CS f361: Summer I, 2014
Introduction to Computer Security

Instructor: Dr. Bill Young

Unique number: 90155
Class time: MTWTF 10--11:30am; Location: CLA 0.130
Office: GDC 7.810; Office Hours: Tues, Wed, Fri 10-11:30am, and by appointment
Office Phone: 512-471-9782; Email: byoung@cs.utexas.edu

TA: Zhao Song; Email: zhaos@utexas.edu
TA Office Hours: Wed. 8-10am, GDC 4.818F
Proctor: Jimmy Lin; Email: JimmyLin@utexas.edu
Proctor Office Hours: Tues and Thurs 3-5pm, GDC 1.302 TA station 1
This website: www.cs.utexas.edu/users/byoung/cs361/syllabus361.html

Important Class Announcements:

Breaking news important to the class will be posted here. Consult this spot often.

Here are the statistics for the midterm: Midterm stats.

I won't be holding my usual office hours the week of July 7. But I will be in the office MWF from around 4:30-6pm. I am coming from meetings off campus, so can't promise to be here exactly at 4:30pm, but plan to arrive no later than 5pm.

Our final exam is Friday, July 11, from 7-10pm in ART 1.102. Here's the sample final: Sample Final, and tentative vocabulary list: Vocabulary. This sample is not very representative of the test you'll be given; your test has more short answer questions and very few "essay" type questions. Here are the answers to the sample final: answers. The final will be cumulative. You can bring two 3 5 index cards of material to the exam. The vocabulary sheet will be made available with the exam.

I doubt this will cause you any grief, but the Quest system will be down on Sunday, July 13th, from 7am to noon for maintenance. Hopefully, you'll be through with everything by then.

Also, the slides and questions for Weeks 4 and 5 are now all available below, along with the last programming assignment. Since the questions for week 5 and the final program are due on the last day of class, there won't be any slip days for them.

To submit your questions (in ascii text or pdf format), use the following command on the CS Linux machines (requires a cs login):

 turnin --submit jimmylin cs361_hw1 file-name(s)
Note that the second week, you'll use the same command except make it hw2, etc. At the top of each week's homework, please include the following information:
CS Login:

For programming assignment 1, please use the following command:

turnin --submit zhaos cs361_prog1  ...
For the second assignment, change to cs361_prog2, etc.

Programming assignment 4 is now available. It's to implement AES-256. Note that it's due on Thursday, July 3, because Friday is a holiday. I'd suggest getting a jump on this one because it's rather lengthy. This site contains a nice animation of AES-128: AES, but be aware that there are differences between AES-128 and AES-256, primarily in the key expansion algorithm. Also, one of the steps in the algorithm is the mixColumns step. I'd suggest trying it on your own. But if you can't get it, an implementation is here: mixColumns. There is no penalty for using this, but you must say in your README file that you did so.

Course Description:

CS 361 is an introduction to topics in computer security, one of the "hottest" and most relevant areas of computing today. The student will develop an intuition about what computer security means, both in the abstract and in the context of real systems; be able to recognize potential threats to confidentiality, integrity and availability; be aware of some of the underlying formalisms and technologies that attempt to address these challenges; and be conversant with current security-related issues in the field.

Topics to be covered will include:

  1. Scope of the security problem;
  2. Various views of computer security;
  3. Security policies;
  4. Formalizing security properties;
  5. Elementary information theory;
  6. Elementary cryptography;
  7. Cryptographic protocols;
  8. Authentication;
  9. Risk assessment;
  10. Malicious logic;
  11. System evaluation and certification.
Very important: This course has a new, blended format as of Fall, 2011. "Blended" means that a large portion of the course content is delivered on-line. Videotaped mini-lectures will be made available on-line via UT's Quest system: Quest system. You will view these prior to coming to class and answer a series of questions on-line. The class will meet twice a week, on Monday and Thursday. Both are mandatory. We'll meet to discuss the material and assignments, and possibly have a short quiz to ensure that you've viewed the lectures and done the required preparation.

We'll also have two exams, both of which will be held on a Friday. The schedule of meeting dates for the semester is here: Class Dates.

Note: This is not a self-paced course. A chart of the material for each week is here: Log of lectures. You must view the mini-lectures and do the on-line portions as they are assigned, and you must attend class on the days we meet. You will have 5-6 programming assignments over the course of the semester. If you don't have the self-discipline to keep up, you shouldn't take this course. A paper that describes the blended course is available here: Blended class

Using Piazza: We will be using Piazza for class communication. The Piazza system is highly catered to getting you help quickly and efficiently from classmates, the TA, and myself. Rather than emailing questions to the teaching staff, I encourage you to post your questions on Piazza. If you have any problems or feedback for the developers, email team@piazza.com. The Piazza class page will be posted shortly.

InfoSec Certification: Notice that CS students at UT have the option of completing a number of security-related courses and receiving a government-sanctioned certification in security. See the following link for information: Security certification.


You are expected to have taken and passed the following courses (or equivalent) with a grade of at least C-: Computer Science 311, 311H, 313H, or 313K; Computer Science 314, 314H, 315, or 315H; Computer Science 310, 310H, 429, or 429H; and Mathematics 408C, 408K, or 408N. If you don't have the prerequisites, be sure to clear it with the CS department or risk being dropped from the class.


There is no textbook. If you would like a book for reference purposes, ask me and I can suggest one. All of the lectures, slides, and supplementary materials are on-line. Note that there is a required fee for the use of the Quest system. This is very cheap compared to the cost of a textbook.

Fee for Quest System:

This course makes use of the web-based Quest content delivery system maintained by the UT College of Natural Sciences. Go to Quest system to log in to the Quest system for this class. This service requires a charge per student for its use, which goes toward the maintenance and operation of the resource. At some point during the semester, when you log into Quest you will be required to pay via credit card on a secure payment site. You may have the option to wait some time to pay while still continuing to use Quest for your assignments. But, at some point, you will be kicked off the system and not able to continue in our course; so be sure to pay up. If you are taking more than one course using Quest, there is a maximum Quest fee per semester you will have to pay. For payment questions, email quest.fees@cns.utexas.edu.

Class Notes:

All of the class slides will be available via links below. They will be made them available as we cover new material and you are welcome to print them out or view them on-line. Slides are available in 4-up PostScript (PS) or in PDF format (full size and in 4-ups). The PostScript files can be viewed with Ghostview or printed on any postscript-compatible printer. The PDF files can be viewed with Acroread.

A listing of the lectures for each week is here: Log of lectures. Slides are grouped into lectures, which are grouped into modules. Each week, you will cover several modules. Note that you must view the video associated with each lecture. It is not adequate to just read the slides.

Week 1: Module 1:

Lecture 1: Introduction PS-4up  PDF-4up  PDF

Lecture 2: Why Security is Hard PS-4up  PDF-4up  PDF

Lecture 3: Security as Risk Management PS-4up  PDF-4up  PDF

Lecture 4: Aspects of Security PS-4up  PDF-4up  PDF

Week 1: Module 2:

Lecture 5: Policies and Metapolicies PS-4up  PDF-4up  PDF

Lecture 6: A Policy Example: MLS PS-4up  PDF-4up  PDF

Lecture 7: MLS Example: Part II PS-4up  PDF-4up  PDF

Lecture 8: MLS Example: Part III PS-4up  PDF-4up  PDF

Lecture 9: MLS Example: Part IV PS-4up  PDF-4up  PDF

Lecture 10: Tranquility and BLP PS-4up  PDF-4up  PDF

Week 1: Module 3:

Lecture 11: Access Control Policies PS-4up  PDF-4up  PDF

Lecture 12: Lattice Based Security PS-4up  PDF-4up  PDF

Lecture 13: Covert Channels I PS-4up  PDF-4up  PDF

Lecture 14: Covert Channels II PS-4up  PDF-4up  PDF

Lecture 15: Covert Channels III PS-4up  PDF-4up  PDF

Lecture 16: Detecting Covert Channels PS-4up  PDF-4up  PDF

Week 2: Module 4:

Lecture 17: Non-Interference PS-4up  PDF-4up  PDF

Lecture 18: Non-Interference II PS-4up  PDF-4up  PDF

Week 2: Module 5:

Lecture 19: What is Integrity? PS-4up  PDF-4up  PDF

Lecture 20: Modeling Integrity PS-4up  PDF-4up  PDF

Lecture 21: Modeling Integrity: Biba PS-4up  PDF-4up  PDF

Lecture 22: Biba's Other Models PS-4up  PDF-4up  PDF

Week 2: Module 6:

Lecture 23: Lipner's Model PS-4up  PDF-4up  PDF

Lecture 24: The Clark-Wilson Model PS-4up  PDF-4up  PDF

Lecture 25: The Chinese Wall Policy PS-4up  PDF-4up  PDF

Lecture 26: Role-Based Access Control PS-4up  PDF-4up  PDF

Lecture 27: Storing the ACM PS-4up  PDF-4up  PDF

Week 2: Module 7:

Lecture 28: Information Theory PS-4up  PDF-4up  PDF

Lecture 29: Information Content PS-4up  PDF-4up  PDF

Lecture 30: Exploring Encodings PS-4up  PDF-4up  PDF

Lecture 31: Languages and Encodings PS-4up  PDF-4up  PDF

Lecture 32: Entropy PS-4up  PDF-4up  PDF

Lecture 33: Entropy II PS-4up  PDF-4up  PDF

The Midterm covers through here.

Week 3: Module 8:

Lecture 34: Fundamental Theorems PS-4up  PDF-4up  PDF

Lecture 35: Entropy of English PS-4up  PDF-4up  PDF

Lecture 36: Entropy Odds and Ends PS-4up  PDF-4up  PDF

Week 3: Module 9:

Lecture 37: Cryptography PS-4up  PDF-4up  PDF

Lecture 38: Cryptography II PS-4up  PDF-4up  PDF

Lecture 39: Properties of Ciphers PS-4up  PDF-4up  PDF

Week 3: Module 10:

Lecture 40: Substitution Ciphers PS-4up  PDF-4up  PDF

Lecture 41: Using Information PS-4up  PDF-4up  PDF

Lecture 42: A Perfect Cipher PS-4up  PDF-4up  PDF

Lecture 43: Transposition Ciphers PS-4up  PDF-4up  PDF

Lecture 44: Symmetric vs. Asymmetric Encryption PS-4up  PDF-4up  PDF

Lecture 45: Stream and Block Encryption PS-4up  PDF-4up  PDF

Week 3: Module 11:

Lecture 46: Advanced Encryption Standard PS-4up  PDF-4up  PDF

Lecture 47: Modes of Usage PS-4up  PDF-4up  PDF

Lecture 48: Public Key Encryption PS-4up  PDF-4up  PDF

Lecture 49: Public Key Encryption II PS-4up  PDF-4up  PDF

Lecture 50: Cryptographic Hash Functions PS-4up  PDF-4up  PDF

Lecture 51: Key Exchange PS-4up  PDF-4up  PDF

Lecture 52: Diffie-Hellman Key Exchange PS-4up  PDF-4up  PDF

Week 4: Module 12:

Lecture 53: Digital Signatures PS-4up  PDF-4up  PDF

Lecture 54: Certificates PS-4up  PDF-4up  PDF

Lecture 55: Certificates II PS-4up  PDF-4up  PDF

Week 4: Module 13:

Lecture 56: Cryptographic Protocols PS-4up  PDF-4up  PDF

Lecture 57: Cryptographic Protocols II PS-4up  PDF-4up  PDF

Lecture 58: Cryptographic Protocols Abstractly PS-4up  PDF-4up  PDF

Week 4: Module 14:

Lecture 59: Attacks on Cryptographic Protocols PS-4up  PDF-4up  PDF

Lecture 60: The Needham-Schroeder Protocol PS-4up  PDF-4up  PDF

Lecture 61: Attacks on Needham-Schroeder PS-4up  PDF-4up  PDF

Lecture 62: The Otway-Rees Protocol PS-4up  PDF-4up  PDF

Lecture 63: Protocol Verification PS-4up  PDF-4up  PDF

Lecture 64: The BAN Logic PS-4up  PDF-4up  PDF

Lecture 65: The BAN Logic: Needham-Schroeder PS-4up  PDF-4up  PDF

Week 5: Module 15:

Lecture 66: PGP PS-4up  PDF-4up  PDF

Lecture 67: PGP Services PS-4up  PDF-4up  PDF

Lecture 68: PGP Services II PS-4up  PDF-4up  PDF

Lecture 69: PGP Key Management PS-4up  PDF-4up  PDF

Lecture 70: PGP Key Management II PS-4up  PDF-4up  PDF

Week 5: Module 16:

Lecture 71: Availability PS-4up  PDF-4up  PDF

Lecture 72: Availability II PS-4up  PDF-4up  PDF

Lecture 73: Intrusion Detection PS-4up  PDF-4up  PDF

Lecture 74: Anatomy of an Attack: CodeRed PS-4up  PDF-4up  PDF

Lecture 75: CodeRedII PS-4up  PDF-4up  PDF

Week 5: Module 17:

Lecture 76: Certification PS-4up  PDF-4up  PDF

Lecture 77: The Common Criteria PS-4up  PDF-4up  PDF

Lecture 78: Protection Profile Example PS-4up  PDF-4up  PDF

Lecture 79: Security Target Example PS-4up  PDF-4up  PDF

Lecture 80: CC Evaluations PS-4up  PDF-4up  PDF

That's all, folks!


There will be 5-6 programming assigments over the course of the semester. They should be done in the Java programming language. If you don't know Java, discuss it with me and I may allow an alternative arrangement. Each student may work on programming assignments in collaboration with one other student. Make sure that all submissions clearly identify which students contributed to the project.

You have another standing assignment: For each video you view, there are several short essay questions to be answered. Collectively, these questions are counted as equal to two programming assignments. They are linked below. The questions are typically due at 5pm on the Thursday of the week they are assigned. You are strongly encouraged to attempt them before you come to class on Thursday so you can ask any questions you may have, and be prepared for a possible quiz.

Programs will be graded on a 10 point scale, and will be accepted up to two days late with a deduction of one point per day late, up to 2 days late. The summer term is too short to allow much grace on this, so make sure you keep up. The number of days late is purely a function of the timestamp recorded when you submit the assignment. The TAs may also allocate a number of "slip days" that you can use at your discretion over the course of the semester. The TAs may turn off the turnin program after the due date, and accept late assignments by email. Please coordinate with the TAs regarding late submissions, or if you desire to re-submit an assignment following the due date.

After an assignment has been graded, it is your responsibility to check Blackboard to see that your assignment grades have been posted correctly. It's not OK to complain at the end of the semester that some grades weren't posted or were posted incorrectly.

Instructions for turnin: Programs and question assignments will be submitted via the turnin program. For every assignment, please submit your homework using the turnin command on CS lab machines. You can read the instructions by typing "man turnin". For example, type "turnin --submit username_ta hw# <file1> <file2>" to submit file1,file2 to TA as homework. You can use "turnin --verify username_ta hw#" to check your submission.

We'll post the command for turnin with each assignment.

Links to all assignments will appear below. Check this page often and be sure to check that any particular assignment or due date has not been changed. Each week expect one set of questions on the lectures. Programming assignments will come about every week.

Questions Week 1: Week 1: Due Thursday, 6/12 by 5pm

Assignment 1: Due Friday, 6/13/14 by midnight

Questions Week 2: Week 2: Due Thursday, 6/19 by 5pm

Assignment 2: Due Friday, 6/20/14 by midnight

< Questions Week 3: Week 3: Due Thursday, 6/26 by 5pm

Assignment 3: Due Friday, 6/27/14 by midnight

Assignment 4: Due Thursday, 7/3/14 by midnight

Questions Week 4: Week 4: Due Thursday, 7/3/14 by 5pm

Questions Week 5: Week 5: Due Thursday, 7/10/14 by 5pm

Assignment 5: Due Thursday, 7/10/14 by midnight


Short in-class quizzes may be given at any time. These will cover material previously covered or material in the mini-lectures you were expected to view. Material for a week is fair game for a Thursday quiz. The goal of quizzes is to test your understanding of the material and to give you an idea of the types of questions that will appear on tests. There will be no makeups for quizzes you miss, but any single quiz is only a small proportion of your final grade.


There will be two major tests during the semester: a midterm and final. Tests are closed-book, closed-notes tests, except that you may bring a single handwritten 3 x 5 inch index card of notes (both sides) for the midterm, and two such cards for the final. Your best study strategy is to review the class notes and ensure that you understand thoroughly the topics we have covered. Sample tests and vocabulary lists will be posted.

Our final exam is Friday, July 11, from 7-10pm in ART 1.102. Here's the sample final: Sample Final, and tentative vocabulary list: Vocabulary. This sample is not very representative of the test you'll be given; your test has more short answer questions and very few "essay" type questions. The final will be cumulative. You can bring two index cards of material to the exam. The vocabulary sheet will be made available with the exam.

No laptops:

Students should not have laptops or other electronic devices open during class discussions. Copies of all slides are provided. Please just listen, participate and absorb the material.

Grading policies:

Class attendance is mandatory for our two weekly meetings, and will be checked. Excessive unexcused absences will result in a reduced grade. If you don't plan to come to class regularly, please don't register for this class. Signing in for another student not present will be considered cheating by both students.

Grades are averaged using the weighting below:

Component Percent
Attendance, Quizzes and Participation10%
Assignments 40%
Midterm Exam 25%
Final Exam 25%

Course grades are assigned on the scale: A = 90-100; B = 80-90; etc. (I don't grade on the +/- grading system.) However, I reserve the right to be more generous than these ranges indicate. That is, I may enlarge any of these ranges; I will not shrink any range.

Scholastic Dishonesty:

Academic dishonesty will not be tolerated. See http://www.cs.utexas.edu/academics/conduct for an excellent summary of expectations of a student in a CS class.

All work must be the student's own effort (with the exception of group effort on programs). Work by students in previous semesters is not your own effort. Don't even think about turning in such work as your own, or even using it as a basis for your work. We have very sophisticated tools to find such cheating and we use them routinely. Several students didn't heed this warning in past semesters and paid a heavy price. It's far better to get a 0 on an assignment than to cheat.

No deviation from the standards of scholastic honesty or professional integrity will be tolerated. Scholastic dishonesty is a serious violation of UT policy; and will likely result in an automatic F in the course and may result in further penalties imposed by the department or by the university. Don't do it. If you are caught, you will regret it. And if you're not caught, you're still a cheater.

Students with Disabilities:

Students with disabilities may request appropriate academic accommodations from the Division of Diversity and Community Engagement, Services for Students with Disabilities, 471-6259, http://www.utexas.edu/diversity/ddce/ssd.

Some Interesting Links:

As I find articles or websites that seem of interest to this class, I'll post them below. The most recent are at the top.

Short of Cyberwarriors
Hackers Wanted
Health Hack Inevitable
Top IT Job Salaries
CS Enrollments Soaring
Cyberwarriors Needed
Security: A Higher Calling?
Covert Channels in Acoustical Networks
Homomorphic Encryption
Government doesn't follow best practice.
Adobe Encrypts Passwords
Women needed in Cybersecurity
Morris Worm at 25
Women in CS
Rijndael animation
Scholars for Service program
$1M Cyber challenge
Cybersecurity jobs
NSA breaking encryptions
Blocking Malware
Security jobs hot
Attracting security pros
Hacking Airplanes
Human side of cybercrime
IT Jobs Up, Degrees Down
Is RSA Obsolete?
Preventing Cyber Pearl Harbor

Cyberjobs Hot
Covert Channel between VMs
Anti-Virus Failures
Info on AES mixColumns
Peter Neumann
Experts needed
Govt wants hackers
Women, minorities in Security
This site contains a nice animation of AES-128: AES
Cute cartoon about Feistel ciphers
Encryption for the masses
Fully Secure OS?
iPad as Secure Device
protecting passwords
DoD Money for Hackerspaces
Cities with Most CS Jobs
Have Hackers Won?
Malware Pre-installed
Smother Cyber Attacks
Sale of Zero-day exploits
Algorithms rule the world
Hotel locks hacked
Cyber attacks
Flaw in AES
Zodiac Message
One Time Pad
Cyber Camp
Hot Skills for 2011
Cyber attack threat