  The Internet of Things (IoT) technology will soon become an integral part of
our daily lives to facilitate the control and monitoring of processes and
objects and revolutionize the ways that human interacts with the physical
world. For all features of IoT to become fully functional in practice, there
are several obstacles on the way to be surmounted and critical challenges to be
addressed. These include, but are not limited to cybersecurity, data privacy,
energy consumption, and scalability. The Blockchain decentralized nature and
its multi-faceted procedures offer a useful mechanism to tackle several of
these IoT challenges. However, applying the Blockchain protocols to IoT without
considering their tremendous computational loads, delays, and bandwidth
overhead can let to a new set of problems. This review evaluates some of the
main challenges we face in the integration of Blockchain and IoT technologies
and provides insights and high-level solutions that can potentially handle the
shortcomings and constraints of both IoT and Blockchain technologies.
