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8.2.3.2 Key Update Function

NIST platform security: roots of trust, firmware and secure enclaves SP 800-57 Part 1 Rev. 4
All changes in this version
first version loaded 8 Key-Management Phases and Functions part of 8.2.3

Title

Key Update Function

Control

If the “value” of the new key is dependent on the value of the old key, the process is known as key update (i.e., the current key is modified to create a new key). Key update is a special case of key derivation (see Section 8.2.4 ), where the derived key replaces the key used to derive it. For example, suppose that K 1 is used as an encryption key. When K 1 needs to be replaced, it is used to derive K 2. K 2 is then used as the new encryption key until it is replaced by K 3, which is derived from K 2. Key update could result in a security exposure if an adversary obtains a key in the chain of keys and knows the update process used; keys subsequent to the compromised key could easily be determined. Federal applications shall not use key update (also, see [ SP800-152 ]).