  Access to the system resources. The current access control systems face many
problems, such as the presence of the third-party, inefficiency, and lack of
privacy. These problems can be addressed by blockchain, the technology that
received major attention in recent years and has many potentials. In this
study, we overview the problems of the current access control systems, and
then, we explain how blockchain can help to solve them. We also present an
overview of access control studies and proposed platforms in different domains.
This paper presents the state of the art and the challenges of blockchain-based
access control systems.
