From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from tansi.org (ns.km10532-04.keymachine.de [87.118.102.195]) by mail.saout.de (Postfix) with ESMTP for ; Sun, 22 Aug 2010 01:14:01 +0200 (CEST) Received: from gatewagner.dyndns.org (84-74-164-239.dclient.hispeed.ch [84.74.164.239]) by tansi.org (Postfix) with ESMTPA id 28B261218525 for ; Sun, 22 Aug 2010 01:14:01 +0200 (CEST) Date: Sun, 22 Aug 2010 01:14:00 +0200 From: Arno Wagner Message-ID: <20100821231400.GA30794@tansi.org> References: <20100726210741.GC24052@tansi.org> <1280180557.3266.136.camel@fermat.scientia.net> <4C682354.50907@web.de> <20100815221051.GA13494@tansi.org> <1281963344.4c69355004f56@www.inmano.com> <20100816142139.GA26251@tansi.org> <1282423535.3276.24.camel@fermat.scientia.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: <1282423535.3276.24.camel@fermat.scientia.net> Subject: Re: [dm-crypt] Efficacy of xts over 1TB List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: dm-crypt@saout.de On Sat, Aug 21, 2010 at 10:45:35PM +0200, Christoph Anton Mitterer wrote: > Hi. >=20 >=20 > But this goes IMO more in the plausible denyability direction, doesn't > it? I think not even that. The attacker already know you likely have encrypted data or a lot of randomness. But then you have been changing that in a typical pattern for filesystem access. The data leakage is real, but very, very low in volume and will not matter in almost all situations IMO, and therefore nobody will bother attacking that. Now if you store and process highly sensitive data in the exabyte-range, it might be a minor concern (an attacker could plant a document and later detect ot has been added to the encrypted device), but even there effort is extreme.=20 This is an example of an academic attack. Interesting, and show a real limit of the employed encryption method, but irrelevant for the real world. > An attacker would still be not able to read what was written. > And for most applications it should be extremely difficult or even > impossible to make any conclusions,.. because of fragmentation... etc. > pp. I agree. > Another issue is of course when you have corrupted programs in the > system.... but then you're screwed anyway,... and there are usually much > easier to implement hidden channels.... (but this argument shouldn't > count as I always say myself ;) ). Indeed. Just use a sequence of secors, and change or not them=20 in a pattern. Arno --=20 Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.nam= e=20 GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F ---- Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans If it's in the news, don't worry about it. The very definition of=20 "news" is "something that hardly ever happens." -- Bruce Schneier=20