From: Hal Finney <hal@rain.org>
Date: Tue, 20 May 1997 03:08:58 +0800
To: cypherpunks@cyberpass.net
Subject: Re: Information Hiding Workshop
Message-ID: <199705191846.LAA31650@crypt.hfinney.com>
MIME-Version: 1.0
Content-Type: text/plain


> WWW version of cfp at http://www.cl.cam.ac.uk/users/rja14/ihws.html
>
> Details of the first (1996) information hiding workshop are at
> http://www.cl.cam.ac.uk/users/fapp2/steganography/bibliography/workshop.html

The second URL above has abstracts from the conference, many of which sound
very interesting from a CP point of view.  It's kind of strange though that
this topic encompasses both steganography and fingerprinting.  The first
has connotations of freedom, while the second connotes restrictions.  What
both have in common is embedding information undetectably and/or unremovably.

The conference proceedings, "Information Hiding", are currently checked out
from the local university library but I will be looking for them.  There
sounds like a lot of good stuff.  Check out the URL for the T. Aura paper
below; it has some statistics on actual LSB distributions in digital
images, with implications for doing truly undetectable stego.

Below are a few of the abstracts, with URL's for more info where available.

Hal

===

Stretching the Limits of Steganography 

R Anderson, Info Hiding 96 pp 39--48 

The author provides a brief overview of the state of the art in
steganography, and shows how public key steganography is possible ---
at least in the presence of a passive warden. The basic idea is that
if the communicating parties can manipulate at least one out of n bits
in the cover text, then the warden can not distinguish the parity of
successive blocks of n bits from random noise; accordingly these parity
bits can be used to hide cipher text in plain sight. Information theoretic
limits of general steganography are also discussed, and it is shown
that parity techniques can make many systems more efficient. Finally,
the differential effectiveness of active and passive wardens is discussed.

http://www.cl.cam.ac.uk/ftp/users/rja14/stegan.ps.gz 

===

Computer Based Steganography: How It Works and Why Therefore Any
Restrictions on Cryptography Are Nonsense, At Best 

E Franz, A Jerichow, S Möller, A Pfitzmann, I Stierand, Info Hiding 96 pp 7--21 

The authors discuss a system for hiding ciphertext in the low order bits
of an ISDN telephone signal, and report measurements of the perceptibility
of various covert signal levels as a function of the cover signal and
background noise. They also discuss the meaning of perfect and pragmatic
security in the stego context. They argue that steganography is easy,
and thus restrictions on crypto will simply force criminals to use stego
which will make the law enforcement job harder.

===

Practical Invisibility in Digital Communications 

T Aura, Info Hiding 96 pp 265--278 

The author discusses some of the problems of information hiding,
including synchronising with a cover message which is a stream such
digital audio. Where the cover message is a block, such as a digital
picture, his technique is to use the Luby-Rackoff construction to
embed the hidden bits pseudorandomly throughout the picture. A test
implementation using SHA as the underlying primitive is reported.

http://deadlock.hut.fi/ste/ste_html.html
http://www.tcm.hut.fi/Opinnot/Tik-110.501/1995/steganography.html 

===

Establishing Big Brother Using Covert Channels and Other Covert Techniques 

Y Desmedt, Info Hiding 96 pp 65--71 

The author discusses a number of ways in which covert technologies
that are initially deployed for relatively mundane purposes, such as
copyright protection, can end up being subverted to provide the means
of surveillance. This problem could become progressively more serious
as more and more everyday objects become endowed with some kind of
intelligence and communications capability.

===

Anonymous Addresses and Confidentiality of Location 

IW Jackson, Info Hiding 96 pp 115--120 

The author describes how anonymous remailers can be used to process
personal location information from active badges. The goal is that each
user should be able to control who has access to information about his
location; the mechanism is that the remailers forward this information
to a server that the user trusts to enforce his security policy. The
crypto protocols used in this system are described.