轻量级分组密码Pyjamask的不可能差分分析

Pyjamask是美国国家技术标准研究院征选后量子时代轻量级密码算法中进入第二轮的候选分组密码,对其抵抗现在流行的不可能差分分析分析为未来在实际系统中使用起到重要的作用.提出一些2.5轮不可能差分链并分析它们的结构特点和攻击效率,在一些最有效的不可能差分链的前后各接1轮和半轮,形成4轮Py-jamask多重不可能差分攻击路径.攻击结果表明Pyjamask的行混淆运算扩散性比较强,能较好地抵抗不可能差分分析,此结果是对Pyjamask安全性分析的一个重要补充.

Impossible differential cryptanalysis of lightweight block cipher Pyjamask

Pyjamask is the second-round candidate for the NIST lightweight cryptography selection. In order to use it in the practical system safely, it is very important to analysis its security against the popular attacks. This paper studied the security of Pyjamask against impossible differential cryptanalysis. Specifically, it constructed several 2.5 rounds of impossible differentials and studied their structures'' properties and the attacking efficiency. By appending one round at the top and half a round at the bottom of some effective impossible differentials, it proposed two 4-round multiple impossible differential attacking paths. The results show that Pyjamask can resist against impossible differential cryptanalysis effectively because it has a very powerful diffuse operation MixRows. Meanwhile, these results are important supplements for the security of Pyjamask.