Patent ID: 7940935

Claim:
A content playback apparatus that decrypts encrypted content recorded on a recording medium, thereby obtaining content, and plays the content, the recording medium having recorded thereon a plurality of pieces of encrypted content respectively in correspondence with a plurality of pieces of management source information, each piece of management source information showing, from among a plurality of management source apparatuses, a management source apparatus that manages usage of the corresponding piece of encrypted content based on corresponding playback control management performed by the management source apparatus, the content playback apparatus comprising: a processor; a designation acquisition unit operable to acquire a designation of one of the pieces of encrypted content; a management source acquisition unit operable to acquire, from among the pieces of management source information recorded on the recording medium, a piece of management source information that corresponds to the designated piece of encrypted content; a key information acquisition unit operable to acquire, from the management source apparatus shown by the acquired piece of management source information, a piece of key information that shows usage permission for the designated piece of encrypted content; a decryption unit operable to generate, using the processor, a content key based on the acquired piece of key information, and generate a piece of content by decrypting the designated piece of encrypted content with use of the generated content key; and a playback unit operable to play the generated piece of content, wherein at least one of the pieces of management source information includes a plurality of pieces of candidate information, each piece of candidate information showing a different one of a plurality of candidate apparatuses that are candidates for the management source apparatus pertaining to the piece of encrypted content corresponding to the piece of management source information, and wherein the key information acquisition unit includes: a candidate information judgment sub-unit operable to judge whether the acquired piece of management source information includes pieces of candidate information; an acquisition-destination determination sub-unit operable to, when the judgment is affirmative, select one of the pieces of candidate information included in the acquired piece of management source information; and a key information acquisition sub-unit operable to, when the judgment is affirmative, acquire, from the management source apparatus, which is the candidate apparatus shown in the selected piece of candidate information, the piece of key information showing usage permission for the designated piece of encrypted content, and when the judgment is negative, acquire the piece of key information from the management source apparatus shown by the piece of management source information.