流密码中非线性组合函数的分析与设计

从互信息的观点出发，本文研究了非线性组合函数与其部分变量的组合之间的相关性，探讨了这种相关性对流密码安全性的影响。利用Ｗａｌｓｈ变换，分析了Ｂｅｎｔ函数与其部分变量之间的相关性，给出了一类与Ｂｅｎｔ函数有相同渐近谱特性的布尔函数的结构。

Analysis and Design of Nonlinear Combining Functions in Stream Ciphers

From the viewpoint of mutual information,correlations between a nonlinear combining function and combinations of part of its variables ae studied,and the effect of such correlations on the security of stream ciphers is investigated.Using Walsh transform, correlations between a Bent function and part of its variables are analysed,and a class of Boolean functions is introduced which hold the same asymptotic spectrum properties as Bent functions.