The present invention relates to a video signal transmitting apparatus, such as digital broadcast transmission equipment, VTRs and DVD players, and to a video signal receiving apparatus, such as television receivers or personal computer displays, VTRs and digital broadcast receiving terminals.
For broadcast of high quality image content by taking advantage of the widespread use of the digital broadcast service since 1998, there is a recognition that measures need to be taken to ensure that the broadcast content cannot be copied easily. To meet this requirement, a system has been proposed in which the content to be broadcast is encrypted by an apparatus on the transmitting side and the broadcast content is decrypted by an apparatus on the receiving side. In this system, when a receiving apparatus used has no key information for decryption, the decryption processing cannot be performed and thus the content not displayed. The system can also prevent the broadcast content from being copied, as it otherwise can be through connecting a VTR to an apparatus on the transmitting side. There is a growing consensus that, from the standpoint of copyright protection of the content, some increase in cost may be tolerated.