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A New Technique to Quickly Erase Hard Drives 458

Posted by CowboyNeal
from the clean-and-clear dept.
RockDoctor writes "Stories about 'wiped' hard drives appearing on eBay (and other channels) and being stuffed with personably-identifiable data are legion; rarer are spy planes having to land on enemy territory, but it happened in 2001 to a US spy plane over an un-declared enemy (China, and that's a topic in itself). Dark Reading reports the development of a technique to securely wipe a hard drive in seconds, and which is safe for flying. (The safe for flying criterion rules out things like fun with packing the drives in thermite. Also thermiting the drives may not erase the platters to the standard required, which is moderately interesting itself."
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A New Technique to Quickly Erase Hard Drives

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  • by Anonymous Coward on Saturday June 17, 2006 @11:48AM (#15554916)
    can be rendered inoperable in seconds - the method's name is "slashdotting".
     
    How curious that the anti-bot please-type-in-this-word word is kilobyte for this post.
  • Joe does it (Score:5, Interesting)

    by janet-on (982800) on Saturday June 17, 2006 @11:48AM (#15554918)
    Unfortunately a few passes with random data is not as effective against a sophisticated recovery effort as is often assumed.
    Now if it's just some random joe with an undelete program he got for $19.99 at the local shop then a single pass is often enough, more sophisticated software only tools might get past a few, but with hardware equipment (probably not used often below the fbi/pro forensics places) you might want to do something a bit more secure.
    With good knowledge of how the data is actually stored on the disk you can figure out patterns that tend to degausse the bits being wiped and help eleminate the residual images left by the micro imperfection in head positioning (which are shrinking to almost nothing these days) and simular effects a trully sophisticated data recovery effort might use.

    Peter Gutman put out a paper about this that can be read at http://www.cs.auckland.ac.nz/~pgut001/pubs/secure_ del.html [auckland.ac.nz]
    that explains it better.
    Though with remapping and newer recording techniques things change and software only erasure becomes more and more problematic. At the highest levels of secrecy I believe most governments require over-kill levels of outright hardware destruction.
    • by r00t (33219) on Saturday June 17, 2006 @12:04PM (#15554989) Journal
      Normally the hard drives just go into a grinder or furnace. Sure, that won't suit an airplane, but neither will a bulky magnetic device that weighs 125 pounds per hard drive. (can't just have one because the drive has to slide right in)

      The obvious solution: encrypt everything that hits the disk, keep the key in RAM, and overwrite the key when needed.

      I'd worry the most about antenna shapes and sizes and various analog circuitry.
      • by NixieBunny (859050) on Saturday June 17, 2006 @12:56PM (#15555156) Homepage
        With all due respect, the article doesn't describe the device as you say. It weighs 125 lbs in prototype form, which will be reduced for production, and there's only one needed per airplane, not one per drive. What they're proposing is much less bulky than a similarly useful grinder or furnace. After all, it has to be usable on many packaged drives, quickly, in emergency plane-crash conditions. In a previous life, I did some work for E-Systems on a spy plane (Rivet Joint) using big removable ESDI drives of a few hundred megabytes each capacity, and the project guy said that it took about 20 minutes for their emergency drive erase sequence to finish. Not good if you're going down in enemy airspace!
        • Sure, they say they will get the weight down. OK, maybe they cut it in half.

          They do need one device per drive. You missed the part about the drive being automatically pulled into the device, and the part about a twist handle as a backup.

          In other words, this is a drive enclosure. The drive sits in the safe part of the enclosure most of the time, connected to a destruction actuator. Nobody is going to be running around the airplane yanking out drives.

          Probably a few drives could go into a mechanically complica
          • Think of a flying datacenter with rackmount systems from a variety of different vendors

            A variety of different vendors that all have to meet a spec, namely that the drive must be mounted in a non-metallic carrier of such-and-such dimensions. Or just specify that each drive must be mounted in a "Type SZW data carrier", and it's up to the primary contractor (who also supplies the SZWs) to make it all work. Either way, it's all pretty trivial: the Navy wants one of these mega-erasers for its P-3s, so (say) Lo

          • They do need one device per drive. You missed the part about the drive being automatically pulled into the device

            The six disc CD changer in my car pulls CDs automatically into one device. I'm sure this technology will never progress to such an advanced stage though.
             
      • by Anonymous Coward on Saturday June 17, 2006 @02:30PM (#15555494)
        You might be glossing over the flight critical requirement though. "Keep the key in RAM" is likely not something that would be allowed.. or incredibly hard to get certified. Would have to prove (which is harder than just showing) that while in flight, there was no way the key could get lost, or changed, or ... such that the software could get locked down in flight. I don't think that it would be impossible, just that the hoops you might have to go through may make other options more attractive.

        I work on UAV's, so we have to care about this a lot.

        Check out some of the standards:
        DO-178B [wikipedia.org]
        Or STANAG 4044, but I don't have a good link.
      • by FluffyG (692458) on Saturday June 17, 2006 @06:21PM (#15556217)
        I'm a LAN integrator for a mobile military communications system that is used for passing of secret and top secret material... Our manual says it takes about 3 grenades in the hummer to format all the hard drives if they need to do it quickly :)
      • by AJWM (19027) on Sunday June 18, 2006 @02:02AM (#15557385) Homepage
        I'd worry the most about antenna shapes and sizes and various analog circuitry.

        My parents worked at (met at) a secret radar research site (the misleadingly named TRE - Telecommunications Research Establishment) during WW-II. My mom once mentioned that since it was known that in case of lost aircraft there was a real danger of some of the equipment falling into enemy hands, it was routine practise to include dummy circuitry and sometimes wholly bogus equipment just to add to the confusion. Sometimes such equipment was deliberately allowed to be "captured".

        A slight weight penalty, but deemed worth it.

    • Re:Joe does it (Score:5, Insightful)

      by Anonymous Coward on Saturday June 17, 2006 @12:36PM (#15555087)
      That is mostly urban legend. There is a theoretical possibility that overwritten data could be reconstructed, even several layers "deep", but in practice there is no commercially available service capable of that stunt. If you know of one, name it (with references that they can do it). If they could do it, they would have to have technology available which could instantly multiply the space on these platters. It's not just a matter of having a reader with twice as good a SNR as a standard RW head. The writing harddisk doesn't just add signal, it also adds noise. The SNR on the platter will be barely good enough to read the signal of the last write. Otherwise the harddisk manufacturer could have made a bigger harddisk at the same price. The economics of the situation make recovering a previous write unlikely. The real problem with deletion by overwriting data is that it is really slow. It takes hours per disk.

      Instead of worrying about residual magnetism which can at best be detected by government agencies with extreme funding, people should simply never write unencrypted confidential information anywhere. This also protects you in cases where you didn't schedule the removal of a harddisk, i.e. theft.
    • Wrong (Score:5, Informative)

      by bwd (936324) on Saturday June 17, 2006 @12:45PM (#15555123) Homepage
      The paper you are quoting from is horribly out of date and very little of that applies to modern drives. This post [slashdot.org] does a good job of explaining Gutmann's more recent comments.

      Plus, some people have called into question a lot of the sources used in that paper. It seems that some of the sources don't even exist.

    • Re:Joe does it (Score:3, Insightful)

      by Anonymous Coward
      Threat is combination of assets and risks. The amount of risk is often a funtion of the value, or percieved value, of the assets, but that generality is proved invalid when bored kids are involved, or the attack is particularly simple.

      In term of data on hard disk, there are three circumstances. First, a person may not protect the asset, i.e. not erase the hard disk, and a bored kid then rummages throughthe harddisk. Second, a user may not understand what erase means. There was a time when erase simple

    • Re:Joe does it (Score:5, Informative)

      by gweihir (88907) on Saturday June 17, 2006 @01:26PM (#15555247)
      Now if it's just some random joe with an undelete program he got for $19.99 at the local shop then a single pass is often enough, more sophisticated software only tools might get past a few,

      Let me correct that: There is no way in this universe software can recover anything from a disk overwritten once with zeros. It is fundamentally impossible.

      Also to Peter Gutman's paper: It is still relevant, but the technology has changed. Gutman is very relevant for things like floppy disks (that can hold 100MB, but are used only for 2MB). But todays HDDs go so close to the limits of the amount of data that can be physically present on a disk (as dictated by S/N ratio and surface area), that even a single overwrite with random data may be completely unrecoverable with any technology. Nobody really knows.
      • Re:Joe does it (Score:3, Insightful)

        by Mr. Freeman (933986)
        Actually, people do know. They've tried it and it works. People have been able to recover data up to something like 2-4 overwrites and it's theoretically possible up to something like 5-7. However I believe this "theoretical" limit requires millions of dollars in technology.
      • Re:Joe does it (Score:3, Informative)

        by DamnStupidElf (649844)
        Let me correct that: There is no way in this universe software can recover anything from a disk overwritten once with zeros. It is fundamentally impossible.

        That depends on how much attackers know about a given drive. If they can rewrite the drive firmware to give raw access to disk tracks and sub-track positioning, there's a lot that can be done in software without opening the drive.

        But todays HDDs go so close to the limits of the amount of data that can be physically present on a disk (as dictated by
  • by UnknowingFool (672806) on Saturday June 17, 2006 @11:50AM (#15554927)

    Dozens of prank hard drive erasing have occurred within the Georgia Institute of Technology's nerd population. This was preceded by large orders of extremely powerful magnets. When questioned, the victims only had this to say:
    "Khaaaaaaaaaaaaaaaaaaaaaaan!"

  • by Adult film producer (866485) <van@i2pmail.org> on Saturday June 17, 2006 @11:50AM (#15554931)
    When I need to protect my data from spying eyes I secure a 500m sata cable into the back port and slowly, very carefully; feed the hard drive into the event horizon. Giving it a good yank after a few minutes and reeling it back in.. the drive returns to normal working condition afterwards.
  • First question: (Score:5, Insightful)

    by fluch (126140) on Saturday June 17, 2006 @11:51AM (#15554935)
    Why wasn't the content of the harddrive encrypted?
    • The performance of full-disk encryption tools probably wasn't adequate at the time.
    • Re:First question: (Score:2, Interesting)

      by nottestuser (166818)
      Because the Windows 98 computers running the spy cameras don't support encrypted file systems.

      Seriously, this is a fricking no-brainer. Make the key 4096 bits of random data, load it into battery-backed RAM from a storage device kept at the air field. When you run in to a problem you have 4K of data in RAM to destroy instead of GBs of data on disk with the added benefit that if you ever get the disk back to the air field you still get your data. Unless the Air Force doesn't have access to unbreakable encryp
      • Why not just stream the video/photos in real-time to a satellite (encrypted of course) and not even worry about losing your data if the plane crashes? I imagine that's what the Predator drones do.
        • Re:First question: (Score:3, Insightful)

          by bwd (936324)
          I would imagine that the plane was recording enormous amounts of data, both video and otherwise. Streaming all of that to a satellite in real time would not be practical. I'm sure that those large spyplanes were recording significantly more data than a predator drone.
    • Re:First question: (Score:3, Insightful)

      by SagSaw (219314)
      Why wasn't the content of the harddrive encrypted?

      Encrypting the harddrive (which it may have been) simply changes the problem from one where you need to destroy the unencrypted information quickly and compleatly to one where you need to destroy the encryption key quickly and compleatly. Destroying the key may or may not be any easier that destroying the data depending on how it is stored. Also, even if the data is encrypted and the key compleatly destroyed, you probably still want do destroy the encr
  • ...stuffed with personably-identifiable data are legion...


    I think the word that should be there is legend. Or am I just unaware of another definition of legion?
  • by Anonymous Coward on Saturday June 17, 2006 @11:54AM (#15554949)
    Just use Maxtor harddisk drives, those things destroy themselves all the time!
  • by Richard_J_N (631241) on Saturday June 17, 2006 @11:57AM (#15554958)
    Wouldn't it be easier to use a flash memory chip? It's unlikely that more than a few GB would be needed. And destroying a flash chip is much easier.
    Or, just encrypt the data with the key in RAM. (Linux can already do this with swap - it's completely transparent to the user, and the key only lasts as long as the system remains running).
  • What a crock... (Score:5, Interesting)

    by Anonymous Coward on Saturday June 17, 2006 @11:58AM (#15554965)
    The Chinese eventually gained access to U.S. military secrets.

    What a crock of crap. That and the rest of the story.

    I worked in the military long enough to know that they would have encrypted sensitive data as a requirement (destroy or erase a security token, in the use of a combined token/passphrase crypto system and the data is safe) and that the military already use storage devices which can be erased in seconds with a function specifically built just for that.

    This story sounds like it is just trying to inject some life into the stock price of some crap company that provides too little, too late.
    • Re:What a crock... (Score:4, Insightful)

      by LWATCDR (28044) on Saturday June 17, 2006 @12:27PM (#15555071) Homepage Journal
      You forgot that the plane wasn't over China but was in international airspace when it got hit by the Chinese jet. You got to love the Chinese claim that a 1950's turbo-prop airliner managed to ram a supersonic jet fighter.
      Those guys are a laugh riot.
  • why not store the entire filesystem on RAM with a battery, in a tmpfs. when you want to wipe it, put a thousand volts through it for a couple of seconds, then cut power?
    • "why not store the entire filesystem on RAM with a battery, in a tmpfs. when you want to wipe it, put a thousand volts through it for a couple of seconds, then cut power?"

      RAM has the same problem. If a bit has been set a particular way for a long time, it will have detectable effects afterwards. It's not enough for your computer to be able to suspend to RAM without power to maintain the memory, but a forensics lab would have better luck recovering the data.
    • War planes are supposed to fly in ... well, war. And in war, people shoot at you. Now, if you happen to live in an area where brownouts happen, you know what even a minimal power outage does to your system. The data on the HD, however, stays ok. So, during a stress situation where power fails for a moment, the plane system may be shot, but it can notice this and reboot to a stable state (this is done by MAGNITUDES faster than on your Windows box, btw). This is not an option if the system itself is stored in
  • by Sosarian (39969) on Saturday June 17, 2006 @11:59AM (#15554971) Homepage
    If this isn't a fluff piece I don't know what is.

    "We developed a 125 rare earth magnetic eraser with self contained power source"

    Interesting, but adding in this US spy plane angle has got to be simply PR.
  • I know by itself thermite and similar methods have difficulty penetrating the outer case reliably, but I would think drill+thermite injection to fill the internal cavity of the system would be effective..

    Combined with an encryption scheme I would think it virtually impossilbe to recover data if you can reduce the platters to slag reliably..
    • Re:Drill+Thermite? (Score:3, Interesting)

      by Oggust (526634)

      I know by itself thermite and similar methods have difficulty penetrating the outer case reliably, but I would think drill+thermite injection to fill the internal cavity of the system would be effective..

      Takes too long to drill the disks and insert the thermite, while your spy plane is spiralling down.

      And anyway, if the themite didn't fully destroy the disks [chalmers.se], you weren't using enough [chalmers.se] of it. See? [chalmers.se]

      /August.

  • Erasing, not Voodoo (Score:5, Interesting)

    by Psionicist (561330) on Saturday June 17, 2006 @12:00PM (#15554978)
    I would like to take the oppertunity here to debunk a very common myth regarding hard drive erasure.

    You DO NOT have to overwrite a file 35 times to be "safe". This number originates from a misunderstanding of a paper [auckland.ac.nz] about secure file erasure, written by Gutmann.

    The 35 patterns/passes in the table in the paper are for all different hard disk encodings used in the 90:s. A single drive only use one type of encoding, so the extra passes for another encoding has no effect at all. The 35 passes are maybe useful for drives where the encoding is unknown though.

    For new 2000-era drives, simply overwriting with random bytes is sufficient.

    Here's an epilogue by Gutmann for the original paper:

    Epilogue In the time since this paper was published, some people have treated the 35-pass overwrite technique described in it more as a kind of voodoo incantation to banish evil spirits than the result of a technical analysis of drive encoding techniques. As a result, they advocate applying the voodoo to PRML and EPRML drives even though it will have no more effect than a simple scrubbing with random data. In fact performing the full 35-pass overwrite is pointless for any drive since it targets a blend of scenarios involving all types of (normally-used) encoding technology, which covers everything back to 30+-year-old MFM methods (if you don't understand that statement, re-read the paper). 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.

    Looking at this from the other point of view, with the ever-increasing data density on disk platters and a corresponding reduction in feature size and use of exotic techniques to record data on the medium, it's unlikely that anything can be recovered from any recent drive except perhaps one or two levels via basic error-cancelling techniques. In particular the the drives in use at the time that this paper was originally written have mostly fallen out of use, so the methods that applied specifically to the older, lower-density technology don't apply any more. Conversely, with modern high-density drives, even if you've got 10KB of sensitive data on a drive and can't erase it with 100% certainty, the chances of an adversary being able to find the erased traces of that 10KB in 80GB of other erased traces are close to zero.
    • If data can be recovered after fewer wipes, the people capable of recovering it certainly wouldn't advertise the fact. Extra passes are cheap, the costs of someone recovering data might not be.

      Of course, the bad sectors that get transparently reallocated leave dead sectors that can probably be recovered and would not be wiped with stock firmware, so it's academic anyway. If you can't take that risk, you have to turn the media inside the drive into molten slag. There's no other way.
    • Not to mention that the whole "residuum magnetism" that may actually have existed in 90s HDs isnt simply possible anymore with todays track density. Any kind of remnand from the last state would be well under the paramangetic limit and completely replaced by thermal noise.
      • by asuffield (111848) <asuffield@suffields.me.uk> on Saturday June 17, 2006 @01:30PM (#15555263)
        Not to mention that the whole "residuum magnetism" that may actually have existed in 90s HDs isnt simply possible anymore with todays track density. Any kind of remnand from the last state would be well under the paramangetic limit and completely replaced by thermal noise.

        That may be true at some point in the future but it currently is not, and won't be without radical changes in the storage method. There must be a certain amount of tolerance in the current systems in order to compensate for drifting effects. The problem is that if you magnetise a surface such that there are two fields with opposing polarities next to each other, they will over time drift together and kinda-sorta cancel each other out (or at least, you will no longer be able to tell which one was where). So that hard drives keep their data for some number of years, the fields have to be sufficiently strong and spaced out for the drive head to still be able to identify them after they have sat there for a year. That means the head is writing strong, clear fields, and then after a few months it reads back a weaker, fuzzier field.

        Now, if the head then writes a strong, clear field over the top of the fuzzy one... then there will be residual traces of the fuzziness in the space between the clear fields. Forensic analysis can use a far more expensive and accurate device to read the fields, and so it can spot several generations of this stuff - it's like a buildup of sediment.

        That's not the only possible technique (I don't know which one the professional data recovery companies use), but it's one that drives based around the current methods will always suffer, simply because they must have those tolerances. You can't build a drive where the residuals are completely unreadable, because it means your data will be unreadable after a few months - you have to allow enough for the data to be readable, and that means that residuals can be readable too. Anywhere that you have tolerances like this, you can build a device with a finer tolerance and discover more data.
        • That sounds nice and all, in theory. But I doubt anyone has ever recovered a file reading residual magnetic fields. Seriously! Just how DO you determain what group of bit/bytes belongs to what generation of residual fields? If you don't know what generation the bits are found on, then threading the data back togeather is meaningless. All you will get is random binary noise.
    • by asuffield (111848) <asuffield@suffields.me.uk> on Saturday June 17, 2006 @12:56PM (#15555154)
      For new 2000-era drives, simply overwriting with random bytes is sufficient.

      That's not what the text you quoted said, nor is it correct. It's true that overwriting 35 times doesn't accomplish anything more, though. The quote said:

      For any modern PRML/EPRML drive, a few passes of random scrubbing is the best you can do.


      For new 2000-era drives, simply overwriting with random bytes is the best you can do [from software / without breaking the drive]. That's because the firmware makes it almost impossible to 'securely' erase data from the drives, so you just can't do any better. It's nowhere near 'sufficient'; in fact it's almost useless against any modern hardware analysis. (The best you can do, if you don't want to keep the drive, is to heat the platters until they melt; that is guaranteed to destroy the data, but almost everything else isn't).

      The other important part of the quote is:

      Conversely, with modern high-density drives, even if you've got 10KB of sensitive data on a drive and can't erase it with 100% certainty, the chances of an adversary being able to find the erased traces of that 10KB in 80GB of other erased traces are close to zero.


      This is true, but more commonly you've got several Gb of sensitive data, and the 'enemy' manages to recover some percentage of it. There are companies who do this stuff on the open market - you send them your drive, pay a figure on the order of several thousand dollars, and a while later they send you back most of your data. Their customers tend to be law enforcement, divorce lawyers, private detectives, and companies who are big enough to afford it but not big enough to have a proper backup system in place for their laptop hard drives. They don't need to recover 100% of the porn that has been in your browser cache, just a few pages from some of the sites.
    • If I'm getting paid by the hour, 35 passes is fine by me, and I will watch every single one of them to make sure it really ran. Can't cut corners when it counts.
  • DMCA! (Score:5, Funny)

    by fluch (126140) on Saturday June 17, 2006 @12:02PM (#15554983)
    Seal the HD with a sticker that says reading the content of this HD is prohibited by the Digital Millennium Copyright Act. That will show them! :)
  • by JanneM (7445) on Saturday June 17, 2006 @12:03PM (#15554988) Homepage
    If thermite doesn't do a good job, go one better and make the platters out of thermite. Make the motor axle out of magnesium, add a fuse and you're set.

    If the burning is a problem, just make the platters from cheddar cheese, and add a mouse in a cage adjacent to the drive. Open the hatch, and problem is solved.
    • That's a good idea.... until you pull 5 Gs trying to avoid an enemy fighter and kill the mouse.

      Equip the mouse with a flight suit though, and you're all set.
    • by modecx (130548)
      I think the better solution would be to make the drive platters out of a thermite-cheddar composite. Once the mice eat the cheese we can then ignite the mice for maximum data security.
  • Not really new (Score:3, Interesting)

    by Dolphinzilla (199489) on Saturday June 17, 2006 @12:16PM (#15555033) Journal
    Both M-Systems and Memtech have solid state disk drives that implement NSA and NISPOM approved methods for secure hard drive erase - and they can erase the entire drive in under a minute -
  • by dpbsmith (263124) on Saturday June 17, 2006 @12:17PM (#15555036) Homepage
    And in further news, Georgia Tech scientists have designed a printer with an integral shredder that shreds all output continuously as it is printed.

    They have also designed a novel camera which, instead of a digital CCD array, uses a tough, thin strip of polyester polymer coated with a chemical, light-sensitive substrate. Intended for spy applications, if caught the captured images can be destroyed in seconds simply by opening the back of the camera.
  • Store the data on the disk encrypted and the key in RAM. In case of emergency erase the chip and the data becomes worthless. I wouldn't trust a system that has to operate or where the pilot has to be conscious.
    But if you're on a spy plane, wouldn't you have the enemies military secrets?
  • the researchers designed a neodymium iron-boron magnet with special pole pieces made of esoteric cobalt alloys.
    Sounds like the magnet may be worth more than the secret information it is supposed to protect.
  • Wiping disks... (Score:3, Informative)

    by Gordonjcp (186804) on Saturday June 17, 2006 @12:28PM (#15555072) Homepage
    ... by overwriting twice with random data will destroy any data beyond recovery. You can't use special things to read residual magnetic data off the platters, unless you're habitually using 25-year-old hard disks. Modern drives use very complicated modulation schemes, unlike old MFM drives.
  • by MrP- (45616) <rob@elitemr p . n et> on Saturday June 17, 2006 @12:29PM (#15555074) Homepage
    Like this one [elitemrp.net] from my work last week.

    (nothing important was on it though)
  • DRM (Score:3, Funny)

    by elgee (308600) on Saturday June 17, 2006 @12:38PM (#15555098)
    Now the RIAA/MPAA/FUD are going to demand that such a device be put into every possible digital recording device.

    Attempt to copy a protected product and BAM, your hard drive is toast.
  • They used a magnetic force microscope to map even the smallest magnetic domains on the surface of an erased disk drive to ensure that the patterns found there were completely random.

    So after they passed the test drive through a very strong magnetic field the data was random? Wouldn't it be in a pattern to match the field??
  • by vadim_t (324782) on Saturday June 17, 2006 @12:59PM (#15555165) Homepage
    Now, even assuming there's something remaining after thermite, how do you get it out of a molten platter? The head hovers at nanometers from the disk's surface. A bent disk with a huge hole through it will just instantly wreck any head trying to read it. Is it even technically possible to restore the platter to a condition where you can even try to read anything from it?

    Besides, shouldn't all the data vanish due to the reaction bringing the surface above the Curie temperature?
  • Sounds fishy to me (Score:5, Insightful)

    by gweihir (88907) on Saturday June 17, 2006 @01:04PM (#15555178)
    Degaussers are nothing new. But there is no need to use them. Encryption does the trick as well. Just erase the key securely and you are done. If the device that the disk is installed in does not support encryption, then develop a module that sits between disk and device and encrypt on that. Attach a switch that triggers key erasure.

    There is a second problem with degaussers: You have to physically remove the disks from their housing. That may take more than minutes.

    And there is a third problem with degaussers: You have to very carefully check they work with each device they are to be used on. For example, older degaussers do fine for older disks, but are completely useless for modern ones.

    And a 4th problem: Degaussers do not work at all for solid-state disks. Since they are not that uncommon in military application and actually may look the same, that seems to be a serious problem. One that encryption does not have.

    I see one advantage for the permanent-magnet solution in military application: It works without power. But if you use the encryption-in-the-cable approach I described above, you can keep the key in a battery-buffered memory chip and erase that securely using the power of the battery (not quite as simple as it sounds, but it is possible to do). All in all, this mainly seems to be a scheme to sell the military something expensive.
     
  • correction (Score:3, Insightful)

    by slashdotnickname (882178) on Saturday June 17, 2006 @01:14PM (#15555210)
    it happened in 2001 to a US spy plane over an un-declared enemy (China, and that's a topic in itself).

    This is offtopic, although a more interesting topic than "wiping data", but the plane itself was over international waters and never over China's territory.

    Also, since when does spying require a declaration of war? The whole point of spying is to aid in deciding-the-need-for or course-of preemptive actions. Given the Chinese government's penchant for secrecy and censorship, it seems fair to want to keep an eye on them. The same point can be made about spying on any other country... everyone knowing what everyone else is doing has a stabalizing affect. All bad decisions are made in fear, which brought on by ignorance, and governments, whose decisions affect millions, need all the tools possible to make correctly informed decisions.
  • China?? (Score:5, Insightful)

    by nephridium (928664) on Saturday June 17, 2006 @01:47PM (#15555327)
    rarer are spy planes having to land on enemy territory, but it happened in 2001 to a US spy plane over an un-declared enemy (China, and that's a topic in itself)
    What's with all this hate mongering against China? Why was this totally OT snippet even up there anyway? To keep us reminded that there are "bad guys" out there and when we think about harddisks we also should be completely aware that we should be afraid, very afraid of an "undeclared" enemy?

    China may have different attitudes and morals standards than the US, but they are doing many things right as well; more than western media tends to portray (e.g. according to the CIA world factbook [odci.gov] China has a lower percentage of citizens suffering from poverty than the richest country in the world (namely the US)). I don't want to whitewash anything, but reading things like "undeclared enemy" in a tech article on an international website just pisses me off.
    • Re:China?? (Score:3, Insightful)

      >>rarer are spy planes having to land on enemy territory, but it happened in 2001 to a US spy plane over an un-declared enemy (China, and that's a topic in itself)
      >What's with all this hate mongering against China?
      When your spy plane is making an emergency landing because another country's fighter just rammed it, it does take a while to start thinking of that country as a friend again.
  • by linuxrocks123 (905424) on Saturday June 17, 2006 @02:10PM (#15555415) Homepage Journal
    > ...undeclared enemy (which is China, and that's a topic in itself).

    China is not an enemy. We buy a ton of stuff from them. They buy a ton of stuff from us. Our businesses have offices there. Our colleges have exchange programs with them.

    Yeah, our diplomatic relations are a little bit strained over things like Taiwan, but we're nowhere near going to war with them. If you're a troll, shame on you. In any case, shame on the Slashdot editors for choosing this ignorant or trolling person's story.
  • Not a spy plane! (Score:5, Informative)

    by Bowling Moses (591924) on Saturday June 17, 2006 @03:00PM (#15555588) Journal
    The US aircraft alluded to was a US Navy EP-3E Aries II [wikipedia.org], a slow four-engined turboprop plane based on a passenger airliner. It's a surveillance aircraft, not a spy plane. It's out in the open, in international airspace (usually), and a modern military will immediately pick up on where it is and what it's doing. It's completely dependent on international treaties to not get shot down by whoever it's checking out. A SR-71 or U-2 on a secrete high-altitude flight over a hostile nation it isn't.
  • Waste of money (Score:3, Interesting)

    by kimvette (919543) on Saturday June 17, 2006 @03:30PM (#15555678) Homepage Journal
    125 lbs' worth of equipment to securely scramble a hard drive? Let me guess, the contractor is going to spend time "miniaturizing" it and charge several hundred grand per unit, right?

    I have a solution, with the total weight being under 5 lbs and total cost being under $130 (not counting any logic/switching required to enable it).

    Keep in mind:

      - the aircraft is disabled
      - flight instrument interference is a non-issue
      - The HDD not only does not have to be usable, it is intended to be unusable after this process
      - 12V, 24V, and 48V taps should all be readily available in the aircraft (NiMH batteries would suffice)

    Ready?

    Here are the required components:

      - a heavy-duty consumer-level inverter costing under $100 in bulk
      - a Radio Trash (or generic) degausser costing well under $30 in bulk.

    Total weight: under 5 lbs. Renders a hard drive unusable in a couple of seconds.
  • by squoozer (730327) on Saturday June 17, 2006 @04:34PM (#15555864)

    If I needed to destroy a the data on a drive in seconds I would simply heat it well above the curie temperature [wikipedia.org] for the magnetic material being used. If you are feeling really paranoid add a variable field strength magnet as well - once above the curie temperature you wouldn't need much of a magnet to make sure things were well scrambled.

If I have seen farther than others, it is because I was standing on the shoulders of giants. -- Isaac Newton

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