Reply To: Challenge 10B
If you use a hill climbing algorithm you get the entire grid in one go – the book by Madness is available to download from the page “BOSS Training Division”, the link is at the top of the page, just under the image of some books and is titled “A book on Classical Cryptography” and has information on how to do this although not specifically on a modified four square cipher (although the principle is the same). As it would take sometime to work through his book this is probably more useful information to be used in preparation for next years competition.