The development of anonymous communication networks primarily focused on maintaining the privacy of users and initially disregarded performance to a large degree. As a consequence, networks such as Tor and Freenet suffer from a lack of performance based on suboptimal decision with regard to the chosen networking protocols. Prof. Roos will introduce some of the problems experienced by these systems. Afterwards, she will provide two solutions for both Tor and Freenet, of which one is a short-term solution that is easy to implement while the second solution entails a steep performance increase but requires fundamental design changes. In the context of Freenet, she and her team modified the peer selection algorithm to reduce the latency of content retrieval. They further showed that changes to the overlay addresses will result in significantly less overhead. For Tor, introducing a congestion control algorithm can reduce stall-outs and delays due to congestion but significant latency improvements require changing the transport layer protocol.
Stefanie Roos is a assistant professor for distributed systems at TU Delft. Her research focuses on privacy and security in distributed systems. In particular, she has designed anonymous, attack-resilient, and efficient routing protocols for P2P networks. Some of her results have been integrated in Freenet, a P2P-based censorship-resistant publication system. At the moment, she conducts research on realizing off-chain transactions to overcome the scalability and privacy issues of cryptocurrencies. Furthermore, she investigates congestion control algorithms for anonymity networks such as Tor.
Prior to joining TU Delft, Stefanie was a post-doctoral fellow at University of Waterloo, working with Ian Goldberg. She holds a doctorate from TU Dresden and was awarded the KuVS Promotionspreis 2017 honouring the best theses in networking and distributed systems in Germany for a her PhD thesis ‘Analyzing and Enhancing Routing Protocols for Friend-to-Friend Overlays’, supervised by Thorsten Strufe.