Unsolicited commercial electronic mail, commonly referred to as spam, hascontinued to wreak havoc with electronic communication. Such emailconsumes significant bandwidth, users' productivity, and disk space.Several solutions have been proposed to eliminate spam in the last fewyears. We broaden the definition of spam as any email unwanted by theintended recipient. We propose a novel scalable scheme that aims to addmonetary cost to senders of such unwanted mail while allowing legitimatemail to be exchanged at no cost to users and in the same manner astoday. Our scheme is entirely complementary to the large number ofreceiver-based filtering ideas in use today. We describe our scheme,describe how it can be integrated into the existing Internet emailinfrastructure, and discuss our prototype implementation. Our schemewill neither outlaw spam, nor make it obsolete; however it will addmonetary cost only to spammers thereby increasing the potential oflowering the frequency and amount of spam.
Zalachander Krishnamurthy has published in various conferences includingIMC, SIGCOMM, WWW, Infocom, Usenix, USITS, etc. He has co-authored aProposed Standard on adding a delta mechanism to HTTP/1.1. He hasco-written and edited a book on UNIX, and was series editor for 8volumes in the 'Trends in Software' series of books. With Jennifer Rexford, he co-authored 'Web Protocols and Practice:HTTP/1.1, Networking Protocols, Caching, and Traffic Measurement' (672pp, Addison-Wesley). Portuguese, Japanese, and Russian translations ofthe book are available. A special issue of the Wiley Journal 'Software, Practice and Experience'on Web Technologies guest edited by Bala appeared in Feb 2004. He is onthe editorial board of ACM TOIT and SIGCOMM CCR, and on the SteeringCommittee of the popular Internet Measurement Conference (SIGCOMM/Usenix)that he helped start three years ago. He has more than a dozen patents,published nearly sixty papers, and has given invited lectures in overthirty countries. Bala is homepageless but many of his papers can befound at