The success of the Internet of Things (IoT) depends heavily on the extent of achieved interoperability, as well as on addressing the many security and privacy challenges. Due to the multitude of types of devices, systems, and protocols, and their scale of deployment and limited resources, some of these systems will be extremely challenging to interconnect and secure. The underlying edge network or edge-computing infrastructure, supporting the IoT, will also need to provide security and privacy guarantees. Given that IoT devices and edge networks are deployed by a multitude of players, decentralization has become a key enabling design goal of the system. For example, recent advances in Distributed Ledger Technology (DLT) and Blockchains can be incorporated to support decentralized security. In turn, decentralized security through distributed trust can help overcome privacy concerns and scalability bottlenecks, both of which are becoming increasingly serious in large-scale deployments, such as smart cities or Industry 4.0. A decentralized approach to IoT interconnection brings forth many opportunities, but also important challenges, e.g., in state synchronization, trust management, and the difficulties of operating with constrained devices and networking modes. This SlideShare explores the concept of Decentralized Computing in IoT in brief.