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1.
p元扩域上的快速乘法   总被引:1,自引:0,他引:1  
李银  陈恭亮  李建华 《通信学报》2009,30(11):101-105
基于剩余算术理论构造了一类F_p[x]上的项式PAPB,给出了该型不可约多项式的存在数量估计;然后,利用剩余算术和中国剩余定理,提出了一种模PAPB乘法的快速实现算法;最后给出结果分析.理论和实验结果表明,在一定条件下,给出算法的计算复杂度仅有O(k~(1.5)),优于常用模二项式乘法O(k~2)的计算复杂度.因此,该类多项式在最优扩域和椭圆曲线算法中有较好的应用前景.  相似文献   

2.
 针对具有低重量反馈多项式的比特搜索生成器(BSG),利用猜测确定攻击的思想提出了一种快速密钥恢复攻击。该算法基于BSG序列的差分构造特点,首先由截获的密钥流恢复出候选差分序列,然后用反馈多项式对候选差分序列进行校验,以此减少需要求解的L维线性方程系统的数量,从而大大减少了算法所需的复杂度。理论分析和仿真结果表明,对于反馈多项式的重量小于10的BSG,该算法明显优于现有的攻击方法。特别地当反馈多项式的重量为3时,该算法能够将最好的攻击结果O(L320.5L)降低到O(L20.5L)。  相似文献   

3.
采样攻击的最短采样距分析   总被引:1,自引:0,他引:1  
采样攻击是针对序列密码的一种攻击方法.该文对本原线性反馈移存器 (LFSR)序列的采样攻击方法进行了研究,给出了采样距与被采序列和采出序列的线性复杂度之间的制约关系,给出了能使采出序列的线性复杂度小于被采序列的线性复杂度的最短采样距,给出了能成功实施采样攻击需要的最少已知明文量,并据此分析了对本原LFSR序列进行采样攻击的实际可行性,证明了只有当本原LFSR的级数很小时,该方法才可能有实用价值.  相似文献   

4.
采样攻击是针对序列密码的一种攻击方法。该文对本原线性反馈移存器(LFSR)序列的采样攻击方法进行了研究,给出了采样距与被采序列和采出序列的线性复杂度之间的制约关系,给出了能使采出序列的线性复杂度小于被采序列的线性复杂度的最短采样距,给出了能成功实施采样攻击需要的最少已知明文量,并据此分析了对本原LFSR序列进行采样攻击的实际可行性,证明了只有当本原LFSR的级数很小时,该方法才可能有实用价值。  相似文献   

5.
将缩减生成器与一种新型的钟控生成器组合构成了一种新型的伪随机序列生成器—缩控生成器,它是由两个三元的线性反馈移位寄存器(LFSR)构成。文章讨论了这种新型的缩控序列的周期,线性复杂度,符号分布及1,2-重量复杂度等密码学性质。分析结果表明,这种缩控序列具有大的周期,大的线性复杂度,符号分布也比较均衡,而且当LFSR级数很大时,缩控序列能够有效地抵抗B-M算法的攻击,适合于流密码系统中的应用。  相似文献   

6.
本文首先论述了确保线性递归序列具有最大线性复杂度的若干条件的乘积,探讨了具有不可约极小多项式(本原或非本原)序列的乘积。其次证明了在GF(q)上,任意条最大长度序列,只有当每条序列对应的极小多项式的次数各不相同且大于2时,其乘积才具有最大线性复杂度,并把这一结论推广到乘积序列的任意线性组合。最后论述m为正时,q~m-1本原因子理论。  相似文献   

7.
pmqn周期q元序列线性复杂度与k错复杂度的关系   总被引:3,自引:0,他引:3  
研究了q元周期序列线性复杂度和k错复杂度之间的关系,给出了k错复杂度严格小于线性复杂度的一个充要条件.当周期为N=pqn时,给出了使得LC(S+E)<LC(S)成立的错误多项式EN(x)的确切表达式,以及使得LCk(S)<LC(S)成立的最小的k值,即minerror(S)的值,结果表明minerror(S)与线性复杂度的重量密切相关;当周期为N=pmqn时,给出了使得LC(S+E)<LC(S)成立的用错误多项式EN(x)表达的一个充分条件.这里P为奇素数,q是素数且是一个模p2的本原根.  相似文献   

8.
混合图的有向k树多项式的产生和状态空间树   总被引:5,自引:0,他引:5  
引入了混合图G的有向K树多项式P(t_(F_1),……F_K)的状态空间树T的概念和算法SSTDKTP。提出了用分支-定界法产生P(t_(F_1),……,F_K)的一个新算法——算法DKTPCG。该算法简单,所得表达式十分紧凑。计算时间复杂度是O(men_l);空间复杂度对于堆栈是O[(n-k)(ke+n)],对于输出数组XE,YE,FL和NS是O(n_(df)),这里n_l和n_(df)分别是T的叶点和状态节点的数目。  相似文献   

9.
密码学意义上强的序列不仅应该具有足够高的线性复杂度,而且当少量比特发生改变时不会引起线性复杂度的急剧下降,即具有高的k~-错复杂度。该文以多项式的因式分解为主要工具研究了任意有限域GF(q)上,周期N与p互素以及N=p~v这两种情况下,计数函数N_(N,O)(C)的值,井给出了线性复杂度的数学期望E_(N,O)的值以及k~-错复杂度的数学期望E_(N,k)的一个有用的下界,这里p是有限域GF(q)的特征。  相似文献   

10.
本文着重对R.Rueppel关于“产生具有足够大线性复杂的序列”这篇论文进行了综述,并对其推论1作了进一步推广。通常,产生具有大的线性复杂度序列的一个方法,是将一个非线性函数f用于二元最长线性反馈移位寄存器(LFSR),当函数f表示为GF(2)上其变量乘积和的形式,则称f具有代数标准形式(ANY),在ANF中,f的非线性阶K是在一个乘积次中变量出现酌最高次数,众所周知,当非线性前馈函数f的阶为K时,则输出序列Z的线性复杂度的上限为其中~1L表示使用LFSR的长度,它表明了当函数f具有形式其中所有L个K阶项仅仅包含相邻的变量,且f’为级数不超过K-1次的任意函数,那么,产生的输出序列其线性复杂度的下限为此处L为素数,其证明利用了范德蒙到列式的性质。  相似文献   

11.
DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.  相似文献   

12.
This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel's.  相似文献   

13.
The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.  相似文献   

14.
Today, micro-system technology and the development of new MEMS (Micro-Electro-Mechanical Systems) are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.  相似文献   

15.
The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.  相似文献   

16.
From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.  相似文献   

17.
It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output(MIMO) communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.  相似文献   

18.
Waveguide multilayer optical card (WMOC) is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling & processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic (VB) language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.  相似文献   

19.
The effect of laser microbeam trapping the bioparticles has been appfied widely in the biology .However the micromechanism of the acting that realizes the laser-microbeam trapping bioparticles is still lacking. In this paper ,the act microchenism of the gradiant force of laser microbeam for the bioparticles is analysed by means of quantum theory ,The result accords with our experiment.  相似文献   

20.
Using multiple importance sampling (MIS) technique, the optical communication system performance affected by polarization-mode dispersion (PMD) and polarization-dependent loss (PDL) is simulated numerically. The power penalties and system outage probabilities are obtained for optical communication systems with on-off keying (OOK) or differential phase shift keying (DPSK) modulation. The simulation results show that DPSK always performs better than OOK. When the system has moderate PDL (about 1.5 dB), it is necessary to compensate effectively the fiber PMD in order to enhance the system tolerance to the PMD and PDL. However, the efficiency of PMD compensation will degrade rapidly when the PMD of the whole optical link drops into the low value.  相似文献   

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