Quantum reverse hashing

You give a quantum computer a hash and a file size and it generates a superposition of all possible files that match that hash. Then you can select all files with only ASCII or UTF-8 characters or all files with valid MPEG headers or whatever type you want. Wouldn't that be awesome?

How about universal reverse hashing. When you need some data, start a universe and make life in it, then wait for them to come up with the data for you.