【作者】 李守鹏；

【导师】 何德全；

【作者基本信息】 四川大学 ， 应用数学， 2002， 博士

【摘要】 信息技术发展到今天，铸就了以各种网络环境，特别是Internet为基础的信息社会。空间因之而缩小，时间因之而缩短，人们的交流方式因之而改变，而便捷。信息社会正在改变着人们的观念，改变着和优化着人类的生存方式。它既是人类知识与智慧的丰富源泉，又是人类精神生活的广阔舞台。然而，明天，明天我们还能奢望今天我们所拥有的这一切吗?非常幸运，自从信息技术发展之初，人们就开始注意到了信息安全问题。经过不断的研究和探索，已经积累了大量的解决信息基础设施安全的宝贵方法和经验，最终形成了今天还依然在不断发展和完善的“信息保障”概念和方法。信息保障降低了安全风险，增强了我们对明天的信息社会的信心。本文的目的是研究与信息保障密切相关的信息安全的有关问题。第一章对信息保障的历史进行回顾，介绍在信息保障的发展历程中有关信息安全的概念和方法，如：引用监视器(RM)、引用确认机制(RVN)、可信计算基(TCB)、安全模型、TCSEC、CC、IATF、FRITSA等。第二章分析信息安全的时空特性。从空间上讲信息安全表现为信息设施的纵向层次化、横向上地域分布、结构上异构的特点。从时间上讲信息安全表现为信息存在的不同的状态和时间特性以及信息系统设施存在的不同生命期阶段特性。信息可能处于产生、存储、处理、传递和使用几种不同的状态，信息系统设施的生命期一般包括开始、建造、安装实现、评估、运行维护和废弃几个阶段。从时空特性出发，可更为系统地研究信息安全的方方面面问题。第三章研究信息安全最基础的理论问题，即信息安全模型。在考察BLP模型的基础上，指出它的局限性，并对BLP模型加以推广，给出系统的一般安全定理。注意到当今网络时代信息系统的高度分布和开放的复杂特点，本章采用安全域划分的方法，研究了各种 四 川 大 学 博 士 学 位 论 文复杂程度的系统的安全性。系统安全的关键是安全政策必须完备、正确且一致，并得到正确实施。因此，本章详细讨论了系统安全政策，从政策的正确性、完备性、一致性、粒度、到多样性，并且给出了一种政策的一致性检查算法。为全面了解信息保障，第四章首先简要介绍了信息保障技术框架 （f ATF），然后针对我国信息技术发展的特殊性，提出了为常规保障技术所忽视的“特种保障”问题和技术，并且围绕着恶意功能的作用方式，深入研究了恶意功能的检测和防范方法。这种恶意功能防范方法的研究正是特种保障方法研究之所在。为了对信息安全给予客观的评价，第五章在介绍目前最为流行的信息技术安全评估通用准则（CC）及其配套的信息技术安全通用评估方法比E回）的基础卜，提出了一套信息安全综合评估方法。该方法以模糊综合评价为主，局部采用加权平均，是信息技术安全评估的新思路。第六章是全文的结论，指出本文的不足及值得进一步研究的问题。 本文的意义在于：它总结了信息安全的时空特性；给出了一个一般化的安全模型，并对安全政策进行了深入探讨；提出了“特种保障”概念，并展开了分析和研究；以综合评价方法为信息安全评估开辟了新思路。更多还原

【Abstract】 Nowadays with the developmeot of infOrmation technology, The informationsociety which is founded on the variety of networks environrnent, especia1ly theInternet has been constructed. Space is reduced. Time is shortened. The ways ofinteraction between people are changed and made convenient. The infOrmationsociety has been changing the notion of the people, changing and optimizing thefashion of living of human beings. It is not only a rich source of Anowledge andwisdom, but also a wide stage of the mental life of mankind. But tomorroWtomorrow could we wish extravagantly all of these.Quite fOrtUnate1y, since the very beginying of the dcvelopment of theinformation technOlogy, people haVe noticed the problem of information security.Through condrious stUdy and eXPloring, large ainountS of valuable approachesand experiences used to solve the problem of security of infOrmationinfrastructures have been accumulated. And eventually the concept and method of"information assurance (IA)" which has been ever developing and imProving isestablished. Information assurance has lowered the risk of security and increasesthe confidence for tomorrow’s information societyThe pmpose of this paper is to stUdy the relevant problems pertain toinformation security Whick is closely related to information assurance. The firstchapter gives a retrospect of the brief history of the IA. The conc9PtS andaPproaches relating to information security among the course of development ofthe IA are introduced. For examPle, Reference Monitor (are), ReferenceValidation Mechanism (RVM), Trusted ComPuting Base (TCB), security model,TCSEC, CC, IATF FRITSA, etc. ChaPter 2 analyzes the time and space prOPerty’ of infOrmation security. ln space, information security demonstrates the propertyof the information infrasmicture that layered in vertical, distributed in horizontaiand heterogeneous in strUctuTe and comPosition. In time, information security’demonstrate the property of the existence of information in differefit states andtime as well as the different life cycle stages of the information system.InfOrmation might in one of the different states of generation, storage, processing,transmitting and usage. The life cycle of information systems usually containsinitiation, consmiction, deployInent, evaluation, opefation and abandonmentstages. Steding off from the time-space property all aspects of infOrmationsecurity can be stUdied systematically. ChaPter 3 studies the most fundamentaltheoretical issues of information security i.e. the stUdy of information securitymodels. Based on the examination of the Bell and LaPudula (BLP) model, thelimitation of the model is indicated, and the model is expanded. A general theoremof systCm security has been put forward. In view of the highly distributed andopening characteristics of information systems in netWork times today, thischaPter emPloys a method of security domains separation to stUdy the security ofsystems of various kinds of degree of complexity The key for information systemsecurity is that the system security policies must be comPlete, correct andconsistent, and be enforced properly So the security policy is also discussed indetail in this chaPter, from policy correctness, fullness, consistency, granularity, topolicy variety. And an algorithm for checking the consistency of the policies isgiven. In order to fully understand the IA, chaPter 4 first gives a brief introductionof the "InfOrmation Assurance Technical Framework (IATF)", and then accordingto the speciaity of the development of China’s information technology a "specialassurance" prob1em and technology that is often ignored by the normal "IA"technoiogy is brought forward. And based on the ways that a hostility functionmay acts, the methods used to detect (test) and prevent these functions are studied.The stUdy of the preventon measures for these kinds of hostility functions isexactly the task of the stu更多还原