Mitigating Centralization in Access Control System with Blockchain and Distributed Storage

Cloud data storage service has drawn increasing interest from both academics and industry in recent years due to its efficiency and low cost. To protect sensitive data leakage, attribute-based encryption is an efficient method for achieving fine-grained access control over encrypted data. However, these systems often use a centralized server to store ciphertext, lacking Byzantine resilience and performance bottlenecks. In this work, we propose a novel data access control scheme that applies blockchain and secret sharing to address these concerns. Combining secret sharing, Erasure Code, and blockchain, we achieve Byzantine fault tolerance for both Byzantine data owners and Byzantine nodes. The security and experimental analysis for the system is also presented. The test results indicate that the time cost and bandwidth usage both grow linearly as the number of nodes and attributes increases.