Let the Users Choose: Low Latency or Strong Anonymity? Investigating Mix Nodes with Paired Mixing Techniques

Sarah Abdelwahab Gaballah, Lamya Abdullah, Max Mühlhäuser, Karola Marky

Abstract: Current anonymous communication systems either provide strong anonymity with significant delay or low latency with unreliable anonymity. This division leads to smaller user bases and reduced anonymity as users choose systems based on their specific requirements. To address this issue, we propose an approach based on mix networks that employs two mixing techniques on mix nodes. Each technique offers distinct anonymity and latency guarantees—one for users valuing strong anonymity and another for those with specific latency constraints. We conducted an in-depth empirical study to evaluate the effectiveness of our proposal. The evaluation results demonstrate that our approach provides much more protection than the traditional method of using just one mixing technique on mix nodes. It offers enhanced anonymity for all users without impacting any user’s latency requirements. Furthermore, our findings indicate that our proposal eliminates the need for generating cover traffic to improve anonymity, achieving this improvement without introducing the bandwidth overhead associated with cover traffic.