【作者】 李海芬；

【导师】 陈在平； 董恩增；

【作者基本信息】 天津理工大学 ， 模式识别与智能系统， 2011， 硕士

【摘要】 随着计算机技术、网络技术和多媒体技术的快速发展和广泛应用,为人们获取和交流信息提供了极大的方便。然而,全透明的网络多媒体信息极易被非法分子盗版和篡改。因此,如何保护多媒体信息的安全成为国际上研究的热点问题。本文主要研究了基于DSP的混沌信号生成、基于超混沌信号的图像加密和视频加密方法,具体工作包括:1)了解混沌的概念、特征,研究了几种典型的混沌系统的动力学行为,传统的加密方法,并指出传统加密方法存在的一些问题。2)由于混沌系统在信息安全领域具有广阔的应用前景,数字混沌电路实现一直是混沌应用领域研究的热点。本文提出了一种利用DSPTMS320F2812实现三维混沌系统数字电路的方法,通过模型修改,该方法可以实现不同混沌系统的数字电路。实验结果与计算机仿真相图完全一致,证实了该方法的有效性和灵活性。3)提出了一种新的基于超混沌系统的图像加密算法,其中置乱矩阵和扩散矩阵分别由Chen混沌系统和Chen超混沌系统生成。在图像加密过程中,首先,应用置乱矩阵来扰乱原图像像素间的位置;然后,应用扩散矩阵与置乱后图像的像素值进行异或操作,以改变图像像素值,达到图像加密的目的。最后对实验结果进行分析,仿真实验证实该加密算法具有巨大的密钥空间和良好的安全性能。4)为解决视频信息的安全问题,本文提出一种基于超混沌系统的视频加密算法,该算法将流加密和块加密相结合,流加密用来产生随机序列,块加密用来置乱数据。流加密由二维离散的超混沌系统产生,块加密由超混沌系统产生。并对算法进行安全性分析,验证算法的安全性。更多还原

【Abstract】 Multimedia information has become a main way for information communication along with the rapid development and the wide use of computer, network and multimedia technology. However, the transparence of digital multimedia information over network also facilitates unauthorized copying and intentional tampering. Therefore, multimedia information security problems became a pop international research question.This paper studies based on DSP chaotic signal generation, image encryption and video encryption,The main contributions of this dissertation are:1) Studying the basic characteristics of chaos and several typical of chaotic system dynamics behavior, the traditional encryption methods, and points out that the traditional encryption methods existing problem.2) Firstly introduces chaos theory and the basic characteristics of chaos. Owing to the broad application prospect in information security field, the study of digital chaotic circuits becomes a research focus in field of chaotic engineering application. This paper presents a method of 3-D digital chaotic circuit implementation based on DSPTMS320F2812. Through modifying model, the different 3-D chaotic systems are implemented easily by using this method. The experimental results are in good agreement with computer simulation, which demonstrates the effectiveness and flexibility of proposed method.3) This paper presents a new image encryption algorithm, in this algorithm, shuffling matrix and diffusing matrix are generated based on Chen’s hyper-chaotic system. Firstly, the Chen’s hyper-chaotic system is used to shuffle the position of the image pixels, then use Chen’s hyper-chaotic system to confuse the relationship between the original image and the cipher image. The experimental results demonstrate that the encryption algorithm of image has the advantages of large key space and high security. Owing to more complex dynamical behaviors, the proposed encryption algorithm is more secure than some chaos based encryption algorithm.4) Video information to address security issues, this paper presents a hyperchaotic system based on video encryption algorithm and block cipher stream encryption combined stream cipher used to generate random sequence, block encryption to scramble data. Stream encrypted by the two-dimensional discrete chaotic system to produce ultra, block encryption generated by the super-chaotic system. And security analysis algorithm to verify security of the algorithm.更多还原