Akelarre分组密码算法的奇偶校验分析

Parity Check Analysis of Akelarre Block Cipher Algorithm

Akelarre分组密码算法的圈函数和循环移位操作使其输入输出的奇偶性保持不变,明文和密文间存在一个形式简单的关系式,从而降低算法安全性。为此,提出一种可对任意轮数的Akelarre分组密码算法进行攻击的奇偶校验分析方法。结果表明,该方法在穷举量约为241时,能恢复出输入输出变换的子密钥信息以及密文对应的明文信息。

In Akelarre block cipher algorithm,circle function and cycle shift operation makes the same parity input and output,and exists a form of simple equation between expressly and cipher text,it reduces algorithm security.Aiming at the design weakness,this paper presents an improved parity check attack which can apply to any round of the algorithm to Akelarre by employing the weakness.Result shows that this method can obtain the sub-keys and the corresponding plaintexts when the computing complexity of the improving attack is about 241.