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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]

It is said that the best password manager is our brain. This statement makes sense, but sometimes our brain does not cope, we have to use external resources. The number of passwords per user is growing every year: new social networks, new bank accounts, new registrations in various services, accounts on various services (television, music, Internet service providers, etc.). According to the rules of information security, using the same password for different client services is not rational, because if attackers can, for example, choose a password for your email, they will try to apply it to your other applications such as Internet banking and more. Modern man understands that each service needs its own unique password. The password must be strong, contain a certain number of characters, where among the numbers and letters the reliability of the password is increased by special characters and case changes. It's hard to remember. But remembering one password is beyond the power of most of us. Choosing a convenient and reliable password manager is not an easy task. You really have to trust the service. In the end, it is he who will store your confidential information. In this paper, two dozen password managers were tested and eleven were selected, which are the best in terms of functionality, security and convenience. However, each of the well-known managers does not take into account the individual characteristics of users and needs additions according to their needs. Therefore, the creation of software for storing passwords in encrypted form is relevant. Encrypted passwords can be accessed through the one password you need to remember. Such relationship software was created in this paper, taking into account the needs of corporate and private use. [ABSTRACT FROM AUTHOR]

This paper provides implementations of three well-known ciphers – Caesar Cipher, Vigenere Cipher and Hill Cipher in Microsoft Excel. It is shown how the ciphers can be broken by using Brute-force Attack, Frequency Analysis Attack and Known-plaintext Attack. For the purpose of the cryptanalysis the relative occurrence frequencies of the letters and the index of coincidence (κ ) in Bulgarian language are determined. The classical Frequency Analysis Attack is modified using the cross-correlation between frequencies of letters in the natural language and the cipher text. Modular matrix operations in MS Excel are shown. [ABSTRACT FROM AUTHOR]

Block symmetric ciphers are an integral part of modern complex information security systems. Today, the attention of researchers is focused on increasing the efficiency and performance of block symmetric ciphers. However, it is shown by the practical experience of implementation of data encryption systems, that block cipher modes of operation are also of great importance for the efficiency and performance of encryption systems. In this paper we propose new block cipher modes of operation: with block skipping, as well as with block skipping and the use of pseudo-random key sequence generator. The proposed block cipher modes of operation make it possible to reduce the amount of used in the program data encryption operations (i.e. the amount of the block symmetric cipher runs). For the developed block cipher modes of operation, the parameters are calculated to ensure a high level of stochastic quality of the obtained ciphertext, which is confirmed by the tests carried out in accordance with the NIST stochastic test suite. At the same time, it was found that the block cipher mode of operation with skipping of blocks and the use of a pseudo-random key sequence generator, provides a significant increase in the number of information protection levels of the applied cryptographic transformation, and also shows the best results when passing the NIST stochastic tests suite. The developed block cipher modes of operation are a reasonable solution for use in applications running on platforms with limited computing and power resources, primarily on mobile platforms. In this case, it is preferable to select a block cipher mode of operation with skipping of blocks and use of pseudo-random key sequence generator. Note also that the presented block cipher modes of operation allow to combine the advantages of block ciphers and generators of pseudorandom key sequences. [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 paper focuses on new steganographic algorithm development. Proposed algorithm is stable to compression, including high rate compression, and based on singular vectors insensitive of image matrix blocks which corresponding to maximal singular values. Algorithm is polynomial of degree 2. The results of numerical experiments confirm the efficiency of the proposed algorithm. [ABSTRACT FROM AUTHOR]

This paper is devoted to steganalysis algorithm determining presence a secret message embedded into digital image which is stored in compressed or uncompressed form. The algorithm is based on the analysis of pairs of colors and uses the method of modifying the least significant bit. [ABSTRACT FROM AUTHOR]