For perspective, Apple was scanning iphones for allegedly illegal files, based on their hashsum. However, I'm not sure the database of illegal hashsums is publicly available?

Presumably Google is doing the same thing, but in the cloud. However, does anybody have access to the database of copyrighted hashsums?

If society is going towards a world where we blanket filter based on the file's hashsum, then perhaps the government entity overseeing copyright should have a public database of these hashsum's? That way the public can know things are, or not, prior-art? Not only prior art, but potentially illegal in other ways.