README

Bury

A cryptographic and steganographic image library for nodejs.

========================

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     88      ,8P     88        88      88      `8i      Y8b,___,d888
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A nodejs port of BuriedUnderTheNoiseFloor.

Write up is at my blog.

If anyone is feeling generous, my bitcoin address is 17da1aqXEhdqMkbEq66nc2n5DeAnrnNbsK. Donations help me justify spending time on my computer to my wife. :-)

Comments and issues posted on github will be answered. Pull-requests are always welcome if you've fixed or enhanced something.

Installation

git clone https://github.com/jspark311/node-bury.git
cd node-bury
npm install bury

Usage

Encrypting

var Bury = require('bury');

var options = {
  enableRed:      true,
  enableGreen:    true,
  enableBlue:     true,
  visibleResult:  false,
  rescaleCarrier: true
};

var test_image = new Bury('./test_carrier.jpg', 'saddroPs', options);

var msg = 'This is a silly test message that the NSA will spend millions of dollars to unearth.'
test_image.setMessage(msg);
test_image.outputImage('./test_carrier.png');

Decrypting

var Bury = require('bury');

var test_readback = new Bury('./test_carrier.png', 'saddroPs');
console.log(test_readback.getMessage());

Testing passwords for mutual compatibility

var Bury = require('bury');

// testPasswordCompatibility() returns 'true' if the provided passwords are mutually compatible.
//   'false' otherwise. The function requires at least two passwords. Maximum of three, because we
//   can only have (at maximum) three independent channels.

console.log('Are these passwords compatible? ' + 
  Bury.testPasswordCompatibility('key_for_steg-img.php', 'key_for_form.php'));

console.log('Are these passwords compatible? ' + 
  Bury.testPasswordCompatibility('one-of-thess-passwords', 'is-not-mutally', 'compatible'));

Compatibility note

The carriers produced by this code will not inter-operate with those produced with the PHP version, and vice-versa. The only reason for this is that the default PRNG in PHP was able to be seeded, and the one in node is not. This might not be a problem, as I at least had enough foresight to bake a version field into the header in the original. So I have incremented this value for the JS code.

This problem may be resolvable by changing the PHP code to use the same mersenne twister algorithm used here. But I doubt that this is going to cause anyone enough grief to care.

Just sayin'...

TODO

Compression is broken at the moment.
File-embedding is untested.
The control-flow that this code inherited from the PHP original feels awful in JS. There are too many synchronous operations and arbitrary branching. Need to impart a more functional style to it.
There is presently no enforcement of "one instance, one operation". Risks obtuse crypto bugs caused by crufty IVs and seeded RNGs from prior operations.
It would be nice to be able to automatically write output files if such-and-such an option parameter is passed in at instantiation. The same goes for encrypting.
Decrypting can (in principle) be done automatically. With nothing more than the carrier and a password, a header can be discovered and the data retrieved. But, at present, you must make a separate function call.
Write unit tests. Should be easy to do, since the criteria for success is unambiguous.

License is MIT, so be free.

---J. Ian Lindsay

Usage no npm install needed!