Peter Gutmann himself wrote the following:

If you're using a drive which uses encoding technology X, you only need to perform the passes specific to X, and you never need to perform all 35 passes. For any modern PRML/EPRML drive, a few passes of random scrubbing is the best you can do. As the paper says, "A good scrubbing with random data will do about as well as can be expected". This was true in 1996, and is still true now.


It seems like the method of data reconstruction described in the paper is more of an academic problem than something that is done in real life.

Nonetheless many data erasure tools are implementing the Gutmann method. (For example DBAN, Recuva, shred, TrueCrypt) Is there any real life scenario where the Gutmann method is actually needed? Or do they just provide it as a feel-good feature for paranoid users?

  • 1
    Please read this excellent answer: security.stackexchange.com/a/10474/9792
    – dan
    Jul 18 '17 at 12:08
  • @daniel Azuelos so this means the answer is "there is no real life scenario and the implementation is added with no reason"?
    – floworbit
    Jul 18 '17 at 13:04
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    Yes. For sensitive information I don't use the 7 and 35 passes schemes since 15 years.
    – dan
    Jul 18 '17 at 15:52

Assuming an adversary is able to get data off the raw chips, over-provisioning on solid state drives could leave data behind after a single wipe. In this scenario multiple passes would help remove data on the extra storage. Depending on what kind of data and adversaries you have 10+ passes could be justified, though why you wouldn't just destroy the drive and chips at that point is beyond me.

  • 1
    "though why you wouldn't just destroy the drive and chips at that point is beyond me." - Good point, but it could be you do not have physical access to the drives, or the authority to destroy physical media within a company. Destroying the physical asset may require more 'red tape' to get sign off from senior management. The company may (correctly or incorrectly) have a policy on reuse of drives within a given time frame.
    Jul 18 '17 at 12:56

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