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Re: VMs: For Nick Pelling

Hi everyone,

At 23:16 06/11/2003 +0000, Jeff wrote:
I am now 95% sure I know how the VMS was done. I need to do a little further
analysis and I'll be 100% sure. I am sure it is Italian and not multiple
languages. I made a fundamental misjudgement in analysing my results! I
believe you are right about the origins, but don't hold your breath. If the
next couple of tests don't pan out then I'm back to the drawing board!

That's funny - while I'm now 95% sure of the author(s), the place, the context, the pre-history, the culture, the language, and even the contents of the VMs (sadly, I think you'll find that most of it isn't *hugely* interesting), I'm only 25% sure of *the why*, and only 15% sure of *the how*.

My sequence of inferences on the VMs' "how"-side:-
(1) because of the presence of "4" and "4o" in the cipherbet (and their appearance in Tristano Sforza's personal cipher of 1450, and Orfeo da Rycavo's 1455 cipher), I believe that the VMs is enciphered (probably after 1455, & probably by the same code-maker)
(2) because of the thinness of the VMs' vellum (and from Sergio Toresella's observations), I believe that it is a copy of other pre-existing manuscript(s)
(3) because of the matching top-left indent on f112r and f112v, I believe that the plaintext and ciphertext are matched line-for-line - that is, a line of plaintext codes as a line of ciphertext
(4) because of the curious entropy profiles (as well as the presence of "4o", etc), I believe that a letter of plaintext does *not* code as a letter of plaintext - that is, it is a verbose cipher
(5) because the individual letters are comfortably-spaced (and because of (3) and (4)), I believe that many of the plaintext letters have been removed (either by truncation or by contraction)
(6) because many of the letters in the VMs' alphabet closely resemble "single-stroke" tachygraphic shorthand, and because abbreviation is central to the only class of shorthand system (Radcliff's system) I can find evidence for in Europe after Tironian notes (and before Timothy Bright's "Characterie"), I believe that at least part of the systematic production of the VMs' ciphertext involved the use of shorthand.

If - as I believe - what we're looking at in the VMs is not just enciphered text but an enciphered shorthand, we have two (heavily overlapping) problems, both contributing to the apparent intractability of the whole problem:-
(a) identify the shorthand
(b) identify the cipher system

The problem with (a) is that all my best researches into the history of Quattrocento shorthand have revealed almost nothing useful - though it existed (and was in active use), because it was almost always taken down onto wax tablets (the stenographer's notepads of the day), it was transient... and appears to have been lost into the noise of the distant past.

The problem with (b) is that the cipher system was almost certainly designed to hide (or rather, to obfuscate) *not* the statistics of normal language, but the statistics of a (now unknown) shorthand. I think this is the observational step most crypto people may have overlooked with the VMs, probably seduced by the apparent (though deceptive) simplicity of its alphabet.

FWIW, this is just about as far as I'm comfortable with taking this line of reasoning ATM - everything else seems to rest on one's own interpretation of statistics... but beware! The VMs delights in making even the wisest statistical analysis of last night seem (in the cold light of morning) like so much drunken foolishness. I'm sure just about everyone here will attest to this. :-(

Cheers, .....Nick Pelling.....

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