Blockchain and smart contracts are widely used in IoT access control to create decentralized, trustworthy environments for secure access and record management. However, their application introduces a dual challenge: The transparency of blockchain and the use of addresses as identifiers can expose account privacy. To tackle this issue, this paper proposes a blockchain-based IoT access control system that enhances account anonymity and preserves privacy, particularly regarding user behavior, habits, and access records through the use of zero-knowledge proofs. The system incorporates an access control mechanism that combines access control lists with capability-based access control, enabling ownership verification of access rights without disclosing identity information. To evaluate the system’s feasibility, we conduct experiments in a smart building scenario, including both qualitative comparisons with existing methods and quantitative analyses of performance in terms of time, space, and gas consumption. The results indicate that our scheme achieves the best time efficiency in the proof generation and authorization phases, completing them in just 7 and 10 s, respectively—representing half the time required by the second-best approach. These findings underscore the system’s superior cost efficiency and enhanced security compared to existing solutions.

The rapid proliferation of IoT devices has increased demand for data integration platforms to efficiently utilize sensor data. While centralized platforms remain dominant, they suffer from structural issues, including platform dependency, privacy risks, and data distribution constraints. To address these challenges, various studies have explored decentralized blockchain-based approaches to build reliable systems. However, existing approaches often focus on specific aspects and have not yet led to practical platforms. This paper proposes a decentralized IoT data distribution system that enables secure data exchange. It also supports diverse distribution needs through integrated processing and flexible external service integration. We implemented a prototype and evaluated its feasibility, confirming that the system can operate with reasonable costs and computational resources. Furthermore, we developed a highly portable system and released it as open source, contributing to the advancement of decentralized IoT platforms.