Digital Fortress by Dan Brown in Paperback

 

The National Security Agency, located in Fort Meade, Maryland, faces a daunting challenge when their powerful code-breaking machine is stumped by a mysterious code. In a race against time, they turn to their best cryptographer, Susan Fletcher, a brilliant and beautiful mathematician, to crack the code and discover the shocking truth behind it. As she delves deeper, she realizes that the NSA is under threat not by weapons, but by a complex and dangerous code that could cripple US intelligence. In Seville, Spain, the creator of the code, Ensei Tankado, is found dead, taking with him the key to an impenetrable formula that could shift the balance of power forever. From the halls of power to the streets of Tokyo and the grand cathedrals of Spain, a desperate race ensues. Amidst a web of lies and treachery, Susan fights not only for her country, but for her life and the life of the man she loves.