Quantum-resistant hierarchical consensus protocol (QRHCP) for enhanced security in blockchain networks

Abstract

Blockchain networks face escalating security challenges, including quantum computing threats, Sybil attacks, and scalability bottlenecks. Existing consensus mechanisms like Proof-of-Work (PoW) and Proof-of-Stake (PoS) lack adaptive security features and quantum resistance. This paper introduces the Quantum-Resistant Hierarchical Consensus Protocol (QRHCP), a novel hybrid framework combining Hierarchical Byzantine Fault Tolerance (HBFT), lattice-based post-quantum signatures, dynamic sharding, and a deception-based Sybil resistance mechanism. QRHCP organizes nodes in a multi-layered validation hierarchy, where root validators finalize blocks while edge validators process lightweight transactions. To counter quantum threats, we integrate CRYSTALS-Dilithium signatures in a dual-signature scheme, ensuring backward compatibility while transitioning to quantum-safe cryptography. Additionally, Adaptive Dynamic Sharding (ADS) optimizes network performance by dynamically splitting or merging shards based on real-time threat analysis. We evaluate QRHCP against Byzantine attack resistance, quantum vulnerability, and transaction throughput using a custom blockchain simulator. Results show 40% faster consensus latency compared to PBFT, 99.9% Sybil attack detection via the Decoy Chain Mechanism (DCM), and scalability up to 10,000 TPS under adaptive sharding. Our work provides a provably secure, quantum-resistant, and highly scalable consensus model for next-generation blockchain applications.