Patent ID: 8116452
Filing Date: 2012-02-14
Classification: G11B

Abstract:
1. 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 reception unit operable to receive a designation of the encrypted content; a read unit operable to read media information unique to the recording medium, from the recording medium; a judgment unit operable to acquire 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; 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, in a case in which 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 first protection method uses a media key assigned to the recording medium, and the second protection method that is different from the first protection method uses a license key assigned to the contract for use of the encrypted content, wherein (i) a content identifier of the encrypted content and (ii) associated key type information showing at least one of a media key and license key are included in said protection method information so as to generate an appropriate content key.