Michael J. Freedman
New York Universtiy
Computer Science Department
715 Broadway, Room 715
New York, NY 10003
Title of Presentation: Building a Peer-to-Peer Anonymizing Network Layer
We examine the design considerations for building Tarzan, a
anonymizing network overlay. Because it provides IP service, Tarzan
is general-purpose and transparent to applications. Organized as a
decentralized peer-to-peer overlay, Tarzan is fault-tolerant, highly
scalable, and easy to manage.
Tarzan achieves its anonymity with layered encryption and multi-hop routing, much like a Chaumian mix. A message initiator chooses a path of peers through a restrictive topology in a way that adversaries cannot easily influence. Cover traffic prevents a global observer from drawing conclusions based on traffic analysis as to an initiator's identity.
Tarzan provides anonymity to either clients or servers, without requiring that both participate. In both cases, Tarzan uses a network address translator (NAT) to bridge between Tarzan hosts and oblivious Internet hosts, and it imposes minimal overhead over a corresponding non-anonymous overlay route. [More Information]