NIST Special Publication 800-38F, Recommendation for Block Cipher Modes of Operation: Methods for Key-Wrapping
December 21, 2012

NIST announces the release of Special Publication 800-38F, Recommendation for Block Cipher Modes of Operation: Methods for Key Wrapping. This publication describes cryptographic methods for the protection of the confidentiality and integrity of cryptographic keys. In addition to clarifying that some previously-approved methods are permitted for key wrapping, this publication specifies two deterministic authenticated-encryption modes of operation of the Advanced Encryption Standard (AES) algorithm: the AES Key Wrap (KW) mode and the AES Key Wrap With Padding (KWP) mode. An analogue of KW, called TKW, with the Triple Data Encryption Algorithm (TDEA) as the underlying block cipher, is also specified to support legacy applications. 
 
A specification of the AES Key Wrap had been available since 2001 on the Computer Security Resource Center web site; SP 800-38F officially approves this method. The AES Key Wrap With Padding mode is a variant that provides a specific padding scheme in order to promote interoperability; this variant was originally specified in 2009 under the auspices of the Internet Engineering Task Force, in Request for Comment 5649.