Data Wiping Magnetic Media
Protecting data also includes removing files from storage devices when they are no longer needed. Simply deleting files or reformatting the drive may not be enough to ensure your privacy.
For example, deleting files from a magnetic hard disk drive does not remove them completely. The operating system removes the file reference in the file allocation table but the actual data remains on the drive. This deleted data is only overwritten when the hard drive stores new data in the same location.
Software tools can be used to recover folders, files, and even entire partitions. This could be a blessing if the erasure was accidental. But it could also be disastrous if the data is recovered by a malicious user.
For this reason, storage media should be fully erased using one or more of the methods listed in the figure.
Note: Data wiping and degaussing techniques are irreversible, and the data can never be recovered.
The image describes three different ways to wipe data from a hard disk drive. Data wiping software definition, also known as secure erase. Software tools specifically designed to overwrite existing data multiple times, rendering the data unreadable. Degaussing wand defintion, consists of a wand with very powerful magnets which is held over exposed hard drive platters to disrupt or eliminate the magnetic field on a hard drive. Hard drive platters must be exposed to the wand for approximately 2 minutes. Electromagnetic degaussing device definition, useful for erasing multiple drives. Consists of a magnet with an electrical current applied to it to create a very strong magnetic field that disrupts or eliminates the magnetic field on a hard drive. Very expensive but fast (erases a drive in seconds).
Data Wiping Other Media
SSDs are comprised of flash memory instead of magnetic platters. Common techniques used for erasing data such as degaussing are not effective with flash memory. Perform a secure erase to fully ensure that data cannot be recovered from an SSD and hybrid SSD.
Other storage media and documents (e.g., optical disks, eMMC, USB sticks) must also be destroyed. Use a shredding machine or incinerator that is designed to destroy documents and each type of media. For sensitive documents that must be kept, such as those with classified information or passwords, always keep them locked in a secure location.
When thinking about what devices must be wiped or destroyed, remember that devices besides computers and mobile devices store data. Printers and multifunction devices may also contain a hard drive that caches printed or scanned documents. This caching feature can be turned off in some instances, or the device needs to be wiped on a regular basis to ensure data privacy. It is a good security practice to set up user authentication on the device, if possible, to prevent an unauthorized person from changing any settings that concern privacy.