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若布尔函数的输出不泄漏其输入值的有关信息,则称该函数是相关免疫的.这类函数在计算机保密应用中用途广泛.本文研究了m阶相关免疫函数的构造和计数问题,给出了两种新的构造方法.进一步,将这两种新构造方法与Seigenthaler,杨义先,Camion,Seberry以及温巧燕等人的构造方法进行了比较,证明了本文中的构造方法实际上推广了这些文献中的结论.利用本文中的构造方法,既可直接构造任意阶的相关免疫函数,又可根据已知的相关免疫函数来构造新的相关免疫函数.另外,基于新的构造方法,改进了m阶相关免疫的平衡函数的计数下界. 相似文献
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本文提出了一种构造Bent函数的新方法,依此可定出大量在实用中很重要的Bent函数;本文还对2次Bent函数进行仿射分类,证明了2次Bent函数仅有2类,并定出了其每一类中的代表函数;最后,本文研究了Bent函数的一阶广义相关免疫性。 相似文献
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具有紧支采样函数的子波空间采样定理 总被引:1,自引:0,他引:1
从复制核Hilbert空间的观点出发,本文详细地讨论了子波空间采样定理,提出了子波空间推广的主尺度函数概念,证明了它是构造紧支子波空间采样函数的充要条件,从而得到具有紧支采样函数的子波空间采样定理。本文还详细地研究了推广的主正交尺度函数的性质,证明了紧支的推广主正交尺度函数所对应的子波函数仅有一阶消失矩,采样函数的紧支性和所对应的子波函数的光滑性是不可兼得的。 相似文献
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T-函数由于具有计算速度快、密码学性质良好等特点而得到广泛应用,先后用于构造分组密码、Hash函数和流密码。单圈T-函数可以用来代替流密码中的线性反馈移位寄存器,逐渐用来构建新的流密码体制。文中介绍了单圈T-函数的性质,概括了长周期单圈T-函数已知的三种类型,推广了T-函数的定义,有利构造新的长周期单圈T-函数。并总结了关于单圈T-函数值得进一步研究的几个问题。 相似文献
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针对非线性最大长度移位寄存器反馈函数难以构造问题,本文提出了一种基于母函数构造非线性最大长度移位寄存器反馈函数方法.首先,我们阐述了母函数模3分类法,证明了各类母函数新的特征状态集,提取了母函数的特征式;其次,根据特征式对母函数的筛分特性合成了非线性m子序列移位寄存器反馈函数;最后,分析了该移位寄存器生成的伪随机序列,对其自相关值和线性复杂度进行了大量搜索.结果一致表明该序列不仅具有良好的周期特性、平衡特性、游程特性,还具有尖锐的自相关特性和理想的线性复杂度. 相似文献
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On bent and semi-bent quadratic Boolean functions 总被引:4,自引:0,他引:4
Charpin P. Pasalic E. Tavernier C. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2005,51(12):4286-4298
The maximum-length sequences, also called m-sequences, have received a lot of attention since the late 1960s. In terms of linear-feedback shift register (LFSR) synthesis they are usually generated by certain power polynomials over a finite field and in addition are characterized by a low cross correlation and high nonlinearity. We say that such a sequence is generated by a semi-bent function. Some new families of such function, represented by f(x)=/spl Sigma//sub i=1//sup (n-1)/2/c/sub i/Tr(x(2/sup i/)+1), n odd and c/sub i//spl isin/F/sub 2/, have recently (2002) been introduced by Khoo et al. We first generalize their results to even n. We further investigate the conditions on the choice of c/sub i/ for explicit definitions of new infinite families having three and four trace terms. Also, a class of nonpermutation polynomials whose composition with a quadratic function yields again a quadratic semi-bent function is specified. The treatment of semi-bent functions is then presented in a much wider framework. We show how bent and semi-bent functions are interlinked, that is, the concatenation of two suitably chosen semi-bent functions will yield a bent function and vice versa. Finally, this approach is generalized so that the construction of both bent and semi-bent functions of any degree in certain range for any n/spl ges/7 is presented, n being the number of input variables. 相似文献
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次数最大的平衡相关免疫函数的构造 总被引:1,自引:0,他引:1
Maitra和Sarkar于1999年提出了一种递归构造n元平衡相关免疫布尔函数的方法。该文给出了一种新的递归构造方法,构造出非线性度很高的n元m阶n- m-1次的平衡相关免疫函数。与原构造方法相比,该文构造方法得到的函数性质相同,数量更大。 相似文献
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Some new results showing the classification of Boolean functions of order n, n ? 5, under the Rademacher?Walsh transform, together with the operation of spectral translation, are examined. It is found that there are 48 prototype functions, of which 21 are threshold functions. Examination of the canonic spectral forms of these threshold functions shows that a threshold function may be identified uniquely for n ? 5, under a sum-of-squares criterion. 相似文献
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Some properties of rotation symmetric orbits were proposed in n dimensional vector space over finite field of characteristic 2,a matrix on the distributions of number pairs such as 00,01 and 11 was defined,and a new characterization of 2-resilient rotation symmetric functions was introduced.Constructions of rotation symmetric 2-resilient Boolean functions with 4t-1 number of variables were presented by modifying the support of the linear rotation symmetric functions,such as f0(x)=x1+x2+…+xn,where n=4t-1.At last,an example was demonstrated to introduce the spirit of the proposed method to construct 2-resilient rotation symmetric functions with 4t-1 number of variables. 相似文献
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From the motivation of algebraic attacks on stream and block ciphers,the concept of algebraic immunity(AI) of a Boolean function was introduced and studied extensively.High algebraic immunity is a necessary condition for resisting algebraic attacks.In this paper,we give some lower bounds on the algebraic immunity of Boolean functions.The results are applied to give lower bounds on the AI of symmetric Boolean functions and rotation symmetric Boolean functions.Some balanced rotation symmetric Boolean functions with their AI near the maximum possible value「n/2」are constructed. 相似文献
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一种新的扩散混合机制 总被引:2,自引:0,他引:2
本文针对扩散混合新机制扩压函数,提出了它的基本设计原则。引入了级连布尔函数的概念,给出并证明了它的一些性质,在此基础上提出了单比特扩压函数的一种构造方法,并给出了一个具体的具有良好密码学性能且结构简单易于软硬件实现的单比特扩压函数实例。 相似文献