Mobile access and flexible search over encrypted cloud data in heterogeneous systems.

Never before has data sharing been more convenient with the rapid popularity and wide adoption of cloud computing. However, mobile access and flexible search with security for outsourced data in heterogeneous systems are two major obstacles prior to practical deployment of cloud computing. To meet the requirements in secure mobile access and flexible search to sensitive data, this paper, for the first time, proposes a versatile primitive referred to as an identity based proxy re-encryption system with outsourced equality test (IBPRE-ET). This primitive allows a data owner in an identity based broadcast encryption system (IBBE) seamlessly to share his/her data with a data sharer in an identity based encryption system (IBE). Moreover, it supports a data sharer in an IBBE system to perform search functionality on ciphertexts related to a data sharer in an IBE system. We also formally prove that the proposed IBPRE-ET system is selective secure using a random oracle model. Meanwhile, the theoretic evaluation and experimental result demonstrate our scheme is practical in the heterogeneous system. Finally, we show an application of our IBPRE-ET to the collaborative office automation system.