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Re: [Ntp] Post NTS, Is shared key authentication interesting?

Daniel Franke <dfoxfranke@gmail.com> Mon, 25 May 2020 13:29 UTC

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From: Daniel Franke <dfoxfranke@gmail.com>
Date: Mon, 25 May 2020 09:29:09 -0400
Message-ID: <CAJm83bDMY0ZSU2u6WFm4FbYmcN39NqDhoTmb5pr4TYOTtve1Tw@mail.gmail.com>
To: Miroslav Lichvar <mlichvar@redhat.com>
Cc: NTP WG <ntp@ietf.org>
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Subject: Re: [Ntp] Post NTS, Is shared key authentication interesting?
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Yes, shared-key authentication is still interesting.

Putting the MAC in an extension field is clearly how NTPv4 should have done
things from the start, but I don't see any benefit in changing until the
legacy MAC field can be killed off entirely. So I would rather just pursue
this as part of NTPv5 than adopt a MAC EF draft for NTPv4.

I would like NTPv5's shared key authentication to be a little more closely
integrated with NTS. Either accomplish it by doing a PSK TLS handshake for
NTS-KE, or skip NTS-KE and have pre-shared S2C/C2S keys and a shorter
cookie giving just a key ID.

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