Benjamin J. Kuipers, Alex X. Liu, Aashin Gautam, and Mohamed G. Gouda. 2005.
Zmail: Zero-sum free market control of spam.
4th International Workshop on Assurance in Distributed Systems and Networks (ASDN 2005). Columbus, Ohio, June 6, 2005.
Zmail is thus a "zero-sum" email protocol. Users who receive as much email as they send, on average, will neither pay nor profit from email, once they have set up initial balances with their ISPs to buffer the fluctuations. Spammers will incur costs that will moderate their behavior. Importantly, Zmail requires no definition of what is and is not spam, so spammers' efforts to evade such definitions become irrelevant. We describe methods within Zmail for supporting "free" goods such as volunteer mailing lists, and for limiting exploitations by email viruses and zombies.
Zmail is not a micro-payment scheme among end-users. It is an accounting relationship among "compliant ISPs", which reconcile payments to and from their users. Zmail can be implemented on top of the existing SMTP email protocol. We describe an incremental deployment strategy that can start with as few as two compliant ISPs and provides positive feedback for growth as Zmail spreads over the Internet.