Digital Fortress is a novel written by Dan Brown. Digital Fortress offers many entertaining twists and mystical storylines. The story begins with the introduction of Susan Fletcher, a cryptographer who works at the NSA, and her fiancé, David Becker, a language professor who enjoys playing racquetball. Trevor Strathmore is the head of the NSA's cryptography department and has found what he believes to be unbreakable code, developed by former NSA employee Ensei Tankado. The NSA has a supercomputer called TRANSLTR, which can crack any encrypted code in less than five minutes. Susan is called by Strathmore because there is an emergency. Strathmore tells Susan that TRANSLTR has become obsolete. At first she doesn't believe him, but Strathmore then shows Susan that the TRANSLTR has been trying to crack the code for over fifteen hours. When Strathmore contacted Tankado to stop publication, he refused and Tankado put a free download on his website. However, no one can open the file until Tankado gives the file's password, which is auctioned off to the highest bidder. He also threatens that if anything happened to him, an anonymous third party called "North Dakota" would leak it to everyone. Tankado is later found dead in Spain, where Becker is sent to retrieve a ring he owned and what they believe to be the access code to unlock the digital fortress. In an attempt to discover Tankado's third-party partner before news of Tankado's death spreads, Strathmore asks Susan to put a tracer on the North Dakota email account, or "ndakota", that has been set up on an anonymous server. Susan quickly discovers that Strathmore has sent David to Spain. Strathmore believes Tanka... middle of paper ......id and she thinks David is dead. Strathmore fails to stop TRANSLTR in time, and it explodes, killing him. Susan manages to escape but fears for her fiancé. The NSA director brings Susan to the main data bank, where the virus is attacking and everyone is trying to find the destruction code. She tells everyone that the code is written on the ring that David found, and the NSA director contacts the two agents who are holding David, and Susan sees her fiancé alive. They discover that the code doesn't work and Susan finds a puzzle in the program to stop it. The code is number 3. They were able to discover it thanks to the difference between the Hiroshima nuclear bomb, isotope 235, and the Nagasaki nuclear bomb, isotope 238. These are the bombs that killed the mother by Tankado. The database is backed up before hackers can obtain classified information.