Abstract

Quantum key distribution (QKD) is a technique to securely grow a shared secret key between two remote parties [1]. Commercial implementations of QKD are available since 2005 and are used to secure network traffic (Fig. 1). QKD is proven unconditionally secure based on the laws of quantum physics [2]. However, security proofs necessarily assume an idealized model of equipment. Numerous discrepancies between the model and actual hardware have been found, leading to loopholes that can be used to eavesdrop the secret key.

© 2011 IEEE