New Impossible Differential Attacks on Camellia

Dongxia Bai; Leibo Li

Paper 2011/661

New Impossible Differential Attacks on Camellia

Dongxia Bai and Leibo Li

Abstract

Camellia is one of the most worldwide used block ciphers, which has been selected as a standard by ISO/IEC. In this paper, we propose several new 7-round impossible differentials of Camellia with 2 $FL/FL^{-1}$ layers, which turn out to be the first 7-round impossible differentials with 2 $FL/FL^{-1}$ layers. Combined with some basic techniques including the early abort approach and the key schedule consideration, we achieve the impossible differential attacks on 11-round Camellia-128, 11-round Camellia-192, 12-round Camellia-192, and 14-round Camellia-256, and the time complexity are $2^{123.6}$, $2^{121.7}$, $2^{171.4}$ and $2^{238.2}$ respectively. As far as we know, these are the best results against the reduced-round variants of Camellia. Especially, we give the first attack on 11-round Camellia-128 reduced version with $FL/FL^{-1}$ layers.

Metadata

Available format(s): PDF PS
Category: Secret-key cryptography
Publication info: Published elsewhere. Unknown where it was published
Keywords: Camellia Impossible Differential Cryptanalysis Impossible Differential Attack.
Contact author(s): baidx10 @ mails tsinghua edu cn
History: 2011-12-09: received
Short URL: https://ia.cr/2011/661
License: CC BY

BibTeX

@misc{cryptoeprint:2011/661,
      author = {Dongxia Bai and Leibo Li},
      title = {New Impossible Differential Attacks on Camellia},
      howpublished = {Cryptology {ePrint} Archive, Paper 2011/661},
      year = {2011},
      url = {https://eprint.iacr.org/2011/661}
}