[ale] Wiping hard drives revisited...

[tom]

On Sat, 17 Jan 2009, Michael H. Warfield wrote:

> 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."
>
Well, apparently there goes the need for thermite fusing followed by HF 
digestion...

Or was it the other way around??