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Plausible Deniability From Rockstar Cryptographers
J. Karl Rove writes "Nikita Borisov and Ian Goldberg
(of many, many other projects) have released
Off the Record Messaging
for
Gaim.
Encrypt an IM, prove (at the
time) that it came from you, and deny it later. The
authentication works only when the message is sent; anybody
can forge all the messages he wants afterwards (toolkit included).
Captured or archived messages prove nothing. And forward
secrecy means Big Brother can't read your messages even if
he wiretaps you AND grabs your computer later on. All the gooey goodness
of crypto, with none of the consequences!
They have a
protocol
spec, source
code, and Debian
and Fedora
binaries."
Who needs any of this? Just try what I do: write your messages as GW Basic programs. This is so uncrackable that even I can't tell what is in it after I use it.
This thing sounds great, but before it is really useful it needs to be out there in sufficient numbers. I hope that distros will start installing it by default on their default gaim version.
Treehugger? Treehugger... Treehugger!
How much later is "later"?
"Did I just say that I'd walk the dog?"
"Yes!"
"Nobody can prove that I just said that."
Sometimes Big Brother can 'prove' anything by force. Why do you think he's called Big? Small people need stuff like evidence, proof, and proper legal process. There are many recent examples of Big Brother having his way, proof and fact be damned.
If you create a message, chances are that fragments of the plain text will be in various caches and VM pages on your harddisk. It may not last for very long -- being overwritten by subsequent paging -- but if someone takes your computer soon after, they may find incriminating junk on the HD.
Two wrongs don't make a right, but three lefts do.
It authenticates and creates a "conversation". This allows you to be certain the person on the other end is who you think it is. DH key exchange is performed.
Then, messages sent during that conversation are encrypted using disposable session keys. (128-bit AES w/SHA-1 HMAC).
Think of it as an authentication tunnel down which you send encrypted messages. The message encryption is in no way related to the authentication, and the disposable session keys mean they have no re-use value.
-Charles
Learning HOW to think is more important than learning WHAT to think.
I really want a cryptosystem where I can enter, say, two different plaintexts (of similar length, I imagine) and then there are two keys: the private key, and the decoy key.
If required to give up "your private key" then give up the decoy key. The decoy plaintexts decrypts, and you're done. The real plaintext is still hidden away.
Does anything like this exist?
Wonderful stuff if it does everything it is supposed to do. I can't wait to check it out.
I've often wondered about this when it comes to forensics testimony. For example, even if you have my computer with some incriminating evidence on there, how can you prove beyond reasonable doubt that I put it there? I would think that unless you have a video tape of me typing the incriminating evidence on the keyboard, and can prove that the tape was made at the time in question and is unaltered, is the only way to prove anything.
Computers can be programmed to do anything at anytime, including carrying on a "conversation". You can also easily create an incriminating e-mail message that looks like it was sent, but it never was. Ditto log files, etc. For example, Apache log files are text: it would be trivial to create a script that spoofed a log file with your IP address as the incriminating info...but then how does the plaintiff prove that isn't how it was created?
Let me get this straight - it can be proved that you
a) created a plausible deniability capable link; and
b) intentionally released the key to said link so that someone else could impersonate you later.
Frequently all that's needed is the fact that you communicated with somebody for evidence - not the specifics of what you said. Sure maybe you just called them up and did some heavy breathing down the line - there's no proof you actually _spoke_, but any jury in the world would convict you.
Of course you work around that by creating a new link every hour to the same person, and maybe or maybe not using it - but it still shows you're in communication with them. There's no way around that.
Nice idea, but don't think your child pornography dealing down this link is going to somehow get you off the hook.
Comment removed based on user account deletion
Quick, someone, anyone. Combine this with yesterday's P2P In 15 Lines of Perl: http://developers.slashdot.org/article.pl?sid=04/1 2/15/1953227&tid=95&tid=156&tid=1
Everybody's a libertarian 'till their neighbour's becomes a crack house.
Thus, I can create a key that I send to my friend. He and I discuss things, both using that key for encryption. When we've finished, we publish the key used for the conversation, and anyone can now add to the conversation. Thus, while we keep the key secret between us, we're assured of a private conversation; when we publish the key, anyone can add to it, thus giving the denability
I appear to have a blog. Odd.