d'Agapeyeff cipher

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):
 
Here is a cryptogram upon which the reader is invited to test his skill.
 
75628 28591 62916 48164 91748 58464 74748 28483 81638 18174
74826 26475 83828 49175 74658 37575 75936 36565 81638 17585
75756 46282 92857 46382 75748 38165 81848 56485 64858 56382
72628 36281 81728 16463 75828 16483 63828 58163 63630 47481
91918 46385 84656 48565 62946 26285 91859 17491 72756 46575
71658 36264 74818 28462 82649 18193 65626 48484 91838 57491
81657 27483 83858 28364 62726 26562 83759 27263 82827 27283
82858 47582 81837 28462 82837 58164 75748 58162 92000
 
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

Update History:

April 24, 2010
    - Minor edit

April 11, 2010
    - Added photo of cipher from the original 1939 edition of
Codes and Ciphers - A History of Cryptography
    - Added links to the Attack strategies and Other perspectives pages

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