Course - Computer Security MT24

A Part A/Part B course on computer security, with a heavy focus on information security.

A lot of the information security topics rely on some foundational assumptions in computational complexity, most strongly that one-way functions exist – i.e. there exist functions $f$ where $f(x)$ is easy to compute but $f^{-1}(x)$ is very difficult to compute. Whether one-way functions exist is actually still an open problem! The existence of one-way functions would imply $\mathbf P = \mathbf{NP}$, so a proof of this fact is expected to be very difficult. Some of [[Course - Quantum Information HT24]]^U instead builds up protocols of secure communication founded in quantum theory, whose security is founded in laws of nature rather than hard computational problems.

• Course Webpage
• Lecture Notes
  • Andrew Ker’s lecture notes (from 2014, and don’t cover all content)
  • 1, Introduction
  • 2, Access control
  • 3, Attacks
  • From the previous year:
    • Andrew Ker’s lecture notes
    • 1, Introduction
    • 2, Access control
    • 3, Attacks
    • 4, Symmetric-key cryptography
    • 5, Hashes
    • 6, Asymmetric crypto
    • 7, MAC
    • 8, Protocols
    • 9, Frameworks
    • 10, NSA slides
• Other courses this term: [[Courses MT24]]^U

Timetable

• Monday 11AM-12PM, Weeks 1,2,3,4,5,7 (lecture)
• Wednesday 11AM-12PM, Weeks 1,2,3,4,5,7 (lecture)
• Friday 11AM-12PM, Weeks 1-4 (lecture)
• Monday 10AM-11AM, Weekly 4,5,7,8 (class)

Notes

• [[Notes - Computer Security MT24, Basic definitions]]^U
• [[Notes - Computer Security MT24, Access control]]^U
• [[Notes - Computer Security MT24, Bell-LaPadula model]]^U
• [[Notes - Computer Security MT24, Clark-Wilson model]]^?
• [[Notes - Computer Security MT24, Access control in UNIX]]^?
• [[Notes - Computer Security MT24, Reference monitors]]^U
• [[Notes - Computer Security MT24, Attacks]]^U
• [[Notes - Computer Security MT24, Symmetric key ciphers]]^U
• [[Notes - Computer Security MT24, Cipher attacks]]^U
• [[Notes - Computer Security MT24, Feistel structures]]^U
• [[Notes - Computer Security MT24, DES cryptosystem]]^U
• [[Notes - Computer Security MT24, Cryptographic hashes]]^U
• [[Notes - Computer Security MT24, Key generation]]^U
• [[Notes - Computer Security MT24, Asymmetric key ciphers]]^U
• [[Notes - Computer Security MT24, Number theory]]^U
• [[Notes - Computer Security MT24, RSA cryptosystem]]^U
• [[Notes - Computer Security MT24, Rabin cryptosystem]]^U
• [[Notes - Computer Security MT24, Diffie-Hellman key exchange]]^U
• [[Notes - Computer Security MT24, Dolev-Yao model]]^U
• [[Notes - Computer Security MT24, MACs]]^U
• [[Notes - Computer Security MT24, Digital signatures]]^U
• [[Notes - Computer Security MT24, Protocols]]^U
• [[Notes - Computer Security MT24, Needham-Schroeder protocol]]^U
• [[Notes - Computer Security MT24, Key distribution and mediated authentication]]^U
• [[Notes - Computer Security MT24, SSL and TLS]]^U

Problem Sheets

• [[Problem Sheet - Computer Security MT24, I]]^?, Sheet 1
• [[Problem Sheet - Computer Security MT24, II]]^?
• [[Problem Sheet - Computer Security MT24, III]]^?
• [[Problem Sheet - Computer Security MT24, IV]]^?
• From the previous year:
  • Sheet 1
  • Sheet 2
  • Sheet 3
  • Sheet 4

To-do List

• Go over all topics covered in slides but not covered in lectures
• Address todo items in notes above
• Example of a buffer overflow attack
• Details of RC4 stream cipher?
  • Explanation in slides is better
• Go back over message integrity 4.5 if not covered later in the notes
• Why does MD-compliant padding prevent “these attacks” (and what does “these” refer to?)
• Details for specific hashing algorithms like MD4?
• Better definition of cryptanalysis given in the slides
• Diagrams for Fiestel structures/other ciphers
• Luby-Rackoff theorem
• Slides give better explanation of block ciphers vs. stream ciphers
• Slides also have a list of more weaknesses for each block mode, and illustrations are useful
  • Should refactor block modes into a separate entry
• Pseudocode for what exhaustion attacks look like on hash properties
• Details for time complexity of RSA operations
• Why the specific choices made in PKCS#1 v1.5
• Go over the slides for the lectures I missed (OAEP for RSA?)
• Details on elliptic-curve cryptography in the slides
• Why do RSA signatures work?
• Padding for RSA signatures, PKCS and RSA-PSS
• Retransmission attack for confidentiality with authentication
• Why is it preferable that the initiator should be first to prove their identity (page 114)
• More details on certificates in the slides
• Attacks on TLS?
• Lecturer said that there is always a big focus on protocols in the exam