具有2n线性复杂度的2n周期二元序列的3错线性复杂度

线性复杂度和k错线性复杂度是度量密钥流序列的密码强度的重要指标.通过研究周期为2n的二元序列线性复杂度,提出将k错线性复杂度的计算转化为求Hamming重量最小的错误序列.基于Games-Chan算法,讨论了线性复杂度为2n的2n周期二元序列的3错线性复杂度分布情况;给出了对应k错线性复杂度序列的完整计数公式, k=3,4.对于一般的线性复杂度为2n-m的2n周期二元序列,也可以使用该方法给出对应k错线性复杂度序列的计数公式.     

二元叠加码δ(n,d,k)的平均汉明距离和均方差

研究了二元叠加码δ(n,d,k)的平均汉明距离(Hamming distance)和它的均方差问题.利用δ(n,d,k)的定义和新构造的一个组合函数,获得了求二元叠加码δ(n,d,k)的平均汉明距离和它的均方差公式,并获得了它的平均汉明距离的界.     

一类4次旋转对称布尔函数的汉明重量和非线性度

旋转对称布尔函数在密码学中具有重要的应用价值.本文研究了一类特殊4次的旋转对称布尔函数的快速求值及其汉明重量的递归关系,通过将该函数分解成数个子函数,并利用这些函数的傅里叶变换值的递归关系,证明了其汉明重量与非线性度相等.本文的结果和处理指数和的方法对于进一步研究Cusick的一个猜想可能有帮助.     

第二类窃密信道中的组合数学方法

当信息在第二类窃密信道中传输时,线性码的广义汉明重量谱完全描述的它在该信道中的密码学特征.计算一个线性码的广义汉明重量谱是一个基本问题,首先提出了线性码的“最简基”的概念.在此基础上给出了一般线性码子码的几种计数公式,并给出了它们之间等价性的证明.     

基于广义分圆法的一类跳频序列族

平均汉明相关值是评价跳频序列族性能的一个重要参数.本文在Whiteman广义分圆法的基础上构造了一类新的跳频序列族,随后证明了其关于平均汉明相关界是最优的,并给出了各类汉明相关值的计算公式.     

一类马尔可夫序列最大值的极限律

主要研究一类马尔可夫序列{Xn,n≥0}的最大值的极限分布.导出了这类序列最大值和最小值的分布表达式,利用经典极值理论,建立了规范化最大值max{X0,X1,…,Xn}与i.i.d序列{ξn,n≥1}的规范化最大值max{1ξ,2ξ,…,ξn+1}具有相同极限律的条件.     

旋转对称逻辑公式的构造

给出了n=p_1~(a1)p_2~(a2)···p_(ωn)~(aωn)时已有方法计算长圈个数错误的反例,并得到了此情况下正确的长圈个数计算公式.研究了如何构造汉明重量为某个定值的旋转对称布尔函数.将旋转对称布尔函数引入到计量逻辑学中,提出了旋转对称逻辑公式的概念.找到了如何构造真度为某个定值的旋转对称逻辑公式的方法。     

两类三次旋转对称布尔函数的汉明重量和非线性度

旋转对称布尔函数是一类具有良好密码学性质的布尔函数,自被提出来就得到了学者们的广泛关注.本文研究了形如f(x)=∑n-1 i=0 xix1+ixm+1+i和ft(x)=∑n-1 i=0 xixt+ixm+i的两类三次旋转对称布尔函数的汉明重量及非线性度.通过对F_2~n进行分解,可将函数转化为特殊形式,使得求取函数的傅里叶变换变得相对容易.再利用汉明重量及非线性度与傅里叶变换之间的关系,求出了这两类函数的汉明重量和非线性度的计算公式.     

基于单模数线性同余方程组设计的公钥密码体系

本文基于MH-KPKC体系和HILL密码体系的构建思想,提出了基于单模数线性同余方程组设计的公钥密码体系.该体制无需利用超递增序列和贪心算法恢复明文.算例说明了该体制的可行性。     

二元叠加码M_q(n,k,d)码的平均汉明距离和均方差

根据二元叠加码(Binary Superimposed Code)M_q(n,k,d)的定义及有限域F_q上n维向量空间的k维子空间的维数性质定义了一个高斯组合函数,利用这个组合函数研究了M_q(n,k,d)码的平均汉明(Hamming)距离和它的均方差问题,给出了计算公式.     

The Hamming weight of the non-adjacent-form under various input statistics

The Hamming weight of the non-adjacent form is studied in relation to the Hamming weight of the standard binary expansion. In particular, we investigate the expected Hamming weight of the NAF of an n-digit binary expansion with k ones where k is either fixed or proportional to n. The expected Hamming weight of NAFs of binary expansions with large (≥ n/2) Hamming weight is studied. Finally, the covariance of the Hamming weights of the binary expansion and the NAF is computed. Asymptotically, these Hamming weights become independent and normally distributed. Communicated by Attila Pethő     

On Perfect Ternary Constant Weight Codes

We consider the space of ternary words of length n and fixed weight w with the usual Hamming distance. A sequence of perfect single error correcting codes in this space is constructed. We prove the nonexistence of such codes with other parameters than those of the sequence.     

The completion of optimal cyclic quaternary codes of weight 3 and distance 3

Designs, Codes and Cryptography - A cyclic $$(n,d,w)_q$$ code is a cyclic q-ary code of length n, constant weight w and Hamming distance at least d. The function $$CA_{q}(n,d,w)$$ denotes the...     

二元叠加码Mq(i:n,k,d)的检纠错性质

对于自然数i,d,k,n,0q(i:n,k,d)是一个基于有限域Fq上n维向量空间中子空间的相交关系的二元叠加码,研究了二元叠加码M_q(i:n,k,d)任意列之间的汉明距离,给出了它的检错性和纠错性.     

Constructions of optimal low-hit-zone frequency hopping sequence sets

In recent years, the study relating to low-hit-zone frequency hopping sequence sets, including the bounds on the Hamming correlations within the low hit zone and the optimal constructions, has become a new research area attracting the attention of many related researchers. In this paper, two constructions of optimal frequency hopping sequence sets with low hit zone have been employed, one of which is based on m-sequence while the other is based on the decimated sequences of m-sequence. Moreover, in the special case of \(k=n-1\), the construction based on the decimated sequences of m-sequence also yields low-hit-zone frequency hopping sequence sets with optimal periodic partial Hamming correlation property.     

5-Designs from the lifted Golay code over Z4 via an Assmus–Mattson type approach

Recently, Harada showed that the codewords of Hamming weight 10 in the lifted quaternary Golay code form a 5-design. The codewords of Hamming weight 12 in the lifted Golay code are of two symmetric weight enumerator (swe) types. The codewords of each of the two swe types were also shown by Harada to form a 5-design. While Harada's results were obtained via computer search, a subsequent analytical proof of these results appears in a paper by Bonnecaze, Rains and Sole. Here we provide an alternative analytical proof, using an Assmus–Mattson type approach, that the codewords of Hamming weight 12 in the lifted Golay code of each symmetric weight enumerator type, form a 5-design.Also included in the paper is the weight hierarchy of the lifted Golay code. The generalized Hamming weights are used to distinguish between simple 5-designs and those with repeated blocks.     

Notes on the value function

The properties satisfied by the value function are given. These properties can be used to study the generalized Hamming weight and the relative generalized Hamming weight of certain linear codes.     

The Weight Enumerator of Linear Codes over GF q m) Having Generator Matrix over GF q

We have the relationships between the Hamming weight enumerator of linear codes over GFq ^m which have generator matrices over GFq, the support weight enumerator and the -ply weight enumerator.     

Strongly regular graphs from reducible cyclic codes

Journal of Algebraic Combinatorics - Let p be a prime number. Reducible cyclic codes of rank 2 over $$\mathbb {Z}_{p^m}$$ are shown to have exactly two Hamming weights in some cases. Their weight...     

Lower bounds for codes correcting moderate-density bursts of fixed length with Lee weight consideration

Lee weight is more appropriate for some practical situations than Hamming weight as it takes into account magnitude of each digit of the word. In this paper, considering Lee weight, we obtain necessary lower bound over the number of parity checks to correct bursts of length b (fixed) whose weight lies between certain limits. We also obtain Lee weight bound for such type of moderate-density bursts with limited intensity.