IETF Logo Mail Archive

Re: [Cfrg] A downside of deterministic DL signatures?

Tony Arcieri <bascule@gmail.com> Thu, 31 July 2014 21:09 UTC

Return-Path: <bascule@gmail.com>
X-Original-To: cfrg@ietfa.amsl.com
Delivered-To: cfrg@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id D39871A0179 for <cfrg@ietfa.amsl.com>; Thu, 31 Jul 2014 14:09:24 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.999
X-Spam-Level:
X-Spam-Status: No, score=-1.999 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, SPF_PASS=-0.001] autolearn=ham
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 4r4pXxV3cD8q for <cfrg@ietfa.amsl.com>; Thu, 31 Jul 2014 14:09:23 -0700 (PDT)
Received: from mail-vc0-x233.google.com (mail-vc0-x233.google.com [IPv6:2607:f8b0:400c:c03::233]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 312491A010A for <cfrg@irtf.org>; Thu, 31 Jul 2014 14:09:23 -0700 (PDT)
Received: by mail-vc0-f179.google.com with SMTP id hq11so5292754vcb.10 for <cfrg@irtf.org>; Thu, 31 Jul 2014 14:09:22 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; bh=rEf+EC+KOASciKTZUN11C4iVnYSpGdQzQAgU4OQ+JSU=; b=Xht+g8WhGPpp7Tbg6x/iJCKFzMaNeiBGRAXbd0ndVOACoRqKPatbjJQPCy/yqkRK44 bmWgFIQKrlPmA3/owujKISeiroDcdJoXXy+nZF3QxFOcf1v/7M3D9rl8arhjQrG2Fhdx yq7s9ZUW1z/hQdre8brgNmF4WU4dHdq9bVSLGwwQQG8g5DYRF/UJRRAp2z+s1iVLG6fF SB5rPZ9OkUYXTnyC2QdRznJgBlXlsrzO8MJ35XEqs0rJNOwde+9pxq6h6omwPpDHyuSv vl0DL+e0sFItdoab9AYmC1Eb+glsKWsuvj8+SHuX709nIgZBi/n2Q1Q5V/jgbrGOoCSX tPgw==
X-Received: by 10.52.0.209 with SMTP id 17mr1004489vdg.60.1406840962415; Thu, 31 Jul 2014 14:09:22 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.58.160.10 with HTTP; Thu, 31 Jul 2014 14:09:02 -0700 (PDT)
In-Reply-To: <53DA7B79.70709@fifthhorseman.net>
References: <20140729205846.6639765.71649.17355@certicom.com> <CAHOTMVJ4AirY+tRnVfwt1umgx=Q2xNwVTks6OoVNaV0gkKihOg@mail.gmail.com> <947D45A1-AF36-470B-8D50-7600FEF7FB30@shiftleft.org> <CAHOTMVJYr=S1fXXSYCHDJz2m6sn10uQ=ztXT7htW1m53qEZHog@mail.gmail.com> <53DA7B79.70709@fifthhorseman.net>
From: Tony Arcieri <bascule@gmail.com>
Date: Thu, 31 Jul 2014 14:09:02 -0700
Message-ID: <CAHOTMVKb8w2TeTpoZsMnJHtspp+xZrO-Ug7YpqUqW2Bc5itNmQ@mail.gmail.com>
To: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
Content-Type: multipart/alternative; boundary="047d7ba97002d2050904ff83aff0"
Archived-At: http://mailarchive.ietf.org/arch/msg/cfrg/R9l9F38ablzo6AIktb0TQeVveEI
Cc: Dan Brown <dbrown@certicom.com>, IRTF Crypto Forum Research Group <cfrg@irtf.org>
Subject: Re: [Cfrg] A downside of deterministic DL signatures?
X-BeenThere: cfrg@irtf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Crypto Forum Research Group <cfrg.irtf.org>
List-Unsubscribe: <http://www.irtf.org/mailman/options/cfrg>, <mailto:cfrg-request@irtf.org?subject=unsubscribe>
List-Archive: <http://www.irtf.org/mail-archive/web/cfrg/>
List-Post: <mailto:cfrg@irtf.org>
List-Help: <mailto:cfrg-request@irtf.org?subject=help>
List-Subscribe: <http://www.irtf.org/mailman/listinfo/cfrg>, <mailto:cfrg-request@irtf.org?subject=subscribe>
X-List-Received-Date: Thu, 31 Jul 2014 21:09:25 -0000

On Thu, Jul 31, 2014 at 10:23 AM, Daniel Kahn Gillmor <dkg@fifthhorseman.net
> wrote:

> neither of these required nationstate-level effort, and they date back
> to 2008.


Okay, let me put it this way instead:

Collisions:

- Can be used to alter the content of individual messages
- This requires that the design of the hash function itself be broken

Bad nonces:

- Leak the private key which can then be used to forge as many messages as
you wish
- Can be the result of bad RNGs/implementation errata even if the algorithm
and the rest of its implementation is sound

Which is worse?

-- 
Tony Arcieri

v2.23.0 | Report a Bug | By Email