| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To carry out communication by multicasting without oppressing a transmission band while keeping secrecy. <P>SOLUTION: A terminal station device 1 is equipped with a multicast cipher key table storage part 13 which stores a stream number, multicast conditions, an object terminating device identifier, and a multicast cipher key and when a received transmission frame meets the multicast conditions, the terminal station device sets a header to broadcast communication, sets a corresponding stream number in the header, and ciphers the transmission frame with the multicast cipher key. A terminating device 2 is equipped with a multicast cipher key table storage part 22 which stores a stream number and a multicast cipher key, and deciphers the transmission frame by a corresponding multicast cipher key when the header of the received transmission frame is set to broadcast communication and the stream number set in the header is present in the multicast cipher key table storage part 22. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
