Disposal Disposal is the act of dis

Disposal
Disposal is the act of discarding media with no other sanitization considerations. This is
most often done by paper recycling containing non-confidential information but may also
include other media.

Clearing
Clearing information is a level of media sanitization that would protect the confidentiality of
information against a robust keyboard attack. Simple deletion of items would not suffice for
clearing. Clearing must not allow information to be retrieved by data, disk, or file recovery
utilities. It must be resistantto keystroke recovery attempts executed from standard input devices and from data scavenging tools. For example, overwriting is an acceptable method
for clearing media.
There are overwriting software or hardware products to overwrite storage space on the
media with non-sensitive data.This process may include overwriting not only the logical
storage location of a file(s) (e.g., file allocation table) but also may include all addressable
locations. The security goal of the overwriting process is to replace written data with
random data. Overwriting cannot be used for media that are damaged or not writeable.
The media type and size may also influence whether overwriting is a suitable sanitization
method. [SP 800-36].
Studies have shown that most of today’s media can be effectively cleared by one overwrite.
Specific recommendations for clearing different media types are included in Appendix A


Purging information is a media sanitization process that protectsthe confidentiality of
information against a laboratory attack. For some media, clearing media would not suffice
for purging. However, for ATA disk drives manufactured after 2001 (over 15 GB) the
terms clearing and purging have converged.
A laboratory attack would involve a threat with the resources and knowledge to use
nonstandard systems to conduct data recoveryattempts on media outside their normal
operating environment. This type of attack involves using signal processing equipment and
specially trained personnel.
Executing the firmware Secure Erase command (for ATA drives only) and degaussing are
examples of acceptable methods for purging. Degaussing of any hard drive assembly
usually destroys the drive as the firmwarethat manages the device is also destroyed.
Degaussing is exposing the magnetic media to a strong magnetic field in order to disrupt
the recorded magnetic domains. A degausser isa device that generates a magnetic field
used to sanitize magnetic media. Degaussers are rated based on the type (i.e., low energy
or high energy) of magnetic media they can purge. Degaussers operate using either a
strong permanent magnet or anelectromagnetic coil. Degaussing can be an effective
method for purging damaged media, for purging media with exceptionally large storage
capacities, or for quickly purging diskettes. Degaussing is not effective for purging
nonmagnetic media, such as optical media [compact discs (CD), digital versatile discs
(DVD), etc.). [SP 800-36, Guide to Selecting Information Security Products]
Specific recommendations for purging different media types are included in Appendix A. If
purging media is not a reasonable sanitization method for organizations, this guide
recommends that the media be destroyed.