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.     

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。     

布尔函数的代数免疫性与设计准则

本文讨论了布尔函数的重量与代数免疫性之间的关系,给出了判断布尔函数是否有低次零化子的一个充分条件,并对由几类传统的构造方法所获得的布尔函数的代数免疫性进行了分析.     

递归构造多个具有最优代数免疫度的平衡布尔函数

代数免疫度是针对代数攻击而提出来的一个新的密码学概念.要能够有效地抵抗代数攻击,密码系统中使用的布尔函数必须具有平衡性、较高的代数次数、较高的非线性度和较高的代数免疫度等.为了提高布尔函数的密码学性能,通过布尔函数仿射等价的方法,找出了所有具有最优代数免疫度的三变元布尔函数.由这些具有最优代数免疫度的三变元非线性布尔函数,递归构造了一类代数免疫度最优、代数次数较高的平衡布尔函数.给出了这类布尔函数非线性度的一个下界,偶数变元时,其下界严格大于Lobanov给出的下界.     

低汉明重量序列的分布

数n的汉明重量是指n的二进制字符串表达式中数字1的个数,用Ham(n)来表示.低汉明重量序列在密码系统和编码理论中有非常广泛的应用.本文建立了低汉明重量数的序列表达式,并且利用指数和的上界以及Erd?s-Turán不等式证明低汉明重量序列的均匀分布性质,从而确保密码算法的随机性和运算效率.     

布尔“复合函数”的Walsh循环谱和自相关函数

本文利用布尔随机变量联合分布的分解式给出了布尔“复合函数”和某布尔函数符合率的分解算式,由此求得了布尔“复合函数”的 Walsh循环谱和自相关函数的计算公式,公式清楚地表明了“复合”所得布尔函数的 Walsh循环谱与起“复合”作用的函数和被“复合”的各函数所有线性组合的 Walsh循环谱之间的关系、“复合”所得布尔函数的自相关函数与起“复合”作用的函数谱和被“复合”的各函数的谱及相关函数之间的关系,这两个公式在布尔函数的密码学性质研究中会有广泛的应用.     

代数图递归迭代函数系与开集条件（英文）

本文研究R上一类代数图递归迭代函数系的开集条件与代数参数β之间的关系.我们证明若图递归迭代函数系满足开集条件且递归图是几何型的,则βs必是一个代数整数,其中s为图递归迭代函数系不变集的最大的Hausdorff维数.     

布尔函数的相关免疫与相对平衡性

平衡性和相关免疫性是函数的两个重要密码特性 ,但目前对两者之间的关系还没有得到很好地研究 .本文拟对布尔函数的平衡性和相关免疫性之间的关系作一些探讨 ,引进相对平衡性的概念 ,讨论相对平衡与通常的平衡概念的关系 ,得到布尔函数的关于相关免疫性和平衡性的一个充要条件     

有限域上低差分置换的计算与构造

低差分置换是对称密码算法的重要组件,最近屈等先后提出了优先函数、优先布尔函数的概念,并用之构造4-差分置换.构造了一些具有较少项数的优先布尔函数,将交换法中的布尔函数推广为F_(2~n)到F_4的映射,进一步研究了广义的交换构造,构造了三类新的4-差分置换,并计算了它们的非线性度.     

汉明距离矩阵的研究

汉明距离矩阵Ds是由测量定义在F_s~q：={0,1,…,q-1}^s上的码字的汉明距离的元素构成.汉明距离矩阵Ds可以由递归的形式表示出来.利用汉明距离矩阵Ds的递归公式求得了矩阵D_s所有特征根以及特征向量.在文章的最后还得出-cDs的Schur指数形的所有特征根.如果c〉0的话,-cDs的Schur指数形的所有特征根都大于零,从而-cDs的Schur指数形是正定的.     

具有最优代数免疫度的2~m个变量的对称Boolean函数

本文给出了2m个变量的对称Boolean函数f具有最优代数免疫度AI2m(f)=2m-1的一个充分必要条件.由此得到一个递归公式,从而构造出全部具有最优代数免疫度的2m个变量的对称Boolean函数(m2).最后证明了这样的Boolean函数的个数为3·2m.     

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.     

Linear codes from vectorial Boolean power functions

In this paper, three classes of binary linear codes with few weights are proposed from vectorial Boolean power functions, and their weight distributions are completely determined by solving certain equations over finite fields. In particular, a class of simplex codes and a class of first-order Reed-Muller codes can be obtained from our construction by taking the identity map, whose dual codes are Hamming codes and extended Hamming codes, respectively.     

Basic Theory in Construction of Boolean Functions with Maximum Possible Annihilator Immunity

So far there is no systematic attempt to construct Boolean functions with maximum annihilator immunity. In this paper we present a construction keeping in mind the basic theory of annihilator immunity. This construction provides functions with the maximum possible annihilator immunity and the weight, nonlinearity and algebraic degree of the functions can be properly calculated under certain cases. The basic construction is that of symmetric Boolean functions and applying linear transformation on the input variables of these functions, one can get a large class of non-symmetric functions too. Moreover, we also study several other modifications on the basic symmetric functions to identify interesting non-symmetric functions with maximum annihilator immunity. In the process we also present an algorithm to compute the Walsh spectra of a symmetric Boolean function with O(n²) time and O(n) space complexity. We use the term “Annihilator Immunity” instead of “Algebraic Immunity” referred in the recent papers [3–5, 9, 18, 19]. Please see Remark 1 for the details of this notational change     

Symmetric chains,Gelfand–Tsetlin chains,and the Terwilliger algebra of the binary Hamming scheme

The de Bruijn–Tengbergen–Kruyswijk (BTK) construction is a simple algorithm that produces an explicit symmetric chain decomposition of a product of chains. We linearize the BTK algorithm and show that it produces an explicit symmetric Jordan basis (SJB). In the special case of a Boolean algebra, the resulting SJB is orthogonal with respect to the standard inner product and, moreover, we can write down an explicit formula for the ratio of the lengths of the successive vectors in these chains (i.e., the singular values). This yields a new constructive proof of the explicit block diagonalization of the Terwilliger algebra of the binary Hamming scheme. We also give a representation theoretic characterization of this basis that explains its orthogonality, namely, that it is the canonically defined (up to scalars) symmetric Gelfand–Tsetlin basis.     

Duality between bent functions and affine functions

A Boolean function in an even number of variables is called bent if it is at the maximal possible Hamming distance from the class of all affine Boolean functions. We prove that there is a duality between bent functions and affine functions. Namely, we show that affine function can be defined as a Boolean function that is at the maximal possible distance from the set of all bent functions.     

Boolean Functions: Degree and Support

In this paper we establish some properties about Boolean functions that allow us to relate their degree and their support. These properties allow us to compute the degree of a Boolean function without having to calculate its algebraic normal form. Furthermore, we introduce some linear algebra properties that allow us to obtain the degree of a Boolean function from the dimension of a linear or affine subspace. Finally we derive some algorithms and compute the average time to obtain the degree of some Boolean functions from its support.     

New families of balanced symmetric functions and a generalization of Cusick,Li and Stǎnicǎ’s conjecture

In this paper we provide new families of balanced symmetric functions over any finite field. We also generalize a conjecture of Cusick, Li, and Stǎnicǎ about the non-balancedness of elementary symmetric Boolean functions to any finite field and prove part of our conjecture.     

Construction of rotation symmetric Boolean functions with optimal algebraic immunity and high nonlinearity

Recent research shows that the class of rotation symmetric Boolean functions is potentially rich in functions of cryptographic significance. In this paper, based on the knowledge of compositions of an integer, we present two new kinds of construction of rotation symmetric Boolean functions having optimal algebraic immunity on either odd variables or even variables. Our new functions are of much better nonlinearity than all the existing theoretical constructions of rotation symmetric Boolean functions with optimal algebraic immunity. Further, the algebraic degree of our rotation symmetric Boolean functions are also high enough.     

Binary linear codes from vectorial boolean functions and their weight distribution

Binary linear codes with good parameters have important applications in secret sharing schemes, authentication codes, association schemes, and consumer electronics and communications. In this paper, we construct several classes of binary linear codes from vectorial Boolean functions and determine their parameters, by further studying a generic construction developed by Ding et al. recently. First, by employing perfect nonlinear functions and almost bent functions, we obtain several classes of six-weight linear codes which contain the all-one codeword, and determine their weight distribution. Second, we investigate a subcode of any linear code mentioned above and consider its parameters. When the vectorial Boolean function is a perfect nonlinear function or a Gold function in odd dimension, we can completely determine the weight distribution of this subcode. Besides, our linear codes have larger dimensions than the ones by Ding et al.’s generic construction.