Verifiable Searchable Encryption Research In A Cloud Computing Environment

As a new computing model,Cloud computing realizes long-cherished dream that is "computing as a facility".Owing to the convenient features and flexible charging methods of cloud computing,both enterprises and individuals are willing to outsource their data to the cloud.It not only makes users enjoy the high-quality applications and services provided by the cloud,but also ease the burden of users on locally data storage,management and maintenance.However,once the data is stored in the cloud,uses will lose physical control of data.To protect the confidentiality of the outsourcing data,users usually encrypt the data before outsourcing.But data encryption makes the data search under the plaintext field be no longer applicable.Searchable encryption is proposed to solve this problem,which not only ensures the confidentiality of outsourcing data,but also achieves the efficient retrieval of ciphertexts.Most of the proposed schemes currently are assumed that cloud server is "honest-but-curious".In practice,the cloud server may deviate from the established rules and return incorrect search results to users.On the one hand,due to the software/hardware failure or suffering from external attacks,the cloud server may return wrong search results;on the other hand,the cloud server may return incomplete results in order to save its computing resources.Therefore,how to design a secure verifiable searchable encryption scheme has become an important research topic in the cloud storage research field.The main points in this paper are as follows:(1)We propose a Bloom filter based verifiable searchable encryption scheme.By using Bloom filter as secure indexes for searching,we construct verifiable set for keywords and files,which can verify whether the cloud storage server returns all of the search results,tampers and deletes documents.The scheme achieves efficient single keyword search and also supports the verification of search results.(2)Considering that users are accustomed to search multiple keywords,we propose a verifiable multi-keyword searchable encryption scheme based on the proposed single keyword scheme.Through security analysis and experimental analysis,we demonstrate the feasibility and efficiency of the scheme.(3)We further investigate the problem of keywords update on the basis of the multi-verifiable keyword searchable encryption scheme.We use a Counting bloom filter to conduct a secure index.The security analysis and experimental analysis shows that thescheme meets the requirements of data privacy,and has low overhead on updating keywords as well.