导　　师： 朱志良

学科专业： 081201

授予学位： 硕士

作　　者： ;

机构地区： 东北大学

摘　　要： 随着计算机科学理论以及网络技术的不断发展和普及,使得数据量巨大的多媒体信息在全世界范围内获得了极其广泛的应用。但是由于数字信息易于拷贝和发布,存在很多安全隐患,由此对信息安全与信息保护的研究人员提出了巨大挑战。为了迎接这样的挑战,维护信息的安全性及可靠性,人们提出了各种各样的加密方案和技术。 密码学是保护信息安全的基本手段。混沌系统具有许多密码系统所期待的良好性质,如对初始条件和控制参数的敏感性、周期点集的稠密性和拓扑传递性等。经过研究证明,这些性质与密码学中的混淆与扩散特性有着密切的关系,因此,基于混沌的密码技术在信息安全方面具有重要的地位。此外,一个性能优良的的传统密码系统又通常显示出混沌的某些现象。因此,基于混沌的密码技术很快成为了信息安全领域的又一研究热点,起着越来越重要的作用。 自二十世纪80年代以来,应用混沌系统构造新型密码系统受到了越来越多的关注。从1989年Matthews、Peeora和Carroll分别提出混沌密码学中的两种方案之后,混沌密码技术的研究进入了繁荣时期,取得了大量的研究成果,出现了不少充满希望的进展。然而,近期的研究表明,原来提出的某些被认为是实用性强和安全性高的混沌密码方案被证实为是效率低、不安全和不可用的。如何通过细致的分析,设计混沌密码方案日渐成为急待解决的问题。 本文重点研究了基于混沌理论的多媒体信息加密技术,主要工作有以下几个方面: /(1/)详细论述了混沌理论基础。首先指出混沌现象普遍存在于自然科学和社会科学的诸多领域,回顾了混沌理论的研究历史,然后给出了混沌的定义,描述了混沌运动的特征。接着介绍了混沌研究所需的判据与准则,最后简要概括了混沌理论的广阔的应用前景� With the development of computer technology and network, the multimedia information including image and video is widely used all around the world. Meanwhile, some safety problems in information exchange are presented as this kind of information is easily to copy and to distribute. The research on information safety and protection is significant in all fields of our society. There are a lot of superior characters of chaotic system, for example, the sensitivity of initial condition and control parameters, and the cryptosystem based on chaotic theory has played a significant role in information security. Furthermore, it has been proved that there is a great relationship between classic cryptosystem and chaos based cryptosystem. To begin with, the keys in both cryptosystem are sensitive. Secondly, the confusion and diffusion operations are performed during encryption phase. Last but not least, a well designed classic cryptosystem always show some chaotic feathers which always be seen in chaotic system. As these reasons, more and more researchers have concentrate on the research on the cryptosystem based on chaotic system. A lot of researches on chaos based cryptosystem are reported after Matthews, Peeora and Carroll who firstly present the two strategies of the encryption algorithm which is based on chaos in 1989. In the passed decades, it has become a good candidate for real security applications and has become a special and significant branch in this field. In this paper, the following works are introduced. /(1/) Detail the basic knowledge of chaos theory. Firstly, the phenomenons of chaos widely exist in many fields of our nature science and society science. Secondly, the history of chaos is reviewed and the two kinds of definition of chaos are presented. Last, the criteria of chaos and its application in the research are suggested. /(2/) The modern cryptosystems are detailed in Chapter 2 and the great relationship between classic cryptosystems and chaotic cryptosystem are suggested.

关 键 词： 混沌理论 加密技术 多媒体 图像加密 视频加密

领　　域： [电子电信] [电子电信]