An asymmetric watermarking scheme based on random decomposition in hybrid multi-resolution wavelet domain using 3D Lorenz chaotic system

In this paper, an asymmetric watermarking mechanism based on the random decomposition in hybrid multi-resolution wavelet domain is proposed. To further enhance the security of the watermarking scheme, Lorenz's chaotic system is employed for pixel swap over process. The hybrid multi-resolution wavelets are created by utilizing Walsh transform and the fractional Fourier transform of several orders. These fractional orders along with the Lorenz frameworks parameters and initial conditions broadened the key-space. The proposed mechanism has non-linear characteristics and an enlarged key-space to oppose any brute-force attack. The proposed system is validated on gray-scale images. The principle behind the development of the proposed scheme has been elaborated by carrying out cryptanalysis on system based on the random decomposition. Personal computer based reproductions have been implemented to prove the validity and authenticity of the scheme. Results obtained authenticate that the proposed crypto-system not only offers higher protection against brute force and noise attacks but is also unassailable to special attack.