[ale] Wiping hard drives revisited...

[Jim Kinney]

Cool! Thanks Michael.

I've always been of the opinion that any organization with the means,
technical and/or financial, to extract data from a single pass of 'dd
if=/dev/zero of=/dev/sda' has also the resources to make me and my
family "disappear" until the drive contents are "recovered". That is a
bigger and more challenging problem that how clean is the drive.

2009/1/17 Michael H. Warfield <mhw at wittsend.com>:
> Hey all,
>
>        I think it was after my talk on extreme data recovery that several of
> us got into the old discussion over wiping data and number of passes and
> recovering data with a microscope and all.  My position for a long time
> has been that it's virtually impossible with modern high density hard
> drives and the old "multiple pass" wisdom was largely from the days of
> tapes (reel to reel tapes tapes at that).  I don't recall who was
> arguing the counterpoint that they could recover data with a magnetic
> field microscope and all.  Seems that someone has actually gone and
> researched it and actually tested it.  Thought everyone would find this
> interesting as a follow on to that debate:
>
>        Single drive wipe protects data, research finds
>        http://www.securityfocus.com/brief/888
>
>        Single pass wipe: "Recovering a single byte of data, for example, on a
> used drive is successful less than one percent of the time, he found.
> Accurately recovering four bytes, or 32 bits, of data only works nine
> times out of each million tries."
>
>        "In many instances, using a MFM (magnetic force microscope) to
> determine the prior value written to the hard drive was less successful
> than a simple coin toss."
>
> --
> Michael H. Warfield (AI4NB) | (770) 985-6132 |  mhw at WittsEnd.com
>   /\/\|=mhw=|\/\/          | (678) 463-0932 |  http://www.wittsend.com/mhw/
>   NIC whois: MHW9          | An optimist believes we live in the best of all
>  PGP Key: 0xDF1DD471        | possible worlds.  A pessimist is sure of it!
>
>
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> http://mail.ale.org/mailman/listinfo/ale
>
>



-- 
-- 
James P. Kinney III