A method for authorizing an off-line image device to play contents in use of a recording medium, including recording an encrypted key on a recording medium; recording contents on the recording medium using the encrypted key; and recording information as to a play right to play the contents recorded on the recording medium. Thus, the off-line image device can be authorized to play contents in use of the recording medium. As a result, the off-line image device can play contents that are recorded on the recording medium and must be authorized to play the contents.