Intelligent Reflecting Surface-Assisted Wireless Key Generation for Low-Entropy Environments

Staat, Paul; Elders–Boll, H.; Heinrichs, Markus; Kronberger, Rainer; Zenger, Christian; Paar, Christof

doi:10.1109/pimrc50174.2021.9569556

Cited by 39 publications

(36 citation statements)

References 15 publications

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“…In static environments, the limited randomness found in the direct channel renders key generation challenging, while RISinduced channel variations can now provide the basis for PKG. Thus, with the help of RIS in PKG, the entropy of the secret key can be enhanced [4,6].…”

Section: A Case I: Static Environmentsmentioning

confidence: 99%

“…To further boost the rate, artificial randomness (AR) was introduced to form a fast-changing virtual channel that is a product of the physical channel and local AR at transceivers [2]. However, the AR-aided PKG approach needs to modify the pilot signal, which is challenging to be implemented on commercial off-the-shelf (COTS) devices, e.g., ZigBee [1], Wi-Fi [4]. These vivid examples highlight that PKG still faces challenges and thus there is a strong need to facilitate PKG in the respective scenarios.…”

Section: Introductionmentioning

confidence: 99%

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Reconfigurable Intelligent Surface for Physical Layer Key Generation: Constructive or Destructive?

Li¹,

Hu²,

Staat³

et al. 2021

Preprint

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Physical layer key generation (PKG) is a promising means to provide on-the-fly shared secret keys by exploiting the intrinsic randomness of the radio channel. However, the performance of PKG is highly dependent on the propagation environments. Due to its feature of controlling the wireless environment, reconfigurable intelligent surface (RIS) is appealing to be applied in PKG. In this paper, in contrast to the existing literature, we investigate both the constructive and destructive effects of RIS on the PKG scheme. For the constructive aspect, we have identified static and wave-blockage environments as two RIS-empowered-PKG applications in future wireless systems. In particular, our experimental results in a static environment showed that RIS can enhance the entropy of the secret key, achieving a key generation rate (KGR) of 97.39 bit/s with a bit disagreement rate (BDR) of 0.083. In multi-user systems where some remote users are in worse channel conditions, the proposed RIS-assisted PKG algorithm improves the sum secret key rate by more than 2 dB, compared to the literature. Furthermore, we point out that RIS could be utilized by an attacker to perform new jamming and leakage attacks and give countermeasures, respectively. Finally, we outline future research directions for PKG systems in light of the RIS.

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Section: A Case I: Static Environmentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reconfigurable Intelligent Surface for Physical Layer Key Generation: Constructive or Destructive?

Li¹,

Hu²,

Staat³

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Through a comprehensive review of existing literatures, most RIS aided SKG schemes can be classified into the following two categories: 1) Channel Enhancement method [10]- [12]; 2)Channel Randomization method. [13] [14]. The common idea behind the methods in the former category is the reflection shifts at the RIS are designed with statistical channel information to enhance the correlation between legitimate uplink and downlink channels while reduce their correlation with eavesdropping channels, and then key disagreement rate can be improved.…”

Section: Introductionmentioning

confidence: 99%

“…In [13], a physical layer key generation architecture based on a time-dependent randomization of the RIS configuration is proposed. Furthermore, a functional proof-of-concept system based on a lowcost RIS prototype and commodity MIMO radio transceivers is implemented which verifies the key rate can be improved [14]. However, the above research mainly considers the simple single-user case.…”

Section: Introductionmentioning

confidence: 99%

RIS aided Physical Layer Key Generation of IoT network in Static Environments

Yang¹,

Ji²,

Huang³

et al. 2022

Preprint

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Physical layer secret key generation schemes can provide lightweight encryption for resource constrained Inter?net of Things (IoT) devices. However, many IoT devices are stationary and the environment is usually static, which leads to ultra-low/zero secret key rates. To circumvent this problem, a novel secret key generation scheme based on Reconfigurable Intelligent Surface (RIS) is proposed for Multiple-Input Single?Output IoT communications. The RIS is introduced into the network, and the phase shifts at RIS are tuned randomly in each frame, which superimpose time-varying reflection channels on the orginal channels. And then the secret key capacity of all nodes within the cell coverage area can be remarkably improved. The closed-form expressions of secret key capacity taking into account eavesdropping are first derived for the case studies of independent and correlated channels. We can conclude that sharing the same phase shifts randomness will not bring key information leakage. Compared with three benchmark schemes, the proposed scheme can both maintain good performance whenever eavesdropping nodes exist. Further, the impact of parameters, such as the number of reflecting units, the transmit antennas and the Rician factor, on secret key performance are analyzed respectively, which can offer guidelines for system design. Finally, simulation results verify the theoretical analysis.

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“…Inspired by this, there are several studies on the design of RIS-assisted PKG systems. For example, in static environments, a RISinduced randomness method was proposed in [2] and the experiments in [3] demonstrated its effectiveness. In addition, the authors of [1], [4], [5] investigated the optimization of RIS beamforming in dynamic environments to further improve the key generation rate (KGR).…”

Section: Introductionmentioning

confidence: 99%

Joint Transmit and Reflective Beamforming for RIS-assisted Secret Key Generation

Hu¹,

Li²,

Xing-san³

et al. 2022

Preprint

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Reconfigurable intelligent surface (RIS) is a promising technique to enhance the performance of physical-layer key generation (PKG) due to its ability to smartly customize the radio environments. Existing RIS-assisted PKG methods are mainly based on the idealistic assumption of an independent and identically distributed (i.i.d.) channel model at both the transmitter and the RIS. However, the i.i.d. model is inaccurate for a typical RIS in an isotropic scattering environment. Also, neglecting the existence of channel spatial correlation would degrade the PKG performance. In this paper, we establish a general spatially correlated channel model in multi-antenna systems and propose a new PKG framework based on the transmit and the reflective beamforming at the base station (BS) and the RIS. Specifically, we derive a closed-form expression for characterizing the key generation rate (KGR) and obtain a globally optimal solution of the beamformers to maximize the KGR. Furthermore, we analyze the KGR performance difference between the one adopting the assumption of the i.i.d. model and that of the spatially correlated model. It is found that the beamforming designed for the correlated model outperforms that for the i.i.d. model while the KGR gain increases with the channel correlation. Simulation results show that compared to existing methods based on the i.i.d. fading model, our proposed method achieves about 5 dB performance gain when the BS antenna correlation ρ is 0.3 and the RIS element spacing is half of the wavelength.

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Intelligent Reflecting Surface-Assisted Wireless Key Generation for Low-Entropy Environments

Cited by 39 publications

References 15 publications

Reconfigurable Intelligent Surface for Physical Layer Key Generation: Constructive or Destructive?

Reconfigurable Intelligent Surface for Physical Layer Key Generation: Constructive or Destructive?

RIS aided Physical Layer Key Generation of IoT network in Static Environments

Joint Transmit and Reflective Beamforming for RIS-assisted Secret Key Generation

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