A DRM System Supporting What You See Is What You Pay

We present a Digital Rights Management (DRM) system that supports what you see is what you pay. In our system, multimedia is compressed with a scalable codec and encrypted preserving the scalable granularity and multiaccess capability. This paper focuses on the DRM modules enabling efficient key generation and management. We employ a light license server which stores only the master keys of content publishers, which are used to regenerate decryption keys for clients during license acquisition. All the remaining information needed in key generation is efficiently packaged in a DRM header of protected content. The DRM header is sent to a license server during license acquisition to allow the license server to generate a single key for a requested access, which is sent to the client in a license along with the acquired rights. The key is used by the client to generate all the remaining keys of subordinate accesses.