Blockchain Papers

Jincheng Zhang

This paper proposes a novel blockchain consensus mechanism termed "Distributed Proof-of-Work with Quantum Key Distribution" (DPW-QKD). The core idea is to leverage quantum key distribution (QKD) to replace computationally intensive hash functions in traditional Proof-of-Work (PoW) systems, thereby significantly reducing energy consumption. The system operates by nodes generating cryptographic keys through QKD, which are then utilized in a distributed QKD protocol to verify transaction validity. This approach eliminates the need for miners to solve complex cryptographic puzzles, creating a more energy-efficient and potentially more secure consensus model. The paper outlines the architecture, key components, and operational principles of the DPW-QKD system, highlighting its advantages and potential challenges. Mathematical formulations are presented to illustrate the key processes and security considerations within the system. The research aims to explore a viable pathway towards a sustainable and robust blockchain technology, driven by the inherent security of quantum mechanics.

Rachida Hireche, Houssem Mansouri, Yasmine Harbi, Al‐Sakib Khan Pathan · 5 authors

Background: In recent years, the Internet of Medical Things (IoMT) has transformed the healthcare sector through real-time patient monitoring and continuous data collection.However, transmitting sensitive medical information over public networks exposes IoMT systems to significant security threats, while emerging quantum computing technologies challenge the reliability of traditional cryptographic systems.Objective: The objective of this study is to propose PQAC-BIoMT, a secure and robust model for remote user authentication and access control in IoMT environments, capable of withstanding both conventional and quantum attacks.Methods: This article proposes a decentralized authentication framework that integrates post-quantum cryptography using Kyber Public-Key Encryption (Kyber-PKE) into blockchain-based smart contracts.Fog computing nodes are used to reduce the authentication latency and improve the system scalability.A role-based authorization mechanism is integrated to link user identities to functional roles and enforce authorization to medical data and system resource access.Formal security verification is conducted using Burrows-Abadi-Needham (BAN) logic to validate the correctness of authentication, and the Automated Validation of Internet Security Protocols and Applications (AVISPA) tool is used to assess resistance to known attacks.PQAC-BIoMT is further evaluated through a comparative analysis of the computational load, energy consumption and security properties.Results: Our security analysis demonstrates that PQAC-BIoMT effectively resists common attacks while providing quantum-resistant protection against them.The performance evaluation shows that the proposed scheme achieves relatively lower computational and energy overhead compared to existing approaches, making it suitable for resource-constrained IoMT devices.Conclusion: The proposed PQAC-BIoMT scheme delivers a secure, quantum-resilient authentication and authorization mechanism for IoMT systems, enhancing both data protection and operational efficiency, which can support practical deployment in real-world IoMT applications.

Stian Lybech, Eun-Young Kang, Riccardo Tonello, Anders Dalskov

This paper develops a model of a smart-contract language for a blockchain architecture with off-chain components. Off-chain components are pieces of smart contracts that execute at designated locations outside of the network of blockchain nodes, but remain synchronised with the on-chain contract state. They react to changes to the on-chain state, but may also notify the on-chain component about events in the world, e.g. stock prices, weather data etc., or even act as a bridge between different blockchains. This affords greater flexibility for the developer, but may also enable new vulnerabilities. As a concrete example, we use the model to study the problem of ensuring integrity and secrecy of data between the on-chain and off-chain components, using static information flow control techniques. This fails, even in the absence of a loop construct, because off-chain components act as separate threads and can encode a blocking construct e.g. through recursive method calls. We end the paper with a discussion of possible ways to remedy this situation.

Abdullah Alabdulatif

The rapid digitalisation of healthcare has accelerated the adoption of telemedicine, Electronic Health Records (EHRs), and the Internet of Medical Things (IoMT), transforming healthcare delivery into a highly interconnected and patient-centric ecosystem. In response to growing concerns about data security, privacy, and interoperability, blockchain technology has emerged as a promising solution for its decentralization, immutability, auditability, and secure access control. However, many existing blockchain infrastructures rely on classical cryptographic primitives, including RSA- or elliptic-curve-based public-key mechanisms and cryptographic hash functions such as SHA-256, whose relevant security properties may be affected by sufficiently powerful quantum attacks. This review investigates the convergence of blockchain and quantum technologies to address emerging security threats in e-health systems. A structured literature review was conducted in accordance with the PRISMA 2020 guidelines using the IEEE Xplore, PubMed, ACM Digital Library, Google Scholar, and Crossref databases, covering studies published between January 2018 and June 2025. Following a systematic screening and eligibility-verification process, 57 relevant studies were selected and analyzed. The review evaluates quantum-resilient security mechanisms, including Quantum Key Distribution (QKD), Quantum Random Number Generation (QRNG), and NIST-standardized Post-Quantum Cryptography (PQC) algorithms specified in FIPS 203, FIPS 204, and FIPS 205. Based on the identified research gaps in the state of the art, this study also proposes a novel four-layer Quantum-Blockchain Security Architecture (QBSA) designed for secure healthcare environments. The analysis further reveals significant challenges associated with lightweight PQC deployment for IoMT devices, interoperability standardization, quantum hardware limitations, and regulatory compliance in cross-institutional healthcare systems. The findings highlight the necessity of integrating quantum-resilient cryptographic frameworks with blockchain infrastructures to support the development of secure, scalable, and patient-centric next-generation e-health ecosystems.