Methods need no introduction, they’re the meat and potatoes of cryptanalysis.

I know there are better ways of testing my hypotheses and I’m sure there’s some great math out there or computers or what-have-you but this is my plan so far.

Each experiment will consist of a transposed K4 text.  In this way, divers and sundry transpositions can be attempted in a clear, linear fashion.

These transposed texts will be tested across the Playfair, Bifid and Foursquare cipher systems.  If someone knows a different classic digraphic system, please let me know.

For Playfair I’ll use Rumkin’s Playfair solver.  These allow 1 keyword to be used.

For Bifid I’ll use Rumkin’s Bifid solver.  These allow 1 keyword to be used.

For Foursquare I’ll use Wilhelm Plotz’s Cipher Clerk.  These allow 2 keywords to be used.

I hope you didn’t think I was going to do them by hand?  I don’t really have 7 years to try everything out plus the chances of injecting significant human error into the process by doing it myself would be unacceptable.  For speedy, reliable results; I’ll trust a program.

So we’ve got an unlimited amount of transposed K4 text that can be funneled one at a time into the digraphic decryption.  This boils decryption down to one step, essentially, and will speed up the process.  The hope is not that I’ll blaze through a couple hundred and then decide it didn’t work.  The hope, which is not entirely unrealistic, is that a fragment of plaintext will be found in one of the iterations which will provide a lead on understanding the complete method.  It’s possible I’ll get it 100% right but I won’t hold my breath for something like that.  I’m initially planning on 10 attempts and then an evaluation to see if it’s worth continuing.

Keywords?

First, no keyed alphabet for each of the three cipher systems.

Then: Kryptos (obvious), Hydra (superscript in K3), L.Hydra (superscript plus extra L on Vigenere side), Medusa (in interviews and in Cyrillic projector).  This is four tries for bifid and playfair but I’ll probably only try kryptos-hydra, kryptos-medusa, hydra-medusa for foursquare.  There’s a lot of possible keywords to try and this list may change as things progress.  If anyone has a keyword that they are convinced should be considered (in this limited context) that is more than 5-6 letters with no letter repeats then feel free to put it out there.

So…

Playfair 5 times, bifid 5 times and foursquare 4 times…  14 digraphic decryptions for each transposed text, not terrible.  10 experimental texts would require 140 different “runs”.  It’ll be interesting to see the time commitment needed.

That’s the plan.  Of any “piece” of my efforts this is the one I would most like feedback on, besides, “that’s not how it’s going to work”.  Let’s allow the my assumptions, temporarily, and do the best to set it up so that if it’s going to work this way then it’s given the best chance of succeeding.  Then if it fails miserably we can all feel good about looking at other methods without a lingering doubt.