  Internet of Things (IoT) is reshaping the incumbent industry to smart
industry featured with data-driven decision-making. However, intrinsic features
of IoT result in a number of challenges such as decentralization, poor
interoperability, privacy and security vulnerabilities. Blockchain technology
brings the opportunities in addressing the challenges of IoT. In this paper, we
investigate the integration of blockchain technology with IoT. We name such
synthesis of blockchain and IoT as Blockchain of Things (BCoT). This paper
presents an in-depth survey of BCoT and discusses the insights of this new
paradigm. In particular, we first briefly introduce IoT and discuss the
challenges of IoT. Then we give an overview of blockchain technology. We next
concentrate on introducing the convergence of blockchain and IoT and presenting
the proposal of BCoT architecture. We further discuss the issues about using
blockchain for 5G beyond in IoT as well as industrial applications of BCoT.
Finally, we outline the open research directions in this promising area.
