The Cipher Challenge

The Cipher Challenge is a set of ten encrypted messages, which I placed at the end of The Code Book when it was first published in 1999. In addition to the intellectual reward of cracking all ten messages, there was a prize of $15,000 for the first person to solve the Challenge. The Challenge was eventually solved on October 7, 2000, after one year and one month of arduous effort by codebreakers, amateur and professional, around the world.

The Cipher Challenge remains as part of this book. There is no longer a prize associated with its solution, but I would encourage readers to decipher some of the messages. The ten stages were intended to grow in difficulty, although many codebreakers have felt that stage 3 is harder than stage 4. The ciphers used in the stages differ and progress through the ages, so the early ciphers are ancient and easy to break, whereas the latter stages employ modern ciphers and require a great deal more effort. In short, stages 1 to 4 are for the amateur, stages 5 to 8 are for the real enthusiast, and 9 and 10 are for those who are dedicated codebreakers.

If you want to know more about the Cipher Challenge, you can visit my own Web site (www.simonsingh.com), which offers a variety of information, including a link to a report written by the Cipher Challenge winners, Fredrik Almgren, Gunnar Andersson, Torbjorn Granlund, Lars Ivansson and Staffan Ulfberg. The report makes excellent reading, but please be aware that it, and other material on the Web site, does include spoilers that you might not want to see just yet.

The main aim of the Cipher Challenge was to excite people, to get them interested in cryptography and codebreaking. The fact that thousands of people took up the challenge is tremendously satisfying. Officially the Cipher Challenge is now over, but I hope that it will continue to generate some interest among new readers who want to test their codebreaking skills.

Good luck,
Simon Singh