[Blog Post] Spatial Spread And Conditional Character Entropy Reduction

[nablator]

It uses the Polybius Square as a kind of gameboard, and instead of enciphering characters consistently by their coordinates, it enciphers the paths taken by a token around the board to get from one point to another.  By repeating the same "moves" on a similar board, a reader can reconstruct the plaintext.

Nice. I invented a "path" cipher too. Unlike the rail fence (zigzag) cipher the path is variable and many paths are possible.

Maybe it's time to reveal how I did my experiment back in 2017. I kept Voynichese glyphs for coordinates, but changed the "pick the letter at the cartesian coordinates given by the ciphertext" rule to something that may be called antipolybius: to decipher, pick Latin letters on the board at every cell on the zigzag path defined by the ciphertext stream *except* at the vertices. The game is played on a large, mostly empty board, with one or several Latin alphabets written on the cells. With highly optimized keys (choice of coordinates and board content) it generated relatively convincing simili-Voynichese: You are not allowed to view links. Register or Login to view.

Humans are good at path-finding so the enciphering game could be fun. Lots of variations are possible: find the shortest path despite different obstructions on each page, or: avoid straying off the beaten path as much as possible, etc.

But something was very wrong: almost half of the vocabulary found in the VM could not be used. I guess I should try and find special rules for [ch], [Sh] and gallows and reduce the size of the board accordingly.