Let there be meaning

[oshfdk]

Actually, I do claim this, quite explicitly.

No, I wrote alone, as if all "stateful one to many cipher" should show these properties: of course they don't. Some do, some don't. Marco and René expressed their concerns as if there were no additional requirements.

I see, I misunderstood this comment. Anyway "stateful one to many character based additive cipher" is an umbrella term for almost any stream cipher. Any encoding that you can apply without knowing the whole source message in advance will usually conform to this very abstract definition. Even simple substitution with multiple tables selected via prefixes is one of those. I hope that using the most generic properties of these ciphers it will be possible to attempt breaking the Voynich encoding without assuming any scheme in particular.