README

node-crypto-gcm

Introduction

A node crypto wrap for AES GCM (Galois/Counter Mode), to make it easy to use AES GCM mode.

The default crypto algorithm is aes-128-gcm. PBKDF2 digest algorithm is sha512, PBKDF2 rounds is 10000.

The output text is URL safe base64 encoding, so it can be safely used in URL without URL encoding.

Install

npm install node-crypto-gcm

Usage

const GCM = require('node-crypto-gcm').GCM;

let plainText = 'To be or not to be, that is the question.';
let gcm = new GCM('password');

let output = gcm.encrypt(plainText);

let decryptedText = gcm.decrypt(output);    // decryptedText should equals plainText

The crypto algorithm can be customized in constructor.

let gcm = new GCM('t86GvATWQV6S', {algorithm: 'aes-256-gcm',
                                   saltLenght: 123,
                                   pbkdf2Rounds: 1000,
                                   pbkdf2Digest: 'sha512'});

Checkout test/gcm_test.js for example usages.

API

class GCM {

    /**
     * @param password {string} password string, will use PBKDF2 to drive encryption key.
     * @param options  {object} optional algorithm parameters.
     *          specific this parameter to custom your own encryption algorithm.
     *          {algorithm: <string. Encrypto algorithm, can be aes-1228-gcm, aes-192-gcm or aes-256-gcm>,
     *           saltLength: <integer. key salt length, default 64.>
     *           pbkdf2Rounds: <integer. PBKDF2 rounds, default 10000. Use large value to slow pbkdf2>,
     *           pbkdf2Digest: <string. PBKDF2 digest algorithm, default is sha512>
     */
    constructor(password, options)

    /**
     * Encrypt plainText.
     *
     * The output raw buffer format:
     *
     *   <salt(12bytes)> <iv(64bytes)> <authTag(16bytes)> <encryptedData>
     *
     * it will be url safe base64 encoded as function return value.
     *
     * @param plainText  utf-8 encoded plain text.
     * @returns {string} url safe base64 encoded encrypted text.
     */
    encrypt(plainText)

    /**
     * decrypt encyptedData.
     *
     * @param encryptedData {string} encrypted data, url safe base64 encoded.
     * @returns {*} decrypted data, utf-8 encoded. or null if decrypt failed.
     */
    decrypt(encryptedData)
}

License

MIT

References

nodejs crypto API

Usage no npm install needed!