Theoretical Study On Mediated Semi-Quantum Secret Sharing

Quantum secret sharing is an important part of quantum cryptography,which can effectively manage the keys in quantum secret communication.Unlike quantum secret sharing,semiquantum secret sharing allows one participant with full quantum power to share the key with N participants with partial quantum power.However,quantum computers are too expensive to require a full quantum computer for the average user now.The introduction of quantum third party into semi-quantum secret sharing can solve the problem that quantum computing devices are difficult to obtain in practice,and it is easier to realize technically.In this thesis,we study the arbitration half quantum secret sharing and design two kinds of half quantum secret sharing protocols: one is to complete the half quantum secret sharing process when only the third party has limited quantum capacity and the other participants are classical parties.The other is the quantum secret sharing protocol in which the distributor only needs limited quantum capacity to complete the authentication when the third party provides quantum capability.The specific content is as follows:(1)Semi-quantum secret sharing(SQSS)mainly studies how to achieve secure sharing of confidential information among legal participants when some participants only have limited quantum capabilities.In this thesis,we propose three new arbitrated semi-quantum secret sharing schemes based on the single-particle,Bell and GHZ states,respectively.These protocols allow multiple classical actors to share keys with the help of third parties,where both classical actors and third parties have limited quantum capabilities.These protocols have higher security,use fewer quantum resources,and are easier to implement.The lightweight quantum-secret sharing scheme has a wide application prospect in the future cloud quantum scenarios because it reduces the quantum device requirements of participants.(2)Most of the existing half-quantum cryptography sharing schemes do not consider the problem of identity authentication,and there is the possibility of man-in-the-middle attack.To solve this problem,we propose two new authentication-based arbitrated half quantum secret sharing schemes based on GHZ states.Before secret sharing,the dispenser uses the entanglement property of GHZ state to authenticate the participants and ensure the honesty of the participants.Thereafter,the semi-quantum communication protocol realizes the secure key sharing with the help of the quantum third party.Our protocol not only guarantees the security of the protocol,but also saves quantum resources.