An FPGA-Based Communication Scheme of Classical Channel in High-Speed QKD System

The development of quantum computer technology has brought unprecedented threats to traditional cryptography methods. So far, the combination of Quantum Key Distribution (QKD) and one-time pad cryptography is the best solution to overcome the problem since it makes provable information-theoretic secure encryption possible. While the final key generation rate of most QKD systems cannot meet the needs of practical applications. One of the important reasons is the unsatisfied performance of communication scheme of classical channel in the QKD post processing system (QKDPPS). In this paper, an efficient FPGA-based communication scheme of classical channel in high speed QKD system is presented. Considering the following features of high transmission speed, multiple data types, large data quantity and strict data sequence of the communication over classical channel in a high-speed QKD system, the optical fiber is chosen as the communication medium and a high performance transmission protocol suitable for QKD is designed, including the packeting strategy based on data exchange rate and a reliability assurance scheme on the data link layer. The experimental results demonstrate that our communication scheme can provide stable communication service at 1.66 Gbps for a high-speed QKD system.