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 1IdS2g-0003e6-Hx for garchives@archives.gentoo.org; Thu, 04 Oct 2007 14:51:11 +0000 Received: from robin.gentoo.org (localhost [127.0.0.1]) by robin.gentoo.org (8.14.1/8.14.0) with SMTP id l94Eeh18001332; Thu, 4 Oct 2007 14:40:43 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 l94EYwoJ025488 for ; Thu, 4 Oct 2007 14:34:58 GMT Received: by gabriel.sub.uni-goettingen.de (Postfix, from userid 8) id 889583246B4; Sun, 7 Oct 2007 07:10:22 +0200 (CEST) Received: from localhost (unknown [134.76.161.221]) by gabriel.sub.uni-goettingen.de (Postfix) with ESMTP id BEBC93246B3 for ; Sun, 7 Oct 2007 07:10:21 +0200 (CEST) Date: Thu, 4 Oct 2007 16:34:57 +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: <20071004163457.2bf0ad43.hilse@web.de> In-Reply-To: <200710041547.53084.alan@linuxholdings.co.za> References: <68b1e2610710032342j1b47ff5g8f868d8fcc0179ef@mail.gmail.com> <200710041547.53084.alan@linuxholdings.co.za> 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=-2.6 required=5.0 tests=AWL,BAYES_00 autolearn=ham version=2.64 X-Archives-Salt: f4fd0705-d0ca-4169-8777-7bc4b8da98e8 X-Archives-Hash: 359439a8e43cb5a9e41c0dbb788d1f70 Hi, On Thu, 4 Oct 2007 15:47:53 +0200 Alan McKinnon wrote: > On Thursday 04 October 2007, Liviu Andronic wrote: > > And later on: "Now one problem is > > left. Even with normal RAM a well funded organisation can get the > > contents after the system is powered off. With the modern SDRAM it's > > even worse, where the data stays on the RAM permanently until new > > data is written. > > Pray tell, how does RAM manage to retain data when the power is off? > It's either six transistors or one transistor and a cap per cell = > not persistent. In theory, for the one transistor and one cap case, you have a loaded cap that will take "forever" losing its load, won't it? But in practice, I think, that's not realistic. > I don't know of any magic persistent RAM that's fast enough for use > as main RAM. Flash disks are of course another story but you do > appear to be talking about system RAM There actually are new RAM types being made for solid-state storage. But this is in a proof-of-concept stage, I think. Maybe Liviu's professor had those magnetic drum memory units in mind when saying that? Anyway, cleaning memory on a power-off shut down doesn't make much sense. However, it makes sense to clean up memory after having critical data in it -- e.g. a reboot doesn't necessarily clean up RAM. And I'm not sure if some mainboards even keep the RAM powered in certain situations -- at least, they can as long as the power is not really switched off (e.g. machine only in ATX soft-off mode). -hwh -- gentoo-user@gentoo.org mailing list