JS RSA Encryption

by Ivo Moor

Index

1. Description
2. Prerequisites
3. Installation
4. Usage

Description

This repository contains a JavaScript library that allows the encryption of files using both the AES and RSA algorithms. The library only provides the functions for encrypting data The decryption of the data is not part of this application (yet), but is possible in iOS via linked project cordova-plugin-rsacertificate.

The encryption steps executed via the JS library includes the following:

• Take a text string
• Generate a random password (16 characters), called the secret key
• Generate another random password (16 characters), called the initialization vector
• Use AES encryption with the secret key and initialization vector to encrypt the text string
• Ask the user for a PEM-file, which is the public key of a RSA certificate (see usage for more details)
• Use RSA encryption with the PEM file to encrypt a concatenation of the secret key and the initialization vector
• Combine the RSA encrypted AES secret key and initialization vector (as key) with the AES encrypted text string (as text) into a JSON file

See the 'Usage' section to find out how the library can be used. Alternatively you can download the contents of folder "demo_app" to run the demo application.

Prerequisites

• jQuery library
  The jQuery library is used to create promisses
  
  
• CryptoJS library
  The AES encryption in JavaScript requires the CryptoJS library which is also included in teh demo_app folder.
  
  
• RSA Key Pair
  In order to encrypt text using the RSA algorithm, a public key is required. Information about generating a RSA key pair is explained in detail in related repo Cordova RSA Certificate.
  
  
• WebCrypto API
  The RSA encryption is done via the browsers WebCrypto API. This is quite new and not supported in older browsers. Please check if your browser supports this API via caniuse.com.

Installation

In order to make use of the JS Library, you will need to:

• copy the files inside folder "demo_app/js/" into your web application
• import the files into your web application via the tag:

    <script src="js/jquery/jquery.min.js"></script>
    <script src="js/crypto-js/Crypto.js"></script>
    <script src="js/crypto-js/AES.js"></script>
    <script src="js/crypto-js/BlockModes.js"></script>
    <script src="js/jbi_encryption.js"></script>

Usage

The JavaScript library has one method that allows you to do the encryption:

  justbi.encryption.rsa.encryptText(plainText, rsaPublicKey).then(
    function (encryptedText) {
      console.log(encryptedText)
    },
    function (err) {
      console.error("Whoooops: " + err)
    }
  );

A demo application that shows how a text string can be encrypted using a RSA public key (PEM) can be downloaded from the "demo_app" folder.