Adventures in the Design of Anti-Surveillance Technology (Katzenpost)

This will be presented by Eva Infeld and Leif Ryge. We hope for an interactive discussion. In a world with state and corporate surveillance actors of immense power, building anonymity technology is an exercise in trade-offs, and few guarantees. But anonymity technology is badly needed. We introduce Katzenpost, a project that enables individuals and communities to build their own mixnets for anonymous communication. It has the eventual goal of resistance to attacks by large-scale passive and active adversaries, and to expected advancements in cryptanalysis such as attacks by cryptographically relevant quantum computers. We will explain our motivations, protocol design choices, and discuss the resulting protocol properties from several perspectives. This talk will also introduce the namenlos network, an instantiation of a mixnet using the Katzenpost software which may be used for experimentation today. Launched in 2022, namenlos consists of servers run by volunteers in several different countries. While we do not currently set security and privacy expectations, namenlos is the first hybrid post-quantum mixnet designed to resist large-scale adversaries built entirely with Free Software.