I.N. Vorfolomeev - Staff, Academy of Federal Security Guard Service of the Russian Federation (Orel) I.N. Molchanov - Ph.D. (Eng.), Staff, Academy of Federal Security Guard Service of the Russian Federation (Orel) S.V. Ovsyankin - Ph.D. (Eng.), Staff, Academy of Federal Security Guard Service of the Russian Federation (Orel) E-mail: interleaver@mail.ru V.O. Yudin - Staff, Academy of Federal Security Guard Service of the Russian Federation (Orel)

The paper is devoted to the investigation of different methods of recovering parity check matrix from intercepted bitsteam received from binary symmetric channel. There are a few methods of recovering parity check matrix modern correcting codes: algebraic, statistic, spectral, decomposition of the cofactors. But they are have the disadvantage - hard constraints to the number of errors in the bitstream. The method of parity check matrix recognition [1] has not the above disadvantage. The modified method is aimed to reduce the number of corrupted codewords due to using algorithm of belief propagation. The simulation on the modern correction codes such as LDPC and convolutional codes is presented. The proposed modified method ensures enhanced effectiveness of recovering parity check matrix from intercepted bitsteam.

 

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