一种新型的缩控生成器

将缩减生成器与一种新型的钟控生成器组合构成了一种新型的伪随机序列生成器—缩控生成器,它是由两个三元的线性反馈移位寄存器(LFSR)构成。文章讨论了这种新型的缩控序列的周期,线性复杂度,符号分布及1,2-重量复杂度等密码学性质。分析结果表明,这种缩控序列具有大的周期,大的线性复杂度,符号分布也比较均衡,而且当LFSR级数很大时,缩控序列能够有效地抵抗B-M算法的攻击,适合于流密码系统中的应用。     

二维缩控生成器的构造与分析

论文基于三元伪随机序列,将钟控生成器和缩减生成器结合进行二维输出,构成一种新型伪随机序列生成器—二维缩控生成器,由其生成的二维缩控序列具有大周期和高线性复杂度,能够抵抗诸如B-M算法等综合算法攻击,且证明了序列游程长度为1或2,数据率为8/9,符号分布基本平衡等性质。因此,二维缩控生成器适合在流密码系统中应用。     

扩散输出序列的构造与分析

基于钟控、缩减生成器的构造思想,结合个别元素控制扩大输出的方式构造了一种新型伪随机序列生成器—扩散输出生成器。分析得到其生成序列—扩散输出序列的周期、线性复杂度及游程分布。文中进一步改变扩散输出组,得到一组伪随机序列,分析得到相应序列的周期和线性复杂度,实现对扩散输出生成器的拓展.     

一种A5流密码算法的设计实现

A5算法是一种利用伪随机数和非线性运算实现的流密码,它是求和生成器和钟控移位寄存器的组合,其线性复杂度大于两种生成器线性复杂度,加密速度快,适合无线突发信道。     

钟控密钥流生成器及其密码性能

提出了一种新的钟控密钥流生成器,由3个移位寄存器组成：两个被钟控的线性反馈移位寄存器A和B,一个提供钟控信息的非线性反馈移位寄存器C。设A、B和C的长度分别为l1、l2和l3。移位寄存器A和B的钟控信息由从移位寄存器C选取的两个比特串提供,移位的次数分别是两个比特串的汉明重量。研究了该生成器的周期、线性复杂度和k错线性复杂度,分析了这种密钥流生成器的安全性。     

LSRg[d,k]—互钟控序列

本文引进LSR_g[d,k]—互钟控序列模型,作为文献[1]中下标序列的具体实现,讨论了LSR_g[d,k]—互钟控序列的极小多项式,周期和线性复杂度等特点,给出了一批周期大,线性复杂度高的二元序列。     

F_q上钟控序列的线性复杂度

分析讨论了F_q上一类钟控序列的周期和线性复杂度。     

采样攻击的最短采样距分析

采样攻击是针对序列密码的一种攻击方法。该文对本原线性反馈移存器 (LFSR)序列的采样攻击方法进行了研究,给出了采样距与被采序列和采出序列的线性复杂度之间的制约关系,给出了能使采出序列的线性复杂度小于被采序列的线性复杂度的最短采样距,给出了能成功实施采样攻击需要的最少已知明文量,并据此分析了对本原LFSR序列进行采样攻击的实际可行性,证明了只有当本原LFSR的级数很小时,该方法才可能有实用价值。     

采样攻击的最短采样距分析

采样攻击是针对序列密码的一种攻击方法。该文对本原线性反馈移存器（LFSR）序列的采样攻击方法进行了研究,给出了采样距与被采序列和采出序列的线性复杂度之间的制约关系,给出了能使采出序列的线性复杂度小于被采序列的线性复杂度的最短采样距,给出了能成功实施采样攻击需要的最少已知明文量,并据此分析了对本原LFSR序列进行采样攻击的实际可行性,证明了只有当本原LFSR的级数很小时,该方法才可能有实用价值。     

一类具有良好特性的二元周期序列

本文利用m-序列和前馈序列的特性提出了一种新的生成器。这种生成器所生成的序列具有大的周期和线性复杂度,并且具有良好的伪随机特性。     

Linear complexity of a type of clock-controlled sequence

A new type of cascaded clock-controlled system is proposed. There are r+1 linear feedback shift registers (LFSRs) of length n in the system if the degree of cascade connection is r. It is proved that for an rth degree cascade the output sequences have linear complexity n Sigma /sub i=0//sup r/ (2/sup n/-1)/sup i/, period (2/sup n/-1)/sup r+1/ and good statistical properties. Such a model can generate key stream sequences of stream ciphers in computer applications.<>     

多值“加法型”组合生成器分析

文中运用信息论原理对多值“加法型”组合生成器序列进行分析，得到钟控序列与输出序列的互信息为零的结论，证明了钟控输入与输出序列之间互信息是输出序列长度的严格递增函数，进而对控选逻辑序列设计进行分析。     

On the linear complexity of nonlinearly filtered PN-sequences

Binary sequences of period 2/sup n/-1 generated by a linear feedback shift register (LFSR) whose stages are filtered by a nonlinear function, f, are studied. New iterative formulas are derived for the calculation of the linear complexity of the output sequences. It is shown that these tools provide an efficient mechanism for controlling the linear complexity of the nonlinearly filtered maximal-length sequences.     

Edit distances and probabilities for correlation attacks onclock-controlled combiners with memory

A theoretical framework for correlation attacks based on edit distances and edit probabilities on binary keystream generators consisting of clock-controlled shift registers combined by a function with memory is introduced. Recursive algorithms for efficient computation of the proposed many-to-one string edit distances and statistically optimal edit probabilities are derived for both constrained and unconstrained irregular clocking. The distances and probabilities are based on mutually correlated linear transforms of input and output sequences in the corresponding regularly clocked combiner with memory. Linear transforms can also incorporate linear models of clock-controlled shift registers. The complexity of the recursive algorithms is exponential in the memory size of the input linear transform which can be considerably smaller than the memory size of combining function. This is demonstrated for a special type of combiners with memory based on a time-varying memoryless function. In addition, a decimation method for reducing the memory size of the input linear transform is proposed. The design criteria with respect to the introduced correlation attacks are also discussed     

自相关性和线性复杂度的关系

自相关性和线性复杂度是衡量序列伪随机性质的两个独立的指标.针对周期为2^<em>n的伪随机序列,本文首次指出了自相关性和线性复杂度之间存在的一个关系.该关系可应用于以下两个方面:(1)由序列的线性复杂度来估计/确定序列的自相关函数值;(2)通过线性复杂度来检验给定序列族的互相关性质.进一步的,针对一类周期为2^<em>n的伪随机序列,我们指出这类序列的自相关函数值和线性复杂度以及k-错线性复杂度存在着关系.     

Computing the error linear complexity spectrum of a binary sequence of period 2/sup n/

Binary sequences with high linear complexity are of interest in cryptography. The linear complexity should remain high even when a small number of changes are made to the sequence. The error linear complexity spectrum of a sequence reveals how the linear complexity of the sequence varies as an increasing number of the bits of the sequence are changed. We present an algorithm which computes the error linear complexity for binary sequences of period /spl lscr/=2/sup n/ using O(/spl lscr/(log/spl lscr/)/sup 2/) bit operations. The algorithm generalizes both the Games-Chan (1983) and Stamp-Martin (1993) algorithms, which compute the linear complexity and the k-error linear complexity of a binary sequence of period /spl lscr/=2/sup n/, respectively. We also discuss an application of an extension of our algorithm to decoding a class of linear subcodes of Reed-Muller codes.     

GF(3)上新型自缩控序列的周期与线性复杂度

Self-Shrinking Control (SSC) sequences are a class of important pseudo-random sequences, and pseudo-random sequences are widely used in many fields, such as communication encryption, recoding technology. In these applications, sequences are usually required to have large periods and high linear complexity. In order to construct pseudo-random sequences with higher period and higher linear complexity, a new SSC sequence model based on the m-sequence in GF (3) is constructed, the period and the linear complexity of the generated sequence are studied by using finite domain theory, this model greatly improves the period and the linear complexity of the generated sequence, and obtains a more accurate upper bound value of the linear complexity of the generated sequence. Thus, the anti-attack ability and security performance of the generated sequence in communication encryption are improved.     

ANALYSIS OF THE MUTUAL INFORMATION BETWEEN INPUT AND OUTPUT OF A CLASS OF CLOCK-CONTROLLED SEQUENCES

In this paper, the mutual information between clock-controlled input and output sequences is discussed. It is proved that the mutual information is a strictly monotone increasing function of the length of output sequence, and its divergent rate is gaven.     

随机周期序列☆错线性复杂度的期望上界

周期序列的k错线性复杂度是衡量流密码系统的安全性能的一个重要指标。本文给出了周期序列k错线性复杂度上界的一个更强的结果,从而给出了几种不同情形下随机周期序列k错线性复杂度的期望的上界。特别地,还给出了周期N=pv,随机周期序列满足一定条件时1错线性复杂度的期望更紧的结果。