| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve the problem that in a data transmission system using a communication satellite, communication is easy to be wire-tapped and disturbed, since many unspecified receivers can receive information. <P>SOLUTION: A data distributer 10 applies duplicate encryption processing to digital data together with encryption processing using a cryptographic key depending on an identifier denoting a kind of the digital data and transmits the duplicate encryption data to a data receiver 30. The data receiver 30 receives the duplicate encryption data sent from the data distributer 10 through a satellite channel and applies decoding processing to the data by using respective decoding keys corresponding to the respective encryption keys. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
