引言在基于代替—置换(S—P)网的秘密密钥密码体制中(如:DES类体制),密码体制的强度直接取决于算法所用的S-盒(代替盒)的质量。最近在关于差分密码分析的论文中指出:如果使用性能较差的S-盒,那么,DES密码能够被破译。因此,好的S-盒设计是设计一个DES类型密码体制的一个重要组成部分。为了设计出好的S-盒,我们在本文中提出一组基于信息论的扩充准则,它由九条设计准 INTRODUCTION The strength of cryptosystems in S-P based secret key cryptosystems (eg, DES class systems) directly depends on the quality of the S-box (instead of the box) used in the algorithm. In a recent paper on differential cryptanalysis, it was pointed out that if a poorly performing S-box is used, the DES password can be deciphered. Therefore, a good S-box design is an important part of designing a DES-type cryptography. In order to design a good S-box, we propose in this paper a set of expansion rules based on information theory, which consists of nine design criteria