Using Quantum Key Distribution for Securing Real-Time Applications

Quantum Key Distribution (QKD), based on the laws of physics rather than the computational complexity of mathematical problems, provides a secure way of establishing symmetrical binary keys between two geographically distant users. The keys are secure from eavesdropping during transmission and QKD ensures that any third party’s knowledge of the key is reduced to a minimum. In recent years, a noticeable progress in the development of quantum equipment has been reflected through a number of successful demonstrations of QKD technology. While they show the great achievements of QKD, many practical difficulties still need to be resolved, such as to provide better service differentiation. These networks are characterized as being multihop in nature where the consumption key rate is often higher than the charging key rate, which means that the links are available for a limited period of time only. Such features impose several challenges on the effective modeling and evaluation of reliability as well as finding appropriate Quality of Service (QoS) solution. This thesis focuses on research in the field of QKD for securing real-time communication by supporting QoS in QKD networks including a novel QoS model and novel distributed reactive routing protocol to achieve high-level scalability and minimize the consumption of key material used for securing routing data. As research in QKD networks grows larger and more complex, the need for highly accurate and scalable simulation technologies becomes important to assess the practical feasibility and foresee difficulties in the practical implementation of theoretical achievements. Due to the specificity of QKD link which requires optical/quantum and Internet connection between the network nodes, it is very costly to deploy a complete testbed containing multiple network hosts and links to validate and verify a certain network algorithm or protocol. The network simulators in these circumstances save a lot of money and time in accomplishing such task. A simulation environment offers the creation of complex network topologies, a high degree of control and repeatable experiments, which in turn allows researchers to conduct exactly the same experiments and confirm their results. This thesis describes the design and implementation of QKD network simulation module which was developed in the network simulator of version 3 (NS-3). The module supports simulation of QKD network in overlay mode or in a single TCP/IP mode. Therefore, it can be used for simulation of other network technologies regardless of QKD. Implemented simulation model was used for verification of proposed QoS solution. A number of simulations were performed. The obtained data have confirmed the primary thesis of this study, that it is possible to use real-time applications in QKD networks.