Researchers Combat Terrorists by Rooting Out Hidden Messages

[R.A. Hettinga]

<http://www.newswise.com/p/articles/view/509563/>

Newswise

Source: University of Delaware 
  
Released: Tue 01-Feb-2005, 13:10 ET 

Researchers Combat Terrorists by Rooting Out Hidden Messages

Libraries
Science News
 
Keywords
STEGANOGRAPHY, STEGANALYSIS, HIDDEN MESSAGES, DIGITAL IMAGES, CRYPTOGRAPHY,
TERRORISM

 Contact Information
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Description
Researchers at the University of Delaware are working to combat terrorism
by developing techniques to detect the use of steganography, which
encompasses various methods of hiding messages in apparently ordinary
digital images and videos.



 Newswise - A University of Delaware research team has received National
Science Foundation funding to combat terrorism by developing techniques to
detect the use of steganography, which encompasses various methods of
hiding messages in apparently ordinary digital images and videos.

It is feared electronic steganography can be used by terrorist
organizations to pass along orders or other vital information
surreptitiously through images posted on the Internet or sent via e-mail.

The grant for more than $167,000 was awarded to Charles Boncelet, UD
professor of electrical and computer engineering, to conduct research in
the relatively new field of steganalysis. Boncelet will work on the project
with Lisa Marvel, a UD graduate now employed by the U.S. Army Research
Laboratory, and with several graduate students.

 Boncelet said steganography is Greek for covered writing, and is a means
by which a person can hide the very fact that they are communicating. In
that, it differs from the better-known practice of cryptography, Greek for
secret writing, in which a message is purposely garbled and can be
understood only by those who have the key to decipher it.

 The two forms of communication are not mutually exclusive, Boncelet said,
and can be combined. A person can encrypt a message and then hide the fact
that they are sending it.

Boncelet previously worked in steganography for the U.S. Army and through
this project will begin working in steganalysis, or the development of
methods by which to seek out steganography.

"The work we are doing is in multimedia, with a focus on digital images,"
Boncelet said. "You can take an image on your web site and use
steganographic techniques to hide a message in the image. The image looks
completely ordinary but if you know the key, you can extract the secret
message."

"The object of the research," Boncelet said, "is to try to figure out how
to find steganography in the images."

The problem is that steganalysis is very difficult because the messages are
hidden by design. However, Boncelet said, "when you hide a message in a
digital image, you change the image a little bit. If you change the image
too much, it gives it away."

The way to determine any changes to an image, given that the steganalyst
does not have the benefit of the original for purposes of comparison, is to
use algorithms and very fast computers to look for unusual features in the
image.

Boncelet said he believes the research will lead to a novel class of
electronic steganography searchers based on image representations that
depend on a quality factor, with the long-term goal being automated
scanners that can rapidly find likely candidates amongst large numbers of
images and videos.

 "Assuming the technique we develop is successful, we hope to branch out to
video and audio," Boncelet said, "but right now the focus is on digital
images."

In addition to the research, the project will provide training in
steganalysis and intelligence techniques to the students involved.

Boncelet said steganography "is a very big fear for governments," adding
that the security agencies that deal with the technique "worry about
terrorists passing messages, or traitors leaking out information from
secure sites."

After the terrorist attacks of Sept. 11, 2001, there was widespread
speculation in the public press that terrorists had used steganography on
the Internet to communicate plans. Although those reports were never
confirmed, the possibility remains a grave concern.

One of the earliest examples of steganography comes from ancient history,
Boncelet said, explaining that a Greek city was surrounded by enemy
soldiers and the leader wanted to get a message to his allies to send
troops. He selected a slave and shaved his head, tattooing the plea for
help on his scalp, then allowed the slave's hair to grow back over the
message. The slave was sent out of the city walls, was captured and
released by the enemy troops, and arrived safely with the message.

In World War II, Boncelet said, American soldiers used steganography to
provide information on their whereabouts to relatives back home by putting
a pinprick on a map. Army censors were forced to pepper letters with
hundreds of pinpricks to offset the practice. German spies used
steganography in microdots, tiny images of typed pages that could be pasted
over periods in seemingly harmless letters.

The NSF grant is for one year and was awarded through the Approaches to
Combat Terrorism Program in the Directorate for Mathematical and Physical
Sciences, which supports new concepts in basic research and work force
development with the potential to contribute to national security.


-- 
-----------------
R. A. Hettinga <mailto: rah at ibuc.com>
The Internet Bearer Underwriting Corporation <http://www.ibuc.com/>
44 Farquhar Street, Boston, MA 02131 USA
"... however it may deserve respect for its usefulness and antiquity,
[predicting the end of the world] has not been found agreeable to
experience." -- Edward Gibbon, 'Decline and Fall of the Roman Empire'

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