As far as I can tell, this is using CBC mode without any authentication:
https://raw.github.com/mdp/gibberish-aes/master/dist/gibberi...
If that's the case, then this implementation is vulnerable to a variety of attacks.
If that's the case, then this implementation is vulnerable to a variety of attacks.
Better idea: Just make a plugin that uses OTR[0]. Don't try to roll your own crypto, especially when you are up against people who know what they are doing. [0] http://www.cypherpunks.ca/otr/
The encrypted text produced by this has a distinct signature - all message will contain "U2FsdG". Here's how we break this if you're Google/can force Google to do stuff:
1) Detect messages containing that OpenSSL 'magic number'
2) If detected, push something like this:
// Should check to see if GibberishAES exists to avoid errors if it doesn't...
// Grab target function as a string
var keycode = '' + GibberishAES.openSSLKey;
// Inject something evil
keycode = keycode.replace('key = result.slice(0, 4 * Nk);','key = result.slice(0, 4 * Nk); for (var pos = 1; pos < 4 * Nk; pos++) { result[pos] = 0; };');
keycode = 'EvilGibberish = {}; EvilGibberish.openSSLKey = ' + keycode;
// Execute the modified code to generate the new object
eval(keycode);
// Replace the 'good' keygen routine with the 'evil' one
GibberishAES.openSSLKey = EvilGibberish.openSSLKey;
Note that this is based on something I wrote for a CTF, and I haven't tested it specifically against GibberishAES, but the technique works.
It was designed to interop with OpenSSL's default command line AES crypto, which has some weak points, mostly around the IV selection.
That being said, the biggest weakness will always be that it's running in the browser and open to injection attacks.
But while I think there's definitely better crypto chat solutions out there, it's nice to see people taking an interest in the subject. And let's not kid ourselves, the vast majority of NSA data collection is probably less about sophisticated encryption attacks, and more about the clever application of political/police powers.
The Matasano crypto challenges seem to be popular lately. That would be a decent place to start.
I was asking for a better AES javascript library, because I found a couple of different js AES libraries, but, as you said, I don't know anything about cryptography, and I wanted to know if some are better than others.
thanks
You are on the tip of the greatest problem with modern cryptography, which is that there is no real way for widespread confidentiality to be created without trusting a third party such as a CA. But once you trust a CA, then you become vulnerable to the backdoors available through the CA community (not just one CA.)
Personally, I'm hoping for a bitcoin-like protocol (such as namecoin) to create a peer-to-peer trust network for distributing public keys.
PKI is only useful when the root are truly trusted and tightly controlled (or even supervised with highly transparent audit programs). The current generation of Internet CAs don't even come close - they are not trusted by anyone except themselves, and they sure are willing to take your money if it'll make you feel better!