Written by Alexander d'Agapeyeff, the plaintext remains a mystery after more than 70 years of attempts to solve it from amateurs and professional cryptanalysts alike. It can be commonly found listed among other famous unsolved ciphers although published information is scarce.
The cipher appeared on the 1939 (first edition, Oxford University Press) of Alexander D'Agapeyeff's book Codes and Ciphers - A History of Cryptography. It was presented as an invitation for the reader to test his skills at breaking ciphers.
The author reportedly received several letters from readers exposing their difficulty in tackling the challenge, but D'Agapeyeff himself reportedly could not seem to recall how to solve the cryptogram. The cipher has since been left out of the later editions.
Here is the cipher as it appeared on the last page of Codes and Ciphers (see a photo):
Although (as-yet) unsolved, there are a lot of phenomena noted on this cipher. You may refer to the Cipher Analysis page for a lot more information.
It is my hope that providing a systematized approach to the cipher it may attract more would-be solvers to try and tackle it.
You can see my comments on other theories on the Other Perspectives page.
I finally had the time to complete the first draft of the Attack Strategies page. Note that I've still to proof read that section so some mistakes have probably crept in and have gone unnoticed. I'll be cleaning up the article in the upcoming days and complementing it with some more details.
I have been receiving a few emails from individuals interested in this cipher. Please keep the mails coming as they've been both a good source of inputs and also motivation to update this site with the most up to date and factual information possible. Thanks for all contributions so far!
Page created: March 20, 2010 by Tiago Rodrigues