# Dual-phase-modulated plug-and-play measurement-device-independent continuous-variable quantum key distribution

## TL;DR

This paper introduces an improved plug-and-play measurement-device-independent continuous-variable quantum key distribution scheme using dual-phase modulation, enhancing security and efficiency without performance loss, and providing practical implementation guidance.

## Contribution

The paper presents a novel DPM-based MDI-CVQKD protocol that eliminates the synchronous loophole and improves secret key rates with finite-size effects considered.

## Key findings

- Eliminates the synchronous loophole in plug-and-play MDI-CVQKD.
- Increases secret key rate by fully exploiting raw keys.
- Provides an experimental concept for practical implementation.

## Abstract

We suggest an improved plug-and-play measurement-device-independent (MDI) continuous-variable quantum key distribution (CVQKD) via the dual-phase modulation (DPM), aiming to solve an implementation problem with no extra performance penalty. The synchronous loophole of different lasers from Alice and Bob can be elegantly eliminated in the plug-and-play configuration, which gives birth to the convenient implementation when comparing to the Gaussian-modulated coherent-state protocol. While the local oscillator (LO) can be locally generated by the trusted part Charlie, the LO-aimed attacks can be accurately detected in the data post-processing. We derive the security bounds of the DPM-based MDI-CVQKD against optimal Gaussian collective attacks. Taking the finite-size effect into account, the secret key rate can be increased due to the fact that almost all raw keys of the MDI-CVQKD system can be fully exploited for the final secret key generation without sacrificing raw keys in parameter estimation. Moreover, we give an experimental concept of the proposed scheme which can be deemed guideline for final implementation.