30 Oct 2014 - Petros Wallden

Quantum Cryptography II

Abstract

In the previous talk, I gave the first protocol that using quantum mechanics achieved to distribute a secret key with unconditional security (BB84). Quantum Mechanics allow for an even more impressive result, namely that one can distribute a secret key between two parties with unconditional security even if the device used was prepared from an adversary and given to them as a black box (the assumptions will become clear)! The Device Independent QKD relies on the fundamental non-locality that quantum mechanics have, which Einstein called "spooky action at a distance". This property has troubled philosophers but also appears to be the source of new possibilities in quantum cryptography and quantum computing. In this presentation I will give some background on quantum non-locality and present the QKD protocol of Ekert 1991 (the first using this property). I will assume no prior knowledge of quantum mechanics.