Abstract: The article consideres the accuracy of the steganoanalysis using the Weighted Stego algorithm in passive data transmission channel countermeasures using the method of embedding the spatial region of fixed digital images with the RGB color model into the smallest significant bit. The dependence of the accuracy of steganoanalysis by the Weighted Stego method on the fraction of a homogeneous background in the analyzed image was studied. The drop in the accuracy of pixel prediction in the background areas of the image is investigated using the prediction model proposed by the authors of the original Weighted Stego algorithm. The Weighted Stego steganoanalysis algorithm is investigated. The basis for the steganoanalysis algorithm is a model for predicting the pixel values of the analyzed image from adjacent pixels. To assess the effectiveness of the analysis, the BOWS2 collection was used. Embedding information is realized by changing the least significant bits of the image in the spatial domain with a payload of 3-5 %%. The effectiveness of the methods is determined taking into account the obtained truly positive, truly negative, false positive and false negative values of the classification of images. The fall in the accuracy of steganoanalysis by the Weighted Stego method is shown with an increase in the fraction of a homogeneous background in the analyzed image. The method of improvement of the pixel prediction model in the basis of Weighted Stego is proposed, which allows to level out the drop in accuracy with increasing the fraction of a homogeneous background in the analyzed image. The results of the work are useful to a specialist in the field of information protection in the tasks of detecting and countering a hidden data channel. The obtained results can be used in the development of steganoanalysis systems based on the Weighted Stego algorithm.

Abstract: The article deals with the stability of the digital watermark built-into the image-container through the use of steganography algorithms based on discrete wavelet transform (DWT), to external influences, such as JPEG lossy compression, filtering, noise and scaling. The author states that steganographic algorithms performing embedding can provide good secrecy of the digital watermarking, and tend to use the coefficients of correlation property between different planes of one subband having the same coordinates. It is noted that an important parameter when using steganographic algorithms based on the DWT is the choice of the level of wavelet decomposition. The authors describe the methodology which was used to assess the sustainability of the digital watermarking to to external influences on the image-container and experimental conditions. The authors also evaluated stability of DWT ti JPEF lossy compression, to Gaussian white noise, to scale the image to the image filtering. In conclusion the authors say that the results of DWT stability to external influences on the image-container confirm the theoretical advantage of using low-frequency plane wavelet decomposition in steganographic systems with high demands on DWT sustainability.