Extension On The Function Of Searchable Encryption

Compared with traditional LAN storage,”cloud storage” appeals to more andmore enterprises and personal users by its economical advantage and convenient man-agement. But the data privacy and security has become the biggest obstacles to itsprevalence. How to make use of the convenience and economical advantage broughtby”cloud storage” without the sacrifce of the data privacy has become a hot researchtopic currently.The research of this paper is mainly focused on the special indexes for encrypt-ed documents stored in Cloud–an untrusted third party server, which enable the cloudsever search over documents without decryption according to the query sent from theclient, with as little information leaked as possible. Up to now, a number of efcientschemes have been proposed in support of single-keyword search and conjunctive key-word search. However, there still remains a problem for phrase search over encrypteddocuments efciently and the conjunctive keywords search in a multi-user scenario.With a survey conducted on current searchable encryption technologies, we em-ployed proxy encryption to support both encryption and conjunctive keywords searchfor group users, at the constant computing cost for each document for each query.Our scheme supports dynamic group management, which updates group without key-redistributionorre-encryption. Besides,weproposedanothersecureschemeforphrasesearch over encrypted documents with moderate computing complexity and commu-nication cost. We proved that the former one is adaptive indistinguishable secure andthe latter one is non-adaptive indistinguishable secure.