I. Introduction
The digital information revolution has brought many changes to our society and to our everyday lives. The power of software and digital devices (e.g. digital cameras, speech recorders, audio players, etc.) has facilitated the tampering of images, and audio and video recordings. These modifications are made in the content, causing it to have a meaning that is different to the original. Consequently, the integrity and authentication of digital media is infringed by these attacks. Digital watermarking is one possible solution to this problem [1]. Digital watermarking schemes insert a watermark into a host signal in such a way that it is imperceptible to the human observer but can be recovered using an extraction algorithm.