基于可变参数双向耦合映像系统的时空混沌Hash函数设计

在分析单向与双向耦合映像格子系统的初值与参数敏感性的基础上，提出了一种基于可变参数双向耦合映像系统的时空混沌单向Hash函数构造方案.该方案以耦合映像系统的部分初态作为密钥，在迭代过程中, 通过上一次的迭代值和线性变换后的不同位置的明文消息比特动态确定双向耦合映像系统模型参数，将明文消息多格点并行注入时空混沌轨迹中；取迭代序列中最后一轮迭代结果的适当空间项，线性映射为Hash值要求的128 bit值.由于耦合映像系统的双向扩散机理与混乱作用，迭代过程具有极强的不可逆性及初值与参数敏感性，Hash结果的每位都与明文及密钥有着敏感、复杂的非线性强耦合关系.仿真实验与分析结果表明，该算法达到了Hash函数的各项性能要求，安全性好，执行效率高. 关键词： Hash函数 时空混沌 耦合映像格子

A TCML-based spatiotemporal chaotic one-way Hash function with changeable-parameter

A TCML-based spatiotemporal chaotic one-way Hash function with changeable parameter was constructed based on the analysis of sensitivity to initial value and parameters of one-way and two-way coupled map Lattice(TCML)systems.The approach is implemented by employing part of the initial values of coupled map system as the secret key,and the parameters of two-way coupled map system in each iteration is dynamically determined by the value of the last iteration and the corresponding message bit in different positions,and then making message with multigrid embedded in spatiotemporal chaos track in parallel.Choosing some suitable spatial items of the result of the final iteration,the Hash value was obtained by means of linear transform limited with 128 bits.Iteration process has very strong irreversibility and sensitivity to initial values and parameters.Each bit of Hash value has very sensitive,complex and strongly nonlinear coupling relation with the corresponding message and secret key because of the bidirectional diffusion and confusion characteristics.Simulation and analysis demonstrate that the algorithm satisfies all the performance requirements of Hash function and is reliable,secure and efficient.