Beyond Identity: Addressing Problems that Persist in an Electronic Mail System with Reliable Sender Identification

Many abuses of the Internet’s electronic mail system rely on its intrinsic lack of reliable sender identification, and many parties have proposed schemes to retro-fit sender identification into the system to combat such abuse. This paper considers what the spam problem and its countermeasures would be like under a theoretically ideal sender identification scheme, with some attention to the resource consumption the countermeasures entail—the economics of spam. Analysis suggests that no one single technique is likely to prove adequate, but a blended approach could be effective. Such an approach will create a need for integrated policy management facilities in future mail user agents.