From owner-freebsd-security Thu Nov 18 21: 5:11 1999 Delivered-To: freebsd-security@freebsd.org Received: from alcanet.com.au (border.alcanet.com.au [203.62.196.10]) by hub.freebsd.org (Postfix) with ESMTP id 7EC2A1508E for ; Thu, 18 Nov 1999 21:05:08 -0800 (PST) (envelope-from jeremyp@gsmx07.alcatel.com.au) Received: by border.alcanet.com.au id <40400>; Fri, 19 Nov 1999 15:58:28 +1100 Content-return: prohibited Date: Fri, 19 Nov 1999 16:04:55 +1100 From: Peter Jeremy Subject: Re: secure filesystem wiping In-reply-to: To: Barrett Richardson Cc: freebsd-security@FreeBSD.ORG Reply-To: peter.jeremy@alcatel.com.au Message-Id: <99Nov19.155828est.40400@border.alcanet.com.au> MIME-version: 1.0 X-Mailer: Mutt 1.0pre3i Content-type: text/plain; charset=us-ascii References: <38347633.22E76DE0@softweyr.com> Sender: owner-freebsd-security@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On 1999-Nov-19 15:37:34 +1100, Barrett Richardson wrote: >How about pseudo-random data? Aren't the passes with random data just >a little extra icing? As I understand the recovery techniques, it's irrelevant because the difference between the current data and the previous generation is quite clear (otherwise the normal read wouldn't work). This means you can immediately extract the pattern used to perform the over-write (whatever it is) and subtract an idealised version of it to leave you with the underlying data/ >Also, will my system choke if I mmap a 250 MB file on a system >with 32 MB of ram? Nope. Peter To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message