This paper discusses quantum theories, protocols that are currently being readied for practical use and unproven concepts that might breakthrough at some point in the future. It will discuss Quantum Key Distribution and several of its protocols and applications, authentication methods and protocols, and unconditional security. Moreover, it takes and in-depth look at key recycling, quantum digital signatures (QDS), quantum fingerprinting – which is basically the quantum equivalent of a hashing process, and finally, entity authentication and whether it is achievable via entanglement.
This paper discusses quantum theories, protocols that are currently being readied for practical use and unproven concepts that might breakthrough at some point in the future. It will discuss Quantum Key Distribution and several of its protocols and applications, authentication methods and protocols, and unconditional security. Moreover, it takes and in-depth look at key recycling, quantum digital signatures (QDS), quantum fingerprinting – which is basically the quantum equivalent of a hashing process, and finally, entity authentication and whether it is achievable via entanglement.
Quantum cryptography represents a revolutionary approach to securing communications by harnessing the principles of quantum mechanics. This paper provides an overview of the state-of-the-art techniques in quantum cryptography, focusing on key areas such as Quantum Key Distribution (QKD), quantum secure direct communication (QSDC), and quantum digital signatures. We explore the advancements in QKD protocols, including BB84, E91, and the recently proposed measurement-device-independent QKD (MDI-QKD), which aim to counteract practical threats such as detector loopholes. Additionally, we discuss the integration of quantum cryptography with classical systems, the challenges in implementing quantum-safe protocols, and the efforts towards achieving large-scale quantum networks. Finally, we examine the future directions of quantum cryptography, addressing emerging technologies such as quantum repeaters, quantum memory, and hybrid quantum-classical encryption schemes, which are expected to enhance the security and scalability of quantum communication systems. The paper concludes with insights into the practical deployment of quantum cryptography and its potential to reshape the landscape of global cybersecurity in the coming decades.
Quantum cryptography (QC) as an important technology to protect the security of the future network communication, has gained extensive attention from both academia and industry in recent years. This paper provides a concise up-to-date review of QC, including Quantum key distribution (QKD), Quantum authentication, Quantum public-key cryptography (QPKC), and so on. Our aim is to pave a comprehensive and solid starting ground for interested readers. We firstly clarify the definition of QC. Secondly, we present the current understanding of QC from different levels, including the basic knowledge of quantum information processing, QC protocols and the attacks in QC. Finally, we discuss the challenges and opportunities in this hopeful field.
This paper provides an overview of the basic principles, types, recent works, and applications of quantum digital signatures. The security of traditional digital signature schemes is compromised by the rise of quantum computing, leading to a need for post-quantum cryptography. Quantum digital signatures, which rely on the principles of quantum mechanics, offer a potential solution to this problem. This paper aims to provide a comprehensive overview of quantum digital signatures and post-quantum digital signatures. The paper introduces the basic principles of quantum mechanics, then explains key distribution in quantum digital signatures. The paper then provides a detailed description of both quantum and post-quantum digital signatures, including their differences and applications. Finally, the paper summarizes the main findings in the field, highlights potential future directions, and discusses challenges that humans must address. In addition, the paper examines the widespread applications of quantum digital signatures and post-quantum digital signatures in various fields such as Bitcoin, smart city blockchain, and finance. Finally, the paper summarizes the key findings in the field, highlighting potential future directions and discussing challenges that humans must address. Overall, this paper aims to provide readers with a comprehensive understanding of quantum digital signatures and post-quantum digital signatures and their applications in various domains.
Quantum digital signatures (QDSs), generating correlated bit strings among three remote parties for signatures through quantum law, can guarantee nonrepudiation, authenticity, and integrity of messages. Recently, a one-time universal-hashing QDS framework, exploiting the quantum asymmetric encryption and universal hash functions, has been proposed to significantly improve the signature rate and ensure unconditional security by directly signing the hash value of long messages. However, similar to quantum key distribution, this framework utilizes keys with perfect secrecy by performing privacy amplification that introduces cumbersome matrix operations, thereby consuming large computational resources, causing delays, and increasing failure probability. Here, we prove that, different from private communication, imperfect quantum keys with partial information leakage can be used for digital signatures and authentication without compromising the security while having eight orders of magnitude improvement on signature rate for signing a megabit message compared with conventional single-bit schemes. This study significantly reduces the delay for data postprocessing and is compatible with any quantum key generation protocols. In our simulation, taking two-photon twin-field key generation protocol as an example, QDS can be practically implemented over a fiber distance of 650 km between the signer and receiver. For the first time, this study offers a cryptographic application of quantum keys with imperfect secrecy and paves a way for the practical and agile implementation of digital signatures in a future quantum network.
Extending device-independent (DI) quantum cryptography to composably support all fundamental information security objectives is crucial for secure quantum networks. Achieving this goal requires composable quantum digital signatures (QDSs), which support integrity, authenticity, and nonrepudiation when integrated into quantum networks. Yet existing QDS protocols generally rely on assumptions about the underlying quantum devices, while their security analyses remain largely restricted to stand-alone settings, leaving related-key attacks on the underlying linear feedback shift register (LFSR)-based Toeplitz authentication unaddressed. Here, we establish the first composable security framework for QDS within constructive cryptography, and realize the corresponding ideal QDS resource by developing a DI-QDS protocol employing one-time universal hashing and multi-channel multiplexing. We further derive a related-key security bound for the underlying LFSR-based Toeplitz authentication, thereby establishing unforgeability while extending the forgery boundary considered in previous QDS security analyses. We also demonstrate the practical feasibility of our DI-QDS protocol under realistic quantum network conditions in the finite-size regime, with numerical simulations showing that it enables efficient signing of multibit documents over metropolitan-scale distances. Our results establish QDS as a composable cryptographic primitive and extend DI quantum cryptography to support the full range of information security objectives with composable security guarantees in future quantum networks.