Abstract: Due to cloud computing it has become very popular for data owners to outsource data to public cloud servers while allowing data users to retrieve this data. For privacy concerns, a secure search over encrypted cloud data has motivated several research works under the single owner model. However most cloud servers in practice do not serve just one owner instead they support multiple owners to share benefits brought by cloud computing. In this system we propose schemes to deal with privacy preserving ranked multi keyword search in a multi owner environment to enable cloud servers to perform secure search without knowing the actual data of both keywords we systematically construct a novel secure search protocol. To rank the search results and preserve the privacy of relevance course between keywords and files, we propose a novel additive order and privacy preserving function family. To prevent the attackers from eavesdropping secret keys and pretending to be legal data owners submitting searches we propose a dynamic secret key generation key protocol and a new data user authentication protocol.

Keywords: Cloud computing, multi keyword search, user privacy