Private Hierarchical Governance for Encrypted Messaging
Armin Namavari, Barry Wang, Sanketh Menda, Ben Nassi, Nirvan Tyagi, James Grimmelmann
IEEE Symposium on Security and Privacy 2024 · Day 2 · Continental Ballroom 6
End-to-end encrypted (E2EE) messaging has become a cornerstone of digital privacy, deployed to billions of users across platforms like WhatsApp. This technology ensures that message content remains confidential, accessible only to the communicating endpoints, even in the event of a service provider compromise by hackers or malicious insiders. While this represents a significant victory for user privacy against external threats, it introduces a complex challenge for mitigating online abuse, such as misinformation, spam, and harassment, which does not require server compromise. The very strength of E2EE—its opacity to the service provider—makes traditional content-based moderation impossible.
AI review
This research introduces a novel, privacy-preserving framework for community-driven moderation within E2EE messaging by extending MLS. It successfully enables nuanced, context-specific policy enforcement while keeping governance state private from the platform, addressing a critical and complex challenge in online safety. The proof-of-concept demonstrates practical feasibility and scalability, offering a viable alternative to controversial client-side scanning.