Improved one-round phrase search schemes over symmetrically encrypted data in storage outsourcing system

Abstract

Phrase search schemes over encrypted data are efficient methods for protecting users’ data privacy in storage outsourcing systems. We analyze and improve two one-round phrase search schemes over encrypted data. One drawback of F. Kong’s phrase search scheme is that it cannot support single-keyword search. We propose a modification and the improved scheme supports both single-keyword and phrase search. In M. Li’s phrase search scheme, a simple unkeyed hash function is used instead of a keyed pseudo-random function. We present a security analysis and show that the usage of a keyed pseudo-random function can resist the leakage of some useful information. These phrase search schemes can be applied in cloud storage.