АНАЛИЗ БЕЗОПАСНОСТИ РАСПРЕДЕЛЕНИЯ КВАНТОВЫХ КЛЮЧЕЙ В ПАССИВНЫХ ОПТИЧЕСКИХ СЕТЯХ

Abstract

The need for security for end users has led to the installation of Quantum Key Distribution (QKD) in one-to-many access networks such as passive optical networks. In networks, the presence of optical power splitters makes the secure key rate issues more important. However, research on QKD in access networks has mostly focused on implementation issues rather than developing a protocol to increase the key rate. Since the safe key rate is theoretically limited by the protocol, studies without protocol development cannot overcome the safe key rate limit given by the protocol. This necessitates research to develop a protocol. This article proposes a new approach that provides a secure increase in key transfer rate over the conventional protocol. A secure key rate formula in a passive optical network is proposed by extending the secure key rate formula based on the BB84 protocol with a honeypot state. For a passive optical network, a method is proposed that includes collaboration between end users. We then show that this method can mitigate the photon number division (PNS) attack, which is critical in the well-known BB84 trap protocol. In particular, the proposed scheme allows multiphoton states to serve as secure keys, unlike the conventional BB84 decoy protocol. Numerical simulations show that our proposed scheme outperforms the BB84 honeypot protocol in terms of secure key speed.