| 主权项 |
1. A method for authenticating a radio key for a vehicle, the method comprising:
determining a distance between the radio key and the vehicle; and authenticating the radio key; generating a character string independent of an item of information transmitted by the vehicle; transmitting the character string generated by the radio key to the vehicle to determine the distance between the radio key and the vehicle, wherein the authentication is carried out based on the character string, wherein the determination of the distance includes a propagation time measurement carried out by transmitting a first radio signal from the vehicle to the radio key, and transmitting a second radio signal transmitted from the radio key to the vehicle, wherein either the second radio signal is transmitted by the radio key as soon as the first radio signal is received by the radio key, or the first radio signal is transmitted by the vehicle as soon as the second radio signal is received by the vehicle, and wherein the authentication begins only after the two radio signals have been received. |
