王高丽　　　甘　楠

1(华东师范大学计算机科学与软件工程学院　上海　200062)

2　　　(东华大学计算机科学与技术学院　上海　201620)

(glwang@sei.ecnu.edu.cn)



对8轮mCrypton-96的中间相遇攻击

王高丽1,2甘楠2

1(华东师范大学计算机科学与软件工程学院上海200062)

2(东华大学计算机科学与技术学院上海201620)

(glwang@sei.ecnu.edu.cn)

A Meet-in-the-Middle Attack on 8-Round mCrypton-96

Wang Gaoli1,2and Gan Nan2

1(SchoolofComputerScienceandSoftwareEngineering,EastChinaNormalUniversity,Shanghai200062)

2(SchoolofComputerScienceandTechnology,DonghuaUniversity,Shanghai201620)

AbstractmCrypton is a lightweight block cipher introduced in Information Security Application 2006 by Lim and Korkishko. mCrypton-6496128 denote 3 versions of the cipher with 6496128 b keys respectively. In this paper, we apply the meet-in-the-middle (MITM) attack on 8-round mCrypton-96, which improves the best MITM attack result on mCrypton-96 by 1 round.When analyzing the security of block ciphers, using key relations to reduce the time complexity, memory complexity and data complexity is a common method. From the property of the key schedule of mCrypton-96, we know that each round key could calculate some information of the internal register by the algebraic structure of the key schedule, and some round keys could be deduced from the other round keys. By using the relationship of key schedule and the properties of S-box, we present a MITM attack on 8-round mCrypton-96 based on the 4-round distinguisher by adding 1 round on the top and 3 rounds at the bottom. The time, memory and data complexities of the attack are 293.5encryptions, 247B and 257chosen plaintexts respectively. It is illustrated that mCrypton-96 not only has an efficient performance but also possesses strong security.

Key wordscryptanalysis; meet-in-the-middle (MITM) attack; block ciphers; mCrypton; relationship of keys

摘要在分析分组密码算法的安全性时，利用密钥关系来降低时间、存储和数据复杂度是一个常用的手段.在4轮mCrypton-96性质的基础上，利用密钥生成算法的弱点和S盒的性质，降低了攻击过程中需要猜测的密钥比特数，提出了对8轮mCrypton-96算法的中间相遇攻击，攻击的时间复杂度约为2(93.5)次8轮mCrypton-96加密运算，存储复杂度为2(47)B，数据复杂度为2(57)个选择明文.

关键词密码算法分析；中间相遇攻击；分组密码；mCrypton；密钥关系

分组密码算法在现代密码学中有着举足轻重的地位，1997—2000年美国高级加密标准(advance encryption stand, AES)算法征集活动大大促进了分组密码算法的设计和分析.继美国新一代加密算法标准确定之后，欧洲、日本和韩国等多国都开始各自征集密码算法标准，这将分组密码的分析和设计推向了一个高潮.最近，轻量级分组密码算法由于它的密钥关系更简单、使用的电脑硬件资源更少、加密速度优于一般的分组密码算法而广泛用于资源受限的环境，如射频识别卡(radio frequency identification, RFID)和嵌入式环境.轻量级分组密码算法LED，Zorro，mCrypton，PRESENT，Piccolo，Klein，XTEA，DESL，HIGHT，CLEFIA，Twine，KATAN，轻量级流密码算法Grain和Trivium，以及基于PRESENT 的轻量级杂凑函数等算法的出现大大促进了轻量级密码的发展.与此同时，出现了许多对于轻量级分组密码算法的……