Currier A and B

[julian]

So, as explained elsewhere, if the most common word in A is "daiin" and in B is "aiin", and we say they are the same plaintext word (seems reasonable), then the glyph "d" in Language A must be a null ... but this may be flawed reasoning :-)

...

Let's consider the cipher case next. Either two persons working together (or sequentially - like one is the follower of the other) or one person working sequentially would be unlikely to use two different ciphers (which, furthermore, use the same writing system) in a single volume. So the cipher algorithm is, most likely, the same.

...

Or, the cipher relies on some mechanism (e.g. a cipher disk) that was reset between the writing of A folios and B folios. So, the plaintext to VMS conversion is slightly "off" because the disk is slightly off. This might also happen with a grille ... if the grille was damaged or aligned badly by the time the B folios were written.