Research On A Verifiable Encrypted Keyword Retrieval Protocol Supporting Strong Forward Securit

The growing pressure on data storage has made the management of massive data face challenges such as confidentiality protection and flexible search queries,searchable encryption emerged.Searchable symmetric encryption(SSE)allows users to achieve secure and efficient retrieval of encrypted data in the cloud without compromising retrieval privacy.In recent years,there have been numerous attacks against SSE protocols.Traditional forward security still leaks the connection between the updated data and the data stored in the cloud during next retrieval operation,leading to a statistical inference attack on the protocol and exposing the keyword information retrieved by the user.In addition,malicious clouds may return wrong retrieval results,making the reliability of retrieval results doubtful.Finally,the protocol has no authority restrictions on the retrieval personnel in the retrieval stage,which makes the retrieval user can retrieve data arbitrarily and expose the privacy of the data owner.Therefore,SSE is inadequate in security and verifiability.In order to solve the above problems,this paper conducts research on encrypted keyword retrieval protocols,and the research mainly includes:(1)Strong forward security keyword retrieval protocol with verifiable integrityTo address the problem that traditional SSE protocols with forward security are still subject to statistical inference attacks that leak retrieval patterns,this paper proposes the concept of strong forward security to ensure that the protocols are protected from such attacks.To achieve strong forward security,this paper designs a new index called Inversed Index with Retrieval Control(RC-II).In addition,to address the high local storage overhead associated with strong forward security,service nodes are introduced in the protocol to help the user bear part of the storage overhead.The verification algorithm is also designed in the protocol to realize the completeness verification of the retrieval results.(2)Multi-user conjunctive keyword search protocol with verifiable access rightsIn response to the problems of insufficient security and access rights of SSE in multi-user,conjunctive keyword scenarios,this protocol designs a novel double index structure Double Index(DI)-keyword index and file index.Based on the above index structure,one SSE scheme that supports both strong forward and backward security under multi-user and conjunctive keyword settings is proposed.The existence of the ring file index not only enables efficient deletion,but also hides the user access pattern well.In addition,the access right verification algorithm in the ring index is designed using bloom filters to reduce the communication overhead while limiting the user’s search privileges.