Abstract This paper presents the feasibility study of deploying quantum key distribution (QKD) from high altitude platforms (HAPs), as a way of securing future communications applications and services. The paper provides a thorough review of the state of the art HAP technologies and summarises the benefits that HAPs can bring to the QKD services. A detailed link budget analysis is presented in the paper to evaluate the feasibility of delivering QKD from stratospheric HAPs flying at 20 km altitude. The results show a generous link budget under most operating conditions which brings the possibility of using diverged beams, thereby simplifying the pointing, acquisition and tracking of the optical system on the HAPs and ground, potentially widening the range of future use cases where QKD could be a viable solution.
Abstract This paper presents the feasibility study of deploying quantum key distribution (QKD) from high altitude platforms (HAPs), as a way of securing future communications applications and services. The paper provides a thorough review of the state of the art HAP technologies and summarises the benefits that HAPs can bring to the QKD services. A detailed link budget analysis is presented in the paper to evaluate the feasibility of delivering QKD from stratospheric HAPs flying at 20 km altitude. The results show a generous link budget under most operating conditions which brings the possibility of using diverged beams, thereby simplifying the pointing, acquisition and tracking of the optical system on the HAPs and ground, potentially widening the range of future use cases where QKD could be a viable solution.
This paper presents the feasibility study of deploying Quantum Key Distribution (QKD) from High Altitude Platforms (HAPs), as a way of securing future communications applications and services. The paper provides a thorough review of the state of the art HAP technologies and summarises the benefits that HAPs can bring to the QKD services. A detailed link budget analysis is presented in the paper to evaluate the feasibility of delivering QKD from stratospheric HAPs flying at 20 km altitude. The results show a generous link budget under most operating conditions which brings the possibility of using diverged beams, thereby simplifying the Pointing, Acquisition and Tracking (PAT) of the optical system on the HAPs and ground, potentially widening the range of future use cases where QKD could be a viable solution.
Quantum key distribution (QKD) is one of the most mature quantum technologies and can provide quantum-safe security in future communication networks. Since QKD in fiber is limited to a range of few hundred kilometers, one approach to bridge continental scale distances may be the use of high altitude pseudo satellites (HAPS) as mobile trusted nodes in the stratosphere. In parallel, free-space laser communication for high rate data transmission has been a subject of research and development for several decades and its commercialization is progressing rapidly. Important synergies exist between classical free-space communication and QKD systems since the quantum states are often implemented using the same degrees of freedom such as polarization or field amplitude and phase. These synergies can be used to benefit from the progress in classical free-space laser communication in QKD applications. In this paper, the use case of QKD in a stratospheric environment is described wherein HAPS may serve as relay station of secret keys and encrypted data. The mission scenario and HAPS capabilities are analyzed to derive special requirements on the stratospheric laser terminal, the link geometry and the ground segment with respect to a feasibility demonstration. To obtain a flexible and compatible system, discrete variable and continuous variable QKD protocols are considered to be implemented side by side in the HAPS payload. Depending on the system parameters, it can be beneficial to use the one or the other kind of protocol. Thus, a direct comparison of both in one and the same system is of scientific interest. Each of the protocols has particular requirements on coupling efficiency and implementation. Link budget calculations are performed to analyze possible distances, key rates and data transmission rates for the different schemes. In case of the QKD system, the mean coupling efficiency is of main interest, i.e. signal fluctuations arising from atmospheric turbulence must be taken into account in the security proof, but the buffered key generation relaxes real-time requirements. This is different to classical communications, where the corresponding fading loss must be assessed. A system architecture is presented that comprises the optical aircraft terminal, the optical ground terminal and the most important subsystems that enable implementation of the considered QKD protocols. The aircraft terminal is interfaced with the dedicated quantum transmitter module (Alice) and the ground station with the dedicated quantum receiver module (Bob). The optical interfaces are SMF couplings which put high requirements on the receiving optics, in particular the need for wave-front correction with adaptive optics. The findings of the system study are reviewed and necessary next steps pointed out.
The encryption process is essential for ensuring data protection and privacy. However, breaking the encrypted data becomes feasible as computational power grows exponentially. This leads to insecure data transmission over a public channel. Quantum key distribution is a secure communication mechanism that allows shared parties to exchange encryption keys periodically. Furthermore, it has the ability to detect eavesdropping since the error level becomes higher when she attempts to access the communication channel. This paper studies and analysis the performance of the uplink quantum channel between the ground station and the high-altitude platform system (HAPS). In order to achieve optimal performance, the system parameters, such as modulation variance, receiver aperture, and zenith angle influence, are tuned with consideration to the effects of weather conditions and beam wandering. For a HAP at vertical altitude 20 km and with 20° zenith angle and 100 MHz pulse generation rate, a raw key rate of 57 Mb/s and 63 Mb/s is estimated for homodyne and heterodyne detection schemes, respectively.
ABSTRACT Quantum key distribution (QKD) leverages the laws of quantum mechanics to enable the secure transfer of information and is the only known method of key exchange capable of providing verifiable security. While commercial optical fibre based QKD links are available, there are presently no free space based commercial solutions. Furthermore, QKD on airborne platforms has only been experimentally verified at low altitudes and at low speeds. We first survey the academic literature to identify gaps in research and establish a foundation for our own study. Subsequently, this study utilises computational modelling to find that continuous variable (CV) QKD is feasible for high‐speed airborne platforms and can provide sufficient data rates (> 100 Mb/s without multiplexing) at suitable ranges (≈15 km with full wavefront correction) for typical supersonic aircraft use cases. The implementation of such a system is economically viable as it can utilise relatively low‐cost standard devices developed by the telecommunications industry, as opposed to the specialised equipment typically required for discrete variable (DV) QKD protocols. Our results highlight how the current capabilities of such devices impose limits on the performance (data rates and ranges) of airborne QKD systems.
Abstract 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 500 MHz, is approximately 84 Mb/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.
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.