If you’re erasing data from a hard disk drive – whether for throwing it away or resale - you’re going to want the data gone forever, especially if it contains sensitive information. Here’s how you can achieve that.
When you delete a file, it isn’t ‘deleted’ in the way you think it is. All data on a hard disk drive is stored as a series of 1s and 0s. When you hit the delete button on a file, all your operating system is doing is marking the space they’re taking up as free until something else needs to be stored there. In the past, we’ve demonstrated that, with the use of free data recovery software, you can recover data that’s been deleted pretty easily. Moving the deleted files to the recycle bin won’t do the trick either, and not even formatting your hard drive will render the data unrecoverable. What you actually need to do is undertake a process known as ‘sanitisation’, which can be done using third party software. What these eraser tools do is wipe over every sector of your hard disk drive with random data, so not even the most experienced hard drive recovery specialist will be able to recover your data.
On a Windows machine, if you want to delete a file, you just press the delete key; and if you want to bypass the Recycle Bin altogether, hold the shift key as you’re doing so. But as explained above, your data could still be recovered by an amateur with access to basic, free data recovery software, let alone a hard drive recovery expert. On a traditional, mechanical HDD, you need to make sure that those 1’s and 0’s making up your data are well and truly overwritten. A simple, free and effective tool is Eraser. Eraser has been around for years, and is an advanced security tool that allows you to completely remove data from your hard drive. The free software overwrites the data on your hard drive several times with specially selected patters, and is currently supported on all versions of Windows from XP onwards. The best thing about eraser, though, is that it’s free, and the source code is released under GNU Public License.
The patterns that Eraser uses for overwriting are based on data from researchers or government agencies, with the sole purpose of rendering the data unrecoverable even to the most skilled hard drive recovery expert. Although it’s designed as an advanced-level data security tool, it has a really simple user interface and is incredibly simple to use. You can view a detailed guide on their Eraser’s website, but simply put, you just need to point it to a file or folder and it overwrites it with random data. There’s a also a scheduler tool, so you can wipe certain parts of your hard drive periodically.
Of course, if you are disposing of a hard drive, we’d always recommend physically smashing it as well as securely erasing it - a hammer to the platters will do the trick. Just to be on the safe side. Solid state drives (SSDs) store data slightly differently so require a different approach, which is something we’ll be covering in a future article.
