Efficient Privacy-Preserving Certificateless Provable Data Possession Scheme for Cloud Storage

Cloud computing is a burgeoning paradigm that offers reliable and adaptive infrastructure to the data owner who shares his data with the data user through the cloud server. In the data sharing process, the integrity of the data stored in the cloud faces serious threats. The provable data possession schemes ensure that a cloud server provider proves to a third party auditor that it is truthfully storing data from the data owner. However, the PKI-based provable data possession scheme suffers the management issue of the certificates and the identity-based provable data possession scheme causes an inherent key escrow problem. In this paper, we put forward an efficient privacy-preserving certificateless provable data possession scheme based on certificateless cryptography and elliptic curve cryptography, which has been proved to be unforgeable against adaptive chosen message attacks in the random oracle model. At the same time, the data integrity can be audited by the third party auditor without downloading the whole data. The proposed scheme gives away no information of the stored data to the third party auditor during the audit phase and the data owner's identity privacy is protected. The experiment results show that the proposed scheme is of efficiency and feasibility as far as computation and communication costs are concerned.