Research On Key Generation And Negotiation Of Physical Layer In Wireless Communications

In recent years,with the rapid development of wireless communications,people enjoy the convenience brought by the high and new technologies.At the same time,the security and privacy risks faced by the broadcast and openness of wireless media,also seriously affect people's lives,which has become the focus of scholars.Due to the arrival of the quantum era,the traditional encryption technology is easy to be broken.The wireless physical layer key technology can avoid the risk of leaks caused by the secret key distribution for the traditional encryption technology.It utilizes the time-varying and reciprocity nature of radio channel,not only to achieve "one-time pad",but also to eliminate the need for secret key distribution,which could realize unconditional security.Most of the secret key generation methods are considered only a single channel characteristic.So in the rapid changing channel,there may be some problems such as low adaptability and low initial key agreement.This paper provides new physical layer key generation method based on joint channel amplitude and phase,and studies the randomness of secret key,bit error rate,the initial secret key generation and key capacity,the main research work is as follows:(1)The physical layer secret key generation methods based on wireless channel characteristics are reviewed and their advantages and disadvantages are compared.According to the inconsistent problem of the initial generation of the key,this survey analyses the key agreement protocol in three aspects: information reconciliation,consistency authentication and privacy amplification.Some typical techniques and algorithms are summarized,and their advantages and disadvantages are compared.(2)Based on narrowband flat fading channel,a new two-dimensional wireless physical layer secret key generation method based on joint channel amplitude and phase is proposed.In this method,the estimated channel amplitude and channel phase are combined into a polar coordinate point.Simulation results show that compared with the phase secret key generation method,the proposed method has lower initial key inconsistency rate.(3)On the basis of the wiretap channel model,utilizing the concepts and properties of random variables and information entropy,the key capacity of the channel amplitude and the channel phase is derived.Based on the secret key capacity,an adaptive multi bit secret key generation scheme is designed.Simulation results show that a compromise can be made between the generation rate and the bit error rate.