Internet of Things (IoT) applications and services have become increasingly prevalent due to the fast evolution of wireless sensor networks, smart devices, and conventional information and communication technology. The data processed by IoT systems is enormous. This information may be extremely delicate because it relates to private matters such as health, finances, and whereabouts. Therefore, strong access control is essential for IoT's granular security management. Several solutions have been proposed to handle security for the Internet of Things. Although blockchain-based approaches are being developed for IoT access control, they are very briefly referenced. In this article, we look at the growing interest in and need for IoT access control systems that are built on the blockchain. In this article, we examine the pros and cons of using blockchain technology to get access to the Internet of Things, including distributed systems, safe data management, and trustless information exchange. Finally, we highlight several promising areas for further study on the merging of blockchain technology with Internet of Things networks.

Internet of Things, Blockchain, Security, Trust, Access control, Identity