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Geek Culture / Personal Data Safe?

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Uncle Sam
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Posted: 30th Sep 2009 02:20 Edited at: 30th Sep 2009 02:22
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So, I sold a hard drive a few a days ago. I was trying to figure out how to wipe it because it was a laptop hard drive. So, I used a Linux Puppy CD and booted on that, then formatted it from the "start menu" under one of those options....don't remember what it was.

Question: I realized after I shipped it that I don't know how much this actually does. Do you think my personal info (passwords, credits cards, programming files) are safe? I heard that sometimes formatting does not completely remove everything.

Thanks.

EDIT: I'm not entirely sure if I deleted the partitions. All I know is that I formatted it to the Windows format.

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BearCDP
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Posted: 30th Sep 2009 02:50
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Typically, formatting a drive does not get rid of the physical data on it unless you specify when performing the format to do a zero-fill. There are still magnetized bits on there, all the formatting does is take away a drive's roadmap that corresponds with how the files are organized and denotes which parts of memory are currently occupied by data. If your browser or other software stored passwords, credit cards, code, etc. then it is probably still on there in one form or another. Assuming your buyer isn't actively looking for sensitive data using a data recovery tool, then over time those bits with your data will get rewritten with new data.

The proper term for a zero-fill is a "low-level format". Last time I went looking for this, you could get a low-level formatter from the manufacturer of your particular hard drive.
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Jeff032
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Posted: 30th Sep 2009 02:58
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I believe it is recommended that you zero-fill the drive ~7 times.

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Uncle Sam
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Posted: 30th Sep 2009 03:34
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I'm doomed.

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QuothTheRaven
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Posted: 30th Sep 2009 05:10
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Quote: "I believe it is recommended that you zero-fill the drive ~7 times."

Correct. 7 times is the average number to remove the data from the cluster tips. Formatting means everything is there exactly as you left it, it's just marked as usable space.

DelvarWorld
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Uncle Sam
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Posted: 30th Sep 2009 08:09 Edited at: 30th Sep 2009 08:09
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I am so doomed. May as well just ship him my credit card as well.

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Thraxas
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Posted: 30th Sep 2009 09:34
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You're assuming that the other person is going to be looking for all your data.

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David R
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Posted: 30th Sep 2009 13:48 Edited at: 30th Sep 2009 13:54
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Quote: "Correct. 7 times is the average number to remove the data from the cluster tips. Formatting means everything is there exactly as you left it, it's just marked as usable space."


Zeroing it once is entirely sufficient unless you're under attack from a government agency with access to scanning electron microscopy or an X-ray diffraction facility (and even then it's practically impossible, because where the drive head fails to complete reset regions to zero, it's normally inconsistent and sprawled across the drive, so you would just be recovering garbage. Scary! )

All the "You must zero it [n] times" is bogus scaremongering. Yeah, doing it more than once improves the chance that the magnetic regions are properly reset to 0 (rather than lingering just above 0 and being a suspect '1') but the data left even by the most 'lazy' drive head will be complete and utter crap. So it's diminishing returns

09-f9-11-02-9d-74-e3-5b-d8-41-56-c5-63-56-88-c0
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Grog Grueslayer
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Posted: 2nd Oct 2009 19:57
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A decent magnet close to the drive would scramble the data so much that it would be impossible to reconstruct it. But don't worry... 95% of the people out there wouldn't even think about restoring the drive.

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NeX the Fairly Fast Ferret
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Posted: 2nd Oct 2009 20:04
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Quote: "A decent magnet close to the drive would scramble the data so much that it would be impossible to reconstruct it."


Wasn't this theory debunked years ago? I think you'll find most electric motors such as that used to spin the drive up would wipe them every time they turned on if this was the case.

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Grog Grueslayer
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Posted: 2nd Oct 2009 22:43
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True the size and strength of the magnet is a factor but when I said decent I didn't mean a typical refrigerator magnet.

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Jeku
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Posted: 2nd Oct 2009 23:48
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It's true. If you're a CIA agent about to crash into a foreign jungle with sensitive hard drives, the quickest way to destroy the data is with a giant magnet. Simply hammering or opening the hard drive does not guarantee the data can not be recovered.


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NeX the Fairly Fast Ferret
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Posted: 2nd Oct 2009 23:59 Edited at: 3rd Oct 2009 00:01
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http://www.cobolhacker.com/?p=488

You need to sweep a magnet touching the surface of the platter. I once read that a magnet powerful enough to wipe a HDD externally would suck the iron from your blood. I wonder; could a magnetic pole shift wipe a HDD?

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Grog Grueslayer
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Posted: 3rd Oct 2009 00:32
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Quote: "I once read that a magnet powerful enough to wipe a HDD externally would suck the iron from your blood. I wonder; could a magnetic pole shift wipe a HDD?"


Yeah I'd say a polar shift would wipe HDs as well as a nuclear blast... the radiation kills us and the electromagnetic pulse generated by the nuke will kill any electronics and wipe HDs.

We can get degaussers that can wipe a drive quickly:
http://www.veritysystems.com/degaussers/degausser.asp?id=1240

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NeX the Fairly Fast Ferret
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Posted: 3rd Oct 2009 00:35
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What about SSDs?

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TheComet
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Posted: 3rd Oct 2009 00:45 Edited at: 3rd Oct 2009 00:50
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Quote: "I once read that a magnet powerful enough to wipe a HDD externally would suck the iron from your blood."


Your statement in honour, but I must disagree with that, because the iron in your blood is not ferromagnetic, it is in a charged ionic form, so it will not be attracted by magnets.

The electromagnet at the head must be quite strong to change polarity of one of those bits if what you say is true... Wait a sec... *google* *google*

TheComet


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NeX the Fairly Fast Ferret
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Posted: 3rd Oct 2009 00:48
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Well, I'd imagine it'd be an exponential falloff, wouldn't it? So every time the distance doubles the effect halves. Or something. I dunno. I dropped science at GCSE.

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TheComet
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Posted: 3rd Oct 2009 00:52
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You can of course send your HDD out into space near one of these...

TheComet


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BMacZero
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Posted: 3rd Oct 2009 02:28
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Just change your passwords and watch your credit card bill for a while. Done .



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Grog Grueslayer
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Posted: 3rd Oct 2009 10:01
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Quote: "What about SSDs?"


I'm not sure if they would survive a nuke either. The electronics would probably fry but the data itself may be safe. Lets hope we never have to find out.

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Thraxas
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Posted: 3rd Oct 2009 10:23
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Quote: "Lets hope we never have to find out."


Well I've started collecting bottlecaps in case it should ever happen... I'll be rich...

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BMacZero
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Posted: 3rd Oct 2009 16:31 Edited at: 3rd Oct 2009 16:32
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[b][/b]



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