Digital Fortress (out of print)
When the NSA's invincible code-breaking machine- encounters a mysterious code it cannot break, the agency calls in its head cryptographer, Susan Fletcher, a brilliant and beautiful mathematician. What she uncovers sends shock waves through the corridors of power. The NSA is being held hostage... not by guns or bombs, but by a code so ingeniously complex that if released it will cripple U.S. intelligence. Caught in an accelerating tempest of secrecy and lies, Fletcher battles to save the agency she believes in. Betrayed on all sides she finds herself fighting not only for her country, but for her life, and ultimately, for the life of the man she loves. From the underground hallways of power, to the skyscrapers of Tokyo, to the towering cathedrals of Spain, with a startling twist that leaves the agency scrambling to avert the biggest intelligence disaster in U.S. history, Digital Fortress never lets up. First published 1998.