Real-time video authentication is a major concern for surveillance video cameras. In this thesis, we present a secure, low power and low hardware video watermarking system that inserts an invisible semi-fragile watermark into the video stream for real-time surveillance video authentication during the commonly used MPEG-4 encoding process with insignificant video quality degradation. Our watermarking system was prototyped on an Altera® Cyclone FPGA device and was evaluated to ensure the achievement of high processing speed, low power and low hardware goals. In addition, we propose a general threat model for video watermarking system intended for real-time surveillance video authentication. Grain – 128a, a secure stream cipher, was chosen as a source of low hardware cryptographically secure pseudorandom number generator to generate a secure watermark sequence. The system was also assessed based on different recognized watermarking attacks and the proposed threat model to provide evidence for the achievement of the security goals.