Research On Quantum Private Comparison

Quantum cryptography is the synthesis of quantum mechanics with the art of code-making(cryptography),which is the most remarkable application in quantum informa-tion.With the rapid development of people's ability of computation,especially the presentation of some parallel quantum algorithm,the security of most classical cryp-tography which bases on computational complexity assumptions is severely challenged.The advantages of quantum cryptography has make it became an important branch of modern cryptography,and is likely to develop into an important force for the next generation of technologies in cryptography.As an important direction of researches on quantum cryptography,the quantum private comparison(QPC)has been the attention of many scholars and has produced a wealth of research results.The contributions of this dissertation are mainly on the design and analysis of QPC protocols,including design methods,attack strategies and security analysis.The details are as follows:With respect to the design of two-party QPC protocol,we propose two QPC proto-cols based on the highly entangled six-qubit genuine state and the maximally entangled five-qubit state,respectively.Two QPC protocols both employ single particle measure-ments and Bell-basis measurements,which are easy to implement in experiment;Two QPC protocols needs neither unitary operations nor quantum entanglement swapping technology,both of which may consume expensive quantum devices;In two QPC pro-tocols,a semi-honest third party is assumed,the QKD method and the decoy photons technology are adopted to guarantee security so as to reduce the consumption of quan-tum resources.Since one-step quantum transmission is adopted in two QPC protocols,they are free from Trojan horse attacks.With respect to the design of multi-party quantum private comparison(MQPC)protocol.we propose a MQPC protocol based on entanglement swapping of d-dimen-sional cat states and d-dimensional Bell states.The participants who want to compare the equality of their information employ unitary operations to encode their private infor-mation.With the help of a semi-honest third party,they can complete the comparison with one execution of the protocol.The protocol employ the properties of entanglement swapping of d-dimensional cat states and d-dimensional Bell states for security,there is no need to encrypt the information with additional generated keys,which reduces the consumption of quantum resources.