基于遍历矩阵和混合密钥的验证和图像空域加密技术

Authentication and Image Spatial Encryption Based on Ergodic Matrix and Hybrid Key System

由于图像与人感知外部世界的基本手段相吻合，因此相关的信息量有可能涉及到个人隐私、商业利益、军事机密等，所以多媒体信息的安全问题变得越来越重要。传统的加密系统，如RSA、DES、IDEA、SAFER和FEAL等，其加密速度慢而且不能有效去除相邻像素的相关性，不适合用于图像加密。经过二十多年研究的混沌加密系统具有良好的特性适合图像加密，但大部分是基于对称加密。对称加密比非对称加密速度更快，但是对于密钥的管理制约了其广泛的使用，为了弥补这一缺陷，文章提出混合密钥机制，不仅可用于图像加密，而且可用于验证。遍历矩阵在加/解密系统中不仅作为公开密钥存在，而且是图像置乱和扩散的关键参数。实验结果表明，与现有的混沌加密系统相比，文章提出的图像加密技术彻底置乱和扩散原始图像，并且拥有至少3.08＆#215;105898个密钥的巨大空间，因此足够抵制蛮力攻击。相比于现有的混沌密码系统，文章的实验测试结果更加乐观，在C语言下，置乱和扩散阶段的执行时间相当稳定（分别是1.9-2.0毫秒和2.0-2.1毫秒）。与Yang和Ismail所提出的算法相比，根据文章中的性能评估、敏感度分析和统计分析，文章所提出的算法具有更高的安全性，并且适用于网络传输。

For human being, the basic means of the perceptions of the world and the image is consistent. Therefore, the relevant information may possibly related to personal privacy, commercial interests and military secrets, so the security of multimedia information becomes more and more important. Conventional encryption systems, such as RSA, DES, IDEA, SAFER and FEAL, are not suitable for image encryption. Because of its encryption speed is slow and can not effectively remove the correlation between adjacent pixels. The chaotic encryption systems which have been studied for over twenty years have good characteristics for image encryption, but most of the systems are based on a symmetric encryption. Symmetric encryption is faster than symmetric encryption, but the key management restricts its widespread applications. In order to remedy this defect, this paper proposes a hybrid-key mechanism. It’s not only can be used for image encryption, but also can be used in verification. Ergodic matrix in the encryption / decryption system is not only to generate a public key, but also is the key parameter of image confusion and diffusion. The experimental results show that compared with the existing chaotic encryption system, the proposed image encryption technology completely shuffles and change the pixel values of the original image. More than that, it has at least a huge space of 3.08 ＊ 105898 keys, therefore it’s enough to resist the brute force attack. Compared with the existing chaotic cipher system, the experimental results in this paper are more optimistic： coded in the C language, confusion and diffusion stage of the execution time is quite stable （respectively is between 1.9 to 2 ms and 2 to 2.1 ms）. Compared with the algorithms introduced by Yang and Ismail, the proposed algorithm, according to the performance evaluation the sensitivity analysis and statistical analysis, our proposed algorithm is more secure, and is suitable for network transmission.