基于混沌的图像空域复合加密方法的研究

混沌动力系统是一种确定性非线性系统，具有类随机行为。利用其良好的伪随机性、轨道的不可预测性和混沌系统对初始状态及结构参数的极端敏感性等诸多优点，可以构造出良好的图像信息加密系统。提出了一种新的图像加密算法，利用两种混沌映射，分别对图像像素进行灰度置乱和位置置乱。实验和分析结果表明，此种算法在加密速度上有所提高并且对明文变化具有一定的敏感性，使得抵抗已知明文攻击的能力有了一定的提高，加密效果令人满意。

Research on Image Compound Encryption Method based on Chaos

Chaotic power system is a kind of deterministic nonlinear system and has random-like behavior.Based on chaotic systems with good properties such as pseudo-random,unpredictability of evolution of its orbits and extreme sensitivity on their initial condition and system parameter,a good system with image encryption is presented.In this paper,a new image encryption method is proposed,using two kinds of chaotic mapping,the encryption process disturbs grey values of each image point and array of the original image.The results of experiments and analyses show that encryption speed is improved and this method is sensitive to the change of plaintext to a certain extent.And its ability against plaintext attack is improved and encryption effect is satisfactory.