Blockchain for IoT Security

Nowadays, we are facing an exponential growth in the Internet of Things (IoT). There are over 8 billion IoT devices such as physical devices, vehicles and home appliances around the world. Despite its impact and benefits, IoT is still vulnerable against privacy and security threats, due to the limited resources of most IoT devices, lack of privacy considerations and scalability issues, thus making traditional security and privacy approaches ineffective for IoT. The main goal of this article is to investigate whether the Blockchain technology can be employed to address security challenges of IoT. At first, a Systematic Literature Review was conducted on Blockchain with the aim of gathering knowledge on the state-of-the-art usages of Blockchain technology. We found 44 use cases of Blockchain in the literature from which, 18 use cases were specifically designed for the application of Blockchain in addressing IoT-related security issues. We classified the state-of-the-art use cases in four domains, namely, smart cities, smart home, smart economy and smart health. We highlight the achievements, present the methodologies and lessons learnt, and identify limitations and research challenges.