Re: [TLS] STRAW POLL: Size of the Minimum FF DHE group

Bodo Moeller <bmoeller@acm.org> Wed, 05 November 2014 12:08 UTC

Return-Path: <bmoeller@acm.org>
X-Original-To: tls@ietfa.amsl.com
Delivered-To: tls@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id A5C7B1A8862 for <tls@ietfa.amsl.com>; Wed, 5 Nov 2014 04:08:16 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -0.262
X-Spam-Level:
X-Spam-Status: No, score=-0.262 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, FM_FORGED_GMAIL=0.622, HELO_EQ_DE=0.35, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_SOFTFAIL=0.665] autolearn=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 XEHKl2ERb81G for <tls@ietfa.amsl.com>; Wed, 5 Nov 2014 04:08:13 -0800 (PST)
Received: from mout.kundenserver.de (mout.kundenserver.de [212.227.17.13]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id BD6591A1A5F for <tls@ietf.org>; Wed, 5 Nov 2014 04:08:12 -0800 (PST)
Received: from mail-ob0-f176.google.com (mail-ob0-f176.google.com [209.85.214.176]) by mrelayeu.kundenserver.de (node=mreue102) with ESMTP (Nemesis) id 0MhDFZ-1XQJfX2QOf-00MMrm; Wed, 05 Nov 2014 13:08:10 +0100
Received: by mail-ob0-f176.google.com with SMTP id va2so420217obc.21 for <tls@ietf.org>; Wed, 05 Nov 2014 04:08:09 -0800 (PST)
MIME-Version: 1.0
X-Received: by 10.202.48.84 with SMTP id w81mr32549124oiw.30.1415189289135; Wed, 05 Nov 2014 04:08:09 -0800 (PST)
Received: by 10.60.32.42 with HTTP; Wed, 5 Nov 2014 04:08:09 -0800 (PST)
In-Reply-To: <83582340-5CEA-447E-9F83-5760E82D9A75@apple.com>
References: <9A043F3CF02CD34C8E74AC1594475C739B9DFCB9@uxcn10-5.UoA.auckland.ac.nz> <CADMpkc+Hu6gJa2c-7tJK-vhx5BaA+4gGbmpcr9MQskWEozttEQ@mail.gmail.com> <1498D16A-E16F-478A-B894-8C4F01BDB939@apple.com> <CADMpkcJEyHyuN1NjNNUag=+kBBPEEqb4Hp8dE+otMEF=EtWa8A@mail.gmail.com> <83582340-5CEA-447E-9F83-5760E82D9A75@apple.com>
Date: Wed, 05 Nov 2014 13:08:09 +0100
Message-ID: <CADMpkcL4DYVgrybru+-5QP-AZTXodhRyZXges8E1Q86sx+GJ8Q@mail.gmail.com>
From: Bodo Moeller <bmoeller@acm.org>
To: Michael Sweet <msweet@apple.com>
Content-Type: multipart/alternative; boundary="001a113cc582de783e05071b6e18"
X-Provags-ID: V02:K0:MGLNcVewvtk+gemkjvtQdOS22wuSTlJusGC41B3PaUT ePvqqjo7vgZVpmHT0r47sRRaRSZeufC8+vNWDxpFungXyyn6QO pbQMZC5f7yQyyA7LuboRBFcB9suQU3d80KVXuU8LuCnk3wmoj+ 09nhThP37o/xGrUobg6jzgQIaV/J3DPjOrAzX6+wlvlMQN7o6/ GkMGOosm4FQwn9bpYpDslJi07BvjvY68oFXXKDfRfpW4rvqWQJ Q32TVovDvF1D/8j9HUu2Yef8KdH4Cdx545VMUAZ7b8VsrrlNxQ 9W/VAIfEcf8MS86nlvCbued13AWWzMSp3ycvmuHOBO9TtKRH5F VRjw3JmUvY+40IpJGBc5dIJ1mPIWWvn09cKADZKPIw4UkVL2MQ uzCw80n24IAVdC9f4n2YNBZyhOJS622hmX/ZIja1DXKumjXGy5 jbFEs
X-UI-Out-Filterresults: notjunk:1;
Archived-At: http://mailarchive.ietf.org/arch/msg/tls/M1HUEjwV-oQMNXeuTlfxR2agv8E
Cc: "tls@ietf.org" <tls@ietf.org>
Subject: Re: [TLS] STRAW POLL: Size of the Minimum FF DHE group
X-BeenThere: tls@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
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: <http://www.ietf.org/mail-archive/web/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: Wed, 05 Nov 2014 12:08:16 -0000

Michael Sweet <msweet@apple.com>:

You can stretch the definition to say it's a non-integral power of 2
> (2^11.2479), but any number fits that definition.
>
> You could also say it is 19 x 2^7 or 1.1875 x 2^11.
>
> But there is no solution for "2432 = 2^n" where "n" is an integer.
>

Of course, but do you think it's a coincidence that all the
ECRYPT-recommended prime sizes are small (integral) multiples of a
(non-trivial) power of two? I think not.

(Not that there's anything wrong with that.)

Bodo