Research On Physical Layer Key Generation Scheme Against Active Attack

Due to the broadcast nature of wireless networks and the rapid development of computing performance of portable computers,symmetric key encryption systems have is easy to being cracked.Researchers have proposed the physical layer key generation scheme to solve this problem,which generate symmetry key from the wireless fading channel between two wireless devices by exploiting channel randomness and reciprocity.Current efforts have focused mainly on the security issue and design of the physical layer key generation scheme under passive attacks,and there is insufficient research on the physical layer key generation scheme under active attacks.In this article,we discussed a variety of active attack solutions and countermeasures,the main work is as follows:(1)The development process of the physical layer high key generation method is reviewed,and the impact of active attacks on the traditional physical layer key generation method is analyzed.The traditional physical layer key generation method has a low key agreement rate under interference attacks,and some keys may be cracked under channel control attacks and signal injection attacks.(2)Aiming at interference attacks,this paper proposes time-domain extension signals for channel detection,and uses the uncorrelated characteristics of time-domain extension signals and interfering signals.At the receiving end,channel characteristics are extracted by calculating the correlation between the transmission sequence and the reception sequence.The correlation coefficients of the channel feature sequences extracted by both sides of the key generation are deduced,which proves that the new key generation method can greatly improve the similarity of the channel detection sequence,and gives the optimal time-domain extended signal length and Doppler The relationship between frequency shifts.The simulation results show that even under high-intensity interference attacks,the new method can guarantee a good key consistency rate.(3)Aiming at the problem of channel characteristic measurement value pollution caused by signal injection attacks and channel control attacks,we propose a method of randomizing channel detection signal coefficients and generating a combined channel detection sequence at the receiver.Aiming at the problem of non-negative amplitude,a method of judging positive and negative using phase information is proposed to meet the requirement that the mean value of random channel sounding coefficient is 0.The security of the new method under signal injection attack and channel control attack is analyzed.Simulation results show that the new method can effectively prevent the generated key from being cracked.