Certifying entity models, entities and data messages on IoT/WoT platforms via blockchain

The growing complexity and the increasing diffusion of applications exploiting both the Internet of Things (IoT) and the Web of Things (WoT) paradigms have led to the necessity of ensuring robust security and reciprocal trust in the management of huge amount of data from heterogeneous sources. The blockchain technology can satisfy these requirements, ensuring data integrity, univocity, and immutability of the data shared and saved in distributed IoT/IoW systems. In this paper, a deep analysis of requirements for Blockchain based IoT/WoT frameworks has been conducted. The main contributions include (i) formal implications of certifying integrity for data models and for the usage/certification of corresponding instances of entities/ devices and their time series messages in a platform that may present both non-certified and certified models, entities and data messages; (ii) automation of certification and verification processes, which implies mechanisms and formal rules; (iii) flexible certification of data messages enforcing efficiency and sustainability; (iv) support for multi-organization distributed solutions; (v) performance assessment. The solution has been validated with the interconnection to a private/permissioned blockchain developed using Hyperledger Fabric, while enforcing the solution on Snap4City federated network of platforms for applications in the domain of mobility. The research has been performed in the context of CN MOST, which is the national center on Sustainable Mobility in Italy, and within its flagship action OPTIFaaS.