Secret Key Generation Technology Of Physical Layer Based On Wireless Channel

In recent years, as wireless communication devices deepened people’s lives, security problems caused by the openness of the wireless communication can not be ignored.Wireless channel has the nature of the reciprocity, uniqueness, fast time-varying and unpredictable, which can dynamically generate keys makes it possible to realize “one-time pad” and unconditional security.This paper extracts the channel phase information to generate the secret key in the wireless channel.It also studies the conditional probability density function of the channel phase, the consistency probabilities of the secret key, quantification of key generation and other technology.Main research works as follows:(1)Based on the wiretap channel,the expression of receiving signals on narrow-band fading channel is studied.Then information of channel estimation and capacity of key derivation is derived.After that,the probability density function of the estimated phase is given based on the actual channel phase,with the corresponding graph as well.(2)Multibit adaptive quantization phase scheme is designed.Theoretical derivation of secret key disagreement probability is given.And effect of SNR on the bit inconsistent rates is studied.Then we compare the proposed scheme with the multibit adaptive quantization amplitude scheme.Simulation results show that the scheme based on phase has higher key agreement probability and better key randomness, and is closer to the theoretical value.(3)The quantization protective band is added to the multibit adaptive quantization scheme to filter estimateded values outside protective band. Theoretical derivation of secret key disagreement probability with quantization protective band is given。Simulation results show that the protective band can effectively improve the consistency of secret key.