Date: Fri, 19 Feb 1999 23:48:50 GMT
From: Adam Back <aba(_at_)dcs(_dot_)ex(_dot_)ac(_dot_)uk>
I have a proposal for another class of filtering criteria: filtering
on the basis of a token which consumes CPU time to produce as a method
to throttle systematic abuse.
I am requesting comments from this group because it seems the closest
match of IETF topic to "technical solutions to UBE". I am open to
comments as to how best to progress this technical solution.
We are not trying to solve the spam problem. That said, I like
hashcash. Adding a test for a hashcash value is trivial. But getting
Sieve out there is a large amount of work in itself.
The originator is required to send with email a costly to compute
token bound to that resource name. Example: Coyote emails Roadrunner,
he computes a hash collision on "roadrunner(_at_)birdseed(_dot_)org".
birdseed.org
runs a MTA filter rejecting mail without hashcash postage.
The problem with this is that it means the amount of computational power
that a mailing list costs is rather high.
--
Tim Showalter <tjs+(_at_)andrew(_dot_)cmu(_dot_)edu>