The digital information revolution has brought about profound changes in our society and our lives. The many advantages of digital information have also generated new challenges and new opportunities for innovation. This thesis discusses the issues regarding multimedia information hiding and its application to multimedia security and communication, addressing both theoretical and practical aspects, and tackling both design and attack problems. It presents multiple aspects of information hiding with both analytic investigation and experimental results, with emphasis on Steganography and Steganalysis techniques. In the fundamental part, a few key elements of steganography through a layered structure were identified. Information hiding is modeled as a communication problem where the embedded data is the signal to be transmitted. Various embedding mechanisms target different robustness capacity tradeoffs. The study of these tradeoffs was for all the major categories of embedding methods. It provided a platform to investigate the Steganalysis and all its recently introduced methods and branches. One of these branches is the steganography destruction, which was investigated thoroughly, and a new method of steganography destruction was presented. The proposed destruction idea can be viewed as a new approach to the definition of steganographic security. Two new ideas are presented in this thesis, the first is to use the Steganography Firewall to improve the security level for any digital communication medium. It will provide protection from any secrete hidden messages that can possibly embedded in normal digital stream. The second idea is the use of wavelet denoising theory to destroy the steganography messages that possibly embedded in digital medium. All the evidence to prove both ideas was provided. The goal was to protect the communication medium from hidden illegal criminal activities that uses the steganography in public networks. This goal has been achieved and practically the usefulness of the proposed steganography destruction algorithm that can work with the proposed new type of Firewall was proved.The proposed destruction filter is based on considering the stego secrete messages that are embedded inside the cover, as an embedded noise. A lot of denoising algorithms are available, and researchers continue developing new ideas on denoising. All of these ideas are based on wavelet capabilities on denoising. One simple wavelet denoising algorithm was used in this thesis, and it was sufficient to achieve the goal. Various embedding methods targeted different robustness capabilities are used during the testing of the proposed approach. Investigating all the major categories of embedding methods proved that the destruction of stego messages can be achieved on certain level of denoising procedure. It was found that the level-3 wavelet decomposition on the algorithm used in this thesis is quite sufficient to destroy any stego messages embedded on any of the tackled methods. The proposed approach is a promising field of research. With some improvements and practical implementation of the firewall, this approach will open a new horizon in the network security field.