D'Agapeyeff Cipher (Part 2)

❚ I don't know why, but in the last days I used my spare time to think about the good old D'Agapeyeff Cipher.

      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

Remark: In the first post, i wrote that the puzzle only appeared in the 1939 version of the book but meanwhile i got new information. The puzzle is still contained in the reprinted version from 1949. The first version that comes without the puzzle is the version that was published in 1952.

Note that the puzzle was not altered in any way in the 1949 reprint. This can be seen as a clue, that D'Agapeyeff still believes that the puzzle itself was correct (e.g., not printed in a erroneous way).

D'Agapeyeff Cipher (Part 1)

The 1939 edition of D'Agapeyeff's book

Alexander D'Agapeyeff was a Russian-born cartographer who lived most of his life in London. He became famous for his excercise cipher, he left for the readers on the last page of the first edition of his book "Codes and Ciphers" published in 1939.

In the later revisions of his book, he removed this exercise. The reason, he said, was that he had forgotten how he did the encryption.

Perhaps he has not really forgotten how to do it, but he has made some mistakes that prevent him and everyone else from deciphering the message.

What makes me a little angry is that he did not reveal what he remembered. He probably still knew what method he was supposed to have used and some of the words that were in the message. Just as he knew that many people were working on a solution, why did he not support them with a little information?

The D'Agapeyeff cipher is one of those ciphers, from which is believed that it is no hoax, but a serious challenge to the cryptanalysists. Since Alexander was not a cryptologist, it is assumed that he used a cipher method from his book, or perhaps a combination of them. The cipher was also mentioned in various journal publications, like the Cryptologica [1] or the Cryptogram [2].

D'Agapeyeff cipher:

      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