Digital Fortress

Susan explained that her interest in cryptography had started in junior high school. The president of the computer club, a towering eighth grader named Frank Gutmann, typed her a love poem and encrypted it with a number-substitution scheme. Susan begged to know what it said. Frank flirtatiously refused. Susan took the code home and stayed up all night with a flashlight under her covers until she figured out the secret-every number represented a letter. She carefully deciphered the code and watched in wonder as the seemingly random digits turned magically into beautiful poetry. In that instant, she knew she'd fallen in love-codes and cryptography would become her life.

Almost twenty years later, after getting her master's in mathematics from Johns Hopkins and studying number theory on a full scholarship from MIT, she submitted her doctoral thesis, Cryptographic Methods, Protocols, and Algorithms for Manual Applications. Apparently her professor was not the only one who read it; shortly afterward, Susan received a phone call and a plane ticket from the NSA.

Everyone in cryptography knew about the NSA; it was home to the best cryptographic minds on the planet. Each spring, as the private-sector firms descended on the brightest new minds in the workforce and offered obscene salaries and stock options, the NSA watched carefully, selected their targets, and then simply stepped in and doubled the best standing offer. What the NSA wanted, the NSA bought. Trembling with anticipation, Susan flew to Washington's Dulles International Airport where she was met by an NSA driver, who whisked her off to Fort Meade.

There were forty-one others who had received the same phone call that year. At twenty-eight, Susan was the youngest. She was also the only female. The visit turned out to be more of a public relations bonanza and a barrage of intelligence testing than an informational session. In the week that followed, Susan and six others where invited back. Although hesitant, Susan returned. The group was immediately separated. They underwent individual polygraph tests, background searches, handwriting analyses, and endless hours of interviews, including taped inquiries into their sexual orientations and practices. When the interviewer asked Susan if she'd ever engaged in sex with animals, she almost walked out, but somehow the mystery carried her through-the prospect of working on the cutting edge of code theory, entering "The Puzzle Palace," and becoming a member of the most secretive club in the world-the National Security Agency.

Becker sat riveted by her stories. "They actually asked you if you'd had sex with animals?"

Susan shrugged. "Part of the routine background check."

"Well…" Becker fought off a grin. "What did you say?"

She kicked him under the table. "I told them no!" Then she added, "And until last night, it was true."

***

In Susan's eyes, David was as close to perfect as she could imagine. He only had one unfortunate quality; every time they went out, he insisted on picking up the check. Susan hated seeing him lay down a full day's salary on dinner for two, but Becker was immovable. Susan learned not to protest, but it still bothered her. I make more money than I know what to do with, she thought. I should be paying.

Nonetheless, Susan decided that aside from David's outdated sense of chivalry, he was ideal. He was compassionate, smart, funny, and best of all, he had a sincere interest in her work. Whether it was during trips to the Smithsonian, bike rides, or burning spaghetti in Susan's kitchen, David was perpetually curious. Susan answered what questions she could and gave David the general, unclassified overview of the National Security Agency. What David heard enthralled him.

Founded by President Truman at 12:01 a.m. on November 4, 1952, the NSA had been the most clandestine intelligence agency in the world for almost fifty years. The NSA's seven-page inception doctrine laid out a very concise agenda: to protect U.S. government communications and to intercept the communications of foreign powers.

The roof of the NSA's main operations building was littered with over five hundred antennas, including two large radomes that looked like enormous golf balls. The building itself was mammoth-over two million square feet, twice the size of CIA headquarters. Inside were eight million feet of telephone wire and eighty thousand square feet of permanently sealed windows.

Susan told David about COMINT, the agency's global reconnaissance division-a mind-boggling collection of listening posts, satellites, spies, and wiretaps around the globe. Thousands of communiques and conversations were intercepted every day, and they were all sent to the NSA's analysts for decryption. The FBI, CIA, and U.S. foreign policy advisors all depended on the NSA's intelligence to make their decisions.

Becker was mesmerized. "And code-breaking? Where do you fit in?"