Data Hiding and applications

Rapid evolution of digital technology has improved the ease of access to digital information enabling reliable, faster, and efficient storage, transfer, and processing of digital data. It also has lead to the consequence of making the illegal production and redistribution of digital media easy and undetectable. Hence, the risk of copyright violation of multimedia data has increased due to the enormous growth of computer networks that provide fast and error-free transmission of any unauthorized duplicate and possibly manipulated copies of multimedia information. One possible solution may be to embed a secondary signal or pattern into the image that is not perceivable and is mixed so well with the original digital data that it is inseparable and remains br>unaffected with any kind of multimedia signal processing. This embedded secondary information is a digital watermark which is, in general, a visible or invisible identification code that may contain some information about the intended recipient, the lawful owner or author of the original data in the form of textual data or image. In order to be effective for copyright protection, the digital watermark must be robust, which means that it is difficult to be removed from the object in which it is embedded despite a variety of possible attacks. Several types of watermarking methods have been developed so far; each of which has its own advantages and limitations.