Security-enhanced Blockchain with Twin-Field Quantum Key Distribution: A Physical Layer enabled Architecture

TL;DR

This paper proposes a scalable, secure blockchain architecture integrating twin-field quantum key distribution and a hybrid quantum-classical design to enhance physical layer security and overcome distance limitations.

Contribution

It introduces a decoupled, linearly scalable architecture using MDI-TF QKD and dual-key stratification for improved security and scalability in quantum-secured blockchains.

Findings

Achieves linear scalability in quantum blockchain infrastructure.

Transforms symmetric security into publicly auditable evidence.

Overcomes rate-loss limits of classical security methods.

Abstract

Quantum computing provides a feasible multi-layered security challenge to classical blockchain networks. Quantum blockchains that rely on quantum key distribution (QKD) to establish secure channels can address this feasible threat. Whereas, there are still architecture limitations to practical security resulted in the measurement devices while implementing the QKD-secured blockchains in physical layer. This paper presents a quantum-classical hybrid architecture in a distributed blockchain to address the connectivity and distance limitations of the blockchain-embedded quantum networks. A decoupled architecture is designed felicitously so that it pairs a linearly scalable measurement-device-independent (MDI) physical layer with a decentralized consensus. It can optimize the complexity of infrastructure from quadratic to linear scaling, ascribed to leveraging the twin-field (TF) QKD protocol with the MDI-structurized star topology. Additionally, the dual-key stratification strategy transforms symmetric information-theoretic security into publicly auditable forward-secret blockchain evidence. This architecture can integrate the exact information-theoretic security (ITS) with distributed consensus mechanisms, allowing the scalable system to overcome the potential rate-loss limits inherent in classical security-weakened blockchains.