From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lists.gentoo.org ([140.105.134.102] helo=robin.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1IdlkG-0001vz-A2 for garchives@archives.gentoo.org; Fri, 05 Oct 2007 11:53:28 +0000 Received: from robin.gentoo.org (localhost [127.0.0.1]) by robin.gentoo.org (8.14.1/8.14.0) with SMTP id l95Bh06g005597; Fri, 5 Oct 2007 11:43:00 GMT Received: from gabriel.sub.uni-goettingen.de (gabriel.sub.uni-goettingen.de [134.76.163.126]) by robin.gentoo.org (8.14.1/8.14.0) with ESMTP id l95Bcfr2000645 for ; Fri, 5 Oct 2007 11:38:42 GMT Received: by gabriel.sub.uni-goettingen.de (Postfix, from userid 8) id 08E053246B4; Mon, 8 Oct 2007 05:49:35 +0200 (CEST) Received: from localhost (unknown [134.76.161.221]) by gabriel.sub.uni-goettingen.de (Postfix) with ESMTP id 7260B3246B3 for ; Mon, 8 Oct 2007 05:49:33 +0200 (CEST) Date: Fri, 5 Oct 2007 13:38:39 +0200 From: Hans-Werner Hilse To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Can RAM render useless the encryption of the / and swap partitions? Message-Id: <20071005133839.a83efe0e.hilse@web.de> In-Reply-To: <68b1e2610710041133q2908483cu7877a6b197460922@mail.gmail.com> References: <68b1e2610710032342j1b47ff5g8f868d8fcc0179ef@mail.gmail.com> <200710041547.53084.alan@linuxholdings.co.za> <20071004163457.2bf0ad43.hilse@web.de> <200710041857.51348.alan@linuxholdings.co.za> <68b1e2610710041133q2908483cu7877a6b197460922@mail.gmail.com> X-Mailer: Sylpheed 2.4.5 (GTK+ 2.12.0; i586-pc-linux-gnu) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@gentoo.org Reply-to: gentoo-user@lists.gentoo.org Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.64 (2004-01-11) on gabriel.sub.uni-goettingen.de X-Spam-Level: X-Spam-Status: No, hits=-2.7 required=5.0 tests=AWL,BAYES_00 autolearn=ham version=2.64 X-Archives-Salt: 491e38d1-b414-4857-88c8-cb99e97d3c64 X-Archives-Hash: ab5ab5d7c3c31ca3c0b93fbf651ead73 Hi, On Thu, 4 Oct 2007 20:33:40 +0200 "Liviu Andronic" wrote: > On 10/4/07, Alan McKinnon wrote: > > On Thursday 04 October 2007, Hans-Werner Hilse wrote: > > > However, it makes sense to clean up memory after having > > > critical data in it -- e.g. a reboot doesn't necessarily clean up > > > RAM. > > > > Yes, this is very true > > BUT > > On 10/4/07, Alan McKinnon wrote: > > Pray tell, how does RAM manage to retain data when the power is off? > > ...and... > On 10/4/07, Volker Armin Hemmann > wrote: > > In practice, after power is cut, everything in ram is lost. > > So, my eternal question, is it realistic for the "lost" RAM data to be > recovered? That is, after system shutdown, does the data still > physically reside on the RAM and can someone with a decent technology > and know-how recover it? In other words, is this a serious breach in > any encrypted system? No, it isn't. Well, I didn't had the full circuit design of today's DRAMs in mind, and yes, since there's the resistor, the capacitor will lose its load (very) soon (/me scratches his head, wasn't there something asymptotically in that graph? But in any way, it would be a difference of very few electrons on the sides of the capacitor) -- that's not a security breach. But: We are talking about _powering_ _off_ the DRAM. You are talking about shutting down. That might be two different things and completely depend on hardware design. Make shure that RAM's gonna get powered off and you're save. So pulling the plug should give you a warm good feeling in that regard. Doing a "sudo halt", however, _might_ have other consequences and we cannot make a general assumption on that. Even pulling the plug might have problems: There's such thing as battery-buffered RAM (although I think they've used it mainly in the pre-Flash era). The thing is: You never can guarantee security, that's absolutely impossible (well, of course you can, but you would automatically be wrong). You can do all your best, but that's about it. Having security is a thing you can falsify, but never verify, since theorys can't be verified without dogmas (and there are no accepted dogmas that would help here). -hwh -- gentoo-user@gentoo.org mailing list