It's cool but basically solves a problem that no longer exists. Once you've caused enough suspicion, they can simply dig up the records of all the data you've sent, both chaff and wheat, and serve you with an order to disclose your authentication key/lawfully hack you computer and obtain it without asking/apply some lead pipe cryptanalysis and get it anyway. In the end, it's no better than regular encryption, at the cost of being at least twice more inefficient.<p>Still, for all the crypto export nonsense, 1998 appears to have been a more innocent time:<p>> "But access to authentication keys is one thing that
government has long agreed that they don't want to have."
See also "Chaffinch: Confidentiality in the Face of Legal Threats" by Richard Clayton and George Danezis from University of Cambridge, which has some more plausible deniability.<p>(<a href="http://www.cl.cam.ac.uk/~rnc1/Chaffinch.html" rel="nofollow">http://www.cl.cam.ac.uk/~rnc1/Chaffinch.html</a>)
I've thought about writing a Chrome plugin to do something similar. While on it would randomly chaff the low order bits of any image you upload, and would automatically add a chaff postscript to every Gmail. An adversary would have no clue which images/messages contain ciphertext, and which contain nothing but random chaff.
Was unreachable for me, here's the cached version: <a href="http://webcache.googleusercontent.com/search?q=cache:zgl1Lf25QRIJ:people.csail.mit.edu/rivest/Chaffing.txt" rel="nofollow">http://webcache.googleusercontent.com/search?q=cache:zgl1Lf2...</a>
I'm probably misunderstanding this. The way I'm envisioning this is basically a half-dozen parallel conversations, with only one of them being the actual conversation.<p>Couldn't it be easily defeated with contextual analysis? I mean, if it were English sentences, the attacker could just choose a set of packets that make grammatical sense. Or in more real-world examples, you'd just choose the packets that form a valid HTTP session.<p>To work around this, you'd have to choose your chaff packets to flow seamlessly from one to the other, which would make chaffing a really hard problem.