Patent ID: 7962154
Filing Date: 2011-06-14
Classification: H04L,H04W

Abstract:
1. A transmitting device for transmitting contents for which a copyright protection is necessary, to one or more receiving devices through a network, in a plurality of communication modes including a first mode in which wireless devices communicate by using a wireless base station and a second mode in which wireless devices communicate without using the wireless base station in a case of carrying out communications with receiving devices, the transmitting device comprising: a contents supply unit configured to store or generate the contents; a device authentication and key exchange processing unit configured to determine a receiving device number indicating a number of receiving devices with which communications can be carried out, such that the receiving device number used in the first mode is greater than the receiving device number used in the second mode, and to carry out device authentication and key exchange with receiving devices in number which is less than or equal to the receiving device number; an encryption processing unit configured to encrypt the contents by using a key exchanged by the device authentication and key exchange processing unit; and a network interface unit configured to transmit the contents encrypted by the encryption processing unit, to the receiving devices in number which is less than or equal to the receiving device number.