An integrity hash is obtained of rights information stored at a client device. The rights information is associated with content stored at the client device. The integrity hash is encrypted using a client device key to generate an encrypted hash. The client device key is externally inaccessible from...http://www.google.fr/patents/US7949877?utm_source=gb-gplus-shareBrevet US7949877 - Rights enforcement and usage reporting on a client device
Rights enforcement and usage reporting on a client device
