Blockchain assisted privacy-preserving public auditable model for cloud environment with efficient user revocation

摘要

Abstract Cloud storage offers users to manage their remote data more efficiently. However, it comes with the threat of severe security concerns, i.e., integrity. Public auditing models have been intensively researched with the growing importance of data integrity. These public auditing models employed a third-party auditor (TPA) to check the integrity of stored data on behalf of users. However, these models are susceptible to procrastinating auditors who may not conduct the scheduled auditing on time. Therefore, this paper introduces a blockchain-based methodology to employ a certificateless public auditing model against malicious and procrastinating auditors with efficient user revocation to address these issues. It enables the storage of immutable time-stamped auditing results as a transaction on the blockchain. So, the users can verify whether TPA performs the auditing task on the scheduled time. This model supports efficient batch auditing in multiple cloud servers without an additional trusted organizer. A formal security analysis guarantees the computational intractability and the performance analysis illustrates the feasibility and practicability of the model.