[MLS] ChaChaX

Brendan McMillion <brendan@cloudflare.com> Mon, 10 August 2020 18:02 UTC

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From: Brendan McMillion <brendan@cloudflare.com>
Date: Mon, 10 Aug 2020 11:02:34 -0700
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To: Messaging Layer Security WG <mls@ietf.org>
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Subject: [MLS] ChaChaX
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Hello mls@

I wanted to quickly poll the list on a somewhat annoying issue. Currently,
every time we encrypt with our AEAD we use an unstructured nonce: sender
data encryption is properly random, while HPKE and message encryption use
the output of a KDF which is as good as random. Accordingly, we should be
using ChaChaX instead of ChaCha.

Does everyone else agree? Should I open these PRs?