共查询到18条相似文献,搜索用时 187 毫秒
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本文探讨了布尔"复合函数"G(f1,L,fk)的有关密码学性质,分别给出了布尔"复合函数"是平衡函数、m阶相关免疫函数、(n,l.m)弹性函数,m阶广义ε-相关免疫函数的条件及其满足严格雪崩准则的条件. 相似文献
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本文主要讨论了当n=2m+1(m1)时,n阶严格择多逻辑函数的代数正规形式中,所有的阶为k((n+1)/2kn-1)的非线性项都出现,从而从密码学角度来说,这种函数有好的密码学特征。 相似文献
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《中国无线电电子学文摘》1994,(5)
0153.2 94050038一类布尔函数的简化与应用/罗守山(北京邮电大学)11北京邮电大学学报一1994,17(2)一84~90 通过引人第三类布尔函数的概念,借助于感知器的识别理论,对布尔函数简化后的形式做出判断,并对感知器在n元输人下的(2z)n功能中的可分功能数做T估计.表2参7(北)1994, 从21(1)厂一68一722阶Hadamard矩j咋H:经m一l次Kronercker乘积可以得到一个2m阶Hadamard矩阵HZ坷文中给出了定理及定理证明.参3侧匕)017,TN911.8 94050039环面方程的定性分析与应用一例/周荣星,李华(西安电子科技大学)l/西安电子科技大学学报一1994,21(2)一168~172 … 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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作为密码学上的应用,由几个线性反馈移位寄存器及一个非线性组合函数组成的伪噪声发生器己被建议用作流式密码中的密钥流(running key)发生器,有时,这些密钥流发生器能够被对其子序列的(唯密文)相关攻击所破译。现介绍一类新的组合函数,它能提供较好的保密性以对抗这样的攻击。其保密性由在相关攻击中要同时考虑的序列的最小数目m+1所确定。并证明了这样的m阶相关免疫性的一个必要条件。且给出一个递归构遣方法,对任意的m和n,1≤m相似文献
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n元非奇异反馈函数的计数 总被引:1,自引:0,他引:1
李超 《信息安全与通信保密》1997,(3)
给出有限域GF(2~m)(2|m)上次数不超过3的n元非奇异反馈函数的简洁表达式,求出了这类饭函数的个数。 相似文献
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讨论了一阶相关免疫函数的结构、构造,根据文中的构造法,新下界具有形式g(n)2^2n-1,这里g(n)→∞(n→∞)。 相似文献
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Resilient functions over finite fields 总被引:3,自引:0,他引:3
Yupu Hu Guozhen Xiao 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2003,49(8):2040-2046
Resilient functions play an important role in the art of information security. In this correspondence, we discuss the existence, construction, and enumeration of resilient functions over finite fields. We show that, for each finite field GF(q) with q > 3, we can easily construct a large number of (q, n, 1, n - 1) resilient functions, most of which include mixing terms. We give a general structure for (q, m + 1, m, 1) resilient functions, and present an example which is not of this general structure. We prove that (q, m + 2, m, 2) resilient functions exist for any m such that 1 < m < q when q > 2. We prove that (q, m + t, m, t) resilient functions exist for any (m, t) such that 1 < m < q and 2 < t < q when q > 3. By making some simple generalizations of former results, we also provide some new methods for constructing resilient functions. 相似文献
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The scheme for the expansion of a 2-dimensional f.i.r. digital filter function into a sum of separable functions is generalised. Using the generalised procedure a m × m order filter function can be expressed in as many as m!n!/(|m?n| + 1)! ways. Further it is also proved that the number of terms in the expansion will be equal to the rank of the matrix. 相似文献
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A construction of resilient functions with high nonlinearity 总被引:10,自引:0,他引:10
Johansson T. Pasalic E. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2003,49(2):494-501
We provide a construction technique for multiple-output resilient functions F:F/sub 2//sup n//spl rarr/F/sub 2//sup m/ with high nonlinearity. The construction leads to the problem of finding a set of linear codes with a fixed minimum distance, having the property that the intersection between any two codes is the all-zero codeword only. This problem is considered, and existence results are provided. Moreover, the constructed functions obtain a nonlinearity superior to previous construction methods. 相似文献
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Shouxing Qu Tet Yeap 《Vehicular Technology, IEEE Transactions on》1999,48(3):765-781
Clarke's (1968) scattering model, one of the most widely accepted channel models for the land mobile environment, is a two-dimensional (2-D) model because of the assumption of horizontal traveling plane waves. By introducing a nonzero elevation angle of the arriving wave, a three-dimensional (3-D) model is more general and accurate, especially for the urban environment. Though the concept of the 3-D model has been proposed already, there is still a lack of satisfying results regarding the distribution of the elevation angle, from both theoretical analysis and field measurement, and the power spectral density (PSD) of the received signal. In this paper, a family of functions with two parameters, {m,n}, where m and n are positive integers, for both the symmetrical and asymmetrical probability density function (PDF) of the elevation angle (EA), is proposed. Among these functions, those with odd m and n lead to analytical solutions of the PSD of the received signal in addition to satisfying other requirements for a PDF of the EA previously proposed in literature. The PSDs in closed form associated with m and n equal to one and three are derived in particular, and the autocorrelation functions are obtained numerically. Since a family of functions rather than a single function is proposed for the PDF of the EA, it provides certain flexibility in application and covers a wide range of environments. Another contribution of this paper is a new expression which directly relates the PDF of the EA in the 3-D model to the PSD of the received signal 相似文献
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The main construction for resilient functions uses linear errorcorrecting codes; a resilient function constructed in this way is said to be linear. It has been conjectured that if a resilient function exists, then a linear function with the same parameters exists. In this note we construct infinite classes of nonlinear resilient functions from the Kerdock and Preparata codes. We also show that linear resilient functions having the same parameters as the functions that we construct from the Kerdock codes do not exist. Thus, the aforementioned conjecture is disproved.kResearch supported by NSF Grant CCR-9121051. 相似文献
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Algebraic immunity for cryptographically significant Boolean functions: analysis and construction 总被引:13,自引:0,他引:13
Carlet C. Dalai D.K. Gupta K.C. Maitra S. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2006,52(7):3105-3121
Recently, algebraic attacks have received a lot of attention in the cryptographic literature. It has been observed that a Boolean function f used as a cryptographic primitive, and interpreted as a multivariate polynomial over F/sub 2/, should not have low degree multiples obtained by multiplication with low degree nonzero functions. In this paper, we show that a Boolean function having low nonlinearity is (also) weak against algebraic attacks, and we extend this result to higher order nonlinearities. Next, we present enumeration results on linearly independent annihilators. We also study certain classes of highly nonlinear resilient Boolean functions for their algebraic immunity. We identify that functions having low-degree subfunctions are weak in terms of algebraic immunity, and we analyze some existing constructions from this viewpoint. Further, we present a construction method to generate Boolean functions on n variables with highest possible algebraic immunity /spl lceil/n/2/spl rceil/ (this construction, first presented at the 2005 Workshop on Fast Software Encryption (FSE 2005), has been the first one producing such functions). These functions are obtained through a doubly indexed recursive relation. We calculate their Hamming weights and deduce their nonlinearities; we show that they have very high algebraic degrees. We express them as the sums of two functions which can be obtained from simple symmetric functions by a transformation which can be implemented with an algorithm whose complexity is linear in the number of variables. We deduce a very fast way of computing the output to these functions, given their input. 相似文献