Research On The Security Of Continuous Variable Quantum Key Distribution Based On Atmospheric Channel

Free space quantum key distribution is a hot spot in quantum communication research,which plays a vital role in the construction of a global quantum communication network.It can safely and accurately transmit secret key to any corner of the earth regardless of geographic location.Free space quantum communication covers a wide range of fields,including ground-ground quantum communication,ground-satellite quantum communication,satellite-satellite quantum communication,maritime quantum communication,underwater quantum communication and so on.However,most types of free space quantum communication signals must pass through the atmospheric channel,which means that it is inevitable to consider the impact of atmospheric environmental factors on quantum signals.Therefore,researching the technology of quantum key distribution based on the atmospheric channel has a significant influence for building the current quantum communication network system and expanding other types of quantum key distribution systems.In this paper,a series of research are carried out on the security of atmospheric continuous variable quantum key distribution,and the main research contents are as follows:(1)From the defender’s point of view,we propose a scheme to improve the performance of atmospheric continuous variable quantum key distribution with an untrusted source.In this scheme,the entanglement source is moved to an untrusted atmospheric channel,which breaks the credibility condition that the entanglement source is protected by the legitimate party.Under the circumstances,the influence of the entanglement source location on the system performance is analyzed,and we find that the system performance is seriously affected,especially when the untrusted source is placed at the middle of channel.So,a non-Gaussian operation(photon subtraction operation)is introduced to improve the performance of system by optimizing the parameters of photon subtraction operation.(2)From the attacker’s point of view,we propose a quantum hijacking attack scheme for atmosphere continuous variables quantum key distribution based on statistical analysis.In the atmospheric channel,the transmitted gaussian state may degrade to a non-gaussian state due to the environmental factors,which could be a potential security vulnerability.Therefore,we propose a statistical analysis model to identify the distribution of quantum state in atmospheric channel,and then combine the entanglement distillation operation to launch an attack.This attack can bias the estimation of parameters between Alice and Bob,thus causing Alice and Bob to overestimate their security bounds.Compared with the existing schemes,our statistical analysis model does not need training,and only needs a small amount of data to obtain higher recognition accuracy,which indicates that our scheme is more feasible in actual atmospheric channel attacks.