The Naibbe cipher

[magnesium]

Some thoughts on the Naibbe cipher.
The Naibbe cipher with 6 tables has 18 different ways to encrypt every plain text letter. 
If I have understood correctly how the randon way to choose the encryption works, in the case of simplfied spacing, it will split the size of the sample of every letter in 18 encrypted parts of equal size. 
For every plaintext letter: Are there 18 samples of equal size for the unigrams, prefixes and sufixes needed for the encription?

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The Naibbe cipher’ sability to disguise a given plaintext bigram in one of 36(6×6) ways through letter-by-lettert ables election is by far its greatest strength

The problem is again the random encryption, the samples of the 36 ways will have the same size, a weakiness.
A non random choice would be better, the preferences of the scribes in the use on some ways over another ones would split the 
size of the 36 ways in samples of different sizes, making them more difficult to decrypt

Thanks for your question! The cipher can generate 36 different ways of encrypting the same bigram, through 6 prefixes/letter and 6 suffixes/letter. But critically, not all prefixes and not all suffixes are equally likely to be chosen. The single commonest way to encrypt a given bigram occurs ~25/169 of the time, when the prefix and suffix are each encrypted using the primary table (aka 5/13 * 5/13). The 4 rarest ways to encrypt a given bigram each occur ~1/169 of the time, when the prefix and suffix are each encrypted using a tertiary table (aka 1/13 * 1/13). In short, the different ways of encrypting a given bigram can vary in their frequencies by a factor of 25, purely randomly—and that doesn't even include the possibility of a scribe developing a non-random preference for certain bigrams. In addition, the available prefix and suffix options all vary in their glyph lengths, so the 36 different bigrams can all vary in their glyph length, too.

To your general point about the re-spacing scheme: I'm incredibly open to people riffing on the general structure of the Naibbe cipher and coming up with their own re-spacing schemes, table approaches, etc. This is intended to be a useful reference model that delivers well-defined, reliable performance.