Continuous-variable quantum key distribution system: Past, present, and future

Abstract

Quantum key distribution provides secure keys with information-theoretic security ensured by the principle of quantum mechanics. The continuous-variable version of quantum key distribution using coherent states offers the advantages of its compatibility with telecom industry, e.g., using commercial laser and homodyne detector, is now going through a booming period. In this review article, we describe the principle of continuous-variable quantum key distribution system; focus on protocols based on coherent states, whose systems are gradually moving from proof-of-principle lab demonstrations to in-field implementations and technological prototypes. We start by reviewing the theoretical protocols and the current security status of these protocols. Then, we discuss the system structure, the key module, and the mainstream system implementations. The advanced progresses for future applications are discussed, including the digital techniques, system on chip, and point-to-multipoint system. Finally, we discuss the practical security of the system and conclude with promising perspectives in this research field.

Security analysis of unidimensional continuous-variable quantum key distribution with discretized amplitude modulation

“…Quantum key distribution (QKD) enables two distant legitimate parties, Alice and Bob, to share a secret key in an unsecure quantum channel controlled by an eavesdropper Eve [1,2]. Due to the unconditional security guaranteed by the nocloning theorem, as well as the high compatibility with stateof-the-art fiber optical communication systems, continuous variable QKD (CVQKD) has attracted much attention [3][4][5][6]. Over the past decade, considerable advancements have been achieved in the theoretical and experimental development of CVQKD protocols [7][8][9][10][11][12][13].…”

Quantum Key Distribution with Displaced Thermal States

“…Quantum communication has witnessed remarkable strides [ 3 , 4 ] in the last few years, starting with the launch of a quantum satellite in 2016 that has recently been used to transmit quantum keys over 1200 km [ 5 ]. This marked a significant step towards realizing global-scale quantum key distribution (QKD).…”