Research And Design Of Private Query Of Block Based On Quantum Oblivious Key Transfer

The symmetric private information retrieval problem is designed to protect the privacy and security of both communicating parties.It allows the user to retrieve only one item from the database while avoiding revealing the retrieval address to the owner of the database.However,the classic schemes of symmetric private information retrieval were based on mathematically difficult assumptions and are vulnerable to quantum computer attacks.With the further development and application of quantum mechanics in the field of information processing,the security of information theory introduced by quantum mechanics has been confirmed in some protocols.For example,quantum key distribution,quantum secure direct communication,quantum machine learning,quantum private query with information theory security.As a practical quantum private query protocol,quantum oblivious key transfer-based private query protocol has unique advantages in resisting channel loss and being used for large database,which has more practical significance than the earlier Oracle-based private query protocols.In this paper,we make an in-depth study on the practicability and security of QOKT-based private query protocols and design two kinds of private protocols for block query.With the aid of a two-dimension quantum system,a practical quantum private query of block is proposed.In this scheme,a flexible two-dimension quantum system is used for controlling the user to obtain information about the final key.For different database sizes,the expected number of the user's known bits can be adjusted to any predetermined value,which ensures higher database security and a lower failure probability.Secondly,the proposed reorder-shift-addition operation severs two-fold purpose of embedding error correction process and compressing user's additional information obtained in this process.Resort to a special permutation-shift-addition operation,a quantum private query of block protocol based on RRDPS-QKD is proposed.The RRDPS-QKD system is applicable to distributing oblivious keys between the user and the database.It guarantees that the user can always exactly obtain the position of one of the pluses for each transmitted pulse sequence.In addition,the permutation-shift-addition operation is adopted to accomplish a difficult task in post-processing part,that is,to quickly realize ideal database security while eliminating the probability of failure.More important,our solution can also maintain this features even under imperfect sourcecondition.