Design And Analysis Of Quantum Cryptographic Protocols With Single Photon

Quantum cryptography,a new cryptographic technology developed in the past 30 years,is the product of the combination of classical cryptography and quantum mechanics.Unlike the classical cryptography,quantum cryptography security does not depend on the complexity of calculation,but on the fundamental laws of quantum mechanics.The fundamental laws of quantum mechanics make quantum cryptography can provide with unconditional security and the ability of detecting eavesdropping.It gives quantum cryptography incomparable advantages over classical cryptography.Since the birth of quantum cryptography in 1984,a large number of quantum cryptography protocols had been proposed.These protocols enriched the research of quantum cryptography and promoted the development of quantum cryptography.Most of the existing quantum cryptographic protocols were based on entangled states,and few quantum cryptographic protocols used single photon.However,in practical applications,single photon is considered to be the most ideal quantum signal source.Although the single photon could be disturbed in the environment,compared with the cost of restraining the quantum decoherence of the environment on entangled quantum system,the cost of restraining environment on single photon interference is lower and technically easier to achieve.And the measurement of single photon is simpler and cheaper.Compared to entanglement protocols,single-photon protocols have a more prominent advantage in terms of scalability and feasibility.Therefore,this paper focuses on the design and analysis of quantum cryptography protocol with single photon.The main contents include quantum secret sharing and quantum direct communication.The specific research results are as follows:(1)Because the existing quantum secret sharing protocols are only based on high-dimensional or two-dimensional quantum systems,there is no effective scheme for the secret sharing of quantum systems with different dimensions for distributors and participants.Therefore,a quantum secret sharing protocol based on Huffman tree and orbital angular momentum cascade sorting network is proposed.Firstly,the corresponding Huffman tree is constructed based on the original secret,and then the orbital angular momentum cascade sorting network with the same structure as Huffman tree is constructed to complete the secret sharing from the high-dimensional quantum system to the two-dimensional quantum system.Compared with other single photon quantum secret sharing protocols,this protocol has advantages in quantum bit efficiency and photon utilization.Through security analysis,the protocol had high security.(2)To solve the problems of low photon utilization and qubit efficiency and high cost of dynamic change of participants in existing quantum secret sharing protocols,a dynamic quantum secret sharing protocol based on fountain code is proposed.The position of the decoy particles and the measurement base information are shared with each participant in advance using the fountain code.Then,the share of the smaller key pieces is iteratively put into the share of the largest key piece,and the share of the largest key piece is expressed and transmitted by the corresponding photon sequence.At the same time,decoy photons are inserted into the photon sequence to ensure the security of communication.Iterative coding reduces the number of photons needed and improves the efficiency of quantum bits.In addition,it is not necessary to redistribute the original participant's sub-key share when the participant changes dynamically,which greatly saves the additional cost caused by the participant's dynamic changes.The protocol can be implemented using the same physical device as BB84 protocol.Security analysis shows that the protocol has high security.Efficiency analysis shows that the protocol has high qubit efficiency.(3)In order to improve the photon utilization and communication efficiency of quantum direct communication,a secure and feasible deterministic secure quantum communication protocol based on arithmetic coding is proposed.Firstly,the fountain code is used to share a small amount of classical information in advance to complete the sharing of measurement base and decoding information.Then the secret information is coded by simplified arithmetic coding and the corresponding single photon sequence is prepared to transmit the secret information.Arithmetic coding makes it unnecessary to divide eavesdropping detection and confidential information transmission into two steps,which improves the efficiency of protocol communication.At the same time,the arithmetic coding characteristics make it unnecessary to discard the photons used for eavesdropping detection,which improves the photon utilization rate.The protocol can be implemented using the same physical devices as BB84 protocol.The security analysis shows that the protocol has high security.In this paper,three quantum cryptographic protocols were proposed based on single photons using several special codes.The combination of Huffman code or fountain code with quantum secret sharing increased the photon utilization of two quantum secret sharing protocols and greatly saves the cost of both protocols.The combination of fountain code and arithmetic coding with deterministic secure quantum communication not only overcame the problems of existing protocols,but also improved the security of the protocol.The proposed three protocols could be implemented by using existing technologies,so the three protocols could provide reference for the practical quantum cryptographic protocol research.