This letter investigates the security of physical layer secret key generation in highly reconfigurable scattering environments. Based on our derived secret key capacity expression, we show that the eavesdropper's accurate knowledge of surrounding environments and propagation laws can significantly decrease the secret key capacity, i.e., the security of keys does not only rely on the channel correlation. We term this new physical layer attack as Environment Reconstruction based Attack for SEcret keys (ERASE) and provide a practical application of this attack based on a generalized 3D channel model. Finally, the impact of crucial parameters related to the channel scattering conditions is analyzed through simulation results, and useful insights for the secure and practical design of physical layer key generation are highlighted.
This letter investigates the security of physical layer secret key generation in highly reconfigurable scattering environments. Based on our derived secret key capacity expression, we show that the eavesdropper's accurate knowledge of surrounding environments and propagation laws can significantly decrease the secret key capacity, i.e., the security of keys does not only rely on the channel correlation. We term this new physical layer attack as Environment Reconstruction based Attack for SEcret keys (ERASE) and provide a practical application of this attack based on a generalized 3D channel model. Finally, the impact of crucial parameters related to the channel scattering conditions is analyzed through simulation results, and useful insights for the secure and practical design of physical layer key generation are highlighted.
Unmanned aerial vehicle (UAV) will be an essential carrier for future wireless communications due to its flexible deployment and low cost. As such, the information security of UAV communications is of paramount concern. In this paper, a novel physical layer secret key generation scheme is proposed for air-to-ground (A2G) UAV multiple-input-multiple-output (MIMO) communications, which is applicable in frequency division duplex (FDD) systems. In UAV communications, line-of-sight (LoS) propagation is a distinctive feature, which significantly weakens the performance of channel state information (CSI) based keys. Therefore, a novel channel parameter, three-dimension (3D) spatial angle, is employed to combat against a novel active eavesdropping method, which is termed as Environment Reconstruction based Attack for SEcret keys (ERASE). Compared to the existing plane-angle-based method, our scheme can efficiently utilize spatial resources and provide a higher key generation rate (KGR). The advantages of the proposed scheme are shown through both theoretical analysis and simulations.
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.
Physical layer secret key generation schemes can provide lightweight encryption for resource-constrained Internet 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 makes time-varying reflection channels superimposed on the original channels. And then, the secret key capacity of all nodes within the cell coverage area can be remarkably improved. Compared with the existing methods, the scheme is loosely coupled with the existing communication system. 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 existing user-introduced randomness schemes, the proposed scheme can maintain good performance as the number of eavesdropping nodes increases. 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.
Physical layer secret key generation schemes can provide lightweight encryption for resource-constrained Internet 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 makes time-varying reflection channels superimposed on the original channels. And then, the secret key capacity of all nodes within the cell coverage area can be remarkably improved. Compared with the existing methods, the scheme is loosely coupled with the existing communication system. 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 existing user-introduced randomness schemes, the proposed scheme can maintain good performance as the number of eavesdropping nodes increases. 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.
Key generation technique generates symmetric keys based on the temporal variation, reciprocity and spatial decorrelation of the wireless channel. Most key generation schemes, however, assume that the eavesdropping channels are independent of the main channel and neglect the influence of the eavesdroppers. In this paper, we analyze the secret key capacity taking into account the information leaked to eavesdroppers, and the security analysis shows the eavesdropping channel correlation will reduce the secret key capacity. Then we propose a security channel estimating (SCE) scheme to resist eavesdroppers and the scheme is shown to be efficient. Finally, we use the Monte Carlo simulation verifies the theoretical analysis results.
Physical layer secret key capacity is affected by such factors as additive noise, the time difference of channel sampling, terminal's moving speed, sampling period, and the number of samples, whose effects on the physical layer secret key capacity are analyzed quantitatively using the single-input single-output wireless channel over the uniform scattering environment. Specifically, a closed-form solution to the secret key capacity is derived to determine the constraints on the optimal sampling period. Analysis and simulation results reveal that the results can also be applied to the nonuniform scattering environment. Furthermore, the feasibility to utilize the physical layer secret key extraction techniques in the mobile communication systems is verified.