Enhancing QKD via Multi-Photon-Lane Systems With a Card-Shuffling-Based Approach

This paper introduces a modified quantum key distribution (QKD) protocol based on card-shuffling, designed to enhance security against eavesdropper photon number splitting (PNS) strategies. The proposed technique accommodates light pulses with few photons, substantially augmenting the effectiveness and reliability of QKD. It can be implemented as multi-photon-lane systems, enabling concurrent key distribution to multiple users or amalgamation of key data to amplify individual use r key rates. The study assesses the proposed technique utilizing three well-established polarization-encrypted QKD protocols, BB84, B92, and SSP99, and simulations utilizing 4-photon lane systems with wavelengths of 800 nm, 1300 nm, and 1550 nm. The findings, encompassing correlations such as useful key rate, maximum key distribution distance, quantum bit error rate, and photon number probability, are analyzed and compared under different conditions. The outcomes reveal that combining the technique with BB84-based systems employing 1300 nm light pulses and a photon number probability of 1.0 attains a maximum QKD effectiveness of 12.34 Gbit-km/s. Moreover, the effectiveness can be increased to 49.36 Gbit-km/s by implementing the proposed 4-photon-lane system as the serial key-combining scheme. The potential of using multi-photon-lane implementations alongside the proposed technique to enhance the effectiveness and reliability of QKD is theoretically investigated and discussed.