Digital watermarking algorithms for multimedia data

Nowadays, the remarkable growth of Internet technology makes multimedia applications popular. However, the security issue of multimedia data is a big concern due to the openness of the Internet. The threats may occur in terms of illegal copying and/or unauthorized manipulation of multimedia data. From the last few decades, digital watermarking has been considered as one of the promising solutions for controlling the content from unlawful manipulation and redistribution. In watermarking, a watermark or logo is embedded in the original image. The watermark can be extracted later for applications such as copyright protection, ownership verification, content authentication, and so on. In this context, the watermarking is addressing broadly into two application areas such as copyright protection using robust watermarking and to detect illegal content manipulation through fragile watermarking approach. One more type of watermarking, called semi-fragile watermarking, is also quite popular. It is sustainable against certain attacks for the purpose of copyright protection and is applicable for reinforcing the authentication property of multimedia documents. So, the aim of this chapter is to discuss watermarking approaches such as robust, fragile, and semi-fragile in the context of basic requirements or principles, and developing procedures. We also discuss the state-of-the-art as well as some possible research scope in this particular area.