一类分组密码变换簇抵抗线性密码分析的安全性评估

线性密码分析是针对分组密码的强有力的攻击方法,估计分组密码抵抗线性密码分析的能力是分组密码安全性评估的重要内容之一.基于实际应用背景,提出了"四分组类CLEFIA变换簇"的概念,并利用变换簇中两种特殊分组密码结构的线性逼近之间的关系,给出了变换簇中所有密码结构抵抗线性密码分析的安全性评估结果,并提出了需要进一步探讨的若干问题.这种利用变换簇对分组密码进行研究的方法,为分组密码的安全性评估提供了一个较为新颖的思路.

Security Evaluation Against Linear Cryptanalysis for a Class of Block Cipher Transform Cluster

Linear cryptanalysis is a powerful attack on block ciphers.To evaluate the security against linear cryptanalysis is one of the most important part for the security evaluation of block ciphers.In this paper,the concept of four-block CLEFIA-like transform cluster is put forward based on the background of practical application.Using the relation between linear approximations of two special block cipher structures,security evaluation against linear cryptanalysis for all block cipher structures of the cluster is given.Moreover,some open problems are given.We provide a novel idea for the security evaluation of block ciphers by using transform cluster to study block ciphers.