• Title/Summary/Keyword: 차분값

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Power Analysis Attacks on Blinding Countermeasure against Horizontal CPA (수평적 상관관계 분석에 안전한 블라인딩 대응기법에 대한 전력 분석 공격)

  • Lee, Sangyub;Kim, Taewon;Kim, HeeSeok;Hong, Seokhie
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.25 no.4
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    • pp.727-738
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    • 2015
  • Until recently, power analysis is one of the most popular research issues among various side channel analyses. Since Differential Power Analysis had been first proposed by Kocher et al., various practical power analyses correspond with software/hardware cryptographic devices have been proposed. In this paper, we analyze vulnerability of countermeasure against power analysis exploiting single power trace of public cryptographic algorithm. In ICICS 2010, Clavier et al. proposed Horizontal Correlation Analysis which can recover secret information from a single exponentiation trace and corresponding countermeasures. "Blind operands in LIM", one of their countermeasures, exploits additive blinding in order to prevent leakage of intermediate value related to secret information. However, this countermeasure has vulnerability of having power leakage that is dependant with the message known by an adversary. In this paper, we analyzed vulnerabilities by three attack scenarios and proved them by practical correlation power analysis experiments.

The Influence of the Aspect Ratio on the Natural Frequency of the Composite Laminated Plates (복합적층판의 고유진동수에 대한 형상비의 영향)

  • Han, Bong-Koo;Suck, Ju-Won
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.1 no.2
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    • pp.14-19
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    • 2010
  • Theories for advanced composite structures are too difficult for such design engineers for construction and some simple but accurate enough methods are necessary. The senior author has reported that some laminate orientations have decreasing values of $D_{16}$, $B_{16}$, $D_{26}$ and $B_{26}$ stiffnesses as the ply number increases. For such plates, the fiber orientations given above behave as specially orthotropic plates and simple formulas developed by the senior author. Most of the bridge and building slabs on girders have large aspect ratios. For such cases further simplification is possible by neglecting the effect of the longitudinal moment terms(Mx) on the relevant partial differential equations of equilibrium. In this paper. the influence of the aspect ratio on the natural frequency of the composite laminated plates is studied and it is concluded that the method used is sufficiently accurate for engineering purposes.

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Numerical Analysis for the Pullout Behavior and Failure Mechanism of Ground Anchor (그라운드 앵커의 인발거동 및 파괴메카니즘에 대한 수치해석)

  • Park, Byung-Soo;Shim, Do-Sik
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.2
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    • pp.69-76
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    • 2010
  • This study is an numerical study of predicting the behavior of anchor embedded in weathered rocks, subjected to uplift loads, about ultimate pullout capacity and the failure mechanism. Factors influencing the behavior of anchors were investigated by reviewing the data about in-situ anchor tests performing numerical modelling with changing the bondage length of anchor, diameter of anchor body and diameter of tendon, and by correlations between those factors were evaluated to apply them to predict the behavior of anchors. As results of numerical analysis, a linear relationship between bondage length, diameter of anchor body and diameter of tendon with ultimate pullout capacity was obtained on the one hand, from the result of numerical analysis changing the Young's modulus of weathered rock, this parameter was found to influence to load-displacement and ultimate pullout capacity within the range of 10%, which was not so significant to affect.

Accurate and Robust Computations of Gas-Liquid Two-Phase Flows Part 2: Preconditioned Two-Phase Schemes for All Speeds (액체-기체 2상 유동장의 정확하고 강건한 해석 Part 2: 전 마하수 영역 해석을 위한 예조건화)

  • Ihm, Seung-Won;Kim, Chong-Am
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.1
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    • pp.17-27
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    • 2009
  • Two-phase RoeM and AUSMPW+ schemes are preconditioned for the simulation of all Mach number flows, which are generally of interest for many gas-liquid two-phase application problems, because of large speed of sound in liquid region and low speed of sound in mixture or gas region. Conventional characteristic based schemes lose their accuracy or robustness in low Mach number flows, because their numerical dissipation terms are scaled by speed of sound, which is too large compared with local velocity magnitude in a low Mach region. All speed versions of RoeM and AUSMPW+ reflect the eigenvalues of the preconditioned governing system, which have the same order of magnitude even in low Mach number region. From the asymptotic analysis, it is observed that the discretized system by the developed schemes is consistent with the continuum system in the incompressible limit. The numerical results show the accurate and robust behavior of the proposed shcemes for all speed two-phase flows.

PREPROCESSING OF THE GPS RAW DATA FOR THE PRECISION ORBIT DETERMINATION BY DGPS TECHNIQUE (DGPS 방식에 의한 위성의 정밀궤도 결정을 위한 GPS 원시 자료 전처리)

  • 문보연;이정숙;이병선;김재훈;박은서;윤재철;노경민;최규홍
    • Journal of Astronomy and Space Sciences
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    • v.19 no.2
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    • pp.163-172
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    • 2002
  • This article investigates the problem of data preprocessing for the precision orbit determination (POD) of low earth orbit satellite using GPS .aw data. Several data preprocessing algorithms have been developed to edit the GPS data automatically such that outlier deletion, cycle slip identification and correction, and time tag error correction. The GPS data are precisely edited for the accuracy of POD. Some methods of data preprocessing are restricted to the rate of the collections of the pseudorange and carrier phase measurements. This study considers the preprocessing efficiency varied with the rate, the quality of receiver and the altitude of the satellite's orbit. We also propose the proper methods in accordance with the rate for single frequency and dual frequency receivers.

The Characteristic and Control of Contaminant Transport through the Subsurface of Nanjido Landfill (난지도 매립장 지반을 통한 오염이동 특성과 제어)

  • 장연수;이광열
    • Journal of the Korean Society of Groundwater Environment
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    • v.1 no.1
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    • pp.1-5
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    • 1994
  • The contaminant migration through the subsurface of Nanjido landfill is studied using a 2-D finite element model of contaminant transport. The leachate mounding caused by the installation of partial slurry wall around the pheriperal area of the Landfill is analysed using the finite difference model of groundwater flow. Model parameters were validated using in-situ concentration data and the behavior of the transport next 30 years is predicted. The sensitivities of chloride concentration by the change of model parameters, e.g. leachate mounding in the Landfill and the dispersivity are analysed. The results of the analyses show that the maximum chloride concentration level near Han River caused by the leachate of Nanjido Landfill would be 1488mg/1 and comes 17 years after the landfill closure. Increase of the leachate concentration is caused by the increase of both the leachate mounding and the dispersivity. However, the rate of concentration increase becomes higher with the rise of leachate mounding level, while it tends to converge a certain concentration with the increase of the dispersivity.

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The Numerical Modeling Study for the Simultaneous Flow of Leachate and LFG in Kimpo Landfill (수도권 매립지에서 침출수-가스의 동시 유동 해석을 위한 전산 모델링 연구)

  • 성원모;박용찬;이광희
    • Journal of the Korean Society of Groundwater Environment
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    • v.6 no.2
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    • pp.101-106
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    • 1999
  • Open dump of refuse causes groundwater and soil contamination by leachate and air pollution by LFG(Landfill Gas). In this paper, in order to perform a study about reduction of high leachate and LFG collection & control, using a 3-D, 2-phase, transient FDM model, the analysis of simultaneous flow of leachate and LFG has been carried out. In present numerical analysis it is assumed that 58 percents of LFG will evaporate to the ambient air and the recharge rate of a landfill be 12 percent of the average precipitation per year. All other data were excerpted at the point of 1995 when three refuse layers had been buried. From numerical analysis we concluded that maximum head value is approximately 26 mH2O<-에이치투오 (2.52 atm) in the center of the system and that installing venting trench plays an important role in landfill stabilization. Evan with the assumption of three layers constructed and low recharge rate applied, it is found that cumulative leachate and LFG productions will be 15.1 million 세제곱미터, 5.58 billion 세제곱미터, respectively after 40 years.

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Optimization Techniques for Soil Parameters used in Axisymmetric Nonlinear Consolidation Analysis (축대칭 비선형 압밀해석을 위한 지반정수값의 최적화기법)

  • 김윤태;이승래
    • Geotechnical Engineering
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    • v.12 no.4
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    • pp.131-144
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    • 1996
  • In order to accelerate the rate of consolidation settlement and to gain a required shear strength for a given soft clay deposit, the preloadina technique combined with a vertical drainage system has been widely applied. Even if a sophisticated numerical analysis technique is applied to solve the consolidation behavior of drainage-installed soft deposits, the actual field behavior is often different from the behavior predicted in the design state due to several uncertainties involved in soil properties, numerical modelling, and measuring system. In this paper, two back-analysis schemes such hs simplex and BFGS methods have been implemented in an a Bisymmetric consolidation program, AXICON which considers the variation of compressibility and permeability during the consolidation process. Utilizing the program, one might be able to appropriately predict the subsequent consolidation behavior from the measured data in an early stage of consolidation of drainage-installed soft deposits.

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A Comparative Study of Genetic Algorithm and Mathematical Programming Technique applied in Design Optimization of Geodesic Dome (지오데식 돔의 설계최적화에서 유전알고리즘과 수학적계획법의 비교연구)

  • Lee, Sang-Jin;Lee, Hyeon-Jin
    • Proceeding of KASS Symposium
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    • 2008.05a
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    • pp.101-106
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    • 2008
  • This paper describes a comparative study of genetic algorithm and mathematical programming technique applied in the design optimization of geodesic dome. In particular, the genetic algorithm adopted in this study uses the so-called re-birthing technique together with the standard GA operations such as fitness, selection, crossover and mutation to accelerate the searching process. The finite difference method is used to calculate the design sensitivity required in mathematical programming techniques and three different techniques such as sequential linear programming (SLP), sequential quadratic programming(SQP) and modified feasible direction method(MFDM) are consistently used in the design optimization of geodesic dome. The optimum member sizes of geodesic dome against several external loads is evaluated by the codes $ISADO-GA{\alpha}$ and ISADO-OPT. From a numerical example, we found that both optimization techniques such as GA and mathematical programming technique are very effective to calculate the optimum member sizes of three dimensional discrete structures and it can provide a very useful information on the existing structural system and it also has a great potential to produce new structural system for large spatial structures.

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Side-Channel Attacks on LEA with reduced masked rounds (축소 마스킹이 적용된 경량 블록 암호 LEA-128에 대한 부채널 공격)

  • Park, Myungseo;Kim, Jongsung
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.25 no.2
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    • pp.253-260
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    • 2015
  • The side-channel attack is widely known as an attack on implementations of cryptographic algorithms using additional side-channel information such as power traces, electromagnetic waves and sounds. As a countermeasure of side channel attack, the masking method is usually used, however full-round masking makes the efficiency of ciphers dramatically decreased. In order to avoid such a loss of efficiency, one can use reduced-round masking. In this paper, we describe a side channel attack on the lightweight block cipher LEA with the first one~six rounds masked. Our attack is based on differentials and power traces which provide knowledge of Hamming weight for the intermediate data computed during the enciphering of plaintexts. According to our experimental result, it is possible to recover 25 bits of the first round key in LEA-128.