A Review about Digital Watermarking Technique under Steganography

Steganography comes from a Greek word, which means secret writing or covered. The goal of steganography is to hide messages in such a way that no one apart from the intend recipient even knows that a message has been sent. Steganography is used in various mediums such as text, audio, images etc. watermarking is considered as an important technique in steganography where one image is embedded in another and the two images are related to each other in some way. Today’s world is almost considered as a digital world. Almost every field in this world are digitalized and there is enormous use of digital contents. Information contained in internet and multimedia systems is also in digital form. The copy of contents is not so difficult without quality loss. Digital water marking is the most effective solution to this problem. Digital watermarks are of different type such as robust, fragile, visible and invisible. There are some requirements such as integrity, robustness and complexity.