Patent ID: 8719566

Claim:
A playback device for reading an application and a digital stream from a recording medium to execute the application with playback of the digital stream, the playback device comprising: a reading unit for reading information from the recording medium, the information including a disc root certificate, a first root certificate, the application, a provider ID identifying a provider organization that gives the application authorization to use files, a leaf certificate containing an organization ID matching the provider ID, a second root certificate associated with the leaf certificate, and playlist information defining a playback path of the digital stream, wherein the disc root certificate is a third root certificate issued by a root certificate authority and assigned to the recording medium; a management unit configured to verify authenticity of the application by judging whether the disc root certificate is identical to the first root certificate; an execution unit configured to execute the application if authenticity of the application is verified by the management unit; a storage unit having a storage area that is specified by a file path that uses the provider ID and a hash value of the second root certificate; a playback unit configured to play back the digital stream in accordance with the playlist information; and a processing unit configured to execute the application to issue a request to access the storage area by designating a file path containing the provider ID, and to (i) convert the designated file path into a file path that uses the provider ID and the hash value of the second root certificate associated with the leaf certificate containing the organization ID matching the provider ID, and (ii) give the application authorization to use files in the storage area specified by the file path obtained by the conversion.