Design And Analysis Of Quantum Secure Multi-Party Computation Protocols In Non-Ideal Settings

Quantum secure multi-party computation (QSMPC) performs calculations as using the laws of physic to protect private information. It allows higher security than classical secure multi-party computation which is based on the difficulty of solving mathematical problems. But in its practical applications, quantum secure multi-party computations have met a lot of challenges in security, robustness and realizability following the limitation of equipments and application environment. For pushing forward the applications of quantum secure multi-party computations, we should research them in non-ideal settings.In this thesis, we design and analyze some quantum secure multi-party computation protocols in some non-ideal settings. The non-ideal settings include the cases of imperfect source, lossy and noisy channel, imperfect operating equipments and detectors, the technological limitations on long-term quantum memory, and dishonest participants, etc. The researched protocols include the foundation of QSMPC:quantum key distribution (QKD), the basic protocols of QSMPC:general quantum secure multiparty computation (QSMPC-G), quantum bit commitment (QBC), and quantum oblivious transfer (QOT), one application of QSMPC:quantum private comparison (QPC). The special contributions of this thesis are described as following. With respect to QKD, we propose a QKD scheme based on interferometry and interaction-free measurement of single photons. Then we analyze the counterfactual QKD in practical lossy channel setting, and give an attack strategy depend on loss rate.As for basic protocols of QSMPC, we design a QBC based on pre-and post-selected states, a QOT scheme based on technological limitations on non-demolition measurements and long-term quantum memory. After these, we propose an attack to a QSMPC-G scheme in the dishonest participants setting, which can cheat other participant’s private information without being detected. Then we propose improved schemes.In QPC aspect, we give an attack to a QPC scheme in the dishonest participants setting, which could extract each private bit of the other participant with success probability2/3without being detected. Then we classify the previous QPC schemes, and point out that they are not realizable in practical noise setting. Finally, we propose a fault-tolerate QPC with distributed states, and a QPC against decoherence noise based on decoherence-free states.