摘要
目的当前很多图像加密都采用基于比特的加密算法。针对这种比较流行的加密算法所存在的安全缺陷问题,提出一种能够解决比特面0比特和1比特置乱时的位置限制的图像加密算法,实现比特的全局重组。方法首先利用Tent混沌映射生成一个伪随机序列,然后利用生成的伪随机序列对比特明文图像进行整行以及整列的置乱,将置乱后的比特像素矩阵分块分别进行Henon映射的置乱,最后经过扩散操作得到最后的密文图像。结果加密后明文图像的像素值的分布由不均匀变成了均匀分布,明文图像的各像素间的相关性被打破,使得原图没有了统计特性,像素变化率(NPCR)以及归一化平均变化强度(UACI)皆接近理想值,算法能够抵抗穷举攻击和差分攻击,并且在能保证加密安全的同时能有较低计算复杂度。结论本文所提出的图像加密算法具有加密后像素相关性低、密钥空间大,以及对明文图像和密钥高度敏感等特点,本文算法在进行比特级的置乱时,又加入了与明文相关的特性,增强了加密算法的明文敏感性,同时也加强了加密算法的扩散性,可有效地保障密文图像的安全。
Objective Many of the current image encryption algorithms are based on bit level,whichhave security flaws.Many bit-based image encryption algorithms divide the plain-text image into eight-bit planesaccording the eight binary pixels,and then scramble the eight bit planes,which results in 0 bits and 1 bits of each bit plane to not change,onlymakingthe position change of the 0bit and 1bit in each into bit plane,so that there are security flaws.In this paper,a new image encryption algorithm was proposed according to the existing problems of security flaws in these popular encryption algorithms.The proposed algorithm can resist the chosen-plaintext and the chosen-ciphertext attacks,and solve the position restriction of 0bit and 1bit in the bit plane to bring about global reconstruction.Method The scrambling of the image encryption algorithm is divided into two stages：the first stage of the scrambling is to be transformed into a binary pixel matrix for global scrambling;the second stage of the scrambling is to block the pixel matrix after the global scrambling and scramblefor each bit plane.First,the Tent chaotic map is used to generate a pseudo-random sequence.Then,each pixel of the plain-text image is converted into binary bits,andpseudo-random numbers are sorted in ascending order to generate a new set of sequences.For example,in any sequence {0.3,0.7,0.5,0.4,0.8,0.2},the sequence is sorted in ascending order to obtain the ordered sequence {0.2,0.3,0.4,0.5,0.7,0.8},and then the corresponding position sequence is {6,1,4,3,2,5}.The new sequence is used to carry out the whole row and column scrambling.The pixel matrix is divided into eight blocks to perform the Henon map scrambling,and then the final cipher image is obtained by the diffusion operation.Result The distribution of the pixel value of the plain-text image after encryption changes from non-uniform to uniform distribution,and the correlation between the pixels of the plain-text image is broken.Thus,the original image has no statistical characteristics,the n
出处
《中国图象图形学报》
CSCD
北大核心
2017年第10期1348-1355,共8页
Journal of Image and Graphics
基金
国家科技支撑计划项目(2013BAB06B04
2016YFC0400910
2017ZX07104001)
中央高校基本科研业务费专项基金项目(2015B22214
2017B16814)~~
