Abstract: The spatiotemporal chaotic system has good cryptographic properties and is often applied for Pseudorandom Number Generator（PRNG）. However, the density distribution of spatiotemporal chaotic system is not uniform, which is not good for the security of PRNG. To solve this problem, a new pseudorandom number generator based on spatiotemporal chaos is presented. To improve the cryptographic property of local map, the piecewise logistic map is used as the local map of the spatiotemporal chaos. The uniform density distribution is achieved by changing the coupled parameters of spatiotemporal chaos. The results of theory analysis and simulation test show that the sequences generated by the presented algorithm own good initial-value sensitivity and randomness. Meanwhile, the presented algorithm also has high efficiency. It can satisfy the security requirement of encrypting information.

Key words: pseudo-random generator, spatiotemporal chaos, chaos cryptography, piecewise Logistic map

摘要： 时空混沌系统有很好的密码学特性，常被用来设计伪随机数发生器。然而，时空混沌系统的概率密度分布不均匀，不利于保证伪随机数发生器的安全。针对此问题，提出一种新的基于时空混沌系统的伪随机发生器算法。该算法从提升时空混沌局部映射的密码学性能入手，将分段Logistic映射作为局部映射，并通过改变时空混沌系统的耦合参数来解决概率密度分布不均的问题。理论分析与仿真实验的结果表明，该算法产生的序列具有良好的初值敏感性和随机性，同时具有良好的执行效率，能够满足信息加密安全的需要。

关键词: 伪随机数发生器, 时空混沌, 混沌密码, 分段Logistic映射