A DRM System Protecting Consumer Privacy

Digital rights management (DRM) is widely used to protect intellectual property for content owners but consumer privacy is sacrificed. A user's playing statistics can be collected by the client DRM module and the license server. In this paper, we propose a DRM system in which the license server can generate the content decryption key for a user to play an encrypted content object without gaining any information to link to the specific content object encrypted by the content encryption key. This is achieved by applying a (partially) blind signature primitive in the license acquisition protocol and by adopting a key scheme that a content encryption key depends on the information retrieved from the content object and a secret that only the license server knows. By requesting that the client DRM module does not send any information about a user's playing statistics and all the messages the client DRM module sends out are in plain text for easy checking by a user if the client DRM module abides by this rule, consumer privacy is fully protected in our DRM system.