  The Internet of Things (IoT) has become a guiding technology behind
automation and smart computing. One of the major concerns with the IoT systems
is the lack of privacy and security preserving schemes for controlling access
and ensuring the security of the data. A majority of security issues arise
because of the centralized architecture of IoT systems. Another concern is the
lack of proper authentication and access control schemes to moderate access to
information generated by the IoT devices. So the question that arises is how to
ensure the identity of the equipment or the communicating node. The answer to
secure operations in a trustless environment brings us to the decentralized
solution of Blockchain. A lot of research has been going on in the area of
convergence of IoT and Blockchain, and it has resulted in some remarkable
progress in addressing some of the significant issues in the IoT arena. This
work reviews the challenges and threats in the IoT environment and how
integration with Blockchain can resolve some of them.
