Modern file systems and storage hardware are excellent at storing data. All of them excel at grabbing and holding sensitive files, as they have been designed to do. Their ability to keep information secure for longer is constantly improving. However, in the time spanning from punch cards to SSDs, very little has improved in their ability to remove data.
The “Delete” feature in operating systems has never really been as advertised. When data is coded on a hard drive, a link is created to a filename which represents that data in the interface. Pressing “Delete” in Windows or Mac systems has the immediate benefit of destroying that link. It does NOT impact the data on the drive.
There are some applications that make bold claims about their data destruction ability. These programs are designed to overwrite media at random. The process takes a set of garbled data and layers it over the top of existing user data, a bit like taking a pen and writing over a written sentence. When this process is finished, imprints of the original files remain. The problem is that scores of freely available applications are dedicated to recovering these imprints, which render software data destruction options ineffective.
However, there is one method of data destruction that is always effective: physical destruction of the media. Once the platters of a hard drive or the silicon of an SSD are mutilated, all existing data becomes unrecoverable. It is well-known that even advanced digital forensic techniques fail to read disks that are crushed or shredded, even in part. As great as modern storage mechanisms are, internal parts just have not been designed to perform after mechanical damage.
Putting a piece of paper into a crosscut shredder offers a sense of finality and visible evidence that documents are destroyed quickly and effectively. Destruction of electronically stored data can be equally simple and complete — with the right equipment.