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** Description:** The results of the analysis of the vulnerability of the network to the steganographic channel attack "by a known mathematical model" has been presents in this article.TheDistributions of ISN values in the management of their generation operating systems and steganography has beenanalyzed. Using of the truncated Fourier transform in Galois field for the purchase of a uniform nature of the distribution of the initial sequence number (ISN) which generate by steganographic system has been proposed.

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Keywords:
** network steganography, truncated Fourier transform in Galois field, initial sequence number

Ruban, Y.V., Dudenko, S.V. and Smyrnov, A.A. (2016), “Podkhod k otsenyvanyiu uiazvymosty stehanohrafycheskoho kanala na osnove usechёnnoho preobrazovanyia Fure v pole Halua k atake «po yzvestnoi matematycheskoi modely»” [The approach to the assessment of vulnerability steganographic channel based on the truncated Fourier transform in Galois field to attack "by a known mathematical models"],