Submarines prowl the ocean floor, while ships above carefully skirt the limits of international waters. On dry land, guards patrol high fences surrounding acres of huge golf ball-shaped radar domes. In the skies, airplanes knife through the stratosphere, while higher up orbiting electronic ears listen to whispers from the planet below.
They're all trolling a vast sea of electromagnetic signals in hopes of catching a terrorist plot in the making, a shady arms deal, economic intelligence, or a rogue nation building a weapon of mass destruction. This so-called signals intelligence, or Sigint, has been vital to the United States and its allies for decades. But, in the wake of 9/11 and the failure to capture Osama bin Laden, the shortcomings of the world's biggest interception system are apparent.
The ships, planes, antennas, and satellites are the result of a triumph of Cold War engineering, designed to keep tabs on the Soviet Union and its allies. The question now is: how useful is the system against terrorists who know not to trust their satellite phones? How effective can it be in an age when almost untappable fiber-optic lines carry information at stupefying rates and cheap, off-the-shelf encryption systems can stump the most powerful supercomputers on earth?
Given the veil of secrecy drawn by nations around their intelligence operations, these questions might seem unanswerable, but even top-secret agencies have to operate in the real world, making it possible to draw some conclusions.
Those findings paint an intriguing picture of modern Sigint, in which the best way past a tough problem can be to solve a different one. Rather than the creation of ever more sensitive receivers or code-breaking computers, the hot areas of cloak-and-dagger information gathering include tapping fiber-optic cables (even at the bottom of the sea); using tiny bugging devices and old fashioned bribery, blackmail, and burglary to get at data before it has been encrypted; exploiting software flaws and poorly configured communications systems to bypass data-security measures; and automatically winnowing the vast amounts of intercepted communications.
Big brother or white elephant?
The old workhorse surveillance system described above is run by the United States—with the United Kingdom, Canada, Australia, and New Zealand as junior partners—under the secret 1947 UKUSA agreement. Often referred to as Echelon in the popular press, some fear it as the ultimate Big Brother: listening in on every telephone conversation, reading every e-mail, tracking every Web surfer around the globe.
But these fears are greatly exaggerated, explains Gerhard Schmid, vice president of the European Parliament and rapporteur of a 2001 report to the parliament on the UKUSA system. Schmid notes an obvious fact that many seem to forget: only those communications that the system has access to in some way can be intercepted. "There is no special magic physics for secret services....The rest is movie stories, rumors, and nonsense," says Schmid.
In effect, whether or not the Sigint system is of value boils down to a technical question: in the face of a telecommunications explosion that has brought e-mail, cellphones, beepers, instant messaging, fiber-optic cables, faxes, videoconferencing, and the World Wide Web to every corner of the globe, can the UKUSA intelligence agencies attain enough access to know what's going on?
Of course, some communications are easier to access than others. Wireless communications in particular offer two key advantages—you can intercept them without physically tapping into the target's communications system, and there is no way to detect that they have been intercepted. "Microwave, radio, telephone, walkie-talkie—communications that are in the air are all interceptible by some sort of antenna in the right place," says Jeffrey T. Richelson, author of The U.S. Intelligence Community (Westview Press, Boulder, Colo., 1999).
Much of the UKUSA system's physical assets around the world and orbiting above it are devoted to making sure there is an antenna in the right place. Listening posts of varying scale dot the earth—including on top of every U.S. embassy. Many are attached to military installations, while some are operated remotely. Others are mobile, on navy ships and submarines and on specially modified planes such as the EP-3 that crash-landed in China in 2001. For decades these eavesdroppers provided much of the intelligence community's Sigint.
But, for tactical and technical reasons, the well began to dry up at the start of the 1990s. The biggest tactical problem was that the Soviet Union's collapse kicked the legs out from under a monitoring network built up over decades. "There were some easy things about the Soviet Union," says James Bamford, author of Body of Secrets: Anatomy of the Ultra-Secret National Security Agency (Doubleday, New York, 2001). "The first one was you always knew where it was. You could invest a lot of money in a big listening post in Japan near Vladivostok because the Soviet navy was always going to be there."
Apart from being easily located on a map, the USSR also generated a steady stream of routine radio and microwave transmissions to provide grist for the intelligence wheel. "It's completely different when you're going after sporadic miniwars and terrorism," says Bamford.
The technical issues arose from the Internet-driven telecommunications explosion, the most serious consequence of which is the ever increasing shift toward fiber-optic-based international communications. The shift was due to the commercially attractive fact that one fiber can carry 128 times as much digital traffic as a satellite transponder—over 240 000 channels, each carrying 64 kb/s.