With the rise of quantum computing, it has become evident that our current encryption protocols to send secure communication are not adequate anymore. In this class, hosted by the Yale Quantum Institute for the Jackson School for Global Affairs, Professor Steve Girvin teaches how to send secure communication in a quantum world, using the BB84 protocol for a secure quantum key distribution. The students learned about the protocol and then participated to hands-on small group activities to share secret key securely between each other (from Alice to Bob), and detect possible eavesdroppers (Eve). This class was prepared with the help of Florian Carle (YQI Manager), Jahan Claes (YQI Fellow), Shraddha Singh (Graduate Student), and Kevin Smith (Postdoctoral Associate), and part of the Schmidt Program on Artificial Intelligence, Emerging Technologies, and National Power.