30 research outputs found

    Weights on affine subspaces and some other cryptographic characteristics of Boolean functions of 5 variables

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    Recently one new key recovery method for a filter generator was proposed. It is based on so-called planar approximations of such a generator. This paper contains the numerical part of the research of the Boolean functions properties which allow to protect the generator against this method. The main theoretical part of this research is presented at the CTCrypt 2019 conference

    Security bound for CTR-ACPKM internally re-keyed encryption mode

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    In 2018 the CTR-ACPKM internally re-keyed block cipher mode was adopted in Russian Standardization System and must pass through the last formal standardization stages in IETF. The main distinctive feature of this mode is that during each message processing, the key, used for data blocks transformation, is periodically changed. In the current paper we obtained the security bound for this mode in the standard IND-CPNA security model

    On the properties of the CTR encryption mode of the Magma and Kuznyechik block ciphers with re-keying method based on CryptoPro Key Meshing

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    This paper presents a security bound in the standard security model for the Magma cipher CTR encryption mode and the «CryptoPro Key Meshing» (CPKM) re-keying method that was previously used with the GOST 28147-89 cipher. We enumerate the main requirements that should be followed during the development of re-keying methods, then we propose a modified method and justify its advantages over CPKM. We also obtain certain results about the operational features of the Kuznyechik cipher CTR encryption mode with several re-keying methods

    Nanoscale building blocks in a novel lithium arsenotungsten bronze: Synthesis and characterization

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    We report on a novel compound Li3AsW7O25 obtained by solid-state reaction and characterized by diffraction and spectroscopic methods. The bronze-type compound crystallizes in the orthorhombic space group Pbca with a=724.38(3) pm, b=1008.15(4) pm, c=4906.16(17) pm and Z=8. The structure is built up by chains of WO6 octahedra interconnected by AsO4 tetrahedra and WO6 octahedra forming a polyhedral arrangement as seen in intergrowth tungsten bronzes. The X-ray single crystal structure refinement allows solving the complex arsenotungstate framework. The powder neutron diffraction data analysis locates the lithium atoms. Thermal analysis showed that Li3AsW7O25 is stable up to its melting at 1135(3) K followed by a decomposition at 1182(5) K. The Kubelka–Munk treatment of the UV–vis spectrum revealed a wide band gap in the range of 2.84–3.40 eV depending on the presumed electron transition type

    Chirality and Polarity in the f-Block Borates M4_{4} [B16_{16} O 26_{26} (OH) 4_{4} (H 2_{2} O) 3_{3} Cl 4_{4} ] (M=Sm, Eu, Gd, Pu, Am, Cm, and Cf)

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    The reactions of trivalent lanthanides and actinides with molten boric acid in high chloride concentrations result in the formation of M4[B16O26(OH)4(H2O)3Cl4] (M=Sm, Eu, Gd, Pu, Am, Cm, Cf). This cubic structure type is remarkably complex and displays both chirality and polarity. The polymeric borate network forms helical features that are linked via two different types of nine-coordinate f-element environments. The f–f transitions are unusually intense and result in dark coloration of these compounds with actinides

    Unexpected Structural Complexity in Cesium Thorium Molybdates

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    Three cesium thorium molybdates [Cs2Th(MoO4)3, Cs2Th3(MoO4)7, and Cs4Th(MoO4)4] were synthesized via the high-temperature solid-state method. Cs2Th(MoO4)3 crystallizes in orthorhombic space group Pnnm, containing [Th(MoO4)3]2– chains extending along the [100] direction. Cs2Th3(MoO4)7 is based on an open framework with channels occupied by Cs+ ions and running parallel through the [100] direction. It is the first case in which thorium atoms coordinate simultaneously in three distinct environments, namely, 7-coordinated pentagonal bipyramid, 8-coordinated square antiprism, and 9-coordinated tricapped trigonal prism. Cs4Th(MoO4)4 is monoclinic, built from [Th(MoO4)4]4– sheets formed by vertex sharing of MoO4 tetrahedra and ThO8 antiprisms. The Raman and infrared spectra were recorded, and the vibrations related to internal and external Mo–O bonds in the MoO42– coordination geometry were discusse
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