Article ID: 2021XBL0019
This paper addresses the scalability in the cost of smart contracts, which prevent illegal resource access (control access) in the Internet of Things. In previous studies, smart contracts have been used to avoid having a single point of failure, while maintaining tamper resistance. However, a high cost (called gas) is necessary when the number of subject-object pairs becomes large. In order to reduce cost, this paper proposes an access control method using smart contracts with a hierarchical name space. The proposed method scales well in terms of cost-decisive factors, namely, the complexity of functions and the number of smart contracts, leading to scalability in cost.