Spatial-spectral Watermarking Scheme for Jpeg Steganography

Steganography is the art of concealing the presence of a communication, across an open channel, from undesired parties. This is achieved by the encoding of message data in innocuous cover objects, such as JPEG digital images. Many JPEG steganography algorithms exist; most perform the encoding in the spectral domain of the image. A new steganographic method, deemed the Spatial-Spectral Watermarking Scheme (SSWS), has been developed and utilises both the spatial and the spectral domains for the encoding process. A developed mathematical model of the scheme predicts a maximum gain in terms of steganographic capacity of 4.9 over an existing algorithm, JSteg. Experimental data obtained from a software prototype confirms this result. Furthermore, the experimental data confirms that the securities in the spatial domain and the spectral domain are inversely proportional to the information amounts embedded in these two domains.