Full Disclosure mailing list archives
Re: Disk wiping -- An alternate approach?
From: T Biehn <tbiehn () gmail com>
Date: Tue, 26 Jan 2010 11:33:09 -0500
Are you suggesting that consumer magnet-based storage solutions use the same technology that the recovery machines use to store more than one bit in what you consider a 'single bit location' ? I think it would be cost and space prohibitive, not dependent on any algorithm. If I'm thinking correctly, and I have no real idea how the recovery process works, the recovery machines measure minute variance in the analog magnetic signal directly pulled from the platters to figure out what bits 'used' to be on the disk in that location. I sincerely doubt that anything consumer accessible would be able to work with that. I also doubt that it is exact, and protocols probably use probabilistic methods for extraction of a given content; text for example. Given a block of bits, the signal variance from 'clean' on those bits (eg if never written) is x. x is matched with a dictionary of known text. Anyone know to confirm? -Travis On Tue, Jan 26, 2010 at 11:15 AM, Christian Sciberras <uuf6429 () gmail com> wrote:
It would be a part of the algorithm, to make sure the overwritten file is readable. But if those machines get any smaller, I guess these would be the next generation of storage media take bluerays vs dvds for example. On Tue, Jan 26, 2010 at 5:11 PM, T Biehn <tbiehn () gmail com> wrote:Overwritten files require analysis with a 'big expensive machine.' I doubt they ever recover the full file. -Travis On Tue, Jan 26, 2010 at 11:04 AM, Christian Sciberras <uuf6429 () gmail com> wrote:I was thinking, since all this (reasonable) fuss on wiping a disk over 10 times to ensure non-readability, how come we're yet very limited on space usage? If, for example, I overwrote a bitmap file with a text one, what stops the computer from recovering/storing both (without using additional space)? Just a couple curiosities of mine. On Tue, Jan 26, 2010 at 4:08 PM, Michael Holstein <michael.holstein () csuohio edu> wrote:By the way, does somebody knows about the flash memory? Is zeroing a whole usb key enough to make the data unrecoverable?No, wear-leveling (done at the memory controller level) will dynamically re-map addresses on the actual flash chip to ensure a relatively consistent number of write cycles across the entire drive. The only way to completely "wipe" a flash disk is with a hammer. Regards, Michael Holstein Cleveland State University _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/_______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/-- FD1D E574 6CAB 2FAF 2921 F22E B8B7 9D0D 99FF A73C http://pgp.mit.edu:11371/pks/lookup?search=tbiehn&op=index&fingerprint=on http://pastebin.com/f6fd606da
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Current thread:
- Re: Disk wiping -- An alternate approach?, (continued)
- Re: Disk wiping -- An alternate approach? Bipin Gautam (Jan 25)
- Re: Disk wiping -- An alternate approach? Bipin Gautam (Jan 25)
- Re: Disk wiping -- An alternate approach? Tracy Reed (Jan 25)
- Re: Disk wiping -- An alternate approach? E. Prom (Jan 25)
- Re: Disk wiping -- An alternate approach? Bipin Gautam (Jan 25)
- Re: Disk wiping -- An alternate approach? Michael Holstein (Jan 26)
- Re: Disk wiping -- An alternate approach? Christian Sciberras (Jan 26)
- Re: Disk wiping -- An alternate approach? T Biehn (Jan 26)
- Re: Disk wiping -- An alternate approach? T Biehn (Jan 26)
- Re: Disk wiping -- An alternate approach? Christian Sciberras (Jan 26)
- Re: Disk wiping -- An alternate approach? T Biehn (Jan 26)
- Re: Disk wiping -- An alternate approach? Valdis . Kletnieks (Jan 26)
- Re: Disk wiping -- An alternate approach? T Biehn (Jan 26)
- Re: Disk wiping -- An alternate approach? T Biehn (Jan 26)
- Re: Disk wiping -- An alternate approach? E. Prom (Jan 26)
- Re: Disk wiping -- An alternate approach? Stefan Weimar (Jan 26)
- Message not available
- Re: Disk wiping -- An alternate approach? Michael Holstein (Jan 26)
- Re: Disk wiping -- An alternate approach? Michael Holstein (Jan 26)