Efficient searchable ID-based encryption with a designated server

Public key encryption with keyword search (PEKS) is a mechanism that allows one to extract e-mails containing a particular keyword by providing a trapdoor corresponding to the keyword. And parties without the trapdoor are unable to learn any information about the extracted e-mails. Meanwhile, a PEKS scheme is also suitable to provide a secure storage system in cloud computing environment. However, in a PEKS scheme, a secure channel must be established to transmit trapdoors. A PEKS scheme with a designated server, termed dPEKS, removes the requirement of the secure channel while retaining the same functionality of PEKS. Up to date, the related studies on dPEKS are all based on the pairing-based public key system. No work focuses on dPEKS based on ID-based systems, termed dIBEKS. In this article, we propose the first dIBEKS scheme that possesses the advantage (removing certificate management) of ID-based systems. Security analysis is given to demonstrate that our scheme is provably secure and can resist off-line keyword guessing attacks. When compared with previously proposed dPEKS schemes, our scheme has better performance in terms of computational time.