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VMs: What if Alberti wasn't so smart...?

Hi everyone,

Here's a question I've been pondering for a while: what if Leon Battista Alberti wasn't so smart?

AFAIK, the "standard" rendering of pre-polyalpha crypto history goes like this:-
(1) crypto guys make monoalphabetic ciphers
(2) crypto guys add nomenclators (extra shapes) for frequent words
(3) crypto guys add homomorphs (alternative shapes) for vowels
(4) crypto guys add extra symbols for (vowel, consonant) pairs
(5) 1466/7: Alberti invents the code-wheel
(6) 1470: Alberti writes about his code-wheel, but no-one reads about for years
(7) 1472: Alberti dies
(8) 1500-ish: Trithemius develops progressive key (cycling) polyalphabetic ciphers, etc

But... perhaps it's not quite that simple. First of all, (AIUI) Alberti never intended the code-wheel to be "clicked round" after every character (in the modern sense of polyalphabetic), but instead after every three or four words. Given that modern cryptanalysts reckon that a simple cipher needs something like 30 characters to be consistently breakable, that's actually bang on the money. :-) This means it's not quite the precursor to modern polyalpha you might think.

Secondly, looking again at the Tranchedino cipher ledger, I think there's another possibility. From ciphers like the one on page 3r (Cum Francisco Isulano de Tricio) which has three homomorphs for consonants (and four homomorphs for a/e/i/o/u), I wonder whether some encipherers in 1450 used only one row of such ciphers at a time (and perhaps used the extra homomorph for subsequent occurrences of vowels that appear twice within a cipher change)?

That is, I wonder whether Alberti, rather than *inventing* a kind of multi-cipher crypto practice, was in fact merely *technologising* an existing crypto practice? This would fit the "darker" modern view of Alberti (as discussed by Anthony Grafton in his recent book).

If there are some encrypted letters still extant in the Milanese archives (which we can link up to actual codes in the cipher ledger), then this could be explored further (and possibly falsified, if you subscribe to a Popperian view of science).

Alternatively, it might be an interesting idea to re-read Alberti's 1470 "Trattati In Cifra", AKA "Dello scrivere in cifra Roma", 27, 29, 41-42, 46-47, according to:
BTW: does anyone know of a facsimile copy or transcription of this?

Also: for a good-length excerpt from Anthony Grafton's recent book on Alberti:

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

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