How To Destroy Data
Identity theft is one of the fastest growing crimes in the world. Today, more than ever before, you should be practicing good data destruction techniques.
Paper
Most people now are probably aware of the need to shred old bank statements, but what else should you shred, and when?
And did you know there are numerous types of shredders, and numerous standards of security, depending on the level of sensitivity of your files (and your level of paranoia).
Personally, I wouldn’t use any shredder that didn’t cross-cut (versus strip-cut).
Computer Files
Securely erasing a file on a computer is not quite as simple as moving it to the recycle bin and then emptying it.
Rather than removing the data from the drive itself, most operating systems merely remove the mention of the file from whatever index it uses. This has the effect of freeing up that space on the drive, ready to be overwritten with new data, while appearing to the end user as having deleted the file.
If you accidentally delete a file, you can often recover your data using tools such as Recuva. Go ahead and try it. It even works on USB keychains and flash cards used in cameras, organisers, etc.
However, if you intentionally delete a file using standard methods, it is quite possible that other unscrupulous users of your computer might be able to unerase that file. Worse still, if they’re determined, they probably have more powerful tools to do it than I’m covering here.
The good news is that armed with this knowledge, you can use any one of a number of tools which securely erase a file by repeatedly overwriting it with random data. Tools such as Eraser for Windows, or the built in function “Secure Empty Trash” on Mac OS X (it’s on the Finder menu).
Hard Drives
So we can securely erase files from a hard drive (or flash card), but what if you need to erase an entire drive.
DBan is a Linux based auto-booting CD which will permanently destroy data on a hard drive, regardless of the OS you have installed. It’s all you’ll ever need, and it’s free.
Depending on the method you choose and the size of the device, it can take anywhere from a few minutes to a number of days to complete the process. That’s the price you pay for peace of mind.
CDs and DVDs
CDs and DVDs can be surprisingly resilient. Have you ever tried to snap one in half? Doing so would ensure the data was gone, but there are easier ways which are less injury prone.
A CD punch is a good way to solve this problem, by removing the lead-in area on the CD making it impossible to read the disc contents. These devices are cheap, but can be hard to find. I managed to pick one up at my local Maplin store for £2 (GBP).
Alternatively, there’s a CD destroyer which is a bit more pricey, but worth considering if you have a lot of discs to destroy.