Reply To: Let’s talk about the Playfair cipher
This has been buried in the forums. I don’t think enough people have seen this gem of a Christmas present.
Thank you Madness for this post, it was truly a treat to read.
For anyone curious about how a Playfair can have a non-rectangular grid, the ciphertext Madness mentioned is 10B from my challenge (you can find this in the ‘Daily Cipher’ thread).
As for other ways of modifying the cipher:
– Rule 3 can be changed, the challenge I mentioned above uses triplets.
– Harry’s new favorite method: put playing cards in the grid!
– The grid can change during encryption, kind of autokey style.
I still have an extra plaintext for my challenge after 10B and might use a combination of the last two modifications to make a cipher even harder than the ‘non-rectangular’ playfair I used for 10B.