[qhxkqcjf] Recording the hashes of web objects

A reputable web crawler creates and makes available an index of (URL,hash of content) tuples.  Maybe also add size.

Later, a user, wanting the content of a URL that is dead, looks up the URL in this index and gets the hash.  The user then offers a prize to anyone on the internet who can supply content that hashes to the given hash.  This can be verified automatically, though the details might be tricky.  Probably need reputable broker or escrow.