Between a transmitting device and a receiving device, a first authentication and key exchange procedure depending on a radio link layer network is carried out, and then a whole or a part of a second authentication and key exchange procedure depending on the copyright protected contents data is carried out by using the cipher communication using a first encryption key that is shared between the transmitting device and the receiving device by the first authentication and key exchange procedure, so that the contents data transfer by the cipher communication using a second encryption key can be carried out only between legitimate pair of the transmitting device and the receiving device that can successfully complete the first authentication.