Physical-Layer Security and Quantum Key Distribution

Ivan B. Djordjević

Θωμάς Νίκας, Eleftherios Rousas, Manolis Mylonakis +4 more

Physical Layer Security (PLS) exploits characteristics and properties of the physical layer for data encryption and supplements conventional cryptography for enhanced overall security. Most of the PLS methodologies rely on the (statistical) characteristics of the transmission channel to either generate secure encryption keys, or to exploit them together with other physical layer characteristics (i.e. advanced modulation schemes) for secure transmission. However, these approaches often lead to increased complexity and therefore become impractical for actual system implementation. Recent advancements in Quantum Key Distribution (QKD) systems allow for the utilization of ultra-secure and robust high-rate key exchange. In this work, we propose and describe practical techniques for exploiting and seamlessly integrating highrate QKD keys to encrypt modulation parameters and quantities of conventional modulation schemes like M-QAM, DMT and OFDM of communication links. Moreover, we present transmission scenarios, integrating QKD-PLS in free space optics links, together with their numerical evaluation. The main advantage of QKD exploitation to the proposed solutions comes from the seamless and transparent integration and application of high-rate keys which can either be used in their original form or feed a pseudo-random number generator, to modify the modulation properties/symbols in very high rates, such that eavesdropping and decoding of the encrypted information becomes almost impossible. Additionally, we present the architecture of a real time practical system utilizing and seamlessly integrating the QKD keys into transceiver links to form a robust and ultra-secure PLS ecosystem.

Yogesh Pandya, Ankit Soni, Anshika Gangrade +3 more

Key generation is one of the basic techniques used to realize secure channels in this digital world. This article compares both Quantum Key Distribution (QKD) and Physical Layer Key Generation (PLKG). While QKD can give information-theoretic security by invoking principles of quantum mechanics, PLKG is based on exploiting inherent randomness and reciprocity in wireless channels to extract the key. This study, through simulations, provides a comparative analysis of the security and performance aspects of QKD and PLKG against key rate, error rate, bandwidth, channel loss, and Signal-to-Noise Ratio (SNR). The results demonstrate strong trade-offs between QKD and PLKG in terms of security, practicality, and efficiency, with QKD bringing better guarantees for security but both inherently limited in terms of distance and key rate. On the other hand, PLKG is more readily deployable with higher key rates, based on computational security assumptions. This work provides practical guidelines concerning the applicability of both approaches for specific communication applications based on system requirements for communication security.

Paulo Vinícius Pereira Pinheiro, Rubens Viana Ramos

Máté Galambos, M. A. Vázquez‐Castro, László Bacsárdi

Quantum key distribution networks offer secure communication by leveraging quantum physical principles. However, their current solutions and standards are rigid, and do not incorporate the principle of cryptographic agility. In this paper we present a functional framework of agility that is applicable to hardware specific functions as well as software and we extend its applicability beyond cryptography. We explore how this framework can be applied to different layers of abstractions in a generalized quantum key distribution network. Using this framework, we construct examples of how hardware can be modified to make various components in a quantum key distribution network agile and identify general strategies to achieve agility. We explore how other physical layer security protocols beyond traditional quantum key distribution can be integrated into an agile generalized quantum key distribution network.

Norbert Lütkenhaus