Have you given much thought to what happens to your data when you no longer want to keep a PC around because of its being replaced by a new model? Well you should. Before you get rid of your old computer you need to securely erase all data that can be used to steal your money, or your personal information.
How do you do that? There are several ways, some of which are not effective.
Merely erasing your data does not give you any protection. That is because the data is not actually erased, it is merely marked as erased by the operating system. It is trivial to un-erase the data. If you use FDISK, FORMAT utilities, or DELETE (the standard operating system command for data removal), there is always the possibility of recovering the deleted files using Undelete, or some other data recovery software. The data must actually be overwritten, or the disk destroyed, to be rendered unreadable by normal means of recovery.
It should be noted that the National Security Agency (NSA) has methods to recover data that supposedly threatens national security that go way beyond what is available to a garden variety data thief. That being said, we can focus on making your data secure from normal attack.
Data security begins with encryption. If you data is stolen it will not be so easily read if it is encrypted. A free method of accomplishing that is by using TrueCrypt, the Open-Source on-the-fly disk encryption software.
As mentioned, overwriting is another of the methods of obscuring your data. That can be accomplished by using some free utilities. The most highly recommended seems to be Darik’s Boot and Nuke (DBAN). DBAN says it is:
…a self-contained boot disk that securely wipes the hard disks of most computers. DBAN will automatically and completely delete the contents of any hard disk that it can detect, which makes it an appropriate utility for bulk or emergency data destruction.
DBAN performs a software-only wipe, which has some limitations. According to the DBAN FAQ, contents of remapped sectors and the Host Protected Area (HPA) are NOT deleted.
The University of California at San Diego’s Center for Magnetic Recording Research offers the freeware CMRR - Secure Erase which erases ATA hard drives using their "internal secure erase command". That means that it will wipe regions of the disk that other tools can’t access, such as bad sectors and the Host Protected Area (HPA). The tool requires a DOS-based boot media which is not provided.
I DO NOT recommend using acid, or four pounds of thermite, as methods of destroying hard drive data. Watch this video to see the results of that.
Leave a Reply