改进的SMBA算法不可能差分分析  

An Improved Impossible Differential Analysis of SMBA Algorithm

作　　者：李艳俊 李寅霜[3] 汪振 刘健 LI Yan-Jun;LI Yin-Shuang;WANG Zhen;LIU Jian(The 15th Research Institute of China Electronics Technology Group Corporation,Beijing 100191,China;Guangxi Key Laboratory of Cryptography and Information Security,Guilin University of Electronic Technology,Guilin 541004,China;Beijing Electronic Science and Technology Institute,Beijing 100070,China)

机构地区：[1]中国电子科技集团公司第十五研究所,北京100191 [2]桂林电子科技大学广西密码学与信息安全重点实验室,桂林541004 [3]北京电子科技学院,北京100070

出　　处：《密码学报》2023年第6期1140-1150,共11页Journal of Cryptologic Research

基　　金：广西密码学与信息安全重点实验室开放课题(GCIS201912);北京高校“高精尖”学科建设项目(20210101Z0401)。

摘　　要：SMBA是2019年全国密码算法设计竞赛胜出算法之一,软硬件实现效率高且具有较强的安全性.本文对该算法抗不可能差分分析的能力进行了新的鉴定,进行了6轮SMBA-128算法不可能差分区分器的推导和证明,比设计者给出的区分器多了1轮;基于其中1个区分器首次给出了9轮密钥恢复攻击,数据复杂度和时间复杂度分别为2^(104.2)和2^(121);基于找到的SMBA-256算法的8轮不可能差分区分器,进行了12轮密钥恢复攻击过程,数据复杂度和时间复杂度分别为2^(248.2)和2^(227.6).由此说明SMBA算法仍然具有足够的安全冗余.SMBA is one of the winning algorithms in the 2019 National Cryptographic Algorithm Design Competition,with high efficiency in software and hardware implementation and adequate security.In this paper,a new identification of the algorithm’s ability to resist impossible differential analysis is evaluated.The 6-round impossible differential distinguishers of the SMBA-128 algorithm are derived and proved,which has one more round than the distinguisher provided by the designer.Based on one of the distinguishers,a 9-round key recovery attack is given,with data complexity 2104.2 and time complexity 2121 respectively.An 8-round impossible differential distinguisher based on the newly designed SMBA-256 algorithm performs a 12-round key recovery attack procedure with data complexity and time complexity of 2248.2 and 2227.6,respectively.The results show that the SMBA algorithm still has sufficient security redundancy.

关 键 词：分组密码 FEISTEL结构 不可能差分区分器 提前抛弃技术 

分 类 号：TP309.7[自动化与计算机技术—计算机系统结构]