The Security of SARG04 Protocol in Plug and Play Quantum Key Distribution system with an Untrusted Source

TL;DR

This paper analyzes the security of the SARG04 quantum key distribution protocol in plug-and-play systems with untrusted sources, proposing monitoring schemes to ensure security despite source control by eavesdroppers.

Contribution

It introduces active and passive source monitoring schemes to verify source parameters, addressing security concerns in untrusted source scenarios for SARG04.

Findings

Passive scheme effectively monitors sources in plug-and-play systems

Statistical fluctuation and noise are quantitatively analyzed

Passive scheme is practical for real-world implementation

Abstract

The SARG04 protocol is one of the most frequently used protocol in commercial plug-and-play quantum key distribution (QKD) system, where an eavesdropper can completely control or change the photon number statistics of the QKD source. To ensure the security of SARG04 protocol in plug-and-play QKD system with an unknown and untrusted source, the bounds of a few statistical parameters of the source need to be monitored. An active or a passive source monitor schemes are proposed to verify these parameters. Furthermore, the practical issues due to statistical fluctuation and detection noise in the source monitoring process are quantitatively analyzed. Our simulation results show that the passive scheme can be efficiently applied to plug-and-play system with SARG04 protocol.