Research On Private Query And Its Post-processing Based On Oblivious Quantum Key Distribution

The mutual penetration of symmetrically private information retrieval(SPIR)problem and quantum cryptography has formed a new research hotspot--quantum private query.Compared with the classical SPIR scheme based on mathematical difficulty of computational complexity,quantum private query has enormous advantages in terms of security,computational cost and communication overhead by virtue of the basic physical principles of quantum mechanics and the new features of quantum information technology.In addition,the quantum key distribution technology has theoretically unconditional security and eavesdropping detectability.This provides a new idea and method for secure multi-party computation such as SPIR.Following the research direction of quantum private query,based on the advantages of easy-to-implement,low overhead and high security of oblivious quantum key distribution technology,we make a deep research on the application of private query,and propose two OQKD-based private query applications,and further research on the post-processing method of private query in this dissertation.Specifically,the main work is as follows:1.Nearest private query is a special kind of location privacy protection problem.It is required that the user gets the closest private location information accurately in the database under the premise of ensuring the privacy of both parties.At present,all the existing schemes adopt the classical methods,and have the shortcomings of the high computational and communication complexities and the realization difficulty.In addition,it is difficult for the classic scheme to resist quantum attacks.In order to ensure its realization and high security,the OQKD technology is introduced for the first time,and then an OQKD-based nearest private query scheme is proposed.First,the scheme constructs a database to achieve the nearest position query,then uses the SARG04 QKD protocol to establish an oblivious key between the two parties,and finally implements the private query through the classical post-processing method.2.Combined with the needs of stock trading in real life,a flexible OQKD-based stock exchange database private query protocol is proposed.This protocol establishes a model of oblivious set-element mapping,and abstracts the stock transaction information into the mapping relationship of set elements.Then through the value of the parameters ? and k to control the oblivious key between the user and the database,and implements the private query through post-processing.The scheme can adapt to different size stock trading database,and not only has good flexibility,but also can improve the security of the user and the database,so it has broad application prospects.3.In order to solve the shortcomings of the existing post-processing methods in OQKD-based private query,a new post-processing method of oblivious quantum key distribution is proposed.It can make the data service center control the number of the user's known key accurately(But agreed in advance)according to specific application requirements,which can not only improve the security of the database,but also be better applied to some special database query services,such as some database query services which need to return the specified number of query results.