I agree. If charging for mail would eliminate spam, then I should not be getting the mailboxfull of physical junk mail I receive every morning. Postage benefits the MAIL CARRIER, not the recipient, and it is in the best interests of the mail carrier to carry MORE mail, not less. So, e-postage will almost certainly cause more spam, not less.
Hashcash is a more elegant and simple solution to UCE: most UCE is sent by small companies looking for a cheap way to get big exposure, they aren`t going to have the hardware to generate partial hash collisions for every address they want to mail, it would be prohibitively expensive for them to buy fast hardware to generate the collisions. Of course large companies who can afford to buy, or already have, mainframes will be able to send UCE, but most large companies are smart enough to realise that with the response rate gained from UCE, the reputation capital lost through sending it, and the valuable mainframe time used to generate the hashcash, it all adds up to a big shit sandwich. Adam Back: I haven`t read the hashcash paper/description for a while, can you give us some figures on how much processor time is required to generate hashcash for a 10,000 recipient spam, for n recipients? Sudden and very exciting idea: What if we could find a way to make the amount of hashcash required grow exponentially with the number of recipients? Of course the spammer could then find the optimum number of recipients and divide the list of addresses to be spammed into blocks of that size but that is a waste of sendmail time, also a waste of bandwidth and the overall time would probably still be prohibitively high. Datacomms Technologies data security Paul Bradley, Paul@fatmans.demon.co.uk Paul@crypto.uk.eu.org, Paul@cryptography.uk.eu.org Http://www.cryptography.home.ml.org/ Email for PGP public key, ID: FC76DA85 "Don`t forget to mount a scratch monkey"