A. Babash - Dr. Sc. (Phis.-Math.), Professor, Moscow State University of Economics, Statistics and Informatics (MESI)
E. Romanova - Associate Professor, Moscow State University of Economics, Statistics and Informatics (MESI)
A. Aleksandrov Student, Russian State Social University (RSSU)
I. Larionov - Student, Russian State Social University (RSSU)
A. Tarelina - Student, Russian State Social University (RSSU)
E. Tashchilin - Student, Russian State Social University (RSSU)

The paper proposed a method for decrypting the cipher reshuffle. The complexity of the method is less than the total complexity of testing. To evaluate the practical effectiveness of the method developed two applications written in C++, one for message encryption and another for decryption of the received cipher text. For one of the proposed methods, experiments by decrypting the cipher reshuffle. Open and encrypted texts used alphabet of 34 characters - lowercase letters of the Russian alphabet and spaces. Thus, the texts do not contain numbers, and punctuation. Ciphertext lengths: 250, 1000, and 3000 characters. At each of these lengths is known part of the key D = d (the order of substitution) was varied. At each key length d is usually chosen randomly with equal probability and twenty-five keys (permutations of degree d) of the total number of possible keys. In the method used by the decryption probability adjacent pairs of letters of plaintext The experiment revealed the keys in which the plain texts recovered differently: definitely correct, partially correct, not completely, but partly readable, it is not clear the text. To describe the results was introduced following qualitative scale intelligibility partially decrypted message: - good: most of the words and syllables (from 76 to 100%) are clear, the decrypted text gives a fairly complete picture of the meaning and content of the message, minor details of the message clear. - the good: a large part of the words and syllables (66-75%) are clear, the decrypted text gives an idea of the content and meaning of the message, the individual fragments are not clear. - average: about half of words and syllables (46-65%) are clear, the decrypted text gives an idea of the general nature of the text and the main idea or theme of the message. - weak: about a third of all words and syllables (26-45%) are clear, individual decoded fragments give an idea of the individual topics messages, the content and the nature of the message. is not clear. - the bad: only some of the words and syllables understood (0-25%), the decrypted text itself is not connected, illogical and not well understood, clear of the words.