WASHINGTON – Despite warnings from top government officials that terrorists would use exotic technology to communicate, suspected terrorist mastermind Usama bin Laden instead has used "no-tech" methods, foiling efforts to track him, former U.S. intelligence officials said.
But there are some lingering electronic trails by his suspected operatives being investigated by federal officials looking at how last week's attackers used e-mail and the Internet.
Intelligence agents once could keep tabs on bin Laden when he used a satellite phone that could be picked up by U.S. spy gear and matched to his voiceprint. That capability leaked to bin Laden, so he swore off talking on the phone, according to Marc Enger, former director of operations at the Air Intelligence Agency, the Air Force's intelligence arm.
"So he switched a lot of communications technologies," Enger said. "Unfortunately, now it is other people talking for him. In an innocuous conversation, you can't pick that out."
Bin Laden relies on human messengers, safe houses and close-knit groups such as family members to send out his directives.
"This isn't low-tech," said Wayne Madsen, a former communications specialist for the National Security Agency. "You'd have to really call it no-tech."
Investigators think some of the hijackers may not have been as wary of high-tech communications as bin Laden, whom the United States considers the prime suspect in the attacks.
After the attacks last week, investigators began working with major Internet service providers like Earthlink and America Online to get information about the hijackers' Internet habits. In Britain, law enforcement agencies have asked Internet companies to keep traffic logs to look for clues to the attacks.
In March 2000, the CIA has warned about terrorist organizations using secure Internet communications. CIA Director George Tenet told the Senate then that several terrorist groups, including bin Laden's al-Qaida, "are using computerized files, e-mail and encryption to support their operations."
"Terrorists also are embracing the opportunities offered by recent leaps in information technology," Tenet said.
Madsen said the hijackers could have communicated by means of seemingly innocuous messages on Web sites, impervious to the most vaunted surveillance tools in use by U.S. intelligence.
"There might some minor change to a Web site that would indicate a plan, because they knew it in advance. All the Carnivores and all the Echelons in the world would do very little to hamper that kind of operation," referring to the FBI's e-mail surveillance box and a widely suspected NSA surveillance network.
Enger said some U.S. agents have reported bin Laden has used steganography — the art of hiding a message in plain sight, such as a text message hidden in a picture file — and pornography Web sites to communicate. Enger said those sites would be considered unlikely hiding places for a devout Muslim like bin Laden.
The use of racy pictures loaded with hidden messages is extremely difficult to verify because the investigator first would have to know the message was there, Enger said. Decrypting it presents another problem.
"Unless you have the original photo file, you can't compare to see if they've been changed," Enger said. He said the United States has looked for new technology to overcome that hurdle.
While the free, powerful encryption software available through the Internet presents somewhat of a hurdle, that a message is encrypted can tip off authorities. Sometimes, they also can figure out the sender and recipient of the message even if the message itself is coded.
Former NSA technician Madsen said the United States battled another low-tech foe in recent years: Mohamed Farah Aidid, a Somalian warlord who was the target of U.S. forces in 1993. Madsen said that instead of phones, Aidid's forces banged out messages on drums.
"Spy satellites can't pick that kind of stuff up," Madsen said.