A brief guide on how to destroy data on your hard drive, either physically or with software.
It's Gone, Right?
Well, let's say your computer is packed with incriminating evidence, whether it's emails detailing business transactions or credit information that-- let's just say you forgot to file on your taxes. Bottom line, you’ve got to get rid of it. You pop the hard drive in the oven for a few hours, throw it in your pool for a few days, and heave it against a brick wall a few times. That solves that problem.
Not quite. Modern data recovery companies are able to get data off even the most physically damaged hard drives, and actually getting rid of files can be difficult. There have been cases in which drives were exposed to hazardous chemicals, burnt, covered in water for extended periods of time, and even struck by lightning and still were pronounced recoverable by tech savvy data recovery services. However, there are a few simple ways to destroy data from a hard drive—you just have to have a little knowledge of what you’re dealing with.
Knowing What To Look For
Like I said, it’s not easy to get rid of a hard drive unless you know what you’re doing. And you don’t. Luckily, it’s not really complicated.
A hard drive consists of small “heads” that read and write information on “platters,” which are small discs inside the drive. These are extremely sensitive magnetic devices, and they hold all of the data you need to get rid of. Once you get to them, you can make short work of your drive, simply by physically damaging the little discs beyond recognition.
Silver Platters
To get to these platters, you must first disassemble the hard drive. Unscrew everything and dismantle the drive until you can see the platters. You may have to use a special screwdriver; your local hardware store should have you covered. Once inside the drive, you’ll see metal discs. These are the platters. These babies are what you’re looking for: destroy them. Use any necessary method; my favorite is running a belt sander over them and then throwing them at the neighbor’s dog, but anything that sufficiently scratches the disks will work. Breaking them is great too, because you can scatter the pieces and wait for Hard Drive Trees to grow. (Note: I haven’t gotten one to grow yet). Since they're highly magnetic, it's a good idea to grab a large magnet (off the back of a set of speakers, perhaps) and run that along them.
Treat the platters like a murder weapon. After you destroy them, throw them away in different trash receptacles. Make sure that they’ll never be reassembled. However, if you properly scratch, bend, demagnetize, and break the platters, it won’t matter if a forensics team gets a hold of them; the data will physically be removed from the disk. At this point, data recovery is impossible because, well, there’s no data to recover.
Using Software
Don’t want to destroy the hard drive? Still want a secure way to get rid of the data? Well, it’s not that complex. Computer coding is written in binary code, which is represented by 1’s and 0’s. The Department of Defense has developed a standard method for writing over computer code in a way that quite frankly, isn’t as fun as throwing shiny metal discs at my neighbor’s pets, but is much more cost efficient for people that want to resell or give away their computers.
The Department of Defense’s method is known as DoD7. It recommends assigning a random date to the file, then writing over the original computer code with 0’s, or 1’s, or random 1’s and 0’s, then basically doing it all over again seven times. Hence the 7 in DoD7. Most of the time, by the second time the code’s rewritten there’s no chance of recovery, so seven rewrites should be overkill; still, it’s the good kind of overkill, so don’t assume you can run less rewrites to save time and still completely destroy your files.
You’re probably saying, “Wait, do I have to type over a program by hand in binary code seven times?” Well, no, that would be far too time consuming. Modern computer code is…well, let’s say very long, and doing this by hand isn’t feasible. Luckily, there are programs out there made for this exact purpose.
Try Eraser. Eraser is free software that does a secure deletion for you; to be safe, go ahead and run it a few times. If you want to completely erase your hard drive, programs can be found to do that by typing in “free secure file deletion” at Google.
Deletion Services
These programs take a lot of time, and can be complicated. Some don’t work that well. If you’ve got some money to spend, and you are serious about secure file deletion, some data recovery companies offer a secure file deletion service on a per hour basis. Try ESS Data Recovery for this type of thing. They know how to recover data, so it’s logical for them to know how to make data unrecoverable. Data recovery companies closely guard their secrets, but it’s safe to assume that when performing secure deletes they use methods other than just downloaded software. However, these methods are nondestructive and the drive should be returned to you in its original state. Make sure the company you choose guarantees nondestructive deletion, and make sure it’s done this sort of thing before. If you don’t want the drive back, they also provide physical destruction services, although most of the time it’s far cheaper to do it yourself (unless, of course, you simply don’t have the time or you have far too many drives to consider any home method).
Don’t Be Too Sure
Never assume that your files are gone from a hard drive if you haven’t either physically maimed the platters beyond recognition (we’re talking Friday the 13th style) or used the Department of Defense secure deletion standard. These methods are the only ways to make sure, and I mean sure, that your data doesn’t fall into the wrong hands. If you’re one of those people who really tends to worry about things, use both methods. With data recovery technology increasing every day, there’s no telling what forensic engineers will be able to do. However, there are limits to data recovery, and if you follow DoD7 guidelines or physically destroy the data, the data recovery companies won’t be able to access your data, and unless they’re willing to get really close to my neighbor’s dog, I shouldn’t have a problem.