Active basis choice for quantum key distribution with entangled states

Entangled quantum key distribution (QKD) is a promising way to generate pairs of unconditionally secret keys. In this paper we review possible realizations of entanglement-based QKD and assess their feasibility in terms of implementation complexity and provided security. We also propose a novel active basis choice approach that enables to use only one single-photon detector per user. The paper provides all necessary details including the required electro-optic crystal configurations to implement such a scheme experimentally.