Addressing Spam E-Mail Using Hashcast

This paper investigates the problem of e-mail spam and identifies methods to efficiently minimize the volumes. It is argued that the usefulness of e-mail and its potential for future growth are jeopardized by the rising tide of unwanted e-mail, both SPAM and viruses. This threatens to wipe out the advantages and benefits of e-mail. An important flaw in current e-mail standards (most notably SMTP) is the lack of any technical requirement that ensures the reliable identification of the sender of messages. A message's domain of origin can easily be faked, or "spoofed". We focus on the Hashcash proof-of-work approach and investigate the feasibility of implementing a Hashcash-based solution. We conclude that a hybrid antispam system in conjunction with a legal and policy framework is best. However, this needs to be agreed on and implemented by the main industry players and technical bodies to be successful.