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Steganography methods are considered to be one of the most common technologies for the protection of any digital data when transmitted over open communication channels at a given time. The solution of the problem of digital data protection using steganography methods is used not only by government services, but also by terrorist organizations. Therefore, the need for research, development and continuous improvement of steganoanalytical methods is becoming extremely important. The steganoanalytical algorithm based on the study of the singular decomposition of digital image matrix blocks is proposed in the paper. The main purpose of this paper is to increase the efficiency of digital image steganoanalysis, in the absence of a container, by developing a new steganoanalytical algorithm based on the study of the singular decomposition of digital image matrix blocks. As a result of a detailed study of the steganography algorithm using the singular decomposition of digital image matrix blocks, the statistical characteristics of the singular values of image matrix blocks are established. Based on the defined characteristics, the paper presents the main steps of the stegananoanalytical algorithm. As a criterion for assessing the effectiveness of the developed steganoanalytical algorithm, the probability of detecting additional information was used. Errors of the first and second type are considered. To compare the results of the developed steganoanalytical algorithm with existing algorithms in open access, the following applications are selected: XSteg; StegSpy. The software product "StegoAnalysis" has been implemented for the automated solution of the stegananalytical problem for digital image. [ABSTRACT FROM AUTHOR]

The protection of electronic information by cryptographic and steganographic methods, as well as their combination, is in great demand today. However, the new type of steganography - hash-steganography, fundamentally differs from classical steganography in that there is no need to embed messages in a container, no need to worry about the amount of information that can be transmitted in one container without compromising the visual stability of the image. A certain sequence of ordinary digital images is a message. The purpose of this work is to increase the efficiency of transmitting a secret message by modifying the hash-method of steganography. Previously, algorithms for obtaining hash functions of digital images have not been used to transmit messages, but they have found their application in hash-steganography. This paper compares two algorithms for obtaining hash codes and suggests a method of their application for transforming a text message into a sequence of digital images. It is a certain order of files transferred that is decisive in the decryption of a message. The symbols of the message are put in correspondence with the part of the hash code of the digital image. Thus, the necessary combination of files is formed, the number of which is equal to the number of symbols in the message. A comparative analysis of the two algorithms of the method has been performed. The results obtained have confirmed the effectiveness of the hash code algorithm based on the analysis of digital image DCT coefficients. This algorithm makes the method resistant to attack by compression, changing brightness and contrast, magnification and rotation. [ABSTRACT FROM AUTHOR]

The use of the digital images in modern society is very common, making it difficult to name an industry where digital images are not used. However, in certain situations, the digital images may be direct or indirect digital evidence, such as in court cases. Tampering or violating the integrity of the digital images is one of the important issues in the information protection. The issue of the digital signal authentication by cybersecurity experts is a pressing issue in the present days. Therefore, the development of methods and algorithms for detecting the integrity of digital signals in general, and digital images in particular, is a very crucial task. Among all the possible variations in the integrity violation of digital images can be distinguished a separate group, in which the digital images are processed by various filters editors, such as blurring, sharpening, etc. The blurring is often applied to images not only when they are tampered, but also as a steganographic attack. Blur detection indicates the inability to use a digital image as the evidence of anything. One of the most effective blur detection methods known from the open sources is a method based on the analysis of singular values of blocks of a digital image matrix. The aim of this paper is to increase the efficiency of the blur detection in a digital image by modifying an algorithm based on the analysis of singular values. Computational experiments are performed to determine the number of parameters to be verified. The results obtained allow modifying the algorithm of the method of the blur detection in a digital image. The modification makes it possible to detect tampered access to a digital image. The modified algorithm is no less effective than the original algorithm, and allows analyzing fewer parameters in a shorter time. The computational complexity of the algorithm is determined by the second order polynomial that is acceptable in terms of the practical application. [ABSTRACT FROM AUTHOR]