What if the file isn't necessarily what the client was looking for? (i.e. I upload a file called Terminator Movie, but it's actually Star Wars or just the first 30 minutes of the movie or even some kind of malware). Would that punishment just be reputation since the file could still be decrypted properly?
I guess this can only be solved by someone attesting to the validity of that particular decrypted file hash. It must be public knowledge / well-known. Very similar to how torrents work though, so it seems to be fine.