Decentralized system allows trustless collaboration among distributed participants directly without a central authority. Naturally, the system highly relies on cryptography to ensure information security and fairness. Classical cryptography is mostly based on the hardness assumption that can be solved by a quantum computer in polynomial time. Therefore, the research on quantum and post-quantum cryptography is becoming more and more important. This thesis explores how quantum information technology enhance the data-security in decentralized system from two different aspects. The first one involves the quantum solution of secure aggregation problem in multi-party secure computation without classical hardness assumptions. The quantum secure aggregation protocol uses decoy states and entangled quantum states to calculate the average of private numbers and detect inside or outside attacks. We analyze the protocol’s security and accuracy, also demonstrate numerical experiments to simulate the effectiveness. In the second one, we analyze the current quantum money protocols and propose the improved protocol which requires less quantum resources and support more functions. The cloud-based quantum money scheme allows the quantum money ecosystem to run on only semi-honest quantum cloud and classical participants and channels. Going a step further, the multi-channel currency scheme provides more kinds of secure transaction channels for choosing. In addition, we issue and transfer quantum currency on a real blockchain for the first time.
Decentralized system allows trustless collaboration among distributed participants directly without a central authority. Naturally, the system highly relies on cryptography to ensure information security and fairness. Classical cryptography is mostly based on the hardness assumption that can be solved by a quantum computer in polynomial time. Therefore, the research on quantum and post-quantum cryptography is becoming more and more important. This thesis explores how quantum information technology enhance the data-security in decentralized system from two different aspects. The first one involves the quantum solution of secure aggregation problem in multi-party secure computation without classical hardness assumptions. The quantum secure aggregation protocol uses decoy states and entangled quantum states to calculate the average of private numbers and detect inside or outside attacks. We analyze the protocol’s security and accuracy, also demonstrate numerical experiments to simulate the effectiveness. In the second one, we analyze the current quantum money protocols and propose the improved protocol which requires less quantum resources and support more functions. The cloud-based quantum money scheme allows the quantum money ecosystem to run on only semi-honest quantum cloud and classical participants and channels. Going a step further, the multi-channel currency scheme provides more kinds of secure transaction channels for choosing. In addition, we issue and transfer quantum currency on a real blockchain for the first time.
The integration of quantum cryptography and blockchain offers a transformative approach to enhance data security in cloud environments. Quantum cryptography, leveraging principles of quantum mechanics such as quantum key distribution (QKD), ensures unbreakable encryption by enabling secure key exchange. Simultaneously, blockchain technology introduces decentralization, transparency, and immutability, ensuring data integrity and preventing unauthorized tampering. This research explores the synergy between these technologies to develop a novel framework for cloud security. The proposed model leverages QKD for secure communication channels and blockchain-based distributed ledgers for verifying transactions and access control. Key contributions include a hybrid encryption mechanism using quantum keys, a consensus algorithm optimized for cloud operations, and integration strategies to mitigate quantum attacks. Performance evaluations demonstrate enhanced resilience against data breaches, improved key management, and seamless scalability for modern cloud architectures. This study establishes a secure, future-proof infrastructure that addresses emerging threats in the post-quantum era while ensuring trust, confidentiality, and data integrity in cloud ecosystems.
The advent of quantum computing poses an existential threat to contemporary cryptographic standards, particularly those securing decentralized blockchain networks and cloud infrastructures.Classical public-key cryptosystems such as RSA, ECC, and DH, which rely on factorization and discrete logarithm problems, are rendered obsolete by Shor's algorithm, necessitating the transition toward post-quantum cryptographic (PQC) solutions.This study explores the integration of PQC algorithms, including lattice-based, hash-based, code-based, multivariate, and isogeny-based cryptographic mechanisms, within blockchain-ledger technologies and cloud architectures to ensure long-term security against quantum adversaries.A comparative analysis is conducted to evaluate computational efficiency, key size implications, communication overhead, and security resilience under quantum attack models.The research highlights the adaptation of PQC within blockchain consensus mechanisms, smart contract execution, and cryptographic primitives such as digital signatures, zero-knowledge proofs, and secure multi-party computation (MPC).Additionally, it examines the impact of PQC on cloud security, addressing challenges in quantum-safe key exchange protocols, homomorphic encryption for secure computations, and cross-platform interoperability within hybrid quantum-classical cloud ecosystems.Real-world implementations and benchmarking data provide insights into the feasibility of large-scale adoption, shedding light on standardization efforts by NIST and industry consortia.The study concludes with future directions, emphasizing the need for efficient PQC algorithm optimization, lightweight cryptographic frameworks for IoT-driven blockchain applications, and scalable post-quantum identity management systems.By establishing quantum-resistant security frameworks, this research underscores the imperative need for early adoption to mitigate cryptographic vulnerabilities in the impending post-quantum era.
Quantum Key Distribution (QKD) has emerged as a revolutionary technology for secure communication, leveraging the principles of quantum mechanics to ensure the inviolability of cryptographic keys. Conventional QKD protocols often rely on centralized systems, which present challenges related to scalability, trust, and single points of failure. This review explores the security enhancements introduced by adopting a decentralized approach to QKD protocols. We analyze various decentralized QKD frameworks that eliminate the need for trusted third parties, leveraging blockchain technology and other distributed systems to enhance security, transparency, and robustness. In addition to assessing their performance, we examine how these decentralized models mitigate vulnerabilities such as key interception, node compromise, and denial-of-service attacks, which are prevalent in traditional centralized systems. Our review highlights advancements in the integration of decentralized QKD with classical cryptographic techniques, offering a comprehensive view of its potential to revolutionize secure communications in critical sectors. The decentralized approach to QKD represents a promising evolution towards more secure, scalable, and resilient quantum cryptography systems.
Digital interaction's expansion has created a necessity for safe and efficient data transfer. Standard encryption procedures can be cracked by sophisticated hacking techniques, and moreover, they will become obsolete in the future with the emergence of quantum computers. This article introduces a hybrid cryptography that consists of a secure channel based on quantum entanglement and a lightweight encryption scheme using XOR operations. Quantum key distribution allows for a tamper-proof key exchange, and at the same time, XOR encryption provides a very simple and quick encryption and decryption process. Thus, this double-layer security system not only ensures data privacy and data integrity but also makes it difficult for the attackers to use brute force or become one of the middle parties during the transaction. Moreover, the XOR algorithm can lower the number of calculations needed for the process, so the method can be utilized in real-time secure communication without any computational overhead. Simulation experiments are used for the evaluation of security, the time for the key generation, and the efficiency of encryption. Experiments of results underline the excellent protection of information interception and low technical overhead signalled in comparison with traditional methods of cryptography. This paper exemplifies one possible way to mix quantum and classical encryption techniques to build a secure communication system that is reliable, upgradable, and less vulnerable to attacks, which could eventually lead to a post-quantum era.
Quantum cryptography has emerged as a revolutionary technology for ensuring secure communication in the era of quantum computing. While existing research primarily focuses on theoretical frameworks and small-scale experimental setups, significant challenges remain in practical implementation, scalability, and security vulnerabilities. This study aims to bridge the gap between theory and real-world deployment by developing robust quantum cryptographic protocols that address key challenges such as noise management, side-channel attacks, and Trojan horse attacks. Additionally, we propose an optimized quantum key distribution (QKD) mechanism that ensures secure communication over long distances under realistic conditions. Our research integrates post-quantum cryptography with quantum cryptographic techniques to provide a hybrid security model that is resilient against both classical and quantum computing threats. By leveraging commercially available quantum hardware and advanced randomness extraction methods, this study contributes to the development of scalable, secure, and efficient quantum communication networks. The findings of this research will play a crucial role in advancing secure digital communication systems and fortifying data security in the post-quantum era.
The fast growth of quantum computing makes the old modes of cryptography, be it RSA or ECC, weak to quantum attacks, especially when it employs Shor's algorithm. Threatening also builds up on the post-quantum age regarding blockchain technology and its external cryptography, which secures reliable transactions and authentication. This study will address the importance of quantum resistant blockchain authentication protocols for the security of decentralized systems against any forward-looking quantum-enabled attacks. This paper goes through different classifications of post-quantum cryptography like lattice-based, hash-based, multivariate polynomial, and code-based cryptography, taking an effort to analyze their compatibility with blockchain use cases.[8] Moreover, we also introduce the innovative quantum-resistant authentication model designed to enhance security while not compromising upon efficiency.[2] [3] Our proposed model would ensure scalability and less computational overhead by partially providing immunity to quantum adversaries through its underlying use of post-quantum signature schemes and lightweight key exchange mechanisms. This research aims at laying the foundation for developing a secure blockchain ecosystem against quantum threats, heading toward a resistant future-proof decentralized infrastructure. [4] [5]