对8轮CLEFIA算法的一种现实攻击

摘要

CLEFIA算法是SONY公司在2007年的快速软件加密大会上提出的一个分组密码算法.研究了CLEFIA算法的等价结构,并找到了它的一个5轮区分器.基于5轮区分器,利用中间相遇攻击方法对6/7/8轮的CLEFIA算法进行了攻击.攻击复杂度都比较小,其中对于6轮和7轮的攻击在普通PC机上不到1秒钟就可恢复密钥,8轮的攻击在高性能计算机上也是可以实现的.%CLEFIA is a block cipher proposed in FSE (Fast Software Encryption) 2007 by SONY Corporation. Some 5-round distinguishes of CLEFIA are presented according to study an equivalent structure of CLEFIA. Based on the 5-round distin-guishers,some meet-in-the-middle attacks can be made on 6/7/8-round CLEFIA. The attack complexities are low enough and the key of 6/7-round CLEFIA can be recovered within one second in the ordinary PC. Moreover,the 8-round attack can be also implemented in the high-performance computer.