Continuous-Variable Quantum Key Distribution: current status and prospects

Philippe Grangier

Takuya Hirano

In this talk, we will review the present status of continuous-variable quantum key distribution, including optical configuration and security analysis, and would like to discuss future prospects for integration with coherent optical communications.

Yongmin Li, Xuyang Wang, Zengliang Bai +3 more

Quantum key distribution enables unconditionally secure key distribution between two legitimate users. The information-theoretic security is guaranteed by the fundamental laws of quantum physics. Initially, the quantum key distribution protocol was proposed based on the qubits. Later on, it was found that quantum continuous variables can also be exploited for this target. The continuous variable quantum key distribution can build upon standard telecommunication technology and exhibits a higher secret key rate per pulse at a relatively short distance due to the possibility of encoding more than 1 bit per pulse. In this article, we review the current status of the continuous variable quantum key distribution research, including its basic principle, experimental implementations, security and future directions; the experimental progress in this field made by our group is also presented.

Cosmo Lupo

Evgenii V. Burlakov, Alexander V. Korobov

The key features of continuous variables quantum key distribution protocols are considered in the paper. The motivation for studying and developing methods of quantum cryptography is substantiated. The main aspects inherent to continuous-variable protocols are highlighted, and they are classified based on various characteristics, peculiarities, and implementation variants. A detailed examination of a protocol example with discrete modulation and signal registration through balanced homodyne detection is provided. A classification of attacks on the quantum protocol is presented. A general overview of post-processing methods is given. The role of noise is indicated, and approaches to assessing the level of security applicable to continuous-variable protocols are discussed. In conclusion, the main conclusions regarding the current status of this problem are presented, and aspects requiring further study are identified.

Romain Alléaume