Quantum-adaptive cryptography and adaptive multi-consensus layer for future-proof blockchain security and scalability

This is the authors' abstract. We don't add key points for this paper.

Quantum computing is an emerging technology that could easily break cryptographic algorithms and threaten transaction integrity in blockchain networks. Existing blockchain consensus mechanisms remain static, and they are not capable of adapting to dynamic security requirements, performance, and energy consumption. To address these limitations, this study proposes a Quantum-Adaptive Cryptography and Adaptive Multi-Consensus blockchain framework that dynamically responds to evolving quantum threats and network conditions. The framework employs an AI-driven decision tree model to classify quantum threat levels using features derived from the QM9 quantum chemical dataset. The decision tree classifier classifies quantum threat levels into either low, high, or moderate, which then triggers one of the cryptographic schemes of Elliptic Curve Digital Signature Algorithm (ECDSA), Crystal-Dilithium 3, or Hybrid ECDSA with Crystal-Dilithium, respectively. In parallel, a Bayesian optimization-based multi-consensus layer dynamically selects the most suitable consensus protocol (Proof of Stake (PoS), Practical Byzantine Fault Tolerance (PBFT), or democratic Byzantine Fault Tolerance (dBFT)) based on network load, validator behavior, and security requirements. Experimental results demonstrate that the proposed framework achieves zero-downtime cryptographic switching, improved transaction throughput, stable block finality, and enhanced quantum resilience. The proposed approach ensures a secure, scalable, and future-proof blockchain architecture that adapts to emerging quantum computing threats. The approach also has practical implications for building scalable, resilient, and quantum-secure blockchain systems applicable to decentralized finance, supply chain, and critical infrastructure applications.