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.