Accelerated information reconciliation with elastic reconfiguration and check node-driven termination in fiber physical-layer security

In this study, we aim to further advance solutions to critical challenges in physical layer secure key generation and distribution (PLSKGD) for optical fiber communication, particularly the limitations of traditional information reconciliation (IR) protocols in mitigating initial key inconsistencies caused by noise and interference. We introduce two innovative approaches: a check node correlation coefficient-based early termination (CNCC-ET) scheme and an elastic reconfigurable (ER) scheme to enhance error correction performance and accelerate IR. The CNCC-ET scheme dynamically monitors the correlation coefficient of messages between check and variable nodes, enabling early termination of iterations when decoding is likely to fail, thus significantly reducing decoding complexity. In high bit error rate (BER) regions, this scheme achieves up to a 51.8% reduction in average iteration counts while maintaining low frame error rates (FER). Concurrently, our ER scheme adapts to varying BER conditions by dynamically adjusting the ratio of information to check bits, achieving a remarkable 90.26% FER reduction in high-BER scenarios. Hardware implementation on a Xilinx Virtex-7 FPGA validates the feasibility of these methods, demonstrating a 47.2% reduction in IR time overhead and significantly improved error correction capability. This study advances the development of more secure and efficient optical fiber communication systems, with potential applications extending to other physical layer security contexts.