So I think hashcash is an interesting idea with some technichal merit,
and I'd like to help hammer out the bugs. I'd be happy to write or help
write a hashcash test for Sieve, although there are some bugs to work
That said, if Adam is willing, perhaps we should hit up Paul for yet
another IMC mailing list.
Which ever is most productive way to go. It depends how much work is
involved in hammering out details of hashcash, which in turn depends
on how generic it is made.
If you want to play with software, and try something with sieve, take
the hashcash implementation at http://www.dcs.ex.ac.uk/~aba/hashcash/
It includes an (inefficient) double spend database, collision
generator, and collision checker as a command line util complete with
useful exit codes.