COS 433 - Cryptography

Cryptography is an ancient practice dating back almost 4000 years. However, cryptography practiced today is very different than the cryptography used as recently as a few decades ago. For one, traditional cryptography was mostly synonymous with encryption: translating data into secret codes. Today, however, cryptography extends far beyond basic codes to encompass concepts such as authentication and integrity, and can be used to solve seemingly impossible tasks such as public key encryption (exchanging secret messages without ever having met in person to share a secret key) and zero knowledge proofs (proving theorems without revealing the proof).

Another new feature in modern cryptography is its foundations. Until recently, cryptography was largely an art form based on intuition and ad hoc tweaks to block vulnerabilities. Modern crytpography is instead more of a science, characterized by rigorous mathematical definitions and theorems that guide the design of new systems.

This course is an introduction to modern cryptography, focusing on the theoretical foundations, with some attention to practical considerations. We will cover a variety of topics, including secret key and public key encryption, authentication, commitments, pseudorandom generators, and zero knowledge proofs.

Basic probability theory. Basic complexity theory (as in COS340) recommended. The course projects will involve programming, but no specific programming language is required.