Abstract: Chaos is widely used in image encryption because of its high sensitivity to initial conditions and parameters and its stochastic series. A kind of chaos map whose parameters were randomly changed was brought forward. A chaos key stream with good randomcity and long cycle was made out, whose statistic character was proved strictly. The key stream has been used to encrypt image, and method was proved to work well.

Key words: chaos, image encryption, piecewise linear chaos map, chaos degradation

摘要： 由于混沌系统对初始条件和混沌参数非常敏感,以及生成的混沌序列具有非周期性和伪随机性的特性,近年来在图像加密领域得到了较多的应用。提出了一种基于参数随机变化的混沌映射的密码生成方法,生成一个随机性好,长周期的密钥序列并给出了统计特性分析的严格的理论证明。用此序列进行图像加解密实验,对结果分析表明提出的算法能够得到令人满意的加密效果。

关键词: 混沌, 图像加密, 一维线性映射, 混沌退化