Abstract

Symmetric searchable encryption for cloud storage enables users to retrieve the documents they want in a privacy-preserving way, which has become a hotspot of research. In this paper, we propose an efficient keyword search scheme over encrypted cloud data. We firstly adopt a structure named as inverted matrix (IM) to build search index. The IM is consisted of index vectors, each of which is associated with a keyword. Then we map a keyword to an address used to locate the corresponding index vector. Finally, we mask index vectors with pseudo-random bits to obtain an encrypted enlarged inverted matrix (EEIM). Through the security analysis and experimental evaluation, we demonstrate the privacy and efficiency of our scheme respectively. In addition, we further consider two extended practical search situations, i.e., occurrence queries and dynamic user management, and then give two relevant schemes.