In recent decades researches of quantum cryptography has become one of the most promising area in the field of information security. Quantum key distribution (QKD) provides reliable methods for exchanging keys using the principles of quantum mechanics, ensuring a high level of security in data transmission. Of particular interest is the application of QKD in space communications, where communication channels can cover significant distances - from Earth to satellites. The most promising waveband for quantum communications and cryptography now is subterahertz (sub-THz) frequency range from 100 GHz to 1 THz. The influence of the atmosphere on the efficiency of quantum key distribution is essential for this waveband. The report provides an overview of the influence of the atmosphere on quantum key distribution within sub- THz frequency range. The advantages and disadvantages are analyzed, as well as solutions for increasing the efficiency of quantum key distribution.
In recent decades researches of quantum cryptography has become one of the most promising area in the field of information security. Quantum key distribution (QKD) provides reliable methods for exchanging keys using the principles of quantum mechanics, ensuring a high level of security in data transmission. Of particular interest is the application of QKD in space communications, where communication channels can cover significant distances - from Earth to satellites. The most promising waveband for quantum communications and cryptography now is subterahertz (sub-THz) frequency range from 100 GHz to 1 THz. The influence of the atmosphere on the efficiency of quantum key distribution is essential for this waveband. The report provides an overview of the influence of the atmosphere on quantum key distribution within sub- THz frequency range. The advantages and disadvantages are analyzed, as well as solutions for increasing the efficiency of quantum key distribution.
The ultra-secure quantum network leverages quantum cryptography to deliver unsurpassed data transfer security. In principle, the well-known quantum key distribution (QKD) achieves unconditional security, which raises concerns about the trustworthiness of 6G wireless systems in order to mitigate the gap between practice and theory. The long-distance satellite-to-ground evolving quantum network distributes keys that are ubiquitous to the node on the ground through low-orbit satellites. As the secret key sequence is encoded into quantum states, it is sent through the atmosphere via a quantum channel. It still requires more effort in the physical layer design of deployment ranges, transmission, and security to achieve high-quality quantum communication. In this paper, we first review the quantum states and channel properties for satellite-based quantum networks and long-range quantum state transfer (QST). Moreover, we highlight some challenges, such as transmissivity statistics, estimation of channel parameters and attack resilience, quantum state transfer for satellite-based quantum networks, and wavepacket shaping techniques over atmospheric channels. We underline two research directions that consider the QST and wavepacket shaping techniques for atmospheric transmission in order to encourage further research toward the next generation of satellite-based quantum networks.
The article analyzes the main trends in the field of optimization of information transmission processes using quantum methods. It is shown that numerical modeling of satellite optical communication systems is necessary in order to determine the most effective modes and parameters of communication equipment. This article is devoted to the problem of developing a software package for calculating the characteristics of a communication channel between a ground station and an artificial Earth satellite. A detailed description of the basic functions of the developed software package for calculating the characteristics of an Earth-satellite optical communication channel protected by QKD technology is presented. Based on numerical modeling using the developed software package, a comprehensive study of the influence of atmospheric losses, as well as various parameters of the receiving and transmitting equipment of both the ground station and the satellite, is carried out. In particular, when modeling the efficiency of satellite quantum key distribution and an optical communication channel, atmospheric phenomena such as refraction, absorption, aerosol scattering, as well as the parameters of the QKD equipment were taken into account. Modeling revealed the need to take into account many aspects to achieve maximum efficiency of the QKD in real conditions. It is shown that the developed software for flexible modeling of various scenarios for using atmospheric optical communications opens up new opportunities for research and practical application of quantum technologies in the field of information security, which is important for data protection in the face of growing cybersecurity threats. It is shown that the capabilities of the developed software package can contribute to the creation of standardized approaches to assessing and improving quantum key distribution systems.
Abstract Quantum key distribution (QKD) is one of the major applications of quantum information technology. It can provide ultra‐secure key distribution with security guaranteed by the laws of quantum physics. Quantum key distribution is necessary to protect data transmission from quantum computing attacks in future communication networks. The laws of quantum mechanics dictate that as opposed to microwave frequencies, quantum coherence is preserved at room temperatures for terahertz (THz) frequencies. This makes the THz band a promising solution for room‐temperature QKD implementation in future wireless communication networks. The authors present the principles of continuous variable QKD (CV‐QKD) systems and review the latest developments in the design and analysis of CV‐QKD systems operating at microwave and THz frequencies. The authors also discuss how multiple‐input multiple‐output transmission can be incorporated into the quantum communications framework to improve the secret key rates and increase the coverage distances of the THz CV‐QKD system. Furthermore, major hardware challenges that must be surmounted to practically realise THz CV‐QKD systems are highlighted.
In the contemporary digital era, ensuring the security of sensitive data and communication is of paramount significance. Encryption methods have been widely employed to safeguard data transmission over public channels. However the exponential growth in computational power has led to concerns regarding the potential vulnerability of encryption methods. Consequently, breaking encryption poses a significant threat to data privacy. In response to these challenges, the field of quantum cryptography has emerged as a promising solution, offering a fundamentally unbreakable approach to secure communication. One of the key advancements in quantum cryptography is quantum key distribution (QKD). This secure communication mechanism relies on the principles of quantum mechanics to generate encryption keys, enabling secure information exchange between parties. This paper focuses on analysis of the quantum channel between the optical ground station (OGS) and the high-altitude platform System (HAPS). The research involves a meticulous examination and optimization of various system parameters such as performance secret key rate (SKR), electronic noise, modulation variance, and zenith angle. Remarkably, the SKR for a HAPS operating at a vertical altitude of 20 km, with a zenith angle of 20 degrees and a pulse generation rate of 500MHz, is approximately 84Mb/s and 44.5 Mb/s for homodyne and heterodyne detection, respectively. This information highlights the potential of quantum cryptography in providing secure communication channels that are resilient to cryptographic attacks.
Cyberspace has become the most popular carrier of information exchange in every corner of our life, which is beneficial for our life in almost all aspects. With the continuous development of science and technology, especially the quantum computer, cyberspace security has become the most critical problem for the Internet in near future. In this paper, we focus on analyzing characteristics of the quantum cryptography and exploring its advantages of it in the future Internet. It is worth noting that we analyze the quantum key distribution (QKD) protocol in the noise-free channel. To include real practical stimulators, there are developed various QKD Schemes for the noisy channels. Here we develop the unconditional security of quantum cryptography theoretically, which is suitable for the Internet as ever-increasing challenges are inevitable in the future. Quantum key distribution (QKD) uses individual light quanta in quantum superposition states to guarantee unconditional communication security between distant parties. In practice, the achievable distance for QKD has been limited to a few hundred kilometers, due to the channel loss of fibers or terrestrial free space that exponentially reduced the photon rate. Also experimentally it is proved that the Satellite-based QKD promises to establish a global-scale quantum network by exploiting the negligible photon loss and decoherence in the empty space. In this paper, we also give some introduction to various public-key cryptography and also touch on the various functions, advantages, and disadvantages of quantum cryptography and the need for quantum cryptography in the future as in data encoding, and digital signatures, and many more. It also covers the various securities issue of our current cryptography system. Different protocols BB84 i.e., the first QKD protocol also some other protocols, and finally the future directions of quantum cryptography followed by the conclusion of the paper.
Quantum key distribution (QKD) is a cryptographic method enabling two parties to establish a private encryption key. The range of communication of ground-based QKD is limited to an order of 100km, due to in-fibre attenuations and atmospheric losses, and the development of quantum repeaters remains technologically challenging. While trusted-node links make communication over large distances possible, satellite-QKD is required for communication over global distances. By using satellites equipped with high-quality optical links, satellite-QKD can achieve ultra-long-distance quantum communication in the 1000-km range. The significant potential of satellite-QKD for the creation of global quantum networks thus makes it a particularly interesting field of research. In this analysis, we begin with an overview of the technical parameters of performing satellite-QKD, including infrastructure and protocols. We continue with a high-level summary of advancements in satellite-QKD by analysing past, present and proposed satellite-QKD missions and initiatives around the world. We conclude by discussing the technical challenges currently faced in satellite-QKD, which can be tackled through future research in this area.