An Information-theoretical Secured Byzantine-fault Tolerance Consensus in Quantum Key Distribution Network

TL;DR

This paper introduces an information-theoretic secure Byzantine-fault tolerant consensus protocol for QKD networks, enabling secure end-to-end key distribution even with dishonest relays acting as Byzantine nodes.

Contribution

It proposes a novel ITS BFT consensus protocol tailored for QKD networks, addressing active and passive relay attacks with theoretical analysis and simulation validation.

Findings

The scheme achieves secure end-to-end key distribution in the presence of Byzantine nodes.

The proposed protocol maintains security against passive and active relay attacks.

Simulation results confirm the feasibility and performance of the scheme.

Abstract

Quantum key distribution (QKD) networks is expected to provide information-theoretical secured (ITS) communication over long distances. QKD networks based trusted relay architecture are now the most widely used scheme in practice. However, it is an unrealistic assumption that all relays are fully trustable in complex networks. In the past, only a few studies have theoretically analyzed the case of passive eavesdropping attack by dishonest relays and corresponding defense method. However, we have found that active attacks by dishonest relays can be more threatening. With the consideration of passive and active attacks, we treat dishonest relays as Byzantine nodes and analyzes the upper limit of Byzantine nodes that the QKD network can accommodate. In this paper, we propose an ITS Byzantine-fault tolerance (BFT) QKD network scheme to achieve end-to-end key distribution based on point-to-point QKD links. To ensure consistency and provide BFT ability in the QKD network, we design an ITSBFT-consensus protocol for this network scheme. To ensure the information-theoretic security of consensus, we design a temporary signature scheme based on point-to-point QKD link keys. To prevent Byzantine nodes from disrupting the execution process of key distribution, we design an end-to-end key distribution scheme combined with consensus. We theoretically analyze proposed ITSBFT-QKD network scheme from four aspects: QKD key distribution security, temporary signature security, consensus security, and leader election fairness. The simulation result proved the feasibility and demonstrate the performance.