Patent ID: 7886361

Claim:
A storage medium processing method using a storage medium and a user terminal, the method comprising: storing, in the storage medium, medium identifier data, medium unique key data generated based on the medium identifier data, encrypted user key data in which user key data is encrypted so that the encrypted user key data may be decrypted using the medium unique key data, and encrypted content key data in which content key data is encrypted so that the encrypted content key data may be decrypted using the user key data; storing, in the storage medium, the encrypted user key data in a protection area, and storing the encrypted content key data in a user data area, the storage medium including the protection area in which data read/write is permitted from outside of the storage medium in response to authentication being accomplished, and including the user data area in which data read/write is permitted from outside of the storage medium; retaining, in the user terminal, encrypted content data in which content data is encrypted so that the encrypted content data may be decrypted using the content key data; and accessing, using the user terminal connected to the storage medium, a license center to obtain various kinds of data; an issuance step of issuing, in response to request from the user terminal, the content key data and the user key data with management data including data of an expiration date of the content key data or the user key data permitting use of the content data before a certain expiration date; a judgment step of judging whether or not the user key data or the content key data may be used continuously by referring to the management data; and a deleting/use-precluding step of deleting or precluding usage of the user key data or the content key data based on the judging result of the judgment step, wherein the user key data is issued so as to be shared by plural sets of the content key data, each of the plural sets having the same expiration date as that of the user key data shared among them.