From: uri@watson.ibm.com
Date: Thu, 11 Mar 93 14:18:16 PST
To: J.Michael Diehl <mdiehl@triton.unm.edu>
Subject: Re:  Hidden encrypted messages
In-Reply-To: <9303111501.AA26622@lynx.cs.wisc.edu>
Message-ID: <9303112216.AA15346@buoy.watson.ibm.com>
MIME-Version: 1.0
Content-Type: text/plain


 > So I say, "Damn! CRC Error!  Must be a bad disk.  Well, no point in keeping
 > THIS sitting around."

Yeah, but remember, in the world we're heading to, presumption
of innocence is worth even less, than President's word!
Then it will be *your* responsibility to satisfy the
Inquisitor, or he might not let you out from his
building, where you were invited to explain
yourself and your messages. (:-) (:-(

 > > is how to produce on demand a causal explanation of data (which actually
 > > contains an encrypted message) that satisfies an investigator and
 > > doesn't reveal the encrypted message.  Some simple scheme like, "Uh,
 > > it's the result of my new random number generation algorithm" isn't
 > > likely to be *satisfying* and is certain to produce the response,
 > > "OK, let's see the algorithm."

And the response to this will be: "Sure, here it is, this
nice hardware implementation. You may have it, if you
wish!" (:-)  It's fool-proof, but  still the Big
Brother might dislike your desire to play with
those bad random generators, and decide,
that you better be kept in KZ-camp...

Probably creating a  GIF/TIFF/whatever  file yourself,
with normal consumer-grade equipment (noise-prone :-)
and substituting it's LSB (or whatever certainly lies
BELOW the noise floor) with bits of the message, does
sound like the best choice today.

Advantages:
	1) Doesn't look suspicious, no more, than
	   "traditional" sending photos of your
	   house, family, yourself...

	2) Has enough of bandwidth to communicate
	   reasonably large personal messages
	   (though a binary og PGP might
	   not fit into a "normal"
	   GIF file :-).

	3) Requires only widely available consumer
	   appliances (Camcoder, digitizer, .....).

	4) The image doesn't have to be known to your
	   correspondent in advance (a big one!).

Disadvantages:
	1) Somebody has to do it, to write code, to
	   buy a Camcoder (:-).

	2) May lead to outlawing of ALL the image and
	   sound transmission  via  electronic media,
	   if Big Brother gets really annoyed (:-).

	   [Don't laugh, you! Look at the latest
	    Scanner Bill! :-]

Regards,
Uri.
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