Patent ID: 7933409

Claim:
A content playback device for decrypting encrypted content recorded on a non-transitory computer readable recording medium and playing back the decrypted content, comprising: a read unit operable to read media information unique to the recording medium, from the recording medium; a judgment unit operable to acquire, from a source other than the recording medium, contract information relating to a contract for use of the encrypted content, and judge, based on the acquired contract information, whether the encrypted content is permitted to be used; a reception unit operable to receive a designation of the encrypted content; an acquisition unit operable to acquire protection method information showing one of a first protection method and a second protection method that is used for protecting the encrypted content; a generation unit operable to generate a content key, corresponding to the acquired protection method information, based on the read media information and the acquired contract information, if the encrypted content is judged as being permitted to be used; a decryption unit operable to read the encrypted content from the recording medium, and decrypt the encrypted content using the generated content key; and a playback unit operable to play back the decrypted content, wherein the encrypted content includes at least first-type encrypted content that is protected by the first protection method and a second-type encrypted content that is protected by the second protection method different from the first protection method, wherein a content identifier of the encrypted content and associated key type information including at least one of a media key and license key is included in each of said protection method information so as to generate an appropriate content key.