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?

>>1
A quantum computer isn't that magic. The limit of 'superpositions' is just a couple of hundred. At most it is a finite parallel computer. It makes some calculations faster. Don't believe all that propaganda.