Using FIWARE and blockchain in smart cities solutions

Nowadays, Blockchain has been widely used to store decentralized and secure transactions involving cryptocurrency, e.g., Bitcoin, Ethereum, etc. However, Blockchain can also store other types of information besides monetary transactions. On the other hand, innovative solutions for smart cities are concerned with how services and information can be safely stored and shared. For this reason, smart city systems can benefit from using Blockchain to integrate their data and services. These smart solutions also demand consistency and standardization across the industry. However, this Blockchain integration varies according to its implementation. FIWARE, a framework of an open-source platform for smart solutions, adopts NGSI Standards (Context Information Management (CIM); NGSI-LD API: Tech. Rep., CIM and ETSI Industry Specification Group (ISG), 2020) to enable the integration of components and provides the basis for interoperability and portability among smart solutions. Unfortunately, FIWARE does not support any integration with Blockchain technology. Hence, this paper proposes a set of new components to allow FIWARE to be integrated with Blockchain technology. With these proposed components, it is possible to support Blockchain technology with smart city applications via the FIWARE platform. For instance, we have designed and implemented a FIWARE Blockchain adapter to submit/listen to transactions from/to FIWARE Context Broker to/from any Blockchain implementation without human intervention. In addition, we present a global post-pandemic vaccination case study to evaluate the proposed approach in the Smart City context.