UA140087U - METHOD OF CRYPTOGRAPHIC TRANSFORMATION OF INFORMATION - Google Patents

Abstract

The method of cryptographic transformation of information is that the information sequence is presented in the form of bit blocks to be iteratively processed by primitive cryptographic transformations: functional operations of cyclic shift and addition modulo 2 (ShiftRow) using appropriate devices, substitution using substitution blocks (S-blocks); mixing (permutation) using blocks for mixing cubes (P-blocks); SlidCode functional operations using mixed Gray codes. Bit blocks of the information sequence are presented in the form of three-dimensional matrices (cubes) and as an S-block form a variable three-dimensional matrix of substitutions, which is constructed by obtaining a multiplicative inverse element x-1 over the extended Galois finite field GF (28) and by performing affine transformation y = M · x-1 ++ over the primitive Galois binary field GF (2). As the matrix of M-affine transformation, variable inverse symmetric matrices are used, which are selected according to the value of the cyclic key, and that the functional operations of substitution and mixing are not fixed, but depend on the state of the key. Iterative processing by primitive cryptographic transformations occurs in the following sequence: functional operations of cyclic shift and addition modulo 2 (ShiftRow), permutation. substitution, functional operations of sliding coding (SlidCode).

Description

The utility model belongs to the field of cryptographic information protection and can be used in encryption tools in information processing systems to expand their capabilities.

There is a known method of cryptographic transformation (1), which is based on the fact that the information sequence is presented in the form of 64-bit blocks, which are subject to iterative processing by primitive cryptographic transformations: permutation (repetition) - using permutation blocks (P-blocks); substitution (zIyB5iyshiop) - using blocks of substitutions (5-blocks); functional operations of cyclic shift and addition modulo 2 using appropriate devices. Iterative processing consists in multiple execution of the same groups of transformations, which provide the necessary conditions for stability of cryptographic transformation: scattering (using P-blocks) and mixing (using 5-blocks) of information data.

The disadvantages of this method are that a fixed matrix of substitutions acts as a 5-block for cryptographic transformation of information, which does not allow to flexibly change the parameters of cryptographic processing and dynamically control the process of shuffling information data, as well as the fact that fixed parameter values are used for the functional movement operation landslide

The closest analogue to the proposed useful model is the improved method of cryptographic transformation |2|, which is based on the fact that the information sequence is presented in the form of bit blocks, which are subject to iterative processing by primitive cryptographic transformations: shuffling (reptiiayop) using cube shuffling blocks (reptiiyazo blocks ); substitution (zyB5iyshiop) - using substitution blocks (5-blocks); functional operations of cyclic shift and addition according to module 2 (ZPSHAOm) - with the help of appropriate devices. At the same time, the bit blocks of the information sequence are presented in the form of three-dimensional matrices (cubes) and as a 5-block form a variable three-dimensional matrix of substitutions, which is constructed by obtaining the multiplicative inverse element x" over the extended finite Galois field CE(25) and by performing the affine transformation y-M :x"--B8 over the primitive Galois binary field SC(2), and as a matrix

M affine transformation uses variable inverse symmetric matrices, which are chosen

Zo according to the value of the cyclic key, and the functional operations of the cyclic shift are not fixed, but depend on the state of the key.

The disadvantages of the closest analogue are that for the cryptographic transformation of information as a 5-block, a fixed substitution matrix acts, which does not allow to flexibly change the parameters of cryptographic processing and dynamically control the process of substitution of information data, and that for cryptographic transformation of information, the substitution parameters are fixed, and that for the cryptographic transformation of information, the cyclic shift parameters are fixed.

The basis of a useful model is the task of creating a method of cryptographic transformation of information, which, due to the use of four three-dimensional cryptographic transformations (substitution, shuffling, cyclic shift and sliding coding), will make it possible to flexibly change the parameters of cryptographic processing and dynamically control the process of substitution and shuffling of information data in three-dimensional space , the functional operations of substitution and shuffling are not fixed, but depend on the state of the key, and that iterative processing by primitive cryptographic transformations occurs in the following sequence: functional operations of cyclic shift and addition modulo 2 (POM), shuffling (reptiiayop), substitution (5!ts051yyShiop ), functional operations of sliding coding (51id-Sode).

The task is solved by the fact that in the method of cryptographic transformation of information, which consists in the fact that the information sequence is presented in the form of bit blocks, which are subject to iterative processing by primitive cryptographic transformations: functional operations of cyclic shift and addition modulo 2 (ZPSHNOmM) using appropriate devices , substitution (zIyib5iyshiop) using blocks of substitutions (5-blocks); mixing (reptiiaiop) - with the help of cubes mixing blocks (P-blocks); functional operations of sliding coding (5iSode) - with the help of mixed Gray codes, according to a useful model, bit blocks of the information sequence are presented in the form of three-dimensional matrices (cubes), as a 5-block forms a variable three-dimensional substitution matrix, which is built by obtaining the multiplicative inverse element x" over the extended finite Galois field CE(28) and by performing the affine transformation y-M:x'-B over the primitive binary Galois field CE(2), and variable inverse symmetric matrices are used as the matrix M of the affine transformation, which are chosen according to the value of a cyclic key, and that the functional operations of substitution and shuffling are not fixed, but depend on the state of the key, and that iterative processing by primitive cryptographic transformations occurs in the following sequence: functional operations of cyclic shift and addition modulo 2 (ZPyAoOmM), shuffling (reptshaiyop), substitution (zirviyshiop), functional operations of sliding coding (51iaS ode).

The technical result that can be obtained when implementing a useful model consists in obtaining the ability to flexibly change the parameters of cryptographic processing of information data and dynamically control the process of substitution and mixing.

The method of cryptographic transformation of information is realized by the fact that the information sequence is presented in the form of 256 bit blocks, which are subject to iterative processing by primitive cryptographic transformations: functional operations of cyclic shift and addition modulo 2 (5PISHNOmMm) - using appropriate devices, substitution (vyrviyshiop) - using blocks of substitutions (5-blocks); shuffling (reptyshayop) using cube shuffling blocks (P-blocks); functional operations of sliding coding (BidSode) - with the help of mixed Gray codes. As a 5-block, there is a variable matrix of substitutions, which is constructed by obtaining the multiplicative inverse element x" over the extended finite Galois field CE(23) and by performing the affine transformation (1) over the primitive binary Galois field CE(2), and as a symmetric matrix M of the affine transformations use variable inverse symmetric matrices, which are chosen according to the value of the cyclic key, and that the functional operations of substitution and shuffling are not fixed, but depend on the state of the key, and that iterative processing by primitive cryptographic transformations occurs in the following sequence: functional operations of cyclic shift and addition by module 2 (5pPSHyNOm), shuffling (reptshaiyop), substitution (5!yrziyshiop), functional operations of sliding coding (51iaSoavye).

The cyclic key is generated from the encryption key using the key generation algorithm. The length of the cyclic key is equal to the length of the block. Cycle keys are generated from the encryption key using key expansion. The extended key is a linear array of 4-byte words. That is, at each iteration of the cryptographic transformation, a corresponding symmetric matrix M is used, which, with the help of a cyclic 4-byte key, can

Z is chosen from a large set of inverse matrices. This makes it possible to flexibly change the shuffling matrix in the process of cryptographic transformation and dynamically control the process of shuffling, substitution, cyclic shift and sliding coding of information data.

Depending on the state of the round key, the parameters of shuffling, substitution, cyclic shift and sliding coding are selected by adding modulo 2 all bytes of the key, setting 1 in the lower digit of the result of addition (to form an odd value) and getting rid of the higher digit of the result of addition (remaining 7 of 8 significant bits).

The final value determines the amount of shift in the current round.

Thus, due to the use of variable inverse symmetric matrices and a variable (dependent on the round key) substitution function, it is possible to apply dynamically changing substitution matrices and different values of sliding coding as a 5-block at each iteration of the cryptographic transformation of information, which makes it possible to flexibly change the parameters of cryptographic processing and dynamically control the process of substitution and mixing of information data in three-dimensional space.

Sources of information: 1. "RIR5 ROV 46-3" RGEOEVAI IMEOVMATIOM RAVOSEBBIMIa ZTAMOANVOV ROVI ISATIOM. RATA EMSAMURTIOM ZTAMOANVO (OE5). - 1999, OKIobeg 25. - R. 26. pEruLlymly. emeguzres.sot/MIZT/MIZT-RIRB/dompiosaya. рыр"зрес-БИР5 ROIV 46-3.030171. rai. 2. Patent of Ukraine for a utility model, Mo 99696, IPC p209С 1/00 (2015.01). Method of cryptographic transformation of information / Bilenky A.Ya., Navrotskyi D.O.; applicant and patent holder National Aviation University - MO 201404060; application 04/16/2014; published 06/25/2015, Bulletin Mo 12. - 5 p.

Claims (1)

USEFUL MODEL FORMULA The method of cryptographic transformation of information, which consists in the fact that the information sequence is presented in the form of bit blocks, which are subject to iterative processing by primitive cryptographic transformations: functional operations of cyclic shift and addition modulo 2 (ZNPSHNOm) with the help of appropriate devices, substitution (5!rviyshiop) using substitution blocks (5-blocks); mixing (repeating) using blocks 60 mixing cubes (P-blocks); functional operations of sliding coding (51iySode) using mixed Gray codes, which is distinguished by the fact that the bit blocks of the information sequence are presented in the form of three-dimensional matrices (cubes) and as a 5-block form a variable three-dimensional matrix of substitutions, which is constructed by obtaining the multiplicative inverse element x" over by the extended finite Galois field CE(25) and by performing the affine transformation y-M:x"--rD over the primitive binary Galois field CE(2), and as the matrix M- affine transformation uses variable inverse symmetric matrices, which are chosen according to the value of the cyclic key, and that the functional operations of substitution and shuffling are not fixed, but depend on the state of the key, and that iterative processing by primitive cryptographic transformations occurs in the following sequence: functional operations of cyclic shift and addition by module 2 (5PyNVoOhm), mixing (reptiiaiiyop). substitution (virviyshiop), functional operations of sliding coding (51IiaSoavye).