xxtea-stream

A node/browserify streaming xxtea encryption and decryption module

I wanted to get my hands dirty with a simple encryption that would stream and work both node and browser side. This is the result.

Ported from http://www.movable-type.co.uk/scripts/tea-block.html

Pros

• Encrypted file size can be exactly the same as the original size
• streaming allows for low memory footprint
• decent speed
• runs in pure node or on browser with browserify

Cons

This should be considered a weak crypto. From Wikipedia:

XXTEA is vulnerable to a chosen-plaintext attack requiring 259 queries and negligible work.[1]

Install

npm install xxtea-stream

Usage

var xxtea = require('xxtea');
var pipe = new xxtea.Encrypt('8339d93jdooe2dwd')
var pipe = new xxtea.Decrypt('8339d93jdooe2dwd')

When creating an instance, you must tpass in a string of exactly 16 characters (bytes) as the key. The key is symetric in that the same must be passed in the Encrypt and Decrypt function.

Encryption

var xxtea = require('xxtea');

fs.createReadStream(".secret.txt")
  .pipe(new xxtea.Encrypt('8339d93jdooe2dwd')))
  .pipe(fs.createWriteStream('out.text.tea'))
  .on('close', decrypt);

Decryption

var xxtea = require('xxtea');
var bops = require('bops')

fs.createReadStream("./out.text.tea")
  .pipe(new xxtea.Decrypt(8339d93jdooe2dwd'))
  .pipe(concat(function(contents) {
    contents.toString('utf-8'); // shhh - dont tell!
  }))

In Browser

var drop = require('drag-and-drop-files');
var createReadStream = require('filereader-stream');
var xxtea = require('xxtea-stream');


drop(document.body, function(files) {
  var first = files[0]
  createReadStream(first)
    .pipe(new xxtea.Decrypt("secret12secret12"))
    .pipe(concat(function(contents) {
        console.log(contents.toString('utf-8')); // shhh - dont tell!
    }))
})

Decrypt an audio file and play it

var oReq = new XMLHttpRequest();
oReq.open("GET", "younger.mp3.tea", true);
oReq.responseType = "blob";

oReq.onload = function (oEvent) {

  createReadStream(oReq.response)
     .pipe(new tea.Decrypt(bops.from("secret12secret12")))
     .pipe(concat(function(contents) {
     var objectURL = window.URL.createObjectURL(new Blob([contents], {type: 'audio/mpeg'} ));
     new Audio(objectURL).play();
  }))
};
oReq.send(null);