a device receives protected content and a license for the content , unprotects the content using an input key and retrieves a rule associated with the input key . the device then processes the content to create new content , retrieves at least one output key associated with the input key in the retrieved rule , protects the content using the output key and sends the newly protected content and the corresponding license . it is thus possible to impose a work flow as it is necessary for a device to store a particular key in order to access the content and as the rule imposes a particular output key depending on the input key . in a preferred embodiment , the content is scrambled using a symmetrical key that is encrypted by an asymmetrical key in the license . an alternate embodiment uses watermarking techniques instead of encryption . the invention finds particular use in video processing .