Finite-key analysis for a practical decoy-state twin-field quantum key distribution

Abstract

Twin-field quantum key distribution (TF-QKD), which is immune to all possible detector side channel attacks, enables two remote legitimate users to perform secure communications without quantum repeaters. With the help of a central node, TF-QKD is expected to overcome the linear key-rate constraint using current technologies. However, the security of the former TF-QKD protocols relies on the hypothesis of infinite-key and stable sources. In this paper, we present the finite-key analysis of a practical decoy-state twin-field quantum key distribution with variant statistical fluctuation models. We examine the composable security of the protocol with intensity fluctuations of unstable sources employing Azuma's inequality. Our simulation results indicate that the secret key rate is able to surpass the linear key-rate bound with limited signal pulses and intensity fluctuations. In addition, the effect of intensity fluctuations is extremely significant for small size of total signals.

We submitted this manuscript on July 19, 2019

References in corpus (6)

• Secure Quantum Key Distribution
• Quantum cryptography with finite resources: unconditional security bound for discrete-variable protocols with one-way post-processing
• Experimental quantum key distribution beyond the repeaterless secret key capacity
• Improved key rate bounds for practical decoy-state quantum key distribution systems
• Secure and efficient decoy-state quantum key distribution with inexact pulse intensities
• Asymmetric sending or not-sending twin-field quantum key distribution in practice