Abstract: Quantum key distribution (QKD) is one of the most mature applications of quantum information science. It is a provably secure technique that allows two spatially remote users to share a secret key in the presence of a powerful eavesdropper. In this talk, I will introduce the first and most commonly implemented QKD protocol – Bennet and Brassard-84 (BB84). Specifically, I will discuss implementations of BB84 protocol using a photon’s polarization, as well as the time-phase degree of freedom. To demonstrate that the security of QKD protocols originate from fundamental properties of quantum mechanics, I will discuss a hacking strategy that an eavesdropper can implement, and show that the protocol remains robust against such strategies.
