Research On Secret Key Generation Utilizing The Channel Characteristics

In recent years,Wireless communication technology is in rapid development while secure issues has been bottlenecks for improvements.Wireless channel openness makes this kind of communication is faced with a more severe security threat compared with wired communication.The security of the traditional security scheme is based on the complexity of the algorithm,mainly related with randomness and confidentiality of keys depends on the randomness and confidentiality of the key.To enhance the security,Traditional strategies considered applying encryption algorithms with more complexity,but system scalability would be limited though,but this will continue to increase the complexity of the implementation of the algorithm is not conducive to the development of wireless communications equipment towards the trend of miniaturization.The Physical layer security technology has broken through the traditional security solution,which uses the natural advantage of randomness of physical channel to generate the key,and it would improve efficiency of key generation obviously.But also getting closer to Shannon's “One-time pad "confidentiality program,so as to effectively improve the safety performance of security programs.So the physical layer of security technology since the date of the proposed has attracted wide attention from domestic and foreign scholars.In the physical layer security technology,the key generation technology based on the channel feature is one of the most critical technologies.This thesis mainly focus on the issues in followings.(1)This thesis finds that there are three main shortcomings in the existing scheme: first,there is no better key generation scheme to resist such attacks when active attackers implement interference channel attacks.Second,shortages of optimal feature extraction algorithm for UWB system are under estimation.Third,in the key negotiation stage,most of the existing schemes only consider the problem of key consistency,while ignoring the initial key leakage problem in the key negotiation process.(2)In order to solve the issues listed in(1),this thesis studies the key generation scheme based on random detection signal.This scheme changes the fixed detection signal in the existing generation scheme to the random detection signal and convoluted with the channel impulse function to obtain the new feature extraction signal.The key generated by this scheme not only contains the randomness of the channel,but also the randomness of the random signal,so Channel active interference attack would be resisted in a better way.(3)For the second defect,this thesis proposes a key generation scheme based on multipath delay optimal extraction algorithm.The principle of this algorithm is implementing a quick sort in multipath latency received by quickly sort the multipath latency received by the receiving end according to the size of the correlation coefficient,and select the largest value of the correlation as the channel feature to extract.The key generation scheme based on this algorithm can greatly improve the consistency of the initial security key,thus greatly reducing the overhead of key negotiation.(4)In view of the third defect,this thesis studies the key generation scheme based on confusion and RS code negotiation.The principle of this scheme is to confuse the key that needs to be transmitted in the negotiation stage,Meanwhile,RS code is implemented to correct this scheme not only ensures the consistency of the two ends of the key,but also reduces the risk of key leakage during transmission.(5)In this thesis,we study the new scheme of combining the above three improved algorithms,and give the simulation analysis.