Different Crypto - Watermarking Techniques

Digital image watermarking is a technology that has made to protect digital images from illicit manipulations. Digital watermarking is a concept intimately related to steganography, in that they both hide a message inside a digital signal. Watermarking tries to hide a message related to the actual content of the digital signal, but in steganography the digital signal has no relation to the message, and it is used as a cover to hide its existence. Watermarking is used for providing a kind of security for various types of data. It may be image, audio, video, etc. Watermarking is different to steganography; it has the extra requirement of robustness against possible attacks. Using digital watermarking, copyright information can be implanted into the multimedia data. This is implemented by using algorithms. Information such as image, number or text with special implication can be embedded. The purpose of this can be for copyright protection, covert communication, authenticity distinguish of data file, etc.