Information system media includes both digital media (e.g., diskettes, magnetic tapes, external/removable hard drives, flash/thumb drives, compact disks, digital video disks) and non-digital media (e.g., paper, microfilm). A controlled area is any area or space for which the organization has confidence that the physical and procedural protections provided are sufficient to meet the requirements established for protecting the information and/or information system. This control applies to portable and mobile computing and communications devices with information storage capability (e.g., notebook computers, personal digital assistants, cellular telephones). Telephone systems are also considered information systems and may have the capability to store information on internal media (e.g., on voicemail systems). Since telephone systems do not have, in most cases, the identification, authentication, and access control mechanisms typically employed in other information systems, organizational personnel exercise extreme caution in the types of information stored on telephone voicemail systems. An organizational assessment of risk guides the selection of media and associated information contained on that media requiring physical protection. Organizations document in policy and procedures, the media requiring physical protection and the specific measures taken to afford such protection. The rigor with which this control is applied is commensurate with the FIPS 199 security categorization of the information contained on the media. For example, fewer protection measures are needed for media containing information determined by the organization to be in the public domain, to be publicly releasable, or to have limited or no adverse impact on the organization or individuals if accessed by other than authorized personnel. In these situations, it is assumed that the physical access controls to the facility where the media resides provide adequate protection. The organization protects information system media identified by the organization until the media are destroyed or sanitized using approved equipment, techniques, and procedures. As part of a defense-in-depth protection strategy, the organization considers routinely encrypting information at rest on selected secondary storage devices. FIPS 199 security categorization guides the selection of appropriate candidates for secondary storage encryption. The organization implements effective cryptographic key management in support of secondary storage encryption and provides protections to maintain the availability of the information in the event of the loss of cryptographic keys by users. NIST Special Publications 800-56 and 800-57 provide guidance on cryptographic key establishment and cryptographic key management. Related security controls: CP-9, RA-2.