> C=A^B is also pure noise

Is C really "pure noise" if you can get A back out of it?

It's like an encoding format or primitive encryption, where A is merely transformed into unrecognizable data, meaningful noise, which still retains the entirety of the information.

> Is C really "pure noise" if you can get A back out of it?

If you throw out B, then there's no possible way to get A out of C (short of blindly guessing what A is): that's one of the properties of a one-time pad.

But distributing both B and C is no different than distributing A in two parts, and I'd have a hard time imagining it would be treated any differently on a legal level.

No, C is really noise, fundamentally.

Imagine another copyrighted work D.

E=C^D, therefore C=D^E

As you see, the same noise can be used to recover a completely different work.

Since you can do this with any D, C is really noise and not related to any D or A.