New Protocols For Quantum Private Query Against Joint-Measurement Attack

Quantum cryptography is a branch of cryptography based on the basic principles of quantum mechanics.Different from the classical cryptography,the security of quantum cryptography does not rely on computational complexity,but is guaranteed by the principles of physics.At present,quantum cryptography has become a research hotspot in cryptosystems.In addition to the extensive research on quantum key distribution,quantum private query is also a hot topic in recent years.The main content of this thesis is the theoretical research of quantum private query in resisting joint-measurement attack.For the problem that most QKD-based quantum private queries are difficult to resist joint-measurement attack,this thesis proposes two new two-way quantum private query protocols,and analyzes the security and performance of the proposed protocols.Secondly,the specific oblivious key generation processes overcome the shortcomings of two-way communication,such as unsatisfactory transmission distance and difficulty in resisting Trojan horse attacks.Protocol I designs a special procedure "receive?measure?re-prepare?send" for the user Alice.This process effectively prevents the dishonest Alice from saving the quantum states without conducting measurement,and performing the joint-measurement attack at the end of the protocol,thereby illegally stealing information from the database Bob.In addition,since each photon only travels from one party to the other,our protocol reduces the drawback of two-way communication so that the transmission distance between Alice and the database holder Bob is satisfactory,and the protocols can effectively resist some Trojan-horse attack.Protocol ? designs a novel checking step.The step of "Alice measurement?re-preparation?block-shifting?Bob checking" makes the protocol perform well against the joint-measurement attack and overcomes the shortcomings of two-way communication.On-the other hand,because the key is encoded on the measurement bases,the protocol ? can flexibly select multiple sets of measurement bases according to different database sizes,and adjust the protocol to achieve the optimal communication efficiency.