Mysterion算法的不可能差分分析

Impossible Differential Cryptanalysis of Mysterion

Mysterion算法是XLS设计策略的具体实例,该算法的主要目的是改进LS设计策略,在不影响实现效率的前提下提升LS设计策略的安全性。文章采用不可能差分分析方法对Mysterion算法进行安全性分析,首先证明了Mysterion算法的结构不可能差分轮数最长为4轮,然后利用S盒的信息,突破了Mysterion的结构不可能差分上界,通过优化搜索算法得到5轮的算法不可能差分。Mysterion算法的最大不可能差分轮数比LS设计策略的代表算法Robin算法多1轮,从不可能差分的角度证明了XLS设计策略的安全性要弱于LS设计策略。

The Mysterion block cipher is a specific example of the XLS-designs,the main purpose of this algorithm is to improve the LS-designs and enhance the security of LS design strategy without affecting the implementation efficiency.Impossible differential cryptanalysis is applied to analyze Mysterion.Firstly,it proves that the truncated impossible differential of the Mysterion algorithm is upper bounded by 4 rounds.Then,using the information of the S-box breaks through the upper bound of truncated impossible differential of Mysterion and manages to get 5-round impossible differential.The Mysterion’s maximum round of impossible differential is one more than the Robin algorithm,which is the representative algorithm of LS-designs.From the perspective of impossible differential,the security of XLS-designs is weaker than LS-designs.