Blockchain-Based Shared Data Integrity Auditing and Deduplication

Data deduplication and integrity auditing based blockchain plays an important role in guaranteeing secure and efficient cloud storage services. However, existing data deduplication schemes support auditing either with the assistance of a trust center (key server or third-party auditor) or bear the waste of computation and storage resources caused by repetitive authenticators storage and key storage. In this paper, we propose a blockchain-based shared data integrity auditing and deduplication scheme. Specifically, we propose a deduplication protocol based on ID-based broadcast encryption without key servers and achieve key deduplication on the user side. Next, we propose a data integrity auditing protocol by using the characteristic of convergent encryption to achieve authenticator deduplication on the cloud service provider side. Besides, we achieve decentralized data integrity auditing based blockchain without relying on a single trusted third-party auditor and improve the credibility of the auditing result. On this basis, we propose two bath auditing protocols for different scenarios to improve efficiency. Security and performance analysis demonstrates that the authenticators' storage cost on the cloud storage provider side can be reduced from {O} ({F}) to {O} (1) and the key storage cost on the user side can be reduced from {O} ({F}) to {O} (1) as well.