A Real-Time Design Based on FPGA for Expeditious Error Reconciliation in QKD System

For high-speed quantum key distribution systems, error reconciliation is often the bottleneck affecting system performance. By exchanging common information through a public channel, the identical key can be generated on both communicating sides. However, the necessity to eliminate disclosed bits for security reasons lowers the final key rate. To improve this key rate, the amount of disclosed bits should be minimized. In addition, decreasing the time spent on error reconciliation also improves the key rate. In this paper, we introduce a practical method for expeditious error reconciliation implemented in a field programmable gate array for a discrete variable quantum key distribution system, and illustrate the superiority of this method to other similar algorithms running on a PC. Experimental results demonstrate the rapidity of the proposed protocol.