lock on the code room -- a small, windowless space secured for secret communications, a standard feature of most embassies -- and the team swept inside. Groat opened the safe within 15 minutes, having practiced on a similar model back in the States. The woman and two other officers were trained in photography and what the CIA calls "flaps and seals"; they carefully opened and photographed the code books and one-time pads, or booklets of random numbers used to create almost unbreakable codes, and then resealed each document and replaced it in the safe exactly as it had been before. Two hours after entering the embassy, they were gone. After dropping the break-in specialists off at their hotel, the driver took the photographs to the U.S. Embassy, where they were sent to CIA headquarters by diplomatic pouch. The next morning, the team flew out. The CIA is not in the habit of discussing its clandestine operations, but the agency's purpose is clear enough. As then-chief James Woolsey said in a 1994 speech to former intelligence operatives: "What we really exist for is stealing secrets." Indeed, the agency declined to comment for this article, but over the course of more than 80 interviews, 25 people -- including more than a dozen former agency officers -- described the workings of a secret CIA unit that employed Groat and specialized in stealing codes, the most guarded secrets of any nation. What Groat and his crew were doing followed in the tradition of all