Wiping HD

This is a discussion on Wiping HD within the Tech Board forums, part of the Community Boards category; Hi! I've read somewhere that people can read through layers and layers of data on a hard disk. So even ...

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    Wiping HD

    Hi! I've read somewhere that people can read through layers and layers of data on a hard disk. So even if you format your hard disks and write over the old clusters, someone can still read what was previously on the disk. I also read somewhere that these people can read to about 30 layers of old data on a disk. I'm sure you guys know what I'm talking about.

    How feasable would it be to write a simple program that just fills the HD up with junk data files, then formats the disk, and keeps doing that over and over and over?. I think I could write a program to do this, let it run over-night and in theory it should have been filled and formatted hundreds of times. Does anyone think this would make it impossible for someone to get old data from my HD?

    I'm building a new PC, and will definately get rid of my old one. I'd like give it away without taking a hammer to the HD's.

    Any thoughts, suggestions? Am I just being silly?

    Thanks,
    LittleJohn

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    and the hat of wrongness Salem's Avatar
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    I think if you just format it and write zeros over the whole disk a couple of times, then you're safe from everyone except the "Three Letter Agencies".

    > I also read somewhere that these people can read to about 30 layers of old data on a disk
    Seems highly theoretical to me.
    Writing data, then writing zeros 30 times, you might be able to detect a faint signal with an oscilloscope.

    Extrapolate that to being overwritten a random number of times with random bit patterns. Say your super secret file was overwritten 20 times in one sector and only 17 times in an adjacent sector. Figuring that out would be no cakewalk.
    Data recovery at that rate is going to be $'s per byte.

    The cost of attempting it needs a big potential payoff, so unless you're Osama or some billion dollar criminal mastermind, I think you're safe enough.

    Or as you say, get physical with the disk and buy a replacement - they're not that expensive.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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    Yes, my avatar is stolen anonytmouse's Avatar
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    Wouldn't it be easier just to put a very powerful magnet to the HD? You'd probably screw up the whole magnetic field around it.
    Or would it make it unusable?
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    Toaster Zach L.'s Avatar
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    The most secure way would of course be to beat your HD into very tiny little pieces with a sledge hammer, and the incinerate the remains.
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    PC Fixer-Upper Waldo2k2's Avatar
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    a criminal took serated scissors to a floppy...they still peiced it back together and nailed his a$$ (im pretty sure they didn't do any "creative interpretation" of the bits)
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    haha.. I'm just looking to keep my good name and credit clean. I don't want to donate my PC to a church, and some kid doing community service there somehow gets enough info on me to start opening credit card accounts in my name.

    A big magnet will destroy the HD. I don't really want to put more money into a PC that I'm going to get rid of. I'll just write a small program, stick it on a MS-DOS boot disk and it'll write and delete away.. I think it'll be fun and good experience for me.

    I'm not afraid of the CIA, NSA, IRS, UPS, whatever... I just don't want a $30,000 bill to arrive in the mail unexpectedly.

    Thanks everyone for your posts!

    --LittleJohn--

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    PC Fixer-Upper Waldo2k2's Avatar
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    U R STUPID

    you NEVER save your credit card number to your hard drive for ANY reason. No matter what you plan on doing with your computer.

    There's not going to be anyone at your church that can get data back from a format of the disk and install of an OS. You're safe from that, I'd be much more worried about trojans/keyloggers getting that kind of info and transmitting it over the net than some punk kid figuring out how to read your data off the drive.
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    U R STUPID

    you NEVER save your credit card number to your hard drive for ANY reason. No matter what you plan on doing with your computer.
    Please read my above post again, and learn to use proper english while attempting to insult people's intelligence.

    Opening a new account would require obtaining a new credit card number. Which means even if I did, for whatever reason, save my credit card numbers to my hard-drive, the would-be hacker opening a new account would have nothing to do with my current credit cards.

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    I have a question. What are the chances of someone actually trying to recover information from a wiped drive, and what is the difficulty of that. You guys make it sound easy, but I can't even recover my own deleted files.
    "When I die I want to pass peacefully in my sleep like my grandfather did, not screaming and yelling like the passengers in his car."

  11. #11
    and the hat of wrongness Salem's Avatar
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    To recover deleted files, all you really need is a disk editor which can read individual sectors of a disk.
    Undelete programs merely automate this process.

    To recover erased files, you need well all sorts of specialist hardware, not to mention lots of $ and time.

    But I've said this already....
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

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    PC Fixer-Upper Waldo2k2's Avatar
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    >>and learn to use proper english

    ouch that hurt...

    I don't care what your reasoning is for saving information like that on your computer, it's stupid regardless.

    If you're such an expert on what's safe to have on your computer, why'd you even ask this question in the first place?
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