VIDEO RECEIVING DEVICE, VIDEO DATA RECEIVING SYSTEM AND AUTHENTICATION CONTROL METHOD THEREOF
Television viewing can be performed at a video receiving device which receives an authentication, even if the power of a video receiving device which performs the authentication is turned off by a video data receiving system in which video receiving devices are connected to one another via a network for authentication, each of the video receiving devices having: an authentication unit which has an authentication function; and an authentication privilege management unit which manages an authentication privilege for enabling the authentication function, wherein the authentication unit of the video receiving device having an authentication privilege can permit other video receiving devices to receive the external video data, and when the power of the video receiving device having the authentication privilege is turned off, the power of the video receiving device is turned off after the authentication privilege management unit of the video receiving device has delegated the authentication privilege to other video receiving devices which have been connected to the network and with which links have been established.
1 . A video data receiving system in which multiple video receiving devices are connected to one another via a network for authentication, each of said multiple video receiving devices comprising:
a power control unit which senses an instruction of turning off power and an instruction of turning on the power;
a video data receiving unit which receives at least external video data;
a network interface unit which connects to said network for the authentication;
an authentication unit which has an authentication function; and
an authentication privilege management unit which manages an authentication privilege for enabling said authentication function of said authentication unit,
wherein said authentication unit can permit other video receiving devices to receive said external video data, by said authentication function, and
when the power of a predetermined one of the video receiving devices having said authentication privilege is turned off, the power of said predetermined video receiving device is turned off after said authentication privilege management unit of said predetermined one of the video receiving devices has delegated said authentication privilege to any of other video receiving devices which have been connected to said network and with which links have been established.
2 . The video data receiving system according to claim 1 , wherein said multiple video receiving devices are one master video receiving device and one or a plurality of slave video receiving devices which are other than said master video receiving device, and
if the power is turned on in a state where said master video receiving device does not have said authentication privilege, when a link with said slave video receiving device having said authentication privilege has been established in said network, said authentication privilege is delegated from said slave video receiving device to said master video receiving device.
3 . The video data receiving system according to claim 2 , wherein said master video receiving device is provided with a recording unit which records said video data received by said video data receiving unit.
4 . The video data receiving system according to claim 1 , wherein the video receiving device having said authentication privilege retains said authentication privilege until the power of that video receiving device is turned off.
5 . The video data receiving system according to claim 1 , wherein when the power of the video receiving device having said authentication privilege is turned off, said authentication privilege management unit of that video receiving device has previously stored which video receiving device is the video receiving device to which said authentication privilege has been delegated among other video receiving devices.
6 . The video data receiving system according to claim 5 , wherein when the power of the video receiving device having said authentication privilege is turned on again, said authentication privilege management unit of that video receiving device notifies information related to the video receiving device to which said authentication privilege has been delegated.
7 . The video data receiving system according to claim 1 , wherein when the power of the video receiving device having said authentication privilege is turned off, a warning is notified if there is no other video receiving device with which the link has been established in said network.
8 . The video data receiving system according to claim 1 , wherein said power control unit has a function capable of turning off the power for operating other functions while the power for operating at least said network interface unit, said authentication unit and said authentication privilege management unit is turned on, and
when the power of the video receiving device having said authentication privilege is turned off, if there is no other video receiving device with which the link has been established in said network, the power for operating other functions is turned off while the power for operating said network interface unit, said authentication unit and said authentication privilege management unit is turned on.
9 . The video data receiving system according to claim 1 , wherein said other video receiving device to which said authentication privilege management unit of said predetermined one of the video receiving devices delegates said authentication privilege is determined based on statistical information related to frequency of usage of each of said multiple video receiving devices.
10 . The video data receiving system according to claim 1 , wherein said external video data is broadcast program data from a cable television station, and
each of said video receiving devices is an STB for a cable television.
11 . The video data receiving system according to claim 10 , wherein said network is a cable network which uses a cable used for transmitting said broadcast program data.
12 . A video receiving device comprising:
a power control unit which senses an instruction of turning off power and an instruction of turning on the power;
a video data receiving unit which receives at least external video data;
a network interface unit which connects to a network for authentication;
an authentication unit which has an authentication function; and
an authentication privilege management unit which manages an authentication privilege for enabling said authentication function of said authentication unit,
wherein said authentication unit permits other video receiving devices to receive said external video data, by said authentication function, and
when the power is turned off in a state of having said authentication privilege, the power is turned off after said authentication privilege management unit has delegated said authentication privilege to any of other video receiving devices which have been connected to said network and with which links have been established.
13 . An authentication control method for a video data receiving system in which multiple video receiving devices are connected to one another via a network for authentication, each of said multiple video receiving devices having a power control unit which senses an instruction of turning off power and an instruction of turning on the power; a video data receiving unit which receives at least external video data; a network interface unit which connects to said network for the authentication; an authentication unit which has an authentication function; and an authentication privilege management unit which manages an authentication privilege for enabling said authentication function of said authentication unit, said method comprising:
an authentication step in which said authentication unit permits other video receiving devices to receive said external video data, by said authentication function, and
an authentication privilege delegation step in which when the power of a predetermined one of the video receiving devices having said authentication privilege is turned off, said authentication privilege management unit of said predetermined one of the video receiving devices delegates said authentication privilege to any of other video receiving devices which have been connected to said network and with which links have been established, before the power is turned off.
14 . A recording medium which can be used in a computer, having recorded a program which causes a computer to execute said authentication step in which said authentication unit permits said other video receiving devices to receive said external video data, and said authentication privilege delegation step in which said authentication privilege management unit of said predetermined one of the video receiving devices delegates said authentication privilege to any of other video receiving devices which have been connected to said network and with which the links have been established, of an authentication control method for a video data receiving system according to claim 13 .