Recommendation for Block Cipher Modes of Operation: Three Variants of Ciphertext Stealing for CBC Mode

Dworkin, Morris

doi:https://doi.org/10.6028/NIST.SP.800-38A-Add

SP 800-38A Addendum

Recommendation for Block Cipher Modes of Operation: Three Variants of Ciphertext Stealing for CBC Mode

Date Published: October 2010

Planning Note (3/24/2022): NIST has announced its decision proposal to REVISE SP 800-38A (and move this Addendum into the revised SP 800-38A). Public comments may be submitted by April 25, 2022. See the announcement for full details.

Author(s)

Morris Dworkin (NIST)

Abstract

A limitation to Cipher Block Chaining (CBC) mode, as specified in NIST Special Publication 800-38A, is that the plaintext input must consist of a sequence of blocks. Ciphertext stealing is a padding method in which the required padding bits are "stolen" from the penultimate ciphertext block. This addendum to SP 800-38A specifies three variants of CBC mode with ciphertext stealing. These variants, which differ only in the ordering of the ciphertext bits, can encrypt any input whose bit length is greater than or equal to the block size. Unlike conventional padding methods, these variants do not expand the length of the data.

Keywords

block cipher; ciphertext stealing; cryptography; encryption; mode of operation

Control Families

System and Communications Protection

Documentation

Publication:
SP 800-38A Addendum (DOI)
Local Download

Supplemental Material:
None available

Other Parts of this Publication:
SP 800-38A

Document History:
10/21/10: SP 800-38A Addendum (Final)

Topics

Security and Privacy
authentication; cryptography