Blockchain-Enhanced Outsourced Provable Data Possession with Zero-Knowledge Proofs for Secure Cloud Storage

Abstract

The rapid proliferation of cloud storage services necessitates robust mechanisms for verifying data integrity without requiring complete data retrieval. Traditional Provable Data Possession schemes face significant challenges in achieving simultaneous decentralization, privacy preservation, and efficient dynamic data handling. We present a novel framework that integrates blockchain technology with zero-knowledge cryptography to comprehensively address these limitations. Our approach employs Ethereum smart contracts for decentralized verification orchestration, Groth16 zk-SNARKs for privacy-preserving proof generation, and IPFS for distributed metadata management. The system architecture features a hierarchical Merkle tree authentication structure combined with BLS signature aggregation, achieving logarithmic verification complexity that is independent of the dataset size. By leveraging blockchain's immutable ledger properties, we eliminate single points of failure inherent in centralized third-party auditor models while ensuring complete audit trail transparency. The protocol supports dynamic data operations, including insertions, deletions, and modifications, through efficient cryptographic re-authentication mechanisms. We implement homomorphic encryption to enable verification on encrypted data, ensuring cloud providers never access plain-text information. Experimental evaluation on realistic datasets demonstrates a 43% reduction in computational overhead, a 67% decrease in communication costs, and 99.9% verification accuracy compared to existing approaches. When processing 10,000 data blocks totalling 1 GB, our system achieves a 2.3 -second average verification time with only 1.2% storage overhead. Formal security analysis proves correctness, soundness under computational hardness assumptions, and zero-knowledge privacy guarantees.