International Journal of Computer Science and Technology

International Journal of Computer Science and Technology | Vol. 1, No. 8, August 2020 | pp. 57–64

Research Article

Title: Blockchain-Based Provable Data Possession Scheme for Secure and Auditable Cloud Data Storage

Names of Authors: Liam O'Connor¹, Sophie Martin², and Antoine Dubois³

Authors’ Affiliations:
¹School of Computer Science, University College Dublin, Dublin, Ireland
²Department of Computer Science, Sorbonne University, Paris, France
³Department of Informatics, Technical University of Munich, Munich, Germany

Abstract: Cloud data outsourcing relieves enterprises and individual users from local hardware maintenance overheads, but it introduces severe trust deficits regarding data integrity. Since cloud service providers (CSPs) may accidentally corrupt files or deliberately hide data loss incidents to protect their reputation, third-party public auditing schemes are necessary. Conventional public auditing architectures rely on a centralized Third Party Auditor (TPA), which can become a single point of failure, collude with dishonest CSPs, or compromise privacy guarantees. This paper proposes a decentralized, blockchain-based Provable Data Possession (PDP) scheme that eliminates the need for a trusted central auditor while ensuring strict data integrity verification. The proposed scheme uses homomorphic authenticators computed on client data blocks before cloud upload, allowing the verifier to check data integrity without downloading the original files. Verification challenges and cryptographic proof responses are recorded and validated through smart contracts deployed on a public-permissioned blockchain ledger, guaranteeing tamper-proof audit trails and automated micro-payment settlements upon successful verification. Performance benchmarks demonstrate that computation time for tag generation scales linearly at 1.8 ms per megabyte (MB), and on-chain verification gas costs remain economically viable. Security analysis confirms that the protocol ensures provable data security, withstands forge attacks, and protects data privacy against malicious auditors.

Keywords: Cloud storage, Provable data possession, Blockchain, Smart contracts, Data integrity, Public auditing

Manuscript Timeline: Received: May 14, 2020; Revised: June 18, 2020; Accepted: July 14, 2020; Published: August 1, 2020

Citation: O'Connor, L., Martin, S., & Dubois, A. (2020). Blockchain-based provable data possession scheme for secure and auditable cloud data storage. International Journal of Computer Science and Technology, 1(8), 57–64. DOI: 10.46882/2020/IJCST/000008

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