Semi-quantum Secure Direct Communication Protocols Based On Cluster States And High-dimensional Quantum States

Quantum cryptography is the combination of classical cryptography and quantum information,its security relies on quantum non-cloning theorem and Heisenberg Uncertainty Principle.As an important branch of quantum cryptography,quantum secure direct communication is dedicated to transmitting the secret messages directly between legitimate participants without sharing keys in advance.Due to its remarkable advantages in real-time communication,quantum secure direct communication has been widely concerned by many researchers once put forward,and with the deepening of research,many important application types have been developed,such as mediated quantum secure direct communication and multi-party quantum secure direct communication,etc.However,since it is difficult to meet the requirement that every participants in the quantum secure direct communication have expensive quantum devices,lowering the threshold of protocol execution has become an urgent problem to be solved.To solve this problem,Boyer et al.invented the semi-quantum concept in 2007,which was soon applied to quantum secure direct communication,and semi-quantum secure direct communication came into being.However,most of the existing semi-quantum secure direct communication can only realize one-way secret message transmission between two participants,which has strong limitations.Bidirectional semi-quantum secure direct communication and multi-party semi-quantum secure direct communication break these limitations and are more in line with future development trends.In this dissertation,a bidirectional semi-quantum secure direct communication protocol and a multi-party semi-quantum secure direct communication protocol are designed and analyzed.The specific work is as follows.Based on four-particle cluster states,a multi-party semi-quantum secure direct communication protocol is designed,which includes secret message receiver Charlie with complete quantum capabilities and secret message senders Alice and Bob with only classical capabilities.The protocol enables two senders to send secret messages to the receiver simultaneously,and can be extended to a multi-party semi-quantum dialogue protocol.Furthermore,by combining quantum error correction coding,this dissertation also designs a multi-party quantum secure direct communication which can be executed in a noisy environment.Compared with the existing semi-quantum secure direct communication protocols,the presented protocols have better time efficiency and qubit efficiency.Security analysis verifies that the proposed protocols can resist some common attacks such as intercept-resend attack and measure-resend attack,etc.A bidirectional semi-quantum secure direct communication protocol with high-dimensional single-particle states is designed.The proposed protocol involves quantum party Alice and classical party Bob.Each participant can receive a secret message while send a secret message.Furthermore,the classical party Bob in the protocol does not need to possess the capabilities of generating and measuring quantum states,which greatly enhances the feasibility of the protocol.Security analysis indicates that common attack such as intercept-resend attack,measure-resend attack,tampering attack and entanglement-measure attack cannot obtain the secret messages without being discovered by legitimate participants.In addition,the proposed protocol utilizes the high-dimensional single-particle states as the carrier of secret messages transmission,which the transmission efficiency of secret messages is greatly enhanced.