Chaos Applications in Digital Watermarking

Abstract

To protect copyrights of multi-media products effectively, we focus on the topic of chaos applications in digital watermarking. Digital watermarking algorithms in digital images or video based on chaos and other techniques were proposed. The experiments results show that the proposed algorithms keep the quality of the image or video well and are robust enough to various attacking. Especially, the security performance of the watermarking algorithms is improved a lot after chaos is employed. This chapter is organized as follows. In Sect. 8.1, we present two chaos-based robust image watermarking schemes. The first one is chaos-based image spatial domain watermarking, and the other is chaos-based image discrete wavelet transform (DWT) domain robust digital watermarking. In these robust image watermarking schemes, discrete chaotic maps are adopted to scramble the watermarks or for selecting watermarks embedding positions. In Sect. 8.2, chaos-based fragile and semi-fragile image watermarking algorithms are presented, respectively. Chaotic maps are used to generate the chaotic fragile watermark image or the semi-fragile binary pseudo-random watermark sequence. The fragile and semi-fragile image watermarking techniques can be used for image authentication or image malicious tamper detection. In Sect. 8.3, a chaos-based multipurpose image watermarking technique is described, which can be applied to image authentication and copyright protection simultaneously. Finally, a digital video watermarking algorithm based on chaos and motion vector is presented in Sect. 8.4, which can be applied to protect video products copyright.

Digital watermarking is a branch of information hiding which is used to hide proprietary information in digital media, such as image, video, text and so on. In some applications, the sensitive digital media related to politics or commerce, such as military maps, medical images or multi-resolution images, should be protected in order to avoid unauthorized users knowing it. A digital watermark is a visible, or preferably invisible, identification code that is permanently embedded in digital media, to prove owner authentication thereby providing a level of document protection.

In recent years, chaotic maps have been used for digital watermarking, to increase the security. The most attractive features of chaos in information hiding are its extreme sensitivity to initial conditions and the outspreading of orbits over the entire space [1]. These special characteristics make chaotic maps excellent candidates for watermarking and encryption, based on the classic Shannon’s requirement of confusion and diffusion [2].

Generally speaking, chaos applications in digital watermarking include: to generate the watermarks, for encrypting watermark images, for selecting the embedding places in image watermarking, for watermark embedding and watermark extraction.