Digital Fortress is a novel by American author Dan Brown and published in 1998 by St. Martin's Press (ISBN 0-312-26312-0). Digital Fortress book cover This image is a book cover. ... This article is about the writer. ... For other uses, see Country (disambiguation). ... The English language is a West Germanic language that originates in England. ... Some notable science fiction novels, in alphabetical order by title: 20,000 Leagues Under the Sea by Jules Verne 2001: A Space Odyssey by Arthur C. Clarke 334 by Thomas M. Disch An Age by Brian Aldiss The Andromeda Strain by Michael Crichton The Atrocity Exhibition by J.G. Ballard... Techno-thrillers are a hybrid genre, drawing subject matter generally from spy thrillers, war novels, and science fiction. ... A publisher is a person or entity which engages in the act of publishing. ... Headquartered in the legendary Flatiron Building in New York City, St. ... Hardcover books A hardcover (or hardback or hardbound) is a book bound with rigid protective covers (typically of cardboard covered with cloth, heavy paper, or sometimes leather). ... To meet Wikipedias quality standards, this article may require cleanup. ... ISBN redirects here. ... Wikibooks has a book on the topic of Angels and Demons Angels & Demons is a bestselling mystery novel by Dan Brown. ... This article is about the writer. ... Headquartered in the legendary Flatiron Building in New York City, St. ...

Plot summary

Susan Fletcher, a brilliant mathematician and head of the National Security Agency's (NSA's) cryptography division, finds herself faced with an unbreakable code resistant to brute-force attacks by the NSA's 3 million processor supercomputer dubbed "TRANSLTR". The code is written by Japanese cryptographer Ensei Tankado, a fired employee of the NSA, who is displeased with the agency's intrusion into people's privacy. Tankado auctions the algorithm on his website, threatening that his accomplice "North Dakota" will release the algorithm for free if he dies. Tankado is found dead in Seville, Spain. Fletcher, along with her fiancé, David Becker, a skilled linguist with eidetic memory, must find a solution to stop the spread of the code. Leonhard Euler, considered one of the greatest mathematicians of all time A mathematician is a person whose primary area of study and research is the field of mathematics. ... “NSA” redirects here. ... The German Lorenz cipher machine, used in World War II for encryption of very high-level general staff messages Cryptography (or cryptology; derived from Greek κρυπτός kryptós hidden, and the verb γράφω gráfo write or λεγειν legein to speak) is the study of message secrecy. ... In cryptanalysis, a brute force attack on a cipher is a brute-force search of the key space; that is, testing all possible keys, in an attempt to recover the plaintext used to produce a particular ciphertext. ... For other uses, see Supercomputer (disambiguation). ... For other uses, see Seville (disambiguation). ... For the journal, see Linguistics (journal). ... Eidetic memory, photographic memory, or total recall, is the ability to recall images, sounds, or objects in memory with extreme accuracy and in seemingly abundant volume. ...

Real life scenarios

The book is loosely based around the recent history of cryptography. In 1976 the Data Encryption Standard (DES) was approved with a 56-bit key rather than the 64-bit key originally proposed. It was widely reckoned that the National Security Agency had pushed through this reduction in security on the assumption that it could crack codes before anyone else. The German Lorenz cipher machine, used in World War II for encryption of very high-level general staff messages Cryptography (or cryptology; derived from Greek κρυπτός kryptós hidden, and the verb γράφω gráfo write or λεγειν legein to speak) is the study of message secrecy. ... Year 1976 Pick up sticks(MCMLXXVI) was a leap year starting on Thursday (link will display full calendar) of the Gregorian calendar. ... The Data Encryption Standard (DES) is a cipher (a method for encrypting information) selected as an official Federal Information Processing Standard (FIPS) for the United States in 1976, and which has subsequently enjoyed widespread use internationally. ... “NSA” redirects here. ...

In fact the DES was first publicly broken in 1997, 96 days after the first of the DES Challenges. In 1998, the same year as Digital Fortress was published, the Electronic Frontier Foundation (featured in the book) built a piece of hardware costing less than $250,000 called the EFF DES cracker which broke it in 56 hours. For the band, see 1997 (band). ... Part of the EFFs DES cracking machine which was used in two of the challenges The DES Challenges were a series of contests created by RSA Security for the purpose of highlighting the security provided by the Data Encryption Standard. ... Year 1998 (MCMXCVIII) was a common year starting on Thursday (link will display full 1998 Gregorian calendar). ... EFF Logo The Electronic Frontier Foundation (EFF) is an international non-profit advocacy and legal organization based in the United States with the stated purpose of being dedicated to preserving free speech rights such as those protected by the First Amendment to the United States Constitution in the context of... The EFFs US$250,000 DES cracking machine contained over 18,000 custom chips and could brute force a DES key in a matter of days — the photo shows a DES Cracker circuit board fitted with several Deep Crack chips In cryptography, the EFF DES cracker (nicknamed Deep...

The brute force search used by TRANSLTR takes twice as long for each extra bit added to the key (if this is done sensibly), so the reaction of the industry has understandably been to lengthen the key. The Advanced Encryption Standard established in 2001 uses 128, 192 or 256 bits, which take at least 10²¹ times as long to solve by this technique. In computer science, a brute-force search consists of systematically enumerating every possible solution of a problem until a solution is found, or all possible solutions have been exhausted. ... In cryptography, the Advanced Encryption Standard (AES), also known as Rijndael, is a block cipher adopted as an encryption standard by the U.S. government. ...

Unbreakable codes are not new to the industry. The One-time pad, invented in 1917 and used by the Russians for many years, was proved to be unbreakable by Claude Shannon in 1949, when used correctly. However it is inconvenient and expensive to use in practice and its use is generally limited to government and military agencies. Excerpt from a one-time pad. ... Claude Shannon Claude Elwood Shannon (April 30, 1916 – February 24, 2001), an American electrical engineer and mathematician, has been called the father of information theory,[1] and was the founder of practical digital circuit design theory. ... Year 1949 (MCMXLIX) was a common year starting on Saturday (link will display the full calendar) of the Gregorian calendar. ...

Public-key cryptography does not generally use fixed length keys and is not susceptible to the computer described in Digital Fortress although it is not unbreakable and may be broken in the future using quantum computing techniques. A big random number is used to make a public-key pair. ... Shors algorithm is a quantum algorithm for factoring an integer N in O((log N)3) time and O(log N) space, named after Peter Shor. ...

Code solution

The code that appears in the end of the book

128-10-93-85-10-128-98-112-6-6-25-126-39-1-68-78

is decrypted by looking at the first letter of the chapter for each number. For example, chapter 128 starts 'When Susan awoke'. The resulting text is

WECGEWHYAAIORTNU

Decryption is performed using a columnar transposition cipher, termed a "Caesar Square" cipher in the book (this is unrelated to the Caesar cipher). The letters are arranged into a square: In classical cryptography, a transposition cipher changes one character from the plaintext to another (to decrypt the reverse is done). ... The action of a Caesar cipher is to replace each plaintext letter with one a fixed number of places down the alphabet. ...

W E C G

E W H Y

A A I O

R T N U

and read from the top down.

WEAREWATCHINGYOU

Add spaces and you get the plaintext, This article is about cryptography. ...

"We are watching you"

a reference to the NSA's monitoring systems.

Notes

• One briefly described character is mentioned as an alumnus of Amherst College, which Brown graduated in 1986.
• Mr. Brown makes a significant error when describing a climactic chase scene up the Giralda tower of the Cathedral in Sevilla. Though he describes Becker as dashing up the stairs of the Giralda, one of the well-known features of this tower is that it has no stairs leading to the top, but a series of ramps.
• Another error appears in the 2004 Corgi paperback edition, on page 143 the assassin Holuhot transmits the message "SUBJECT: P. CLOUCHARDE - TERMINATED", but on page 425 the list of messages reads "SUBJECT: PIERRE CLOUCHARDE - TERMINATED". It is unknown if this error appears in other editions of the book.
• The same error appears on pages 113 and 357, respectively, in the St. Martin's Paperbacks 2004 edition.

Amherst College is a private liberal arts college in Amherst, Massachusetts, USA. It is the third oldest college in Massachusetts. ...

External links

• Digital Fortress page at Mathematical Fiction Alex Kasman's site includes a forum, critique of the math/computing, and his solution to the code.
• Rob Slade's review of Digital Fortress The book is reviewed "on the basis of technology, including the fiction".
• (Spanish) Criticism in the Spanish-language Epoca of the book's description of locations in Seville