If you go to an ISP collects model, see how this changes the picture. At 6:57 AM -0700 5/14/03, Sunder wrote:
Yes, but how will you stop the spammer from double spending the same $0.25 micropayment on all of his 170,000 email addresses? Depending on whether you check that there is a payment attached or not, and also check it with the bank before delivering it, you'd have already wasted your bandwith and possibly have accepted a spam into your mail spool.
ISP receives mail header. As soon as the coin appears, it: (1) Check it against the in-memory Bloom filter of already seen coins. If it passes, goto collect. (2) Check it against the local database of already seen coins. (Because Bloom filters can give false positives.) If it is in the database, drop the mail and the connection. Result: no mail in the spool, and minimum bandwidth lost. (collect) Add the coin to the Bloom filter and to the database. Collect the money from the bank. If the bank says, "double spent", drop the connection and the mail as above. Note that this system will work well against spammers who blast out identical coins to a lot of addresses at an ISP. Now spammers can engage in a DOS attack against this system by using junk coins. It won't help them get the spam thru, and it will be detected when there is a TCP connection between their machine/open relay/etc. and the ISP machine. That will go a long way toward locating them in meat space, so fraud charges can be brought. Cheers - Bill ------------------------------------------------------------------------- Bill Frantz | Due process for all | Periwinkle -- Consulting (408)356-8506 | used to be the | 16345 Englewood Ave. frantz@pwpconsult.com | American way. | Los Gatos, CA 95032, USA --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to majordomo@metzdowd.com