Part 1: General - Computer Security Resource Center - National ...

6.2.1.5 Association with Other Entities
March, 2007
The association of keying material with the appropriate entity (e.g., the key source) shall be
either specifically identified during the distribution process (e.g., using public key certificates) or
be implicitly defined by the use of the application. See Section 6.2.3 for guidance on labeling.
6.2.1.6 Association with Other Related Information
Any association with other related information (e.g., domain parameters, the
encryption/decryption key or IVs) shall be either specifically identified during the distribution
process or be implicitly defined by the use of the application. See Section 6.2.3 for guidance on
labeling.
6.2.2 Protection Mechanisms for Information in Storage
Cryptographic information that is not in transit is at rest in some device or storage media. This
may include copies of the information that is also in transit. This information shall be protected
in accordance with Section 6.1. A variety of protection mechanisms may be used.
The cryptographic information may be stored so as to be immediately available to an application
(e.g., on a local hard disk or a server); this would be typical for keying material stored within the
cryptographic module or in immediately accessible storage (e.g., on a local hard drive). The
keying material may also be stored in electronic form on a removable media (e.g., a CD-ROM),
in a remotely accessible location, or in hard copy form and placed in a safe; this would be typical
for backup or archive storage.
6.2.2.1 Availability
Cryptographic information may need to be readily available for as long as data is protected by
the information. A common method for providing this protection is to make one or more copies
of the cryptographic information and store them in separate locations. During a key’s
cryptoperiod, keying material requiring long-term availability should be stored in both normal
operational storage (see Section 8.2.1) and in backup storage (see Section 8.2.2.1).
Cryptographic information that is retained after the end of a key’s cryptoperiod should be placed
in archive storage (see Section 8.3.1). This recommendation does not preclude the use of the
same storage media for both backup and archive storage.
Specifics on the long-term availability requirement for each key type are addressed for backup
storage in Section 8.2.2.1, and for archive storage in Section 8.3.1.
The recovery of this cryptographic information for use in replacing cryptographic information
that is lost (e.g., from normal storage), or in performing cryptographic operations after the end of
a key’s cryptoperiod is discussed in Sections 8.2.2.2 (recovery) and 8.3.1 (archive), and in
Appendix B.
6.2.2.2 Integrity
Integrity protection is concerned with ensuring that the information is correct. Absolute
protection against modification is not possible. The best that can be done is to use reasonable
measures to prevent modifications, to use methods to detect (with a very high probability) any
modifications that occur, and to restore the information to its original content when
modifications have been detected.
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