Search on encrypted data: State of arts

Search on encrypted data is a method that can effectively search over ciphertext of data stored in the untrusted database and return correct results to querier, such that the querier can correctly decrypt the results. A well-defined search scheme on encrypted data is required not only to ensure the correctness of query results, but also to protect the privacy of the query message, i.e., the server who executes the search scheme cannot obtain any information of query messages from the returned results. In addition, the efficiency is an important criterion to measure a search scheme on encrypted data. It determines whether the scheme can be carried out effective in the real cloud computing environment. Therefore, the technology of search on encrypted data is a key factor in effective implementation of a variety of applications in the mode of database as a service (DaaS) in cloud computing, and also is an important measure of enterprise cloud database product selection. However, the existing schemes cannot fully satisfy the requirements of cloud database applications, encryption algorithms, security and efficiency are need to further improved. This paper begins with the system model of DaaS and the background of its applications, then surveys existing search schemes on encrypted data and their development and gives the analysis and comparison of these schemes, and proposes the new development directions of the technology of search on encrypted data.