Paper 2009/357 Original: eprint.iacr.org/2009/357 ↗
Impossible Differential Cryptanalysis of FOX
Abstract
Block ciphers are the very foundation of computer and information security. FOX, also known as IDEA NXT, is a family of block ciphers published in 2004 and is famous for its provable security to cryptanalysis. In this paper, we apply impossible differential cryptanalysis on FOX cipher. We find a 4-round impossible difference, by using which adversaries can attack 5, 6 and 7-round FOX64 with $2^{71}$, $2^{135}$ and $2^{199}$ one-round encryptions respectively. Compared to the previous best attack with $2^{109.4}$, $2^{173.4}$ and $2^{237.4}$ full-round encryptions to 5, 6 and 7-round FOX64, the method in this paper is the best attack to FOX cipher. This attack can also be applied to 5-round FOX128 with $2^{135}$ one-round encryptions.
Metadata
- Available format(s)
PDF- Category
- Secret-key cryptography
- Publication info
- Preprint.
- History
- 2009-07-22: last updated
- 2009-07-21: published
- Short URL
- https://ia.cr/2009/357
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2009/357,
author = {Zhongming Wu and Xuejia Lai and Bo Zhu and Yiyuan Luo},
title = {Impossible Differential Cryptanalysis of FOX},
howpublished = {Cryptology {ePrint} Archive, Paper 2009/357},
year = {2009},
url = {https://eprint.iacr.org/2009/357}
}