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I just got a program that can "shred" files so they cannot be recovered. It offers 4 erasing methods:

  • Random Data Method (1 pass)
  • US DoD 5200.22M-STD (3 passes)
  • US DoD 5200.28-STD (7 passes)
  • Peter Gutmann Method (35 passes)

The program claims that the Gutman algorithm is the most secure, however I've read that that method is not necessary now with modern hard drives (not SSDs) and only a few passes or random scrubbing should be enough.

Which is the most secure method (with out actually having to physically destroy the drive)?

diego
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1 Answers1

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The Gutmann method is in fact the most secure, and IIRC was developed based on principals of electo-magnetics in his academic paper 'Secure Deletion from Magnetic and Solid State Media', so its a theoretically secure solution. per a cryptographic definition of "perfect secrecy" he is correct, because when you overwrite a disk, it is possible to make assumptions about the files that were on it, and it can be proven that a given known file has been present on a disk, even if you can't read it now, per his findings. his algorithm is designed to defeat that potential.

In the Practical realm, it is almost impossible to recover data that has been overwritten once unless the attacker knows something about the data they are attempting to recover. This has been proven a number of times. Note that this has nothing to do with the moderness of the disk.

https://raufakram.wordpress.com/2013/05/23/why-you-only-have-to-wipe-a-disk-once-to-erase-it/

ultimately , if you are facing an adversary with unlimited capability (FBI) use Guttman. if you are worried about wiping a PC before you put it up for sale, single pass is fine. http://blogs.computerworld.com/node/5687

Frank Thomas
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