Re: Key updates

Dmitri Tikhonov <dtikhonov@litespeedtech.com> Tue, 07 August 2018 12:23 UTC

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Date: Tue, 7 Aug 2018 08:23:29 -0400
From: Dmitri Tikhonov <dtikhonov@litespeedtech.com>
To: Kazuho Oku <kazuhooku@gmail.com>
Cc: Martin Thomson <martin.thomson@gmail.com>, QUIC WG <quic@ietf.org>
Subject: Re: Key updates
Message-ID: <20180807122328.GA1645@ubuntu-dmitri>
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On Tue, Aug 07, 2018 at 04:39:38PM +0900, Kazuho Oku wrote:
> Reordered packets will not be dropped, assuming that an endpoint will
> not issue more than one key update within a short amount of time (a
> guarantee that is provided by the described design), that each
> endpoint will retain at most 2 keys for decryption. Nor there will be
> trial decryption.

This is my understanding as well.  The key phase bit is simply an
index into an array of keys of size 2 that each side uses as a ring
buffer.  A new key overwrites the old key and the current key becomes
the old key.

  - Dmitri.