Blockchain-based Resource Registration in Constrained IoT Environments

The interconnection of devices in Internet of Things (IoT) networks results in a ubiquitous exchange of resources between clients and servers. This interaction involving multicast discovery requests in classical Service oriented Architectures is hardly applicable for IoT nodes that go through sleep phases to conserve energy. CoRE Resource Directory (RD) provides a CoAP-based solution, including a central node where the server registers its resources, and the client requests them. Nevertheless, the centralization of operations makes this node a point of failure vulnerable to DDoS attacks and causes a mistrusted authentication between RD and endpoint devices. The Blockchain (BC) is a valuable solution for building decentralized, trustless peer-to-peer networks that enable reliable and non-repudiable data exchange. However, its application in IoT environments is a real challenge due to the computing and storage constraints of the devices. In this paper, we propose a novel architecture based on a distributed network of RDs acting as validators in a permissioned blockchain. The aim is to safeguard the resource registration phase and define the type of data stored in the BC ledger. Three approaches are proposed, implemented, and evaluated by exploiting Hyperledger Iroha Blockchain and a CoAP library called CoAPthon. The differences between approaches regarding storage size, usability, and security are highlighted. The assessment results show the impact of each approach and discuss the possibility of a combined solution concluding with their applicability in the proposed architecture to further secure the CoAP resource registration.