Despite a six-year effort to build trusted computer chips for military systems, the Pentagon now manufactures in secure facilities run by American companies only about 2 percent of the more than $3.5 billion of integrated circuits bought annually for use in military gear.
That shortfall is viewed with concern by current and former United States military and intelligence agency executives who argue that the menace of so-called Trojan horses hidden in equipment circuitry is among the most severe threats the nation faces in the event of a war in which communications and weaponry rely on computer technology.
As advanced systems like aircraft, missiles and radars have become dependent on their computing capabilities, the specter of subversion causing weapons to fail in times of crisis, or secretly corrupting crucial data, has come to haunt military planners.
Only one-fifth of all computer chips are now made in the United States, and just one-quarter of the chips based on the most advanced technologies are built here, I.B.M. executives say
Cyberwarfare analysts argue that while most computer security efforts have until now been focused on software, tampering with hardware circuitry may ultimately be an equally dangerous threat. That is because modern computer chips routinely comprise hundreds of millions, or even billions, of transistors. The increasing complexity means that subtle modifications in manufacturing or in the design of chips will be virtually impossible to detect.
“Compromised hardware is, almost literally, a time bomb, because the corruption occurs well before the attack,” Wesley K. Clark, a retired Army general, wrote in an article in Foreign Affairs magazine that warns of the risks the nation faces from insecure computer hardware.
In the future, and possibly already hidden in existing weapons, clandestine additions to electronic circuitry could open secret back doors that would let the makers in when the users were depending on the technology to function. Hidden kill switches could be included to make it possible to disable computer-controlled military equipment from a distance. Such switches could be used by an adversary or as a safeguard if the technology fell into enemy hands.
A Trojan horse kill switch may already have been used.
The United States has used a variety of Trojan horses, according to various sources.
In 2004, Thomas C. Reed, an Air Force secretary in the Reagan administration, wrote that the United States had successfully inserted a software Trojan horse into computing equipment that the Soviet Union had bought from Canadian suppliers. Used to control a Trans-Siberian gas pipeline, the doctored software failed, leading to a spectacular explosion in 1982.