Mark Knowles wrote:So do you disagree with John Friedman in the article Michelle cites?
Most of the article is about John de Foxton and Bacon. Friedman only devotes a couple of paragraphs to Fontana.
I agree with his basic description of Fontana's cipher system for vowels and some of the consonants (like other writers, Friedman doesn't fully describe all the mnemonics Fontana employed for the complete alphabet, but he gives the gist of it).
I also agree that the diagrams in Secretum are mostly mechanisms for shift-substitution ciphers (which is not the same as the mnemonic system used to actually write the book).
I would further agree that Fontana probably had more interest in developing his cipher system than in actual concealment.