Efficient FPGA Implementation of Polar Codes-Based Information Reconciliation for Quantum Key Distribution

Quantum key distribution (QKD) leverages the principles of quantum mechanics to enable the generation of unconditionally secure keys for remote communication, even in the presence of an eavesdropper with unlimited computational power. A critical component of QKD is information reconciliation (IR), which mitigates bit errors introduced by system imperfections and channel noise, ensuring the integrity of the shared key. Polar codes-based IR schemes have attracted considerable attention due to their near-Shannon-limit performance and low computational complexity. However, existing implementations primarily rely on CPUs or GPUs, which are suboptimal in terms of performance and energy efficiency. Here, we present a hardware accelerator designed specifically for discrete variable QKD (DV-QKD), targeting polar codes-based IR and implemented on a cost-effective FPGA platform. Our design achieves high throughput and scalability by employing a module-level pipeline parallel structure, a fully parallelized decoding strategy, and a hybrid memory architecture. This approach maximizes decoder efficiency and optimizes resource utilization. On this platform, we demonstrate an IR throughput of 35.33 Mbps for a block size of 2 ²⁰ , providing a real-time, cost-efficient solution that significantly enhances the performance of QKD systems.