Core : A Peer-To-Peer Based Connectionless Onion Router

Onion Routing is today’s typical substrate for anonymous near-real-time communication. Via layered encryption, Onion Routers such as TOR [7] or Tarzan [8] build a static tunnel through a peer-to-peer relay network. All traffic exchanged between two end points uses one and the same tunnel, making the design susceptible to attacks based on pattern analysis. Recent publications [12] even extend this theoretical threat by showing the practical feasibility of a pattern analysis attack on the deployed TOR system. In contrast to today’s anonymous communication systems, Core routes each packet a different communication path and so is not susceptible to this class of attacks. Furthermore, inspired by IP-routing the connectionless approach reduces the complexity of the Onion Router. In this paper, we describe the design of our Connectionless Onion Router, evaluate its performance, and address the communication overhead. We present address virtualization to abstract from Internet addresses and to provide transparent application support. Thus, no application-level gateways or proxies are required to sanitize protocols from network level information. Acting as an IP-datagram service, our scheme provides a substrate for anonymous communication to a wide range of applications using TCP and UDP.