Re: [TLS] The future of external PSK in TLS 1.3

Peter Gutmann <pgut001@cs.auckland.ac.nz> Sat, 19 September 2020 11:48 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: John Mattsson <john.mattsson=40ericsson.com@dmarc.ietf.org>, "TLS@ietf.org" <TLS@ietf.org>
Thread-Topic: The future of external PSK in TLS 1.3
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Date: Sat, 19 Sep 2020 11:48:13 +0000
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Archived-At: <https://mailarchive.ietf.org/arch/msg/tls/bOCHh76qCCSyaX0K_kAbcugJoxY>
Subject: Re: [TLS] The future of external PSK in TLS 1.3
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John Mattsson <john.mattsson=40ericsson.com@dmarc.ietf.org> writes:

>Looking at the IANA TLS registry, I am surprised to see that psk_dhe_ke and
>especially psk_ke are both marked as RECOMMENDED. If used in the initial
>handshake, both modes have severe privacy problems,

PSK is used a fair bit in SCADA.  There are no privacy problems there.  So
just because there's a concern for one specific environment doesn't mean it
should be banned for any use.  In particular, I think if a specific industry
has a particular concern, they should profile it for use in that industry but
not require that everyone else change their behaviour.

Peter.