Re: [Cfrg] Message Digest Algorithm Choice for CMS with Ed448
Russ Housley <housley@vigilsec.com> Wed, 16 November 2016 07:22 UTC
Return-Path: <housley@vigilsec.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 3522912954A for <cfrg@ietfa.amsl.com>; Tue, 15 Nov 2016 23:22:31 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -101.9
X-Spam-Level:
X-Spam-Status: No, score=-101.9 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, USER_IN_WHITELIST=-100] 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 qnJtDCFNBA_n for <cfrg@ietfa.amsl.com>; Tue, 15 Nov 2016 23:22:30 -0800 (PST)
Received: from mail.smeinc.net (mail.smeinc.net [209.135.209.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 12E931294D3 for <cfrg@irtf.org>; Tue, 15 Nov 2016 23:22:30 -0800 (PST)
Received: from localhost (localhost [127.0.0.1]) by mail.smeinc.net (Postfix) with ESMTP id 64C5B300AC5 for <cfrg@irtf.org>; Wed, 16 Nov 2016 02:12:12 -0500 (EST)
X-Virus-Scanned: amavisd-new at mail.smeinc.net
Received: from mail.smeinc.net ([127.0.0.1]) by localhost (mail.smeinc.net [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id DnM8muVkhAWC for <cfrg@irtf.org>; Wed, 16 Nov 2016 02:12:11 -0500 (EST)
Received: from dhcp-97b7.meeting.ietf.org (dhcp-97b7.meeting.ietf.org [31.133.151.183]) by mail.smeinc.net (Postfix) with ESMTPSA id C58393005AD for <cfrg@irtf.org>; Wed, 16 Nov 2016 02:12:10 -0500 (EST)
Content-Type: text/plain; charset="windows-1252"
Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\))
From: Russ Housley <housley@vigilsec.com>
In-Reply-To: <7DDD1353-96FC-4E70-8427-AA9C6F499232@vigilsec.com>
Date: Wed, 16 Nov 2016 02:22:24 -0500
Content-Transfer-Encoding: quoted-printable
Message-Id: <E07E9956-F0E9-4992-917C-8DA96CDE8252@vigilsec.com>
References: <7DDD1353-96FC-4E70-8427-AA9C6F499232@vigilsec.com>
To: IRTF CFRG <cfrg@irtf.org>
X-Mailer: Apple Mail (2.1878.6)
Archived-At: <https://mailarchive.ietf.org/arch/msg/cfrg/uPeX4x0pvM3cdiBwvIOyyZJfVvE>
Subject: Re: [Cfrg] Message Digest Algorithm Choice for CMS with Ed448
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: Wed, 16 Nov 2016 07:22:31 -0000
I’d like to summarize what I have heard. Either SHA3-512 or SHAKE256-512 provide the necessary protection. Both of these use Keccak, and both produce a 512-bit result. SHAKE256 is more efficient. I wrote a small test program, and it confirms that SHAKE256 is more efficient than SHA3-512. Looking at the NIST web pages, the algorithm identifier for SHA3-512 has been defined, but the only algorithm identifier for SHAKE256 has a 256-bit result. Quynh Dang says he can help with that. For the SHAKE256 algorithm identifier, I am thinking about something like this: hashAlg-SHAKE256 ALGORITHM ::= { OID id-TBD PARMS SHAKE256OutputSize } SHAKE256OutputSize ::= INTEGER -- Output size in bits Russ On Nov 12, 2016, at 10:55 PM, Russ Housley <housley@vigilsec.com> wrote: > The CURDLE WG is working on a document that specifies the > conventions for using EdDSA with CMS [RFC5652]. See > draft-ietf-curdle-cms-eddsa-signatures. > > The most common case involves these steps: > > 1. Compute a message digest on the content. > > 2. Create a message-digest attribute that include the > result from 1. > > 3. Gather all of the attributes that will be signed, which > includes the attribute from 2. > > 4. Digitally sign the set of attributes. > > For Ed448 (EdDSA with Curve448), step 4 uses SHAKE256. > > SHAKE256 uses SHA3-512 internally. > > What message digest algorithm should be used in step 1? > > It seems that SHA3-512 would be a good choice to avoid > having to implement more that one message digest algorithm > to generate the signature or validate it. > > Russ
- [Cfrg] Message Digest Algorithm Choice for CMS wi… Russ Housley
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Scott Fluhrer (sfluhrer)
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Ilari Liusvaara
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Derek Atkins
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Salz, Rich
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Taylor R Campbell
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Taylor R Campbell
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Jim Schaad
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Salz, Rich
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Taylor R Campbell
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Taylor R Campbell
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Russ Housley
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Ilari Liusvaara
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Derek Atkins
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Watson Ladd
- [Cfrg] Re: Message Digest Algorithm Choice for CM… Russ Housley
- Re: [Cfrg] Message Digest Algorithm Choice for CM… Ilari Liusvaara