Patent ID: 7545943

Claim:
A content playback apparatus comprising: a segment key file selecting unit that selects one segment key file from plural segment key files at playback of content from a sequence key section in a recording medium, the recording medium storing a video object which has n sequence key sections and the segment key files, each sequence key section being groups of contents formed from m pieces of encrypted contents with different minute portions, each segment key file registering n key entries corresponding to each sequence key section, each key entry associating segment identification information that uniquely identifies a content to be played back among the m contents in the sequence key section with a segment key that is used for decrypting a content corresponding to the segment identification information, n and m being natural numbers; a content selecting unit that selects each content corresponding to the segment identification information of the n key entries registered in the selected segment key file; a content decrypting unit that decrypts each selected content by a segment key corresponding to the segment identification information of each selected content; and a playback unit that plays back each decrypted content.