What is Tampering Location

Since the beginning of 1990s, some multimedia standards (Joan, Didier, & Chad, 2003) related to image compression, video compression, or audio compression have been published and widely used. These compression methods reduce media data’s volumes, and save the storage space or transmission bandwidth. After the middle of 1990s, network technology has been rapidly developed and widely spread, which increases the network bandwidth. With the development of network technology and multimedia (image, audio, video, etc.) technology, multimedia data are used more and more widely. In some applications related to politics, economics, militaries, entertainment, or education, multimedia content security becomes important and urgent. Some sensitive data need to be protected against unauthorized users. For example, only the customers paying for a TV program can watch the program online, while other customers cannot watch the content, only the administrator can update (delete, insert, copy, etc.) the TV program in the database, while others cannot modify the content, the TV program released over Internet can be traced, and so forth. Multimedia content protection technology protects multimedia data against the threats coming from unauthorized users, especially in network environment. Generally, protected properties include the confidentiality, integrity, ownership, and so forth. The confidentiality defines that only the authorized users can access the multimedia content, while others cannot know multimedia content. The integrity tells whether media data are modified or not. The ownership shows media data’s owner information that is used to authenticate or trace the distributor. During the past decade, various technologies have been proposed to protect media data, which are introduced in this chapter. Additionally, the threats to multimedia data are presented, the existing protection methods are compared, and some future trends are proposed.