CSE316 review

Note: I found the course material for 19/20 is copied from an online course so if you are interested and want to learn better, you should check it

Lecture 1

Some import definitions:

  • Security

  • Protection

  • Vulnerabilities

  • Exploits

  • Trust

Security Goals:

  • Confidentiality < ---related to--- > Interception Threat

  • Intergrity < ---related to--- > Modification Threat, Fabriction Threat

  • Avilability < ---related to--- > Interruption Threat

Threats:

  • Theft

  • Privacy

  • Destruction

  • Interruption or interference with computer-controlled services

Design principles for secure systems:

  • Economy

  • Complete mediation

  • Open design

    • Kerckhoff principle: A cryptographic system should be secure even if everything about the system, except the key, is public knowledge.

  • Separation of privileges

  • Least privilege

  • Least common mechanism

  • Acceptability

  • Fail-safe defaults

Tools for security:

  • Access control

  • Encryption

  • Authentication

  • Intrusion detection

  • Common sense

Lecture 2 Classical and Modern Cryptography

  1. Classical Cryptography:

  2. Private-key encryption

    • secure communication

    • secure storage

  3. The shift cipher

  4. Modular arithmetic

  5. The Vigenere cipher

Sufficient key space principle:

  • The key space should be large enough to prevent "brute-force" exhausticve-search attacks

  1. Modern Cryptography:

  2. Crypto definitions:

    • Threat Model

    • Security guarantee/goal

  3. Assumptions

  4. Proofs of security

  5. Perfect secrecy:

The goal for security encryption is "impossible for the attacker to learn the key" -> "Regardless of any prior information the attacker has about the plaintext, the ciphertext should leak no additional information about the plaintext"

  • Ciphertext-only attack

  • Known-plaintext attack

  • Chosen-plaintext attack

  • Chosen-ciphertext attack

  • Attacker’s information about the plaintext = attacker known distribution of the plaintext

  • Perfect secrecy means that observing the ciphertext should not change the attacker’s knowledge about the distribution of the plaintext.

  • One-time pad

  • Computational secrecy

Last updated