crypto-gcm

Encrypt / Decrypt data with AES-256-GCM.

Different encodings for plaintext and payload are supported.

No dependencies! Just a shell around crypto to make it easier to use.

Everything happens synchronously, so no callbacks/promises/async.

Install

npm install crypto-gcm

WeakMap

To store the encryption key, a WeakMap is used.

If you forget to call cg.destroy() and cg goes out of scope, the saved encryption key inside cg would still reference itself, and so will not be set for garbage collection, leading to a memory leak.

Since we are using a WeakMap, each dictionary entry of cg inside the WeakMap does not hold a reference to itself, so in the above situation, there would be no more references to the cg instance, and so the entry would be set for garbage collection, and be removed, preventing a memory leak of the private key if you forget to call cg.destroy().

Usage

'use strict';

const crypto = require('crypto');
const CryptoGcm = require('crypto-gcm');

// create key
const key = crypto.randomBytes(32);

// create instance (you can create multiple instances)
const cg = new CryptoGcm({
    key,
    encoding : {
      plaintext : 'utf8', // also supported: ascii, buffer
      payload : 'base64'  // also supported: base64, hex
    }
})

// ut8 string
const plaintext = 'my plaintext';

// will be base64 string
const payload = cg.encrypt(plaintext);

// check if encryption failed
if (!payload) {
  // encryption failed, invalid plaintext (encoding)
}

// will be utf8 string
const decrypted = cg.decrypt(encrypted);

// check if decryption failed
if (!decrypted) {
  // decryption failed, invalid payload (encoding)
}

// will be true
decrypted === plaintext;

// when you're done with this instance
cg.destroy();

Tests

npm install && npm test

Todo

• [ ] deal with large plaintext inputs, which will consist of chunks
• [ ] add Base64 as a valid plaintext encoding
• [ ] ~~make sure decrypted payload is correct type (= plainext encoding)~~

Compatibility

tested on node v6.2.2

License

MIT