A trustless architecture for blockchain-based IoT applications using constrained devices

Despite the increasing interest in blockchain as a possible solution to replace centralized IoT architectures, previous work failed to provide a direct role for the sensing devices, i.e., direct interaction with the blockchain without additional components. Moreover, few studies focus on permissionless blockchains, even if it is the most secure platform for developing blockchain-based applications. This thesis presents an architecture that considers constrained sensing devices as direct actors on a public blockchain network. A public blockchain network allows the seamless inclusion of several unknown actors, and smart contracts provide a platform to develop complex IoT applications. The research followed an iterative DSR approach; designing, building, and evaluating new IT artifacts using two case studies in the agricultural IoT domain. These cases fostered two exploratory studies that diverged from the main IoT domain; however, they also provide novel contributions to blockchain-based applications. Thus, the novel architecture tackles three problems of current blockchain-based IoT systems i) constrained sensing devices as direct actors on a blockchain system, ii) permissionless blockchain networks and iii) smart contracts as an IoT application platform. Furthermore, the exploratory analyses examine two challenges of blockchain-based applications i) user experience and monetary costs and ii) data sharing and decentralized storage.