Server-Aided Continuous Group Key Agreement
Joël Alwen, Dominik Hartmann, Eike Kiltz, Marta Mularczyk · Proceedings of the 2022 ACM SIGSAC Conference on Computer and Communications Security · 2022
Continuous Group Key Agreement (CGKA) -- or Group Ratcheting -- lies at the heart of a new generation of scalable End-to-End secure (E2E) cryptographic multi-party applications. One of the most important (and first deployed) CGKAs is ITK which underpins the IETF's upcoming Messaging Layer Security E2E secure group messaging standard. To scale beyond the group sizes possible with earlier E2E protocols, a central focus of CGKA protocol design is to minimize bandwidth requirements (i.e. communication complexity).