Re: [DNSOP] SHA-1 chosen prefix collisions and DNSSEC

Tony Finch <dot@dotat.at> Fri, 10 January 2020 15:46 UTC

Return-Path: <dot@dotat.at>
X-Original-To: dnsop@ietfa.amsl.com
Delivered-To: dnsop@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id D700D1208E4 for <dnsop@ietfa.amsl.com>; Fri, 10 Jan 2020 07:46:43 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.198
X-Spam-Level:
X-Spam-Status: No, score=-4.198 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_NONE=0.001, URIBL_BLOCKED=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 sL2opYNjVsHa for <dnsop@ietfa.amsl.com>; Fri, 10 Jan 2020 07:46:40 -0800 (PST)
Received: from ppsw-43.csi.cam.ac.uk (ppsw-43.csi.cam.ac.uk [131.111.8.143]) (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 BDA5512006B for <dnsop@ietf.org>; Fri, 10 Jan 2020 07:46:40 -0800 (PST)
X-Cam-AntiVirus: no malware found
X-Cam-ScannerInfo: http://help.uis.cam.ac.uk/email-scanner-virus
Received: from grey.csi.cam.ac.uk ([131.111.57.57]:37060) by ppsw-43.csi.cam.ac.uk (ppsw.cam.ac.uk [131.111.8.139]:25) with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) id 1ipwUf-0019JI-od (Exim 4.92.3) for dnsop@ietf.org (return-path <dot@dotat.at>); Fri, 10 Jan 2020 15:46:37 +0000
Date: Fri, 10 Jan 2020 15:46:37 +0000
From: Tony Finch <dot@dotat.at>
To: dnsop@ietf.org
In-Reply-To: <76ABA29A-22AE-4F5E-BC15-05B1EB684473@dotat.at>
Message-ID: <alpine.DEB.2.20.2001101545360.19873@grey.csi.cam.ac.uk>
References: <76ABA29A-22AE-4F5E-BC15-05B1EB684473@dotat.at>
User-Agent: Alpine 2.20 (DEB 67 2015-01-07)
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Archived-At: <https://mailarchive.ietf.org/arch/msg/dnsop/mhrOWXrO4Indr8Y_sXPWPvdABy4>
Subject: Re: [DNSOP] SHA-1 chosen prefix collisions and DNSSEC
X-BeenThere: dnsop@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: IETF DNSOP WG mailing list <dnsop.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dnsop>, <mailto:dnsop-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/dnsop/>
List-Post: <mailto:dnsop@ietf.org>
List-Help: <mailto:dnsop-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dnsop>, <mailto:dnsop-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 10 Jan 2020 15:46:48 -0000

Tony Finch <dot@dotat.at> wrote:

> I have written a blog post with my understanding of the implications of
> the SHAmbles attack for DNSSEC.
>
> https://www.dns.cam.ac.uk/news/2020-01-09-sha-mbles.html

I've updated that with a correction about the SHA-1 input block size,
but that doesn't affect the overall conclusions.

Tony.
-- 
f.anthony.n.finch  <dot@dotat.at>  http://dotat.at/
Gibraltar Point to North Foreland: Northwesterly 4 or 5, backing southerly or
southwesterly 5 to 7, perhaps gale 8 later. Slight or moderate, smooth in
Thames estuary. Mainly fair. Good.