Continuous-Variable Quantum Key Distribution: Background and Perspectives

The review examines the essential characteristics of continuous-variable quantum key distribution protocols. In these protocols, information is encoded into the complex amplitude of the optical field, which can have a continuous range of values, unlike a qubit. An advantage over many other quantum key distribution protocols is provided by the fact that the practical implementation of these protocols does not require sources and single-photon detectors. Additionally, they offer a relatively high rate of secret key generation. However, continuous-variable protocols require a specific analysis of secrecy and special consideration for the influence of noise that may arise during practical implementation. This presents a broad area for further research.