Dynamic Verifiable Search Over Encrypted Data in Untrusted Clouds

The scalable and elastic storage capabilities of cloud computing motivate enterprises and individuals to outsource their data and query services to cloud platforms. Since the cloud service provider (CSP) is outside the trusted domain of cloud users, existing research suggests encrypting data before outsourcing and employing searchable symmetric encryption (SSE) to facilitate keyword-based search on the ciphertexts. To make SSE be more applicable in cloud computing, Kurosawa et al. proposed a dynamic verifiable SSE (DVSSE) scheme, which employed inverted indexes and the RSA accumulator to enable the user to search and update files in a verifiable way. However, their scheme works only under the assumption of an honest but curious CSP. In this paper, we propose a secure DVSSE scheme, \(\hbox {DVSSE}_{S}\), for the untrusted cloud environments. Specifically, \(\hbox {DVSSE}_{S}\) is constructed in two different ways. The basic \(\hbox {DVSSE}_{S}\), called \(\hbox {DVSSE}_{S}\)-1, is constructed based on the Merkle hash tree (MHT) and BLS signatures, which can be easily extended from DVSSE. Since \(\hbox {DVSSE}_{S}\)-1 incurs a heavy cost during the update phase, the advanced \(\hbox {DVSSE}_{S}\), called \(\hbox {DVSSE}_{S}\)-2, utilizes random permutations to improve the performance. Extensive experiments on real data set demonstrate the efficiency and effectiveness of our proposed scheme.