A Blockchain Infrastructure for the Semantic Web of Things

The Semantic Web of Things (SWoT) improves the Internet of Things power by increasing resource representation capabilities through knowledge management and reasoning technologies adapted from the Semantic Web. This promotes information interoperability and decision autonomy. Nevertheless, trust and reliability issues remain basically unsolved. Large-scale, decentralized and dynamic infrastructures suffer from unpredictable volatility of nodes, which compromises resource availability. Trust and coordination are still difficult. Blockchain is increasingly used as a transactional data storage solution for distributed ledgers. It enables trustless collaboration by enforcing smart contracts and prevents data tampering by validating transactions through consensus protocols. This paper proposes a blockchain framework for SWoT contexts settled as a Service-Oriented Architecture. Nodes can exploit smart contracts for registration, discovery and selection of annotated services/resources. While semantic matchmaking enables relevant resource retrieval with logic-based ranking and explanation features, blockchain provides reliable transaction storage. A prototype has been developed by enhancing the standard Hyperledger Iroha framework. Application areas are discussed and experimental tests on a cluster of virtual nodes provide early insight on effectiveness, performance and scalability.