International Conference on Information and Communication Technology Convergence (ICTC)

Secret Key Generation with Signal-like Noise in Polar Coded Wireless MIMO Systems

Meixiang Zhang, Xueqin Jiang, Yu‐Ting Huang

Published Oct 1, 2019• 0 citations

Abstract

Physical-layer secret key generation is a meaningful approach to enhance the security of wireless links by taking advantages of wireless channels. However eavesdroppers may obtain the secret key bits if their channels become correlated to the legitimate channels. In this paper, to increase the mismatch rate at the eavesdroppers, we propose a new secret key generation scheme for polar coded multiple-input multiple-output (MIMO) systems by applying MIMO precoding and adding signal-like noise on the transmitted signals. Furthermore, considering the channel polarization phenomenon of polar codes, we propose to adaptively send messages that are used for secret key generation over the less reliable channel-bits of eavesdroppers. In addition, we propose to add randomness to messages to ensure that eavesdroppers are unable to generate the secret key bits even when their channels are highly correlated to the legitimate channels. Simulation results demonstrate that our proposed scheme prevents eavesdroppers to generate the secret key with an extremely high probability.

DOI: 10.1109/ictc46691.2019.8939755

Related papers

Secret Key Generation With Precoding and Role Reversal in MIMO Wireless Systems

Saygın Bakşi, Dimitrie C. Popescu

Secret key generation based on channel measurements has emerged as a meaningful approach to enhance the security of wireless links. The key generation mechanism takes advantage of wireless channel reciprocity and uses the mutual information between legitimate users' channel measurements. However, the rate at which key bits are generated depends on the channel coherence time. Furthermore, eavesdroppers may obtain information to generate the secret key bits if their channels become correlated to the legitimate channels. In this paper, we propose a new approach for key generation that uses MIMO precoding and role switching by legitimate users during the key generation process in order to prevent an eavesdropper whose channel is correlated with the legitimate channel to acquire information that can be used to generate the encryption key, while also ensuring that the rate at which uncorrelated key bits are generated does not depend on the channel coherence time. The proposed approach is supported by an information theoretic analysis and is illustrated with numerical results obtained from simulations showing that, even when the legitimate and eavesdropper channels are correlated, the bit mismatch rate at the eavesdropper does not improve with increasing SNR, while that at the legitimate users improves.

IEEE Transactions on Wireless CommunicationsApr 16, 201927 citations

Secret key generation in MIMO wireless systems using precoded channel measurements

Saygın Bakşi, Dimitrie C. Popescu

Secret key generation using channel measurements has emerged as a meaningful approach to enhance the security of a wireless link at the physical layer. This paper presents a novel approach to key generation based on precoding of the MIMO channel measurements, that does not require information on the channel statistics and has the ability to generate key bits at a rate that is independent of the channel coherence time. The proposed approach is illustrated with numerical results obtained from simulations showing the probability of bit disagreement between keys generated at transmitter/receiver side and Slepian-Wolf encoding with LDPC codes is used for key reconciliation.

IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)Oct 1, 20174 citations

Precoding Adjustment Based Physical Layer Secret Key Generation for MU-MIMO Systems

Xin Biao Lu, Hua Fu

Physical layer key generation in multi-user multiple-input multiple-output (MU-MIMO) system is challenging due to the poor randomness of the equivalent channel response. The precoding matrix combines the channels from different antennas in a constructive way, resulting in a flat fading equivalent channel. In this paper, we proposes new physical layer key generation schemes based on precoding adjustment. Two strategies are proposed to enhance the randomness of the equivalent channel response at the cost of beamforming gain, which consist in adjusting random elements and adjusting the largest elements. When considering the transmission of artificial noise (AN) at the base station, random phase adjustment strategy is proposed to the precoding scheme which does not affect the beamforming gain. The signal-to-interference-plus-noise ratio of user and key generation performance are simulated. Simulation results show that adjusting the precoding elements with larger amplitudes is more efficient to increase the information entropy of the channel response. When the system is able to transmit an AN with high power ratio, random phase adjustment can help to generate secret keys with higher information entropy compared to two other strategies.

Jul 12, 20240 citations

Fast and Efficient Physical Layer Secret Key Generation over Static Wireless Channels

Jie Tang, Ruifei Wang, Huan Song +1 more

Recently, shared secret key generation from wireless channel characteristics has attracted a lot of attention due to its low computational overhead. However, in a static environment, the secret key rate is relatively lower due to the lack of channel time-variation. In this paper, we propose a lightweight and efficient PLKG scheme for static channels. Different from current schemes, in the proposed scheme, the transmitter attaches the information of the secret key into the downlink pilot signals to the legitimate receiver by the proposed secret precoding. At the receiving end, the legitimate receiver can directly observe the correct information of secret key from the public downlink pilot signals, while keeping perfect secrecy of the generated key against eavesdroppers. The key principle lies in that the information of the secret key is coded in the index of the non-activated MIMO (multiple-input-multiple-output) sub-channel. Consequently, only the legitimate receiver can accurately observe the value of the key information. For any other eavesdroppers who suffer an independent channel from the legitimate transmitter and receiver, it is proven that she cannot observe any key information from her received signals. Therefore, the key rate can be improved for the static channels by increasing the symbol rate of the pilot signals. Simulations are conducted to validate the effectiveness of the proposed scheme.

IEEE International Conference on Computer and Communications (ICCC)Dec 10, 20218 citations

Precoding Design for Key Generation in Near-Field Extremely Large-Scale MIMO Communications

Tianyu Lu, Liquan Chen, Junqing Zhang +3 more

This paper investigates an artificial randomness-based key generation scheme in near-field extremely large-scale multiple-input multiple-output (XL-MIMO) communications, aiming to overcome the limitations of static wireless chan-nels in generating secret keys. The proposed approach introduces artificial randomness via the pre coding vector, enabling legitimate users to generate secret keys while preventing eavesdropping. To maximize the secret key rate (SKR), the singular value decomposition (SVD) method is utilized to identify the legitimate subspace for generating secret keys and its orthogonal subspace to thwart eavesdropping. Additionally, a Dinkelbach method-based power allocation algorithm is designed to inject noise into both the legitimate subspace and its orthogonal subspace. Our simulation results validate the efficiency of the proposed key generation scheme, demonstrating its superiority over existing approaches.

IEEE Globecom Workshops (GC Wkshps)Dec 4, 20230 citations

Practical Physical Layer Security Schemes for MIMO-OFDM Systems Using Precoding Matrix Indices

Chih-Yao Wu, Pang-Chang Lan, Ping‐Cheng Yeh +2 more

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.

IEEE Journal on Selected Areas in CommunicationsAug 23, 201386 citations