Abstract Blockchain is a distributed database which is cryptographically protected against malicious modifications. While promising for a wide range of applications, current blockchain platforms rely on digital signatures, which are vulnerable to attacks by means of quantum computers. The same, albeit to a lesser extent, applies to cryptographic hash functions that are used in preparing new blocks, so parties with access to quantum computation would have unfair advantage in procuring mining rewards. Here we propose a possible solution to the quantum era blockchain challenge and report an experimental realization of a quantum-safe blockchain platform that utilizes quantum key distribution across an urban fiber network for information-theoretically secure authentication. These results address important questions about realizability and scalability of quantum-safe blockchains for commercial and governmental applications.
Abstract Blockchain is a distributed database which is cryptographically protected against malicious modifications. While promising for a wide range of applications, current blockchain platforms rely on digital signatures, which are vulnerable to attacks by means of quantum computers. The same, albeit to a lesser extent, applies to cryptographic hash functions that are used in preparing new blocks, so parties with access to quantum computation would have unfair advantage in procuring mining rewards. Here we propose a possible solution to the quantum era blockchain challenge and report an experimental realization of a quantum-safe blockchain platform that utilizes quantum key distribution across an urban fiber network for information-theoretically secure authentication. These results address important questions about realizability and scalability of quantum-safe blockchains for commercial and governmental applications.
Abstract Optical networks are the backbone of today’s high-speed communication systems, but they can be attacked in many ways. Hackers might use advanced methods like wormhole attacks, Sybil attacks, or single-point failures to disrupt or take control of the network. Most current security systems rely on complex math to protect data. But with the development of quantum computers, those systems are no longer fully safe. Quantum computers could break these protections easily in the future. This problem can be solved by integrating two powerful technologies: Quantum Key Distribution (QKD) and blockchain This combination is called quantum-secured blockchain. This system removes the need for older, potentially breakable digital signatures, and instead uses methods that are resistant to quantum computer attacks. They also rely on new quantum materials and nanomaterials, which help in making better light sources, reducing signal loss and storing quantum information more reliably. AI and machine learning are now being used to speed up the discovery of these advanced materials such as superconductors, quantum dots and special optical fibers that are required to make the technology practical and scalable. This paper explains the different types of attacks that can occur in optical networks and the ways to protect optical networks using quantum-secured blockchain along. It gives the introduction to blockchain technology along with its security weaknesses, and then focuses on Quantum Key Distribution (QKD), which can make blockchain much stronger against attacks from powerful quantum computers. It also provides an overview of how quantum-secured blockchain works to secure optical communication networks.
The theory of QKD was first introduced in the 1980s. Initially, classical cryptographic methods were used to secure communication, but it was not a secure approach. Quantum Key Distribution (QKD) represents high-tech solution in the arena of secure and reliable cryptography and communication. Quantum key distribution make the use of quantum superposition and quantum entanglement to facilitate the secure interchange of cryptographic keys between two parties, with a theoretical invulnerability resistant to many threats, also including the threats that classical computing faces. On the other hand, blockchain is secured through cryptographic measures. A wide range of block chain applications rely on digital signatures and hash function which is easily traceable by quantum computers. The progress in quantum computing poses a potential risk of compromising existing cryptographic algorithms, in response to this challenge, proposals for potential solutions, such as the development of quantum-resistant blockchains, are being presented. The motivation of this study is to secure blockchain with the help of QKD. Fundamentally, understanding quantum key distribution is challenging. Hence, this research employs a Quantum Key Distribution Network simulator to analyze key distribution. The study focuses on illuminating the security concerns within blockchain and explores a potential solution through the deployment of quantum key distribution. Additionally, the research delves into the examination of a quantum key distribution network using a dedicated simulator.
Blockchain technology, renowned for its ability to securely store data, hashes, and signatures permanently, faces unprecedented challenges in secure Consumer IoT (CIoT) networks with the advent of quantum computing. This paper proposes a set of robust quantum-based protocols and techniques to address these challenges by enhancing the security, scalability, and reliability of CIoT systems in the face of quantum threats. Updating the blockchain infrastructure is imperative to ensure ongoing security, which involves forks or protocol adjustments to establish new post-quantum chains and addresses, requiring rapid data and asset migration by users. Blockchain guarantees data integrity through an immutable ledger of transactions distributed via cryptographic hashes. The proposed quantum protocols and techniques enhance scalability and reliability and address the unique security needs of both commercial and governmental applications in secure CIoT networks through immersive embedded cyber-physical systems. These include Quantum Currency Security Protocols, Distributed Ledger Data Blocks, Quantum Ledger Verification, Quantum Solutions for Middleman Attacks, and the integration of Elliptic Curve Cryptography (ECC)-based security measures. By integrating these methods, the proposed approach ensures robust protection against emerging quantum threats, thereby securing sensitive information and transactions.
Popularized by the Bitcoin cryptocurrency, blockchain technology establishes a decentralized digital framework that utilizes cryptographic and consensus protocols to secure data against unauthorized modification. Consequently, blockchain has found broad adoption across diverse fields, including finance, data management, healthcare, and digital asset governance. In the quantum computing era, a paramount objective for blockchain is to preserve its foundational advantages of cryptographic integrity and decentralized fault-tolerant resilience. In principle, quantum digital signatures and quantum Byzantine agreement protocols offer foundational security guarantees and tolerate up to one-half of malicious nodes for blockchain. However, the practical realization of such a quantum-enhanced blockchain remains a significant and multifaceted challenge. Here, we propose and experimentally demonstrate a fully operational hybrid quantum blockchain architecture built on photonic integrated circuits and deployed over commercially available classical telecommunications infrastructure. The system achieves a fault tolerance of nearly one-half, surpassing the classical limit, while reaching consensus on a timescale of seconds. A deployed food traceability application validates the practicality of the proposed architecture, achieving a throughput of approximately 500 transactions per second. This work establishes a foundation for practical quantum blockchains, enabling secure, scalable, and decentralized information processing in the emerging quantum era.
Cryptocurrency are decentralized digital money systems built on blockchain technology. The transactions are secured in these system using digital signatures based on public-key cryptography. Public-key cryptographic algorithms used for digital signatures, such as ECDSA, are vulnerable to quantum attacks. With over 2 trillion dollars market capitalization, the cryptocurrency industry will be at high risk in the Quantum Era. This paper evaluates the security of today's cryptocurrency blockchains under quantum attacks. It also reviews some of the proposed solutions to protect blockchains in the Quantum Era. Moreover, it presents a number of post-quantum digital signature schemes used to build quantum-safe blockchains. The result of this study shows that only a small portion of cryptocurrency can resist quantum attacks, while most of the cryptocurrencies used today are vulnerable to quantum attacks, with more than 99.8% of the total cryptocurrency market cap remains at risk. Useful recommendations are provided as a result of this study.
The emergence of quantum computing poses a significant threat to the security of blockchain protocols, primarily due to the vulnerability of current cryptographic algorithms to quantum attacks. This vulnerability jeopardizes the integrity of data and assets stored on blockchain networks, which currently hold hundreds of billions of dollars in cryptocurrencies and other digital assets. To mitigate this risk, various proposals and solutions have been presented in the literature. However, most existing proposals are either theoretical, rely on large quantum key distribution (QKD) networks, or advocate for the development of new quantumresistant blockchain networks from scratch. Despite the understanding of the quantum threat and potential solutions, practical implementations are scarce. A recent survey paper addresses this gap by proposing an end-to-end framework for achieving postquantum resistance in existing blockchain networks. The framework, outlined in the survey, is compatible with Ethereum-based networks and offers practical solutions for key generation, secure communication between nodes, and transaction verification. Notably, the framework utilizes quantum entropy for key generation, and post-quantum TLS connections, and introduces post-quantum signatures in transactions. Additionally, it incorporates on-chain verification mechanisms using Solidity smart contracts and modified EVM Opcode. This chapter represents a significant contribution to the field by providing a comprehensive overview of existing solutions and proposing a practical framework for enhancing blockchain security against quantum threats.