对特殊类型Feistel密码的Square攻击  

Square Attack on Some Special Feistel Ciphers

作　　者：张鹏[1] 孙兵[1] 李超[1,2] 

机构地区：[1]国防科技大学理学院,湖南长沙410073 [2]信息安全国家重点实验室,北京100190

出　　处：《国防科技大学学报》2010年第4期137-140,149,共5页Journal of National University of Defense Technology

基　　金：国家自然科学基金资助项目(60803156);信息安全国家重点实验室开放基金资助项目(01-07)

摘　　要：对轮函数为SP结构的两类特殊类型Feistel密码抗Square攻击的能力进行了研究。通过改变轮函数中P置换的位置从而给出了此类Feistel密码的等价结构,以SNAKE(2)和CLEFIA为例,给出了基于等价结构Square攻击的具体过程,将6轮SNAKE(2)的Square攻击的时间复杂度由224降为213.4;将6轮CLEFIA的Square攻击的时间复杂度由234.4降为212.4。结果表明,在设计轮函数为SP结构的Feistel密码时,必须充分考虑等价结构对算法抗Square攻击的影响。Securities of two special Feistel ciphers with SP-structured round functions against Square attack were studied. By changing the position of P permutation of the round functions in an equivalent manner,some new cryptanalytic results of round-reduced SNAKE（2） and CLEFIA were presented. Time complexity of Square attack against 6-round SNAKE（2） was reduced from 224 to 213.4,and for 6-round CLEFIA,time complexity of Square attack was reduced from 234.4 to 212.4. The results show that,in designing Feistel ciphers with SP-structured round functions,influence of equivalent structures and Square attack should be taken into consideration.

关 键 词：Feistel密码 SQUARE攻击 等价结构 SNAKE(2) CLEFIA 

分 类 号：TN918[电子电信—通信与信息系统]