1. A method of processing digital content, the method comprising the steps, in a device comprising a processor, of: receiving a content scrambled using a control word; receiving, via a user interface, a user identifier and a user code; processing the user identifier and the user code to obtain the control word; descrambling the scrambled content using the control word; inserting into the descrambled content a watermark based on the user identifier; and outputting the watermarked content.