“People need to realize that there are many ways for the government to get vast amounts of e-mail,” said Chris Soghoian, a technology expert with the American Civil Liberties Union.
Controlling the data flow
The drive for new intelligence sources after the Sept. 11, 2001, attacks relied on a key insight: American companies controlled most of the Internet’s essential pipes, giving ample opportunities to tap the torrents of data flowing by. Even terrorists bent on destruction of the United States, it turned out, talked to each other on Web-based programs such as Microsoft’s Hotmail.
Yet even data not handled by U.S.-based companies generally flowed across parts of the American telecommunications infrastructure. Most important were the fiber-optic cables that largely have replaced the copper telephone wires and the satellite and microwave transmissions that, in an earlier era, were the most important targets for government surveillance.
Fiber-optic cables, many of which lie along the ocean floor, provide higher-quality transmission and greater capacity than earlier technology, with the latest able to carry thousands of gigabits per second.
The world’s hundreds of undersea cables now carry 99 percent of all intercontinental data, a category that includes most international phone calls, as well, says TeleGeography, a global research firm.
The fiber-optic networks have become a rich source of data for intelligence agencies. The Guardian newspaper reported last month that the Government Communications Headquarters, the British equivalent of the NSA, taps and stores data flowing through the fiber-optic cables touching that nation, a major transit point for data between Europe and the Americas. That program, code-named Tempora, shares data with the NSA, the newspaper said.
Tapping undersea transmission cables had been a key U.S. surveillance tactic for decades, dating back to the era when copper lines carrying sensitive telephone communications could be accessed by listening devices divers could place on the outside of a cable’s housing, said naval historian Norman Polmar, author of “Spy Book: The Encyclopedia of Espionage.”
“The U.S. has had four submarines that have been outfitted for these special missions,” he said.
But the fiber-optic lines — each no thicker than a quarter — were far more difficult to tap successfully than earlier generations of undersea technology, and interception operations ran the risk of alerting cable operators that their network had been breached.