Cryptography and Security

Winter 2020 at ENS Lyon

General information

Lectures
- Omar Fawzi
- Wednesdays 10:15 to 12:15
- Amphi B
Tutorials
- Mateusz Skomra
- Thursdays 15:45 to 17:45

This course is an introduction to modern cryptography.

References

[BS] A Graduate Course on Applied Cryptography
[KL] Introduction to Modern Cryptography
[Gal] Mathematics of Public Key Cryptography for the mathematics behind the hard problems we will use in part of the course

For some online resources on probability (for computer science), you can look at these notes.

Grading

The grading scheme will take into account

A final exam
One midterm exam
Two homeworks

Schedule

Date	Topic	References
Jan 15th	Introduction. Perfect security. One-time pad. Shannon's theorem: Secret key must be long. Relaxing perfect secrecy: stream ciphers and pseudo-random generators.	Ch 2 and 3 of [BS], Ch 1 and 2 of [KL]
Jan 22nd	Pseudo-random generetors. Security of a PRG. Unpredictability of a PRG. Equivalence between security and unpredictability. Semantic security for ciphers (for one-time key and chosen plaintext)	Ch 2 and 3 of [BS], Ch 3 of [KL]
Jan 29th	Semantic security for stream ciphers. Pseudo-random functions, construction from PRG. Block ciphers (or PRPs). Brief overview of DES and AES. Encryption with block cipher (deterministic counter mode).	Ch 4 of [BS]
Feb 5th	CPA security. Randomized countermode is CPA secure. Message authentication codes.	Ch 5 and 6 of [BS]
Feb 12th	Message authentication codes from PRF. Signing longer messages with CBC-MAC. Authenticated encryption.	Ch 6 and 9 of [BS]

Homeworks