Efficient public key encryption with revocable keyword search

Public key encryption with keyword search is a novel cryptographic primitive enabling one to search on the encrypted data directly. In the known schemes, once getting a trapdoor, the server can search associated data without any restrictions. However, in reality, it is sometimes essential to prevent the server from searching the data all the time because the server is not fully trusted. In this paper, we propose the notion of public key encryption with revocable keyword search to address the issue. We also develop a concrete construction by dividing the whole life of the system into distinct times to achieve our goals. The proposed scheme achieves the properties of the indistinguishability of ciphertexts against an adaptive chosen keywords attack security under the co-decisional bilinear Diffie-Hellman assumption in our security model. Compared with two somewhat schemes, ours offers much better performance in terms of computational cost. Copyright (c) 2013 John Wiley & Sons, Ltd.