Internet of Things (IoT) that has been developed owing toward the merging of various technologies such as instantaneous analytics, machine learning, artificial neural network, product sensors and implanted systems, etc. It also stages a significant part in multiple applications which are a smart city, smart home, agricultural, health monitoring, tourism, transportation, communication, business, education, etc. The security concern associating IoT has to be situated in the direction to attract the research community due to its immensely growing application in our daily life. Since it is light-weight nature, the security mechanism needs changes apart from comprehensive web security. PKI based certificate driven techniques, which in some instances seem not appropriate on the way toward encounter IoT challenges, eg, as real-time effectiveness, costs, and performance from the security perspective. However, Blockchain has mind-blowing potentials to peer with the IoT aiming to build trust, transparency, and security. Its distinct properties, such as distributed behavior, immutability, and consensus mechanism, can stimulate and improve the rapidly growing IoT system through meaningful integration. We propose to address a practical smart home use case scenario using Ethereum Blockchain to improve IoT security. Public type and smart contract oriented Ethereum Blockchain are adaptable to enhance IoT security remains individual of the contributions that we claim throughout this research work.