Opportunistic Encryption Everywhere

Many of the core Internet protocols were designed for a less hostile network than the average packet finds itself in today. Many hosts are connecting over shared-key or open wireless networks where eavesdropping is trivial. On a larger scale, ISPs are experimenting with institutional sniffing where the clickstreams of the majority of users are observed and sold for their marketing value. Like the shift away from RSH and open mail relays, it’s our belief that all traffic should now be encrypted. As a practical matter this means opportunistic encryption, with all its complex trade-offs. In this paper, we explore these compromises and the design space of such a goal.