Cox’s Algorithm: strengths and weaknesses with varying composition digital images

Starting in the early 90’s, numerous digital watermarking schemes were introduced to combat the unauthorised copying of digital multimedia on the web. Initially techniques were proposed which manipulated data in the spatial domain to embed the secret information. However Cox et al. progressed to use a spread spectrum technique, which alters components in the frequency domain of an image to hide the secret data. In this paper Cox’s second-generation watermarking algorithms for embedding and detection are discussed. A number of images are watermarked and then used with a benchmarking tool called Stirmark. This tool performs various attacks on the watermarked images. The results obtained show the strengths and weaknesses of using Cox’s algorithm with varying composition images as a cover media.