摘要
目的针对基于位平面信息量分布的选择性加密算法安全性不高、像素置换加密算法不能很好抵抗统计攻击问题,提出一种基于位级同步置乱扩散和像素级环形扩散的图像加密算法(BSPDPAD算法),提高图像加密效率和安全性。方法 BSPDPAD算法首先通过分段线性混沌映射产生两组混沌序列,其中一组混沌序列对图像进行随机分块,另一组混沌序列分解到位平面构成位级密钥流;然后,将各像素块分解到位平面,利用位级密钥流同步置乱扩散高位平面、置乱低位平面,实现位平面上块内置乱扩散及块间扩散;最后,再次迭代分段线性混沌映射产生新的密钥流,利用该密钥流对经过位级加密的中间密文图像进行横向顺序扩散和纵向逆序扩散,完成图像加密。结果灰度图像及彩色图像上的计算机仿真实验与性能分析表明:BSPDPAD算法密钥空间大于2^(100),信息熵接近于8,密文图像直方图趋近于均匀分布;与其他加密算法相比,BSPDPAD算法密文图像相邻像素相关性系数绝对值减小约1~2数量级,像素变化率和归一化平均强度明显提高,说明BSPDPAD算法在密钥、明文敏感性、抵抗多种攻击能力等性能上优于其他加密算法,且算法扩散效果好,仅一轮加密就能获得较理想的加密效果。结论将位级选择性加密与像素级环形扩散相结合的BSPDPAD算法可有效抵抗各种攻击,安全性高,适合各种类型的灰度及彩色图像加密,潜在应用价值大。
Objective With the rapid development and popularity of the Internet and information technologies,computers and mobile phones have become an important part of the daily lives of people. Through these electronic devices,a large number of pictures that may contain private information are transmitted and stored. Image information security is becoming increasingly important. However,the use of traditional encryption algorithms（ e. g.,data encryption standard,advanced encryption standard,and international data encryption algorithm） to encrypt images will result in low efficiency and poor se-curity because of the data size and high redundancy among the pixels of digital images. An effective approach to deal with this issue is to develop secure and effective digital image encryption algorithms. The existing image algorithms can be categorized into pixel-permutation-based,chaotic-system-based,and bitplane-based methods. The image encryption algorithms of the pixel-permutation-based method change the pixel position to destroy adjacent pixel dependencies by performing the permutation operation on the pixel matrix,thereby generating noise-like and meaningless cipher images. However,only the encryption algorithms that use pixel permutation have weak resistance to statistical attacks and poor security. The image encryption algorithms of the chaotic-system-based method take advantage of the excellent intrinsic properties of a chaotic sequence,such as ergodicity,pseudorandomness,and sensitivity to initial conditional and control parameters,to enable diffusion and confusion encryption. These methods have a large key space,strong keystream adaptivity,and high security and often combine with other encryption methods to achieve effective image encryption. The image encryption algorithms of the bitplane-based method decompose the pixels into bit levels,implementing the permutation and diffusion operations on the bitplanes. Bitplane matrix transformation,selective encryption based on bitplane information distribution,and integrati
作者
梁颖
张绍武
Liang Ying;Zhang Shaowu(Key Laboratory of Information Fusion Technology of Ministry of Education, School of Automation, NorthwestPolytechnical University, Xi＇an 710072, China)
出处
《中国图象图形学报》
CSCD
北大核心
2018年第6期814-826,共13页
Journal of Image and Graphics
基金
国家自然科学基金项目(61473232,91430111)
关键词
位级
同步置乱扩散
环形扩散
分块
图像加密
bit-level
synchronous permutation-diffusion
annular diffusion
blocking
image encryption
