Fast and near optimal parity assignment in palette images with enhanced CPT scheme

Abstract

In the area of palette image steganography, by Parity Assignment approach, we introduce two fast and near Optimal Parity Assignment (nOPA) methods. The first is called rho-method which does not take any reorder procedures on color space of palettes. The second is called for-loop method which is the fastest and simplest one. The experimental results on 1000 palette images randomly selected show that this algorithm runs faster than the algorithms in OPA approach, while the costs (of changing colors) of two methods are equal. Comparison of the rho-, for-loop and EzStego methods with the OPA method is presented which shows the advantages of the two nOPA methods over the third. Among these the rho- method is the best, and the costs of the rho- and OPA method are equal. To prevent steganalysis, base on our nOPA methods, we propose a practical scheme by an enhanced CPT scheme for palette images. © 2010 Springer-Verlag Berlin Heidelberg.