Privacy and safety are the most needed features while accessing the data in the IoT. Due to the complicated decentralization and heterogeneous environment present in IoT, the security and privacy of the data becomes a challenging job for the developers. The current methods are not suitable for these scenarios where a decentralized and heterogeneous system exists. This paper provides a new method for access control in IoT based on the booming technology Block Chain, which helps the user in accessing or controlling their data. The contribution consists of a description of the model used to show how a blockchain is used for creating access control methods. To implement the method, the blockchain is taken as the decentralized access manager. The proposed method is validated with respect to the previous related work. Finally, the limitations and future work of the paper are discussed. Access Control Systems are proved to provide access control to critical resources. The right to access the resources is defined by the access control policies that are executed during the access request time.