Patent ID: 7269741

Claim:
A recording apparatus for writing an encrypted content to a user data area of a semiconductor memory card, the semiconductor memory card including: an authentication circuit for authenticating an apparatus to which the semiconductor memory card is connected; and a protected area which is accessed by the apparatus only when the apparatus has been authenticated by the authentication circuit, a plurality of entry set files and a file condition management file being recorded in the protected area, each of the entry set files including a fixed number of entry areas and entry condition information that includes a flag sequence having a plurality of flags that correspond one-to-one with the plurality of entry areas in a single file, each flag being set as one of an off-flag showing the corresponding entry area to be unused, and an on-flag showing the corresponding entry area to be in use, and the file condition management file including file condition information that indicates, for each of the entry set files recorded in the protected area of the semiconductor memory card, whether the entry set file is in a first condition in which one or more entry areas are not in use, or in a second condition in which all the entry areas are in use, and said recording apparatus comprising: an authenticating unit operable to perform mutual authentication with the authentication circuit of the semiconductor memory card; a reading unit operable to read the file condition management file from the protected area in the semiconductor memory card in a case of legitimacy being authenticated by the mutual authentication; a specifying unit operable to specify, from among the plurality of entry set files recorded in the protected area of the semiconductor memory card, an entry set file in the first condition by referring to the file condition information in the read file condition management file, and acquire entry condition information in the specified entry set file; a writing unit operable to write one of a decryption key and rights management information that both relate to the encrypted content, to an entry area corresponding to the off-flag, from among the plurality of entry areas in the specified entry set file; and an updating unit operable to update the file condition management file in the protected area of the semiconductor memory card so as to show an entry set file as being in the second condition if all the entry areas therein become in use as a result of the writing of the data by said writing unit.