VMs: "Running code" -- I hope not...

[Elmar Vogt <elvogt@xxxxxxxxxxx>]

Hi all,

This afternoon I fiddled around a little with the idea of a "running code".

Essentially, I modelled a slightly alterated Alberti code wheel -- To encode 
text, you've got a pointer on the rotable inner disk, which you put beneath 
the current letter. Then you write down the character of the inner disk 
beneath the next letter from your source text, and subsequently move the 
pointer to this position, etc.

The results are funny. Your encoded text is a list of relative positions in 
your source, "jump forward 5 letters", "jump back 19", etc. (IIUC, you could 
describe this "relative coding" also as a polyalphabetic autokey coding) 
These jumps appear to have completely random distributions (well, what'd you 
expect?), and you get a binomial distribution for letter frequency in the 
coded text, ie whatever underlying structure you had is completely erased. 
(Not to mention making things even more difficult by employing a scrambled, 
rather than a sorted alphabet on the Alberti wheel.)

_If_ our author used this scheme, then "I've got a bad feeling about this," 
and I guess the text would be undecodable. Actually, I'm quite surprised 
nobody seems to have had this idea in period, while it's only a small step 
from the code wheel. (And to imagine that the bastard who encoded the VM 
perhaps just misunderstood the instructions...)

But the good thing about it is that it doesn't look like this running code 
was the scheme employed with the VM. VM text looks far too orderly and 
highly repetitive, and letter frequency distribution doesn't seem to fit either.

I'll keep you informed if I gain any new insight. Perhaps I can come up with 
an easy method to test a running matrix...

	Elmar

--
Elmar Vogt / Königswarterstr. 18 / 90762 Fürth / GERMANY
elvogt@xxxxxxxxxxx / Tel.: (++49/0)911 - 31 52 58
Agilmar von Sevelingen: VIS VISCERIS NON FERRE FERTUR (T.Doom)

"Patriotism is the virtue of the vicious." (Oscar Wilde, attrib.)

"I come from a country where being liberal is a virtue, and patriots are
viewed warily. YMMV."



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