Practical continuous-variable quantum secret sharing using local local oscillator

TL;DR

This paper introduces a practical continuous-variable quantum secret sharing scheme using local local oscillators, enhancing security against LO-aimed attacks and enabling large-scale quantum networks with high user capacity and transmission distance.

Contribution

The paper proposes a novel LLO-based CVQSS scheme that eliminates the need for transmitting LOs through untrusted channels, significantly improving security and scalability.

Findings

Supports 30 users simultaneously

Achieves a maximum transmission distance of 112 km

Provides security against LO-aimed attacks

Abstract

Although continuous-variable quantum secret sharing (CVQSS) has been theoretically proven to be secure, it may still be vulnerable to various local oscillator (LO)-aimed attacks. To close this loophole, we propose a practical CVQSS scheme using local LO (LLO), which is called LLO-CVQSS. In this scheme, LO is no longer generated by each user but can be locally generated by the legitimate party, i.e., the dealer. This waives the necessity that all LOs have to be transmitted through an untrusted channel, which makes CVQSS system naturally immune to all LO-aimed attacks, greatly enhancing its practical security. We also develop a specially designed phase compensation method for LLO-CVQSS so that the phase noise of the whole system can be eliminated. We finally construct a noise model for LLO-CVQSS and derive its security bound against both eavesdroppers and dishonest users. Numerical simulation shows that LLO-CVQSS is able to support 30 users at the same time and its maximal transmission distance reaches 112 km, revealing that LLO-CVQSS is not only has the ability to defend itself against all LO-aimed attacks but also has the potential for building large-scale practical quantum communication networks.