A few weeks ago, we talked about what to do when your hard drive dies and you want to save your data. Well, now we’re going to talk about the opposite approach. When you have a working hard drive and you want the data on it gone.
This is something that not a lot of people think about, but you should be keeping it in mind every time you get rid of or replace a computer. There’s all sorts of personal information that gets saved onto a computer’s hard drive and there are a lot of disreputable people out there who will attempt to take advantage of this. You never know what that guy on Craigslist that you sold your old iMac to will do it. And, even if you turn your computer over to a recycler, there is a good chance that it will end up in a landfill where people troll for computers that they can steal sensitive data from.
Luckily for us, there are two easy ways to destroy your data so that nobody else can steal it. The first (and the most fun!) way to get rid of sensitive information is to physically destroy your hard drive. The other way is to overwrite your hard drive multiple times. Think of your hard drive like an embarrassing polaroid photo of yourself. If you don’t want anybody to see a picture of you in that awful Halloween costume you wore in third grade, you can rip the photo into a million little pieces (physical destruction) or you can cover it with so much paint that nobody will ever be able to find a photo underneath (overwriting).
Let’s start with physical destruction. First of all, this might not be the best of options if you’re going to be selling your computer or even giving it away to someone. Most people don’t get a lot of use out of a computer with no working hard drives in it. If you do go this route and then you pass your computer along to someone else, you might want to put a brand new hard drive in for them. It’s the nice thing to do.
There are a few different ways to physically destroy a drive. If you want it done professionally, there are companies that can shred a hard drive for you in an industrial shredder. This will cost you a few pretty pennies, but it’s an efficient way to make sure that your drive is completely annihilated. If you want to destroy your hard drive for free, all you need is a hammer, a screwdriver and a lot of pent up rage. I recommend picking a fight with the person in your life who most pushes your buttons. It will get you into the best frame of mind. The most efficient way is to get a drill, a pair of goggles and then to start drilling holes into your drive. The most satisfying way to destroy your drive is to disassemble it completely and smash the pieces. Your data is stored on round platters inside it. Those are the only components that you actually need to destroy. Everything else is just for fun.
If you’re not feeling physically destructive or you don’t want to tell your grandmother, “I destroyed the hard drive of the computer that I’m giving you because I think you’re going to steal my data,” you can overwrite your data with a random series of zeros and ones using software. If you go this route, make sure you overwrite it several times. To go back to our Polaroid analogy, most people with some know-how can get a thin layer of paint off of a picture. Anyone with the correct tools can get data off of a drive that only had a half-hearted effort at erasing it. Use a program that overwrites your drive multiple times. It’s the only way to be sure.
If you have a Mac, OS X has this built into it. Just boot your computer from the CD/DVD that came with it (you have to boot from a disk because you can’t write zeros on a hard drive that’s being used). Then go into the Disk Utility software. Click on your hard drive in the left hand column and choose the erase tab. Make sure you click on the security options button and choose the 35 pass option. It will take some time, but let the software do its thing. When the erase process is done, you should have a drive that has been scrubbed clean. For good measure, install a fresh copy of OS X on your computer. It’s nice to turn over a computer that has a working operating system on it. Plus, it’s one last level of protection. Everybody wins!
If you’re using a PC, you’ll have to install some software (or ask a geeky friend for help). A commenter last week recommended CCleaner. I’ve used it in the past and it works quite well. Just make sure you do the maximum number of passes with it and you should be all set.
Another option is simply to keep your hard drives in a safe place. That way, nobody has access to them but you. But that would be hoarding and I try not to encourage that.
Next week… Viruses! And, as always, if you have some geeky questions of your own, leave me a comment. Happy Monday!
Thanks! That is another thing that I have to deal with since I have a computer to get rid of. Since I lack expertise I was going to go with the smashing technique, but since the hard drive itself doesn’t seem to have any problems maybe I will just overwrite like a thousand times and give it away. (PS: Want an old computer that died for unknown reasons – perhaps power source? I don’t know if you are the computer-parts-hoarding type.)
I was the hoarding type, but I’ve gotten much better about not accepting computers/parts that I don’t actually need. Now, to get rid of the all of the computers/parts that I already accepted!
I’m a fan of the physical destruction. Very satisfying.
A while ago I took a couple courses in data forensics, and the topic of cleaning hard drives came up. Apparently the old “overwrite data multiple times” technique is actually unneeded – with the (very old!) MFM style hard drives, data could still be recovered after multiple writes, but with modern hard drives due to the density of data even a single overwrite is enough to prevent the recovery of data. The DOD specification that everybody holds up as the holy grail is an extreme example – they don’t necessarily think that it’s recoverable, it’s just worst-case scenario paranoia. For modern criminal investigations, data that has been overwritten once is unrecoverable.
Not picking nits, just found it fascinating since I’d always gone along with the multiple overwrites myself.
So true!
That’s the word on the street. I guess I’m just paranoid. :p
Hmmmm. The physical outlet of sledgehammering an old laptop, or the neat and tidy option of overwriting the data. I think it will depend on my mood next week when I prepare to take one of the old laptops to electronics recycling day.
Thanks, Hope!