Secure communication on the internet relies on asymmetric (public-private) key pairs to encrypt and/or sign digital messages. The security of public-private key algorithms is based on the belief that factoring large numbers is computationally difficult and practically impossible. On classical computers running state-of-the art algorithms this is true. However, a new class of so-called “quantum computers” currently under development by researchers around the world will be able to short-cut this factoring problem. In this talk I’ll give an overview of how quantum computers will be able to break RSA encryption (and hence existing internet security), and describe another way to securely transmit digital messages that, based on the fundamental laws of physics, is provably unbreakable. This talk will be light on math with plenty of analogies and entertaining thought experiments.