What is the data storage surface of a hard disk made of? I’m thinking chemicals might be the best solution for the do-it-yourselfer. There are several highly corrosive substances that are perfectly legal to own. Hydrochloric acid is used to clean stains off of driveways, patios, and other cement surfaces. You can get that, usually under the name “muriatic acid,” at any hardware store. Drain cleaners use either lye or (if it’s the “safe for plastic pipes” kind) sulfuric acid. I think oven cleaner uses lye, too. It probably wouldn’t be too difficult to rig up something that would inject corrosive chemicals into the hard drive if you ran a certain program. The beauty of this solution is that it’s more subtle than the more, er, dramatic methods. If you combine the acid injection with a shutdown (“Sure thing, officer, just let me power down the computer and you can take it to the station”) you’d probably have more than enough time to render the date surface unreadable.
Yeah, I believe the “GHOST” people used to provide a utility called “GDISK”, which was their partitioning utility.
They have a partition flag called /DOD. When you partitioned using that type, the software zeroed the drives in question. All zeros for the whole drive.
Then it ran again. And again.
I don’t remember how many runs it went through, but memory indicates either 3 or 5.
I used it one time when disposing of computers at MBNA’s [Credit Card guys] headquarters.
That’s not really the same. With Trucrypt, there’s an optional second password, with the real data stored in what appears to be free space at the end of the container following dummy data. You still have access to the real data. With sufficient persuasion, you might give up the real password. And you’re not going to fool me with that “there was only one password” line.
With the extra required file, once it’s overwritten enough times, the data is not recoverable.
Not quite sure what you’re getting at here.
From http://www.truecrypt.org/docs/hidden-volume.php :
The principle is that a TrueCrypt volume is created within another TrueCrypt volume (within the free space on the volume). Even when the outer volume is mounted, it is impossible to prove whether there is a hidden volume within it or not, because free space on any TrueCrypt volume is always filled with random data when the volume is created and no part of the (dismounted) hidden volume can be distinguished from random data. Note that TrueCrypt does not modify the file system (information about free space, etc.) within the outer volume in any way.
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When you create a TrueCrypt volume, you are given the option of also creating a hidden volume within the outer volume. While the person trying to get your data can’t prove, given the password to the outer volume, that there actually is an inner volume, they may operate on the assumption that there is. The data in the inner volume is still accessable by you, and therefore to anyone who can (by whatever means) get you to give them the password for the inner volume. Perhaps they can convince you to give up the password by threats or bribes. Or perhaps they already obtained that password by surveilance or by some other means. The point is, if it’s still accessible to you, it’s still accessible.
On the other hand, if a file of pseudo-random data is also required to decrypt the data, and if the contents of that file aren’t known to anyone, and if that file is overwritten to the point that its contents are not recoverable, then the encrypted data isn’t recoverable by anybody.
I see. So you’re saying use, in addition to the hidden volume within the outer volume, a keyfile that’s needed to decrypt the data. Then all you have to do is kill that file when the cops come busting in, which should be possible since it would be a rather small file and could be wiped quickly by any of the aforementioned programs. Looking back I guess this is what you were saying, I just couldn’t quite grok it.
It sounds like this would actually be a system to accurately fit the OP’s question. The keyfile could be on your PC’s HD and a floppy (or USB dongle, etc.) could have an autorun program that would nuke that particular file quickly. Permanently destroying the keyfile for a robustly encrypted set of data is essentially equivalent to destroying that data.
I wonder if any super secret government agencies use a system like this. For other applications I suppose it’d even be possible to set it up as a virtual dead man’s switch, i.e. a specific password needs to be entered every X number of minutes or else a scheduled program nukes the keyfile. Again, no need to nuke all the data in hurry if it’s all sufficiently encrypted.
Forget thermite. This shit is powerful!
You may already have it.
If you’re using Windows XP, at the command prompt, “CIPHER /W:C:”, will wipe the free space of drive C:. You can replace “C:” with your favorite drive letter to wipe it instead.
This may be one of those features only present in XP Pro–I don’t have an XP Home system around to try it on.
Fast it isn’t, so it’s useless for the OP’s purpose (and assumes that the desired files have already been deleted, anyway).
Now that is a job I could love.