From: Sergey Goldgaber <sergey@delbruck.pharm.sunysb.edu>
Date: Tue, 8 Mar 94 10:58:36 PST
To: Peter Wayner <pcw@access.digex.net>
Subject: Re: more steganography talk
In-Reply-To: <199403051330.AA13596@access2.digex.net>
Message-ID: <Pine.3.89.9403081330.A5604-0100000@delbruck.pharm.sunysb.edu>
MIME-Version: 1.0
Content-Type: text/plain


On Sat, 5 Mar 1994, Peter Wayner wrote:

> Sorry to be so distracted. This is a very interesting topic for
> me, but I've been bogged down with more prosaic topics. I think
> the Mimic FUnction implementation that I did is a very general
> standard for steganography. On the current level, it just deals
> with text, but you can make it do bits by just using the alphabet
> of just plain {0,1}.
> 
> Here are the important points about it:
> 
> 1) If the grammars are made complex enough, they can simulate
> anything you can compute with a computer. I.e. You can encode
> data in a Turing-complete way. 

I find it fascinating how complimentary cryptography and AI are!


> is done by translating RSA encryption into
> a context-free grammar.

I wonder if anyone has actually gone to all the trouble of 
developing some kind of binary CFG?  It should be easier to design 
than an equally effective human-language Turing-complete CFG.


> that there could be many practical "incomplete" attacks
> that worked in general cases. 

What kinds of "incomplete" attacks could possibly work against
Mimic functions implementing Turing-complete CFGs?
 

> 4) It is still unclear how to generate RSA-level strength
> with Mimic Functions. 

Can't you simply use a Turing-complete CFG, and meta-CFG?
Do such things exist on computer media?


> Understanding what makes grammars hard and easy to grok is a 
> hard question. 

Why not just ask an AI?  :)


> 6) The process is slightly difficult to implement, but I've
> got two running versions (as I've mentioned before on the 
> list). One in C and the other in Pascal.

Do you know if anyone has ported either of those over to anything
other than the Mac?



Good to have you join the discussion, BTW...

Sergey