An Efficient and Secure Multilevel Keyword Ranked Search for Encrypted Data

Abstract

with the growing digital communication and networks, the data owners are motivated to outsource their complex data to the global storage space. Greater flexibility and economic saving are the advantages of this global storage space. Before outsourcing the sensitive data, it has to be encrypted in order to enforce the data privacy. In the encrypted data, search service is important to get the necessary data. The stored data is relatively large so it requires multiple keywords in the search query and it will return document in the order of their relevance to these keywords searched. Related works on searchable encryption focus on single keyword search or Boolean keyword search and rarely sort the result and for the multi-keyword search coordinate matching, i.e., as many matches as possible, to effectively capture the relevance of outsourced documents to the query keywords and inner product similarity to evaluate such similarity measure. In Multi-keyword Ranked Search under the coordinate matching, the ranking helps for the efficient retrieval. The multilevel keyword ranked search is implemented by using the cache to reduce the search time.