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[TLS] Re: Working Group Last Call for Post-quantum Hybrid ECDHE-MLKEM Key Agreement for TLSv1.3

John Mattsson <john.mattsson@ericsson.com> Mon, 20 October 2025 14:37 UTC

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From: John Mattsson <john.mattsson@ericsson.com>
To: Sophie Schmieg <sschmieg@google.com>, Kris Kwiatkowski <kris=40amongbytes.com@dmarc.ietf.org>
Thread-Topic: [TLS] Re: Working Group Last Call for Post-quantum Hybrid ECDHE-MLKEM Key Agreement for TLSv1.3
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Date: Mon, 20 Oct 2025 14:37:49 +0000
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Subject: [TLS] Re: Working Group Last Call for Post-quantum Hybrid ECDHE-MLKEM Key Agreement for TLSv1.3
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Sophie Schmieg wrote:
>”with no opinion on the recommendation flag, other than a hope that we don't get distracted by it for too long.”
>”Well, technically my opinion is that X25519MLKEM768 should be recommended”


+1

(While I don’t have any personal use of SecP256r1MLKEM768 and SecP384r1MLKEM1024, I think they are strictly better than SecP256r1 and SecP384r1which are both Recommended=Y and SecP256r1 even being MTI. Let’s publish and argue about changes later…)

EKR wrote:
>It's purely about whether we think it's reasonable to implement.

This is the current meaning. RFC8447bis will change the meaning to:


“This only means that the associated mechanism is fit for the purpose for which it was defined.”

Cheers,
John

From: Sophie Schmieg <sschmieg@google.com>
Date: Tuesday, 14 October 2025 at 22:31
To: Kris Kwiatkowski <kris=40amongbytes.com@dmarc.ietf.org>
Cc: tls@ietf.org <tls@ietf.org>
Subject: [TLS] Re: Working Group Last Call for Post-quantum Hybrid ECDHE-MLKEM Key Agreement for TLSv1.3
I support publishing this draft, with no opinion on the recommendation flag, other than a hope that we don't get distracted by it for too long.

Well, technically my opinion is that X25519MLKEM768 should be recommended, but I also think that neither this flag nor the MTI flag have any meaning in the first place, due to the lack of an RFC police, so I am entirely indifferent on the value it is given.

On Tue, Oct 14, 2025 at 12:14 PM Kris Kwiatkowski <kris=40amongbytes.com@dmarc.ietf.org<mailto:40amongbytes.com@dmarc.ietf.org>> wrote:
Dear Dan,

Vulnerability scans show again and again that these

devices are normally out of date (and it's also well understood why)
This point is particulary interesting. Can you provide a reference to those vulnerability scans?
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--

Sophie Schmieg | Information Security Engineer | ISE Crypto | sschmieg@google.com<mailto:sschmieg@google.com>

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