One of the classes that is just starting up at Udacity is on cryptography - you know, encryption and secret computer codes. While at Sun Labs I had the pleasure of working with Whit Diffie, co-inventor of the Diffie-Hellman algorithm that makes public key cryptography possible. What in the heck is that? you say. It is a mechanism that allows two parties to share secrets across a public communication channel. The video above tries to explain this process in simple terms and, for the most part, does a reasonable job.