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In
<3(_dot_)0(_dot_)3(_dot_)32(_dot_)19971204021239(_dot_)006ea164(_at_)schloss(_dot_)li>,
on 12/04/97
at 03:12 AM, Black Unicorn <unicorn(_at_)schloss(_dot_)li> said:
At 11:20 PM 12/3/97 -0800, you wrote:
If
you are worried about being tortured, the best defense is for Big Brother
to be unable to verify the existence of a PGP message at all. Some stego
programs already kludge this by removing various message headers, but I
don't have references to the techniques handy. I would like to see some
kind of "stealth message" format defined, where the first N bits of the
message (N corresponding to the length of the asymmetric key you are using
to speculatively decrypt) contain the session key, signature keyid, message
length, symmetric algorithm ID, hash algorithm ID, random padding, and
other such details so that if you stego a .WAV file, the only way to tell
is to collect the first 2048 sample LSBits and try decrypting them with
your private key(s) to see if a message header shows up. Otherwise, all
you see is random-looking data that may or may not be a PGP message.
Even more substantial kudos.
I believe that there is a program PGP Stealth that works well for striping
this information from PGP messages before Stego is applied.
We had a rather lengthy discussion on Stego techniques on #pgp the other
day. I have primarily playing with the bit hiding and haven't looked too
much at the PGP header striping. I imagine that if a PGP implementation
could not handle a "striped" PGP message that the Stego preprocessor could
"fix" the encrypted message before passing it to PGP.
- --
- ---------------------------------------------------------------
William H. Geiger III http://users.invweb.net/~whgiii
Geiger Consulting Cooking With Warp 4.0
Author of E-Secure - PGP Front End for MR/2 Ice
PGP & MR/2 the only way for secure e-mail.
OS/2 PGP 2.6.3a at: http://users.invweb.net/~whgiii/pgpmr2.html
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