Date: Thu, 18 Nov 1999 22:27:48 -0700 From: Wes Peters <wes@softweyr.com> To: Dug Song <dugsong@monkey.org> Cc: Jonathon McKitrick <jcm@dogma.freebsd-uk.eu.org>, security@FreeBSD.ORG, questions@FreeBSD.ORG Subject: Re: secure filesystem wiping Message-ID: <3834DFD4.95D08AFD@softweyr.com> References: <Pine.BSO.4.10.9911181606420.12081-100000@funky.monkey.org>
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Dug Song wrote: > > On Thu, 18 Nov 1999, Jonathon McKitrick wrote: > > > Why isn't it possible to read unallocated sectors and write back sectors > > full of garbage, or 0xFF? > > this was the topic of a recent thread on comp.security.unix: > > peter gutmann's excellent paper from the 6th USENIX security symposium is > probably the definitive answer: > > http://www.fish.com/security/secure_del.html That's the algorithm my "obliterate" program uses, modulo caching in the disk controller, etc. The idea occurred to me this afternoon it would be relatively easy to wipe the unallocated sectors of a disk if it were unmounted, right after a fsck or maybe as a final optional pass to fsck. Such an operation would be excruciatingly slow on a disk of any size, though. -- "Where am I, and what am I doing in this handbasket?" Wes Peters Softweyr LLC wes@softweyr.com http://softweyr.com/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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