ISSN 1000-1239 CN 11-1777/TP

• 信息安全 •

uBlock类结构最优向量置换的高效搜索

1. 1(中国科学院软件研究所可信计算与信息保障实验室 北京 100190);2(中国科学院大学 北京 100049);3(中国星网网络系统研究院有限公司 北京 100083) (xiaodan2018@iscas.ac.cn)
• 出版日期: 2022-10-01
• 基金资助:
国家自然科学基金项目(62072445)

Efficient Search for Optimal Vector Permutations of uBlock-like Structures

Li Xiaodan1,2,3, Wu Wenling1,2, Zhang Li1,2

1. 1(Trusted Computing and Information Assurance Laboratory, Institute of Software, Chinese Academy of Sciences, Beijing 100190);2(University of Chinese Academy of Sciences, Beijing 100049);3(China Satellite Network System Institute Co., Ltd., Beijing 100083)
• Online: 2022-10-01
• Supported by:
This work was supported by the National Natural Science Foundation of China (62072445).

Abstract: The overall structure is an important feature of block cipher and also the primary research object. It has a great influence on the performance of hardware and software in the selection of rounds of block cipher. In the design process of the AES-like ciphers, when using a matrix with a non-optimal branch number for the MixColumns operation, the choice of the vector permutation, i.e., an alternative for ShiftRows, can actually improve the security of the primitive. uBlock-like structure is an AES-like structure. In this paper, we investigate the characteristics and diffusivity of uBlock-like structures, the lower bound of the number of full diffusion rounds and the equivalence class division criteria, and then we propose a search strategy for optimal vector permutations of uBlock-like structures. According to the optimal number of full diffusion rounds, the optimal branch number of the super diffusion layer, and the special properties of the diffusion layer of uBlock-like structure, we prove that the left and right vector permutations cannot be the identity transformation, and a series of optimal vector permutations of uBlock-like structures are given. The search strategy greatly reduces the number of permutation pairs that need to be tested and provides technical support for the design of uBlock-like algorithms.