When Erasing a Hard Drive, Deleting Is Not Enough

As an example, the BBC is reporting that 22,000 "deleted" files were recovered from eight computers bought off of eBay. These files could contain your Social Security number, address, bank account numbers, and just about any other sensitive data that should remain private. The issue is that "deleting" files, or even reformatting a hard drive does not actually remove the data -- it simply removes any direct pointers to it. This is why data recovery software and experts (and savvy crooks) can bring back files from the dead.
So is all hope lost? Not at all. One fairly secure method, as shown in the BBC video, is to smash the hard drive into pieces. A less extreme but just as effective method is to overwrite the hard drive with random data or zeroes. Think of it as scrubbing the data away with useless garbage. Luckily, the tools to do so are readily available, and free. If you're a Windows user, Eraser is a great little utility that can securely erase files on the fly, and also overwrite any free space on a drive.
If you're a Mac user, just open OSX's included Disk Utility application, select the disk you want to erase, and open the Security Options. Then select one of the three methods -- Zero Out, 7-Pass, or 35-Pass -- and you'll be good to go. If you want to just securely empty your Trash Can and not clean the whole drive, make sure the Finder is selected, and choose "Secure Empty Trash" from the Finder menu list.



Reader Comments (Page 1 of 1)
Burn Your Disc for Real said 2:17PM on 1-09-2009
Smash the drive into little pieces? Not good enough, as the pieces still contain magnetic data that can be read. The real solution is to put your hard drive to the torch. I put my old drive under a garden-type weed-burning torch until the disk just curled up into a blackened and smoke-belching mass of unidentifiable goo. Now THAT'S security!
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Kate F said 2:28PM on 1-09-2009
Haha, last time I destroyed a drive I did a 7 pass zero out (military standard) then proceeded to disassemble the drive, scratched the disks, passed a rare earth magnet over it a few times then broke it (the disks) into many many pieces and trashed it over a period of a month in different places.
I'm paranoid, and I work with sensitive information with no access to a degaussing machine. What can I say?
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