Ab s t r a c t. Based on the analysis of a group of two-bit two-operand operations of strict stable cryptographic coding, the relations between direct and inverse operations are established and formalized and their correctness is proved. Applying the technology of combining single-operand strict rigorous cryptographic coding into two-operand operations and using established interconnections, we propose a method of synthesis of inverse operations for known direct operations. This method provides the construction of the inverse operation by converting the second operand of two-bit two-operand operations of strict stable cryptographic coding. The article examines the entire sequence of mathematical transformations that provides the synthesis of a formalized operation model, suitable for practical application in crypto primitives, by constructing models of the relationships between operations and the synthesis of a reverse operation model. The synthesized operations are implemented both at the software and hardware levels and provide the ease of achieving the effect of strictly stable cryptographic coding. K e ywor d s : cryptographic coding; decoding; inverse operations; cryptocurrencies; permutations; encryption reliability; strict stable cryptographic coding; operation synthesis; second operand. Rudnitsky V., Berdibayev R., Breus R., Lada N., Pustovit M., 2019