Abstract
The Internet of Things (IoT) represents a new technology that enables both virtual and physical objects to be connected and communicate with each other, and produce new digitized services that improve our quality of life. The IoT system provides several advantages, however, the current centralized architecture introduces numerous issues involving a single point of failure, security, privacy, transparency, and data integrity. These challenges are an obstacle in the way of the future developments of IoT applications. Moving the IoT into one of the distributed ledger technologies may be the correct choice to resolve these issues. Among the common and popular types of distributed ledger technologies is the blockchain. Integrating the IoT with blockchain technology can bring countless benefits. Therefore, this paper provides a comprehensive discussion of integrating the IoT system with blockchain technology. After providing the basics of the IoT system and blockchain technology, a thorough review of integrating the blockchain with the IoT system is presented by highlighting benefits of the integration and how the blockchain can resolve the issues of the IoT system. Then, the blockchain as a service for the IoT is presented to show how various features of blockchain technology can be implemented as a service for various IoT applications. This is followed by discussing the impact of integrating artificial intelligence (AI) on both IoT and blockchain. In the end, future research directions of IoT with blockchain are presented.