Paper 2016/326
Square Attack on 7-Round Kiasu-BC
Christoph Dobraunig, Maria Eichlseder, and Florian Mendel
Abstract
Kiasu-BC is a tweakable block cipher presented within the TWEAKEY framework at AsiaCrypt 2014. Kiasu-BC is almost identical to AES-128, the only difference to AES-128 is the tweak addition, where the 64-bit tweak is xored to the first two rows of every round-key. The security analysis of the designers focuses primarily on related-key related-tweak differential characteristics and meet-in-the-middle attacks. For other attacks, they conclude that the security level of Kiasu-BC is similar to AES-128. In this work, we provide the first third-party analysis of Kiasu-BC. We show that we can mount Square attacks on up to 7-round Kiasu-BC with a complexity of about $2^{48.5}$ encryptions, which improves upon the best published 7-round attacks for AES-128. Furthermore, we show that such attacks are applicable to the round-reduced OCB3-like mode of the CAESAR candidate Kiasu. To be specific, we show a key-recovery attack on 7-round Kiasu$\neq$ with a complexity of about $2^{82}$ encryptions.
Metadata
- Available format(s)
-
PDF
- Category
- Secret-key cryptography
- Publication info
- Published elsewhere. ACNS 2016
- Keywords
- CryptanalysisTWEAKEYKiasuSquare Attack
- Contact author(s)
- christoph dobraunig @ iaik tugraz at
- History
- 2016-06-13: last of 2 revisions
- 2016-03-25: received
- See all versions
- Short URL
- https://ia.cr/2016/326
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2016/326,
author = {Christoph Dobraunig and Maria Eichlseder and Florian Mendel},
title = {Square Attack on 7-Round Kiasu-BC},
howpublished = {Cryptology ePrint Archive, Paper 2016/326},
year = {2016},
note = {\url{https://eprint.iacr.org/2016/326}},
url = {https://eprint.iacr.org/2016/326}
}
