[nenaoki]

The pin would just be for coordination, not encryption.

[doomrobo]

Ah ok. How is the encryption key, if there is one, established then?

[nenaoki]

I think they just use the encryption and key exchange that WebRTC has cooked in https://datatracker.ietf.org/doc/html/rfc5764

[lxgr]

tl;dr: One peer generates a self-signed certificate and sends the fingerprint of that over the signalling channel; the other connects to it as a "client".

The resulting DTLS keying material is subsequently used for SRTP encryption (for media) and SCTP over DTLS (for the data channel, which is presumably what's being used here).

[avovsya]

You're right, thank you for answering!