Research On Primitives Of Secure Multi-party Quantum Computation

Quantum information technology and secure multi-party computation technique are hot fields in physics and computer science, respectively. The former is a newly emerged interdiscipline between physics and information science. Quantum information theory applies the basic principles to areas such as computation, communication and cryptography, etc., and thus forms three branches—quantum computing, quantum communication and quantum cryptography. Quantum information technology outperforms its classical counterpart in computing speed, communication efficiency and security. The latter is the new direction of cryptography. Secure multi-party computation (SMC) protocols have been an important and fruitful area of research for modern cryptography. In this setting, there is a group of participants who wish to perform some joint task, despite the fact that some of the participants in the protocol may cheat in order to obtain additional information or corrupt the outcome. SMC shows wide prospect of applications in finance, military affairs, politics and medical treatment.The combination of quantum information technology and SMC technique gives birth to a new research area, which is so-called secure multi-party quantum computation (SMQC).Compared to those in classical SMC, primitives in SMQC achieve enhanced security, soundness and communication efficiency as a result of SMQC introducing excellent properties of quantum information technology. Particularly in wire-tapping detection, the former is too far behind to catch up with the latter.Owing to historical reasons, quantum cryptography has been the pronoun of quantum key distribution. Presently, research interest of scholars at home and abroad mainly focuses on quantum key distribution. They pay less attention to the other primitives in SMQC. In particular, unconditionally secure bit commitment, be it in quantum environment or in classical environment, is believed by most of them to be impossible. It is a great blow to scholars who dedicate themselves to SMQC. With this concern, the main research content of this dissertation consists of:1) Studying the properties of secure multi-party computation primitives and applying them to more complex protocols and applications.2) Lucubrating quantum computation and computing technologies, specially those correlative to quantum cryptographic primitives.3) Constructing secure multi-party quantum computation primitive protocol cluster and exploring its applications in practical situations.4) Investigating the proof, theory of secure protocols in quantum environment and putting special focus on anti-attacking and anti-eavesdropping ability of those schemes.Corresponding to it, the main contributions of this dissertation are as follows:1) We have constructed a series of protocols for secure mufti-party computation primitives. Specially, we have proposed multiple schemes for quantum key distribution and quantum oblivious transfer. They are designed for particular purposes, which result in better security, convenience and fault-tolerance ability.2) In quantum information technology aspect, a strictly mathematical deduction is made for unambiguous measurement. The conclusions to relative problem are obtained and applied to the protocols for those primitives and security proofs.3) As for quantum bit commitment, we have devised a new commitment model which play an important role in game theory, anonymous communication and multi-party computation. Based on this new model, we present practical schemes for both classical and quantum environment. The unconditional security of these schemes is also been ensured.4) In regard to the security proof of secure quantum protocols, this dissertation has provided rigorous mathematical proofs for them by means of the law of large numbers and other related principles of probability theory. Moreover, the security proofs do not rely on any assumption of computational intractability, i.e., the computing power of the adversaries can be seen as infinite. Thus the protocols presented in this dissertation are all unconditionally secure.This work was supported by the NSF of China (Grant No. 60773032, 60573171 and 60703071 respectively), the Ph.D. Program Foundation of Ministry of Education of China (No. 20060358014), the Natural Science Foundation of Jiangsu Province of China (No. BK2007060), the Anhui Provincial Natural Science Foundation (No. 070411043), and the Outstanding Ph.D. Training Program of USTC.