How secur is delete/erase ? - VMS

This is a discussion on How secur is delete/erase ? - VMS ; Hello, i hope, i have a very simply question. How secur is "delete/erase" ? After this command, no other program can recover these informations? Thank you very much! Klaus...

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Thread: How secur is delete/erase ?

  1. How secur is delete/erase ?

    Hello,

    i hope, i have a very simply question.

    How secur is "delete/erase" ? After this command, no other program can
    recover these informations?

    Thank you very much!

    Klaus



  2. Re: How secur is delete/erase ?

    DELETE/ERASE by default writes one pass of zeros. There are documented
    ways to change this to write a different pattern or have more passes.

    Another tool built in to VMS is
    ANALYZE/ MEDIA/EXER=FULL
    which will perform three passes - zeros, ones and random.

    It's up to you how far you want to go with this. Some would say that
    is ok, others would call for physical destruction of the disk and all
    who have seen it.

  3. Re: How secur is delete/erase ?

    Thank you.

    Could you give me a short hint where is that documented to change the
    pattern ?

    Klaus

    "IanMiller" schrieb im Newsbeitrag
    news:eec075ed-2586-49cd-b22d-35896ed76547@59g2000hsb.googlegroups.com...
    > DELETE/ERASE by default writes one pass of zeros. There are documented
    > ways to change this to write a different pattern or have more passes.
    >
    > Another tool built in to VMS is
    > ANALYZE/ MEDIA/EXER=FULL
    > which will perform three passes - zeros, ones and random.
    >
    > It's up to you how far you want to go with this. Some would say that
    > is ok, others would call for physical destruction of the disk and all
    > who have seen it.




  4. Re: How secur is delete/erase ?

    In article <483c3795$0$9740$9b622d9e@news.freenet.de>, "Klaus-D. Bohn" writes:
    >Thank you.
    >
    >Could you give me a short hint where is that documented to change the
    >pattern ?
    >
    >Klaus


    For starters:

    http://h71000.www7.hp.com/doc/82FINA...41pro_091.html

    --
    VAXman- A Bored Certified VMS Kernel Mode Hacker VAXman(at)TMESIS(dot)COM

    "Well my son, life is like a beanstalk, isn't it?"

    http://tmesis.com/drat.html

  5. Re: How secur is delete/erase ?

    Klaus-D. Bohn wrote:
    > Hello,
    >
    > i hope, i have a very simply question.
    >
    > How secur is "delete/erase" ? After this command, no other program can
    > recover these informations?
    >
    > Thank you very much!
    >
    > Klaus
    >
    >


    Nothing on your VMS system will ever read that information. If someone
    got his hands on your disk and had unlimited resources, it is possible
    that some information could be recovered. The only way to be certain
    that no one will EVER read your data from that disk is to destroy the
    media! If you are not protecting information classified "burn before
    reading" DELETE /ERASE is probably sufficient.

  6. Re: How secur is delete/erase ?

    In article <483c2cbc$0$1515$9b622d9e@news.freenet.de>, "Klaus-D. Bohn" writes:
    > Hello,
    >
    > i hope, i have a very simply question.
    >
    > How secur is "delete/erase" ? After this command, no other program can
    > recover these informations?


    That's the idea. I use anywhere I want to make sure no one else
    can recover the data. The erase algorithm uses what was at one
    time a "DoD approved" pattern (what it was approved for, I don't
    know). I've used it for old VAXen that were being excessed to
    make sure no sensitive or licensed data remained on the drives.

    That said, there may be data in blocks that went bad and were
    revectored that is physically possible to restore. And as a disk
    runs it's seek head position varies slightly so that it is possible
    that the some data can be recovered from shadows of old tracks.

    This is not as perfect as deguassing the media, but generally leaves
    the drive still useable without needing a low level format.

    And often in DoD, you have to run the drive through a shredder to
    meet requirements.


  7. Re: How secur is delete/erase ?

    On May 27, 11:45 am, "Klaus-D. Bohn" wrote:
    > Hello,
    >
    > i hope, i have a very simply question.
    >
    > How secur is "delete/erase" ? After this command, no other program can
    > recover these informations?
    >
    > Thank you very much!
    >
    > Klaus


    Klaus,

    I do not have the citation at hand, but there are US DoD standards for
    the erasure of media (I am sure that there are NATO equivalents).

    The OpenVMS erase (even without alternate passes/patterns) is
    generally sufficient to block programmatic reads.

    If whomever is trying to read the data has far more substantial
    resources, there are still a variety of ways that some data can be
    compromised. Among these problematic areas are a) bad blocks that
    formerly contained data; and b) if the disk is overwritten with a
    fixed pattern, there are reports that the original data can
    potentially recovered by lab-grade procedures. If this is of interest,
    I would refer you to the appropriate research.

    - Bob Gezelter, http://www.rlgsc.com

  8. Re: How secur is delete/erase ?

    One technique I've been unofficially told is used by the Canadian
    Armed Forces to ensure permanent erasure of scrapped hard drives:

    - Remove platters from drives
    - Belt sander applied to recording surfaces

    I would supplementally suggest using a dust mask and eye protection.

  9. Re: How secur is delete/erase ?

    On Tue, Jun 10, 2008 at 05:27:47AM -0700, Rod wrote:
    > One technique I've been unofficially told is used by the Canadian
    > Armed Forces to ensure permanent erasure of scrapped hard drives:
    >
    > - Remove platters from drives
    > - Belt sander applied to recording surfaces
    >
    > I would supplementally suggest using a dust mask and eye protection.


    that's a bit extreme..
    why not just cook the platters. Probably heating the drives to 400oC or so
    would do the job. Very cheap and very little manual labour.

    --
    Anton Shterenlikht
    Room 2.6, Queen's Building
    Mech Eng Dept
    Bristol University
    University Walk, Bristol BS8 1TR, UK
    Tel: +44 (0)117 928 8233
    Fax: +44 (0)117 929 4423

  10. Re: How secure is delete/erase ?

    That's nothing, the US Military had a manual written on how to blow up a
    Leica M4 should you crash in foriegn soil. And I am sure the VAX in the F15
    aircraft were positioned in a way that if the pilot ejected, they would be
    destroyed.


    "Rod" wrote in message
    news:c7de465b-fab2-41b3-8ae2-2489f4f50a12@79g2000hsk.googlegroups.com...
    > One technique I've been unofficially told is used by the Canadian
    > Armed Forces to ensure permanent erasure of scrapped hard drives:
    >
    > - Remove platters from drives
    > - Belt sander applied to recording surfaces
    >
    > I would supplementally suggest using a dust mask and eye protection.




  11. Re: How secur is delete/erase ?

    Rod wrote:
    > One technique I've been unofficially told is used by the Canadian
    > Armed Forces to ensure permanent erasure of scrapped hard drives:
    >
    > - Remove platters from drives
    > - Belt sander applied to recording surfaces
    >
    > I would supplementally suggest using a dust mask and eye protection.


    Another technique I heard at a previous job involved melting the
    platters, mixing them with radioactive material, and burying the
    resulting slag. True? I don't know. Given some the information that
    may have been on those platters? wouldn't surprise me.

    --
    John Reagan
    OpenVMS Pascal/Macro-32 Project Leader
    Hewlett-Packard Company

  12. Re: How secur is delete/erase ?

    On Jun 10, 8:51 am, Anton Shterenlikht wrote:
    > On Tue, Jun 10, 2008 at 05:27:47AM -0700, Rod wrote:
    > > One technique I've been unofficially told is used by the Canadian
    > > Armed Forces to ensure permanent erasure of scrapped hard drives:

    >
    > > - Remove platters from drives
    > > - Belt sander applied to recording surfaces

    >
    > > I would supplementally suggest using a dust mask and eye protection.

    >
    > that's a bit extreme..
    > why not just cook the platters. Probably heating the drives to 400oC or so
    > would do the job. Very cheap and very little manual labour.


    The necessary temperature is a physical property of the magnetic
    medium, the Curie Temperature. If you get all of any sample of any
    permanently magnetizable material above its Curie Temperature, no
    matter for how short a time, and then cool it, the resulting state is
    randomized, with zero retained information from the original state.
    This quantum mechanical effect provides a sure and certain erasure,
    beyond any possibility of recovery, provided only that you know what
    the Curie Temperature is, and that you bake it long enough to get the
    entire sample above it. Setting your oven hotter just reduces the time
    you need to bake it, in order to be sure that the coldest part is warm
    enough.

    I have no idea what the Curie Temperature is for the recording medium
    on modern disk drives, nor whether any modern disk drive's other
    components will survive such a high temperature excursion. I do not
    expect that they would.

    >
    > --
    > Anton Shterenlikht
    > Room 2.6, Queen's Building
    > Mech Eng Dept
    > Bristol University
    > University Walk, Bristol BS8 1TR, UK
    > Tel: +44 (0)117 928 8233
    > Fax: +44 (0)117 929 4423



  13. Re: How secur is delete/erase ?

    In article , Rod writes:
    > One technique I've been unofficially told is used by the Canadian
    > Armed Forces to ensure permanent erasure of scrapped hard drives:
    >
    > - Remove platters from drives
    > - Belt sander applied to recording surfaces
    >
    > I would supplementally suggest using a dust mask and eye protection.


    Unofficially, but often mentioned, the US DoD supposedly uses
    sledgehammers.

    If they can't get enough sledgehammers in Canada, perhaps they
    could just remove the spindle and enter it into a Curling match.


  14. Re: How secur is delete/erase ?

    In article <2ec3b455-f146-4149-af3d-2160c3f156ef@m45g2000hsb.googlegroups.com>, rdpiccard@gmail.com writes:
    >On Jun 10, 8:51 am, Anton Shterenlikht wrote:
    >> On Tue, Jun 10, 2008 at 05:27:47AM -0700, Rod wrote:
    >> > One technique I've been unofficially told is used by the Canadian
    >> > Armed Forces to ensure permanent erasure of scrapped hard drives:

    >>
    >> > - Remove platters from drives
    >> > - Belt sander applied to recording surfaces

    >>
    >> > I would supplementally suggest using a dust mask and eye protection.

    >>
    >> that's a bit extreme..
    >> why not just cook the platters. Probably heating the drives to 400oC or so
    >> would do the job. Very cheap and very little manual labour.

    >
    >The necessary temperature is a physical property of the magnetic
    >medium, the Curie Temperature. If you get all of any sample of any
    >permanently magnetizable material above its Curie Temperature, no
    >matter for how short a time, and then cool it, the resulting state is
    >randomized, with zero retained information from the original state.
    >This quantum mechanical effect provides a sure and certain erasure,
    >beyond any possibility of recovery, provided only that you know what
    >the Curie Temperature is, and that you bake it long enough to get the
    >entire sample above it. Setting your oven hotter just reduces the time
    >you need to bake it, in order to be sure that the coldest part is warm
    >enough.
    >
    >I have no idea what the Curie Temperature is for the recording medium
    >on modern disk drives, nor whether any modern disk drive's other
    >components will survive such a high temperature excursion. I do not
    >expect that they would.


    Now you've made me Temperature Curie-ous.

    --
    VAXman- A Bored Certified VMS Kernel Mode Hacker VAXman(at)TMESIS(dot)COM

    "Well my son, life is like a beanstalk, isn't it?"

    http://tmesis.com/drat.html

  15. Re: How secur is delete/erase ?

    In article <4qbPlsaZBjXM@eisner.encompasserve.org>, koehler@eisner.nospam.encompasserve.org (Bob Koehler) writes:
    >In article , Rod writes:
    >> One technique I've been unofficially told is used by the Canadian
    >> Armed Forces to ensure permanent erasure of scrapped hard drives:
    >>
    >> - Remove platters from drives
    >> - Belt sander applied to recording surfaces
    >>
    >> I would supplementally suggest using a dust mask and eye protection.

    >
    > Unofficially, but often mentioned, the US DoD supposedly uses
    > sledgehammers.


    Would those be the $700.00 or $7,000.00 sledgehammers?

    --
    VAXman- A Bored Certified VMS Kernel Mode Hacker VAXman(at)TMESIS(dot)COM

    "Well my son, life is like a beanstalk, isn't it?"

    http://tmesis.com/drat.html

  16. Re: How secur is delete/erase ?

    In article <484efd78$0$11606$607ed4bc@cv.net>, VAXman- @SendSpamHere.ORG writes:
    >
    > Would those be the $700.00 or $7,000.00 sledgehammers?
    >


    Depends on who's doing the purchasing. I've actually worked with
    government personnel who know how to buy hammers from hardare stores.


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