Re: [MLS] Question regarding ClientInitKey message format

Benjamin Beurdouche <benjamin.beurdouche@inria.fr> Wed, 02 October 2019 16:11 UTC

Return-Path: <benjamin.beurdouche@inria.fr>
X-Original-To: mls@ietfa.amsl.com
Delivered-To: mls@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 6F45B120088 for <mls@ietfa.amsl.com>; Wed, 2 Oct 2019 09:11:37 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -6.899
X-Spam-Level:
X-Spam-Status: No, score=-6.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id nJ26Yt-c9NpL for <mls@ietfa.amsl.com>; Wed, 2 Oct 2019 09:11:35 -0700 (PDT)
Received: from mail2-relais-roc.national.inria.fr (mail2-relais-roc.national.inria.fr [192.134.164.83]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 071E012004F for <mls@ietf.org>; Wed, 2 Oct 2019 09:11:34 -0700 (PDT)
X-IronPort-AV: E=Sophos;i="5.67,249,1566856800"; d="scan'208,217";a="404432872"
Received: from 37-164-6-103.coucou-networks.fr (HELO [172.20.10.9]) ([37.164.6.103]) by mail2-relais-roc.national.inria.fr with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 Oct 2019 18:11:26 +0200
From: Benjamin Beurdouche <benjamin.beurdouche@inria.fr>
Message-Id: <2B3F98CF-26F7-4CF1-9CA3-002D2B0613F9@inria.fr>
Content-Type: multipart/alternative; boundary="Apple-Mail=_DBD6F4D2-8FE8-4F26-8862-766F922D9DC9"
Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.11\))
Date: Wed, 2 Oct 2019 17:11:24 +0100
In-Reply-To: <CAPEKH5ZhcAgUP-mNU=E1+C0z4sPRLYDX=woKdCpFd-eb-LkE-g@mail.gmail.com>
Cc: ML Messaging Layer Security <mls@ietf.org>
To: Pascal Junod <cryptopathe@gmail.com>
References: <CAPEKH5ZhcAgUP-mNU=E1+C0z4sPRLYDX=woKdCpFd-eb-LkE-g@mail.gmail.com>
X-Mailer: Apple Mail (2.3445.104.11)
Archived-At: <https://mailarchive.ietf.org/arch/msg/mls/jzVkkpzAccbLAMp_jI6KeEa2sBY>
Subject: Re: [MLS] Question regarding ClientInitKey message format
X-BeenThere: mls@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Messaging Layer Security <mls.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/mls>, <mailto:mls-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/mls/>
List-Post: <mailto:mls@ietf.org>
List-Help: <mailto:mls-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/mls>, <mailto:mls-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 02 Oct 2019 16:11:37 -0000

Hi Pascal,

If you look at the latest version of the draft (master) which is available on Github [0]
we moved away from having multiple cipher suites advertized in the ClientInitKey
to have only one ciphersuite [1], hence solving that issue at the same time… :)

Let me/us know if you have any questions…

Best,
Benjamin

[0] https://github.com/mlswg/mls-protocol/blob/master/draft-ietf-mls-protocol.md
[1] https://github.com/mlswg/mls-protocol/pull/204/files


> On Oct 1, 2019, at 4:30 PM, Pascal Junod <cryptopathe@gmail.com>; wrote:
> 
> Hello, 
> 
> I am new to that list, so please accept my apologies in advance for any wrong doings with respect to the list etiquette ! 
> 
> I am currently reading draft-07 (Aug. 13, 2019) and something is not clear to me with respect to the ClientInitKey format defined in section 7. The array of ciphersuites cipher_suites is expected to have a length of 0 to 255 ciphersuites, while the array of public keys init_keys is expected to have between one and 65535 public keys. At the same time, an above paragraph says that the init_array MUST have the same length as the cipher_suites array. Shouldn't both of them having a length <1,255> ? Or what did I misunderstand?
> 
> Best, 
> 
> Pascal
> _______________________________________________
> MLS mailing list
> MLS@ietf.org
> https://www.ietf.org/mailman/listinfo/mls