Introduction
In recent years, there has been enormous interest in applications of distributed ledger technologies (DLTs) to the realm of the Internet of Things (IoT). The motivation stems from the lack of a pervasive IoT trust layer: IoT applications are usually confined within their own ecosystem, making it difficult to share authenticated information among different applications. DLT is seen as an enabler of a distributed trust network that would be used by IoT devices to manage and exchange data without involving centralized control [1]. This would not only replace some of the existing centralized applications with their decentralized versions, but also lead to a wave of completely new applications, such as trusted access to edge computing resources [2].