From: monty.harder@famend.com (MONTY HARDER)
Date: Wed, 19 Jul 95 20:37:06 PDT
To: CYPHERPUNKS@toad.com
Subject: Re: Stego Standards Silly
Message-ID: <8AD8535.00030001EC.uuout@famend.com>
MIME-Version: 1.0
Content-Type: text/plain


LM> I think I need to clarify my threat model. I'm positing a scenario in which
LM> transmission of ciphertext and stegoed anything is illegal, but transmission
LM> and use of "conspicuous" digital signatures is legal. Furthermore, the govt.
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  Ah.  No big deal then.  After stegoing, you sign the GIF.

LM> sanitizes the LSBs of digital images for our protection, perhaps distorting
LM> a mean of X% of the LSBs of a mean of Y% of transmitted images. Out-of-stego-
LM> channel checksummation would IMHO be crucial in such a situation.

  Sending multiple copies of the same GIF would go a long way toward
solving this, if X% and Y% were low enough. Say I get 5 copies, and
reconstruct the origial via a "voting" protocol. Also, if we break down
the file into smaller blocks, and sign each block individually, we can
narrow down the errors.

  But I am having a real problem with an overt policy of fiddling with
people's mail. If they did that, it would likely cause a huge backlash
that would be felt at the ballot box.



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