Fast and secure HDD erase?

Discussion in 'Computer Security' started by Robert Wegner, Sep 12, 2006.

  1. Hi,

    i wonder, is there a faster alternative than to overwrite a HDD n-times,
    if i want the data reasonably securely destroyed (without destroying the HDD
    itself)?
    I got the problem that i have 4 x 250GB HDDs which need to be erased.
    But with the deletion tools i know, which overwrite the whole disk n-times
    it takes me up to 2 days just for one of them.


    thanks,
    rob
    Robert Wegner, Sep 12, 2006
    #1
    1. Advertising

  2. Robert Wegner

    hdtv? Guest

    "Robert Wegner" <> wrote in message
    news:...
    > Hi,
    >
    > i wonder, is there a faster alternative than to overwrite a HDD n-times,
    > if i want the data reasonably securely destroyed (without destroying the
    > HDD
    > itself)?
    > I got the problem that i have 4 x 250GB HDDs which need to be erased.
    > But with the deletion tools i know, which overwrite the whole disk
    > n-times
    > it takes me up to 2 days just for one of them.
    >
    >
    > thanks,
    > rob
    >

    The new DoD standard states that hdd's above 15GB can be erased with one
    over write.

    I generally use Maxtor low level format and write 3 times.
    hdtv?, Sep 12, 2006
    #2
    1. Advertising

  3. Robert Wegner wrote:

    > Hi,
    >
    > i wonder, is there a faster alternative than to overwrite a HDD n-times,
    > if i want the data reasonably securely destroyed (without destroying the HDD
    > itself)?


    Yes. A very large magnet. In fact the US military is implementing a
    magnetic erase feature for the hard drives in aircraft flight recorders
    and such so that downed planes can't reveal useful information. It's
    thought to be more thorough and secure than conventional methods.

    You'd have to research the ramifications, but if you believe it
    wouldn't destroy consumer quality drives you might look for a local
    tool or machine shop that has what's called a "demagnetizer". You might
    want to remove the drive controller first, I'm not sure how something
    like that would affect the electronics. Not as big a project as you'd
    think with most drives, just a couple screws and a connector.

    If you want to spend the money, several companies make drive degauss
    tools. Fujtsu calls theirs "Mag EraSURE", but I'm not sure what it
    costs or how secure it is. I'd imagine it's secure enough just to pass
    the drive on to an average Joe. Google is your friend, I'd start with
    something like 'bulk hard drive erasure'.
    George Orwell, Sep 12, 2006
    #3
  4. "Robert Wegner" <> wrote in message
    news:...
    > Hi,
    >
    > i wonder, is there a faster alternative than to overwrite a HDD n-times,
    > if i want the data reasonably securely destroyed (without destroying the
    > HDD
    > itself)?
    > I got the problem that i have 4 x 250GB HDDs which need to be erased.
    > But with the deletion tools i know, which overwrite the whole disk
    > n-times
    > it takes me up to 2 days just for one of them.
    >
    >
    > thanks,
    > rob


    First, go back to the thread here of Aug31 'can't find an answer'.
    Then consider the value and sensitvity of the data.
    Is somebody going to want to look at many millions of sectors and try to
    reconstruct files?
    Or take the drive apart and examine the platters?
    If not, then a few formats, preferable with different file systems will do
    ie do it in ntfs, then fdisk, delete partitions, do it in fat32, delete,
    then in a linux file system.
    That will slow them down enough that it is no longer worth the effort unless
    this might be evidence in a criminal trial.

    Stuart
    Stuart Miller, Sep 12, 2006
    #4
  5. Robert Wegner

    Arthur T. Guest

    In Message-ID:<>,
    Robert Wegner <> wrote:

    >i wonder, is there a faster alternative than to overwrite a HDD n-times,
    >if i want the data reasonably securely destroyed (without destroying the HDD
    >itself)?
    >I got the problem that i have 4 x 250GB HDDs which need to be erased.
    >But with the deletion tools i know, which overwrite the whole disk n-times
    >it takes me up to 2 days just for one of them.


    I'm not one of the deep experts that hangs out here, but I
    strongly expect that the answer is "No".

    However, in order to speed up your erasure, have you
    considered:

    1. Running all 4 at the same time? Depending on where the
    slow-down is, this could take anywhere from 25% of the time up to
    a bit over 100%.

    2. What do you have "n" set to? Would you feel comfortable
    lowering it to, say, 2? I think that even n=1 would stymie
    anything short of clean-room techniques. (Would a real expert
    comment on my n=1 conjecture, please?)

    3. Start the erasures, now. By the time you get enough people to
    answer this, you could probably have at least one of them already
    erased.

    --
    Arthur T. - ar23hur "at" intergate "dot" com
    Looking for a good MVS systems programmer position
    Arthur T., Sep 12, 2006
    #5
  6. George Orwell wrote:

    > Robert Wegner wrote:
    >
    >> Hi,
    >>
    >> i wonder, is there a faster alternative than to overwrite a HDD n-times,
    >> if i want the data reasonably securely destroyed (without destroying the HDD
    >> itself)?

    >
    > Yes. A very large magnet.


    Keeping the HDD intact doesn't mean that you're supposed to magnetize the
    package and destroying the electronics around the plates.
    Sebastian Gottschalk, Sep 12, 2006
    #6
  7. Robert Wegner

    Moe Trin Guest

    On Tue, 12 Sep 2006, in the Usenet newsgroup alt.computer.security, in article
    <H6zNg.43989$ok5.278@dukeread01>, hdtv? wrote:

    >"Robert Wegner" <> wrote


    >> i wonder, is there a faster alternative than to overwrite a HDD n-times,
    >> if i want the data reasonably securely destroyed (without destroying the
    >> HDD itself)?


    Who is your adversary? What is your threat model? What was on the disk?

    >> I got the problem that i have 4 x 250GB HDDs which need to be erased.
    >> But with the deletion tools i know, which overwrite the whole disk
    >> n-times it takes me up to 2 days just for one of them.


    2 days = 48 hours. 250 Gigs/48 hours = 5.2 Gigs/Hr = 1.45 Megabytes/second,
    or about 4.5 Megabytes/second for a three wipe ("1's", "0's", random). That
    seems extremely slow.

    >The new DoD standard states that hdd's above 15GB can be erased with one
    >over write.


    Got a cite for that? A fast google search doesn't turn up anything recent,
    and all I can find is NISPROM. Also, what level of classification does this
    refer to? None, Confidential, Secret? Certainly anything above Secret
    requires the physical destruction of the media.

    Old guy
    Moe Trin, Sep 12, 2006
    #7
  8. Sebastian Gottschalk wrote:

    > George Orwell wrote:
    >
    > > Robert Wegner wrote:
    > >
    > >> Hi,
    > >>
    > >> i wonder, is there a faster alternative than to overwrite a HDD n-times,
    > >> if i want the data reasonably securely destroyed (without destroying the HDD
    > >> itself)?

    > >
    > > Yes. A very large magnet.

    >
    > Keeping the HDD intact doesn't mean that you're supposed to magnetize the
    > package and destroying the electronics around the plates.


    People degauss hard drives every day without destroying them, dumbass.
    And the poster clearly stated there was issues that needed to be
    addressed if doing it "down and dirty". So you're either too stupid to
    understand what you read, or to lazy to read it.

    You're also proven a liar once again because you replied to a post
    originating from a place you claimed to have killfiled. A pathetic
    liar no less, who announces plonks like a rube and then doesn't actually
    do the deed.

    Free clue Gobblesnot: You threatening to ignore someone is a joke, not
    a threat.
    Borked Pseudo Mailed, Sep 13, 2006
    #8
  9. Robert Wegner

    nemo_outis Guest

    Borked Pseudo Mailed <> wrote in
    news::

    > People degauss hard drives every day without destroying them, dumbass.



    You may wish to reconsider.

    With any modern drive a thorough degaussing would erase the servo tracks as
    well as user data and render the drive useless (the manufacturer, the only
    fellow who could realistically reestablish the servo tracks, is almost
    certainly not going to be willing to do this on a used drive. Even if he
    were willing, the cost would make it a very unappealing approach.)

    Moreover, the coercivity of the magnetic materials used in today's drives
    is so high that enormous fields have to be applied (an 8000 Oersted
    external field applied through the case is required to reliably erase
    typical 4000 Oe disk material). A field of this magnitude will mangle the
    heads and risks distorting the disks themselves.

    In short, degaussing effective enough to erase data is certain to ruin the
    drive.

    Regards,
    nemo_outis, Sep 13, 2006
    #9
  10. Robert Wegner

    nemo_outis Guest

    "nemo_outis" <> wrote in
    news:Xns983D96EB791CAabcxyzcom@127.0.0.1:

    > Borked Pseudo Mailed <> wrote in
    > news::
    >
    >> People degauss hard drives every day without destroying them,
    >> dumbass.

    >
    >
    > You may wish to reconsider.
    >
    > With any modern drive a thorough degaussing would erase the servo
    > tracks as well as user data and render the drive useless (the
    > manufacturer, the only fellow who could realistically reestablish the
    > servo tracks, is almost certainly not going to be willing to do this
    > on a used drive. Even if he were willing, the cost would make it a
    > very unappealing approach.)
    >
    > Moreover, the coercivity of the magnetic materials used in today's
    > drives is so high that enormous fields have to be applied (an 8000
    > Oersted external field applied through the case is required to
    > reliably erase typical 4000 Oe disk material). A field of this
    > magnitude will mangle the heads and risks distorting the disks
    > themselves.
    >
    > In short, degaussing effective enough to erase data is certain to ruin
    > the drive.
    >
    > Regards,
    >


    Here, as an example, is a slightly-behind-the-curve refurbished model that
    produces 4000 Oe or so and can erase hard disk media up to about 2000 Oe
    through the case. Note that the price makes even this used model
    uneconomic unless its cost can be amortized against many, many drives.

    http://www.datadev.com/ge4000.html
    nemo_outis, Sep 13, 2006
    #10
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.

Share This Page