IETF Logo Mail Archive

Re: [TLS] Industry Concerns about TLS 1.3

mrex@sap.com (Martin Rex) Mon, 26 September 2016 07:57 UTC

Return-Path: <mrex@sap.com>
X-Original-To: tls@ietfa.amsl.com
Delivered-To: tls@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 1FC7C12B09D for <tls@ietfa.amsl.com>; Mon, 26 Sep 2016 00:57:37 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -6.922
X-Spam-Level:
X-Spam-Status: No, score=-6.922 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_PASS=-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 zSe1XAwrGUXK for <tls@ietfa.amsl.com>; Mon, 26 Sep 2016 00:57:34 -0700 (PDT)
Received: from smtpde02.smtp.sap-ag.de (smtpde02.smtp.sap-ag.de [155.56.68.140]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id B000512B00A for <tls@ietf.org>; Mon, 26 Sep 2016 00:57:34 -0700 (PDT)
Received: from mail06.wdf.sap.corp (mail06.sap.corp [194.39.131.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtpde02.smtp.sap-ag.de (Postfix) with ESMTPS id 3sjGXX2hmwz25XC; Mon, 26 Sep 2016 09:57:32 +0200 (CEST)
X-purgate-ID: 152705::1474876652-0000521C-CDB0ED34/0/0
X-purgate-size: 741
X-purgate: clean
X-purgate: This mail is considered clean (visit http://www.eleven.de for further information)
X-purgate-Ad: Categorized by eleven eXpurgate (R) http://www.eleven.de
X-purgate-type: clean
X-SAP-SPAM-Status: clean
Received: from ld9781.wdf.sap.corp (ld9781.wdf.sap.corp [10.21.82.193]) by mail06.wdf.sap.corp (Postfix) with ESMTP id 3sjGXW5MSpzkn3Q; Mon, 26 Sep 2016 09:57:31 +0200 (CEST)
Received: by ld9781.wdf.sap.corp (Postfix, from userid 10159) id B22E01A558; Mon, 26 Sep 2016 09:57:31 +0200 (CEST)
In-Reply-To: <CADGaDpEfypv+0mMQGsYGhGUJH28+hb7exGqyzJy90cQ87q8yJA@mail.gmail.com>
To: Thijs van Dijk <schnabbel@inurbanus.nl>
Date: Mon, 26 Sep 2016 09:57:31 +0200
X-Mailer: ELM [version 2.4ME+ PL125 (25)]
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Type: text/plain; charset="US-ASCII"
Message-Id: <20160926075731.B22E01A558@ld9781.wdf.sap.corp>
From: mrex@sap.com
Archived-At: <https://mailarchive.ietf.org/arch/msg/tls/BcXfhlYos6o3rYgsAFqiFiPPMtc>
Cc: "tls@ietf.org" <tls@ietf.org>
Subject: Re: [TLS] Industry Concerns about TLS 1.3
X-BeenThere: tls@ietf.org
X-Mailman-Version: 2.1.17
Precedence: list
Reply-To: mrex@sap.com
List-Id: "This is the mailing list for the Transport Layer Security working group of the IETF." <tls.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/tls>, <mailto:tls-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/tls/>
List-Post: <mailto:tls@ietf.org>
List-Help: <mailto:tls-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tls>, <mailto:tls-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 26 Sep 2016 07:57:37 -0000

Thijs van Dijk wrote:
> 
> Regular clients, no.
> But this would be a useful addition to debugging / scanning suites (e.g.
> Qualys), or browser extensions for the security conscious (e.g. CertPatrol).

With FREAK and LOGJAM attacks, there is a significant difference in
effort between servers using a static private (DH or temporary RSA) key
vs. truely ephemeral key.  But security checks of "vulnerability scanners"
do not seem to do any checks on whether the server is presenting the
same public key on multiple handshakes.

Generation of truely ephemeral DH keys for every full handshake is IMO
quite expensive for 2048+ bits DH.  The reason why I like Curve25519
is that generation of ephemeral keys is cheap.

-Martin

v2.23.0 | Report a Bug | By Email