CS Seminar: Stefanie Roos - Mediating Tugs of War: Security-Performance Trade-offs in Embedding-based Routing Protocols

Speaker: Stefanie Roos (Waterloo)

Title:   Mediating Tugs of War: Security-Performance Trade-offs in Embedding-based Routing Protocols


In contrast to inherently compromisable client-server architectures, decentralized systems present a promising foundation for realizing anonymous and censorship-resistant communication. In addition to decentralization, relaying and delaying messages is essential to hide users' identities and hence prevent tracking, surveillance, and censorship. However, obfuscating information negatively impacts performance, which prevents large-scale adoption of these systems. In order to attract users, we have to develop privacy-enhancing technologies that are efficient and secure.

In this talk, I focus on the area of route-restricted Peer-to-Peer networks, i.e., networks with fixed connections that cannot be adapted to optimize the performance. Discovering routes efficiently and without revealing sensitive information about the communicating parties is hard due to the restricted connectivity.
Network embeddings, which assign coordinates that reflect the network structure, can facilitate route discovery in these networks. I derive security and performance requirements for routing algorithms considering two key applications, namely, message delivery and monetary transactions.
While previous approaches fail to meet these requirements, I present novel embedding-based routing protocols that balance security and performance, as validated by theoretical analysis in combination with large-scale simulation studies. I conclude by pointing out opportunities for deployment and future research.

Brief Bio:

Stefanie Roos is a post-doctoral fellow in the Cryptography, Security and Privacy group at University of Waterloo. 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.
Stefanie holds a doctorate from TU Dresden and an undergraduate degree in Mathematics from TU Darmstadt. She 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.




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