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----- Forwarded message from Bob Margolis <[email protected]> -----
Date: Mon, 25 May 1998 12:54:47 -0500
From: Bob Margolis <[email protected]>
To: [email protected]
Subject: [Spooks] Digital Steganography
Secret Messages: Army Researchers Discover Advance Technique To Relay
Information
Army researchers bring new meaning to the phrase, 'a picture's worth
a thousand words.'
An advanced technique for hiding secret messages inside of images is
a new discovery made recently by U.S.Army Research Laboratory (ARL)
researchers and a Federated Laboratory partner from the University of
Delaware.
"As a method to provide secure communications on the battlefield, we
are pursuing research in the area of digital steganography," says
Lisa Marvel, an electronics engineer at ARL's Information Science &
Technology Directorate.
The Greek word, steganography, means covered writing.
"Our initial system involves embedding hidden messages within images.
Images that are typically transmitted over the battlefield, such as
weather or terrain maps," she says.
The hidden message, be it an authentication mark, time stamp or new
orders to a commander, is completely undetectable and resistant to
removal and arbitrary decoding. Only the intended recipient holding
the 'key' can decode the hidden message.
Consider for a moment the impact of this new capability. U.S. Forces
are pent behind enemy lines and out numbered three to one. The
commander is not able to communicate their situation to base, because
an enemy listener is detected on the communication network.
The commander orders a message be sent through the Stego
Communication System. In less than 45 seconds a soldier types the
message on a laptop computer, hides the message in a map and sends it
to base undetected. U.S. troops are deployed with enemy forces
unaware of the impending ambush. U.S. soldiers are recovered with no
casualties.
Steganography is part of ARL's defensive information warfare efforts
under the Federated Laboratory Program. The research began in
February 1997 and is projected to continue over the next two years.
"The result of this basic research can be packaged as software that
can run on any laptop, anywhere. The main focus for the next two
years is to increase the amount of undetectable information that we
are able to hide in an image and develop techniques that make
messages even more resilient to any kind of corruption," Marvel says.
Typically, basic research is projected for use five years out. But,
Marvel says this particular work is implementable in a shorter
timeframe. She predicts that when the research is completed in two
years it will just be a matter of software rewrite and packaging,
which will take about 6 months before it can actually become a true
product.
Marvel credits the collaborative work, commissioned by the Federated
Laboratory, for the successful progress of the project. Marvel
developed the initial test system, guided by Dr. Charles Boncelet,
Professor of electrical engineering at the University of Delaware.
"Dr. Boncelet brought in some specific insights and his expertise in
random signals and noise truly contributed to the success of the
work," Marvel says.
Dr. Charles Retter another ARL engineer provided his expertise in low
rate error correcting codes, "which is key to how we are able to
extract the message from the image without having the original
image," she adds.
Digital steganography is a new topic of research that incorporates
ideas from communications, cryptography, information theory, and
signal processing. So far, very little information exists in the
formal literature on this topic, unlike digital watermarking which is
currently a very active area of research.
Although similar, steganography differs from watermarking in several
aspects. For example, digital watermarking is used to embed a visible
or invisible signature into a medium in order to indicate ownership,
such as the station insignia seen in the bottom corner of a
television screen during programming.
Steganography, on the other hand, is used to encode a hidden message
typically much larger than a signature, Marvel explains.
In preparing to file for a patent, the ARL researchers are conducting
the required background research on the prior art.
"We found that a few basic techniques used over the years work pretty
well, but are not nearly as sophisticated or complete. It appears
that our technique is unique," Marvel concludes.
---
Submissions [email protected]
----- End forwarded message -----
--
Dave Emery N1PRE, [email protected] DIE Consulting, Weston, Mass.
PGP fingerprint = 2047/4D7B08D1 DE 6E E1 CC 1F 1D 96 E2 5D 27 BD B0 24 88 C3 18