Re: VMs: For Nick Pelling

[Nick Pelling <incoming@xxxxxxxxxxxxxxxxx>]

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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