I proposed a construct which could be used for this application: called "amortizable hashcash". http://www.cypherspace.org/hashcash/amortizable.pdf The application I had in mind was also file sharing. (This was sometime in Mar 2000). I described this problem as the "disitrbuted document popularity estimation" problem. The other aspect of the problem is you have to distribute the popularity estimate and make it accessible, so I think you want it to be workably compact (you don't want to ship around 1 million hash collisions on the document hash). Amortizable hashcash addresses this problem. There is also some discussion of it here: http://archives.neohapsis.com/archives/crypto/2000-q1/0440.html Adam On Wed, Jul 31, 2002 at 04:25:30PM +0200, Eugen Leitl wrote:
It should use scarce resources (e.g. crunch) to generate a trust currency in each node, a kind of decentralized mint (nothing crunches quite a few million boxes on the Net).