IETF Logo Mail Archive

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

Simon Josefsson <simon@josefsson.org> Mon, 20 October 2025 16:00 UTC

Return-Path: <simon@josefsson.org>
X-Original-To: tls@mail2.ietf.org
Delivered-To: tls@mail2.ietf.org
Received: from localhost (localhost [127.0.0.1]) by mail2.ietf.org (Postfix) with ESMTP id 26F417839351; Mon, 20 Oct 2025 09:00:58 -0700 (PDT)
X-Virus-Scanned: amavisd-new at ietf.org
X-Spam-Flag: NO
X-Spam-Score: -4.401
X-Spam-Level:
X-Spam-Status: No, score=-4.401 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: mail2.ietf.org (amavisd-new); dkim=neutral reason="invalid (unsupported algorithm ed25519-sha256)" header.d=josefsson.org header.b="Lm2tUWpc"; dkim=pass (2736-bit key) header.d=josefsson.org header.b="Y/IkUoqM"
Received: from mail2.ietf.org ([166.84.6.31]) by localhost (mail2.ietf.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id H-OpqdBrKO03; Mon, 20 Oct 2025 09:00:53 -0700 (PDT)
Received: from uggla.sjd.se (uggla.sjd.se [IPv6:2001:9b1:8633::107]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail2.ietf.org (Postfix) with ESMTPS id 014DB7837D96; Mon, 20 Oct 2025 08:58:28 -0700 (PDT)
DKIM-Signature: v=1; a=ed25519-sha256; q=dns/txt; c=relaxed/relaxed; d=josefsson.org; s=ed2303; h=Content-Type:MIME-Version:Message-ID:Date: References:In-Reply-To:Subject:Cc:To:From:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Ka/RFtX76EeETnvEAat4Tios41TfiaC4W3HrgEK0hFo=; t=1760975900; x=1762185500; b=Lm2tUWpcNFK+zphzrcspPKDglm+BmkJAooHBNvoUWTlIgo+7HrVp8qRjjfTwYE2Cc9yk3qdwbMv nONNi6dcSBA==;
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=josefsson.org; s=rsa2303; h=Content-Type:MIME-Version:Message-ID:Date: References:In-Reply-To:Subject:Cc:To:From:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Ka/RFtX76EeETnvEAat4Tios41TfiaC4W3HrgEK0hFo=; t=1760975900; x=1762185500; b=Y/IkUoqMX6519EjoodaXBGN8rKAaHwugXjigqDvNaRowISqNg2WMawP45Z6/iBgMLWq6+PJMJgQ hksLoJTtKj1qPrrAYQr78PpZ0L2o2RS+UII2HkSmLOVSjdmM3D3B+BMHShpFiRwxRAQaGgkWKY8N1 0kGO476aiYnHxSgskzW5dGf1PtNHvN0RSq7dh85M/lb2mMh6av0FX0slkbZnK1qmPtUXXFNejdgs6 LR4j4u/sBbTfg7wsEEsu7rjaKDfKU951+ykIJpzoTp+izZg5axg8h7fEYN1czcAuIlJ9iInwv5U1U 5sdiWufH3uE1r37PrBF5IOxOI/SsE6cDIeymoxQbsReTW8QDKBnTEbFSa60lsPn4EfAnHr19QeoyQ 2wUOo9taeaqbX18JHOOR7vaIPusacliYElqVvaC4EYznqEyRPppAt6vtjXEwQZV7MEQCExYpY;
Received: from [2001:9b1:41ac:ff00:2766:347f:b6a9:a22a] (port=44548 helo=kaka) by uggla.sjd.se with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from <simon@josefsson.org>) id 1vAsH3-003gY0-0G; Mon, 20 Oct 2025 15:58:17 +0000
From: Simon Josefsson <simon@josefsson.org>
To: Alicja Kario <hkario=40redhat.com@dmarc.ietf.org>
In-Reply-To: <a0d3380c-28aa-4669-99d8-0567355cf23b@redhat.com> (Alicja Kario's message of "Mon, 20 Oct 2025 17:36:27 +0200")
References: <GVXPR07MB9678ADD1D3268BB055751EA989F5A@GVXPR07MB9678.eurprd07.prod.outlook.com> <CABcZeBOH289QVSZomDfE8dUK5oB7kM0i_66s3S260WOjyTp4kw@mail.gmail.com> <871pmxip86.fsf@josefsson.org> <a0d3380c-28aa-4669-99d8-0567355cf23b@redhat.com>
OpenPGP: id=B1D2BD1375BECB784CF4F8C4D73CF638C53C06BE; url=https://josefsson.org/key-20190320.txt
X-Hashcash: 1:23:251020:hkario=40redhat.com@dmarc.ietf.org::27KWiBr9xSVBU9+x:1o77
X-Hashcash: 1:23:251020:tls@ietf.org::v/m9QPBFFb+emQ0S:8QJ6
X-Hashcash: 1:23:251020:simon=40josefsson.org@dmarc.ietf.org::y9hCfYRvuNQTze1h:KECN
X-Hashcash: 1:23:251020:john.mattsson=40ericsson.com@dmarc.ietf.org::ke4qhklFKwH5zbPm:Womw
X-Hashcash: 1:23:251020:kris=40amongbytes.com@dmarc.ietf.org::HDaU1m7trQUEifW3:0LRJn
Date: Mon, 20 Oct 2025 17:57:33 +0200
Message-ID: <877bwpd0r6.fsf@josefsson.org>
User-Agent: Gnus/5.13 (Gnus v5.13)
MIME-Version: 1.0
Content-Type: multipart/signed; boundary="=-=-="; micalg="pgp-sha256"; protocol="application/pgp-signature"
Message-ID-Hash: SLKFOBKJLH3HJOK5PA46RYFZMHQCVEQM
X-Message-ID-Hash: SLKFOBKJLH3HJOK5PA46RYFZMHQCVEQM
X-MailFrom: simon@josefsson.org
X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-tls.ietf.org-0; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header
CC: John Mattsson <john.mattsson=40ericsson.com@dmarc.ietf.org>, Kris Kwiatkowski <kris=40amongbytes.com@dmarc.ietf.org>, tls@ietf.org
X-Mailman-Version: 3.3.9rc6
Precedence: list
Subject: [TLS] Re: Working Group Last Call for Post-quantum Hybrid ECDHE-MLKEM Key Agreement for TLSv1.3
List-Id: "This is the mailing list for the Transport Layer Security working group of the IETF." <tls.ietf.org>
Archived-At: <https://mailarchive.ietf.org/arch/msg/tls/U1KfwAwbLnlLyyW_dJOkNfmvex8>
List-Archive: <https://mailarchive.ietf.org/arch/browse/tls>
List-Help: <mailto:tls-request@ietf.org?subject=help>
List-Owner: <mailto:tls-owner@ietf.org>
List-Post: <mailto:tls@ietf.org>
List-Subscribe: <mailto:tls-join@ietf.org>
List-Unsubscribe: <mailto:tls-leave@ietf.org>

Alicja Kario <hkario=40redhat.com@dmarc.ietf.org> writes:

> If that classical part was good enough to be MTI and stay as
> Recommended now, it should be good enough to be part of the hybrids
> too.

I disagree with that, if you imply that the P256 hybrid should be MTI.

So if old DSA was still MTI we have to make DSA + ML-DSA MTI too?

I think we should make decisions about P256+MLDSA based on today's
knowledge about P256 and MLDSA (and the combiner) rather than having
necessarily make decisions that use earlier decisions on P256 as a least
common denominator (i.e., MTI).

The decision about MTI P256 and MTI P256+MLDSA are really two orthogonal
decisions, made at different times, in different contexts.

/Simon

v2.35.0 | Report a Bug | By Email | System Status