Cryptology ePrint Archive: Report 2016/1170

Impossible-Differential and Boomerang Cryptanalysis of Round-Reduced Kiasu-BC

Christoph Dobraunig and Eik List

Abstract: Kiasu-BC is a tweakable block cipher proposed by Jean et al. at ASIACRYPT 2014 alongside their TWEAKEY framework. The cipher is almost identical to the AES-128 except for the tweak, which renders it an attractive primitive for various modes of operation and applications requiring tweakable block ciphers. Therefore, studying how the additional tweak input affects security compared to that of the AES is highly valuable to gain trust in future instantiations. This work proposes impossible-differential and boomerang attacks on eight rounds of Kiasu-BC in the single-key model, using the core idea that the tweak input allows to construct local collisions. While our results do not threat the security of the full-round version, they help concretize the security of Kiasu-BC in the single-key model.

Category / Keywords: secret-key cryptography / cryptanalysis, tweakable block cipher

Original Publication (with major differences): CT-RSA 2017

Date: received 20 Dec 2016

Contact author: eik list at uni-weimar de

Available format(s): PDF | BibTeX Citation

Version: 20161228:141104 (All versions of this report)

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