Briefing
Cloud storage currently faces significant challenges including ensuring data security, mitigating high storage costs from redundancy, preventing privacy leakage during deduplication and auditing, and simplifying complex key management, often relying on untrustworthy third-party auditors. This paper proposes a blockchain-based framework that integrates Identity-Based Broadcast Encryption (IBBE) for efficient key management and employs randomized file tags and audit proofs to protect user ownership privacy. Smart contracts are deployed on the blockchain to autonomously perform integrity auditing, thereby eliminating the need for a fully trusted third-party auditor. This new theory significantly advances the practicality and efficiency of cloud storage services by ensuring data confidentiality, reducing redundant storage, and establishing a robust, decentralized auditing mechanism.
Context
Before this research, cloud storage solutions struggled to balance data confidentiality with efficient deduplication, as existing methods often revealed user ownership during tag deduplication or required users to manage an increasing number of encryption keys. Traditional auditing schemes frequently relied on centralized, fully trusted third-party auditors (TPAs), posing a single point of failure and trust assumption that undermined the decentralized ethos of many digital systems. The prevailing theoretical limitation centered on creating a system that could perform both secure deduplication and verifiable integrity auditing without compromising privacy or introducing centralized vulnerabilities.
Analysis
The core mechanism is a blockchain-smart contract system that orchestrates privacy-preserving data deduplication and integrity auditing in cloud storage. This model introduces randomized file tags and audit proofs, ensuring that even if public on the blockchain, user file ownership remains confidential. A key differentiator is the integration of Identity-Based Broadcast Encryption (IBBE), which allows for efficient key management by enabling users to recover encryption keys without interacting with a central key server, thus making key storage costs independent of the number of files. This approach fundamentally differs from prior methods by simultaneously addressing privacy leakage in deduplication, centralizing key management burdens, and the reliance on trusted third-party auditors through a cohesive, decentralized cryptographic framework.
Parameters
- Core Concept → Identity-Based Broadcast Encryption
- New System/Protocol → Blockchain-Based Deduplication and Auditing Scheme
- Key Authors → Qingyang Zhang et al.
- Auditing Mechanism → Smart Contracts
- Privacy Enhancement → Randomized File Tags and Audit Proofs
Outlook
This research lays a robust foundation for future decentralized cloud storage solutions, particularly those requiring stringent privacy and auditability. In the next 3-5 years, this theoretical framework could enable the development of fully autonomous, privacy-preserving cloud storage services where data integrity is verifiably maintained without any single point of trust. New avenues of research include optimizing the computational overhead of broadcast encryption for larger user bases and exploring its application in other privacy-sensitive distributed systems beyond cloud storage, such as secure data marketplaces or confidential federated learning environments.
