PHYSICAL CONTENT OF COMPUTER STEGANOGRAPHY

Abstract

Introduction. The development of computer technology has given a new impetus to the use of computer steganography. However, it is important to understand the physical content of this type of steganography.Purpose. The work aims to describe the practical use and physical content of the phenomenon of computer steganography, the results of the study on the hiding of files in the stegocontainer.Results. Describes the main ns currently computer steganography methods are actively used to solve the following tasks: Protection of confidential information from unauthorized access, overcoming monitoring and management of net-work resources, software camouflage, copyright protection, which is manifested in the use of digital watermarks, is one of the most promising areas of computer steganography. Among the methods of hiding information in images, the most common is the category of algorithms using the lower bits of the image data. They are considered in this paper. These algorithms are based on the fact that in some file formats, the lower bits of the values, although present in the file, but do not affect a person's perception of sound or image. The steganographic software S-Tools was chosen for the study. We created two test monotonous images with the size of 50 × 50 pixels in 24-bit bmp format to analyze the peculiarities of the placement of stego-data in container files. We chose black and white images for the study. A text file was hidden in each of the images, after which the reverse action was performed - extracting the file. As a result of hiding, two stego files were obtained. The paper compared the binary content of the original images and files containing private data. For comparison, the binary content of the black square image and the contents of the stegocontainer with a latent text file are given. Note that the contents of the container and the stego file are only partially listed, but the addresses of the memory cells have selected accordingly. The right column shows the contents of the memory cells in hexadecimal format. The bytes that display the colour of the square are set to "00" because the original image contains only black. We noted that the contents of the cells responsible for the image changed after hiding additional data (this reflected by cells with values of "01"). The paper also describes the procedure for hiding a group of different types of files. During the study, we found that the image file (1920 × 1080 pixels) with a volume of 6,220,854 bytes can hide 777,584 bytes of information.Conclusion. When using steganography, the program uses some algorithms that hide confidential data among the contents of the container: bits of the hidden file replace the bits of the original file at random positions. Thus, the size of the source file and the container file (containing the attached information) is the same, even if you hide a different number of files or different amounts of data.