Suppose Alice and Bob are spies collaborating on the same project. But they live in different cities and have never met. Worse, their enemy Eve has access to all the messages they send to each other. Is it possible for Alice and Bob to talk with each other and still manage to keep their conversation top-secret? Miraculously, the answer is yes! In 1976, Diffie and Hellman came up with an ingenious way to do precisely this, and created the field of "public-key" cryptography, which is essential to almost every communication that takes place on the internet. In this class, we'll learn about their beautiful protocol, a foundational encryption algorithm and the first public-key encryption system to be published.

How can we multiply two numbers quickly? How do we sort a list quickly? What does "quickly" even mean? We'll explore these questions and many more in our study of algorithms, a beautiful field that lies at the heart of computer science.