High payload steganography mechanism using hybrid edge detector

Keywords: LSB steganography Stego-image Image steganalysis Hybrid edge detection a b s t r a c t Steganography is the art and science of hiding data into information. The secret message is hidden in such a way that no one can apart from the sender or the intended recipient. The least significant bit (LSB) substitution mechanism is the most common steganographic technique for embedding a secret message in an image with high capacity, while the human visual system (HVS) would be unable to notice the hidden message in the cover image. In this paper, besides employing the LSB substitution technique as a fundamental stage, we take advantage of edge detection technique. The experimental results show that the proposed scheme not only achieves high embedding capacity but also enhances the quality of the stego image from the HVS by an edge detection technique. Moreover, based on that the secret message is replaced with different LSBs, our scheme can effectively resist the image steganalysis. In the fields of information hiding, there is a visual requirements model, which is called magic triangle, given in Fig. 1 (Johnson, Duric, & Jajodia, 2001). The first requirement, called capacity or also embedding payload, is determined by the number of secret bits embedded in each cover pixel. A higher capacity allows much more the secret data to be inserted into the cover image. The second requirement, named imperceptibility, is usually calculated by peak signal-to-noise ratio (PSNR). When the difference between the cover image and the stego image is small, the PSNR value is high. Thus, the stego image quality is considered to be good with the imperceptibility is high. The last requirement called robustness which prevents the secret data from being attacked or stolen. Obviously, Fig. 1 is a convenient model for a visual representation of the required trade-offs between the capacity of the embedded data and the robustness to certain attacks, while keeping the perceptual quality of the stego image at an acceptable level. Steganography is a technique which is used to transmit a secret message under the cover of digital media such as images. It first pays much more attention on embedding payload rather than robustness against intentional attacks compared with watermark which is used to protect the copyright. Moreover, imperceptibility, which is the second requirement, is carefully considered in the ste-ganography algorithms. Thus, an effective steganography scheme should not cause any perceptible distortion and …