // Callback function receives new 1024 bit keypair as an argument
    var publicKey = keypair.publicKey;
    var privateKey = keypair.privateKey;
}, 1024);  // Key size

// RSA can be also initialized with options
var rsa = new RSA({
    keySize: 4096, 
    rsaStandard: 'RSA-OAEP'  // RSA-OAEP or RSAES-PKCS1-V1_5, 
});

React Native key management

Key manager works when using React Native. It automatically generates, saves and fetches device specific keypair from the device's storage.

import {keyManager} from 'mnl-crypto-js';

// Get device specific RSA key pair
keyManager.getKeys(function(keypair) {

    // Callback function receives new keypair as a first argument
    var publicKey = keypair.publicKey;
    var privateKey = keypair.privateKey;
});