基于二维可逆非线性映射的图像加密算法

根据一类二维可逆非线性映射具有单值确定的逆、本质非线性以及运算简单等适合构造密码算法的特点,提出适用于图像加密的新算法.将图像分成若干块,每块采用二维可逆非线性映射对各像素点的灰度值进行链式循环迭代,二维非线性映射的参数与迭代次数由一维混沌映射产生.克服了序列密码中存在的错误扩散问题,解决了由计算机精度引起的解密失败难题.安全性与复杂度的理论分析和仿真结果表明:该算法具有很高的密码学强度,简单、快速,特别适合于大数据量的图像加密工作.

Image Encryption Algorithm Based on Chaos System Two-dimensional Reversible Non-linear Maps

Because a kind of two-dimensional reversible non-linear maps have single definite reverse and essential non-linear characteristic with simple operation,it is suitable for applying these maps in image encryption.Take Henon map for example,a new fast image encryption algorithm applying these maps is presented.At first the picture is divided into several in this algorithm.Then,Henon map is utilized to circularly iterate gray value of pixels by chain type.Iterated times and parameter of Henon map are set as a chaotic sequence generated by one-dimensional chaotic maps.It not only overcomes shortcoming that the mistake spreads but also solves difficult problem of deciphering failure because of limited precision in computer.Analyze indicates that this kind of algorithm has very high security.This algorithm is designed simply and the computational speed is fast,so it is suitable to be applied in encrypting image of great data volume.