(21-05-2025, 10:36 PM)Koen G Wrote: You are not allowed to view links. Register or Login to view.Just for clarity, I didn't mean hypothetical in a dismissive way. Plenty of ciphers are probably the only attestation of their exact method. But it's still interesting to note that, if it is a cipher, it swims against the tide.
In full and vehement agreement --
if it is a cipher, it is a cipher that was invented by someone looking at the problems frequency anaylsis posed for simple monoalphabetic ciphers and going off on a very different tangent than the early 15th century mainstream null & homophones class of approaches. Nick Pelling disputes that characterization of the motivation behind that class of (European) approaches (You are not allowed to view links.
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(21-05-2025, 10:36 PM)Koen G Wrote: You are not allowed to view links. Register or Login to view.But it's still interesting to note that, if it is a cipher, it swims against the tide.
... and all the solvers are swimming with the tide!
(22-05-2025, 01:05 AM)ReneZ Wrote: You are not allowed to view links. Register or Login to view.... and all the solvers are swimming with the tide!
Nowadays they rather sit in their jacuzzi and chat with their robot butler about the fish that live in its bubbling depths.
Book cipher (16th century attested, used by queen mary)
There is this encryption method where both parties have a copy of the same book.
The way you communicate is something like "pageno lineno wordno". encoding means looking through your copy of the book for the word you want to write.
Probably not what was used in the voynich, it works better after the invention of the printing press when people could more easily have exact copies of the same book. it is very easy with manual copying to get different linenumbers. Maybe with the bible that was already explicitly numbered.
I will elaborate on this in a presentation at this year's Voynich Day—I am finalizing a preprint on the subject—but homophonic substitution ciphers can get you a long way toward Voynich-like properties if the cipher's substitution options are verbose. The fundamental tradeoff is that there must be fewer plaintext letters per VMS token, on average, than the manuscript's appearance would otherwise suggest.
The homophonic substitution ciphers at use in early 15th-century Italy already show experimentation with offering both multiple substitution options per plaintext letter and elaborate "compound glyphs" that substitute for syllables / orthographic bigrams. To get even roughly VMS-like text, a cipher has to build out a more robust set of substitution options and include some procedural wrinkles, but the resulting cipher is not terribly alien in its overall construction. Consider this 1448 cipher from Meister's 1902 study of 15th-century Italian ciphers: You are not allowed to view links.
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Quote:Consider this 1448 cipher from Meister's 1902 study of 15th-century Italian ciphers
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