I've been recently working at the direct-mail place putting rubber bands around mass mailings of junk mail (ah, the wonders of being a poor soon-to-be college student), which got me thinking about electronic junk mail and how such a thing can be avoided. In rl, you can go to the store, buy a product with cash, and you're not put on their mailing list. Buying via mail order, using check/credit-card, etc., requires that they get your address so they can put you on their mailing list, compile statistics about who you are, etc., as we all know. Now, over the net, suppose I wanted to buy an email product. I'd pay for it with digital cash, communicating with the vendor through the anonymous remailers. Now I see a problem in how the vendor will deliver the product. Obviously I can give the vendor my email address encrypted with the remailer's public keys, so the vendor still doesn't know who I am. But the vendor can still keep a database of address-blocks and which address blocks go with which purchases. Then the vendor can compile her mailing list of address blocks, and even *sell* this list to others, with product purchase history. Even though the junk-mailers don't know who I am, they can still flood my box with email. I thought of two possible solutions. The first solution I thought of requires a great deal of bandwidth. The vendor could simply post publicly (to usenet or something) the product I wanted, encrypted with my public key. (Rather, a public key I created just for this venture with a psuedonym so that none could see that it was I who was buying from the vendor.) The bandwidth for this thing would be incredible. The second solution I thought of seems like it would work. When I create the return-address block, it can be given some sort of ID-code (again, like with my other idea posted, similar to the ID-code on peices of Digicash in Chaum's scheme) so when the vendor delivers the product, she sends to encrypted block to the remailer, and the remailer forwards the product to me, and stores the ID-code in its database (doing the proper one-way transformation for untraceability) so that further attempts to use the exact same address-block will be noticed and not delivered. I also thought of creating a digicash like entity, a currency to pay for remailer transactions, so that sending junk mail through a remailer would be prohibitively expensive. It will probably happen anyway once we near the goal of full crypto-anarchy that most remailers will not operate without a fee, while the scheme I present above seems like it would work with both free remailers and those which charge for usage. (And a charge on a remailer which agrees with the market probably won't be high enough to stop a really rich junk mailer from spending the cash on junk mailings.) -- | Sameer Parekh-zane@genesis.MCS.COM-PFA related mail to pfa@genesis.MCS.COM | | Apprentice Philosopher, Writer, Physicist, Healer, Programmer, Lover, more | | "Symbiosis is Good" - Me_"Specialization is for Insects" - R. A. Heinlein_/ \_______________________/ \______________________________________________/