A computer will store your files on a “hard drive”; specifically a stack of spinning disks coated in a magnetic film. This film acts like billions of tiny magnets, each of which can be in one of two positions, representing either a one or a zero. All of your files are encoded on these disks as sequences of ones and zeros. To keep things organised, the hard drive has a table of contents that indicates which parts of the drive are currently in use and where each file is stored.

Deleting a file only deletes the file’s information from the drive’s table of contents; the ones and zeros that make up the file remain on the drive. Until this data is overwritten, it is easy enough to look at this ghost data and reconstruct the file. An analysis of second hand hard drives from eBay found 40% contained personal information that could be recovered in this way. So, its not enough just to remove the drive and dispose of it, the technique we use literally renders the drive completely unreadable, EVER!!

Scroll down to see a video of the device in action.