The National Security Agency has spent the past eight years inching out of the shadows, courting public opinion and opening its doors in limited ways to win back wavering congressional support.
But since Sept. 11, the agency has reverted to a place of secrets and seclusion, as shut down to outsiders as it was at the height of the Cold War. Its focus has narrowed to one mission: finding Osama bin Laden and his terrorist followers.
The agency has called back more than 100 NSA veterans, most of them retired to nearby Howard and Anne Arundel counties. And at least that many employees have been sent abroad, according to one source, who said entire departments have been packed up and shipped to the Middle East.
A driver from a local transportation company that contracts with NSA and Fort Meade, who did not want to be identified, said it has driven numerous passengers to Baltimore-Washington International Airport. The passengers, loaded with equipment, asked to be picked up in parking lots in the suburbs rather than at their homes or at the agency.
NSA spokeswoman Judith Emmel said she couldn't comment on how many people might be abroad, but she said employees at the Fort Meade headquarters have been working around the clock.
"When people say they are going to meet at 8," she said, "you have to ask if they mean 8 in the morning or 8 at night."
Insiders say there are some who haven't left their offices since the attacks.
The agency has been searching for bin Laden for more than two years, since the U.S. embassy bombings in Africa in 1998.
Steve Uhrig, president of SWS Securities in Harford County, which provides intelligence and eavesdropping equipment to the NSA, said that before the attacks, he had sold the NSA a stash of "suitcase kits," portable listening devices best used against targets like the suspected terrorists.
The kits, which are disposable and last about six weeks, travel well over rugged terrain and can track low-powered radio transmissions - especially those produced by people hiding with generators and ham radios, he said
They can also help locate signals being "hidden" next to larger signals, Uhrig said.
This new equipment could be key to tracking down bin Laden in a place that doesn't use the kind of sophisticated telecommunications and satellite technology the agency is so adept at cracking.
Afghanistan, after decades of war and poverty, has few phone lines to tap or satellite links to eavesdrop on.
But the communications methods bin Laden and the terrorists use could be elusive.
"Anyone with a little computer understanding could get something up and running for him," Uhrig said. "If he kept his transmissions short, moved frequently, he could even put the transmitter 10 miles away from where he is, run a ground microwave relay to a hilltop and bounce it off a satellite, put it under an oil company's name. ... It could provide the perfect cover."
Defense Department officials say finding him is the agency's No. 1 priority.
"[The NSA] has anything and everything ... looking for signals of any kind," Uhrig said. "If you put enough people out there, someone is going to hear something."
Some of the employees sent abroad will likely set up a temporary listening facility in Pakistan and put into use its Emergency Reaction Team, a small group with sophisticated eavesdropping skills that can move quickly into any region, said James Bamford, author of two books on the agency.
Other NSA cryptologists and members of the other military intelligence agencies are already likely to be eavesdropping on signals from Afghanistan, from planes and ships in nearby waters, he said.
There are a lot of communications to intercept, Bamford said, "The problem is most signals are probably going to be dealing with things that aren't related to finding bin Laden."
Since the Cold War, the NSA had largely refocused its efforts from spying on the Soviet Union to helping the U.S. government in drug interdiction and monitoring worldwide financial transactions for bribes and extortion.
In recent years, the Department of Defense has closed many of the listening stations in and around the Middle Eastern region that were once used to target Russian communications, including plans announced earlier this year to shut down the Bad Aibling Station in Germany in September.
"Technology overcame them," said Tom A. Brooks, former director of naval intelligence. "High technology means more bounce, and satellites can collect that sort of thing for you. There was no longer a need to have a couple lonely guys sitting on a mountaintop in Iran."
Now, those mountaintops are looking rather inviting, Brooks said.
"There are things you can only get by being close," he said, adding that the NSA will also likely court the neighboring Uzbekistan and Tajikistan governments, which have years of experience tracking the Taliban, and enlist their help.
As intelligence efforts abroad accelerate, the agency at home has hundreds of employees working overtime searching for clues to locate bin Laden and help ground and air troops locate targets.
Just as life inside the agency has changed, so has its public image. For more than eight years, that image had been carefully crafted to present a more open agency.
At numerous events over the past several years, the agency has showcased the heroic efforts of some of its alumni and attended hundreds of job fairs to promote itself. While closed to visitors, the agency has taken pains to be a good neighbor, talking with Anne Arundel County officials about its plans and needs, such as additional security fencing that has been unpopular with neighbors.
But now concrete barricades block all but one entrance, and unmarked police cars pull up behind cars that linger on the side of the road. At the nearby Colony 7 Shell gas station, NSA employees, once chatty to station attendants, hide their agency badges and keep to themselves.
The letters on the sign directing drivers to Fort Meade from Interstate 95 have also been removed, although the "NSA employees only" exit sign on the Baltimore-Washington Parkway is still in place.
The agency has canceled more than a dozen public events, including lectures on site for former cryptologists.
It has also locked down its long-standing symbol of openness and goodwill - the National Cryptologic Museum. Citing a lack of security, an agency spokeswoman said last week that the museum won't reopen any time soon.
The facility, which opened in 1993 and has held events nearly every month for agency alumni and visitors for the past two years, sits outside the agency's perimeter security fence.
An NSA official explained the agency is attempting to "keep a low profile," adding that it "doesn't seem appropriate" to comment on the war effort or its involvement.