Decentralized Cloud Storage: A Systematic Review on the Role of Blockchain Technology in Enhancing Security, Privacy, and Data Integrity
This systematic literature review (SLR) investigates the role of blockchain technology in achieving secure decentralized cloud storage. This review synthesizes evidence from 65 peer-reviewed publications (2018–2025) addressing security mechanisms, consensus protocols, privacy-preserving techniques, and scalability challenges in blockchain-enabled decentralized storage systems. Thematic analysis identified four primary focus areas: (1) Security Mechanisms including cryptographic foundations, consensus-based verification, and smart-contract-enabled access control; (2) Consensus Protocols and their performance-security tradeoffs; (3) Privacy-Preserving Techniques addressing the transparency-confidentiality tension; and (4) Technical Challenges including scalability, energy consumption, and regulatory conflicts. Evidence synthesis reveals that while blockchain-based approaches are commonly reported to improve security and auditability compared to centralized cloud storage, methodological limitations and lack of real-world deployments constrain definitive effectiveness claims. This review contributes by: (a) systematically documenting blockchain's technical mechanisms for storage security; (b) identifying critical deployment barriers and their theoretical bases; (c) clarifying the privacy-security tradeoff landscape; and (d) directing future research toward empirical validation and production-ready implementations. The study recommends future research on hybrid blockchain architectures, energy-efficient consensus algorithms, advanced privacy techniques, and more empirical validations to overcome these limitations and promote real-world adoption.