Digital watermarking is a method in which the information is embedded directly and imperceptibly into digital data. Potential applications of digital watermarking include copyright protection and authentication. In this monograph a set of novel and generic watermarking scheme has been developed for colored digital images that can embed a holographic logo or a meaningful text. The general watermarking mechanism has been discussed in chapter 1, and a review of algorithms in chapter 2. The colored image watermarking using DCT transformation has been coined in chapter 3. The technique acts as a model for watermarking colored images. The model is advanced and an edge sensitive algorithm is discussed in chapter 4. This algorithm embeds watermark only in sensitive areas of the image thus securing the actual concerned content of the image. The algorithm has been sophisticated further with the incorporation of chaotic system in chapter 5. The algorithm used chaotic dynamical system for determining the strength factor for incorporation of watermark thereby addressing Kerckhoffs'' principle. Finally, chapter 6 provides the nutshell of the work.