Reusable hashcash for spam prevention

Adam Back adam at
Tue May 25 16:10:21 EDT 2004

FYI Richard amended the figures in the paper which makes things 10x
more favorable for hashcash in terms of being an ecomonic defense
against spammers.

Richard wrote on asrg:
| we're grateful (albeit a little embarrassed) for the consideration
| given to one of our figures by Ted Wobber (MS Research) who has
| pointed out a tenfold error in our sum involving an 0.0023% response
| rate
| we'll be revising our text accordingly -- since this will weaken our
| statements about the "economic argument" ... though it does _not_
| affect our analysis based on use of zombies.


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