The authors present a comparison between the basic BB84 Quantum Key Distribution (QKD) and its optimised version based on Quantum Dense Coding, in terms of theoretical modelling and feasibility of circuits implementations. These circuits are mainly composed of probabilistic quantum gates, single photon sources, beam splitters (BSs), polarising BS and single photon detectors. They assume that the photonic devices composing the circuits are not perfect. They assess the average success probabilities of the two protocols depending on the success probability of the photonic sources used and the distance between Alice and Bob. They demonstrate that typical real-world photonic devices permit the implementation of secure communication with 0.65 of success probability over 120 km, while it could reach more than 0.9 over 148 km if just deterministic sources are provided. \© 2018 The Institution of Engineering and Technology.

}, keywords = {Particle beams, Photonic devices, Photonic sources, Photons, Physical feasibility, Probability, Quantum circuit, Quantum cryptography, Quantum dense coding, Quantum electronics, Single-photon detectors, Single-photon source, Success probabilities, Theoretical modelling, Timing circuits}, doi = {10.1049/iet-ifs.2017.0375}, author = {A. Gueddana and V. Lakshminarayanan} }