i need matlab code for digital watermarking using fft

Embedding a hidden stream of bits in a file is called Digital Watermarking. The file could be
an image, audio, video or text. Nowadays, digital watermarking has many applications such
as broadcast monitoring, owner identification, proof of ownership, transaction tracking,
content authentication, copy control, device control, and file reconstruction (Cox et. al., 2008).
In literature, the host file is called the “asset”, and the bit stream is called the “message”. The
main specifications of a watermarking system are: Robustness (Against intentional attacks
or unintentional ones such as compression), Imperceptibility, and Capacity. Importance of
each depends on the application. As a matter of fact there is a trade-off between these factors
(Barni & Bartolini, 2004). Although watermarking in some literature includes visible
imprints, here we only mean the invisible embedding of the data.
In this chapter, we will introduce how to use MATLAB to implement image watermarking
algorithms. These algorithms include the most famous ones which are widely used in
current literature or more complicated approaches are based upon. These are commonly
divided into three categories (Barni & Bartolini, 2004)
1. Watermarking in Spatial Domain
2. Watermarking in Spectral Domain
3. Watermarking in Hybrid Domain
In section 2 we will go through some basic image processing commands in MATLAB.
Section 3 provides information about different fundamental watermarking methods.
Evaluating the algorithms is discussed in Section 4, and finally section 5 brings a conclusion.