From owner-freebsd-security Fri May 21 20:37:28 1999 Delivered-To: freebsd-security@freebsd.org Received: from xylan.com (postal.xylan.com [208.8.0.248]) by hub.freebsd.org (Postfix) with ESMTP id 8E52F14F44 for ; Fri, 21 May 1999 20:37:26 -0700 (PDT) (envelope-from wes@softweyr.com) Received: from mailhub.xylan.com by xylan.com (8.8.7/SMI-SVR4 (xylan-mgw 2.2 [OUT])) id UAA29116; Fri, 21 May 1999 20:37:23 -0700 (PDT) Received: from omni.xylan.com by mailhub.xylan.com (SMI-8.6/SMI-SVR4 (mailhub 2.1 [HUB])) id UAA13713; Fri, 21 May 1999 20:37:23 -0700 Received: from softweyr.com ([204.68.178.39]) by omni.xylan.com (4.1/SMI-4.1 (xylan engr [SPOOL])) id AA04565; Fri, 21 May 99 20:37:16 PDT Message-Id: <3746266A.73D34043@softweyr.com> Date: Fri, 21 May 1999 21:37:14 -0600 From: Wes Peters Organization: Softweyr LLC X-Mailer: Mozilla 4.5 [en] (X11; U; FreeBSD 3.1-RELEASE i386) X-Accept-Language: en Mime-Version: 1.0 To: Snob Art Genre Cc: freebsd-security@FreeBSD.ORG Subject: Re: secure deletion References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-security@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Snob Art Genre wrote: > > So I can see some use for functionality that overwrites files on unlink() > thoroughly enough to prevent further reading by the disk head, even if it > offers no protection against the kind of specialized reading devices that > can be used on a captured hard disk platter. > > I'm not advocating this measure so much as pointing out that there is a > perceptible level of security between what we currently have and > military-grade. I agree, if your security measures cost more than the worth of your data, you're shooting yourself in the foot. But, on the other hand, if you're going to implement a page- or file-overwriting algorithm, you might as well use one that has some chance of success, as opposed to the "pissing in the wind" effort of overwriting them with zeroes. The pattern used in rm -P is a step in the right direction, but alter- nating bits works better than successive generations of all ones then all zeroes. -- "Where am I, and what am I doing in this handbasket?" Wes Peters Softweyr LLC http://www.softweyr.com/~softweyr wes@softweyr.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message