Controllable keyword search scheme supporting multiple users

Abstract

In recent years, with the rapid growth of data, data processing in local place is becoming more and more difficult. With the help of cloud computing, more and more people store their data in the remote cloud servers, so that the local storage space can be saved. In order to protect the data privacy, data will be encrypted before uploading. Keyword search technique enables user to retrieve the corresponding files with the required keywords. In traditional keyword search scheme, all the files will be returned to users if they contain the required keywords. However, it is insecure in some cases. If the user has no right to read the files, he can also get the files, although he cannot decrypt them. The user obtains extra information of the files, i.e., the files contain the same required keyword though he/she cannot decrypt them. In this paper, a controllable keyword search scheme is proposed to address this issue. The files which the user has no right to access to cannot be retrieved, even if they contain the required keyword. This scheme is useful and practical especially under the circumstances with hierarchical user groups.