subject: Messages of fear in hi-tech invisible ink posted: Thu, 11 Aug 2005 11:42:37 +0100
[whatever you do - stay away from Tappahannock, VA!!! ... LOL.. ]
Messages of fear in hi-tech invisible ink
In 2003 the CIA falsely believed al-Qaida was sending signals to
terror cells through TV. Ian Sample on a scare story
Thursday August 11, 2005
The Guardian
The first sign that something was amiss came a few days before
Christmas Eve 2003. The US department of homeland security raised the
national terror alert level to "high risk". The move triggered a
ripple of concern throughout the airline industry and nearly 30
flights were grounded, including long hauls between Paris and Los
Angeles and subsequently London and Washington.
But in recent weeks, US officials have made a startling admission:
the key intelligence that prompted the security alert was seriously
flawed. CIA analysts believed they had detected hidden terrorist
messages in al-Jazeera television broadcasts that identified flights
and buildings as targets. In fact, what they had seen were the
equivalent of faces in clouds - random patterns all too easily over-
interpreted.
At the heart of the fiasco lies a technique called steganography, the
art, and now hardcore science, of hiding messages. There's nothing
new about steganography, in principle at least. Herodotus tells the
tale of Histiaeus who, in the sixth century BC, shaved the head of
his most trusted slave, tattooed a message on his scalp and let his
hair regrow. The slave then travelled unchallenged to Aristagoras
,who was instructed to shave the slave's head, revealing the message
urging him to revolt against the Persians. In common with modern
steganography, it ensured that outsiders didn't know a secret message
existed.
But to experts, the idea al-Qaida would be passing steganographic
messages through TV broadcasts is ludicrous. "When they worked out
the tactics of the 9/11 perpetrators, what they did was get in a car,
drive some place and meet someone and have a conversation, they
didn't even get online," says Peter Honeyman, steganography expert
and scientific director of the centre for information technology
integration at the University of Michigan. "Why were the CIA
believing that they were seeing something in al-Jazeera broadcasts? I
can't fathom it."
The CIA had been using computers to look for hidden messages in the
headlines that scroll along the bottom of al-Jazeera broadcasts, a
feature used by most rolling news broadcasters. What the CIA was up
to found its way into the intelligence community rumour mill and got
back to the satellite channel.
"We were aware there were intelligence reports saying that al-Qaida
or its supporters might be communicating in ways that were
unconventional. There were certain whispers that perhaps they were
using al-Jazeera and other organisations, something we refuted
categorically," says Jihad Ballout, al-Jazeera's spokesman in Qatar.
"It's funny and it's frustrating at the same time as far as al-
Jazeera's concerned. We're fed up of these rumours that al-Jazeera is
a conduit for communication for any group."
Confirmation that the CIA had been hunting for hidden messages in
broadcasts - and had turned up some curious results - came in June
when US officials talked to NBC News. During the interview, the
officials told how technicians at the CIA's directorate of science
and technology believed they had found numbers embedded in al-
Jazeera's news strip that corresponded with a hotch-potch of targets.
There were dates and flight numbers, coordinates for high-profile
sites such as the White House, as well as information apparently
pointing to the small town of Tappahannock, Virginia.
Security experts have developed several ways to embed messages in
images and video streams. One of the simplest methods is to take a
frame of an image made up of pixels and alter it very slightly.
"Every pixel is represented by three colours - red, green and blue -
and each has a value from zero to 255 that represents the intensity
of that colour. It turns out you can change the bits, make an odd
number even, and an even number odd, which changes the perceived
colour so little, it's difficult to tell anything's been done to it,"
says Honeyman, who adds that a megapixel-sized image could carry a
secret message of 50,000 words.
The problem with hunting messages hidden by steganography is that
there are so few of them, any computer program will come up with
false positives - messages that aren't really there. "The false
positive rate, even if it's vanishingly small, starts to throw
signals at you that makes you want to believe you're seeing messages.
And somebody could be fooled by that if they didn't understand the
nature of steganography," says Honeyman.
When NBC News broke the story that the CIA's intelligence was
unreliable, employees at al-Jazeera were delighted, according to
Ballout, but he has concerns, too. "I'm glad it has been brought out
into the open, but this is very risky for the media at large. If this
perception was to be perpetuated, the media is at risk of being
dragged into an area where it loses its objectivity and is considered
to be party to a conflict," says Ballout. "That public policy can be
swayed by something like this - getting it absolutely wrong- just
imagine where this could lead. We've suffered a great deal. All the
allegations against al-Jazeera, one would have to question what was
driving them."
Honeyman says this isn't the first time fears have been raised of
terrorists using steganographic messages. After the 9/11 attack,
Honeyman and a student investigated press reports that al-Qaida was
hiding messages in images on the internet. Together, they analysed
millions of images. "We hunted and hunted and hunted, but we found
zero, nothing, not even a 'meet me at the Starlight Lounge at 11'."
"We're dealing with the global fear of terrorism, which is
legitimate, but that fear is being translated into very speculative
and unrealistic scenarios, all of which are possible, but none of
which are likely. Until someone turns over some evidence that says
'here's the cover message, here's the hidden message,' I'm going to
remain a sceptic that terrorists are using this," says Honeyman.
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