This thesis is divided into three parts:

Part I, Security Problems in Today’ s Information Systems

This part introduces the security problems and methods of protections in today’s information systems and summarizes the vulnerabilities of present protection systems.

Chapter 1, Information Systems, presents the concept of information, information system and computing system, as well as of information networks and Internet.

Chapter 2, Misuse of Information Systems describes how the information systems can be attacked.

Chapter 3, Programmed Threats, describes some of the most frequent programmed attacks

Chapter 4, Protection of Information Systems, describes methods of protection, prevention, non-adaptive protection systems and adaptive automated protection systems as ultimate protection solutions in today’s information systems.

Chapter 5, Vulnerabilities of Present Protection Systems, provides an overview of the vulnerabilities of today’s protection systems and inherent security holes in today’s information systems.

Chapter 6, Summary and Conclusions of the Part I, gives the short summary and conclusions of the first part.

Part II, Building Secure Information Systems

This part looks at the ways how to build future information systems so to obtain maximum security.

Chapter 7, What is Secure Information System?, presents the semantic definition of information, discusses what is secure information and gives the definition of secure information system.

Chapter 8, An Architecture for Intelligent Security Systems, introduces the concept and the architecture of an intelligent security system.

Chapter 9, Modeling an Expert System, introduces the theoretical model for the expert system of an intelligent security system.

Chapter 10, Implementing an Intelligent Security System, presents the prototype of an intelligent security system.

Chapter 11, Building Secure Information Systems, describes the ways for building secure information systems with an intelligent security system. Some other aspects of information security, such as human interface and privacy protection, are briefly introduced.

Chapter 12, Summary and Conclusions of the Part II, gives the short summary and conclusions of the second part.

Part III, Summary, Conclusions and further Work,

This part contains only one chapter (Chapter 13) which gives a summary and conclusions of the thesis as well as directions for further work.

Bibliography contains a listing of resources used for this thesis.

Appendix A – Glossary of Used Terms

Appendix B – Prevention Methods

Appendix C - Source Code of Prototype Nisan<