Digital Image Watermarking: Challenges and Approach for a Robust Algorithm

This paper presents the challenges for a robust digital image watermarking algorithm. Need for copyright protection in digital media has led to enormous growth in the field of Digital Image Watermarking whereby researchers are striving to come up with new ways of content protection. Recent developments in the field of watermarking though have provided new ways of protecting data yet there are many factors which need to be addressed such that the algorithm of embedding/ extracting a watermark is robust enough to meet these challenges. Robustness can be defined as resilience for a watermark to remain unaffected even when digital content is passed through various processes and attacks and hence increase security, capacity, and imperceptibility of watermarked data. The paper begins with a brief introduction to cryptography and Steganography, which is the platform for a number of digital watermarking concepts. Then, requirements for watermarking systems are discussed along with methods to watermark data efficiently and their strengths and weaknesses. In conclusion there is a new method proposed which uses a concept of nested watermarks using Discrete Wavelet Transform for binary images and Cryptography using Spread Spectrum technique and is supposed to be robust enough to cater to challenges presented here.