Pudding: Private User Discovery in Anonymity Networks
Ceren Kocaogullar, Daniel Hugenroth, Martin Kleppmann, Alastair R. Beresford
IEEE Symposium on Security and Privacy 2024 · Day 3 · Continental Ballroom 4
In the evolving landscape of digital communication, **end-to-end encryption** has become a widely adopted standard for securing message content. However, the talk "Pudding: Private User Discovery in Anonymity Networks" by Ceren Kocaogullar and her collaborators at the University of Cambridge highlights a critical, often overlooked aspect of privacy: **metadata privacy**. This form of privacy protects information about a message's context, such as who is communicating with whom, when, and where. While anonymity networks like Tor and Nym are designed to provide robust metadata privacy, they traditionally lack user-friendly mechanisms for user discovery, leaving users to exchange complex, unmemorable addresses.
AI review
This research presents Pudding, an elegant application-layer protocol for private user discovery within anonymity networks like Nym. By leveraging deterministic SERBs and DKIM-verified email addresses, it effectively bridges the critical usability gap in metadata-private communication while maintaining robust unlinkability and membership unobservability. This is a highly impactful solution for a long-standing problem.