DOI: 10.7256/2409-7543.2016.6.21252

Abstract: The research subject is the steganographic methods of information protection. There are two key ways to protect information – cryptographic and steganographic. Cryptographic methods conceal only the contents of the transmitted information. At that, the fact of transmission of the codified data can draw the attention of an intruder who can use the successful cryptographic attacks, aimed at the loss of confidentiality. Steganographic methods hide not only the contents of the information sent, but also the very fact of sending. Steganography and cryptography are complementary methods, which, used together, can significantly increase the safety of the transmitted data. Therefore, it is necessary to develop not only cryptographic, but also steganographic methods of data protection, which should be resistant to the detection of the process of sending. The research methodology contains the passive methods of analysis of detection of the information, embedded in the image, including statistical and visual methods. The novelty of the study consists in the development of the steganographic system of data protection on the base of the proposed original algorithm of embedding the information by the coverage of the image block in lines and columns. The authors demonstrate that this steganographic system maintains its resistance to passive steganoanalytic attacks when the blocks up to 24x24 pixels are covered, and with this coverage degree it is more resistant than the standard and the advanced steganographic methods based on the direct spectrum broadening. 

DOI: 10.7256/2409-7543.2016.6.21337

Abstract: The research subject is the steganographic methods of data protection, able to hide not only the contents of the transmitted information, but also the very fact of transmission. The authors consider an important problem of creation of steganographic systems of information protection – the high secrecy of information transmission, which is the most important characteristic of such systems. The secrecy is understood not only as a visual or sound indistinguishability of a digital media file from the media file with embedded information, but also the statistical indistinguishability. The research methodology is based on the objective metric of image distortion, including the generally accepted figure – peak signal to noise ratio. The scientific novelty of the study consists in the proposed method of increase of the hidden transmission of information using the minimal possible image distortion with its maximal filling with embedded data. The authors analyze the most widely used steganographic systems of information protection. The authors ascertain that the most promising method of steganography is the method of direct spectrum broadening, since it has particular advantages compared with other methods. The problem of a high level of secrecy of information transmission, connected with the unacceptably high level of a container distortion upon the hidden data embedding is solved using this method. Based on the peak signal to noise ratio, the authors study the distortion of digital images with hidden information, embedded using different methods. The proposed method demonstrates the best results. 

DOI: 10.7256/2306-4196.2016.6.21398

Abstract: The subject of the research is the steganographic information protection system (SIPS) based on the method of the direct spectrum spread with minimum change of image pixels and maximum image fill. Special attention is paid to the problem of creating a SIPS with a blind decoder because the original image strongly influences the correct extraction of in-built information. The authors examine such aspects of the topic as the application of the autoregression process and error-correcting codes in order to reduce the number of errors during extraction of in-built information. The methodological basis of the research involves methods from the theory of noise-resistant coding, methods of digital image processing, and methods of mathematical statistics. The novelty of the research is caused by the fact that the author defines the optimum block size (32x32 pixels) that enables the two-dimensional autoregression process (AP) to provide the maximum number of correctly extracted in-built bits. Moreover, the authors analyze efficiency of applying BCH Code, Reed-Solomon code and LDPC code for restoration of in-built data. They demonstrate that LDPC code combined with the algorithm of 'soft' decision making 'Belief propagation' option is the most efficient for reducing the number of errors when extracting in-built information by the stenographic method on the basis of the direct spectrum spread.