[MLS] New drafts from Rohan

[Rohan Mahy <[e-mail]>]

Hi Everyone,
>From my side I'll give a quick update on new and updated MLS drafts.

draft-ietf-mls-pq-ciphersuites has NOT been updated yet, but will be before
the meeting. We have special permission to submit this after the draft
deadline because it is the last in a chain of 4 other drafts it depends on.
Stay tuned.

draft-mahy-mls-sd-cwt-credential
<https://www.ietf.org/archive/id/draft-mahy-mls-sd-cwt-credential-01.html>
defines SD-JWT and SD-CWT credential types for MLS. I updated the document
to explain that these could just be otherwise pretty ordinary JWTs or CWTs
with key binding. Using the selective disclosure functionality isn't
mandatory.

Private External Messages (draft-mahy-mls-private-external
<https://www.ietf.org/archive/id/draft-mahy-mls-private-external-00.html>)
lets you HPKE encrypt an (ex: external proposal) PublicMessage to everyone
in the group so the DS can't read your LeafNode/Credential.

More efficient FramedContentTBS (draft-mahy-mls-new-framed-content-tbs
<https://www.ietf.org/archive/id/draft-mahy-mls-new-framed-content-tbs-00.html>)
is a super simple extension that uses the hash of the GroupContext in
FramedContentTBS instead of the whole GroupContext.

New content types (draft-mahy-mls-new-content-types
<https://www.ietf.org/archive/id/draft-mahy-mls-new-content-types-00.html>)
explores the idea of having several "application" ratchets split on new
content types that can have more aggressive deletion schedules for status
updates and completely ephemeral messages (ex: isTyping).

Including pending proposals in external commits (
draft-mahy-mls-ext-commit-pp
<https://www.ietf.org/archive/id/draft-mahy-mls-ext-commit-pp-00.html>) is
an extension that makes all otherwise pending proposals valid inside an
external commit, and discusses the security tradeoff.

Semiprivate message (
https://www.ietf.org/archive/id/draft-mahy-mls-semiprivatemessage-06.html)
has no changes, just a refresh.

Likewise, ratchet tree options (
https://www.ietf.org/archive/id/draft-mahy-mls-ratchet-tree-options-03.html
) has no changes.

Thanks,
-rohan