The Snap4City blockchain can be used in multiple domains. For example, in the context of mobility and transport it could be used to certify the way we interact with the world, connecting everyday devices/entities, in the cities and industries to certify: (i) distribution of goods and services in last mile collaborative framework, such as city hubs; (ii) vehicle identity, mileages, maintenance operations, reparation from incidents, on board unit data for insurances, on board unit data for professional drivers (to certify their readiness and attention level); (iii) tickets sold on the Mobility as a Service platforms, MaaS, also using it for revenue sharing towards the operators of multimodal traveling; (iv) computation of KPI indicators of the city with the aim of comparing them with other cities and for taxation, etc. In environmental applications, it can be used to certify measured values of pollution metrics, which are used for city taxations and to assess the achievement of the targeted values according to the European Commission. In the context of health to certify the source of organs and blood and their delivery chain of cold, the process for cleaning surgery instruments and hospital sheets, etc. In the context of energy and gas, it can be useful to certify the energy produced and exchanged in the communities of energies. It can also be used to certify, unicity, ownership and/or provenance of digital content, art, collectibles, and more through NFTs (Non-Fungible Tokens) that are unique digital assets authenticated on an immutable ledger. Blockchain can enhance smart home applications in regard to the fundamental security goals of confidentiality, integrity, and availability.
In the literature many specific frameworks have been developed, while the IoT/WoT platforms may be used to implement all those cases. IoT/WoT platforms are capable to manage device messages exchanged with any kinds of data/device structure. In this context, a strong push on defining data models has been realized, for example the FIWARE Smart Data Models, SDM. A data model provides a formal template format for IoT/WoT entity/messages with formalized variables/attributes including data types, units, etc., to produce identical entities, and this process should be certified as well. As to the platforms under analysis, messages from IoT devices are freely shaped, to assure data flexibility. For example, IBM Watson uses formats such as JSON or XML, without supporting FIWARE SDMs, which also are published in several versions over time. The IoT/WoT models are the formal template from which the devices/entities can be generated/registered, and in turn the devices/entities with their registration formalize the structure of the messages which can be received/sent on them by the brokers and storage. Whenever a message arrives from a device (which can partially provide pieces of information into its body, typically not the metadata, since most devices minimize data transmission), the platform is not capable to register the device, nor to correct the message link to former devices.
Snap4City added blockchain on IoT/WoT infrastructure adding a set of general-purpose features for certification/verification, and at the same time leaving flexibility to the developers of IoT/WoT solutions, allowing them to use the blockchain technology to set up their scenarios with a mix of certified and non-certified entities in a federated distributed architecture. The main contributions are on: (i) certification of any kind of IoT/WoT data models, devices and messages (with a particular focus on the certification of data models and its implications); (ii) automation of certifications according to the relationship among models and devices/entities, and among devices/entities and messages to guarantee consistency; (iii) certification of the hash for data messages by defining specific rules to cope for the flexibility of JSON objects of the simple schema validation; (iv) certification of time series, within a certain interval, for example to certify a trip, a mission, a delivery travel, etc.; (v) an architectural multi-organization solution to guarantee satisfactory performance in the certification of messages which is the most critical performance aspects.
The blockchain support is accessible via Entity/IoT Directory in which the developer can:
· Specify which Entity Models have to be certified, implying the production of Entities / Devices which are certified.
· Specify which Entities Instances / IoT Devices have to be certified, implying that messages on them will be certified
· Verify the certifications performed over time, on the time series of the devices / entities.
The developers can use these facilities to implement a large range of applications: voting, access rights, rewards, revenue distribution, healthiness, driver assessment, emission of coupons, digital collection, NFT, complimentary currencies, loyalty tools, crowdfunding, etc.
Ask to Snap4City@disit.org to get information and support to use this advanced feature on Snap4City.org infrastructure and on MicroX installations.