Blockchain Applied to Vehicular Odometers Fraud in automobile odometers is a billion dollar problem worldwide. The technical requirements behind any solution for this problem go through the perennial, secure, and immutable registration of vehicular data. Such requirements immediately raise the question of how blockchain technology could be used for this purpose. In this article, the requirements, design choices, and construction details of a blockchain architecture for vehicular odometers are presented and discussed. The architecture advances the state of the art by adopting a more efficient consensus algorithm than the traditional ones, such as proof of work. Results from a prototype proof ofconcept of the proposed architecture validate the solution, which is able to validate a new block in the blockchain every two seconds. Applicability in real scenarios is one step ahead and very promising.

Blockchainbased Reputation for Intelligent Transportation Systems A disruptive technology often used in finance, Internet of Things (IoT) and healthcare, blockchain can reach consensus within a decentralised networkxe2x80x94potentially composed of large amounts of unreliable nodesxe2x80x94and to permanently and irreversibly store data in a tamperproof manner. In this paper, we present a reputation system for Intelligent Transportation Systems (ITS). It considers the users interested in traffic information as the main actors of the architecture. They securely share their data which are collectively validated by other users. Users can choose to employ either such crowdsourced validated data or data generated by the system to travel between two locations. The data saved is reliable, based on the providersxe2x80x99 reputation and cannot be modified. We present results with a simulation for three cities: San Francisco, Rome and Beijing. We have demonstrated the impact of malicious attacks as the average speed decreased if erroneous information was stored in the blockchain as an implemented routing algorithm guides the honest cars on other free routes, and thus crowds other intersections.