>Modern cars are protected against thefts by using a smart key that talks to the car and exchanges cryptographic messages so that the key proves to the car that it’s genuine. [...] The thieves found a simple way around this: they used a hand-held radio relay station that beams the car’s message into the home to where the keys are kept, and then relays the message from the keys back to the car. The car accepts the relayed message as valid because it is - the real keys were used to unlock the car. Now that people know how a relay attack works generally possible to defeat it: car owners keep their keys in a metal box

? The car talking to the key first? Can't the key just not talk to the car at all unless the button is pressed on the key fob or shortly thereafter?