The data hiding approach refers to a method of embedding secondary data into the primary multimedia sources. This is carried out mainly to fulfill authentication and tampering detection, copyright protection and distribution control. The idea of hiding information has a long history, likely to date back a couple of thousand years. In recent decades, techniques of adding some imperceptible data to multimedia sources received special attention from the research community. This many methods of data hiding developed into multimedia security applications in. Most of them are referred to as digital watermarking or Hash marks.
The main advantage of data hiding compared to digital signatures is that it gives the ability to associate the secondary data with the primary media in a seamless way. They are mostly imperceptible and travel with the host image. The data hiding approach can be divided further in several fields. Digital watermarking is the most popular one.