Key Wrap

Key Wrap constructions are a class of symmetric encryption algorithms designed to encapsulate (encrypt) cryptographic key material. The Key Wrap algorithms are intended for applications such as (a) protecting keys while in untrusted storage, or (b) transmitting keys over untrusted communications networks. The constructions are typically built from standard primitives such as block ciphers and cryptographic hash functions.

Key Wrap may be considered as a form of key encapsulation algorithm, although it should not be confused with the more commonly known asymmetric (public-key) key encapsulation algorithms (e.g., PSEC-KEM). Key Wrap algorithms can be used in a similar application: to securely transport a session key by encrypting it under a long-term encryption key.