Privacy-Aware Processing of Biometric Templates by Means of Secure Two-Party Computation

The use of biometric data for person identification and access control is gaining more and more popularity. Handling biometric data, however, requires particular care, since biometric data is indissolubly tied to the identity of the owner hence raising important security and privacy issues. This chapter focuses on the latter, presenting an innovative approach that, by relying on tools borrowed from Secure Two Party Computation (STPC) theory, permits to process the biometric data in encrypted form, thus eliminating any risk that private biometric information is leaked during an identification process. The basic concepts behind STPC are reviewed together with the basic cryptographic primitives needed to achieve privacy-aware processing of biometric data in a STPC context. The two main approaches proposed so far, namely homomorphic encryption and garbled circuits, are discussed and the way such techniques can be used to develop a full biometric matching protocol described. Some general guidelines to be used in the design of a privacy-aware biometric system are given, so as to allow the reader to choose the most appropriate tools depending on the application at hand

Correction: Anisotropy of the vorticity tensor as a magnetic indicator of aromaticity.

Correction for 'Anisotropy of the vorticity tensor as a magnetic indicator of aromaticity' by S. Pelloni et al., Phys. Chem. Chem. Phys., 2020, 22, 1299–1305, DOI: 10.1039/C9CP05563K

Current density maps, magnetizability, and nuclear magnetic shielding tensors of bis-heteropentalenes. II. Furo-furan Isomers

Magnetic susceptibility and nuclear magnetic shielding at the nuclei of bis-heteropentalenes formed by two furan units ([2,3-b], [3,2-b], [3,4-b], and [3,4-c] isomers) have been computed by several approximated techniques and a large Gaussian basis set to achieve near Hartree–Fock estimates. Ab initio models of the ring currents induced by a magnetic field normal to the molecular plane were obtained for the three isomeric systems of higher symmetry, showing that the π electrons give rise to intense diamagnetic circulation. The π currents are responsible for enhanced magnetic anisotropy and strong out-of-plane proton deshielding. The theoretical findings are used to build up a “diatropicity matrix” for two fused five-membered heterocyclic [email protected] ; [email protected]

Dynamical-charge neutrality at a crystal surface

For both molecules and periodic solids, the ionic dynamical charge tensors which govern the infrared activity are known to obey a dynamical neutrality condition. This condition enforces their sum to vanish (over the whole finite system, or over the crystal cell, respectively). We extend this sum rule to the non trivial case of the surface of a semiinfinite solid and show that, in the case of a polar surface of an insulator, the surface ions cannot have the same dynamical charges as in the bulk. The sum rule is demonstrated through calculations for the Si-terminated SiC(001) surface.Comment: 4 pages, latex file, 1 postscript figure automatically include

Theoretical estimates of the anapole magnetizabilities of C4H4X2 cyclic molecules for X=O, S, Se, and Te

Calculations have been carried out for C4H4X2 cyclic molecules, with X=O, S, Se, and Te, characterized by the presence of magnetic-field induced toroidal electron currents and associated orbital anapole moments. The orbital anapole induced by a static nonuniform magnetic field B, with uniform curl C =∇× B, is rationalized via a second-rank anapole magnetizability tensor aαβ , defined as minus the second derivative of the second-order interaction energy with respect to the components Cα and Bβ. The average anapole magnetizability a equals −χ, the pseudoscalar obtained by spatial averaging of the dipole-quadrupole magnetizability χα,βγ . It has different sign for D and L enantiomeric systems and can therefore be used for chiral discrimination. Therefore, in an isotropic chiral medium, a homogeneous magnetic field induces an electronic anapole Aα, having the same magnitude, but opposite sign, for two enantiomorphs.Fil: Pagola, Gabriel Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Ferraro, Marta Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Provasi, Patricio Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Modelado e Innovación Tecnológica. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Modelado e Innovación Tecnologica; ArgentinaFil: Pelloni, Stefano. Universidad de Modena y Reggio Emilia. Departamento de Química; ItaliaFil: Lazzeretti, Paolo. Universidad de Modena y Reggio Emilia. Departamento de Química; Italia; Itali

When are Antiaromatic Molecules Paramagnetic?

Magnetizabilities and magnetically induced current densities have been calculated and analyzed for a series of antiaromatic cyclo[4k]carbons (k = 2-11), iso[n]phlorins (n = 4-8), expanded porphyrinoids, and meso-meso, beta-beta,beta-beta triple-linked porphyrin and isophlorin arrays. The cyclo[4k]carbons with k = 2-6 are predicted to be closed-shell paramagnetic molecules due to the very strong paratropic ring current combined with its large radius. Larger cyclo[4k]carbons with k = 6-11 are diamagnetic because they sustain a paratropic ring current whose strength is weaker than -20 nA T-1, which seems to be the lower threshold value for closed-shell paramagnetism. This holds not only for cyclo[4k]carbons but also for other organic molecules like expanded porphyrinoids and oligomers of porphyrinoids. The present study shows that meso-meso, beta-beta, beta-beta triple-linked linear porphyrin and isophlorin arrays have a domainlike distribution of alternating diatropic and paratropic ring currents. The strength of their local paratropic ring currents is weaker than -20 nA T-1 in each domain. Therefore, linear porphyrin and isophlorin arrays become more diamagnetic with increasing length of the ribbon. For the same reason, square-shaped meso-meso, beta-beta, beta-beta triple-linked free-base porphyrin and isophlorin tetramers as well as the Zn(II) complex of the porphyrin tetramer are diamagnetic. We show that closed-shell molecules with large positive magnetizabilities can be designed by following the principle that a strong paratropic current ring combined with a large ring-current radius leads to closed-shell paramagnetism.Peer reviewe

The Electronic Origin of Geometrical Deformations in Cyclohexadienyl and Cyclobutenyl Transition Metal Complexes

(40) (a) Davies4' has stated the opinion that ". . . the comparatlve success of London's method for aromatic hydrocarbons may be attributed to the dependence of the theoretical anisotropy on the square of the area of the rings in a molecule'' and that ". . . any method that takes this into account is likely to give reasonable results for the ratio . . ." of a given calculated anisotropy to that calculated, by the same method, for benzene. We might also add that, at least for paramagnetic systems of the type considered here, another important requirement for obtaining 'reasonable' ratios is the use of a a-electron wave function which is Iteratively self-consistent with respect to atomic charges and bond orders. (see subsection 4 of this section). The Electronic Origin of Geometrical Deformations in Cyclohexadienyl and Cyclobutenyl Transition Metal Complexes Roald Hoffmann* and Peter Hofmann Contribution from the Department of Chemistry. Cornell University, Ithaca, New York 14850. Received May 19,1975 Abstract: A case is presented for an electronic factor in the out-of-plane bending of the saturated carbon in cyclohexadienyl-M(CO)3 complexes, M = Fe+, Mn, Cr-. In the cyclohexadienyl ligand hyperconjugation extends the nonbonding MO wave function to the methylene hydrogens. The phase of the CH2 hydrogen contributions to that MO is such that when the C6H7 ligand is bound to the M(C0)3 group there arises a secondary M-CHz interaction which is destabilizing. In cyclobutenyl and cyclooctatrienyl complexes this interaction is lacking and thus these should be less bent than cyclohexadienyl complexes. A similar analysis rationalizes the bending away from the metal in cyclopentadiene-Fe(C0)3 complexes, its lessening in cyclopentadienone complexes, and the bending toward the metal in fulvene or cyclopentadienyl-carbonium ion complexes. The charge distribution and substituent effects in C6H,M(CO)3 complexes are examined, as well as a case of hypothetical isomerism in benzyl-M(C0)3. There exists a substantial chemistry of transition metal complexes of cyclohexadienyl and cyclobutenyl ligands, exemplified by structure 1. Examples exist for M = Fe+, Mn, Cr-, and their lower transition series analogues. The assign- 3 . 4 1 ment of a formal charge to the metal is, of course, arbitrary. Nevertheless it focuses on the basic electronic similarity of these complexes, an aspect that might be obscured by an argument over the cationic or anionic nature of the coordinated cyclohexadienyl ligand. In all known structures of type 1 the six-membered organic ring is highly nonplanar, and distorted in the same way-atoms 1 through 5 remain in an approximate plane, but the saturated carbon 6 moves out of that plane and away from the metal. It should be noted that the free organic ligand is either planar or only moderately distorted. In the crystal structure of the tetrachloroaluminate salt of the heptamethylbenzenonium cation, 2, the six-membered ring is essentially planar.' However, in three recent structures of stabilized u complexes, 3,1° dihedral angles up to 17' have been found.'' Stabilized anionic u complexes, that is Meisenheimer complexes, have been known for some time.l* Several crystal structures of such highly substituted cyclohexadienyl anions are a~a i l a b l e , '~ and in all the six-membered ring is approximately planar. The problem of potential nonplanarity of cyclohexadienyl radicals has been discussed re~e n t 1 y . I~ At any rate it is clear that upon formation of a transition metal complex there is a significant enhancement of th

Environment influences on the aromatic character of nucleobases and amino acids

Geometric (HOMA) and magnetic (NICS) indices of aromaticity were estimated for aromatic rings of amino acids and nucleobases. Cartesian coordinates were taken directly either from PDB files deposited in public databases at the finest resolution available (≤1.5 Å), or from structures resulting from full gradient geometry optimization in a hybrid QM/MM approach. Significant environmental effects imposing alterations of HOMA values were noted for all aromatic rings analysed. Furthermore, even extra fine resolution (≤1.0 Å) is not sufficient for direct estimation of HOMA values based on Cartesian coordinates provided by PDB files. The values of mean bond errors seem to be much higher than the 0.05 Å often reported for PDB files. The use of quantum chemistry geometry optimization is strongly advised; even a simple QM/MM model comprising only the aromatic substructure within the QM region and the rest of biomolecule treated classically within the MM framework proved to be a promising means of describing aromaticity inside native environments. According to the results presented, three consequences of the interaction with the environment can be observed that induce changes in structural and magnetic indices of aromaticity. First, broad ranges of HOMA or NICS values are usually obtained for different conformations of nearest neighborhood. Next, these values and their means can differ significantly from those characterising isolated monomers. The most significant increase in aromaticities is expected for the six-membered rings of guanine, thymine and cytosine. The same trend was also noticed for all amino acids inside proteins but this effect was much smaller, reaching the highest value for the five-membered ring of tryptophan. Explicit water solutions impose similar changes on HOMA and NICS distributions. Thus, environment effects of protein, DNA and even explicit water molecules are non-negligible sources of aromaticity changes appearing in the rings of nucleobases and aromatic amino acids residues

Prato: The Social Construction of an Industrial City Facing Processes of Cultural Hybridization

This chapter deals with a widely studied case, that is, Prato, a middle-sized city with rooted industrial traditions, in the Centre of Italy. Prato is a textile industrial district embedded in the so-called Third Italy—an area characterized by the presence of small firms spread throughout the territory, linked together in supply and subcontracting relationships—which, in the last twenty years, has undergone a profound transformation as a consequence of the crisis of textile and immigration, leading to the formation of a large Chinese community. The related changes brought with them problems of social cohesion and sustainable development. The authors address these issues by analyzing both academic and public discourses on Prato. Their basic idea is that common stereotypes act as drivers of a public discourse that prevents the city to re-negotiate its identity. The analysis concludes that different forms of hybridization—particularly cultural hybridization—are occurring, which would need further investigations