Синтез обернених дворозрядових двохоперандних операцій строгого стійкого криптогорафічного кодування. SYNTHESIS OF THE INVERSE TWO-BIT TWO-OPERAND OPERATIONS OF STRONG CRYPTOGRAPHIC ENCODING

Construction the new algorithms of stream and block cipher is inextricably linked with the synthesis of new cryptographic transformation operations. Particular attention deserve the operations that in the process of information transformation on the basis of the subdued sequence provide the achievement of strong cryptographic encoding, which means the maximum uncertainty of the cryptographic transformation results. However, it was paid not enough attention to the synthesis of these operations nowadays, and the processes of constructing the inverse operations of strong cryptographic coding were not studied at all. The purpose of the work is to simulate the inverse two-bit two-operand operations of strong cryptographic transformation for usage in stream and block ciphers. For reaching the purpose, the necessity of using one subdued sequence for direct and inverse transformation was taken into account. An approach that allows synthesizing reverse operations for known direct two- bit two-operand operations of strong cryptographic information transformation, based on the technology of combining single-operand operations of strong cryptographic encoding, is proposed. The entire sequence of mathematical transformations, which provides the synthesis of a formalized operation model suitable for practical application in cryptographic primitives, is considered in the article on the example of one operation’s construction. Synthesized operations are implemented on the software level as well as on the hardware level, which provides an ease of reaching the effect of strong cryptographic encoding. Thus, the research made it possible to develop a model of an inverse two-bit two- operand strong cryptographic transformation. The combination of the obtained inverse transformation with the direct at implementation the method of increasing the stability and reliability of stream encryption will provide maximum uncertainty for the results of cryptographic transformation, regardless of the subdued sequences’ quality.
криптографічне кодування, декодування, обернені операції, криптоперетворення, перестановки, надійність шифрування, строге стійке криптографічне кодування, синтез операцій, cryptographic encryption, decryption, inverse operations, cryptographic transformations, permutations, reliability of encryption, strong cryptographic encoding, synthesis of operations