Mixed basis quantum key distribution with linear optics

TL;DR

This paper introduces a new two-qubit quantum key distribution protocol using a mixed basis, which improves efficiency, loss tolerance, and security against certain attacks, and can be implemented with current technology.

Contribution

It proposes a novel mixed basis QKD protocol based on linear optics that allows deterministic state discrimination and enhanced security features.

Findings

Deterministic discrimination of all states with linear optics.

Enhanced resistance to certain attacks compared to BB84.

Feasible implementation with current technology.

Abstract

Two-qubit quantum codes have been suggested to obtain better efficiency and higher loss tolerance in quantum key distribution. Here, we propose a two-qubit quantum key distribution protocol based on a mixed basis consisting of two Bell states and two states from the computational basis. All states can be generated from a single entangled photon pair resource by using local operations on only one auxiliary photon. Compared to other schemes it is also possible to deterministically discriminate all states using linear optics. Additionally, our protocol can be implemented with today's technology. When discussing the security of our protocol we find a much improved resistance against certain attacks as compared to the standard BB84 protocol.