Techniques for Key Wrapping | Pre-Draft Call for Comments on NIST SP 800-38F

NIST plans to revise Special Publication (SP) 800-38F, Recommendation for Block Cipher Modes of Operation: Methods for Key Wrapping (2012). This announcement is a pre-draft call for comments to solicit preliminary feedback on SP 800-38F.

The following are the two main goals for the revision:

1. The specification of TKW should be removed because its underlying block cipher, TDEA, is no longer approved.
2. The approval in Section 3.1 of unspecified combinations of an approved encryption mode with an approved authentication method should be revisited because such combinations may introduce unexpected security vulnerabilities compared to fully specified methods for authenticated encryption.  (See the NIST page on authentication for block cipher modes for more information, including links to some of the relevant security analysis.)

NIST requests feedback on all aspects of this publication, especially the following questions:

• What ad hoc combinations—approved encryption mode and approved authentication method—are currently implemented, in practice?
• Should NIST limit the approval to an explicit set of such combinations that occur within prominent protocols?

The public comment period is open through July 10, 2026. Send comments to ciphermodes [at] nist.gov (ciphermodes[at]nist[dot]gov) with “Pre-Draft Comments on SP 800-38F” in the subject line. Comments received in response to this request will be posted on the publication page after the due date. Submitters’ names and affiliations (when provided) will be included, while contact information will be removed.