From owner-freebsd-hackers@FreeBSD.ORG  Mon Nov 24 22:24:10 2003
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP
	id D3B0E16A4CE; Mon, 24 Nov 2003 22:24:10 -0800 (PST)
Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.86.163])
	by mx1.FreeBSD.org (Postfix) with ESMTP
	id 34E1343FE0; Mon, 24 Nov 2003 22:24:09 -0800 (PST)
	(envelope-from phk@phk.freebsd.dk)
Received: from critter.freebsd.dk (localhost [127.0.0.1])
	by critter.freebsd.dk (8.12.10/8.12.10) with ESMTP id hAP6O3Dx032477;
	Tue, 25 Nov 2003 07:24:04 +0100 (CET)
	(envelope-from phk@phk.freebsd.dk)
To: Stefan =?iso-8859-1?Q?E=DFer?= <se@freebsd.org>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Tue, 25 Nov 2003 00:57:38 +0100."
             <20031124235738.GA4107@StefanEsser.FreeBSD.org> 
Date: Tue, 25 Nov 2003 07:24:03 +0100
Message-ID: <32476.1069741443@critter.freebsd.dk>
cc: Dag-Erling =?iso-8859-1?Q?Sm=F8rgrav?= <des@des.no>
cc: Rayson Ho <raysonlogin@yahoo.com>
cc: freebsd-hackers@freebsd.org
Subject: Re: "secure" file flag? 
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 25 Nov 2003 06:24:10 -0000

In message <20031124235738.GA4107@StefanEsser.FreeBSD.org>, Stefan =?iso-8859-1

>And that is what this thread is about: Secure removal of data from 
>storage media. There definitely is a difference between RLL (as in 
>1,7i RLL) and modern PRML drives under this aspect.

No there isn't.

It's been proven again and again that you cannot reliably overwrite
data on a magnetic media.  In particular the difference in read/write
geometry and lack of fine control over head placement makes this
impossible.

The only reliable way to loose data is to encrypt them and throw the
key away.

Live with it.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.