This paper presented a new self-adaptive image encryption algorithm so as to improve its robustness. Under this algorithm, a gray image or color image was divided into 2 × 2 size blocks. A corresponding size of matrix in the top right comer was created by the pixel gray-scale value of the top left comer under Chebyshev mapping. The gray-scale value of the top right comer block was then replaced by the matrix created before. The remaining blocks were encrypted in the same manner in clockwise until the top left corner block was finally encrypted. This algorithm is not restricted to the size of image and it is suitable to gray images and color images, which leads to better robustness. Meanwhile, the introduction of gray-scale value diffusion system equips this algorithm with powerful function of diffusion and disturbance.%为了提高图像加密算法的鲁棒性,提出了一种新的自适应图像加密算法.首先,把任意大小的灰度或彩色图像分成2×2子块;然后,用左上角子块的像素灰度值和Chebyshev混沌映射构造与右上角子块等大的矩阵,用该矩阵对右上角子块进行像素灰度值替换;最后,按顺时针对每个子块进行加密,直到左上角子块加密完毕.该算法不依赖于图像的大小,而且适用于灰度图像和彩色图像,因而有很强的鲁棒性.同时灰度值扩散机制的引入使得该算法具有良好的扩散性和扰乱性.
展开▼
