Basic Characteristics of Watermarking

The issue of robustness is extremely important for watermarking. Robustness is a technical term that simply means that a digital watermark should be able to withstand a large number of different physical and geometric distortions, both intentional (e.g., malicious attacks) or unintentional (e.g., image compression, scanning vs. copying, noise contamination, dimensional changes, etc.). After these manipulations, the robust watermarking algorithm should still be able to extract the embedded watermark or prove the existence of the watermark from the watermarked image. Without all the knowledge about watermarking, it should be very difficult to forge the copyright protection mark of a data product. If an attacker attempts to remove the watermark it will result in the complete destruction of the multimedia product. Assuming that a patron downloads a work published by a digital library online, prints it out, and illegally distributes it in large numbers for profit, the work containing the watermark should provide sufficient evidence of copyright despite physical distortion.