For example, the smart door lock of an apartment that is rented out to tourists over the weekend. The use of what is known as a smart contract, a kind ... producer in Argentina sells beef steaks to France. Every cooler comes with a smart sensor. This records at all times the journeys undertaken by the meat, where ... The blockchain could also be used for the exchange of real goods, such as homes or cars. This is the idea behind Slock.it. According to this idea, any object