Encrypted Group Chat Protocols Diverge on Nostr
Developers contrast three competing architectures — Marmot, Concord, and Cordn — navigating the unresolved tensions between serverless scaling, metadata privacy, and relay indexing.
Encrypted group chat on nostr is being solved three different ways.
The proliferation of end-to-end encrypted messaging across public relays has created a divide between lightweight peer-to-peer designs and coordinator-assisted architectures.
Engineers analyzing the protocol landscape highlighted the fundamental design trade-offs currently dividing client implementations across the ecosystem:
Marmot (MLS for small high-stakes groups, no privileged server), Concord (Discord-style communities with shared-key streams and signed rosters, five established clients), and Cordn (MLS through a lightweight self-hostable coordinator that is blind to content, identities, and IPs, with nothing identifiable as Cordn messaging persisting on public relays).
The distinction touches the core philosophy of open protocols. Where Marmot enforces cryptographic security without relying on specialized infrastructure, Cordn isolates messaging traffic from public relay indexes through blind coordinator nodes, preventing observers from mapping social network graphs.
