QDBFT: A Dynamic Consensus Algorithm for Quantum-Secured Blockchain

TL;DR

QDBFT introduces a quantum-secured, dynamic consensus algorithm for blockchain that uses quantum key distribution and a hash ring for node rotation, enhancing security against quantum threats while maintaining efficiency.

Contribution

It presents a novel quantum-secured consensus protocol with dynamic node management and quantum key distribution integration, improving security and adaptability over existing methods.

Findings

Achieves comparable performance to PBFT in experiments.

Provides information-theoretic security against quantum attacks.

Supports dynamic node reconfiguration with equitable authority distribution.

Abstract

The security foundation of blockchain system relies primarily on classical cryptographic methods and consensus algorithms. However, the advent of quantum computing poses a significant threat to conventional public-key cryptosystems based on computational hardness assumptions. In particular, Shor's algorithm can efficiently solve discrete logarithm and integer factorization problems in polynomial time, thereby undermining the immutability and security guarantees of existing systems. Moreover, current Practical Byzantine Fault Tolerance (PBFT) protocols, widely adopted in consortium blockchains, suffer from high communication overhead and limited efficiency when coping with dynamic node reconfigurations, while offering no intrinsic protection against quantum adversaries. To address these challenges, we propose QDBFT, a quantum-secured dynamic consensus algorithm, with two main contributions: first,we design a primary node automatic rotation mechanism based on a consistent hash ring to enable consensus under dynamic membership changes, ensuring equitable authority distribution; second, we integrate Quantum Key Distribution (QKD) networks to provide message authentication for inter-node communication, thereby achieving information-theoretic security in the consensus process. Experimental evaluations demonstrate that QDBFT achieves performance comparable to traditional PBFT while delivering strong resilience against quantum attacks, making it a promising solution for future quantum-secure decentralized infrastructures.