Subject: [quicwg/base-drafts] 867af9: Rework Key Update

From: Martin Thomson <[email-masked]>
Date: Thu, 20 Dec 2018 17:26:29 -0800

Branch: refs/heads/simultaneous-update
  Home:   https://github.com/quicwg/base-drafts
  Commit: 867af94790a3e2cb696dadca9352d7bff537e37a
      https://github.com/quicwg/base-drafts/commit/867af94790a3e2cb696dadca9352d7bff537e37a
  Author: Martin Thomson <[email-masked]>
  Date:   2018-12-21 (Fri, 21 Dec 2018)

  Changed paths:
    M draft-ietf-quic-tls.md

  Log Message:
  -----------
  Rework Key Update

This section was pretty old and it had at least one bug, along with a
bunch of editorial lack of clarity.

Substantively, this does two things:

1. It specifies what label to use for the KDF when updating.  The
agreement at one time was that we would use a quic-specific label, but
that never really got captured properly.  This proposes "quic ku".

2. It specifies that acknowledgments of packets with a given key phase
are necessary before another update can be triggered.  As noted in
 #2214, simultaneous updates can result in a deadlock if updates happen
too quickly.  This has the nice effect of allowing update compliance to
be more rigorously tested.

Closes #2214.

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