Quantum-Proof Blockchain and Artificial Intelligence: An End-to-End Reference Architecture for Post-Quantum Distributed Ledger Resilience

Abstract

Quantum computing’s accelerating trajectory threatens the cryptographic foundations of every major blockchain network. Recent research demonstrates that fewer than 500 000 physical qubits could break ECC-256 in approximately nine minutes, while expert surveys place a 28–49% probability of a cryptographically relevant quantum computer (CRQC) emerging within ten years. This paper presents a layered reference architecture for end-to-end quantum-resilient distributed ledger systems, making three contributions: (1) a structured threat analysis applying STRIDE across blockchain architectural layers and post-quantum cryptography (PQC) migration phases; (2) a seven-layer reference architecture with per-layer interface specifications and dependency graph; and (3) a multi-chain quantum readiness assessment covering twelve major networks with fintech-specific migration strategies for decentralised finance (DeFi), stablecoins, tokenised real-world assets (RWA), and decentralised identity (DID). A critical finding is that blockchain’s primary quantum risk is real-time signature forgery upon CRQC arrival, not retroactive harvest-now-decrypt-later (HNDL) attacks on signatures. Cross-chain bridges, data availability layers, and Lightning Network payment channels are identified as the most critically neglected quantum attack surfaces.