基于混沌的数字彩色图像加密及软硬件实现

发布时间：2019-06-21 08:11

【摘要】：伴随着因特网的日益普及,图像、语音、视频等多媒体数字化信息的交流己越来越具有开放性、自由性和国际性,从而出现了各种各样的信息安全问题。对于数字图像信息而言,由于其数据量大、冗余性高及相关性强等特点,使得以往普通的加密方法并不适用。随着对混沌理论研究的发展和深入,发现混沌理论与密码学之间有着强烈的对应关系,混沌密码技术为数字图像等多媒体信息的安全提供了新的解决方案。本文基于混沌系统所具有的类随机性、宽频谱、对初始状态及结构参数的极端敏感性等一系列特性,考虑数字彩色图像数据的特点并结合密码学的特性与要求,设计并实现了一种基于高维广义超混沌猫映射的数字彩色图像加密算法。该算法首先是对原始数字彩色图像的R、G、B分量进行编排处理,然后对处理后的图像采用二维广义猫映射置乱图像像素位置和八维广义猫映射扩散像素值,交替进行数轮置乱与扩散过程后,再对图像进行拆分整合得到加密图像。这种高维广义猫映射存在两个正的李指数,属于超混沌映射,能进一步改善置乱和扩散效果,再加上对数字彩色图像的R、G、B分量的编排处理,大大提高了图像加密的安全性。为了说明所设计的算法应用于数字彩色图像加密的性能,本文通过MATLAB软件对图像加解密算法进行仿真实现并对算法的密钥空间、图像的统计特性(包括直方图和相邻像素的相关性)及密钥的雪崩效应等进行了测试和分析,验证了算法的可行性、安全性和保密性。本文利用芯片型号为TMS320DM6437的DSP开发平台,对数字彩色图像的加解密算法进行了相关的测试,给出了DSP硬件实现的结果及加解密所需的时间,验证了该算法的实用性和实时性。
[Abstract]:With the increasing popularity of the Internet, the exchange of multimedia digital information, such as image, voice, video and so on, has become more and more open, free and international, resulting in a variety of information security problems. For digital image information, because of its large amount of data, high redundancy and strong correlation, the previous ordinary encryption methods are not suitable. With the development and deepening of chaos theory, it is found that there is a strong corresponding relationship between chaos theory and cryptography. Chaotic cryptography provides a new solution for the security of multimedia information such as digital images. Based on a series of characteristics of chaotic system, such as randomness, wide spectrum, extreme sensitivity to initial state and structural parameters, considering the characteristics of digital color image data and combining with the characteristics and requirements of cryptography, a digital color image encryption algorithm based on high-dimensional generalized hyperchaotic cat mapping is designed and implemented in this paper. The algorithm first arranges and processes the R, G and B components of the original digital color image, and then uses two-dimensional generalized cat mapping to scramble the pixel position of the image and the eight-dimensional generalized cat mapping diffusion pixel value. After several rounds of scrambling and diffusion, the image is split and integrated to obtain the encrypted image. This kind of high-dimensional generalized cat map has two positive lie indices, which belong to hyperchaotic mapping, which can further improve the scrambling and diffusion effect. In addition, the arrangement and processing of R, G and B components of digital color image greatly improves the security of image encryption. In order to illustrate the performance of the designed algorithm in digital color image encryption, the image encryption and decryption algorithm is simulated by MATLAB software, and the key space of the algorithm, the statistical characteristics of the image (including the correlation between histogram and adjacent pixels) and the avalanche effect of the key are tested and analyzed, and the feasibility, security and confidentiality of the algorithm are verified. In this paper, the encryption and decryption algorithm of digital color image is tested by using the DSP development platform of chip model TMS320DM6437. The results of DSP hardware implementation and the time required for encryption and decryption are given, and the practicability and real-time performance of the algorithm are verified.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TP309.7

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