1,216 research outputs found

    Trusted-HB: a low-cost version of HB+ secure against Man-in-The-Middle attacks

    Full text link
    Since the introduction at Crypto'05 by Juels and Weis of the protocol HB+, a lightweight protocol secure against active attacks but only in a detection based-model, many works have tried to enhance its security. We propose here a new approach to achieve resistance against Man-in-The-Middle attacks. Our requirements - in terms of extra communications and hardware - are surprisingly low.Comment: submitted to IEEE Transactions on Information Theor

    Depletion interactions of non-spherical colloidal particles in polymer solutions

    Full text link
    We consider anisotropic colloidal particles immersed in a solution of long, flexible, and nonadsorbing polymers. For the dumbbell shapes of recently synthesized particles consisting of two intersecting spheres and for lens-shaped particles with spherical surfaces we calculate the isotropic and anisotropic interaction parameters that determine the immersion free energy and the orientation-dependent depletion interaction between particles that are induced by the polymers. Exact results are obtained for random-walk like (ideal) polymer chains

    Dresselhaus spin-orbit coupling in [111]-oriented semiconductor nanowires

    Full text link
    The contribution of bulk inversion asymmetry to the total spin-orbit coupling is commonly neglected for group III-V nanowires grown in the generic [111] direction. We have solved the complete Hamiltonian of the circular nanowire accounting for bulk inversion asymmetry via exact numerical diagonalization. Three different symmetry classes of angular momentum states exist, which reflects the threefold rotation symmetry of the crystal lattice about the [111] axis. A particular group of angular momentum states contains degenerate modes which are strongly coupled via the Dresselhaus Hamiltonian, which results in a significant energy splitting with increasing momentum. Hence, under certain conditions Dresselhaus spin-orbit coupling is relevant for [111] InAs and [111] InSb nanowires. We demonstrate momentum-dependent energy splittings and the impact of Dresselhaus spin-orbit coupling on the dispersion relation. In view of possible spintronics applications relying on bulk inversion asymmetry we calculate the spin expectation values and the spin texture as a function of the Fermi energy. Finally, we investigate the effect of an axial magnetic field on the energy spectrum and on the corresponding spin polarization.Comment: 11 Pages, 7 figure

    Security and Efficiency Analysis of the Hamming Distance Computation Protocol Based on Oblivious Transfer

    Get PDF
    open access articleBringer et al. proposed two cryptographic protocols for the computation of Hamming distance. Their first scheme uses Oblivious Transfer and provides security in the semi-honest model. The other scheme uses Committed Oblivious Transfer and is claimed to provide full security in the malicious case. The proposed protocols have direct implications to biometric authentication schemes between a prover and a verifier where the verifier has biometric data of the users in plain form. In this paper, we show that their protocol is not actually fully secure against malicious adversaries. More precisely, our attack breaks the soundness property of their protocol where a malicious user can compute a Hamming distance which is different from the actual value. For biometric authentication systems, this attack allows a malicious adversary to pass the authentication without knowledge of the honest user's input with at most O(n)O(n) complexity instead of O(2n)O(2^n), where nn is the input length. We propose an enhanced version of their protocol where this attack is eliminated. The security of our modified protocol is proven using the simulation-based paradigm. Furthermore, as for efficiency concerns, the modified protocol utilizes Verifiable Oblivious Transfer which does not require the commitments to outputs which improves its efficiency significantly

    Flexible Automatic Scheduling For Autonomous Telescopes: The MAJORDOME

    Full text link
    We have developped a new method for the scheduling of astronomical automatic telescopes, in the framework of the autonomous TAROT instrument. The MAJORDOME software can handle a variety of observations, constrained, periodic, etc., and produces a timeline for the night, which may be modified at any time to take into account the specific conditions of the night. The MAJORDOME can also handle target of opportunity observations without delay.Comment: 16 pages, 6 figures, to appear in Experimental Astronom

    Online media attribution of pipeline infrastructure failure, sourcing and the public health model: a content analysis of news stories on water and wastewater pipeline failures

    Get PDF
    Title from PDF of title page (University of Missouri--Columbia, viewed on May 26, 2011).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Thesis advisor: Dr. Shelly Rodgers.Includes bibliographical references.M.A. University of Missouri--Columbia 2011.The following study is a content analysis on how online media covers pipeline failure in North America. It uses the Public Health Model of Reporting, Sourcing and Attribution Theory to answer questions related to the cause and consequences of pipeline failure. The content analysis looked at 112 articles from 2010 highlighting events and issues related to pipeline and infrastructure failure such as sewer collapses, water main breaks and sinkholes. The articles were coded for frequency of the various failures, consequences and causes. The story type and sources of all articles were also coded to determine if there were any relationships between the variables. Additional information was gathered relating to other criteria specific to online articles, such as the availability of photos and video and social media feedback

    Optimal Iris Fuzzy Sketches

    Full text link
    Fuzzy sketches, introduced as a link between biometry and cryptography, are a way of handling biometric data matching as an error correction issue. We focus here on iris biometrics and look for the best error-correcting code in that respect. We show that two-dimensional iterative min-sum decoding leads to results near the theoretical limits. In particular, we experiment our techniques on the Iris Challenge Evaluation (ICE) database and validate our findings.Comment: 9 pages. Submitted to the IEEE Conference on Biometrics: Theory, Applications and Systems, 2007 Washington D
    • …
    corecore