Paper 2001/026
OCB Mode
Phillip Rogaway, Mihir Bellare, John Black, and Ted Krovetz
Abstract
This paper was prepared for NIST, which is considering new block-cipher modes of operation. It describes a parallelizable mode of operation that simultaneously provides both privacy and authenticity. "OCB mode" encrypts-and-authenticates an arbitrary message $M\in\bits^*$ using only $\lceil |M|/n\rceil + 2$ block-cipher invocations, where $n$ is the block length of the underlying block cipher. Additional overhead is small. OCB refines a scheme, IAPM, suggested by Jutla [IACR-2000/39], who was the first to devise an authenticated-encryption mode with minimal overhead compared to standard modes. Desirable new properties of OCB include: very cheap offset calculations; operating on an arbitrary message $M\in\bits^*$; producing ciphertexts of minimal length; using a single underlying cryptographic key; making a nearly optimal number of block-cipher calls; avoiding the need for a random IV; and rendering it infeasible for an adversary to find "pretag collisions". The paper provides a full proof of security for OCB.
Metadata
- Available format(s)
-
PDF
PS
- Category
- Secret-key cryptography
- Publication info
- Published elsewhere. unpublished NIST submission
- Keywords
- AESsecret-key cryptographymodes of operation
- Contact author(s)
- rogaway @ cs ucdavis edu
- History
- 2001-04-18: revised
- 2001-04-03: received
- See all versions
- Short URL
- https://ia.cr/2001/026
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2001/026,
author = {Phillip Rogaway and Mihir Bellare and John Black and Ted Krovetz},
title = {{OCB} Mode},
howpublished = {Cryptology {ePrint} Archive, Paper 2001/026},
year = {2001},
url = {https://eprint.iacr.org/2001/026}
}
