Cryptanalysis of Full-Round Magpie Block Cipher  

作　　者：YANG Yunxiao SUN Bing LIU Guoqiang 

机构地区：[1]College of Liberal Arts and Sciences,National University of Defense Technology,Changsha 410073,China [2]State Key Laboratory of Cryptology,P.O.Box 5159,Beijing 100878,China [3]State Key Laboratory of Information Security,Institute of Information Engineering,Chinese Academy of Science,Beijing 100093,China [4]Hunan Engineering Research Center of Commercial Cryptography Theory and Technology Innovation,Changsha 410073,China

出　　处：《Chinese Journal of Electronics》2023年第2期217-224,共8页电子学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(61772545,61702537,62002370);State Key Laboratory of Information Security(2020-MS-02).

摘　　要：Magpie is a lightweight block cipher proposed by Li et al.in Acta Electronica Sinica volumn 45,issue 10.It adopts an substitution-permutation network(SPN)structure with a block size of 64 bits and the key size of 96 bits,respectively.To achieve the consistency of the encryption and decryption,which is both hardware and software friendly,16 bits of the key are used as control signals to select S-boxes and another 16 bits of the key are used to determine the order of the operations.As the designers claimed,the security might be improved as different keys generate different ciphers.This paper analyzes the security of Magpie,studies the difference propagation of Magpie,and finally finds that the cipher has a set of 280 weak keys which makes the full-round encryption weak,and corrects the lower bound of the number of active S-boxes to 10 instead of 25 proposed by the designers.In the weak key model,the security of the cipher is reduced by the claimed 280 to only 4×2^(16).

关 键 词：Block cipher Differential cryptanalysis Weak key Active S-boxes MAGPIE 

分 类 号：TN918.4[电子电信—通信与信息系统]