Re: VMs: Possible optical device

[Nick Pelling <incoming@xxxxxxxxxxxxxxxxx>]

Hi Claus,

> just reading the "barrel" emails, I imagined an optical device made out of 
> 8 sides with engraved visual reading aids (keys).
> This device (made of glass or other translucent stuff like feldspath 
> (sp?)) will be put onto the "page" and you can cleary read the text with a 
> sort of adding the VMS text and the keys on the device.Each gallow will 
> tell the reader, which side of the device is to used.
> The "keys" will be engraved in the device (with acid or knife) and be only 
> visible when be seen on the bottom of the device.
> The opposite side of the keyy must be clear of course.

Nearly... but not quite. High-quality optics was to remain an open question 
for some time - for example, Leonardo da Vinci spent a lot of time working 
on it (unsuccessfully) late in in his life (post-1500). Even though there 
are (for example) a handful of sophisticated lenses made by the Vikings 
still in existence, it's clear that tricky optics wasn't really a 
mainstream technology pre-1600 (and probably pre-1700, depending on what 
you're thinking about).

If you're describing a movable key table, then the idea of a circular disk 
was floating in the ether at the time (probably based on general experience 
with astrological volvelles).

> As we have 8 gallows, the device can be horitzontal turned giving 8 
> possiblities.
> With such a device, the VMS can be read very easily, encryption should 
> take longer, but with practise, it can be done quite fast.
> Question: is such a device known from the time period of VMS's presumed 
> creation?

For the nearest equivalent, I guess you'd look to Leon Battista Alberti's 
cipher disk, described in his 1470 "Trattati di cifra" (though published 
much later). My suspicion is that the VMS is encoded using a similar system 
(amongst others), with roughly eight monoalphabetic ciphers driving a pair 
cipher back-end.

BTW, can anyone recommend a good book or website on Alberti? Most sites 
seem to have a paragraph on him and that's about it. I've read loads of 
books that discuss his Trattati superficially, but none that really get to 
grips with it.

> An additional advantage: you can show the book, but nobody can read it 
> with buying the device.

Perhaps (as I said before) the 9-rosette map page is a diagram of the 
encoding/decoding device, with the astrological section holding an encoded 
set of dials for the device. :-)

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


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