Implementation of the method of encoding series lengths to provide procedures steganographic image insertion

Abstract

The purpose of this article is to introduce the principle of encoding series lengths to provide inter-block data multiplexing of a hybrid steganoalgorithm. As part of the modeling, it is made the assumption that the attacker has successfully determined one of the two parameters of content processing: the size of the basic blocks (BB) and the implemented principle of series scanning. The modeling was performed on the example of one test halftone image of the «city» type. Samples of the attacked test image obtained for a short sample stack (length in 4 series) are presented. An analysis of the results of attack content when using different ways of smoothing the source images is carried out. The implementation of different smoothing ways allows to improve in the combinatorics of multiplexing series and the number of formed BB. It is emphasized that with an increased dimensionality of the BB, the combinatorics of the multiplex of series parameters is limited. The dimension of the BB and the way of organizing the series scanning are elements of the composite key of the data extractor. The use of the principle of encoding series lengths significantly reduces the computational complexity of the algorithm and creates conditions for the implementation of inter-block multiplexing procedures. It is concluded that the use of the parameter of series lengths destroys the correlation relations of the source data more than in the case of using only BB. The main elements at the stage of inter-block content processing are BB and their parameters of series lengths. The modeling results confirm the key role of the «series length» parameter in the procedure of legitimizing content extraction. The variability of the sampling order of the used parameters of the BB series significantly enhances the resistance of the content to unauthorized extraction attempts. Attention is drawn to the fact that the principle of encoding series lengths is limited in the background areas of images, which makes it possible to preserve highly informative image areas and determine the structure of visual artifacts. According to the modeling results, it is concluded that the use of the method of encoding series lengths in inter-block multiplexing procedures additionally strengthens the protection and complicates the work of the steganoanalyst and determines the further course of the attack.