The attack involves probing a digital key wirelessly by sending 65,000 challenge/response queries to it. Once the researchers collect 65,000 responses – which takes about an hour – they use software they designed to decipher that key's unique code. The deciphering currently takes about a day using a dedicated computer. But once they've cracked one key, they know 36 bits of the 64 bits they need to know. Those 36 bits are identical for every car model a manufacturer makes (different car models will vary only slightly).