P: A Protocol for Scalable Anonymous Communication

We present a protocol for anonymous communication over the Internet. Our protocol, called P 5 (Peer-to-Peer Personal Privacy Protocol) provides sender-, receiver-, and sender-receiver anonymity. P 5 is designed to be implemented over the current Internet protocols, and does not require any special infrastructure support. A novel feature of P is that it allows individual participants to trade-off degree of anonymity for communication efficiency, and hence can be used to scalably implement large anonymous groups. We present a description of P, an analysis of its anonymity and communication efficiency, and evaluate its performance using detailed packet-level simulations.