D.P. Bessonov, V.G. Dovbnya
Digital steganography is the most promising direction in the field of information protection. In recent years, the attention of specialists in the field of effective coding attracted to the compression of images with the use of wavelet-conversion. In this direction active research and has already received the first results, showing the effectiveness of the application of wavelet transform for image compression. Has developed a number of compression algorithms with use of this transformation.
The main advantage of steganographic methods based on the expansion of the spectrum is the relatively high resistance to various kinds of attacks on the image, because the hidden information is distributed in a wide frequency band and its difficult to remove without the complete destruction of the container. When compressing, alignment contrast, noise removal, and other types of digital image processing, the greatest values of the coefficients are often not subject to change, in contrast to those who have normal close to zero. It is for this reason to hide information necessary precisely in the most energetically securities wavelet-coefficients.
The reverse transformation should take into account that the image was intercepted or subjected to processing of a third party. This could lead to the fact that the spectrum of the image was partially changed, and it is necessary to take into consideration only the most significant wavelet coefficients. In the future, consistently producing the lowest bit of wavelet-coefficient of each graphic components it is possible to synthesize the original hidden message. This approach also allows you to optionally hide the implementation of the wavelet-spectrum image both on the visual, as well as from computer analysis.