Enhanced payload and trade-off for image steganography via a novel pixel digits alteration

Abstract

Many high capacity image steganography algorithms have been proposed but at the cost of lower imperceptibility. To fill the gap, this paper proposes a novel RGB image steganography technique that not only enhances the hiding capacity but also largely improves the trade-off between capacity and imperceptibility on maximum embedding rate. The technique encrypts the secret data (text, grayscale or a color image) into a sequence of two-digit decimal values. A digit in the sequence is hidden in a cover pixel by altering the pixel’s digits to the nearest pixel value possible. Most common spatial hiding techniques are the Least Significant Bit (LSB) substitution and Pixel Value Differencing (PVD) which hide data in the form of bits. The proposed linear time digit based hiding technique outperforms LSB substitution, PVD or their variants in terms of both capacity and imperceptibility. It also outperforms the existing digit hiding methods in color images. Moreover, the method is secure against the two detection schemes of Weighted Stego-Image steganalysis.