NONLINEAR THREE-DIMENSIONAL MULTI-ROUND DATA TRANSFORMATION METHOD Russian patent published in 2019 - IPC H04L9/06 G06F7/58 

FIELD: computer equipment.

SUBSTANCE: invention relates to the field of computer equipment. Disclosed is the non-linear three-dimensional multi-round data transformation method, which includes the input, output data blocks, all intermediate conversion results representation in the form of a cubic array; sequence of round keys K₁, K₂, K₃ generation from the source key; the layer (Layer) concept introduction; by the input block M with the 512 bits capacity the data block S of the same capacity generation in accordance with the S:=M expression, then three rounds of conversion performance along the x, y, z axes, respectively; each i-th round key K_i (i=1, 2, 3) division by round sub-keys; each layer stochastic transformation (MixLayer) along the x axis, the converted layers combination into the converted block S in the first round; each layer stochastic transformation (MixLayer) along the y axis, the converted layers combination into the converted block S in the second round; each layer stochastic transformation (MixLayer) along the z axis, the converted layers combination into the converted block S in the third round; at that, all the data blocks are represented as the 8×8×8 bits cubic array; the layer (MixLayer) conversion (mixing) operations are implemented in the form of n iterations, and the number of n iterations should ensure the information complete dispersion and mixing; during the first round conversions performance, the data block S is divided into eight layers S_x0, S_x1, …, S_x7 along the x axis; each layer S_xk, k=0, 1, …, 7, is conventionally represented as the 8×8 bits square array, after which it is subjected to the MixLayer conversion, then the converted layers are combined into the converted block S; during the second round conversions performance, the data block S is divided into eight layers S_y0, S_y1, …, S_y7 along the y axis; each layer S_yk, k=0, 1, …, 7, is conventionally represented as the 8×8 bits square array, after which it is subjected to the MixLayer conversion, then the converted layers are combined into the converted block S; during the third round conversions performance, the data block S is divided into eight layers S_z0, S_z1, …, S_z7 along the z axis; each layer S_zk, k=0, 1, …, 7, is conventionally represented as the 8×8 bits square array, after which it is subjected to the MixLayer conversion, then the converted layers are combined into the converted block S; a secret replacements table with the 4×8×256 dimension (in the case of four 8-bit S-blocks) or 8×4×16 (in case of using eight 4-bit 5-blocks) is selected; each i-th round key K_i (i=1, 2, 3) is divided into eight round sub-keys K_i0, K_i1, …, K_i7, each with the L_RK×n bits capacity; where K_ik=K_ik0 || K_ik1 || … || K_ik(n-1), |K_ikj|=L_RK, i=1, 2, 3, k=0, 1, …, 7; L_RK – is the original basic stochastic conversion round key capacity); each k-th K_ik subkey is used for the corresponding k-th layer conversion in the i-th round (layer S_ik); each j-th subkey K_ikj is used in the j-th iteration (j=0, 1, …, (n-1)) of the corresponding k-th layer conversion in the i-th round.

EFFECT: technical result is increase in the nonlinear multi-round data conversion cryptographic strength and speed.

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