Blockchain systems built on classical cryptography face immediate risks from large-scale quantum computers, while purely quantum-based blockchains often rely on a single Private Key Generator (PKG) and incur heavy resource overheads. To overcome these issues, this paper proposes a hybrid quantum and post-quantum blockchain approach that removes single points of trust by using Distributed Key Generation and a dual-layer signature mechanism. This method integrates quantum digital signatures, rooted in the Fully Flipped Permutation problem, with classical post-quantum (lattice-based) cryptography, enabling users to switch between quantum and classical signatures according to security requirements and channel conditions. Delegated Proof-of-Stake with node behavior and Borda count has been incorporated to manage consensus, ensuring that witness nodes are regularly re-elected and malicious actors are penalized by distributing secret shares among multiple rotating witnesses. We eliminate the central vulnerability of a sole PKG while maintaining rigorous resistance to collusions. Our analytical model indicates that a fraction of transactions can use quantum signatures without system-wide bottlenecks, while the remaining transactions follow classical PQC paths with throughput approaching classical baselines under our modeling assumptions. Consequently, this hybrid method offers higher scalability, robust collusion resistance, and long-term security even under quantum-capable adversaries. This paper presents extensive theoretical analyses, probability models, and algorithmic complexities, demonstrating that our design provides resilient infrastructure that meets the key performance and security requirements of next-generation blockchain systems.
Blockchain systems built on classical cryptography face immediate risks from large-scale quantum computers, while purely quantum-based blockchains often rely on a single Private Key Generator (PKG) and incur heavy resource overheads. To overcome these issues, this paper proposes a hybrid quantum and post-quantum blockchain approach that removes single points of trust by using Distributed Key Generation and a dual-layer signature mechanism. This method integrates quantum digital signatures, rooted in the Fully Flipped Permutation problem, with classical post-quantum (lattice-based) cryptography, enabling users to switch between quantum and classical signatures according to security requirements and channel conditions. Delegated Proof-of-Stake with node behavior and Borda count has been incorporated to manage consensus, ensuring that witness nodes are regularly re-elected and malicious actors are penalized by distributing secret shares among multiple rotating witnesses. We eliminate the central vulnerability of a sole PKG while maintaining rigorous resistance to collusions. Our analytical model indicates that a fraction of transactions can use quantum signatures without system-wide bottlenecks, while the remaining transactions follow classical PQC paths with throughput approaching classical baselines under our modeling assumptions. Consequently, this hybrid method offers higher scalability, robust collusion resistance, and long-term security even under quantum-capable adversaries. This paper presents extensive theoretical analyses, probability models, and algorithmic complexities, demonstrating that our design provides resilient infrastructure that meets the key performance and security requirements of next-generation blockchain systems.
Blockchain systems are fundamentally dependent on classical cryptographic primitives, which are increasingly threatened by the rapid advancement of quantum computing. In cross-chain communication and interoperability protocols, where safe asset transfer and validation across heterogeneous networks are crucial, this danger is especially serious. Ensuring quantum-resilient interoperability is crucial for preserving security, trust, and long-term sustainability as next-generation blockchain ecosystems move toward multi-chain architectures. Relays, bridges, and atomic swaps are examples of existing interoperability methods that mostly rely on public-key cryptography, which is susceptible to quantum assaults like Shor's algorithm. In the post-quantum era, this vulnerability puts digital assets and cross-chain transactions at risk of compromise. This paper suggests a quantum-resilient cross-chain interoperability protocol framework to overcome this difficulty and allow safe and effective communication between various blockchain platforms. The suggested design incorporates post-quantum cryptographic techniques, such as hash-based and lattice-based signature algorithms, with consensus bridging and cross-chain transaction validation procedures. Additionally, a hybrid cryptographic transition model is presented to provide a progressive transition towards quantum-safe primitives while guaranteeing backward compatibility with current classical systems. The proposed structure greatly increases resilience against quantum attackers while maintaining interoperability efficiency, according to experimental evaluation. Robustness against replay attacks, signature forging, and key compromise under quantum threat models is confirmed by security analysis. The suggested protocol ensures strong and quantum-resilient interoperability in next-generation blockchain infrastructures by offering a scalable and future-ready foundation for safe multi-chain ecosystems.
The rapid development of quantum computing poses severe threats to traditional blockchain security mechanisms, while existing full-quantum blockchains face challenges regarding high hardware costs and limited scalability. To address these issues, this paper proposes a secure and practical semi-quantum blockchain system. Specifically, a Semi-Quantum Delegated Proof of Stake consensus mechanism is constructed by integrating an adapted semi-quantum voting protocol with the Borda count method and a malicious behavior penalty model. Furthermore, a lightweight transaction verification framework is designed based on semi-quantum key distribution, enabling classical users with limited quantum capabilities to participate securely. Theoretical analysis demonstrates that the system achieves unconditional security against quantum attacks while maintaining high throughput. These results indicate that the proposed asymmetric resource design significantly lowers hardware barriers compared to full-quantum schemes, effectively balancing security, practicality, and cost-effectiveness for post-quantum blockchain networks.
As emerging next-generation information technologies, blockchains have unique advantages in information transparency and transaction security. They have attracted great attentions in social and financial fields. However, the rapid development of quantum computation and the impending realization of quantum supremacy have had significant impacts on the advantages of traditional blockchain based on traditional cryptography. Here, we propose a blockchain algorithm based on asymmetric quantum encryption and a stake vote consensus algorithm. The algorithm combines a consensus algorithm based on the delegated proof of stake with node behaviour and Borda count (DPoSB) and quantum digital signature technology based on quantum state computational distinguishability with a fully flipped permutation ([Formula: see text]) problem. DPoSB is used to generate blocks by voting, while the quantum signature applies quantum one-way functions to guarantee the security of transactions. The analysis shows that this combination offers better protection than other existing quantum-resistant blockchains. The combination can effectively resist the threat of quantum computation on blockchain technology and provide a new platform to ensure the security of blockchain.
Blockchain technology has gained significant prominence in recent years due to its public, distributed, and decentration characteristics, which was widely applied in all walks of life requiring distributed trustless consensus. However, the most cryptographic protocols used in the current blockchain networks are susceptible to the quantum attack with rapid development of a sufficiently large quantum computer. In this paper, we first give an overview of the vulnerabilities of the modern blockchain networks to a quantum adversary and some potential post-quantum mitigation methods. Then, a new lattice-based signature scheme has been proposed, which can be used to secure the blockchain network over existing classical channels. Meanwhile, the public and private keys are generated by the Bonsai Trees technology withRandBasisalgorithm from the root keys, which not only ensure the randomness, but also construct the lightweight nondeterministic wallets. Then, the proposed scheme can be proved secure in random oracle model, and it is also more efficient than similar literatures. In addition, we also give the detailed description of the post-quantum blockchain transaction. Furthermore, this work can help to enrich the research on the future post-quantum blockchain (PQB).
Blockchain AI architectures stand at the nexus of distributed consensus and machine-driven intelligence, offering transformative applications across finance, supply chain, healthcare, and beyond. However, the emergence of scalable quantum computers threatens foundational cryptographic primitives—most notably, elliptic-curve and RSA-based schemes—that secure transaction integrity, key exchange, and smart-contract execution. This manuscript presents a comprehensive evaluation of quantum threat mitigation strategies tailored for blockchain AI systems. We examine three distinct approaches: (1) adoption of post-quantum cryptographic algorithms (lattice-based signatures and hash-based KEMs) that resist Shor’s algorithm; (2) integration of hybrid quantum-classical key distribution leveraging quantum key distribution (QKD) combined with classical post-quantum algorithms; and (3) deployment of trusted execution environments (TEEs) to isolate critical key operations from both classical and quantum side-channel attacks. Our mixed-methods methodology includes simulation on a 50-node blockchain AI testbed, processing 240,000 transactions over 24 hours, and statistical analysis of throughput, latency, and key-exchange performance. The results demonstrate that lattice-based schemes maintain 128-bit quantum security with a moderate performance overhead (~27 % throughput reduction, ~20 % increased latency), while hybrid QKD delivers information-theoretic security but incurs significant latency penalties (115 % higher than baseline). TEEs effectively mitigate side-channels with negligible additional overhead. We conclude by offering practical guidelines for phased deployment—beginning with immediate migration to lattice-based cryptography, followed by pilot QKD integration for high-security use cases—and outline future research directions.
The concept of blockchain technology has transformed the digital ecosystem to allow decentralized, transparent and immutable transactions in various sectors. Its security is closely dependent on classical cryptography like ECDSA and RSA to perform digital signatures and SHA-256 to achieve consensus, which are becoming more susceptible to quantum computing. The cryptographic principles underpinning blockchain could be compromised with the emergence of the quantum algorithms of Shor and Grover, endangering the integrity of transactions, authentication and consensus protocols. This paper discusses the implications that quantum computing could have on blockchain security, analyses vulnerabilities of current cryptographic primitives and assesses post-quantum cryptographic (PQC) protocols, including lattice-based protocols, hash-based protocols, and code-based protocols. To guarantee backwards compatibility, as well as a gradual upgrade process to quantum-resistant protocols, a hybrid migration approach that involves transactions with two signatures is suggested. Experimental analysis shows that PQC integration attains reasonable performance trade-offs, that preserve verification costs, block size growth, and throughput effects within feasible limits, and that zero-loss resilience is achieved during reorganization tests. The conclusion is that blockchains with PQC support can reach post-quantum levels of security without major operation interruption, and they provide a viable roadmap to moving towards distributed ledger systems that are future-ready.