Implementation of Robust and Secure Watermarking Algorithm on FPGA using DCT

Digital watermarking deals with embedding digital content in a cover signal so that it becomes indiscernible to make it robust against different security threats. This work demonstrates the implementation of a robust and secure watermarking technique on a Field Programmable Gate Array (FPGA) using Discrete Cosine Transform (DCT). Block by block DCT of the cover image was computed and watermark pixels in each of the blocks were hidden using middle-frequency band coefficients. Security is ensured by encrypting the watermarkwith a secret key and Arnold transform. The resultant watermark image is robust to various threats like JPEG compression, scaling, cropping, and noise attacks. This watermarking approach requires a large amount of data to be processed at high speed. FPGA is the best choice for such an application. Also, it is reprogrammable and easily upgradable according to user application. In this work, a watermarking algorithm is implemented using Xilinx design tools on the Artix-7 FPGA board.