The Verimatrix Content Authority System, or VCAS, is described by the manufacturer as the first solution of its kind to provide session-based watermarking for IPTV broadcasts. A separate key is used for each user, making it possible to identify the original recipient when content subsequently appears as an illegal copy.
VCAS combines public-key infrastructure, X.509 digital certificates and digital watermarks. Protected content is marked three times: first during production, then at the point of delivery, and finally at the user or purchaser. The watermarks are embedded in the video stream and visible only to machines. They are intended to survive both transcoding and analogue conversion.
