Digital Fortress

Before the multi-million, runaway bestseller The Da Vinci Code, Dan Brown set his razor-sharp research and storytelling skills on the most powerful intelligence organization on earth--the National Security Agency (NSA)--in this thrilling novel, Digital Fortress.

When the NSA's invincible code-breaking machine encounters a mysterious code it cannot break, the agency calls its head cryptographer, Susan Fletcher, a brilliant, beautiful mathematician. What she uncovers…