For example, a car loan could be completely enforced digitally using a smart contract. The electronic wallet and digital car keys can act as binding collateral. If the person using the car is unable to pay the monthly lease payment, the smart contract could automatically execute a partial payment, or even lock the keys to prevent the car from opening. The lessee is required to keep his account funded to make regular payments, while the lessor is required to provide digital keys that make the car accessible. The two can simply come to terms with each other using a digital interface, resulting in a trustless contract.