The Feynman ciphers are a set of 3 ciphertexts apparently given to Richard Feynman at Los Alamos, only the first of which has been solved. This post will be a quick look at some of the statistics of the 3rd cipher. The Cipher itself is:
It is 231 characters in length (which has factors 3, 7 and 11), and has an I.C. of 0.0429, which means it is unlikely to be a transposition or substitution cipher. If we look at the monogram frequencies, we see all 26 letters appear, which means it can't be a cipher based on a 5 by 5 keysquare. This cipher actually looks statistically very close to the previous (second feynman cipher) which I have talked about previously (1, 2).
period 7 Vigenere 9
These are almost all Vigenere-type ciphers, I will try and run some cracking tools on them to see what happens.