Patent ID: 7298844

Claim:
A recording/reproducing apparatus, comprising: a first storage section for storing data structure information which includes encrypted data; a special information holding section for holding special information associated with the data structure information; and a controller for controlling the first storage section and the special information holding section, wherein the data structure information and the special information are associated with each other such that the special information is updated in response to an update of the data structure information, or such that the data structure information is updated in response to an update of the special information, the controller controls movement of the encrypted data from the first storage section to a second storage section, and the controller updates the special information held in the special information holding section such that a mismatch occurs between the special information obtained before the movement of the encrypted data from the first storage section to the second storage section and the special information obtained after the movement of the encrypted data from the first storage section to the second storage section, wherein the data structure information includes: an object region for storing data which is encrypted using a title key corresponding to a predetermined unit amount of data; a management region for storing management information of the encrypted data; and an encryption region for storing the title key and the management information which are encrypted using a system key, wherein the special information is the system key, the controller controls a movement of a predetermined amount of content included in the encrypted data from the first storage section to the second storage section, the controller updates the system key every time the predetermined amount of content is moved from the first storage section to the second storage section, every time the predetermined amount of content is moved from the first storage section to the second storage section, the controller deletes the moved predetermined amount of content from the object region, updates the management information, and encrypts the title key and the updated management information using the updated system key, and when the amount of moved contents becomes equal to the predetermined unit data amount, the controller deletes from the encryption region the encrypted title key which is used for decrypting the data.