[wellylug] Darik's Boot and Nuke ("DBAN") HDD eraser

[Atom Smasher]

On Wed, 2 Jun 2010, Daniel Pittman wrote:

>> if you fill a modern drive with zeros there is NO WAY to recover any 
>> data previously stored on the drive... unless the drive is taken apart 
>> and subject to VERY expensive, time consuming and unreliable data 
>> recovery techniques.
>
> Well, it isn't that expensive: remapped bad sectors, and stray writes 
> outside the track, can be recovered for as little as a few tens of 
> thousands of dollars.  (...and prices may have dropped since I last 
> looked.)
=================

recovering bad sectors, it makes no difference if the rest of the drive 
(good sectors) is filled with zeros or random bits. the *ONLY* way to 
overwrite bad sectors with modern commodity hardware is with the ATA 
secure erase function.


>> so unless you've pissed off the CIA, zeros are fine. this assumes that 
>> you're using a drive that was made within the last 10-20 years...
>
> *nod* As I note, a single pass overwrite with zero is enough for the .au 
> government, so anything more than that is going to be above and beyond.
==============

the US standards are... let me say "more thorough". but only because 
they're outdated. in the 70s it almost made sense to retire a sensitive 
disk by writing a dozen special passes to it, then burning it and 
scattering the ashes throughout several secure sites. now it's useless, 
aside from the therapeutic value. but those procedures are still followed 
by a lot of govts and corps that could otherwise give the disks a new 
home... meanwhile plenty of disks from ATM machines, photocopiers and even 
computers are still easy to find second hand with the sensitive data FULLY 
INTACT.


-- 
         ...atom

  ________________________
  http://atom.smasher.org/
  762A 3B98 A3C3 96C9 C6B7 582A B88D 52E4 D9F5 7808
  -------------------------------------------------

 	"The law does not allow me to testify on any
 	 aspect of the National Security Agency,
 	 even to the Senate Intelligence Committee."
 		-- General Allen, Director of the NSA, 1975