Abstract: Recursive diffusion layer is a new type of cryptographic linear diffusion layer. It has good structure characteristics,and can achieve the optimal effect of diffusion layer. It is more complex in the concrete implementation process because its function structure parameters in the search space is large. It seriously impacts on its cryptographic function in the actual application ability. After analyzing the structure and the lower order based on the structure of the diffusion layer,and combining with the optimal diffusion layer of relevant theoretical basis,this paper gets some general conclusions of recursive diffusion layer,and based on this,it gives a method to design the recursive diffusion layer and puts forward a scheme to improve the coefficient’s implementation of recursive diffusion layer. By the simulation realization,it gets the results of recursive diffusion layer’s structure in low order. The diffusion layer only needs a few XOR operation, rotating operations and some simple complementation operations,and it has a better security character.

Key words: linear diffusion layer, recursive diffusion layer, branch number, linear function, weight coefficient, simulation realization

摘要： 递归扩散层是一种新型的密码函数线性扩散层,具有良好的结构特征,能达到最优扩散层的效果,但其构 造函数中的参数比较复杂,搜索空间也较大。为此,对递归扩散层的结构特点进行分析,从低阶扩散层的结构出 发,结合最优扩散层的相关理论基础,得到递归扩散层的一般性结论,在此基础上设计权值系数计算方法,并通过 仿真实现得到部分低阶递归扩散层的构造函数。分析结果表明,该方法构造的扩散层只需要少数的XOR 运算、旋 转运算和简单的求反运算,满足最优扩散层的性质,具有较好的安全特性。

关键词: 线性扩散层, 递归扩散层, 分支数, 线性函数, 权值系数, 仿真实现

CLC Number: 

• TP309