In the lecture Steganography: Watermarking, Mr. Ho Dac Hung introduces contents such as Terminology, Watermarking Principles, and Watermarking Applications. Download this lecture to see more, please! | Watermarking Ho Dac Hung 1 Contents Introduction Terminology Watermarking Principles Watermarking Applications 2 1. Introduction Both steganography and watermarking describe techniques that are used to imperceptibly convey information by embedding it into the cover-data. 3 1. Introduction Steganography typically relates to covert point-to-point communication between two parties. Thus steganographic methods are usually not robust against modification of the data or have only limited robustness and protect the embedded information against technical modifications. 4 1. Introduction Watermarking on the other hand has the additional notion of resilience against attempts to remove the hidden data. Thus watermarking rather than steganography principles are used whenever the cover-data is available to parties who know the existence of the hidden data and may have an interest removing it. 5 2. Terminology Visible watermarks Imperceptible watermarks 6 3. Watermarking Principles All watermarking methods share the same generic building blocks a watermark embedding system and a watermark recovery system. 7 3. Watermarking Principles Imperceptibility The modifications caused by watermark embedding should be below the perceptible threshold which means that some sort of perceptibility criterion should be used not only to design the watermark but also quantify the distortion. 8 3. Watermarking Principles Redundancy To ensure robustness despite the small allowed changes the watermark information is usually redundantly distributed over many samples of the cover-data thus providing a global robustness. 9 3. Watermarking Principles Keys In general watermarking systems use one or more cryptographically secure keys to ensure security against manipulation and erasure of the watermark. As soon as a watermark can be read by someone the same person may easily destroy it because not only the embedding strategy but also the locations of the watermark are known in this case. 10 4. Watermarking
