Chapter 4 - Type I (Linear) Data Hiding

Abstract

This chapter investigates the achievable hiding capacities (payload) of type I (linear) data hiding in still images. Most promising data hiding applications—authentication, copyright control, and ownership verification—involve multimedia data and assume the presence of a very powerful attacker. Many of the data hiding techniques that are proposed for such applications are based on type I data hiding. There are two reasons for the popularity of type I methods: simplicity of implementation and robustness to severe additive attacks. Most of the state-of-the-art techniques for data hiding in images utilize some decomposition for embedding the message bits. Currently, the most common image compression tools are the DCT-based JPEG and the subband (wavelet) transform-based source coding techniques of set partitioning in hierarchical trees(SPIHT)/embedded zerotree wavelet (EZW). Adding the signature or the message signal intelligently in the DCT domain can ensure robustness to JPEG compression. Similarly, one could design wavelet-based methods that are robust to SPIHT/EZW compression techniques. It is no surprise that most wavelet-based data hiding methods are very robust to EZW or SPIHT compression, although they are not very robust to JPEG compression. Similarly, DCT-based data hiding methods are robust to JPEG and not so to SPIHT/EZW compression.