In one embodiment, a system includes a Headend apparatus including a watermark processor to generate secondary video streams from sections of a primary video stream, group the secondary video streams in groups of at least two secondary video streams, the secondary video streams including units of data for use in watermarking across cryptoperiods in an end-user device which selects one secondary video stream in each group for rendering as part of a composited video stream in order to embed units of data of an identification in the composited video stream, wherein in each cryptoperiod, the watermark processor is operative to generate different groups of the secondary video streams from different non-overlapping portions of the primary video stream, and an encryption processor to generate control words, encrypt each secondary video stream with a different control word, and change the control word of each secondary video stream every cryptoperiod.