【作者】 唐国坪；

【导师】 廖晓峰；

【作者基本信息】 重庆大学 ， 计算机软件与理论， 2005， 博士

【摘要】 随着信息与通信技术的迅猛发展和广泛应用,网络与信息系统基础性、全局性的作用日益增强,网络信息的安全与保护问题日益成为亟待解决的关键问题。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。这一想法来自于混沌理论和传统密码学之间的自然联系:一个强的混沌系统的动力学特性大致对应着高强度密码系统的某些安全特征,而具有良好混合性的传统密码系统又暗示着拟混沌现象。从1989年Matthews和Pecora与Carroll分别提出混沌密码学中的两种方案之后,混沌密码的研究进入了繁荣时期,有大量的研究结果发表,出现了不少充满希望的进展。尽管相当数量新提出的混沌密码被攻破了,但是仍有很多直到目前尚未遇到真正有效的攻击。同时,一些设计混沌密码的系统方法已开始出现,这些方法往往对系统的安全性做了相当细致的分析,从而使这些密码算法具有较高的实用价值和安全性,如使用由混沌系统构造S盒的分组密码就是这样的例子。本文关于混沌分组密码及其应用的研究主要涉及下面三个问题:基于混沌系统的S盒设计(固定的和动态更新的S盒);基于混沌系统的不同类型的分组密码设计;混沌分组密码的在数字水印方面的应用。具体说来,本文的主要研究内容及创新之处有:1.对目前混沌密码学的发展状况进行了较详细的分析、归纳和总结,并对公开发表的混沌分组密码的分析方法进行了系统的概括,提出了目前存在的一些需要解决的关键问题。2.运用混沌系统构造高强度的S盒。在传统分组密码学中,S盒是唯一一个非线性运算部件,它的性能直接影响到整个密码系统的强度,它的设计一直是密码设计与密码分析的研究重点。由于传统分组密码中大多只公布S盒的内容,并不提供S盒的构造方法,往往给人以存在陷门的嫌疑。本文借助混沌系统的优良特性(如伪随机性、遍历性、混合性和确定性等),采用数学的方法,构造出高性能的S盒,其安全性可以通过数学分析予以证明。通过仔细分析,我们还可以运用混沌系统来构造性能同样良好的动态S盒。本论文中,不仅提出了运用混沌系统构造静态S盒和动态S盒的新方法,而且还首次提出了对S盒进行密码学特性分析的系统方法。3.在仔细分析Hénon映射特性的基础上,提出了一种将混沌系统与Feistel结构相结合设计混沌分组密码的方法,并对该方法所设计的密码算法的性能进更多还原

【Abstract】 With the rapid development and extensive applications of information and communication technology, the foundation and global role of network and information systems have been progressively strengthened. As a result, the security and protection of network information are becoming increasingly a key problem that must be solved urgently.Since 1980s, the idea of using chaotic systems to design new ciphers has attracted more and more attention. The usefulness of chaos in cryptography depends on the natural relationship between the two research areas: strong dynamical properties of chaotic systems imply strong cryptographical properties of cryptosystems, and the basic way to design cryptosystems containing good strong cryptographical properties implies quasi-chaos. The boom of research on chaotic ciphers occurred from 1989, two chaotic ciphers schemes proposed by Matthews, Pecora and Carroll, and much more contributions are made to get many promising achievements. Although a number of recently proposed chaotic ciphers have been cryptanalyzed, however, many others have not been effectively attacked yet. At the same time, some systematic ways to design chaotic ciphers have been proposed with careful considerations on the security of algorithms such as, e.g., the chaotic block ciphers based on S-boxes.This dissertation focuses on the design and application of chaotic ciphers. Generally, it can be divided into three parts: the design of S-boxes based on chaotic systems (fixed or dynamic S-box), the design of various block ciphers based on chaotic systems, and the application in digital watermark of chaotic ciphers. Specifically, the main achievements and originality contained in this dissertation are as follows:1. The research status and advances of chaotic ciphers has been summarized, analyzed and overviewed. The analyzing method of chaotic block cipher has been expatiated in detail, and several existent key problems to be solved urgently have been pointed out.2. The problem how to utilize chaotic systems to construct cryptographically strong S-boxes has been studied. In traditional block cipher, the S-box is the only one nonlinear core component and it determines the strength of these cryptosystems. Therefore, the construction of cryptographically strong S-boxes is of much更多还原