A little while ago (in May) @Besao released an encrypted messaging protocol called Cordn (#1496327).

My understanding is that it allows you to do multiparty end-to-end encrypted communication but requires a coordinator. At the time of Besao's post, it sounded like Cordn was running a coordinator -- although they had published their code so anyone conceivably could do it.

And that seems to be what happened...but not as was expected:

Today, I saw Gzuuus post about an ephemeral coordinator on nostr:

Here is Cordn Ad-Hoc:

It looks like a temporary coordinator that vanished as soon as your browser tab is closed. It was created by a sandwich and looks pretty cool (to my totally naive eyes -- I do not know a thing about cryptography).

Cordn Ad-Hoc is a

Web-based MLS coordinator for ad-hoc Cordn groups. The app runs a ContextVM/Nostr coordinator in a browser tab, publishes its coordinator pubkey, and lets Cordn clients use that browser tab as the group coordination server.

Here's how sandwich describes what it does:

• Runs the Cordn coordinator protocol from a browser.
• Receives ContextVM MCP requests over Nostr relays.
• Stores MLS key packages, welcomes, join requests, and group messages locally.
• Supports streaming group-message subscriptions.
• Persists relay/runtime configuration in browser storage.
• Optionally encrypts and persists the coordinator identity behind a passphrase.
• Prevents multiple coordinators with the same pubkey from running at once.
• Exposes an operator debug log for raw Nostr events, decoded requests, responses, relay publish state, and instance heartbeats.