token revocation

[gwendalsimon]

It can happen that the content distributor would like to revoke a token. It is an offline action, which can impact the ongoing sessions.

If the full token is revoked, then it should mean closure of the WebTransport or MoQ connection. This can happen when the content distributor has identified the end-user as a leak.

If only some MoQT actions are revoked, then the related actions should be stopped: for example the Relay should stop the subscription to a track whose grant has been revoked. The use cases are less clear, but, I can think of a countermeasure where an identified leak can no longer get the top video profile but can still access a subset of degraded tracks.

[alficles]

Check to see if the moqt-reval claim helps: https://github.com/wilaw/CAT-4-MOQT/blob/main/draft-law-moq-cat4moqt.md#moqt-reval-claim

The idea here is that relays will keep the token associated with the stream and simply schedule re-evaluation at a future time. When you get a revocation, you add it to the bad list and then the next time you reval the token, it will fail and you'll terminate the stream.