Stopping outgoing spam

We analyze the problem of preventing outgoing spam. We show that some conventional techniques for limiting outgoing spam are likely to be ineffective. We show that while imposing per message costs would work, less annoying techniques also work. In particular, it is only necessary that the average cost to the spammer over the lifetime of an account exceed his profits, meaning that not every message need be challenged. We develop three techniques, one based on additional HIP challenges, one based on computational challenges, and one based on paid subscriptions. Each system is designed to impose minimal costs on legitimate users, while being too costly for spammers. We also show that maximizing complaint rates is a key factor, and suggest new standards to encourage high complaint rates. Categories and Subject Descriptors H.4.3 [Information Systems Applications]: Communications—Electronic Mail General Terms Security Keywords Junk email, spam

• Type: Conference
• Year: 2004
• Where: SIGECOM
• Authors: Joshua T. Goodman, Robert Rounthwaite
• Keywords: Complaint Rates, Conventional Techniques, Outgoing Spam, SIGECOM 2004