IETF Logo Mail Archive

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

Tony Arcieri <bascule@gmail.com> Thu, 31 July 2014 17:09 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 841811A02D1 for <cfrg@ietfa.amsl.com>; Thu, 31 Jul 2014 10:09:24 -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 9j_YojLGadi1 for <cfrg@ietfa.amsl.com>; Thu, 31 Jul 2014 10:09:20 -0700 (PDT)
Received: from mail-vc0-x22c.google.com (mail-vc0-x22c.google.com [IPv6:2607:f8b0:400c:c03::22c]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 08F541A02DB for <cfrg@irtf.org>; Thu, 31 Jul 2014 10:09:19 -0700 (PDT)
Received: by mail-vc0-f172.google.com with SMTP id im17so4735622vcb.17 for <cfrg@irtf.org>; Thu, 31 Jul 2014 10:09:18 -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=hE2a9HHY+BfjQtHKVdsL1dOz0wR8Z3JR60OnqK7+Wbw=; b=C0yvbT6Fg33cdJMa42fTZa2p+rcPJ2VsQPTG4cN+fLb+580/iijF3LiGXi96mfnCnY fWjsIa+tZV8+tjRv6B593QqpayWZYEMEBVZhZhhvzupHbrBFHMOVYsjNZyX/N3QZsFvK cmdxlm08P8hMINW47Bg04918sYzKLRdeErsypXpYePJm0UhX2gjEbvLRuVJ3O6QGHBla U4pEq1IQtYVKTbvLObdM18K4IiXJftrQ/KJ0WD115Tw09H5QmvpVT97Y37gUkOPZw7CF YBdShcMAGjm4ZsJIJuUSa0ZZupJO6xAMqnxIiux7fGo3J0vjV/p0l0YXvpwVS390JB4g KokQ==
X-Received: by 10.52.246.198 with SMTP id xy6mr16421504vdc.7.1406826558644; Thu, 31 Jul 2014 10:09:18 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.58.160.10 with HTTP; Thu, 31 Jul 2014 10:08:58 -0700 (PDT)
In-Reply-To: <947D45A1-AF36-470B-8D50-7600FEF7FB30@shiftleft.org>
References: <20140729205846.6639765.71649.17355@certicom.com> <CAHOTMVJ4AirY+tRnVfwt1umgx=Q2xNwVTks6OoVNaV0gkKihOg@mail.gmail.com> <947D45A1-AF36-470B-8D50-7600FEF7FB30@shiftleft.org>
From: Tony Arcieri <bascule@gmail.com>
Date: Thu, 31 Jul 2014 10:08:58 -0700
Message-ID: <CAHOTMVJYr=S1fXXSYCHDJz2m6sn10uQ=ztXT7htW1m53qEZHog@mail.gmail.com>
To: Michael Hamburg <mike@shiftleft.org>
Content-Type: multipart/alternative; boundary="001a1133b89049e92a04ff805530"
Archived-At: http://mailarchive.ietf.org/arch/msg/cfrg/axlz_BGbUmNFiKa1Ww1RLHlZE4Q
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 17:09:25 -0000

On Thu, Jul 31, 2014 at 12:40 AM, Michael Hamburg <mike@shiftleft.org>
wrote:

> Indeed.  But collision attacks have also broken signature schemes *in
> practice*, for example the Flame malware.
>

Are there any other examples of collision attacks in the wild? Also note
this attack required a nationstate-level effort.

Attacks on bad nonces are comparatively common and relatively easy, e.g.
someone automated stealing of other's Bitcoins by detecting nonce reuse in
the BitCoin block chain:

https://bitcointalk.org/index.php?topic=271486.0


>  You can have any two of determinism, one-pass signatures, and protection
> from collision attacks.  So far as I know, you can’t have all three, at
> least not with a Schnorr scheme.  Please correct me if I’m wrong.
>

I think you're correct


> Or should we drop protection from collision attacks?


Probably, unless there's evidence they're a real threat.

-- 
Tony Arcieri

v2.27.8 | Report a Bug | By Email | System Status