Patent ID: 6850914
Filing Date: 2005-02-01
Classification: G06F,G11B

Abstract:
1. A revocation information updating method for updating revocation information on a storage medium, the storage medium (1) being capable of recording and playing back a digital content when used by an electronic appliance having at least one of a function for playing back a digital content and a function for recording a digital content and (2) storing, in advance, revocation information that is used to judge which electronic apparatuses should be prevented from using the storage medium to protect digital contents, the revocation information updating method comprising: (a) a recording step for recording a first set of information into a special storage region provided on the storage medium including master revocation information that is judgeable by special electronic appliances that have special permission to update the revocation information, and at least one set of revocation information for identifying electronic appliances that should be revoked to protect contents; (b) (i) for judging, when a storage medium has been loaded into an electronic appliance that has special permission to update the revocation information, whether to revoke the ability of the electronic appliance, that has special permission to update the revocation information, based on the first identification information and the master revocation information, (ii) for terminating processing upon a judgment in step (i) that the electronic appliance should be revoked, (iii) for judging, upon a judgment in step (i) that the electronic appliance should not be revoked, whether the electronic appliance should be revoked, based on the second identification information and the updateable revocation information in the sets of revocation information,