ISA656: Network Security

George Mason University, Computer Science, Spring 2018

Instructor: Prof. Foteini Baldimtsi (

Office Hours: Thursdays 2:00PM-4:00PM, Engineering 5333

Lectures: Thursdays 4:30PM-7:10PM, Location: Art and Design Building 2026

Course Summary

An in-depth introduction to the theory and practice of network security. It assumes basic knowledge of cryptography and its applications in modern network protocols. This course will train you how to "think like an adversary"---thinking about how adversary might attack a system by subverting and exploiting assumptions made during system design---and will discuss threat modeling and formal cryptographic approaches to defining and proving security or privacy.

The class provides deep coverage of widely used network security protocols such as SSL, TLS, SSH, Kerberos, IPSec, IKE, and PGP. It covers countermeasures to distributed denial of service attacks, security of routing protocols and the Domain Name System, e-mail security and spam countermeasures, wireless security, web security, trust negotiation and decentralized payment systems (Bitcoin like).

Prerequisites: ISA 562 and (ISA 612 or CS 555). There will be substantial programming involved in the assignments, and students should be familiar with setting up a Virtual Machine and programming in Python, C, Java or another language.

Required Materials

Text Book: Kaufman, Perlman, and Speciner. Network Security: Private Communication in a Public World, Second Edition, Prentice Hall PTR, 2002, ISBN 0130460192. (Required).

There will also be on-line news articles and research publications that will be required reading before some of the lectures.


Midterm: 30%

Assignments: 40% (4 assignments that will require both programming and problem solving)

Final Project: 25% (You will work on a project in network security with a writeup/presentation due at the end)

Class/Forum Participation: 5%

Assignments received the next day lose 20%, two days late 40% and after that no credit will be given. To be fair with everyone in class no exception will be made to the rule above.

Communications: We will use Blackboard to communicate with you. You are welcome to use the Discussion Board to set up study groups, to post interesting security incidents you read about (please tag these as "interesting incident in the news"), or to discuss the course with other students. If you have a question about the course you should: (a) Come to office hours, OR (b) Post to the Discussion Board. Please don't use private posts/emails to ask technical questions. The rest of the class is probably also interested in your question, so make it public!

Ethics: To defend a system you need to be able to think like an attacker, and that includes understanding techniques that can be used to compromise security. However, using those techniques in the real world may violate the law or the university's rules, and it may be unethical. Under some circumstances, even probing for weaknesses may result in severe penalties, up to and including expulsion, civil fines, and jail time. Our policy is that you must respect the privacy and property rights of others at all times, or else you will fail the course.

Acting lawfully and ethically is your responsibility. Carefully read the Computer Fraud and Abuse Act (CFAA), a federal statute that broadly criminalizes computer intrusion. This is one of several laws that govern "hacking". Understand what this law prohibits.

Honor code: All students must adhere to the GMU Honor Code. You can discuss lecture material with other students in class but you have to work on the assignments alone. More specifically: (1) You may not share actual code. In other words, the code you write must be entirely your own, which you must write and debug without looking at other people’s code. Do not permit others to copy your code. (2) You must write up your solutions completely on your own, without looking at other people’s write-ups. (3) You are welcome to use any textbooks, online sources, blogs, research papers, Wikipedia, etc in your assignment, as long as these are properly cited in any submitted work. Failure to do this is plagiarism and is serious violation of the GMU Honor Code and basic scientific ethics, and will not be tolerated.

Class Schedule (Tentative):



Introduction & Class logistics and

Cryptography Toolbox

Cryptography Toolbox II

Modes of Operation, MACs, Hash Functions, Padding

Public Crypto, PKIs, CAs

SSL/TLS, Kerberos

Cancelled (makeup on 04/19th 2pm)

Guest Lecture

Wireless Security

Kerberos, DNS, DNESSEC

IPSec, IKE, Firewalls

PGP, S/MIME, Email Spam, Review

Suggested Readings

Chapters 1.1-1.6 and 2.1-2.4

Security for encryption schemes: Ciphertext Only Attack (COA), Known Plaintext Attack (KPA), Chosen Plaintext Attack (CPA), Chosen Ciphertext Attack (CCA).

Chapters 3.1-3.3, 3.5, 3.6, 4.1-4.5

Misuse of RC4 in Microsoft Excel, RC4 attack on SSL/TLS, SSL Beast attack (reusing IV in CBC mode)

Chapters 4.1-4.5

Common pitfalls of CBC-MAC

Padding oracle attack (LuckyThirteen attack on TLS, POODLE attack on SSL)

Chapters 5.1, 5.2, 5.5, 5.7, 6.1, 6.4

Chapters 11.4, 13, 9.1, 15.1-15.5, 19

TLS 1.3 Specification, MIT kerberos

Slides on Blackboard

A DNSSEC tutorial, Kaminsky attach on DNS, DNSviz tool

Chapters 17,19,21,22

IPSec by Cisco, More on IPSec

Chapter 21,22,23


Princeton Bitcoin Book, Bitcoin Blockchain explorer

Student Presentations






Final Project

01/25 Lec. 1

02/01 Lec. 2

02/08 Lec. 3

02/15 Lec. 4

02/22 Lec. 5

03/01 Lec. 6

03/08 Lec. 7

03/22 Lec. 8

03/29 Lec. 9

04/05 Lec. 10


04/19 Lec 11

04/26 Lec 12

05/03 Lec 13


Bitcoin & Blockchain

Anonymity & Privacy

Final Project