Messaging Layer Security: Towards a New Era of Secure Group Messaging
summary
A new group messaging protocol is proposed that replaces pairwise fanout with a TreeKEM binary trees state so group key updates run in O(log n) not O(n), demonstrated by a 100,000‑member example where a rotation is ~17 operations for 100k vs 100k and ~17 KB payload instead of 100 MB. It uses per‑member init keys for bootstrapping, four epoch operations (create add remove update), provides forward secrecy and post‑compromise recovery via frequent rotations, and leaves global ordering for delivery services unresolved.
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chapters (17)
- 0:00Introduction
- 8:11What do we do about groups
- 10:24Security tradeoff
- 11:46Security objectives
- 14:01Other objectives
- 15:17Open standard
- 16:02MLS
- 19:11TLS vs MLS
- 23:38Init Keys
- 24:34Binary Trees
- 31:54Operations
- 33:30Pairwise
- 36:49Metadata
- 39:12Liability
- 40:28Delivery Services
- 42:11Business Messaging
- 44:14Summary
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