### Automated Search Oriented to Key Recovery on Ciphers with Linear Key Schedule: Applications to Boomerangs in SKINNY and ForkSkinny

Lingyue Qin, Xiaoyang Dong, Xiaoyun Wang, Keting Jia, and Yunwen Liu

##### Abstract

Automatic modelling to search distinguishers with high probability covering as many rounds as possible, such as MILP, SAT/SMT, CP models, has become a very popular cryptanalysis topic today. In those models, the optimizing objective is usually the probability or the number of rounds of the distinguishers. If we want to recover the secret key for a round-reduced block cipher, there are usually two phases, i.e., finding an efficient distinguisher and performing key-recovery attack by extending several rounds before and after the distinguisher. The total attacked number of rounds is not only related to the chosen distinguisher, but also to the extended rounds before and after the distinguisher. In this paper, we try to combine the two phases in a uniform automatic model. Concretely, we apply this idea to automate the related-key rectangle attacks on SKINNY and ForkSkinny. We propose some new distinguishers with advantage to perform key-recovery attacks. Our key-recovery attacks on a few versions of round-reduced SKINNY and ForkSkinny cover 1 to 2 more rounds than the best previous attacks.

Available format(s)
Category
Secret-key cryptography
Publication info
Published elsewhere. ToSC 2021, issue 2
Keywords
Key recoverySKINNYForkSkinnyRectangle attackMILP
Contact author(s)
qinly @ tsinghua edu cn
xiaoyangdong @ tsinghua edu cn
xiaoyunwang @ tsinghua edu cn
ktjia @ tsinghua edu cn
univerlyw @ hotmail com
History
2021-05-27: last of 2 revisions
See all versions
Short URL
https://ia.cr/2021/656

CC BY

BibTeX

@misc{cryptoeprint:2021/656,
author = {Lingyue Qin and Xiaoyang Dong and Xiaoyun Wang and Keting Jia and Yunwen Liu},
title = {Automated Search Oriented to Key Recovery on Ciphers with Linear Key Schedule: Applications to  Boomerangs in SKINNY and  ForkSkinny},
howpublished = {Cryptology ePrint Archive, Paper 2021/656},
year = {2021},
note = {\url{https://eprint.iacr.org/2021/656}},
url = {https://eprint.iacr.org/2021/656}
}

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