I'm following this discussion with interest and am very curious what a "mapping" like this would reveal.
I can see wanting to disregard sources from after ~1438, particularly when they involve developments that seem to have been considered innovative at the time (like the Alberti Wheel). But I wonder how far before ~1404 it's worthwhile to look.
Judging from the diplomatic ciphers more or less contemporaneous with the VM which I've seen so far, the "state of the art" seems to have entailed providing multiple, interchangeable glyphs for each plaintext character; nulls; and code symbols for specific words and names. The favored strategy for increasing security was, I take it, to increase the number of different characters in the key. The result always seems to be a much larger character set than we see in the bulk of the VM.
If we turn to Meister's Anfänge, it seems as though the only relevant ciphers cited there that involve a *reduced* character set fell out of diplomatic use long before the VM, such as the ones substituting different quantities of crosses or dots for vowels. Of course there may be other, later examples I don't know about, which a "mapping" effort might helpfully turn up.
One *much* older cipher that involved a reduced character set was the Polybius Square, daring back to classical antiquity, with its fractioning of characters into pairs of coordinates. But Polybius' work was apparently only "rediscovered" during the Renaissance, so the Polybius Square may not have been known in Western Europe continuously since ancient times. I've seen Leonardo Bruni (ca. 1370-1444) characterized as "among the first in the West to read" Polybius --
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-- and Bruni was Chancellor of Florence, so if we'd expect any Italian diplomatic cipher of the era to have drawn inspiration from the Polybius Square, I guess it would be a Florentine one (even if Meister's descriptions of Florentine ciphers, at least, suggest they followed more or less the usual logic). Indeed, it's hard to imagine any serious cipher-designer of that time reading the tenth book of Polybius and *not* trying to take advantage of the idea somehow. So I'm not surprised to see Mark taking an interest specifically in Florentine diplomatic ciphers, though I don't know if it's for this reason or some other one.
In general, I can't help but think that the VM script doesn't seem to resemble the mainstream ciphers of its own era very closely, but that it might have built on some older model that was known only to a few (e.g., Polybius) or would have been considered obsolete (e.g., those dot-and-cross ciphers). So I hope we won't disregard sources from the fourteenth century and before as "out of scope."
I can see wanting to disregard sources from after ~1438, particularly when they involve developments that seem to have been considered innovative at the time (like the Alberti Wheel). But I wonder how far before ~1404 it's worthwhile to look.
Judging from the diplomatic ciphers more or less contemporaneous with the VM which I've seen so far, the "state of the art" seems to have entailed providing multiple, interchangeable glyphs for each plaintext character; nulls; and code symbols for specific words and names. The favored strategy for increasing security was, I take it, to increase the number of different characters in the key. The result always seems to be a much larger character set than we see in the bulk of the VM.
If we turn to Meister's Anfänge, it seems as though the only relevant ciphers cited there that involve a *reduced* character set fell out of diplomatic use long before the VM, such as the ones substituting different quantities of crosses or dots for vowels. Of course there may be other, later examples I don't know about, which a "mapping" effort might helpfully turn up.
One *much* older cipher that involved a reduced character set was the Polybius Square, daring back to classical antiquity, with its fractioning of characters into pairs of coordinates. But Polybius' work was apparently only "rediscovered" during the Renaissance, so the Polybius Square may not have been known in Western Europe continuously since ancient times. I've seen Leonardo Bruni (ca. 1370-1444) characterized as "among the first in the West to read" Polybius --
You are not allowed to view links. Register or Login to view.
-- and Bruni was Chancellor of Florence, so if we'd expect any Italian diplomatic cipher of the era to have drawn inspiration from the Polybius Square, I guess it would be a Florentine one (even if Meister's descriptions of Florentine ciphers, at least, suggest they followed more or less the usual logic). Indeed, it's hard to imagine any serious cipher-designer of that time reading the tenth book of Polybius and *not* trying to take advantage of the idea somehow. So I'm not surprised to see Mark taking an interest specifically in Florentine diplomatic ciphers, though I don't know if it's for this reason or some other one.
In general, I can't help but think that the VM script doesn't seem to resemble the mainstream ciphers of its own era very closely, but that it might have built on some older model that was known only to a few (e.g., Polybius) or would have been considered obsolete (e.g., those dot-and-cross ciphers). So I hope we won't disregard sources from the fourteenth century and before as "out of scope."
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