通信学报 ›› 2023, Vol. 44 ›› Issue (4): 137-144.doi: 10.11959/j.issn.1000-436x.2023082

• 学术论文 • 上一篇    下一篇

基于分治策略的SAT差分自动化搜索算法及其应用

胡斌1, 谈潇1, 王森鹏1,2   

  1. 1 信息工程大学密码工程学院,河南 郑州 450001
    2 密码科学技术国家重点实验室,北京 100878
  • 修回日期:2023-02-03 出版日期:2023-04-25 发布日期:2023-04-01
  • 作者简介:胡斌(1971- ),男,河南信阳人,博士,信息工程大学教授、博士生导师,主要研究方向为密码学与信息安全
    谈潇(1998- ),女,湖北鄂州人,信息工程大学硕士生,主要研究方向为分组密码自动化分析
    王森鹏(1990- ),男,河南商丘人,博士,信息工程大学讲师,主要研究方向为对称密码算法的设计与分析
  • 基金资助:
    国家自然科学基金资助项目(62102448)

SAT-based differential automatic search algorithm using divide-and-conquer strategy and its applications

Bin HU1, Xiao TAN1, Senpeng WANG1,2   

  1. 1 Department of Cryptogram Engineering, Information Engineering University, Zhengzhou 450001, China
    2 State Key Laboratory of Cryptology, Beijing 100878, China
  • Revised:2023-02-03 Online:2023-04-25 Published:2023-04-01
  • Supported by:
    The National Natural Science Foundation of China(62102448)

摘要:

为了提高自动化搜索效率,结合分治策略提出了一种基于SAT模型的最优差分特征搜索算法。利用任意部分连续轮的Matsui边界条件提供的信息,将搜索空间划分为互不相交的子集。通过分析SAT差分模型间的可满足性关系,提出一种降序分支搜索链模型。进一步地,在模型优化层面,减少了需搜索划分子集数量的方法;在算法实现层面,结合并行技术实现对模型搜索空间的约减。将加速算法应用于ARX类密码算法族SPECK,获得了 20 轮、14 轮、11 轮 SPECK-48、SPECK-96、SPECK-128 的最优差分特征,较现有最好结果分别提高了 1轮、4轮、2轮。

关键词: 差分特征, 分组密码, 自动化搜索, 分治策略

Abstract:

To improve the efficiency of automatic search, an algorithm for searching the optimal differential characteristics based on SAT model was proposed by combining the divide-and-conquer strategy.The search space was divided into disjoint subsets by using the information from Matsui boundary conditions of arbitrary continuous rounds.By analyzing the relationships between satisfiability of differential models based on SAT, a descending branch search chain model was proposed.Furthermore, at the model optimization level, the number of subsets that need to be searched and partitioned was decreased.At the level of algorithm implementation, the search space was reduced by utilizing the parallel technology.Finally, the accelerated algorithm was applied to SPECK family of ARX cryptographic algorithms.The 20, 14, 11-round optimal differential characteristics of SPECK-48, SPECK-96, SPECK-128 are obtained, which increase the previous best results by 1, 4, 2 rounds respectively.

Key words: differential characteristic, block cipher, automatic search, divide-and-conquer strategy

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