A Collusion Attack on Identity-Based Public Auditing Scheme via Blockchain

Abstract

With cloud storage systems, users can access and update outsourced data remotely. Owing to the accompanying growth of the importance of data integrity, a great deal of attention has been focused on public auditing schemes. Identity-based public auditing (IBPA) scheme allows a third-party auditor (TPA) to verify the integrity of the outsourced data on behalf of users. However, malicious TPAs might collude with cloud servers and forge audit data to deceive users. In this paper, we first review the architecture of a traditional IBPA scheme and a novel IBPA scheme which try to solve the above problem via blockchain. Then, we analyze two main limitations in this newly proposed public auditing scheme against malicious auditors and illustrate our collusion attack on this IBPA scheme. Finally, we offer some suggestions to overcome the disadvantages and help to create a more trustworthy blockchain-based public auditing scheme.