160 research outputs found

    Practical Improvements of Profiled Side-Channel Attacks on a Hardware Crypto-Accelerator

    Get PDF
    Abstract. This article investigates the relevance of the theoretical frame-work on profiled side-channel attacks presented by F.-X. Standaert et al. at Eurocrypt 2009. The analyses consist in a case-study based on side-channel measurements acquired experimentally from a hardwired crypto-graphic accelerator. Therefore, with respect to previous formal analyses carried out on software measurements or on simulated data, the inves-tigations we describe are more complex, due to the underlying chip’s architecture and to the large amount of algorithmic noise. In this dif-ficult context, we show however that with an engineer’s mindset, two techniques can greatly improve both the off-line profiling and the on-line attack. First, we explore the appropriateness of different choices for the sensitive variables. We show that a skilled attacker aware of the regis-ter transfers occurring during the cryptographic operations can select the most adequate distinguisher, thus increasing its success rate. Sec-ond, we introduce a method based on the thresholding of leakage data to accelerate the profiling or the matching stages. Indeed, leveraging on an engineer’s common sense, it is possible to visually foresee the shape of some eigenvectors thereby anticipating their estimation towards their asymptotic value by authoritatively zeroing weak components containing mainly non-informational noise. This method empowers an attacker, in that it saves traces when converging towards correct values of the secret. Concretely, we demonstrate a 5 times speed-up in the on-line phase of the attack.

    Chiral effective field theories of the strong interactions

    Full text link
    Effective field theories of the strong interactions based on the approximate chiral symmetry of QCD provide a model-independent approach to low-energy hadron physics. We give a brief introduction to mesonic and baryonic chiral perturbation theory and discuss a number of applications. We also consider the effective field theory including vector and axial-vector mesons.Comment: 22 pages, 9 figures, proceedings of "Many-Body Structure of Strongly Interacting Systems", Mainz, Germany, Feb. 23-25 201

    Low-power silicon-organic hybrid (SOH) modulators for advanced modulation formats

    Get PDF
    We demonstrate silicon-organic hybrid (SOH) electro-optic modulators that enable quadrature phase-shift keying (QPSK) and 16-state quadrature amplitude modulation (16QAM) with high signal quality and record-low energy consumption. SOH integration combines highly efficient electro-optic organic materials with conventional silicon-on-insulator (SOI) slot waveguides, and allows to overcome the intrinsic limitations of silicon as an optical integration platform. We demonstrate QPSK and 16QAM signaling at symbol rates of 28 GBd with peak-to-peak drive voltages of 0.6 Vpp. For the 16QAM experiment at 112 Gbit/s, we measure a bit error ratio of 5.1 Ă— 10-5 and a record-low energy consumption of only 19 fJ/bit

    Femtojoule electro-optic modulation using a silicon-organic hybrid device

    Get PDF
    Energy-efficient electro-optic modulators are at the heart of short-reach optical interconnects, and silicon photonics is considered the leading technology for realizing such devices. However, the performance of all-silicon devices is limited by intrinsic material properties. In particular, the absence of linear electro-optic effects in silicon renders the integration of energy-efficient photonic-electronic interfaces challenging. Silicon-organic hybrid (SOH) integration can overcome these limitations by combining nanophotonic silicon waveguides with organic cladding materials, thereby offering the prospect of designing optical properties by molecular engineering. In this paper, we demonstrate an SOH Mach-Zehnder modulator with unprecedented efficiency: the 1-mm-long device consumes only 0.7 fJ bit-1 to generate a 12.5 Gbit s-1 data stream with a bit-error ratio below the threshold for hard-decision forward-error correction. This power consumption represents the lowest value demonstrated for a non-resonant Mach-Zehnder modulator in any material system. It is enabled by a novel class of organic electro-optic materials that are designed for high chromophore density and enhanced molecular orientation. The device features an electro-optic coefficient of r33~180 pm V-1 and can be operated at data rates of up to 40 Gbit s-1

    Nucleon mass and sigma term from lattice QCD with two light fermion flavors

    Get PDF
    We analyze Nf=2 nucleon mass data with respect to their dependence on the pion mass down to mpi = 157 MeV and compare it with predictions from covariant baryon chiral perturbation theory (BChPT). A novel feature of our approach is that we fit the nucleon mass data simultaneously with the directly obtained pion-nucleon sigma-term. Our lattice data below mpi = 435 MeV is well described by O(p^4) BChPT and we find sigma=37(8)(6) MeV for the sigma-term at the physical point. Using the nucleon mass to set the scale we obtain a Sommer parameter of r_0=0.501(10)(11) fm.Comment: 26 pages, 11 figures, 5 tables. Version to appear in NPB with a few more details on the fit parameter

    Plasmonic-organic hybrid (POH) modulators for OOK and BPSK signaling at 40 Gbit/s

    Get PDF
    We report on high-speed plasmonic-organic hybrid Mach-Zehnder modulators comprising ultra-compact phase shifters with lengths as small as 19 my m. Choosing an optimum phase shifter length of 29 my m, we demonstrate 40 Gbit/s on-off keying (OOK) modulation with direct detection and a BER < 6 x 10 -4. Furthermore, we report on a 29 my m long binary-phase shift keying (BPSK) modulator and show that it operates error-free (BER < 1 x 10 -10) at data rates up to 40 Gbit/s and with an energy consumption of 70 fJ/bit
    • …
    corecore