© 2019 IEEE. The evolution of Internet of Things (IoT) enables addressing problems with limited human assistance. It offers communication across various modern smart city applications, for example, using communication technologies like wireless sensor networks that would generate a huge amount of data. It is imperative to maintain reliable and trustworthy interactions over things to guarantee proliferation of IoT applications. As these applications are being rolled out in many fields, sensitive data need to be safeguarded against misuse and/or leakage. Moreover, promptness and real-time responses should feature all IoT services. This paper explores, through an experimental framework, the integration of blockchain into IoT in order to investigate its impact, security enhancements, and limitations or open challenges it might bring. A private fork on Ethereum blockchain platform is developed to connect IoT devices (Raspberry pi) deployed to detect car crashes so, that, the process of insurance claims are expediated. The same scenario is also deployed on public Ethereum network in order to offer a comprehensive overview of both public and private blockchain platforms and their related security issues and challenges. The findings formulate a rigid foundation upon which a proper and efficient IoT paradigm can be provisioned to unlock blockchain technology potentials in different other domains besides IoT.