New method to describe the differential distribution table for large S-boxes in MILP and its application

Based on the method of the H-representation of the convex hull, the linear inequalities of all possible differential patterns of 4-bit S-boxes in the mix integer linear programming (MILP) model can be generated easily by the SAGE software. Whereas this method cannot be apply to 8-bit S-boxes. In thi...

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Bibliographic Details
Published in:IET information security Vol. 13; no. 5; pp. 479 - 485
Main Authors: Li, Ling-Chen, Wu, Wen-Ling, Zhang, Lei, Zheng, Ya-Fei
Format: Journal Article
Language:English
Published: The Institution of Engineering and Technology 01.09.2019
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ISSN:1751-8709, 1751-8717
Online Access:Get full text
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Summary:Based on the method of the H-representation of the convex hull, the linear inequalities of all possible differential patterns of 4-bit S-boxes in the mix integer linear programming (MILP) model can be generated easily by the SAGE software. Whereas this method cannot be apply to 8-bit S-boxes. In this study, the authors propose a new method to obtain the inequalities for large S-boxes with the coefficients belonging to integer. The relationship between the coefficients of the inequalities and the corresponding excluded impossible differential patterns is obtained. As a result, the number of inequalities can be lower than 4000 for the AES S-box. Then, the new method for finding the best probability of the differential characteristics of 4–15 rounds SM4 in the single-key setting is presented. Especially, the authors found that the 15-round SM4 exists four differential characteristics with 12 active S-boxes. The exact lower bound of the number of differentially active S-boxes of the 16-round SM4 is 15. The authors also found eight differential characteristics of the 19-round SM4 with the probability $2^{ - 124}$2−124.
ISSN:1751-8709
1751-8717
DOI:10.1049/iet-ifs.2018.5284