Study Of Multi-User Setting Keyword Search Over Outsourced Encrypted Database In Cloud Environment

With the flourish of cloud computing, the owner of information resources are eager to share their resources to authorized users by dint of the massive data storage and vast computation capabilities of the cloud computing platform. Searchable encryption which allows users to perform searching operation over the encrypted database provides an effective method to achieve the encrypted information resources authorized access.In this paper, we focus on the multi-user setting keyword search over outsourced encrypted database in cloud environment. Almost all existing multi-user searchable encryption schemes in cloud environment are based on re-encryption, and these schemes have some practicability problems and security issues. Thus, we put forward three new multi-user setting keyword search schemes over outsourced encrypted database in cloud environment.Focusing on verification of query results, we propose our efficient, multi-user setting, verifying completeness and integrity encrypted keyword query scheme. Our scheme utilizes digital signature structure binding keyword index and encrypted data file to achieve completeness verification of query results and integrity verification of data file. Our scheme realizes multi-user privacy preserving query, applies dynamical permission management, and deploys hash query index architecture to realize the rapid access of cloud data.Focusing on the security of query trapdoor, we put forward a new multi-user public encryption with keyword search scheme to solve the privacy preservation of query trapdoor against attacking from outside attacker. We enhance the trapdoor generation algorithm and randomize the query trapdoor to realize the preservation of query trapdoor. We can proof that our scheme can achieve encrypted index security(PEKS security) and outside trapdoor security. The encrypted keyword index will not leak any information of the keyword to the cloud server and external attacker,and the external attacker can not obtain keyword information of trapdoor even the query trapdoor is captured. Moreover, Our scheme actualizes the dynamic permissionmanagement in multi-user setting by granting or revoking the searching permission of query user.Focusing on issue of anonymous query, we propose an anonymous, dynamically updatable multi-user setting, keyword searchable encryption scheme. We put forward a new authorization management mechanism to achieve dynamic multi-user query setting.We separate the specific access control module from the encrypted database to realize multi-user searchable encryption. In our scheme which is based on access control module, the anonymous query can be realized and the data owner can direly control the update of query permission by altering the access control module. Indeed, unlike most exist schemes only consider the update of index query permission, our scheme considers both update of index query permission and the update of data file decryption. The permission management in our scheme is more practical and deployable.