The Secret History of the National Security Agency

Intelligence historian Matthew Aid talks to U.S. News about his new book.

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The National Security Agency is one of the most secretive fiefdoms inside the American government and is probably familiar to most people only as the guys who may or may not be listening to your phone calls and reading your E-mails as they surveil terrorists.

Intelligence historian Matthew Aid has spent the past quarter century prying loose NSA documents through the Freedom of Information Act and interviewing current and former agency employees. He recently chatted with U.S. News about his new book, The Secret Sentry: The Untold History of the National Security Agency. Excerpts:

What does the NSA do?

The NSA is the U.S. government's eavesdropping agency, with an annual budget of $8 billion. It spies on all foreign communications, and it also encodes U.S. government communications. About 75 percent of its budget is spent on vacuuming up outside communications, and about 25 percent goes to protecting U.S. government communications. The protection of U.S. communications has become more important as more and more hackers try to break into everything from the power grids to the Pentagon's E-mail network.

Does the NSA have offensive capabilities?

Since 9/11, the military has gone out and recruited a small but important group of technically minded people, very young people, who can break into our enemies' communications systems. They are now a group at NSA working what's called Tailored Access Operations.

Working with the CIA and others, TAO identifies computer systems and networks being used by foreign 

terrorists. Then, a small group of computer hackers belonging to the U.S. Navy, who call themselves Computer Network Exploitation operators, break into the systems electronically to steal the information contained on the hard drives, as well as monitor the E-mail traffic coming in and out of the computer. Just listening?

When a military commander asks NSA to jam Taliban communications or bring down an Iraqi insurgent website, it drives the NSA people absolutely bonkers. They don't want to go around putting viruses on an al Qaeda laptop. In fact, they don't want to leave any evidence that they've been snooping at all. All the NSA wants to do is listen. There's a never-ending battle between the listeners and the disrupters in the wake of 9/11, and it won't be resolved anytime soon.

How important is NSA compared with, say, the CIA?

There's really no comparing them. The NSA has admitted that on 9/11, more than 60 percent of the material inside the President's Daily Brief [the highly classified national security report] came

from signals intelligence. That percent age is undoubtedly higher today. Human intelligence by nature isn't that comprehensive or reliable.  Yet there have been some staggering blunders because of signals intercepts. During the Gulf of Tonkin [incident in August 1964], the NSA intercepted signals showing that the North Vietnamese had attacked a U.S. destroyer. It concluded that they were live reports from a battle. They reported that information

up the chain of command. Only many, many years later did the NSA go back and listen to the original material. What they found was that they had intercepted Vietnamese radio operators giving a post
mortem of a battle which occurred two days earlier. It was one of the greatest intelligence mistakes in history. OK, now let's hear about a success.

In [October] 1964, China was about to detonate their first atomic bomb. The U.S. was well prepared because the NSA was intercepting communications from Chinese transport planes flying VIPs to

the site. They were also intercepting weather forecasts around the test site. Then Secretary of State Dean Rusk strode into the pressroom and told the reporters that he had intelligence that China was 48 hours away from detonating a bomb. The NSA went crazy. The Chinese immediately shut down all their radio traffic, and all the sources were lost. Because of that and other incidents, the NSA still refuses to provide anyone with the raw transcripts of the intercepted communications. It's been a bone of contention be