LEARNING OUTCOMES

Upon completion of the course, students will be able to: explain the concepts of confidentiality, availability, and integrity (CIA) as well as the concepts of threat, vulnerability, exploit and (cyber-)risk and (cyber-)risk mitigation; explain the strengths and weaknesses of cryptographic techniques as well as their role in protecting data at rest and in transit, in implementing the concept of digital signature and in supporting the design of security protocols; explain the security model of web browsers and identify the most relevant vulnerabilities of web applications; explain the causes and effects of buffer overflows in executable programs; explain the key principles of access control in information systems and most relevant access control models and mechanisms.

AIMS AND LEARNING OUTCOMES

Students will acquire in-depth understanding of the security issues that plague modern Computer Systems and complex ICT infrastructures as well as of the techniques used to solve or, at least, mitigate them. Students will learn how to evaluate if the confidentiality, integrity and availability of data and communications is at risk and to identify appropriate solutions to achieve these fundamental security properties. The course features a series of hands-on sessions that provide students with the ability to solve practical problems drawn from a variety of domains: cryptography, network security, host security and web security.

PREREQUISITES

• Good programming skills
• Fundamentals of Computer Architectures and Operating Systems
• Fundamentals of communication protocols and the TCP/IP

TEACHING METHODS

Lecture-style instruction complemented with hands-on session on selected topics (e.g. secure mail, web security).

The examination consists of a written and a practical exam (cyber exercise).

SYLLABUS/CONTENT

1. Introduction Computer Security [1h]

   • The concepts of resource, vulnerability, threat, countermeasure, and risk

   • Security goals: confidentiality, integrity, availability, ...

2. Introduction to Cryptography [2h]

   • Fundamental concepts (cryptography, cryptanalysis, general cryptographic schema)

   • Monoalphabetic substitution ciphers (Caesar cipher)

   • Polyalphabetic substitution ciphers (Vigenère cipher)

   • One-time pads (Vernam cipher)

   • Transposition ciphers

   • Composite ciphers

3. Symmetric Cryptography [3h]

   • Block and stream ciphers

   • Feistel cipher structure

   • DES and 3DES

   • Modes of operation (Electronic Code Book, Cipher-Block Chaining, Stream Ciphers)

   • Link vs end-to-end encryption

   • The key distribution problem

4. Public-Key Cryptography [6h]

   • Introduction to public-key cryptography

   • Introduction to Number Theory

   • The RSA algorithm

   • Diffie-Hellman key exchange

5. Message Authentication and Digital Signatures [3h]

   • Message integrity and authentication functions (message encryption, message authentication code, cryptographic hash functions)

   • Digital signature

6. Public Key Infrastructure (PKI) [3h]

   • PKI components

   • Digital Certificates

   • Trust models

7. Security Protocols [6h]

   • Basic notions (protocol execution, assumptions and goals, attacker model)

   • Examples of protocols (NSPK, Otway-Rees, Andrew Secure RPC, Denning & Sacco)

   • Prudent engineering of security protocols

   • Kerberos (architecture, protocol, inter-realm communication, limitations)

8. Secure mail [3h+3h hands on]

   • PGP

9. Network Security [6h]

   • Link Layer: WiFi Security

   • Network Layer: IP-Sec

   • Transport Layer: SSL/TLS

   • Introduction to Firewalls

10. Web Security [6h + 6h hands on]

    • Security on the client side (cookies and privacy, HTTP authentication mechanisms)

    • Security on the server side (unvalidated input, broken authentication and session management, cross-site scripting, injection flaws, denial of service, ...)

11. Secure Programming [6h]

    • Buffer overflows

    • Format string vulnerabilities

12. Access Control [6h]

    • Discretionary vs Mandatory Access Control

    • Access control matrix model

    • Role-Based Access Control (RBAC)

    • Administrative Role-Based Access Control (ARBAC)

    • I modelli di Bell-LaPadula, Harrison-Ruzzo-Ullman, Chinese Wall

13. Cyber Exercise [12h hands on]

RECOMMENDED READING/BIBLIOGRAPHY

Teaching material (slides and exercises) are available on AulaWeb.

Charles P. Pfleeger Shari Lawrence Pfleeger. Security in Computing, 4/E. ISBN-10:0132390779, ISBN-13: 9780132390774, Prentice Hall Editor, 2007. (Available also in Italian)

William Stallings, Lawrie Brown. Computer Security: Principles and Practice (3rd Edition). Pearson Ed., 2015