Quantum Key Distribution (QKD) is a rising field of research that aims at solving a very common problem in computer security: the problem of cryptographic key exchange. Nowadays, key distribution problem is solved leveraging algorithms that allow to dynamically generate common secrets starting from shared information. For these algorithms security lies in the difficulty for an adversary to compute mathematical operations needed to recover the generated secret. Nevertheless, advent of quantum computers represents a huge concern for classical security, since it has been proved capable of solving these operations in polynomial time. QKD represents a possible solution to this problem, since it allows to exchange keys between two distant parties in a way that is considered secure against both classical and quantum attacks. Recent studies focus their attention on protocols and technologies needed to improve QKD between two parties, with little attention to practical integration in real contexts. This work proposes a different approach: QKD is here used in a softwarised network in order to be accessed from different security services or applications that may need it. The goal of this work is to outline main challenges that need to be faced when distributing QKD as a service for multiple clients. A QKD simulator has been developed to understand limits and characteristics of different protocols in such an environment. On the top of it, QKD ETSI standard has been implemented in order to realise a key server capable of distributing quantum distributed keys to different clients. The proposed work provides a new perspective, in which QKD can be used in cloud environments without taking care about the implementation complexity that it carries with it. Moreover, it outlines criticalities and challenges that needs to be faced in order to integrate QKD in such a systems.
Quantum Key Distribution (QKD) is a rising field of research that aims at solving a very common problem in computer security: the problem of cryptographic key exchange. Nowadays, key distribution problem is solved leveraging algorithms that allow to dynamically generate common secrets starting from shared information. For these algorithms security lies in the difficulty for an adversary to compute mathematical operations needed to recover the generated secret. Nevertheless, advent of quantum computers represents a huge concern for classical security, since it has been proved capable of solving these operations in polynomial time. QKD represents a possible solution to this problem, since it allows to exchange keys between two distant parties in a way that is considered secure against both classical and quantum attacks. Recent studies focus their attention on protocols and technologies needed to improve QKD between two parties, with little attention to practical integration in real contexts. This work proposes a different approach: QKD is here used in a softwarised network in order to be accessed from different security services or applications that may need it. The goal of this work is to outline main challenges that need to be faced when distributing QKD as a service for multiple clients. A QKD simulator has been developed to understand limits and characteristics of different protocols in such an environment. On the top of it, QKD ETSI standard has been implemented in order to realise a key server capable of distributing quantum distributed keys to different clients. The proposed work provides a new perspective, in which QKD can be used in cloud environments without taking care about the implementation complexity that it carries with it. Moreover, it outlines criticalities and challenges that needs to be faced in order to integrate QKD in such a systems.
Quantum Key Distribution (QKD), based on the laws of physics rather than the computational \ncomplexity of mathematical problems, provides a secure way of establishing symmetrical binary \nkeys between two geographically distant users. The keys are secure from eavesdropping during \ntransmission and QKD ensures that any third party’s knowledge of the key is reduced to a \nminimum. In recent years, a noticeable progress in the development of quantum equipment has \nbeen reflected through a number of successful demonstrations of QKD technology. While they \nshow the great achievements of QKD, many practical difficulties still need to be resolved, such as \nto provide better service differentiation. These networks are characterized as being multihop in \nnature where the consumption key rate is often higher than the charging key rate, which means that \nthe links are available for a limited period of time only. Such features impose several challenges \non the effective modeling and evaluation of reliability as well as finding appropriate Quality \nof Service (QoS) solution. This thesis focuses on research in the field of QKD for securing \nreal-time communication by supporting QoS in QKD networks including a novel QoS model \nand novel distributed reactive routing protocol to achieve high-level scalability and minimize the \nconsumption of key material used for securing routing data. \nAs research in QKD networks grows larger and more complex, the need for highly accurate and \nscalable simulation technologies becomes important to assess the practical feasibility and foresee \ndifficulties in the practical implementation of theoretical achievements. Due to the specificity of \nQKD link which requires optical/quantum and Internet connection between the network nodes, it \nis very costly to deploy a complete testbed containing multiple network hosts and links to validate \nand verify a certain network algorithm or protocol. The network simulators in these circumstances \nsave a lot of money and time in accomplishing such task. A simulation environment offers the \ncreation of complex network topologies, a high degree of control and repeatable experiments, \nwhich in turn allows researchers to conduct exactly the same experiments and confirm their results. \nThis thesis describes the design and implementation of QKD network simulation module which \nwas developed in the network simulator of version 3 (NS-3). The module supports simulation \nof QKD network in overlay mode or in a single TCP/IP mode. Therefore, it can be used for \nsimulation of other network technologies regardless of QKD. \nImplemented simulation model was used for verification of proposed QoS solution. A number \nof simulations were performed. The obtained data have confirmed the primary thesis of this study, \nthat it is possible to use real-time applications in QKD networks.
With the advent of quantum computing, classical cryptographic techniques—such as those underpinning Transport Layer Security (TLS)—are becoming increasingly vulnerable. Although post-quantum cryptographic algorithms are being developed, their long-term security remains uncertain. Quantum Key Distribution (QKD) offers a fundamentally different approach to key exchange and secure communication, as it bases security on the physics of quantum information rather than computational difficulty. This paper presents a practical simulation framework that integrates QKD-derived keys into the TLS protocol using the Pre-Shared Key (PSK) mode. The system employs a layered QKD architecture, implemented using QuNetSim, to generate and manage quantum keys, which are then distributed through a centralized Key Management Server (KMS). The proposed approach demonstrates how quantum-generated keys can be seamlessly integrated into the TLS protocol to enhance resilience against quantum attacks, providing a viable pathway toward post-quantum-secure communication.
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.
The emergence of the Quantum computing technologies is imposing greater threats on the existing cryptographic algorithms that rely heavily on the mathematical problems, creating a growing demand for quantum safe Communication. Even though Quantum Key Distribution (QKD) is a theoretically proven secure key exchange method against quantum attacks, it also faces several deployment challenges like scalability, cost, and interoperability limitations. A systematic review was conducted to examine the recent advancements in QKD technologies by analyzing the peer reviewed studies Published between 2021 to 2025 and classified according to protocol design, network architecture and deployment readiness. The review analyzed articles for a Comparison of the recent advancements in the field of Twin Field QKD, Continuous Variable QKD, Hybrid classical quantum networks and long-distance secure communication systems. Furthermore, the review also examined the Conjunction of QKD with the emerging security applications of 5G Networks, IOT environments, edge computing, fog Computing and Multimedia security systems. Despite of the significant technological advancements, the deployment of QKD is still under the constraints of scalability, lower key generation rates, cost of deployment, Synchronization issues, stability complexities, interoperability problems and standardization issues. Through a comprehensive evaluation of QKD protocols and network architectures, this study highlights the critical research gaps and provides future directions for the practical deployment of the QKD enabled secure communication networks.
In recent years, quantum computing technologies have steadily matured and have begun to find practical applications across various domains. One important area is network communication security, where Quantum Key Distribution (QKD) enables communicating parties to establish a shared secret that can then be used to generate symmetric keys for subsequent encryption and decryption. This study focuses on implementing and comparing two well-known QKD protocols, namely BB84 and E91, within an actual quantum computing environment. It also proposes the use of SX gate operations to generate uniform quantum superposition states. By leveraging the properties of quantum superposition and quantum entanglement, the study illustrates how communicating parties can securely obtain a shared secret while preventing adversaries from intercepting it. The experiments are conducted using the IBM Quantum Platform to demonstrate the feasibility of the BB84 and E91 protocols on actual quantum hardware. The evaluation considers several metrics, including entropy, Independent and Identically Distributed (IID), and error-rate verifications.
Secure communication makes the widespread use of telecommunication networks and services possible. With the constant progress of computing and mathematics, new cryptographic methods are being diligently developed. Quantum Key Distribution (QKD) is a promising technology that provides an Information-Theoretically Secure (ITS) solution to the secret-key agreement problem between two remote parties. QKD networks based on trusted relay nodes are built to provide service to a larger number of parties at arbitrary distances. They function as an add-on technology to traditional networks, generating, managing, distributing, and supplying ITS cryptographic keys. Since key resources are limited, integrating QKD network services into critical infrastructures necessitates effective key management. As a result, this article provides a comprehensive review of key management approaches for trusted-relay QKD networks. They are analyzed to facilitate the identification of potential strategies and accelerate the future development of QKD networks.