Highlights of the Cryptographic Toolbox (2)

Cryptography, as most people know, has the answers to life's most important questions. How can we share a secret with 100 people so that any 50 of them can learn the secret if they get together, but no group of 49 of them can do so? How can I prove to you that I can tell brie from camembert without you learning anything about how I do it? How can a modern society have money without a central bank? And of course, the classic: how can we send messages over the Internet without the people who control the network being able to read our messages or concoct fake ones?
The semilab will discuss: (1) ciphers and encryption, (2) secret sharing and multiparty computation, and (3) zero-knowledge proofs. Along the way we will learn some basic number theory, strategies for playing "Where's Waldo" with little kids, and other valuable life lessons.