Re: [Cfrg] Security proofs v DH backdoors
John Mattsson <john.mattsson@ericsson.com> Thu, 27 October 2016 12:13 UTC
Return-Path: <john.mattsson@ericsson.com>
X-Original-To: cfrg@ietfa.amsl.com
Delivered-To: cfrg@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 5B8BC1294FC for <cfrg@ietfa.amsl.com>; Thu, 27 Oct 2016 05:13:08 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.221
X-Spam-Level:
X-Spam-Status: No, score=-4.221 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, 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 jkna_NSeNRbZ for <cfrg@ietfa.amsl.com>; Thu, 27 Oct 2016 05:13:04 -0700 (PDT)
Received: from sesbmg23.ericsson.net (sesbmg23.ericsson.net [193.180.251.37]) (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 463711293F9 for <cfrg@irtf.org>; Thu, 27 Oct 2016 05:13:03 -0700 (PDT)
X-AuditID: c1b4fb25-d35ee98000001e3e-43-5811ef4e9130
Received: from ESESSHC021.ericsson.se (Unknown_Domain [153.88.183.81]) by (Symantec Mail Security) with SMTP id 67.B7.07742.E4FE1185; Thu, 27 Oct 2016 14:13:02 +0200 (CEST)
Received: from ESESSMB307.ericsson.se ([169.254.7.87]) by ESESSHC021.ericsson.se ([153.88.183.81]) with mapi id 14.03.0319.002; Thu, 27 Oct 2016 14:13:00 +0200
From: John Mattsson <john.mattsson@ericsson.com>
To: Hanno Böck <hanno@hboeck.de>, Dan Brown <danibrown@blackberry.com>
Thread-Topic: [Cfrg] Security proofs v DH backdoors
Thread-Index: AdIuwSDNwRWUIafTQyeYSwlwLZEKKf//5BCAgAD8KoCAAVzI04AAmfyAgAAFUwCAADk+gA==
Date: Thu, 27 Oct 2016 12:12:59 +0000
Message-ID: <D437BA6E.542E3%john.mattsson@ericsson.com>
References: <20161025131014.5709905.2866.6563@blackberry.com> <20161025133016.GA9081@LK-Perkele-V2.elisa-laajakaista.fi> <1477456366629.49872@cs.auckland.ac.nz> <44595.1477524032@eng-mail01.juniper.net> <20161027103214.5709905.11728.6650@blackberry.com> <20161027125120.4d260334@pc1>
In-Reply-To: <20161027125120.4d260334@pc1>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
user-agent: Microsoft-MacOutlook/14.6.7.160722
x-originating-ip: [153.88.183.147]
Content-Type: text/plain; charset="utf-8"
Content-ID: <1E85F840A12EFB428F279105CECCAF34@ericsson.com>
Content-Transfer-Encoding: base64
MIME-Version: 1.0
X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrMIsWRmVeSWpSXmKPExsUyM2J7oK7fe8EIg0lzhCy6fxxksjjeu4TJ ouneVVaLl++eszqweMxqWMvucbHxAJPH14sv2D0mbzzMFsASxWWTkpqTWZZapG+XwJVx6NAL loJZYhVr/x9jb2C8INrFyMkhIWAicWb/I6YuRi4OIYH1jBKzb1xgg3AWM0o83zadHaSKTcBA Yu6eBjYQW0QgSmJF2zWwOLOAs8Tud9dZQGxhASOJzd9OskDUGEscPDofqj5MovPZbUYQm0VA VeJr7y2wGl4Bc4nLE94wQyxbyiRxZ/NXsASngJbEwrtHwJoZBcQkvp9awwSxTFzi1pP5TBBn C0gs2XOeGcIWlXj5+B8riC0qoCfx7PNzoOM4gOJKEtO2poGYzAKaEut36UNMsZb4+WwHI4St KDGl+yE7xDmCEidnPmGZwCg+C8myWQjds5B0z0LSPQtJ9wJG1lWMosWpxUm56UbGeqlFmcnF xfl5enmpJZsYgVF5cMtv1R2Ml984HmIU4GBU4uF9sE0gQog1say4MvcQowQHs5IIL9M7wQgh 3pTEyqrUovz4otKc1OJDjNIcLErivGYr74cLCaQnlqRmp6YWpBbBZJk4OKUaGAWSPH6tsA29 f2p+V+yEF9sWXrzxITIyzOPBn/VJZ4w7ZqdP69jnYvCx4nfSRfewG/tuO26xOK2o/DXB4kao 2asX3lOfVQVfu7ewVfK/asUsxT+zCnO5NX9f7nj24LRSgMHkgA+FTe+efF+6fG2g2on1XSbX O7eseCKrodtxy6RM/Yj3uTeJYS1KLMUZiYZazEXFiQC/gy0hxgIAAA==
Archived-At: <https://mailarchive.ietf.org/arch/msg/cfrg/hK2f3mXicwtcATuicL1zFpyuXp0>
Cc: CFRG <cfrg@irtf.org>, Peter Gutmann <pgut001@cs.auckland.ac.nz>
Subject: Re: [Cfrg] Security proofs v DH backdoors
X-BeenThere: cfrg@irtf.org
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: Crypto Forum Research Group <cfrg.irtf.org>
List-Unsubscribe: <https://www.irtf.org/mailman/options/cfrg>, <mailto:cfrg-request@irtf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/cfrg/>
List-Post: <mailto:cfrg@irtf.org>
List-Help: <mailto:cfrg-request@irtf.org?subject=help>
List-Subscribe: <https://www.irtf.org/mailman/listinfo/cfrg>, <mailto:cfrg-request@irtf.org?subject=subscribe>
X-List-Received-Date: Thu, 27 Oct 2016 12:13:08 -0000
Very much agree with you Hanno, the ONLY reason I can see to still support DH at all, is to have a fallback if someone comes up with a way of solving ECDLP faster that O(q^1/2). /John On 27/10/16 12:51, "Cfrg on behalf of Hanno Böck" <cfrg-bounces@irtf.org on behalf of hanno@hboeck.de> wrote: >On Thu, 27 Oct 2016 10:32:17 +0000 >Dan Brown <danibrown@blackberry.com> wrote: > >> For q=(p-1)/2, literally computing c^q for client public key is very >> slow. >> >> Why not use a faster alternative, such as checking Legendre symbol >> (c/p), use cofactor DH, or use even private keys? > >This line of debate and all the recently released papers show one very >concerning thing: We haven't learned how to use Diffie Hellman properly >- although it's an algorithm at the end of its life. > >I think when I read the logjam paper I became aware of how tricky of an >issue this is and how many things can go wrong with DH. It was also the >time when I concluded that the best is probably to just move beyond DH. > >Sure, there is probably a way to use DH in a way that reflects all >security concerns, is still reasonably performant etc. But why should >we have this discussion when we already know DH is on its way out? >Chrome already decided to disable it, others will follow. >Is there a good reason to keep DH around? One I'm aware of is that some >people think due to its larger size it's more resistant against >quantum computers. But I have heard multiple people familiar with QC >and pqcrypto that they don't buy that argument. > >I'm not arguing that ECC is simpler, but I'm arguing that we have >solved a lot of these issues facing DH already in a better way for ECC: >By simply not using random parameters which whoever decides, but by >using one or two good curves that have all desired properties. We >probably could do the same for DH, but we don't have to if DH is >deprecated anyway. > >-- >Hanno Böck >https://hboeck.de/ > >mail/jabber: hanno@hboeck.de >GPG: FE73757FA60E4E21B937579FA5880072BBB51E42
- [Cfrg] Security proofs v DH backdoors Dan Brown
- Re: [Cfrg] Security proofs v DH backdoors Ilari Liusvaara
- Re: [Cfrg] Security proofs v DH backdoors Hanno Böck
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Mark D. Baushke
- Re: [Cfrg] Security proofs v DH backdoors Dan Brown
- Re: [Cfrg] Security proofs v DH backdoors Hanno Böck
- Re: [Cfrg] Security proofs v DH backdoors Daniel Bleichenbacher
- Re: [Cfrg] Security proofs v DH backdoors John Mattsson
- Re: [Cfrg] Security proofs v DH backdoors Dan Brown
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Hanno Böck
- Re: [Cfrg] Security proofs v DH backdoors Michael Scott
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Hanno Böck
- Re: [Cfrg] Security proofs v DH backdoors Ilari Liusvaara
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Ilari Liusvaara
- Re: [Cfrg] Security proofs v DH backdoors Ilari Liusvaara
- Re: [Cfrg] Security proofs v DH backdoors Salz, Rich
- Re: [Cfrg] Security proofs v DH backdoors Michael Scott
- Re: [Cfrg] Security proofs v DH backdoors Tony Arcieri
- Re: [Cfrg] Security proofs v DH backdoors Hanno Böck
- Re: [Cfrg] Security proofs v DH backdoors Tony Arcieri
- Re: [Cfrg] Security proofs v DH backdoors David Adrian
- Re: [Cfrg] Security proofs v DH backdoors Watson Ladd
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Antonio Sanso
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Hanno Böck
- Re: [Cfrg] Security proofs v DH backdoors Tony Arcieri
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Tony Arcieri
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Watson Ladd
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Paterson, Kenny
- Re: [Cfrg] Security proofs v DH backdoors Paterson, Kenny