High capacity secret image sharing using multilayer image steganography with primary cover predictive error

Abstract

Image steganography is the art of hiding secret message in greyscale or cover images. Easy detection of secret message for any state-of-art image steganography can break the stego system. To prevent the breakdown of the stego system two tier data hiding is used. In this paper, we propose a high capacity image steganography with greyscale primary cover. Predictive primary cover PPC is computed from the primary cover using median edge detector MED predictor. Predictive error PE is the difference between primary cover and the PPC. The high level bit planes of the secret image payload are X-ORed with low level bit planes of the PPC and vice-verse. The resulting Stego image is embedded in a secondary cover image using bit plane X-OR algorithm. The cover image used is an RGB colour image. The proposed steganography scheme enhances the level of security of the existing bit plane X-OR algorithm without considerably increasing the computation time and detectability. The experimental results show that the proposed scheme achieves higher level of security with high embedding capacity. Higher level of security achieved by the proposed multilayer steganography scheme enhances the performance and security of the bit plane X-OR algorithm.