Abstract

The aim of device independent quantum key distribution is to establish secret key using quantum devices that are untrusted, with security nonetheless guaranteed by the laws of physics. This is achieved by protocols that exploit nonlocal correlations produced by measurements performed on entangled quantum states. Somewhat remarkably, the security proofs hold even in the extreme case that quantum devices have been manufactured and supplied by the eavesdropper herself. Most protocols for DVIQKD , however, are highly inefficient in that they require separate devices to be used for each entangled pair of quantum systems. I will report on recent work by myself, Roger Colbeck and Adrian Kent that removes this requirement, leading to the possibility of efficient device independent protocols. If time I’ll also discuss the question of how to define composability of device independent protocols and describe some previously unnoticed problems.