To transmit digital data relating to programs such as a compressed image in a form of a transport stream by transmitting key data through the use of a multi-value QAM digital modulation means or the like, an information storage medium or an FSK digital modulation means or the like without scrambling the data.
A data multiplex and contents scramble circuit 111 scrambles video/audio data 151 into scrambled video/audio data 157, which are fed to a time division multiplex circuit 102. Furthermore, 1st key data 152 and 2nd key data 153 that are used to cipher the video audio data 151 into the scrambled video audio data 157 are also fed to the time division multiplex circuit 102. The time division multiplex circuit 102 applies time division multiplex processing to the ciphered 1st key information, 2nd key information and the scrambled video audio data 157 as digital data of a transport stream form to obtain the scrambled video/audio key information multiplexed data 158, which are fed to a 64 QAM modulation circuit 103.
NODA TSUTOMU
SHIROSUGI TAKATOSHI
SATO TOMOTAKE
NISHIDA MASAMI
TANAKA HIROMI
YAMADA TORU
TANAKA TOSHIYUKI
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