Read about B.P.'s storied history, learn about upcoming events and how you can volunteer at the museum today, access a detailed list of links related to codebreaking, and find out more about B.P. on this charity's thorough and well-illustrated Web site.

The home page of Bletchley Park, self-described as "Britain's Best Kept Secret," offers detailed information on this fascinating museum as well as on the Enigma machine, the Lorenz cipher machines, the Colossus, and other devices used to make and break codes during World War II. You can even try your hand at cracking codes for B.P. today.

Founded in the 1920's, this nonprofit volunteer organization is devoted to disseminating cryptographic knowledge. Members construct problems in classical cipher systems for other members to solve without knowing the secret key. The site provides information on joining, examples of cryptograms, and electronic versions of the organization's newsletter.

Established in 1993 to provide a "peek behind the curtain" at this once-secret world, this museum's Web site offers information on the institution as well as selections from its exhibits.

This site answers many of the questions asked frequently about cryptography, cryptology, secret codes, ciphers, and digital signatures. It also has a list of cryptological references, journals, and books.

This Web site is devoted to Alan Turing, the fascinating man who helped to crack the Enigma.

This page offers a nice collection of resources related to the Enigma machine. Included are articles, a downloadable cryptography course, and an electronic simulation of the Enigma.

Singh, who directed the NOVA program "The Proof," based on his bestselling book Fermat's Enigma, delves into the history and complexities of codes and ciphers as only one with a doctorate in physics can do well. Includes a Cipher Challenge with a $15,000 award (deadline 10/1/2000).

For those who want to delve more deeply into what transpired at Bletchley Park, written by the individuals whom Churchill described as the "secret weapon" that "won the war" - the men and women who worked there. Chapters on the various huts, bombes, and codes, including one on how the Enigma works.

A highly readable history of the codebreaking operations at Bletchley Park, interspersed with lively anecdotes told by the B.P.'s codebreakers and support staff. We excerpted this book for Mind of a Codebreaker.

This book is a comprehensive guide to sending information securely over the Internet. Managing secret keys, the basics of private- and public-key cryptography, securing electronic mail - all is covered extensively and complemented by helpful diagrams. Smith wrote Are Web Transactions Safe.