Digital rights management system

摘要

The invention facilitates the offline extension of authorizations, which were issued online after a first user authentication. This is achieved using a second "extension" authentication procedure. Applications to Digital Rights Management (DRM) with support for domains and person-based access to content are described. Once a domain key is sent from an online server to a public rendering device after a first user authentication with a limited validity time, the validity time may be extended by subsequent user authentications without being connected to the server.