Multicast message transmission device and message receiving protocol device for realizing fair message delivery time for multicast message

Claim 2

A receiving protocol device in a multicast communication system in which multicast messages are transmitted from at least one multicast transmission device to a plurality of receiving protocol devices belonging to an identical multicast group, the receiving protocol device comprising: a lower level interface unit for receiving each multicast message transmitted from the multicast transmission device; a release time setting unit for setting a release time of the multicast message received by the lower level interface unit to a prescribed time specified to all of said plurality of receiving protocol devices; a message storing unit for storing the multicast message received by the lower level interface unit until the release time set by the release time setting unit; and an upper level interface unit for releasing the message stored by the message storing unit to an upper level device provided in correspondence to said receiving protocol device, such that the multicast messages received by said plurality of receiving protocol devices are released from said plurality of receiving protocol devices to respective upper level devices simultaneously at the release time so as to realize an identical receiving time of the multicast message among users of the respective upper level devices.

Claim 3

The receiving protocol device of claim 1 , further comprising: an identifier storing unit for storing an identifier for identifying said receiving protocol device among said plurality of receiving protocol devices; a first protection mechanism for protecting the identifier in the identifier storing unit from an illegal access; and a second protection mechanism for protecting the identifier stored in the identifier storing unit from an illegal wiretapping at a time of authenticating the identifier at the multicast transmission device.

Claim 4

The receiving protocol device of claim 1 , further comprising: a decryption unit for decrypting the multicast message by using a decryption key, the multicast message being encrypted at the multicast transmission device by using an encryption key corresponding to the decryption key, so that the message storing unit stores the multicast message as decrypted by the decryption unit.

Claim 5

A multicast transmission device in a multicast communication system in which multicast messages are transmitted from at least one multicast transmission device to a plurality of receiving protocol devices belonging to an identical multicast group, the multicast transmission device comprising: an authentication unit for authenticating each receiving protocol device, by checking whether or not each receiving protocol device has a prescribed identifier, the prescribed identifier being a secret identifier assigned to each receiving protocol device as a proof of authenticity of a protocol implementation in each receiving protocol device; a transmission unit for transmitting the multicast messages encrypted by using an encryption key to the receiving protocol devices; and a key distribution unit for distributing a prescribed decryption key corresponding to the encryption key to those receiving protocol devices which are authenticated by the authentication unit, prior to transmissions of the multicast messages by the transmission unit.

Claim 6

A multicast transmission device in a multicast communication system in which multicast messages are transmitted from at least one multicast transmission device to a plurality of receiving protocol devices belonging to an identical multicast group, the multicast transmission device comprising: an authentication unit for authenticating each receiving protocol device, by checking whether or not each receiving protocol device has a prescribed identifier, the prescribed identifier being a secret identifier assigned to each receiving protocol device as a proof of authenticity of a protocol implementation in each receiving protocol device; a transmission unit for transmitting the multicast messages encrypted by using an encryption key to the receiving protocol devices; and a key distribution unit for distributing a prescribed decryption key corresponding to the encryption key to those receiving protocol devices which are authenticated by the authentication unit, prior to transmissions of the multicast messages by the transmission unit.

Claim 7

The multicast transmission device of claim 4 , wherein the authentication unit includes: an identifier storing unit for storing identifiers for identifying each of legitimate receiving protocol devices; and an identifier authentication unit for checking whether an identifier transmitted from each receiving protocol device matches with any of the identifiers stored in the identifier storing unit, and authenticating each receiving protocol device as an legitimate receiving protocol device when the identifier transmitted from each receiving protocol device matches with one of the identifiers stored in the identifier storing unit.

Claim 8

The multicast transmission device of claim 4 , wherein the authentication unit checks whether an identifier transmitted from each receiving protocol device matches with any of identifiers for identifying each of legitimate receiving protocol devices managed by an external authentication server, and authenticating each receiving protocol device as an legitimate receiving protocol device when the identifier transmitted from each receiving protocol device matches with one of the identifiers managed by the external authentication server.

Claim 9

A multicast communication device in a multicast communication system in which multicast messages are transmitted from at least one multicast transmission device to a plurality of receiving protocol devices belonging to an identical multicast group, the multicast communication device comprising: a receiving protocol device section functioning as one receiving protocol device, including: a lower level interface unit for receiving each multicast message transmitted from the multicast transmission device; a release time setting unit for setting a release time of the multicast message received by the lower level interface unit to a prescribed time specified to all of said plurality of receiving protocol devices; a message storing unit for storing the multicast message received by the lower level interface unit until the release time set by the release time setting unit; and an upper level interface unit for releasing the message stored by the message storing unit to an upper level device in correspondence to said multicast communication device, such that the multicast messages received by said plurality of receiving protocol devices are released from said plurality of receiving protocol devices to respective upper level devices simultaneously at the release time so as to realize an identical receiving time of the multicast message among users of the respective upper level devices; and a multicast transmission device section, including: an authentication unit for authenticating each receiving protocol device; a transmission unit for transmitting the multicast messages encrypted by using an encryption key to the receiving protocol devices; and a key distribution unit for distributing a prescribed decryption key corresponding to the encryption key to those receiving protocol devices which are authenticated by the authentication unit, prior to transmissions of the multicast messages by the transmission unit.

Claim 10

A multicast communication device in a multicast communication system in which multicast messages are transmitted from at least one multicast transmission device to a plurality of receiving protocol devices belonging to an identical multicast group, the multicast communication device comprising: a receiving protocol device section functioning as one receiving protocol device, including: a lower level interface unit for receiving each multicast message transmitted from the multicast transmission device; a release time setting unit for setting a release time of the multicast message received by the lower level interface unit to a prescribed time specified to all of said plurality of receiving protocol devices; a message storing unit for storing the multicast message received by the lower level interface unit until the release time set by the release time setting unit; and an upper level interface unit for releasing the message stored by the message storing unit to an upper level device in correspondence to said multicast communication device, such that the multicast messages received by said plurality of receiving protocol devices are released from said plurality of receiving protocol devices to respective upper level devices simultaneously at the release time so as to realize an identical receiving time of the multicast message among users of the respective upper level devices; and a multicast transmission device section, including: an authentication unit for authenticating each receiving protocol device; a transmission unit for transmitting the multicast messages encrypted by using an encryption key to the receiving protocol devices; and a key distribution unit for distributing a prescribed decryption key corresponding to the encryption key to those receiving protocol devices which are authenticated by the authentication unit, prior to transmissions of the multicast messages by the transmission unit.

Claim 11

The multicast communication device of claim 7 , wherein the receiving protocol device section further includes: an identifier storing unit for storing an identifier for identifying said multicast communication device among said plurality of receiving protocol devices; a first protection mechanism for protecting the identifier in the identifier storing unit from an illegal access; and a second protection mechanism for protecting the identifier stored in the identifier storing unit from an illegal wiretapping at a time of authenticating the identifier at the multicast transmission device.

Claim 12

The multicast communication device of claim 7 , wherein the receiving protocol device section further includes: a decryption unit for decrypting the multicast message by using a decryption key, the multicast message being encrypted at the multicast transmission device by using an encryption key corresponding to the decryption key, so that the message storing unit stores the multicast message as decrypted by the decryption unit.

Claim 13

The multicast communication device of claim 7 , wherein the authentication unit further includes: an identifier storing unit for storing identifiers for identifying each of legitimate receiving protocol devices; and an identifier authentication unit for checking whether an identifier transmitted from each receiving protocol device matches with any of the identifiers stored in the identifier storing unit or not, and authenticating each receiving protocol device as an legitimate receiving protocol device when the identifier transmitted from each receiving protocol device matches with one of the identifiers stored in the identifier storing unit.

Claim 14

The multicast communication device of claim 7 , wherein the authentication unit checks whether an identifier transmitted from each receiving protocol device matches with any of identifiers for identifying each of legitimate receiving protocol devices managed by an external authentication server, and authenticating each receiving protocol device as an legitimate receiving protocol device when the identifier transmitted from each receiving protocol device matches with one of the identifiers managed by the external authentication server.

Claim 17

The method of claim 12 , wherein the notifying step notifies the release time by transmitting a release time notice indicating the release time to said plurality of receiving protocol devices, and the method further comprises the steps of: receiving an acknowledge response for the multicast message from each receiving protocol device; re-transmitting the multicast message to every receiving protocol device from which the acknowledge response for the multicast message was not received within a prescribed time of each message transmission or re-transmission, up to a prescribed number of times Smax; receiving an acknowledge response for the release time notice from each receiving protocol device; and re-transmitting the release time notice to every receiving protocol device from which the acknowledge response for the release time notice was not received within a prescribed time of each release time notice transmission or re-transmission, up to a prescribed number of times Wmax.

Claim 18

The method of claim 12 , wherein the notifying step notifies the release time by repeatedly transmitting a release time notice indicating the release time to said plurality of receiving protocol devices at an interval over a prescribed time τi, for a prescribed number of times, and the method further comprises the steps of: receiving an acknowledge response for the multicast message from each receiving protocol device; re-transmitting the multicast message to every receiving protocol device from which the acknowledge response for the multicast message was not received within a prescribed time of each message transmission or re-transmission, up to a prescribed number of times Smax; and receiving a release result message from each receiving protocol device.

Claim 19

The method of claim 12 , wherein the notifying step notifies the release time by repeatedly transmitting a release time notice indicating the release time to said plurality of receiving protocol devices at an interval over a prescribed time τi, for a prescribed number of times, and the method further comprises the steps of: receiving an acknowledge response for the multicast message from each receiving protocol device; and re-transmitting the multicast message to every receiving protocol device from which the acknowledge response for the multicast message was not received within a prescribed time of each message transmission or re-transmission, up to a prescribed number of times Smax.

Claim 20

The method of claim 12 , wherein the notifying step notifies the release time by attaching a release time indication to the multicast message transmitted by the transmitting step, and the method further comprises the steps of: receiving an acknowledge response for the multicast message from each receiving protocol device; and re-transmitting the multicast message to every receiving protocol device from which the acknowledge response for the multicast message was not received within a prescribed time of each message transmission or re-transmission, up to a prescribed number of times Smax.

Claim 21

The method of claim 12 , wherein the notifying step notifies the release time by repeatedly transmitting a release time notice indicating the release time to said plurality of receiving protocol devices at an interval over a prescribed time τi, for a prescribed number of times, and the method further comprises the step of: receiving a release result message from each receiving protocol device.

Claim 22

The method of claim 12 , wherein the notifying step notifies the release time by repeatedly transmitting a release time notice indicating the release time to said plurality of receiving protocol device at an interval over a prescribed time τi, for a prescribed number of times.

Claim 25

The method of claim 19 , wherein the release time is notified from the multicast transmission device in a form of a release time notice transmitted from the multicast transmission device to each receiving protocol device, and the method further comprises the steps of: transmitting an acknowledge response for the multicast message to the multicast transmission device when the multicast message is successfully received; and transmitting an acknowledge response for the release time notice to the multicast transmission device when the release time notice is successfully received.

Claim 26

The method of claim 19 , wherein the release time is notified from the multicast transmission device in a form of a release time notice transmitted from the multicast transmission device to each receiving protocol device, and the method further comprises the steps of: transmitting an acknowledge response for the multicast message to the multicast transmission device when the multicast message is successfully received; and transmitting a release result message to the multicast transmission device when the multicast message is successfully released.

Claim 27

The method of claim 19 , wherein the release time is notified from the multicast transmission device in a form of a release time notice transmitted from the multicast transmission device to each receiving protocol device, and the method further comprises the step of: transmitting an acknowledge response for the multicast message to the multicast transmission device when the multicast message is successfully received.

Claim 28

The method of claim 19 , wherein the release time is notified from the multicast transmission device in a form of a release time indication attached to the multicast message transmitted from the multicast transmission device, and the method further comprises the step of: transmitting an acknowledge response for the multicast message to the multicast transmission device when the multicast message is successfully received.

Claim 29

The method of claim 19 , wherein the release time is notified from the multicast transmission device in a form of a release time notice transmitted from the multicast transmission device to each receiving protocol device, and the method further comprises the step of: transmitting a release result message to the multicast transmission device when the multicast message is successfully released.

Claim 30

The method of claim 19 , wherein the release time is notified from the multicast transmission device in a form of a release time notice transmitted from the multicast transmission device to each receiving protocol device.

Claim 31

The multicast transmission device of claim 4 , wherein the authentication unit authenticates each receiving protocol device by using a zero knowledge proof protocol.