Research On Key Technologies Of Continuous-variable Quantum Secret Sharing

Quantum secret sharing(QSS)is an important application in quantum cryptography,it uses the basic principles of quantum mechanics to encode the secret(or secret key)information in the quantum state,so as to ensure the unconditional security of secret sharing.Continuous-variable quantum secret sharing(CV-QSS)is one of the main research directions of QSS.With the development of research on CV-QSS,its practicability has become the focus of research,how to improve the actual safety of CV-QSS system has become a key problem in the practical research.On the one hand,from the perspective of the detector,the detector may have some imperfections and be attacked by the eavesdropper.On the other hand,from the perspective of device production,quantum devices and classical devices provided by manufacturers cannot be always trusted.As a result,eavesdroppers may carry out memory attack on untrusted quantum devices,or Trojan horse attacks on untrusted classical devices,which also poses a great threat to the security of CV-QSS.In this paper,we propose two key technologies to solve the above problems,which is described as follows:1.A CV-MDI QSS scheme using prepare-and-measure(PM)method is proposed,in which quantum states from the dealer and players are measured by an untrusted third party,which can resist all the attacks carried out on detectors.Instead of preparing entanglement states,the scheme uses coherent states,which makes it more practical.Besides,the system can be extended to a large number of players,so it is more suitable for the needs of the actual communication scenarios.We give the schematic setup of the proposed and introduce the steps in detail,then we analyze and prove the security of the scheme,and show the influence of different parameters on the performance of the scheme by simulation.2.Redundant devices are used to improve the security of practical CV-QSS system in the presence of untrusted devices.By combining with redundant devices together with privacy amplification and VSS,we can prevent eavesdroppers from getting any information about the secret key from untrusted quantum and classical devices.Then,we combine the two schemes to ensure the security of CV-QSS in the presence of both untrusted quantum and classical devices without affecting the security rate.Finally,we analyze the security of the redundant quantum devices scheme and redundant classical devices scheme respectively.