| When data is written to digital media, such as hard drives, mobile computers, external/removable hard drives, personal digital assistants, flash/thumb drives, etc., there is risk of data loss and/or compromise.
An organizational assessment of risk guides the selection of media and associated information contained on that media requiring restricted access. Organizations need to document in policy and procedures, the media requiring restricted access, individuals authorized to access the media, and the specific measures taken to restrict access.
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 if accessed by other than authorized personnel. In these situations, it is assumed the physical access controls where the media resides provide adequate protection.
As part of a defense-in-depth strategy, the organization considers routinely encrypting information at rest on selected secondary storage devices. The employment of cryptography is at the discretion of the information owner/steward. The selection of the cryptographic mechanisms used is based upon maintaining the confidentiality and integrity of the information.
The strength of mechanisms is commensurate with the classification and sensitivity of the information.
Information at rest, when not encrypted, is open to compromise from attackers who have gained unauthorized access to the data files. |
