How do I get rid of a hard disk without exposing my source code?

Question

What is the proper way to dispose an old hard disk which contains my source code and other intellectual property? I was about to throw it away in the recycle box but thought better to check it with SO users first.

Answer 1

if the data is very sensitive you should have the drive destroyed.

Answer 2

Hammer.Smash(oldDrive);

Obviously, not such a good idea if you jsut want to give away a perfectly good working drive and need to guarantee data is erased.

In that case I would use a commercial low level drive deletion application. Never used one myself so I don't have any links. ANyone else?

Answer 3

Reformatted harddrives are easily recovered. You need at the least some kind of "secure format" program that overwrites the whole thing with random data a few times.

In linux, you can do this (where hdb is the disk):

dd if=/dev/random of=/dev/hdb

If you're paranoid enough, you can also drill a hole through it, or otherwise physically mangle the platters.

Answer 4

You can run a data eraser tool over it first, such as Eraser, which is a free tool, use the Guttmann option, which overwrites data 35 times with 'pseudorandom' noise ( edit: as a comparison, the US Department of Defense only requires 7 overwrites)

It will take a while, but it will largely guarantee a dumpster diver wont get your old data

EDIT There is a discussion here on what format (DOD vs Guttman vs NSA) to really wipe a drive, in summary postulates that unless you have something 'really illegal' then you should feel safe using Guttman.

Answer 5

Depending how paranoid you are, a format might not be enough. I usually make it one big Linux partition on it, and then cat /dev/zero > /dev/hda, then format it and install Linux on it. The truly paranoid will rely on one of the secure erase programs that will overwrite the whole thing with first one bit pattern then another and then another. There is a FIPS standard for that.

Of course, the military goes one better and will slag the disk with thermite, then bury the slag in a secure facility.

Answer 6

A few holes drilled thru it should take care of it.

Answer 7

There are some free utilities out there which will overwrite your hard disk (or specific files) with random data many times over, making data recovery very, very expensive. GNU Coreutils has a program called shred, Microsoft/SysInternals has one called SDelete, and there are other free alternatives.

Answer 8

take off the cover with a torx wrench, and pry the platters up with a screw driver.

Answer 9

Darik's Boot and Nuke ("DBAN") has been recommended to me in the past, though I've never used it. (http://sourceforge.net/projects/dban/)

Answer 10

This seems like lots of fun to answer :)

You can use the magnets for all kinds of fun, they are super strong.

I would personally go for some thermite, it's lots of fun: http://en.wikipedia.org/wiki/Thermite

Burns at 4000 degrees

Answer 11

Oliver Jones nailed it. DBAN that sucker if you need to reuse the drive with the sensitive information safely destroyed.

If you don't need the drive anymore, well, then actually destroy it. Large hammers, fire, and shredding devices generally work well.

Answer 12

My preferred way is to take it apart and use the voice coil magnets to stick the platters to the fridge for a few days. It has the advantage of resulting in a pile of HDD platters (they look cool and make good mirrors) and a few REALLY STRONG magnets.

As pointed out elsewhere, this will only stop most people. FBI, CIA, KGB, China and friends won't even blink.

Answer 13

I prefer a program called KillDisk by LINK

Answer 14

If you want to ensure the data on the harddrive is unrecoverble, I'd look into the method employed by The Great Zero Challenge:

We used the 32 year-old Unix dd command using /dev/zero as input to overwrite the drive. Three data recover companies were contacted. All three are listed on this page. Two companies declined to review the drive immediately upon hearing the phrase 'dd', the third declined to review the drive after we spoke to second level phone support and they asked if the dd command had actually completed (good question).

(Recently reported on Slashdot).

Answer 15

Do the dd command as described above, but do it several times. I hear there's a kind of power law where each write makes it less likely to retrieve anything and a handful of writes push the probability of old data surviving into the realm of "impossibility"

If you do this on windows os, I'd just use a live cd like Knoppix.

Answer 16

The simplest way i find is to unscrew the covers and fill them with sand or something similar.

While you're in there you can pull out the magnets which are very useful

Answer 17

The US Government purges the drives with something similar to bzcrypt to randomize the empty space with 7 passes, then the drives are shredded...literally, just like a paper shredder, but designed for shredding hardware.

No joke

Scot

Answer 18

True data destruction for hard drives comes only from destroying the drive and grinding it to bits.

Efective destruction comes from writing "random" data over the contents of the drive several times. The US Government has a seven pass method they use. At least a couple of those passes are random, others are all ones, all zeroes or some pattern.

If you're just talking about personal sensitive data in the realm of PII or family secrets, deleting the contents then using dd from /dev/zero and/or /dev/random will work if you're in a unix environment and you don't trust the secure erase tools provided with your OS.

If you're talking about corporate/government secrets, it may be worth looking into a disposal/destruction service. Then again, if you're talking about government secrets you probably wouldn't be asking here.

The reason complete destruction is the only absolute method has to do with the physics of magnetic media. When you overwrite a value onto disk the magnetic strength of the bit is not the same as it would have been the first time around. Think of it like bending a paperclip. Bend it once (write a one), then unbend it (overwrite with zero), and you can tell it's been bent before. This information can be used to recover the data through an overwrite or two. Melt the paperclip (physically destroy the drive) and it becomes hard to know there was a paperclip in the first place.

In most cases a "secure delete" - assuming it's a trustworthy one - and full format is sufficient.

Answer 19

Too late for you, but if you are working with data that is this sensitive to you, consider encrypting your drives with something like BitLocker.