Optical fibers form the backbone of our modern communication systems with ubiquitous use from connecting data centers to long distance links. In many cases, these links are used to transport highly sensitive information. QKD (Quantum Key Distribution) can be an ideal solution to protect data with the highest level of security. QKD systems are designed in such a way as to reduce the resources required for their implementation. They should be easily integrated into already existing optical communication networks without special requirements for optical cables.
Optical fibers form the backbone of our modern communication systems with ubiquitous use from connecting data centers to long distance links. In many cases, these links are used to transport highly sensitive information. QKD (Quantum Key Distribution) can be an ideal solution to protect data with the highest level of security. QKD systems are designed in such a way as to reduce the resources required for their implementation. They should be easily integrated into already existing optical communication networks without special requirements for optical cables.
It is well known that optical access networks are able to provide high data rates over long distances and to a reasonable number of users. Security and privacy are always a challenge for public accessible network infrastructures. Especially in time-division multiplexing passive optical networks (TDM-PONs), in which the downstream signal is broadcasted to all users connected via the same wavelength channel in a shared fiber link, privacy can be a critical concern. Although encryption at the application layer can provide a high level of security, this can be achieved only if the encryption key distribution is perfectly save. On the other hand, encryption on the physical layer such as quantum cryptography or, more precisely, quantum key distribution (QKD) is a very promising approach to achieve secure communication. However, there remain several issues that have to be solved before the quantum cryptography reaches the maturity level needed for a cost effective implementation in practical networks. In this paper, we address quantum key distribution (QKD) over passive optical access networks, which is an enabling technology required to cost efficiently deploy practical quantum encrypted data communication in the access area. We study different methods to integrate QKD systems in conventional optical access networks and quantitatively evaluate their suitability for a potential implementation.
Increasing incidents of cyber attacks and evolution of quantum computing poses challenges to secure existing information and communication technologies infrastructure. In recent years, quantum key distribution (QKD) is being extensively researched, and is widely accepted as a promising technology to realize secure networks. Optical fiber networks carry a huge amount of information, and are widely deployed around the world in the backbone terrestrial, submarine, metro, and access networks. Thus, instead of using separate dark fibers for quantum communication, integration of QKD with the existing classical optical networks has been proposed as a cost-efficient solution, however, this integration introduces new research challenges. In this paper, we do a comprehensive survey of the state-of-the-art QKD secured optical networks, which is going to shape communication networks in the coming decades. We elucidate the methods and protocols used in QKD secured optical networks, and describe the process of key establishment. Various methods proposed in the literature to address the networking challenges in QKD secured optical networks, specifically, routing, wavelength and time-slot allocation (RWTA), resiliency, trusted repeater node (TRN) placement, QKD for multicast service, and quantum key recycling are described and compared in detail. This survey begins with the introduction to QKD and its advantages over conventional encryption methods. Thereafter, an overview of QKD is given including quantum bits, basic QKD system, QKD schemes and protocol families along with the detailed description of QKD process based on the Bennett and Brassard-84 (BB84) protocol as it is the most widely used QKD protocol in the literature. QKD system are also prone to some specific types of attacks, hence, we describe the types of quantum hacking attacks on the QKD system along with the methods used to prevent them. Subsequently, the process of point-to-point mechanism of QKD over an optical fiber link is described in detail using the BB84 protocol. Different architectures of QKD secured optical networks are described next. Finally, major findings from this comprehensive survey are summarized with highlighting open issues and challenges in QKD secured optical networks.
The quantum encryption capable of creating encryption codes that unbreakable with key distribution schemes that can't be intercepted. The power of quantum entanglement can provide a way of instantaneous communication that non-interceptable. The quantum encryption method can be implemented together with scenarios of conventional encryption methods safely. The quantum cryptography will replace conventional key exchange mechanism by using the polarized photons using channels like optic fiber cables that can provide far secure communication. The present day data centers, which using for storing large amount of data, are connected with conventional cryptography and so it can be replaced with theoretically non-interceptable quantum cryptography mechanism as described in this paper. Obviously QKD will have uses in many areas of communication between remote data centers in cloud computing, defense networks etc.
The need to increase throughput and reduce the latency in the workload distribution and communications between different Data Centers (DCs) demands the use of dedicated or rented fibers. In view of enabling quantum secure communication in centralized and distributed DC, the integration of quantum key distribution (QKD) systems appears as a crucial milestone to safeguard data against quantum computing threats and the "Store-Now, Decrypt-Later" risk. Specifically, tailored technological solutions must be considered to enable practical deployment. In this context, continuous-variable QKD (CV-QKD) presents a promising approach due to its compatibility with optical systems and potential for cost savings and scalability. The adoption of photonic integrated circuits further enhances feasibility by enabling component miniaturization, reducing power consumption, and facilitating large-scale deployment. An important aspect to consider is optimizing fiber usage to support infrastructure sharing and resource efficiency. Therefore, the coexistence of the proposed QKD solutions with inter-DC communications must be carefully assessed. This invited contribution explores the integration of CV-QKD in DC networks to address flexible and efficient quantum secure connectivity. Envisioned co-propagation scenarios and associated challenges will be discussed, offering insights into the evolutionary path towards quantum secure DC infrastructures.
Optical communications have enabled high-speed data transmission over long distances. However, data are transmitted plain unless are encrypted on higher layers, e.g., IP and TCP, precisely because of: i) the high data rates; and ii) the need of secure key exchange between the end-points of the optical connection. Meanwhile, quantum enabled cryptography has emerged as a promising solution for securing communications by leveraging the principles of quantum mechanics which provides unlimited and unconditional security. Although Quantum Key Distribution (QKD) protocols can deliver quantum keys to distant end-points, there are scenarios where one of them is not within the security perimeter of the quantum network. This demonstration focuses on the intersection of optical communication and quantum security, highlighting the synergies between these two domains and their potential to ensure secure communication networks. We explore the integration of optical communication with quantum technologies and showcase how optical encryption using quantum keys retrieved from QKD and Quantum Random Number Generator (QRNG) systems is performed. Retrieved keys are expanded to the required rate and then used to encrypt the input data at line speed.
In a society based on the continuous exchange of sensitive data and information, the importance of secure and trustful communications is essential. Quantum key distribution (QKD) makes it possible to share data in an unconditionally secure way exploiting the basic principles of Quantum Mechanics [1]. During the last 30 years, many QKD protocols have been developed and tested, achieving long distance transmission [2] and secret key rates up to hundreds of Mbits per second [3]. However, this technology is still far from a large-scale deployment in existing fiber networks and telecom infrastructures, due to multiple factors: low secret-key rate, limited distance between users, lack of applications, high costs and high requirements in terms of low noise fiber links.