Copy protection for high-definition baseband video

A copy protection (CP) system is proposed for transmission of high-definition (HD) baseband video signals among consumer electronic (CE) products in the home. An encryption technique adds fluctuating pseudo-random amplitude-offsets to the components of the video signal to be protected, thereby disrupting the entertainment value of intercepted signals. The decryption technique subtracts equivalent offsets regenerated by legitimate receiving devices, thereby restoring the signal. The value of each offset remains constant for the duration of each horizontal scan line so that simple analog voltage summing/differencing circuits can be used for encryption/decryption of analog video signals. The same simple encryption/decryption algorithms can be used for digital implementations to protect digital transmission. Arguments are presented regarding why a CP system for baseband HD video is needed to ensure forward compatible access to premium content by emerging categories of HD-capable CE products. Prototype hardware implementing the analog encryption/decryption techniques has been successfully demonstrated