The Research Of Searchable Symmetric Encryption Over Cloud Data

The cloud computing treats computing as a utility and leases out the computing and storage capacities to the public individuals. In such a framework, the individual can remotely store her data on the cloud server, namely data outsourcing, and then make the cloud data open for public access through the cloud server.Note that the outsourced data may contain sensitive privacy information. It is often necessary to encrypt the private data before transmitting the data to the cloud servers.However, it is very hard to search over encrypted data. Symmetrical Searchable Encryption(SSE) has the important scientific significance and application value because it can support keyword based search over encrypted data efficiently. However,the existing research results cannot be applied into practical industry due to their limitations in terms of functionality, security and efficiency.To further improve the user’s experience on searching, an important and fundamental function is to enable the multi-keyword search with the comprehensive logic operations, i.e., the “AND”, “OR” and “NO” operations of keywords. This is fundamental for search users to prune the searching space and quickly identify the desired data. Moreover, it is a challenging issue to develop the dynamic version of searchable symmetric encryption(DSSE) which can support the document update operations. In a DSSE scheme, encrypted keyword search should be supported even if documents are arbitrarily inserted into the collection or deleted from the collection.Since the update operations may be executed on the cloud server, the information leakage must be precisely specified.This work addresses above issues by developing two SSE schemes over encrypted cloud data:? This paper introduces the relevance scores and the preference factors ofkeywords for searchable encryption. The relevance scores of keywords canenable more precise returned results, and the preference factors of keywordsrepresent the importance of keywords in the search keyword set specified bysearch users and correspondingly enables personalized search to cater tospecific user preferences. And this paper realizes the “AND”, “OR” and “NO”operations in the multi-keyword search for searchable encryption. Forefficiency, this paper employs the classified sub-dictionaries technique toenhance the efficiency of the above two schemes. Extensive experimentsdemonstrate that the enhanced schemes can achieve better efficiency in termsof index building, trapdoor generating and query in the comparison with otherschemes.? This paper proposes an efficient and secure dynamic searchable symmetricencryption scheme. It achieves strong security properties, i.e., forward andbackward privacy, which is a challenging issue in the DSSE area. Forward andbackward privacy is to ensure that the privacy of index, trapdoor anddocument will not be disclosed in insert and delete operations. Realperformance evaluation shows that our schemes are more efficient than otherrelated schemes.