A receiver for a radio broadcast signal, in particular a car radio, and a method for receiving a radio broadcast signal, including a signal decoder for decoding an audio signal contained in the radio broadcast signal in encoded form, and/or for decoding a data signal contained in the radio broadcast signal in encoded form, the signal decoder being operable so that the encoded signal is only decoded, when the signal decoder obtains an external authentication signal, which is received via an external transmission path that is different from the transmission path of the radio broadcast signal.