[6532] in cryptography@c2.net mail archive
Re: The problem with Steganography
daemon@ATHENA.MIT.EDU (William Allen Simpson)
Fri Jan 28 15:42:58 2000
Message-ID: <3890F684.7174CA76@greendragon.com>
Date: Thu, 27 Jan 2000 20:53:58 -0500
From: William Allen Simpson <wsimpson@greendragon.com>
MIME-Version: 1.0
To: Marc Horowitz <marc@mit.edu>
Cc: Rick Smith <rick_smith@securecomputing.com>, cryptography@c2.net
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Catching up on the thread, the comments about fitting the stego into the
image reminded me of http://www.outguess.org/ by Niels Provos. Looks like
he's a few months ahead of you....
Marc Horowitz wrote:
>
> Rick Smith <rick_smith@securecomputing.com> writes:
>
> >> Thus, a 'good' stego system must use a crypto
> >> strategy whose statistical properties mimic the noise properties of the
> >> carrying document. ... So, can't we detect the presence of stego'ed data by
> >> looking for 'noise' in the document that's *too* random?
> >>
> >> ... Once we replace those bits
> >> with data, the bits will have serously random statistical properties. So,
> >> we can detect stego'ed data if the implementation uses any well known
> >> strong encryption algorithm.
>
> If the picture was taken by an actual camera, the least significant
> bits will be random due to the nature of the way CCDs work in the real
> world. They might be biased, but it's not very hard to bias a
> "random" data stream.
WSimpson@UMich.edu
Key fingerprint = 17 40 5E 67 15 6F 31 26 DD 0D B9 9B 6A 15 2C 32
