Cyber Security Seminar by Dr. Christiane Kuhn at the chair for IT security group at KIT - Provable Privacy for Onion Routing and Mix Networks

Abstract:

Onion routing and mix networks have been developed to enable anonymous communication even under surveillance. Those networks remove the relationship between the message and its corresponding sender by forwarding the message over multiple proxies that modify it at each hop. To guarantee that the applied modification sufficiently unlinks the sender and message, formal proof strategies for onion routing and mix networks emerged.

In this talk, I we will cover the field of provable privacy for onion routing and mix networks leading up to our recent findings (IEEE S&P 2020, AsiaCrypt 2021): Multiple "provably private" state-of-the-art protocols contain vulnerabilities that limit or even completely break their anonymity. Those vulnerabilities should not exist if privacy is proven correctly. We therefore analyse the used proof strategy to find its flaws and suggest an improved, effective one instead.

Short bio:

Christiane is a Postdoc at the chair for IT Security at KIT (Karlsruhe Institute of Technology). She is interested in understanding the underlying principles of anonymous communication networks and related privacy problems. In particular, she investigated privacy goal formalizations, proof strategies, as well as packet formats and performance bounds. She holds a PhD in Computer Science from KIT.