Application And Research Of Physical Layer Secret Key Generation Technology

Physical layer secret key generation technology is a security technology that generates keys by exploring the randomness of the wireless channel.This technology generates symmetric keys based on the channel reciprocity,and guarantees safety based on space-time randomness.This thesis studies the technology from three aspects of performance,application scenarios and research models,separately.In terms of performance,this paper proposes a highly adaptive key generation scheme based on the channel response of orthogonal frequency division multiplexing(OFDM)systems.Firstly,linear minimum mean square error(LMMSE)estimation is applied to improve the channel estimation accuracy.Moreover,interleaving is combined with preprocessing method to enhance key randomness(KR).Furthermore,a highly adaptive quantization method is proposed,including the adaption of the guard interval,the quantization level and the quantization threshold.Finally,simulation results show that the key agreement rate(KAR)and KR of this scheme are better than general schemes in the same scattering environment.In terms of application scenarios,this paper extends physical layer key generation technology to the time division duplex underwater acoustic(TDD-UWA)communication system.First of all,the main issues of key generation technology in TDD-UWA communication is analyzed.Second,a local pilot auxiliary channel sounding wait protocol is proposed to solve impaired reciprocity problems caused by the great transmission delay.At the same time,an assembly line protocol is proposed to solve the problem that the key generation rate(KGR)decreases rapidly with the increase of communication distance.In addition,the feasibility of traditional consistency enhancement techniques is discussed,and the security performance and advantages of proposed protocols are analyzed.Furthermore,a double-layer compensation centralization combined with adaptive guard interval quantization method is proposed to improve the KAR and KGR.Finally,the KAR,KGR and KR of proposed scheme are analyzed,and the adoption of proposed schemes in TDD-UWA communication system is verified to be feasible.In terms of research models,this paper explores the necessary conditions and security of the channel sounding protocol.First,the defects of the available channel sounding protocols are discussed.In addition,a non-time limited channel sounding protocol that does not depend on channel reciprocity and is not subject to communication delay constraints is proposed.Furthermore,the multi-relay scalability of this protocol is analyzed,and a relay assist extension mechanism is proposed to prevent collaborative eavesdropping.Last but not least,the above conclusions are verified by numerical simulations.