Contents distribution system, recording apparatus, signature apparatus, contents supply apparatus, and contents playback apparatus

摘要

Second content relating to first content recorded on a portable recording medium is prevented from being illegally used. A contents supply apparatus outputs signature data and the second content to a playback apparatus, the signature data having been generated based on content information relating to at least one of the first and second content, with use of first key information. A distribution apparatus that distributes the first content outputs second key information corresponding to the first key information. The playback apparatus verifies the signature data with use of the second information, and plays back the second content when the verification is successful.