UA119574U - METHOD OF CRYPTOGRAPHICAL TRANSFER 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 that are subject to iterative processing by primitive cryptographic transformations: permutation - using blocks of mixing cubes (P-blocks); substitution - by means of substitution blocks (S-blocks); functional cyclic shift and modulation operations 2 (ShiftRow) - using appropriate devices, functional sliding coding operations (SlidCode) - using mixed Gray codes. The bit blocks of the information sequence are presented in the form of three-dimensional matrices (cubes) and as the S-block form a variable three-dimensional matrix of substitutions, which is constructed by obtaining a multiplicatively inverse x-1 element over the extended Galois finite field GF (28) and by performing the affine transformation y = M · x-1 + (over the primitive Galois binary field GF (2). As the affine transformation matrix M, we use variable inverted symmetric matrices that are selected according to the value of the cycle key, and that the functional operations of mixing, substitutions and sliding coding is not fixed, but depends on the state of the key.

Description

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

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 (reptiiaop) - using permutation blocks (P-blocks); substitution ( zIyB5iyshiop) - using substitution blocks (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 the stability of cryptographic transformation: scattering (using P-blocks) and shuffling (using 5-blocks) information data.

The disadvantages of this method are that for the cryptographic transformation of information as a 5-block, a fixed matrix of substitutions is used, 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 for the functional shuffling operation, fixed parameter values are used landslide

The closest to the proposed technical solution, chosen as a prototype, is an 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 (regtshiiaiiop) - using blocks mixing of cubes (ReptiyaZ30 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, and it is constructed by obtaining the multiplicative inverse element x" over the extended finite field of Hal and CE(28) and by performing an affine transformation in - Mkh"--r over the primitive binary Galois field CE(2), while 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 prototype method are that for cryptographic transformation of information as

C-block is a fixed substitution matrix, 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 cryptographic transformation of information, the cyclic shift parameters are fixed.

The useful model is based on the task of creating a method of cryptographic transformation of information, which, due to the use of four three-dimensional cryptographic transformations (shuffling, substitution, cyclic shift and sliding coding), will make it possible to flexibly change the parameters of cryptographic processing and dynamically control the process of substitution of information data in three-dimensional space, and that the parameters of substitution, substitution and sliding coding change dynamically depending on the state of the key.

The task is solved due to the fact that 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: shuffling (reptiiyaop) - with the help of blocks of shuffling cubes (P-blocks) ; substitution (5!irviyshiop) - using substitution blocks (5-blocks); functional operations of cyclic shift and addition modulo 2 (ZNSHNOmM) - with the help of appropriate devices, functional operations of sliding coding (5iiYaiSode) - with the help of mixed Gray codes, in which, according to a useful model, 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 substitution matrix, which is constructed by obtaining the multiplicative inverse element x" over the extended finite Galois field CE(28) and by performing the affine transformation y-M'.x"-8 over the primitive binary Galois field CE (2), while variable inverse symmetric matrices are used as the matrix M of the affine transformation, which are chosen according to the value of the cyclic key, and that the functional operations of shuffling, substitution, and sliding coding are not fixed, but depend on the state of the key.

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 and data and dynamically control the process of shuffling, substitution and sliding coding.

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: shuffling (regtshiiyaaiyop) - with the help of cubes shuffling blocks (P-blocks); substitution (5!Ir5iyshiop) - using blocks of substitutions (5-blocks); functional operations of cyclic shift and addition according to module 2 (ZPSHAoOMM) - with the help of appropriate devices; functional operations of sliding coding (BidSoade) - using 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 SB(23) and by performing the affine transformation (1) over the primitive binary Galois field CE(2), while as a symmetric matrix M affine transformation uses variable inverse symmetric matrices that are chosen according to the value of the cyclic key, and that the functional operations of shuffling, substitution, and sliding coding are not fixed, but depend on the state of the key.

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 can be selected from a large set of inverse matrices with the help of a cyclic 4-byte key. This makes it possible to flexibly change the shuffling matrix in the process of cryptographic transformation and dynamically control the process of shuffling, substitution and sliding coding of information data.

Depending on the state of the round key, the parameter of shuffling, substitution, cyclic shift and sliding coding is 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 (remains 7 with 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 (depending on the round key) substitution function, it is possible to apply dynamically changing 5-blocks at each iteration of the cryptographic transformation of information

From the matrix of substitutions and different amounts of sliding coding, which makes it possible to flexibly change the parameters of cryptographic processing and dynamically control the process of shuffling, substitution and sliding coding of information data in three-dimensional space.

Sources of information: 1. "RIR5 ROV 46-3" GEOEVAI IMEOVMATIOM RAVOSEBBIMIa ZTAMOANVOV ROVI ISATIOM. RATA EMSAMRTIOM ZTAMOANVO (OE5) 1999 OKiobeg 25, radez 26. pEruLlymly. emeguizres.sot/MIZT/MIZT-RIRB/dompioai. ryr"zres-RIRZ ROV 46-3.030171. rai 2. Method of cryptographic transformation of information: patent 94189: IPC 2014-01 /

Biletskyi A.Ya., Navrotskyi D.O.; patent holder National Aviation University. -

Mo201312117; statement 16.10.2013; published 10.11.2014, Bull. Mo21.-5b.

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: shuffling (reptiiyaop) - with the help of cubes shuffling blocks (P-blocks); substitution (zibviyshiop) - using substitution blocks (5-blocks); functional operations of cyclic shift and addition modulo 2 (ZPSHNVOmU) - using appropriate devices, functional operations of sliding coding (5iiySode) - 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 that as a 5-block form a variable three-dimensional matrix of substitutions, which is built by obtaining the multiplicatively inverse element x! over the extended finite Galois field CE(25) and by performing the affine transformation y-M:x"--D over the primitive binary Galois field CE(2), while variable inverse symmetric matrices are used as the matrix M of the affine transformation, which are chosen according to the value of the cyclic key, and that the functional operations of scrambling, substitution, and sliding coding are not fixed, but depend on the state of the key.