General Information


Matt Bishop
telephone, (916) 752-8060; email,; WWW,;
Office, 3059 Engineering Unit II; Office hours: MWF1:10-2:00PM Pacific Coast time, or by appointment
Note: If you send me email, please mark the header as ECS 253 - URGENT to help me see it quickly!


MWF 2:10 - 3:00PM in Room 1062, Banier Hall

Course Outline

Elements of cryptography and data security; system security, and network security. Both theory and applications will be covered, but theory will be emphasized.

Course Goals

Some goals we hope you achieve:
  1. learn the importance of computer security;
  2. understand the basics of the theory behind cryptography;
  3. understand how to use cryptography in support of security services;
  4. learn the basic theory and practise of secure systems;
  5. understand the types of security services needed for network security; and
  6. analyze or survey some aspect of computer security and cryptography in depth.


Edward Amoroso, Fundamentals of Computer Security Technology, Prentice-Hall, Englewood Cliffs, NJ 07632 (1994). ISBN 0-13-108929-3.

Computer Programs

The homework assignments, and your project, may require computer programs. Any computer programs written for this class must be well documented, cleanly written, and have a manual page or write-up describing how to use it, its input, and its output. Include sample runs. If you have C or C++ available, I would prefer you use one of those; if not, any reasonable computer language is fine.

Course Web Page, Handouts, and Newsgroup

The web page contains links to all course handouts (except for the published/copyrighted papers). They will also be available for anonymous ftp at /pub/cs253.

Because we have some students without access to the UC Davis campus newsgroups, information about this class, homework assignments, office hours, and so forth, will be posted to the web page as well as to the ucd.class.ecs253 newsgroup. Read this newsgroup (or web page) daily, especially near the time assignments are due. You are responsible for everything posted. This newsgroup is not for discussion about the class, but information from the instructor to you.

If you want to post things about the class, please use the discussion newsgroup ucd.class.ecs253.d, or send the instructor a mail message asking that something be posted. Discussing something in this group is perfectly fair!

Postings from both newsgroups will be copied to the web page regularly.


There will be 5 homework assignments. The due date will be on each assignment.I will try to have your homework graded as quickly as possible, usually within three class periods after I receive it.

Because this is a graduate class, we'll begin with no penalty for late homework. (I reserve the right to change this if I feel students are falling behind.) This class covers a lot of material very quickly, and if you delay you will probably fall too far behind to catch up easily. So don't delay - do the homework on time!

Some general notes: if you handwrite your homework, please write legibly. If I can't read your answer, or understand it, it's wrong. Please think your answers through before writing them down in final form; a request for a proof requires a proof, not a statement that "it's probably right, and here are 15,000 examples to show it;" a request for a discussion should be treated as an essay question, with a main theme and arguments for and against the answer. It is fair to present the factors that affect your answer; it is not acceptable to begin by giving one answer in the introduction and a different answer in the conclusion! (Yes, you'll lose points.) And, always show your work; if you simply write down a correct answer and do not show how you got that answer, you will not get any credit.


This class requires a term project requiring you to do outside reading, or apply what we've learned in class to a realistic situation, or extend your knowledge beyond what is done in class. The project is an integral part of the course, because it demonstrates you've learned enough to go beyond what we talked about in class.

The handout Projects describes the requirements in some detail and suggests possible projects, as well as the required intermediate reports.

Penetration Analysis Project

I would like students to get a feel for some of the uses to which computer securty can be put. As part of this, the class will conduct a penetration analysis of a computer system. More information will be given on the first Friday of class.


Each day, some student will be a scribe, to take notes. When you do this, send me the notes (in ASCII or latex(1); write out any equations in a form the reader can understand). I will review them and then post them to the web page for everyone's use.


UCD Students: 40% Homework 40% Project 20% In-Class Participation
NTU Students: 50% Homework 50% Project
The Participation points come from two sources. Half (10%) come from scribing. The other half (10%) come from the Penetration reports. Because of the week's delay in getting access to the class tapes, NTU students will not be scribing and may choose not to participate in the Penetration Analysis Project. More details on opting into the latter will be available during the first week of class.

Note that there are no exams.

Recommended Reading

  1. Dorothy Denning, Cryptography and Data Security, Addison-Wesley ©1984
    Perhaps the best computer security text written so far; its only problem is being very out of date. Much of the cryptography is drawn from this book. If you can get a copy of it, I strongly encourage you to do so; it's a wonderful text.
  2. Helen Fouch» Gaines, Cryptanalysis: a Study of Ciphers and their Solution, Dover Publications, ©1956.
    A classic on cracking transposition and substitution ciphers, it does not cover more modern cryptography, but it shows the basics of cryptanalysis in a non-mathematical way.
  3. Simpson Garfinkel and Gene Spafford, Practical UNIX and Internet Security, O'Reilly & Associates, ©1996.
    A marvelous book on UNIX security. Don't look for deep principles here; this book is a practicum.
  4. Morrie Gasser, Building a Secure Computer System, Van Nostrand Reinhold, ©1985
    "The" book for practical and theoretical considerations in the design of a secure computer system. Not too rigorous, but quite comprehensive.
  5. Katie Hafner and John Markoff, Cyberpunk, Simon & Schuster, ©1991.
    This book describes three of the better-known computer security incidents and the people behind them. It's not too technical, but a good study of hackers.
  6. Lance J. Hoffman, Rogue Programs: Viruses, Worms, and Trojan Horses, Van Nostrand Reinhold, ©1990.
    A collection of papers about malicious programs; the section on social and legal issues is very interesting,
  7. David Kahn, The Codebreakers, Second Edition, Macmillan ©1996.
    Truly a classic, this book combines history with some basic cryptanalysis to show the evolution of codes and ciphers. This is the unabridged version, recently updated and re-released.
  8. Alan Konheim, Cryptography: A Primer, John Wiley and Sons ©1981.
    Probably the best book yet on cryptanalysis; it does not have as much depth as Meyer and Matyas' book on some subjects (such as the DES), but it is much broader in scope. Beware of the notation, though: this can be a very hard book to understand!
  9. Carl Meyer and Stephen Matyas, Cryptography: A New Dimension in Computer Data Security, John Wiley and Sons, ©1982.
    A very complete study of modern cryptography; the chapter on the DES is excellent.
  10. National Research Council, Computers at Risk: Safe Computing in the Information Age, National Academy Press, ©1991.
    A study of how national policy should reflect problems, and advances, in computer security.
  11. Donn Parker, Crime by Computer, Charles Scribner's Sons ©1976.
    Good discussion of what can happen if you ignore security considerations; it also considers ethics, something rarely seen but very badly needed.
  12. Wayne Patterson, Mathematical Cryptography for Computer Scientists and Mathematicians, Rowman and Littlefield, ©1987.
    Highly mathematical, up-to-date treatment of many ciphers. Watch out for typographical errors and switches in notation, though!
  13. Bruce Schneier, Applied Cryptography, Second Edition, John Wiley and Sons, ©1996.
    This book is a good but nonrigorous introduction to cryptography. The first edition had loads of errors, but (I am told) this version has eliminated most of them.
  14. Abraham Sinkov, Elementaty Cryptanalysis: A Mathematical Approach, The Mathematical Association of America, ©1966.
    A readable yet mathematical account of substitution and transposition ciphers.

Academic Integrity

Please see pages 148-149 of the Spring 1997 Class Schedule and Room Directory for a general discussion of this. In particular, for this course:

A good analogy between appropriate discussion and inappropriate collaboration is the following: you and a fellow student work for competing software companies developing different products to meet a given specification. You and your competitor might choose to discuss product specifications and general techniques employed in your products, but you certainly would not discuss or exchange proprietary information revealing details of your products. Ask the instructor for clarification beforehand if the above rules are not clear.


#DateTopic, Readings, and Other Information
1.Monday, March 31Introduction to Computer Security
Reading: text, §1, §2, §8.2;
M. Bishop, "Computer Security," unpublished
2.Wednesday, April 2The Role of Cryptography and Basic Information Theory
Reading: text, §20.1
3.Friday, April 4Penetration Studies: Foundations
We will discuss the structure of a penetration study, go through a couple of examples, and begin planning our exercise.
Reading: text, §3;
M. Bishop, "Vulnerabilities Studies," unpublished
4.Monday, April 7Number Theory and Transposition Ciphers
Reading: text, §20.3
5.Wednesday, April 9Substitution Ciphers and Their Analysis
6.Friday, April 11Penetration Studies: Flaw Hypothesis Methodology
This is the basis for penetration studies; we will explore it using UNIX examples.
Reading: text, §5;
R. R. Linde, "Operating System Penetration," AFIPS National Computer Conference, AFIPS, Arlington, VA pp. 361-368 (1975).
7.Monday, April 14Product Ciphers and the DES
Reading: text, §20.4;
The Data Encryption Standard, FIPS PUB 46 (Jan. 1977);
M. E. Hellman, "DES Will Be Totally Insecure Within 10 Years," IEEE Spectrum 16(7) pp. 32-39 (July 1979); including rebuttals by W. Tuchman, G. Davida, and D. Branstad
8.Wednesday, April 16Public Key Cryptography, the Knapsack Cipher, the RSA Cipher
Reading: text, §21.5;
W. Diffie, "The First Ten Years of Public-Key Cryptography," Proceedings of the IEEE 76(5) pp. 560-577 (May 1988);
R. Rivest, A. Shamir, and L. Adleman, "A Method for Obtaining Digital Signatures and Public-Key Cryptosystems," Communications of the ACM 21(2) pp. 120-126 (Feb. 1978).
9.Friday, April 18Penetration Studies: Reports #1, From the Outside
Each team will have 5 minutes to present the techniques it tried, what was learned, and what should be tried next
10.Monday, April 21No class
11.Wednesday, April 23No class
12.Friday, April 25Penetration Studies: Vulnerabilities Models
We will discuss the Program Analysis project, RISOS, Aslam's classification, and the Davis security model.
Reading: C. E. Landwehr, A. R. Bull, J. P. McDermott, and W. S. Choi, "A Taxonomy of Computer Program Securty Flaws," Computing Surveys 26(3) pp. 211-254 (Sep. 1994).
13.Monday, April 28Authentication, One-Way Hash Functions
Reading: text, §18 and §19;
R. Morris and K. Thompson, "Password Security: A Case History," Communications of the ACM 22(11) pp. 594-597 (Nov. 1979).
14.Wednesday, April 30Key Management, Certificates
Reading: text, §21.8-9;
S. Kent, "Privacy Enhancement for Internet Electronic Mail: Part II: Certificate-Based Key Management," RFC 1422 (Feb. 1993).
15.Friday, May 2Penetation Studies: Reports #2, From the Inside
Each team will present the techniques it tried, what was learned, and what should be tried next.
16.Monday, May 5Limits of Security
The HRU result; the Take-Grant Protection Model; limits of decidability
Reading: M. A. Harrison, W. L. Ruzzo, and J. D. Ullman, "Protection in Operating Systems," Communications of the ACM 19(7) pp. 461-471 (Aug. 1976);
L. Snyder, "Formal Models of Capability-Based Protection Systems," IEEE Transactions on Computers C-30(3) pp. 172-181 (Mar. 1981).
17.Wednesday, May 7Lattice Models; Models of Confidentiality
Bell-LaPadula Model, tranquility, System Z and the debate
Reading: text, §6-§7, §9-10;
J. McLean, "A Comment on the `Basic Security Theorem' of Bell and La Padula," Information Processing Letters 20(2) pp. 67-70 (Feb. 15, 1985);
L. La Padula, "The `Basic Security Theorem' of Bell and La Padula Revisited," unpublished
18.Friday, May 9Penetation Studies: Analysis
Implementation vs. design flaws, effects, how to limit damage, how to prevent introduction
Reading: text, §25
19.Monday, May 12Models of Integrity
Lipner's Access Matrix Model, Biba, Clark-Wilson
Reading: text, §12-13;
S. B. Lipner, "Non-Discretionary Controls for Commercial Applications," Proceedings of the 1982 IEEE Symposium on Security and Privacy pp. 2-10 (Apr. 1982);
D. Clark and D. Wilson, "A Comparison of Commercial and Military Computer Security Policies," Proceedings of the 1987 IEEE Symposium on Security and Privacy pp. 184-194 (Apr. 1987).
20.Wednesday, May 14Hybrids and Standards
Chinese Wall, Orange Book, ITSEC
Reading: text, §29;
D. Brewer and M. Nash, "The Chinese Wall Security Policy," Proceedings of the 1989 IEEE Symposium on Security and Privacy pp. 206-214 (May 1989).
21.Friday, May 16Penetration Studies: Reports #3, Fixing the Flaws
Each team will present an analysis of the flaws uncovered, and how they would fix them and/or prevent their introduction
22.Monday, May 19Policy and Modelling Issues
Nondeducibility, noninterference, composition of policies and the Hook-Up Theorem
Reading: text, §11, §24
D. McCullough, "Specifications for Multi-Level Security and a Hook-Up Property," Proceedings of the 1987 IEEE Proceedings on Security and Privacy pp. 161-166 (Apr. 1987).
23.Wednesday, May 21Access Control Mechanisms
Access Control Matrix, ACLs, Capabilities; levels of privilege, ring-based control
Reading: text, §22
Ko, Hai-Ping, "Security Properties of Ring Brackets," Proceedings of the Computer Security Foundations Workshop II, pp. 41-46 (June 1989).
24.Friday, May 23Penetration Studies: Intrusion Detection
How to detect exploitation of flaws; logs, auditing, real-time vs. post mortem analysis
Reading: text, §16-17;
D. Denning, "An Intrusion Detection Model," Proceedings of the 1986 IEEE Symposium on Security and Privacy pp. 118-131 (Apr. 1986).
25.Monday, May 26Memorial Day — University Holiday
26.Wednesday, May 28Access Control Mechanisms (con't)
Mandatory and Discretionary Controls, Origination Control
27.Friday, May 30Security Kernels
Principles, trusted path, covert channels, principle of layering, verification; discussion of examples
Reading: text §26;
P. Karger, M. Zurko, D. Bonin, M. Mason, and C. Kahn, "A Retrospective on the VAX VMM Security Kernel," IEEE Transactions on Software Engineering SE-17(11) pp. 1147-1165 (Nov. 1991).
28.Monday, June 2Network Security Basics
Authentication protocols, ISO model and its relationship to security
Reading: text, §27;
V. L. Voydock and S. T. Kent, "Security Mechanisms in High-Level Network Protocols," Computing Surveys 15(2) pp. 135-171 (June 1983).
29.Wednesday, June 4Network Security Analysis
Analysis of a network protocol (PEM or NTP) using the Internet Security Architecture
Reading: M. Bishop, "A Security Analysis of the NTP Protocol, Version 2," Proceedings of the Sixth Annual Computer Security Applications Conference pp. 20-29 (Dec. 1990).
30.Friday, June 6Penetration Studies: Reports #4, Detecting the Intruder
Each team will present a report on the intrusion (if any), what they did to detect the intruder, and what the attacker did once in.
Reading: L. T. Heberlein, K. Levitt, and B. Mukherjee, "A Model to Detect Intrusive Activity in a Networked Environment," Proceedings of the Fourteenth National Computer Security Conference pp. 362-371 (Oct. 1991).


Why a Project?

This course covers a very large discipline, and - perhaps more so than many other areas of computer science - the discipline of computer security runs through many other areas. Because the class has a very limited amount of time, we will only touch the surface of many topics. The project gives you an opportunity to explore one of these topics, or some other area or application of computer security that interests you, in some depth.

Suggestions for How to Proceed

First, choose a topic. Good ways to find a topic are to think about an area of computer science you enjoy, and try to relate it to computer security (or vice versa); talk to some other graduate students and see if what they are doing suggests any ideas; think of ways security of the system you're working on could be made better; go to the library and browse for an interesting-looking paper; and so forth. The major computer security journals are Computers & Security and Journal of Computer Security, but articles appear in almost all journals; the major conferences are Crypto and Eurocrypt (for cryptography), Symposium on Research in Security and Privacy, National Computer Security Conference, and the Annual Computer Security Applications Conference. If you need more help or have questions, feel free to talk to me.

This term, you may also use the penetration study as your project (see below). If you do this, you will need to turn in a final report as well as the interim reports and presentations (if you are not on campus, don't worry about the presentations).

Some Suggestions for Project and Report Topics

What Is Due When

Friday, April 25 By this time you should have chosen your project. Turn in a 2-3 page writeup of what you want to do, and why; list several sources, and describe how you plan to go about completing the project. For example, if you are writing a survey paper, state the theme and in general terms how you will organize your paper.
Wednesday, May 14 By this time your project should be well underway. Turn in a 3-4 page description of what you have done, approaches that you took and that failed, and so forth. For example, for a survey paper, turn in a brief description of what your references contain, and present a detailed outline of your paper.
Friday, June 6 Your completed project is due.

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Department of Computer Science
University of California at Davis
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