Author

# Mammadolimov Abdulrashid

Bio: Mammadolimov Abdulrashid is an academic researcher. The author has contributed to research in topics: Centrosymmetric matrix & Single-entry matrix. The author has an hindex of 1, co-authored 1 publications receiving 4 citations.

##### Papers

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17 Jun 2011

TL;DR: In this paper, the authors presented a method of linear transformation in substitution-permutation network symmetric-key block cipher (SPSC) for key-dependent MDS matrices.

Abstract: One embodiment of the present invention is a method of linear transformation in Substitution-Permutation Network symmetric-key block cipher producing n x n key-dependent MDS matrices from given n x n MDS matrix by scalar multiplication and permutations of elements of given matrix where multiplicative scalar and permutations are derived from binary inputs of length l . The method comprising deriving multiplicative scalar from binary input; multiplying given matrix with multiplicative scalar, producing first intermediate matrix; deriving first permutation of n objects from binary input; permuting rows of first intermediate matrix according to first permutation, producing second intermediate matrix; deriving second permutation of n objects from binary input; and permuting columns of second intermediate matrix according to second permutation to produce final MDS matrix. Another embodiment of the present invention is a method of linear transformation in Substitution-Permutation Network symmetric-key block cipher producing n x n key-dependent MDS matrices from given n x n MDS matrix by scalar multiplication and permutations of elements of given matrix where multiplicative scalar and permutations are derived from binary inputs of length l . The method comprising deriving multiplicative scalar from the key (202); multiplying given matrix with multiplicative scalar to produce first intermediate matrix (204); deriving first permutation of n objects from the key (206); permuting rows of first intermediate matrix according to first permutation to produce second intermediate matrix (208); deriving second permutation of n objects from the key (304); and permuting columns of second intermediate matrix according to second permutation (212) to produce final MDS matrix (214).

4 citations

##### Cited by

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Artemis

^{1}TL;DR: In this paper, a ring cam and a plurality of working chambers are mounted to rotate relative to each other, cycles of working chamber volume being coupled to rotation of the ring cam relative to the working chambers.

Abstract: A fluid-working machine for a renewable energy generation device, the fluid-working machine comprising a ring cam and a plurality of working chambers, the ring cam having an annular working surface extending around an axis of rotation of the ring cam, the annular working surface defining a plurality of waves, each working chamber having a piston, each piston in operative engagement with the ring cam working surface, the ring cam and working chambers being mounted to rotate relative to each other, cycles of working chamber volume being thereby coupled to rotation of the ring cam relative to the working chambers, characterised in that the individual waves of the ring cam working surface have an asymmetric profile.

14 citations

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Artemis

^{1}TL;DR: In this paper, a ring cam is formed from a plurality of segments, including a leading cooperating formation (46) and a trailing cooperating formation(40), with a piston facing surface which forms part of the working surface at a leading end, and which is recessed from the working surfaces at a trailing end.

Abstract: A ring cam (1 ) for a fluid-working machine is formed from a plurality of segments. (5, 7) The segments have piston facing surfaces (15, 16)together defining a working surface of the fluid-working machine. The segments comprise a leading cooperating formation (46) which has a piston facing surface which forms part of the working surface, at a trailing end, and which is recessed from the working surface at a leading end, and a trailing cooperating formation (40) which has a piston facing surface which forms part of the working surface at a leading end, and which is recessed from the working surface at a trailing end. The cooperating formations interlock and rollers (9) are thereby handed over smoothly from one segment to the next irrespective of slight variations in alignment due to manufacturing tolerance or wear. The segments having piston facing surfaces which are in compressive stress such as to partially or fully compensate for tensile stress arising from the action of rollers in use. The segments form a wavelike cam surface and attachment means (3) are provided, through the working surface, on whichever of the leading or trailing surfaces thereof is subject to lowest forces from pistons in use.

12 citations

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01 Oct 2015

TL;DR: Some new results on direct exponent transformation are presented to show the k* number (cycle) that direct p exponent of the MDS matrix fork times results in the original M DS matrix, which has important applications in block ciphers.

Abstract: MDS code has been studied for a long time in the theory of error-correcting code and has been applied widely in cryptography. Some authors studied and proposed some methods for constructing MDS matrices which do not based on MDS code. Some MDS matrix transformations have been studied and direct exponent is such a transformation. In this paper we present some new results on direct exponent transformation to show the k* number (cycle) that direct p exponent of the MDS matrix fork times results in the original MDS matrix. In addition, the results are shown to have important applications in block ciphers.

3 citations

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01 Jun 2017

TL;DR: The process of encryption and decryption by dynamic MDS matrices is proven to be calculated more quickly by salvaging the original M DS matrices.

Abstract: MDS (Maximum Distance Separable) matrices have an important role in the design of block ciphers and hash functions. The methods for transforming an MDS matrix into other ones to create dynamic MDS matrix for use have been proposed by many authors in the literature. In this paper, dynamic MDS matrices generated from direct exponent and scalar multiplication transformations are studied in the term of calculating effectively the outputs of the dynamic MDS matrices based on original MDS matrices when the inputs are known, as well as the calculating effectively the inputs of the dynamic MDS matrices based on original MDS matrices when the outputs are known. The process of encryption and decryption by dynamic MDS matrices is proven to be calculated more quickly by salvaging the original MDS matrices. In addition, a way for calculating quickly the direct exponent of MDS matrices based on a lookup table is presented.

2 citations