Bitmap-based distributed index structure and encrypted query processing schemes for outsourcing mobile sensitive data

As the outsourcing of mobile sensitive data has been highlighted, data encryption schemes are required to protect the mobile sensitive data. Accordingly, it is necessary to develop not only a distributed index structure to efficiently manage the large amount of encrypted data, but also a query processing scheme over the encrypted data. To the best of our knowledge, there has been no research on index structure for the encrypted data. Meanwhile, the existing query processing schemes over the encrypted data can support limited types of queries. Also, without decrypting data, the existing schemes cannot support operations among data between different columns because they use different types of encryption schemes depending on their attribute types. To solve the problems, in this paper, we propose a bitmap-based distributed index structure and a query processing scheme for the encrypted data. The proposed distributed index structure guarantees data privacy preservation and performance improvement for the various types of queries. In addition, by processing a query over the encrypted data without data decryption, the proposed query processing scheme provide both high query performance and 100% accuracy while preserving the data privacy. Finally, we show from our performance analysis that our proposed index structure and query processing scheme are suitable for protecting the data privacy of the mobile sensitive data.