Civino et al. have characterised diffusion layers that expose an SPN to vulnerability from differential cryptanalysis when employing alternative operations coming from groups isomorphic to the translation group on the message space. In this study, we present a classification of diffusion layers that exhibit linearity in parallel alternative operations for ciphers with 4-bit s-boxes, enabling the possibility of an alternative differential attack simultaneously targeting all the s-boxes within the block. Furthermore, we investigate the differential behaviour with respect to alternative operations for all classes of optimal 4-bit s-boxes, as defined by Leander and Poschmann (2007). Our examination reveals that certain classes contain weak permutations w.r.t. alternative differential attacks, and we leverage these vulnerabilities to execute a series of experiments.

翻译：Civino等人已刻画了在采用与消息空间上平移群同构的群中替代运算时，暴露SPN结构易受差分密码分析攻击的扩散层特征。本研究针对采用4比特S盒的密码系统，给出了在并行替代运算中呈现线性特征的扩散层分类，使得同时对块内所有S盒实施替代差分攻击成为可能。进一步地，我们依据Leander与Poschmann（2007年）定义的分类标准，研究了所有最优4比特S盒类别在替代运算下的差分行为特性。实验表明，特定类别中存在对替代差分攻击脆弱的弱置换，我们利用这些脆弱性实施了一系列验证实验。