Contents


Preface

Quantum cryptography (QC) is a special powerful tool for the wide spectrum of security applications based on both fundamental and applied principles of quantum

mechanics, which allows two subscribers to generate, exchange, and process perfectly unique keys via a potentially insecure and intercepting quantum channel. Proposed 35 years ago, quantum key distribution (QKD), as a process to realize the advantages of QC, attracts more and more attention. Significant progress has been made in both its theory and practice from many points of view. The present book has four exclusive chapters. All chapters are focused on the most important provable developments in this critically important area of humankind wide spectra communications, because transferring information in a secure and private manner

QKD systems with carrier modulation coding are prominent representatives of classical fiber telecommunication systems based on the principles of microwave photonics, with their inherent advantages and disadvantages. If the former can be attributed to the universality of modulation schemes, and the undoubted provision of a high signal-to-noise ratio in both quantum and synchronization channels of almost any length, the latter will begin to manifest with a constant increase in the range of quantum communication channels and the duration of the connection. First of all, they should include polarization distortion and chromatic dispersion. The introductory chapter focuses on monitoring the chromatic dispersion of the synchronization channel, which is controlled by the same generators as Alice and Bob's quantum channels, but in the absence of phase switching corresponding to the polarization state of the photons. In particular, the monitoring of chromatic dispersion in the synchronization channel is considered with the possibility of eliminating the influence of polarization distortions and using a clock frequency equal to the phase switching frequency, with its separation in a fiber Bragg grating

Optical network security is attracting increasing research interest. Currently, a software-defined optical network (SDON) has been proposed to increase network intelligence (e.g., flexibility and programmability), which is gradually moving towards industrialization. However, varieties of new threats are emerging in SDONs. Data encryption is an effective way to secure communications in SDONs. In the first chapter of the book "Quantum Key Distribution over Software Defined Optical Networks," an architecture of QKD over SDONs, based on the QKD enabling technologies, is presented. The resource allocation problem is elaborated in detail and is classified into wavelength allocation, time-slot allocation, and secret-key allocation problems in QKD over SDONs. Finally, several open issues and

Free-Space Optical Quantum Key Distribution (FSO-QKD) systems present an innovative way for sharing secure information between two parties located at ground stations, spacecraft, or aircraft. However, these scenarios present several challenges regarding the hardware, protocols, and techniques used that must be solved to enhance the performance parameters (security level, distance link,

is a key ingredient to many aspects of society.

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challenges are discussed.
