A reconciliation protocol with delayed error correction for quantum key distribution

Abstract

A delayed error-correction (EC) reconciliation protocol for quantum key distribution (QKD) is proposed in the paper, where the error correction operation is operated after the messages have been transmitted. There are two advantages of the proposed protocol. First, it is possible for the two nodes without a direct quantum link to share secret keys, when the two nodes are separately connected to a common trusted relay in the QKD network. Besides, the reconciliation protocol with the delayed EC also simplifies the whole reconciliation process. It corrects both errors caused by communications during QKD process and that inherent in message bits. The key generation rate of the delayed EC protocol is presented. Finally, the bit error rate of the proposed protocol is analyzed when using polar codes as the error correction codes. The results show that the performance of the delayed EC reconciliation protocol with polar codes were better than those using low-density parity check code.