An Overview of Computer security
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paper_title: Password security: a case history

paper_content:

This paper describes the history of the design of the password security scheme on a remotely accessed time-sharing system. The present design was the result of countering observed attempts to penetrate the system. The result is a compromise between extreme security and ease of use.
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paper_title: Cryptography and data security

paper_content:

From the Preface (See Front Matter for full Preface) ::: ::: Electronic computers have evolved from exiguous experimental enterprises in the 1940s to prolific practical data processing systems in the 1980s. As we have come to rely on these systems to process and store data, we have also come to wonder about their ability to protect valuable data. ::: ::: Data security is the science and study of methods of protecting data in computer and communication systems from unauthorized disclosure and modification. The goal of this book is to introduce the mathematical principles of data security and to show how these principles apply to operating systems, database systems, and computer networks. The book is for students and professionals seeking an introduction to these principles. There are many references for those who would like to study specific topics further. ::: ::: Data security has evolved rapidly since 1975. We have seen exciting developments in cryptography: public-key encryption, digital signatures, the Data Encryption Standard (DES), key safeguarding schemes, and key distribution protocols. We have developed techniques for verifying that programs do not leak confidential data, or transmit classified data to users with lower security clearances. We have found new controls for protecting data in statistical databases--and new methods of attacking these databases. We have come to a better understanding of the theoretical and practical limitations to security.
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paper_title: An Experience Using Two Covert Channel Analysis Techniques on a Real System Design

paper_content:

This paper examines the application of two covert channel analysis techniques to a high level design for a real system, the Honeywell Secure Ada® Target (SAT). The techniques used were a version of the noninterference model of multilevel security due to Goguen and Meseguer and the shared resource matrix method of Kemmerer. Both techniques were applied to the Gypsy Abstract Model of the SAT. The paper discusses the application of the techniques and the nature of the covert channels discovered. The relative strengths and weaknesses of the two methods are discussed and criteria for an ideal covert channel tool are developed.
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paper_title: Abstract data types and software validation

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A data abstraction can be naturally specified using algebraic axioms. The virtue of these axioms is that they permit a representation-independent formal specification of a data type. An example is given which shows how to employ algebraic axioms at successive levels of implementation. The major thrust of the paper is twofold. First, it is shown how the use of algebraic axiomatizations can simplify the process of proving the correctness of an implementation of an abstract data type. Second, semi-automatic tools are described which can be used both to automate such proofs of correctness and to derive an immediate implementation from the axioms. This implementation allows for limited testing of programs at design time, before a conventional implementation is accomplished.
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paper_title: A penetration analysis of the Michigan Terminal System

paper_content:

The successful penetration testing of a major time-sharing operating system is described. The educational value of such a project is stressed, and principles of methodology and team organization are discussed as well as the technical conclusions from the study.
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paper_title: Password security: a case history

paper_content:

This paper describes the history of the design of the password security scheme on a remotely accessed time-sharing system. The present design was the result of countering observed attempts to penetrate the system. The result is a compromise between extreme security and ease of use.
---

Title: An Overview of Computer Security

Section 1: THREATS
Description 1: This section discusses various threats to computer security, including password guessing, spoofing, user browsing, Trojan horses, denial of service attacks, exhaustion of shared resources, and statistical database inferences.

Section 2: THREAT CLASSIFICATION
Description 2: This section attempts to categorize the various threats into specific types such as browsing, leakage, inference, tampering, accidental data destruction, masquerading, and denial of service.

Section 3: PROTECTION MECHANISMS
Description 3: This section introduces protection mechanisms used to enhance computer security, grouped into authentication mechanisms, access control, and inference control. It also covers penetration analysis, formal verification techniques, and covert channel analysis.

Section 4: CONCLUSIONS
Description 4: This section provides a brief overview and summarizes the topic of computer security, encouraging the reader to refer to other comprehensive sources for a more detailed study.