利用一类具有偶对称特性的一维分段线性映射 ,提出了时变参数混沌滚动密钥产生器的构造方法 ,所产生的模拟混沌序列的相空间分布不包含局部的线性结构 ,其密钥序列也具有理想的密码学特性 By using a class of one-dimensional piecewise linear mapping with even symmetry, a method for constructing the chaotic rolling key generator with time-varying parameters is proposed. The phase space distribution of the simulated chaotic sequences does not include the local linear structure. The key Sequences also have ideal cryptographic properties