Something that I thought of is that the bigram repeat @ period 15 (340 mirrored) and 19 can be seen as a legal chess move by the knight piece. Or that the 340 is possibly using a "Knight’s tour" transposition matrix. https://en.wikipedia.org/wiki/Knight%27s_tour
This "Knight’s Tour" encipherment scheme is mentioned in Helen Gaine’s "Elementary Cryptanalysis" first published in 1939.
Curiously, another book with the same title by Sinkov claims that Gaines’ book was the only other one on cryptanalysis available in English in 1966. Considering that there are many other books on the subject mentioned here, I wonder what is meant? Was Gaines’ book the most well-known?
Here’s an example of a Knight’s Tour cipher:
Jarlve:
Please excuse my ignorance on the decipherment topic. I’ve been trying to follow the discussions, but there is a bit of a learning curve. Assuming your hypothesis on the knight’s tour transpo matrix is correct, have any attempts been made to break down the 340 into 4-8×8 grids (chess board dimensions) with 1 column and 4 rows as filler? This would fit with the Halloween card cross with the four different sections.
Something that I thought of is that the bigram repeat @ period 15 (340 mirrored) and 19 can be seen as a legal chess move by the knight piece. Or that the 340 is possibly using a "Knight’s tour" transposition matrix. https://en.wikipedia.org/wiki/Knight%27s_tour
@Barry S.,
Not that I know of but there’s so many ways, so many things… you can reconfigure the cipher in 340! unique ways (transposition wise). That’s a number with 715 digits. So we go were our nose is. I wanted to leave this theory here because it seemed interesting (in relation to the bigram thing and also in relation to the claim of GM S.V.) for anyone who wants to work on it and I may work on it in the future if our current road leads to a dead end.
@Barry S.,
Not that I know of but there’s so many ways, so many things… you can reconfigure the cipher in 340! unique ways (transposition wise). That’s a number with 715 digits. So we go were our nose is. I wanted to leave this theory here because it seemed interesting (in relation to the bigram thing and also in relation to the claim of GM S.V.) for anyone who wants to work on it and I may work on it in the future if our current road leads to a dead end.
Alright, I’ll play with it. Already there seems to be some interesting clumping of symbols applying the "knight’s tour" to the top left corner (excluding the top row and middle column of the 340 as filler).
