How Bad is Bad Enough?

Recently, I made my first tests to revive the Strokes theory of how the VM was enciphered and arrived at a quota of around 80% of the VM text (by volume, Currier A) which could be composed of Robert Firth’s 24 building blocks (or “syllables”). Now, is that a good or a bad result?

  • It can be considered bad inasfar as it’s “only” 80%. There are a number of degrees of freedom involved in the experiment, namely as regards transcription and block composition. Assuming that the VM text wasn’t written as a completely random string of symbols but governed by some kind of “grammar” which dictates possible word compositions, it’s not surprising that it’s possible to reconstruct a good chunk of this tome from some set of building blocks, especially if this building blocks are freely chosen. (And some of them consist only of a single letter, hey!) So one could argue that, if Firth’s blocks are any good, they should be able to cover more than 80% of the ciphertext.
  • On the other hand, one can consider the 80% surprisingly good. For example, the current set of 44 blocks allows for the representation of just two sets of characters forming the latin alphabet, one of uppercase and one of lowercase letters.*) This means that any special characters — arab digits, greek letters — aren’t covered from in this repertoire and drop through. Likewise Firths blocks didn’t include some gallows letters from the start, and thus are unable to compose words containing them.
    Let us add to this the high probabilities that

    • Firth’s block set isn’t completely correct, and
    • There are errors in the transcription system. With this I don’t mean a mistake in the transcription process, but an error in the transcription system, ie two different ciphertext letters are consistently considered the same (or vice versa), or two seperate letters are transcribed as one letter (or the other way around.) The ciphertext character set being unknown has notoriously been one of the obstacles of tackling the VM.**)

Any of these mistakes would naturally result in lower composition rates, and in the light of this, one could consider the 80% surprisingly good.

How to proceed from here?

As opposed to everyone else who seems bored under the Corona lockdown, I myself am actually quite busy. Nevertheless, there are two avenues of attack I’d like to write little pieces of software for:

  • One would be an interactive “Fiddler”. Basically, a piece of interactive software which lets you reassign plaintext letters to blocks and to change the blocks on the fly to see what effect this would have on a “decipherment.” With a little luck, and patient fiddling, one or the other readable word might come out of this, hinting at the “true” composition and assignment of the block…
  • Of course, there’s also the opportunity for a brute force attack. Empty diskspace is unused assets. The idea is to introduce random variations to the block set and see how these variations influence both the “composition rate” (ie the volume of text that can be synthesized with the blocks) and the number of blocks required for the composition.***) Letting the software run for a few hours and leaving the “better” results to survive (and discarding those which make the result “worse” might start an evolution towards a better optimized set of blocks.

Now all I need to do is find the time to hack the code.

*) Depending on whether some of the fancier renaissance additions like “j” and “w” or seperate letters for “u” and “v” should be considered.

**) The other being the underlying unknown plaintext language.

***) This might require a bit of explanation. I tried similar “evolition runs” in the past, but one problem was that they tend to “erode” the blocks used further and further until you’re left with a set of single-letter blocks. And this is only logical, because if you have a transcription which uses, say 44 different transcription letters, it will be possible to cover 100% of the transcription with 44 single-letter blocks, if each “block” contains exactly one letter of the set of transcription symbols. Thus there have to be two criteria whether one set of blocks is “better” or worse than the other in explaining the ciphertext:

  • The “better” set must cover more volume of the ciphertext, and
  • The “better” set must not use more blocks than the previous set. (Or, in other terms, the blocks used must be larger or of equal length.)

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