Wireless Channel-based Secret Key Generation (WC-SKG) offers a promising alternative for wireless communication security, yet suffers from an extremely low key generation rate (KGR) in quasi-static environments (e.g., indoor Internet of Things), where key refresh cycles can extend for hours, creating a security vulnerability. Reconfigurable Intelligent Surfaces (RIS) can boost KGR by introducing artificial randomness, yet existing schemes only randomize the RIS phase shifts without using environmental priors, failing to maximize the KGR and meet the communication signal-to-noise ratio (SNR) requirement, causing service outages. To overcome these limitations, we propose the RIS-assisted Integrated Communication and WC-SKG (RICK) scheme. First, we treat the RIS-adjusted channel as a designable random variable and derive its optimal probability density function (PDF) using a novel geometric-algebraic framework to maximize the KGR under the communication SNR constraint. Second, we design a constrained-clustering-based quantization region division scheme tailored to this optimal non-uniform PDF, guaranteeing uniformly distributed secret keys. Simulation results show RICK achieves a KGR approximately 3.5-5 times higher than the state-of-the-art scheme while saving at least 20 dB of transmit power for the same KGR, confirming its effectiveness in quasi-static scenarios.

This paper investigates the simultaneously transmitting and reflecting reconfigurable surface (STAR-RIS) assisted physical layer key generation (PKG) for multiuser networks. We propose a novel STAR-RIS-assisted PKG protocol and formulate a sum secret key rate maximization problem by jointly optimizing the active and passive beamforming. To address the non-convex problem, a block coordinate descent (BCD) algorithm is developed, using both semidefinite relaxation (SDR) and successive convex approximation (SCA) methods to optimize active and passive precoding alternately. Simulation results demonstrate the key generation performance of the proposed algorithm outperforms schemes that STAR-RISs using the random configuration and conventional reflecting/transmitting-only RISs.

Abstract Confidentiality and authentication are two important security properties of wireless communication. There are currently two types of research in wireless communication security: one is based on cryptography, which can be too complicated for some wireless systems; the other is based on physical layer characteristics, which has some security problems and cannot work as well as the cryptography‐based method. In this paper, a lightweight encryption and message authentication framework for wireless communication is proposed. The proposed framework has lower complexity than the cryptography‐based method and works more securely and efficiently than the classical physical layer method. For the encryption, a physical layer offered chain key (PHYLOCK) structure is proposed to generate one‐time keys, which are then XOR‐ed with the plaintext to generate the ciphertext. A security analysis of PHYLOCK is performed and it is proved that it has better security features than the traditional physical layer key generation. For the message authentication, three types of PHYLOCK‐CRC‐based message authentication schemes are developed whose generator polynomial is determined by one‐time keys generated by PHYLOCK. PHYLOCK‐CRC‐based message authentication detects not only random errors introduced by noises but also malicious attacks. The error‐detecting and anti‐attack capabilities are analyzed mathematically. Compared to the standard CRC, PHYLOCK‐CRC‐based message authentication has a decline in error correction capability but is enhanced with cryptographic security features. Monte‐Carlo simulations are provided to evaluate the proposed scheme.

Due to the channel estimation error, most of the physical layer secret key generation schemes need information reconciliation to correct error key bits, resulting in reduced efficiency. To solve the problem, this work proposes a novel secure communication scheme based on a equivalent interference channel. Different keys generated from imperfect channel state information are directly applied to signal scrambling and descrambling, which is equivalent to the process of a signal passing through an interference channel. Legitimate communication parties can reduce interference with the help of similar keys and channel coding without sending additional signals, while the eavesdropper channel is deteriorated due to the spatial decorrelation. For this kind of schemes, we first establish a discrete memoryless broadcast channel model to derive the expressions of bit error rate (BER), channel capacity, and security capacity for performance analysis. Simulation results verify the derivations that the proposed scheme achieves secure communication with a correlated eavesdropping channel and has a higher upper bound of transmission rate. Furthermore, we design a new metric to evaluate the efficiency and the result shows that the proposed scheme has superior performance on error reconciliation efficiency, despite its slight increase in BER.