Mechanism Research On High Performance Of Multimedia Continuous Variable Quantum Key Distribution

Based on the unique properties of quantum signals,people discovered the unconditional security of quantum secret communication.As a state-of-the art technology,quantum secret communication breaks the tradition of cryptography based on mathematical complexity and opens up a new mechanism of cryptography from the physical level.At present,quantum key distribution technology is the fastest-growing and remarkable effect in quantum secret communication.First of all,the zero-photon quantum catalysis(ZPQC)in the unidimensional(UD)protocol is applied to lengthen continuous-variable quantum key distribution(CVQKD)and simplify optical devices.This scheme employs the ZPQC-based operation at the transmitter to resist the extra untrusted tunnel noise,whereas avoiding the loopholes opened by the transmission of local oscillator.The unidimensional protocol practically simplifies detection in one of the quadrature modulations and the corresponding channel transmittance estimation.Then,quantum catalysis is considered to improve the discrete-modulated(DM)CVQKD.Compare with the original protocol,it enhances the performance in terms of the maximal transmission distance and security key rate.Thirdly,a DM quantum key distribution protocol with quantum scissors is proposed,which shows higher venerability with lower coordination efficiency when optimizing the original protocol.In the satellite-ground channel,this dissertation proposes an up-link CVQKD scheme based on noiseless attenuation(NA)operation,which uses ZPC to achieve noiseless attenuation of quantum signal source.This increases the maximum permissible zenith angle of the up-link system,which increases the effective communication time to exchange more information and decreases the amount of information acquired by eavesdroppers.Then two wavelength attack schemes for the turbulent atmospheric CVQKD are considered and two schemes based on the estimation of atmospheric channel parameters are described.This dissertation also demonstrates the effect of atmosphere on satellite-mediated continuous variable quantum key distribution,involving transmittance,optical fiber coupling and over-noise,and considers the effects of down-link and up-link and their differences.For seawater channel,this dissertation discusses the implementation of two kinds of wavelength attacks Gaussian modulation protocol and discrete modulation protocol,then reviews the wavelength attacks and discusses the success criteria under two different attack schemes.It is found that the success criteria are independent of Alice’s modulation variance.It is also applicable to Gaussian modulation and discrete modulation protocols.