A Quantum Key Distribution (QKD)-assisted Physical Layer Security (PLS) scheme for Multiple-Input Multiple-Output (MIMO) wireless links is proposed and numerically evaluated. The framework utilizes high-rate quantum keys to generate unitary precoding matrices for channel estimation preamble encryption, alongside a constellation-based encryption methodology for the data payload. Integration of the QKD is facilitated by a practical Key Management System (KMS) that orchestrates key synchronization and ensures seamless interoperability with the QKD infrastructure. By securing both the preamble and payload portions of the transmission frame, the proposed scheme prevents unauthorized entities from acquiring critical knowledge of transceiver functionalities. Furthermore, the framework leverages high-entropy QKD-derived keys to reseed a pseudo-random number generator (PRNG), providing a symmetric-key encryption layer that enhances data confidentiality. Numerical evaluation results obtained within a simulated residential wireless environment demonstrate that the proposed architecture yields enhanced security at the cost of a minor degradation in reception performance, driven by a small noise amplification penalty and a marginal elevation in the peak-to-average power ratio (PAPR).
A Quantum Key Distribution (QKD)-assisted Physical Layer Security (PLS) scheme for Multiple-Input Multiple-Output (MIMO) wireless links is proposed and numerically evaluated. The framework utilizes high-rate quantum keys to generate unitary precoding matrices for channel estimation preamble encryption, alongside a constellation-based encryption methodology for the data payload. Integration of the QKD is facilitated by a practical Key Management System (KMS) that orchestrates key synchronization and ensures seamless interoperability with the QKD infrastructure. By securing both the preamble and payload portions of the transmission frame, the proposed scheme prevents unauthorized entities from acquiring critical knowledge of transceiver functionalities. Furthermore, the framework leverages high-entropy QKD-derived keys to reseed a pseudo-random number generator (PRNG), providing a symmetric-key encryption layer that enhances data confidentiality. Numerical evaluation results obtained within a simulated residential wireless environment demonstrate that the proposed architecture yields enhanced security at the cost of a minor degradation in reception performance, driven by a small noise amplification penalty and a marginal elevation in the peak-to-average power ratio (PAPR).
A Quantum Key Distribution (QKD) based Physical Layer Security (PLS) scheme (QKD-PLS) for optical fiber links is proposed and evaluated. In detail, a novel amplitude and phase scrambling technique for exploiting and seamlessly integrating high key rate QKD for the encryption of the modulation parameters of conventional complex modulation schemes like M-ary Quadrature Amplitude Modulation (M-QAM) and Orthogonal Frequency Division Multiplexing (OFDM) is described. The technique masks the information at the bit level and blocks unauthorized access to the higher layer encrypted bitstream. Scrambling is applied to both the preamble (pilot) and payload segments of the transmission frame, to prevent the eavesdroppers from performing vital receiver functions such as frame synchronization and channel estimation. Additionally, a practical Key Management System (KMS) which takes care of all synchronization processes is developed and introduced. Experimental transmission scenario in fiber links is also presented and depicts the efficacy of the QKD-PLS. Moreover, another advantage of QKD exploitation to the proposed solution comes from the application of kbps-rate QKD keys which feed pseudo-random number generators, to modify the broadband modulation symbols in one-time pad, therefore significantly improving data protection.
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.
In physical-layer security, secret bits are extracted from wireless channels. With the assumption of channel reciprocity, the legitimate users share the same channel which is independent of the channels between the legitimate users and the eavesdropper, leading to secure transmissions. However, practical implementation of the physical layer security faces many challenges. First, for the correlated channel such as the multiple-input and multiple-output (MIMO) channel, the security is decreased due to the correlation between the generated secret bits. Second, the nearby eavesdropper posts a security threat due to observing the same channel as the legitimate user's. Third, the eavesdroppers might try to reconstruct the wireless environments. In this paper, we propose two practical physical layer security schemes for the MIMO orthogonal frequency-division multiplexing (MIMO-OFDM) systems: the precoding matrix index (PMI)-based secret key generation with rotation matrix (MOPRO) and the channel quantization-based (MOCHA) scheme. The former utilizes PMI and rotated reference signals to prevent the eavesdroppers from learning the secret key information and the latter applies channel quantization in order to extract more secret key bits. It is shown that not only the secure communication but also the MIMO gain can be guaranteed by using the proposed schemes.
A novel Physical Layer Security (PLS) framework is conceived for enhancing the security of wireless communication systems by exploiting multi-domain polarization in Multiple-Input Multiple-Output (MIMO) systems. We design a sophisticated key generation scheme based on multi-domain polarization and the corresponding receivers. An in-depth analysis of the system’s secrecy rate is provided, demonstrating the confidentiality of our approach in the presence of eavesdroppers having strong computational capabilities. More explicitly, our simulation results and theoretical analysis corroborate the advantages of the proposed scheme in terms of its bit error rate (BER), block error rate (BLER), and maximum achievable secrecy rate. Our findings indicate that the innovative PLS framework effectively enhances the security and reliability of wireless communication systems. For example, in a4×4MIMO setup, the proposed PLS strategy exhibits an improvement of 2dB compared to conventional MIMO, systems at a BLER of2⋅10−5while the eavesdropper’s BLER reaches 1.
Physical-layer key generation (PKG) leverages the reciprocity of wireless channel to distribute a symmetric secret key between two legitimate transceivers. This paper proposes an efficient and standard-compliant PKG scheme in 802.11 MIMO-OFDM (multiple-input multiple-output, orthogonal frequency division multiplexing) networks. Firstly, we propose to extract secret keys from a novel feature referred to relative channel state information (RCSI), which can eliminate the non-reciprocity caused by transceiver mismatch and synchronization errors. Specifically, the RCSIs are derived through dividing the channel state informations (CSIs) of non-reference antennas by those of reference antennas. By setting the spatial mapping matrices of the sounding packets as permutation matrices, the reference antennas are determined implicitly without the need for information exchange. Secondly, based on the 802.11 low-density parity-check code (LDPC), we propose an adaptive information reconciliation algorithm, which is flexible to fit the various scenarios with different key lengths and bit disagreement ratios. At last, the overall PKG procedure with detailed frame format design is provided. The proposed scheme is evaluated through an 802.11ax link-level simulation. Numerical results show that the key generation rate of the proposed scheme can achieve 0.47~14Mbps for practical settings.
ABSTRACT Millimeter‐Wave (mmWave) massive Multiple Input Multiple Output (MIMO) with Orthogonal Frequency Division Multiplexing (OFDM) is a key enabler of next‐generation wireless communication, providing high spectral efficiency and improved data rates. Massive MIMO utilizes a large number of antennas at the base station to enhance spatial diversity, while OFDM mitigates inter‐symbol interference and enhances spectral efficiency. The combination of mmWave and massive MIMO with OFDM enables high‐capacity communication with reduced latency, making it ideal for 5G and beyond networks. Physical Layer Security (PLS) provides a robust alternative to traditional cryptographic techniques, leveraging information‐theoretic principles to counter advanced eavesdropping threats, including quantum computing attacks. However, conventional PLS key generation methods suffer from reduced secrecy due to the slow variation of channel characteristics. To enhance security, a deep learning‐based key generation approach is proposed using a deep graph convolutional neural network to extract virtual angle of arrival and angle of departure features. The proposed method achieves a bit agreement ratio of 0.5767 and a key generation rate of 1856.59 bits/s, significantly improving key secrecy. Secure data transmission is ensured using a hybrid deep Q‐learning with recurrent neural network framework, incorporating on‐off transmission schemes, which enhances security by achieving a secrecy capacity of 5.37 bps/Hz, maintaining a throughput of 119.55 Mbps, and a latency of 8.00 ms, ensuring scalability. Additionally, evaluations of the secrecy rate of 5.37 bps/Hz, secrecy outage probability of 10 −2 , and 95% Eavesdropper interception capability, demonstrate significant improvements over state‐of‐the‐art techniques.