Application And Research Of Wireless Physical Layer Secret Key Generation Technology

The physical layer key generation technology mainly uses the reciprocity,time variation and spatial uniqueness of the wireless channel to generate random sequences.Different from traditional encryption methods,the physical layer key generation technology does not need the key management and distribution of the third-party trusted party.Key generation can achieve one-time pad in theory,which can obtain the absolute security in Shannon's secure communication.In the era of 5G and Internet of Things,physical layer key generation technology can complement or replace traditional encryption methods,so that the technology has great prospects.This thesis focuses on the research on application scenarios of the physical layer technology.The main work and innovation are as follows:(1)The physical layer key generation technology is extended to the underwater sensor network.First,in order to solve problems of long transmission distance and impaired reciprocity problems caused by the large communication delay in the underwater sensor network,a pilot assisted relay detection protocol is proposed.Second,in order to further strengthen the ability of key generation scheme to resist neighbor eavesdropping,a pilot assisted relay secret protocol is proposed.This protocol not only ensures the security of the key generation scheme,but also improves the key agreement rate(KAR)and the key generation rate(KGR).Third,in order to reduce the influence of signal attenuation and noise,the pilot assisted relay amplification protocol and the pilot assisted mean amplification protocol are proposed,and the KAR and KGR of key generation technology are further optimized.Finally,the KAR,KGR and key randomness(KR)of proposed schemes are analyzed by simulation results,and the feasibility of proposed schemes in the underwater sensor network is verified.(2)Aiming at the current existing key generation schemes that are mostly based on passive eavesdropping,and do not consider the situation of active attacks of eavesdroppers,a physical layer key generation scheme based on active eavesdropping is proposed.First,this thesis constructs a system model of active eavesdropping.Second,to address the problem of active eavesdroppers interfering with the transmission of information by legitimate users,the public pilot detection protocol based on least mean square(LMS)and the public pilot detection protocol based on discrete cosine transform least mean square(DCT-LMS)are proposed.While proposed protocols reduce influence of interference signals,they also significantly improve KAR.Then,in view of the problem that too many bits are discarded in the quantization preprocessing scheme,which leads to serious damage to KGR,an improved scheme is proposed.The principle is to perform modulo two addition operation on initial key sequences of both communication parties,and then the sender and receiver delete wrong bits according to the calculation result.Compared with the original scheme,while the improved scheme improves KAR,KGR is increased to 2-4 times.Finally,the whole scheme of physical layer key generation technology based on active eavesdropping is proposed,and the simulation and performance analysis of the scheme are carried out to verify the effectiveness of proposed scheme.