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关于m序列的自旋转缩减序列 总被引:10,自引:0,他引:10
本文介绍m序列的自旋转缩减序列;讨论了它的整齐的代数性质和良好的密友学性质,作为实用,本文提出了一种具人少量存储和判别的旋转缩减序列链接方案。 相似文献
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本文试图应用二元域上的数学方法,对m序列的倒序列进行较详细的分析,提出通过采样方法来获得倒序列的基本思想,推导并证明两个结论。最后给出m序列与其倒序列之间的关系和一个实例。 相似文献
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本文给出了一种产生m序列的分离式结构,对于特征多项式为(1+x~q+x~p)形式的m序列,利用该结构,只需增加少量门电路,即可将速率提高q倍并且不用更换或增加存贮元件。 相似文献
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一种基于同级m序列的非线性序列的产生方法 总被引:2,自引:0,他引:2
提出了一种由同一n级线性反馈移位寄存器的φ(2~n-1)/n种不同m序列构造一个非线性序列的新方法,可增加序列的线性复杂度。通过计算机模拟,发现该序列有尖锐的自相关特性以及近似于白噪声的频谱特性,是一种良好的伪随机序列,可用作密钥序列。 相似文献
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近年来随着多媒体技术和网络技术的广泛应用,数字水印越来越重要,在此首先分析了数字水印的意义,接着阐述了m序列产生的原因,以及利用Matlab产生的m序列。由于m序列的随机性,保证了数据的安全性,最后给出了Matlab仿真实验。 相似文献
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m序列的移位相加特性 总被引:2,自引:0,他引:2
讨论了m序列的移位相加特性,介绍了一种对给定的γ和η计算λ使序列三项式{ak η} {ak γ}={ak λ}成立的方法。无需给出m序列,只需通过产生m序列的本原多项式的互反多项式以及关于模p^n-1的分圆陪集就可以获得全部序列三项式。 相似文献
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求分圆陪集首元的新算法 总被引:2,自引:0,他引:2
本文首先指出了分圆陪集首元与序列密码之间的联系,然后给出了一个求分圆陪集首元的新算法,该算法比已有的算法要快。最后本文还推出了分圆陪集首元的一些特性。 相似文献
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本文探讨了无记忆组合函数的非线性与相关免疫性之间的关系,利用Walsh交换,研究了广义相关免疫函数的频谱特征,并且讨论了Bent函数的广义相关免疫阶数。 相似文献
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三大密码体制:对称密码、公钥密码和量子密码的理论与技术 总被引:7,自引:1,他引:6
随着信息技术的飞速发展,信息安全与通信保密日益重要与突出,密码技术是信息安全技术的核心。文中概括介绍了国内外三大密码体制(对称密码、公钥密码和量子密码)的理论与技术及其现状,分析了它们的发展趋势,重点探讨了分组密码的主要设计技术和量子密钥的产生与分发,最后对三大体制进行了比较。 相似文献
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For pseudo-random generators where one or several LFSRs are combined by a memoryless function, it is known that the output sequences are correlated to certain LFSR-sequences whose correlation coefficients c
t
satisfy the equation
i
c
2
i
= 1. In this paper it is proved that a corresponding result also holds for generators whose LFSRs are connected to a combiner with memory.If correlation probabilities are conditioned on side information, e.g., on known output digits, it is shown that new or stronger correlations may occur. This is exemplified for the summation cipher with only two LFSRs where such correlations can be exploited in a known plaintext attack. A cryptanalytic algorithm is given which is shown to be successful for LFSRs of considerable length and with arbitrary feedback connection.A preliminary version of this paper was presented at Eurocrypt '90, May 21–24, Århus, Denmark, and has appeared in the proceedings, pp. 204–213. 相似文献
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Guan Jie Liu Jiandong 《电子科学学刊(英文版)》2006,23(3):410-412
A linearization attack on the Key Stream Generator (KSG) of the modified Eo algorithm proposed by Hermelin [Proceedings of ICISC'99, Springer LNCS 1787, 2000, 17-29] is given in this paper. The initial value can be recovered by a linearization attack with O(2^60.52) operations by solving a System of Linear Equations (SLE) with at most 2^20.538 unknowns. Frederik Armknecht [Cryptology ePrint Archive, 2002/191] proposed a linearization attack on the KSG olEo algorithm with O(2^70.341) operations by solving an SLE with at most 2^24.056 unknowns, so the modification proposed by Hermelin reduces the ability or E0 to resist the linearization attack by comparing with the results ofFrederik Armknecht. 相似文献
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In this paper, we study an E0-like combiner with memory as the keystream generator. First, we formulate a systematic and simple
method to compute correlations of the FSM output sequences (up to certain bits). An upper bound of the correlations is given,
which is useful to the designer. Second, we show how to build either a uni-bias-based or multi-bias-based distinguisher to
distinguish the keystream produced by the combiner from a truly random sequence, once correlations are found. The data complexity
of both distinguishers is carefully analyzed for performance comparison. We show that the multi-bias-based distinguisher outperforms
the uni-bias-based distinguisher only when the patterns of the largest biases are linearly dependent. The keystream distinguisher
is then upgraded for use in the key-recovery attack. The latter actually reduces to the well-known Maximum Likelihood Decoding
(MLD) problem given the keystream long enough. We devise an algorithm based on Fast Walsh Transform (FWT) to solve the MLD
problem for any linear code with dimension L and length n within time O(n+L⋅2
L
). Meanwhile, we summarize a design criterion for our E0-like combiner with memory to resist the proposed attacks. 相似文献
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信源平衡编码及其在流密码中的应用 总被引:1,自引:0,他引:1
本文对离散无记忆信源给出了一种编码方法,它使编码后信源输出有着最好的平衡性,即0与1的数目最大程度地接近.对等长编码,本文给出的方法是步优的;对基于Huffman码的平衡编码,在保持平均码长不变的情况下,本文给出的方法使0与1的平衡性达到最优.因为一般信源字符的频率是一个统计数字.这里的平衡性也是从统计角度来说的.最后我们还讨论了这种平衡编码对流密码中的非线性组合器在防止相关攻击方面的防护作用. 相似文献