Cryptology ePrint Archive: Report 2018/142

MILP-Aided Related-Tweak/Key Impossible Differential Attack and Its applications to QARMA, Joltik-BC

Rui Zong and Xiaoyang Dong

Abstract: In this paper, we study the relation of single-key impossible differentials with the related-tweakey/key ones and propose an interesting algorithm that can efficiently derive longer related-tweakey/key impossible differentials from single-key ones. With application of the MILP technique, the algorithm can be converted an automatic tool for searching related-tweakey/key impossible differentials.

We use this automatic tool to analyze QARMA-64 and give a 11-round key recovery attack, which attacks one more round than the best previous result. Moreover, we also analyze Joltik-BC-128, a internal tweakable block cipher of an authenticated encryption candidate of the CAESAR competition Joltik and our result can attack two more rounds than the result given by the cipher designers.

Category / Keywords: secret-key cryptography / Tweakable block cipher, Impossible differential attack, Related-Tweakey, MILP, Tweakey framework

Date: received 6 Feb 2018, last revised 23 Sep 2019

Contact author: zongrui3 at 163 com

Available format(s): PDF | BibTeX Citation

Version: 20190924:011543 (All versions of this report)

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