Efficient quantum key distribution protocol based on classical–quantum polarized channels

To improve the efficiency of QKD systems, a new QKD protocol based on classical–quantum polarized channels is proposed in this article. By precoding the raw key with polar codes before communication, this protocol has higher code rate and lower time cost compared with the traditional ones. According to the attack strategies that eavesdroppers might employ, we have analyzed the protocol’s security under ideal and practical channel models. We prove that under proper channel parameter setting, the security of this protocol is not lower than BB84 under intercept strategy.