Spam is a major problem facing email today, and current solutions are ineffective. This paper presents our progress towards defining and implementing a payment-based email delivery system that solves the problem of spam. We present an extension to the email delivery protocol for specifying and collecting payments, explain its security requirements, and illustrate the use of the Lightweight Currency Protocol as an underlying currency system for payment-based email. We discuss the various ways payment requirements can be presented to the end user, and explain our prototyping efforts and how they fit into the larger picture of a peer-to-peer service market based on micro-payments.
David A. Turner, Ni Deng