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Re: VMs: Playfair cipher and triplets
At 20:25 19/01/2004 -0800, Jim Gillogly wrote:
The statistics aren't anything like a polyalphabetic or digraphic
cipher... at least not using the things that look like letters to
be the unit of the cipher.
I've tried out several hundred types of the kind of pairings/groupings one
might expect for a verbose cipher, and have yet to see any resulting stats
even remotely like those of a progressive-key polyalphabetic or a
Porta-style digraphic cipher at any level - in fact, there's structure
almost everywhere you look. :-o
BTW: from Alberti's codewheel-change every few words, I infer that the "you
need roughly 30 letters to break a monoalphabetic cipher" rule must have
been reasonably well-known circa 1470: and if you accept (from the
historical evidence) that this is the VMs' rough date of production, the
only reasonable inference is that the VMs (if some kind of cipher) must
involve some kind of cipher change every few words.
The only problem here is that this is what Steve Ekwall has been saying all
Cheers, .....Nick Pelling.....
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