To get out the original data from a compressed file, you just need to know the algorithm used (and for almost all formats, the file tells you). To get out the

To get out the original data from a compressed file, you just need to know the algorithm used (and for almost all formats, the file tells you). To get out the original data from an LLM, you need to supply... the original data. Or at least, a big chunk of it. The actually copyrightable chunk of it, arguably, since what a LLM can generate on its own is only its most predictable, unoriginal, generic chunks. Things it's seen a thousand times. Which may turn out to be an uncomfortably high % of most creative works.