单圈T函数输出序列的稳定性研究

k-错线性复杂度是衡量序列稳定性的重要指标,该文对单圈T函数按位输出序列的k-错线性复杂度进行了深入研究,利用序列线性复杂度的多项式求解法和Chan Games算法,分析得到了当输入规模n=2tt时,单圈T函数按位输出序列k-错线性复杂度的分布,并进一步给出了该序列的k-错线性复杂度曲线。     

单圈 T-函数的 2-adic 复杂度和 1-错 2-adic 复杂度

研究了由 上单圈T-函数所导出权位序列的2-adic复杂度,设 为整数, 。结论表明,第 权位序列2-adic复杂度的上界为 。另外,讨论了与所有单圈 T-函数所导出第 权位序列相对应的2-adic整数的分布,分布情况说明这个上界是可以达到的。最后,研究了权位序列的1-错2-adic复杂度。研究结果表明对所有 ,权位序列 的1-错2-adic 复杂度都与其2-adic复杂度相同。     

2n-周期二元序列的3-错误序列分布

线性复杂度和k- 错线性复杂度是度量密钥流序列密码强度的重要指标。为了更好地研究序列的随机性,该文通过将序列的k-错线性复杂度的计算转化为求Hamming重量最小的错误序列的方法,讨论了序列不同k-错线性复杂度条件下对应的k-错误序列的分布情况。基于Games-Chan算法,该文给出了线性复杂度为2n的2n-周期二元序列的3错误序列的计数公式,计算机编程验证了该文方法的正确性。     

Fp上pn-周期序列的1-错线性复杂度

周期序列的线性复杂度和k-错线性复杂度是衡量密钥流序列随机性的两个重要指标.该文给出了Fp上pn-周期的序列所有可能的1-错线件复杂度的值以及具有给定1-错线性复杂度的序列个数.更进一步,该文给出了Fp上pn-周期的序列1-错线性复杂度的期望.     

单圈T函数输出序列k-错线性复杂度研究

该文对单圈T函数输出序列的k-错线性复杂度进行了深入研究,利用多项式理论和Chan Games算法,分析得到了当n=2t时,单圈T函数输出序列线性复杂度的n个下降点及其对应位置的k-错线性复杂度,并给出了k-错线性复杂度的分布和k-错线性复杂度曲线。     

确定周期为P n的二元序列k-错复杂度曲线的快速算法

设计了一个确定周期为P^n的二元序列k-错复杂度曲线的算法,这里p为素数,并且2是模P^2的一个本原根。该算法分别推广了魏-白-肖和魏-董-肖计算二元P^n周期序列线性复杂度与k-错复杂度的算法。     

确定GF(qm)上周期为2n的二元序列的2-adic复杂度的快速算法

2-adic复杂度是衡量流密码系统安全性能的一个重要指标.本文证明了周期为2n的二元序列的2-adic复杂度的计算可以规约为两个周期为n的二元序列的2-adic复杂度的计算,这里n是正整数.通过结合一些已知算法,可以有效地确定某些特殊周期二元序列的2-adic复杂度的上界.     

确定周期为p^n的二元序列的k—错线性复杂度的一个算法

本文给出了确定周期为p^n的二元序列的k-错线性复杂度的一个算法，这里p为素数，2为模p2的一个本原根。     

基于猫群优化算法的2~n周期优秀二元序列的研究与分析

密码学上强的序列不仅应该具有高的线性复杂度而且线性复杂度应该稳定,该文称此类序列为优秀序列。猫群优化算法是一种智能的全局优化搜索算法,能够根据给定的合理条件,自动生成所希望得到的结果。该文通过设计合理有效的适应度函数和恰当的参数选择,将猫群优化算法用于求解优秀序列,得到了周期N为32,64,128,256,512,1024等,错误数k小于等于N/4的二元优秀序列。并且结合大量实验数据,分析推测周期为N的二元优秀序列k-错线性复杂度满足规律LCk(S)￡N-2k+1。     

周期为pm的广义割圆序列的(p−1)/2-错线性复杂度

 周期为p^m的广义割圆序列具有很高的线性复杂度。该文通过改变序列的特征集,构造了一类周期相同的错误序列,确定了序列的k-错线性复杂度。结果表明,该类序列的(p−1)/2-错线性复杂度不超过p^m−1,这比该序列的线性复杂度低得多。因此,该类序列没有达到足够的安全作为密钥流生成器。     

k-error linear complexity of q-ary sequence of period p2

Based on element statistics in a matrix,a new efficient computing method for computing the k-error linear complexity of q-ary sequence of period p²was proposed,where p,q were odd primes and q modulo p²was primitive.A general result and a concrete proof were showed.To verify the correctness of the result,two kinds of q-ary sequence of period p²were illustrated.Because the new method does not need iterative calculation and when it is implemented by program and compared with existing algorithms,the results show that the proposed new algorithm is significantly more efficient in calculating k-error linear complexity of q-ary sequence of period p².     

THE 2-ERROR LINEAR COMPLEXITY OF 2^n-PERIODIC BINARY SEQUENCES WITH LINEAR COMPLEXITY 2^n -1

Linear complexity and k-error linear complexity of the stream cipher are two important standards to scale the randomicity of keystreams. For the 2n -periodicperiodic binary sequence with linear complexity 2n 1and k = 2,3,the number of sequences with given k-error linear complexity and the expected k-error linear complexity are provided. Moreover,the proportion of the sequences whose k-error linear complexity is bigger than the expected value is analyzed.     

Computing the k-error joint linear complexity of binary periodic multisequences

Complexity measures for multisequences over finite fields, such as the joint linear complexity and the k-error joint linear complexity, play an important role in cryptology. In this paper we study a fast algorithm, presented by Venkateswarlu A, to computer the k-error joint linear complexity of a binary periodic multisequence. In this paper, the aim is mainly to complement the theoretical derivation and proof of the existing algorithm. Moreover, our algorithm reduces computation.     

随机周期序列☆错线性复杂度的期望上界

周期序列的k错线性复杂度是衡量流密码系统的安全性能的一个重要指标。本文给出了周期序列k错线性复杂度上界的一个更强的结果,从而给出了几种不同情形下随机周期序列k错线性复杂度的期望的上界。特别地,还给出了周期N=pv,随机周期序列满足一定条件时1错线性复杂度的期望更紧的结果。     

Oxidative-gravimetric porosimetry of macroporous silicon

A simple nondestructive method to find the internal surface area, porosity, pore diameter, and pore density in macroporous silicon with through channels is suggested and tested. The porosity p is determined from the mass loss upon anodizing, and the surface area per unit volume, S _v , from the mass of SiO₂ formed on the pore surface upon thermal oxidation. The relations are given for calculation of the average pore diameter d and pore density N from the obtained S _v and p. Dependences of the specific surface area and porosity on the resistivity of initial n-Si in the range ρ = 3–25 Θ cm have been studied for samples with ordered and self-organized “lattices” of macropores. The obtained values are within the limits p = 27–50%, S _v = 2800–6000 cm²/cm³, d = 1.9–6.5 μm, and N = 1.4?10 × 10⁶ cm^?2, in agreement with the data fumished by microscopy.     

费马商构造的二元序列的线性复杂度

We determined the linear complexity of a family of p² -periodic binary threshold sequences and a family of p² -periodic binary threshold sequences constructed using the Legendre symbol, both of which are derived from Fermat quotients modulo an odd prime p . If 2 is a primitive element modulo p² , the linear complexity equals to p² -p or p²-1, which is very close to the period and it is large enough for cryptographic purpose.     

New encoding scheme of polar codes

The ’polar coding’ proposed by Dr. Ar kan can achieve the symmetric capacity of binary-input discrete memoryless channels (B-DMC). The generator matrix of polar codes is GN=BNFn for N=2n , BN was a permutation matrix. In the article it was realized with an interleaver, so the matrix production of GN was avoided; then the generator matrix was just determined by the matrix Fn which was constructed with three sub-matrixes of Fn-1 and one 2N-1 order zero matrix, it was deal with fast Hadamard transform (FHT) algorithm. The complexity of the new scheme was reduced sharply, and an iterative algorithm also can be used. The example showed that when N=8, complexity of the encoding scheme was just 16 which is obviously less than that of original encoding scheme 36.     

A 4<Emphasis Type="Italic">H</Emphasis>-SiC<Emphasis Type="Italic">p-i-n</Emphasis> diode fabricated by a combination of sublimation epitaxy and CVD

The possibility of fabricating heavily doped (N _a ?N _d ≥ 1 × 10¹⁹ cm_?3) p⁺-4H-SiC layers on CVD-grown lightly doped n-4H-SiC layers by sublimation epitaxy has been demonstrated. It is shown that a Au/Pd/Ti/Pd contact, which combines a low specific contact resistance (～2 × 10^?5 Ω cm²) with high thermal stability (up to 700°C), is the optimal contact to p-4H-SiC. The p-n structures obtained are used to fabricate packaged diodes with a breakdown voltage of up to 1400 V.     

Zone melting of indium phosphide

Bulk indium phosphide crystals have been prepared by zone melting with dislocation densities 104 ≤ N_d ≤ 105 cm^-2. The residual impurity level in nominally undoped crystals and the dopant distribution in Cd-, Sn- and Ge-doped zone melted ingots, as revealed by spark source mass spectrometric analyses, indicate a strong interaction between segregation at the solid/liquid interface and vapor transport. The effective distribution coefficients for Sn and Ge in zone melted InP are k_e(Sn) = 0.3 and k_e(Ge) = 0.4. The free electron concentration measured in the middle section of nominally undoped ingots is N_D-N_A = 1.9 × 10¹⁵ cm^-3 corresponding to a Hall mobility Μ_e = 3263 cm^2V-1sec^-l.