Code experts say bin Laden could have hidden message

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War On Terrorism : The Nation

October 12, 2001|By Scott Shane | Scott Shane,SUN STAFF

Experts on codes said yesterday that it is conceivable that Osama bin Laden used a videotaped declaration shown on television worldwide to transmit a simple message by way of a primitive verbal or visual code to terrorist cells in the United States or other countries.

A prerecorded broadcast such as the one aired Sunday could not hide a lengthy or complicated message, they said. But such a message could be hidden in a photo, a rock music file or other innocuous-looking items posted on the Internet or sent by e-mail, using sophisticated, computerized techniques that bin Laden's associates may have used in the past.

The sudden interest of the world in the ancient art of steganography, or hidden messages, was prompted by a request Wednesday from Condoleezza Rice, President Bush's national security adviser, to television network executives not to broadcast in full any video statements from the terrorist financier or his al-Qaida group.

Yesterday, the White House expanded Rice's request to newspapers, which were asked not to print complete texts of communiques from bin Laden and his spokesmen.

"The request is to report the news to the American people," said White House spokesman Ari Fleischer. "But if you report [such a message] in its entirety, that could raise concerns that he's getting his pretaped, prepackaged message out ... putting it into the hands of people who can read it and see something in it."

In her conference call with network executives, Rice cited concerns that bin Laden's anti-American messages could inflame Muslim sympathizers around the world, the executives said later. But she also suggested that international television could convey hidden messages to terrorists, including signals for further attacks.

"The means of communications out of Afghanistan right now are rather limited. One way to communicate outside Afghanistan to followers is through Western media," Fleischer said Wednesday, though he added that the warning was based on "concern" about a hidden message rather than "hard indications."

Experts on steganography said yesterday that any message hidden in bin Laden's broadcasts would have to be part of a simple, prearranged code that could involve the clothing he wore, the position of his arms or the use of certain phrases.

"It's absolutely possible to put a hidden message into such a broadcast," said Peter Honeyman, a computer scientist at the University of Michigan. "It could be two `Allah akbars' by land, three `Allah akbars' by sea."

Honeyman said there is no way for terrorists to embed in a videotape for broadcast a more complex text message of the kind that can be hidden in a computer file. And while bin Laden might have used a simple code in the videotape, even airing or printing brief excerpts might inadvertently reveal it.

He expressed skepticism that such a message was in fact hidden in the bin Laden videotape. "I just don't buy it," he said.

But Ben Venzke, a security consultant who believes al-Qaida has used computerized steganography in the past, said he thought the White House request was reasonable and well-founded.

"I think there's a legitimate concern about transmitting some type of message to cells in this country," said Venzke, who runs IntelCenter, a private intelligence company in Alexandria, Va., and has advised government agencies. "It's a very low-tech method - wearing a watch, wearing certain clothing, saying a certain phrase - but it's very effective."

Venzke, who studies international terrorism, argued that simple signals may fit into the terror network's known method of operating.

He said the terrorist attacks attributed to al-Qaida, including the bombings of two U.S. embassies in East Africa, the attack on the USS Cole and the recent assaults on the World Trade Center and the Pentagon, all appear to have resulted from long planning. That suggests that the next attacks probably also have already been planned.

"What the terrorists in this country need to know is when to execute what they've already planned," Venzke said. "Or it could be target selection - designating one target for attack instead of another."

To read any hidden message probably would be impossible without the aid of an agent inside al-Qaida - or access to an al-Qaida code book. Authorities in Europe are poring over a notebook containing suspected codes that belonged to Kamel Daoudi, a 27-year-old computer student detained in Leicester, England, on Sept. 25 and sent back to France, where he had been living. Authorities have linked Daoudi to a terrorist cell that was allegedly plotting an attack on the U.S. Embassy in Paris and other American targets.

If bin Laden and his associates are using steganography, from the Greek for "covered writing," they are part of a military tradition as old as recorded history, said Louis Kruh, co-editor of Cryptologia, a quarterly journal on codes and ciphers.

"It goes back to ancient times," said Kruh, who owns a 1526 book on the subject.

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