I appreciate the idea behind this, but seems difficult to scale. Different websites have different requirements (ie at least one symbol, low max number of characters etc) that the hashing algorithm you are using does not account for.
Also, for this kind of thing it would be good to provide the source code as well. I trust you, of course, for someone who really cares about the things you solve (ie no database), then being able to compile it yourself it's almost a requirement.