Engineering your own voynich

[mja0075]

Congratulations! How practical is it for reading if used as an actual cipher? Is it always simple to determine the boundaries between the positions?

By my count there are (including duplicates):
106 groups with 1 possible decoding 
    40 groups with 2 possible decodings 
    62 groups with 3 possible decodings
    13 groups with 4 possible decodings
    6 groups with 6 possible decodings
    6 groups with 9 possible decodings (anything starting with "mm")

Which means, more than half of the "words" in the cipher are not deterministic, and there are 6.98x10^59 different decodes with this key.

However, most of these obviously produce nonsense english, so in reality it's not too bad, but it is slow to try the different word combinations. There's also no spaces encoded.

Could you share some details of how you managed to crack it?

I had been using nablator's cipher as an example case to try and build faster segmentation that could quickly and reliably find keys that successfully decrypted with AZDecrypt. This never got anywhere with Byatan's though, so I had claude pull AZDecrypt's scoring and decryption logic into the loop.

So basically, instead of segmenting the text, and then trying to solve, redoing segmentation with decryption runs in between. 

Some other notes:

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Score stolen from AZDecrypt is:
ngram (sum of ngram log scores)* (entropy) ^ entropy_weight (1)
plus some negative scores around number of symbols and polyphones

6-grams were sufficient.

The code assumed the layout of the cipher matched nablator's 3 column idea.

Eventually saw "enigma" in the output:
"enigmahasanelectrovechaniaalrotorvechanism" 

Googling led to wikipedia, which provided source text.

And then it was just iterating over the key until the outputs matched.
With such an easily identifiable source text, it only took about 5 minutes to iterate over the key.

My code is a mess, I will try and post a cleaned version sometime soon.

Respect to nablator  

Agreed!