Quantum-key-distribution (QKD) networks can theoretically generate quantum secret keys that are completely secure for an entire communication system. The rate of key distribution is low and decreases exponentially with increasing distance. A classic trusted relay (CTR) uses additional keys to enhance security distance in QKD networks. In practice, the assurance of security for certain relay nodes is still lacking, despite the fact that CTR requires that all nodes be trusted. Owing to channel unreliability, system faults accumulate during the key relay, thereby increasing the probability of CTR failing to distribute the secret key. The failure of a successful key relay would then result in the subsequent destruction of all the keys involved in the process, which leads to the wasting of the quantum secret key and reduction system encryption. Accordingly, reducing the impact of CTR failures and realising the key security distribution of remote quantum networks have become new challenges that require the development of a new survivability scheme. In this study, a software-defined networking (SDN) technique is introduced to circumvent this drawback by utilising the flexibility provided by the SDN paradigm for better QKD network management efficiency. In particular, a novel survivability model called software-defined quantum key relay failure (SDQKRF) is proposed in this paper in which a new function is developed and added to the SDN controller. According to the simulation results, SDN over a QKD network using the SDQKRF model is more reliable and performs better in terms of the key generation ratio, key utilisation rate, recovery after failure, avalanche effect, and service blocking rate than a regular QKD network without the SDQTRF model.
Quantum-key-distribution (QKD) networks can theoretically generate quantum secret keys that are completely secure for an entire communication system. The rate of key distribution is low and decreases exponentially with increasing distance. A classic trusted relay (CTR) uses additional keys to enhance security distance in QKD networks. In practice, the assurance of security for certain relay nodes is still lacking, despite the fact that CTR requires that all nodes be trusted. Owing to channel unreliability, system faults accumulate during the key relay, thereby increasing the probability of CTR failing to distribute the secret key. The failure of a successful key relay would then result in the subsequent destruction of all the keys involved in the process, which leads to the wasting of the quantum secret key and reduction system encryption. Accordingly, reducing the impact of CTR failures and realising the key security distribution of remote quantum networks have become new challenges that require the development of a new survivability scheme. In this study, a software-defined networking (SDN) technique is introduced to circumvent this drawback by utilising the flexibility provided by the SDN paradigm for better QKD network management efficiency. In particular, a novel survivability model called software-defined quantum key relay failure (SDQKRF) is proposed in this paper in which a new function is developed and added to the SDN controller. According to the simulation results, SDN over a QKD network using the SDQKRF model is more reliable and performs better in terms of the key generation ratio, key utilisation rate, recovery after failure, avalanche effect, and service blocking rate than a regular QKD network without the SDQTRF model.
Quantum key distribution (QKD) holds the potential of providing long-term integrity and confidentiality for data and communications. Currently, many fiber-based QKD systems have been commercialized and several QKD networks have been deployed. Given the high cost and complexity of QKD network deployment, QKD as a service (QaaS) becomes a promising pattern for future QKD networks. The QaaS concept is that multiple users can apply for QKD services to obtain their required secret-key rates (SKRs) from the same QKD network infrastructure instead of deploying their dedicated QKD networks. Accordingly, how to provide efficient and flexible QaaS for fulfilling the SKR requirements of multiple users over a QKD network infrastructure becomes a new challenge. This study introduces the software defined networking (SDN) technique to overcome this challenge, since SDN can add flexibility together with efficient QKD network management. A new framework of SDN for QaaS (SDQaaS) is proposed, where the QaaS functions are developed in the SDN controller. We present the protocol extension, intercommunication workflow, and routing and SKR assignment strategy for QaaS implementation in the SDQaaS framework. We also establish a SDQaaS experimental testbed and perform the numerical simulation to verify our presented approaches. Experimental results demonstrate that our presented approaches can achieve efficient and flexible QaaS over the QKD network. Moreover, simulation results indicate that the success probability of QKD service requests can be increased via lowering the flexibility of SKR requirements for QKD service creation, sacrificing more cost to produce higher SKR over the QKD network, or gradually reducing SKR requirements with the modification of QKD service.
Modern communication networks can be flexibly shaped and controlled using Software Defined Networking (SDN) paradigm. However, besides unprecedented functional benefits, this solution exploits an architectural single point of failure. Securing the communication among SDN functional element is therefore a critical requirement for improving the network reliability. A novel approach to secure communications is provided by Quantum Key Distribution (QKD) that is a physical layer technology capable to securely deliver symmetric encryption keys leveraging on quantum physic properties. Our research demonstrates how to provide unconditionally secure communication at SDN level dramatically improving the reliability of the communication network itself.
The ability to protect information has always played an important role in the evolution of civilizations, and even in the history of mankind as a whole. Safe and reliable communications have become an essential component of people’s lives in the era of modern digital technologies, when all spheres and areas of activity, from defense and government to business and social communications, are unthinkable without real-time data exchange. Classical methods of cryptographic protection have long been used to ensure the security of data transmission, but with the explosive growth in computing power and the emerging development of quantum computers, many traditional solutions have become vulnerable. Quantum Key Distribution (QKD) is a popular research area at the moment, due to its use of the laws of quantum mechanics, and thus it is possible to provide a completely secure level of encryption. But traditional quantum communication protocols have their limitations, including low key generation rates, scalability problems in large networks, and vulnerabilities to various forms of cyberattacks in the network layer. Therefore, in this work we propose a new adaptive quantum key distribution algorithm using software-defined networking (SDN) technology. The main idea of the proposed approach is to introduce some level of redundancy in the key generation stage, which increases the throughput, robustness, and adaptability of multi-node quantum networks. In addition, the SDN control layer allows dynamic routing and resource management and quick response to changes in the network state, making the system more resistant to denial-of-service and eavesdropping attacks. Evaluating our solution in comparison with BB84, we show that the new algorithm provides better performance without losing its security level, making the work a step towards creating a working quantum-secure communication system.
Quantum-key-distribution (QKD) networks can provide absolutely secure keys for the entire communication system in theory. At present, the key-distribution rate is relatively low, and the key-distribution rate decreases exponentially as the distribution distance increases. The trusted-relay scheme commonly used in existing QKD networks achieves the purpose of extending the security distance by consuming additional keys. Since the channel is unreliable, the key-relay process will accumulate system errors to a certain extent, increasing the probability of key-relay failure. In some high-bit-error-rate network scenarios such as wireless networks and disaster environments, the channel-error rate is as high as 30–50%. And in these scenarios, there are usually a large number of confidential messages that need to be delivered. However, the key-management mechanism of the current QKD system does not consider the scenario of key-relay failure. If the key is not successfully relayed, all the keys participating in the relay process will be destroyed, including the key that has been successfully relayed before. This situation causes the key to be wasted and reduces the encryption capability of the system. In this paper, we proposed the quantum-key-recycling (QKR) mechanism to increase the number of keys available in the network and introduced a secure service grading mechanism to properly reuse the recycled keys. The QKR mechanism can be regarded as a key-management mechanism acting on the point-to-point QKD system, and the mechanism is designed for a classical channel to reuse the key resources. A post-processing method for recycled keys is proposed to improve the security of the keys. Simulation results show that the QKD network using the key-recycling strategy is about 20% higher in key-utilization rate than the traditional QKD network without the QKR mechanism, and about 10% higher in-service security coverage.
With the advent of powerful quantum computers, an emerging quantum-resilient security mechanism within existing networks is crucial. Thus, Quantum Key Distribution (QKD), which generates symmetric secret keys with Information-Theoretical Security (ITS) for secure point-to-point communication, is present as a solution. Despite QKD’s potential, its deployment is challenging due to significant investment and infrastructure requirements. Using state-of-the-art technology, the maximum distance between nodes is limited to hundreds of kilometers, necessitating multiple nodes to relay keys. For now, QKD Network (QKDN) relies on software-defined networking (SDN) and a central orchestrator, but this centralized approach has limitations. Hence, the main challenge is to select an efficient path between key relays to avoid communication failure. To address these challenges, a more distributed approach could be envisioned. In this paper, we propose to leverage one of the distributed routing protocols, OSPF, to redefine and improve the current architecture. We propose a novel QKDN-based OSPF (Open Shortest Path First) architecture for efficient key relay routing, offering a completely different dimension to the overall network management: we modify QKDN architecture to exploit the OSPF networks and present a QKD-enabled OSPF version capable of computing the best path for key relay, offering a cost-effective and scalable solution for widespread QKD adoption.
Software-Defined Networking (SDN) is an emerging networking paradigm that decouples the control and data plane in order to enable programmable and flexible networks, optimizing its applications and advancing computer systems. It does so through its architecture, a key part of which is a centralized network management through open interfaces that revolutionizes the way in which networks are designed and makes them more agile and versatile to the evolving needs of modern and future applications services. This also means, however, that there is now a centralized point of attack that is a major vulnerability, threatening the security of the entire network. With such an advanced network paradigm, it requires a security system that will mitigate these risks and warrant long-term security. In attempts to allow secure communications within the network, this research proposes the implementation of Quantum Key Distribution (QKD), leveraging quantum mechanics to secure the network against any computational advancements in the future. QKD is a recent cryptographic system that includes a traditional-computational channel and a physical-quantum channel to generate and distribute keys between parties. It uses the principles of quantum mechanics including entanglement and superposition to ensure that the physical layer cannot be compromised computationally. QKD provides confidentiality and privacy of information and communication. Moreover, it is resistant to technological advancements. The implications of QKD significantly enhance SDN security through its protection against attacks, efficient key distribution, reliable network orchestration, and data integrity, creating an architecture that establishes stable communication channels that are resistant to cyber threats.