共查询到19条相似文献,搜索用时 156 毫秒
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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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本文在文献「1」「2」的基础上研究了一阶相关免疫函数的计数问题,给出了非经的一介相关免疫函数计数的最新公式,从而也给出了一阶相关免疫函数计数的一个新的下界。 相似文献
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一阶相关免疫布尔函数的计数 总被引:4,自引:0,他引:4
本文研究了结构布尔函数的相关免疫性,得到了一大类满足一阶相关免疫的线性结构函数的计数并大大改进了一阶相关免疫函数的计数结果,得到了目前为止的最好下界。 相似文献
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H布尔函数的相关免疫性与重量的关系 总被引:1,自引:0,他引:1
将布尔函数的导数和与导数一起便可直接明确刻画布尔函数的重量而定义的e-导数一起作研究工具,深入到布尔函数取值的内部结构中去,讨论了在H布尔函数存在的一个大重量范围内,所有不同重量的H布尔函数的一阶、任意m阶相关免疫函数存在与否的问题。对存在m阶相关免疫性的H布尔函数,它的相关免疫阶数m与维数n的具体关系,以及m的最大值问题。给出了m阶相关免疫H布尔函数只存在于2种重量的H布尔函数中,其相关免疫阶数m的最大值为n-2,以及其余重量的H布尔函数中不存在二阶以上(包括二阶)相关免疫函数等一系列结果。同时,也给出了一些判断布尔函数相关免疫性的方法。 相似文献
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MIMO雷达波形集的互相关函数峰值越低,则正交性越好,波形分集增益越高。非循环互相关函数下界的研究有助于确定波形分集增益的极限值,对MIMO雷达波形设计与应用有重要意义。相位编码波形集是目前被研究最多的MIMO雷达波形集,对其相关函数下界的研究较为深入。本文对目前相位编码波形集相关函数各类下界的研究进行归纳总结,包括相关函数峰值旁瓣下界、相关函数积分旁瓣下界、互相关内积下界、互补序列相关函数下界四大类。相关函数峰值旁瓣下界是影响MIMO雷达波形分集增益的关键指标,其他类型的下界与相关函数峰值旁瓣下界之间存在潜在联系,这可能有助于相关函数峰值旁瓣下界的确定。不同波形数,不同码长的典型相位编码波形相关函数指标与下界的对比结果表明,目前已有下界都不够紧,尤其在波形数较多时。因此,MIMO雷达相位编码波形集相关函数下界仍是一个值得研究的开放问题。 相似文献
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In this paper, we consider the relationship between nonlinearity and correlation immunity of Boolean functions. In particular, we discuss the nonlinearity of correlation immune functions suggested by P. Camion et al. For the analysis of such functions, we present a simple method of generating the same set of functions, which makes it possible to construct correlation immune functions with controllable correlation immunity and nonlinearity. Also, we find a bound for the correlation immunity of functions having maximal nonlinearity. 相似文献
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Bent-function sequences 总被引:12,自引:0,他引:12
《IEEE transactions on information theory / Professional Technical Group on Information Theory》1982,28(6):858-864
In this paper we construct a new family of nonlinear binary signal sets which achieve Welch's lower bound on simultaneous cross correlation and autocorrelation magnitudes. Given a parametern withn=0 pmod{4} , the period of the sequences is2^{n}-1 , the number of sequences in the set is2^{n/2} , and the cross/auto correlation function has three values with magnitudesleq 2^{n/2}+1 . The equivalent linear span of the codes is bound above bysum_{i=1}^{n/4}left(stackrel{n}{i} right) . These new signal sets have the same size and correlation properties as the small set of Kasami codes, but they have important advantages for use in spread spectrum multiple access communications systems. First, the sequences are "balances," which represents only a slight advantage. Second, the sequence generators are easy to randomly initialize into any assigned code and hence can be rapidly "hopped" from sequence to sequence for code division multiple access operation. Most importantly, the codes are nonlinear in that the order of the linear difference equation satisfied by the sequence can be orders of magnitude larger than the number of memory elements in the generator that produced it. This high equivalent linear span assures that the code sequence cannot be readily analyzed by a sophisticated enemy and then used to neutralize the advantages of the spread spectrum processing. 相似文献
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Further Results of Cheating Immune Secret Sharing 总被引:3,自引:0,他引:3
ZHANG Jie~ 《中国邮电高校学报(英文版)》2004,11(4)
Cheating immune secret sharing in the unconditionally secure case are investigated in this paper.Constructionsof defining functions of cheating immune secret sharing on V_n are given,where n is any integer greater than 5.Further-more,the obtained defining functions have good cryptographic properties.The nonlinearity of them is 2~(n-1)-2~(n/2 1) whenn≡0(mod 4)and 2~(n-1)-2~((?)n/2」 2) otherwise.And thedegree is「n/4(?). 相似文献