Blockchain based Certificateless Privacy Preserving Public Auditing for Cloud Storage Systems

Abstract

With the increasing popularity of cloud storage systems, users often outsource their data to the cloud. Cloud-servers provide storage space at a low cost and reduce the burden of the users. Once the users outsource data to the cloud, they lose control over their data. Hence, the integrity of outsourced data is the main challenge. To address this issue, many public auditing schemes were proposed, based on third-party auditors (TPA). However, traditional public auditing schemes are vulnerable to malicious TPA who may not provide correct auditing results on time. To resist malicious TPA, blockchain-based public auditing schemes have been proposed recently. Although, blockchain-based auditing schemes avoid malicious auditors, they are suffering from the key escrow problem, because their design is based on identity-based signatures. To overcome the key escrow problem and malicious auditors, in this paper, we propose a Blockchain based Certificateless Public Auditing scheme for cloud storage systems. In security analysis, we prove that the proposed scheme is secure against the type I/II/III/IV adversaries. In experimental analysis, we show that the proposed scheme outperforms than existing schemes.