PhD Seminar • Cryptography, Security, and Privacy (CrySP) — Group Key Exchange: A History

Friday, October 4, 2019 3:00 pm - 3:00 pm EDT (GMT -04:00)

Nik Unger, PhD candidate
David R. Cheriton School of Computer Science

How can a group of devices securely communicate over an insecure network? If there are only two devices in the group, we have an amazing solution: the Diffie-Hellman key exchange. We even have a fancy cryptographic trick to solve the problem for a group of three devices.

But what if a group of four devices wants to securely communicate? What if there are even more than four devices? Perhaps surprisingly, we don't yet know of a good way to solve this problem. We are lacking suitable cryptography.

This talk will take you on a tour of the long history of trying to solve this problem with *unsuitable* cryptography. Along the way, we will encounter ideas that are surprisingly geometric in nature, and bring them to life with visualizations.

This talk assumes some basic familiarity with public-key cryptography and the Diffie-Hellman key exchange.