基于Simulink的序列密码仿真研究

提出了利用Simulink对序列密码编码系统仿真的方法。根据基于移位寄存器产生伪随机序列的原理，使用Simulink的存储器模块模拟移位寄存器，以此为基础加上逻辑运算、双路选择等模块建立密钥序列生成器的仿真模型，并使用子系统技术，建立信息加（解）密系统的仿真模型。还以3种基本的序列模型m序列、前馈序列和钟控序列为例，给出了密钥序列生成器以及序列密码加（解）密系统的仿真设计。     

混沌序列与一类基于移位寄存器的非线性序列的性能比较

混沌序列与一类基于移位寄存器的非线性序列非线性前馈逻辑(Non-Linear Feed-ForwardLogic,NLFFL)序列都具有非线性、宽带类噪声、大的码族、长的周期且容易产生的特性,通过对它们在产生方式、相关性能、多址性能以及抗相关攻击能力等方面进行分析和仿真研究,说明混沌序列与该类非线性序列在性能上总体相当,但对于短周期序列(N1023),混沌序列的抗相关攻击、抗干扰能力更强,因此更具有实用价值。     

Nonsingularity of Feedback Shift Registers of Degree at Most Three over a Finite Field

As a kind of generators of pseudo-random sequences, the Feedback shift register (FSR) is widely used in channel coding, cryptography and digital communication. A necessary and sufficient condition for the nonsingularity of a feedback shift register of degree at most three over a finite field is established. Using the above result, we can easily determine the nonsingularity of a feedback shift register from the algebraic normal form of the corresponding feedback function.     

一类非线性扩频序列的构造及其性能分析

基于本原三项式线性函数,构造了一类非线性序列.首先根据非线性序列生成规律,借助逻辑代数理论,推导并提取了非线性序列特征函数,利用特征函数筛分作用,合成了非线性反馈函数,据此实现了非线性序列生成.最后,对该类非线性序列特性进行了分析和计算,并将其应用于直接序列码分多址通信系统(DS-CDMA)仿真实验中,结果表明该类非线性序列不仅具有理想的伪随机特性、良好的线性复杂度,还具有优于m序列、gold序列的误码率.     

二元给定序列非线性移位寄存器的综合与产生

依据非线性移位寄存器的原理，文中讨论二元给定序列非线性反馈移位寄存器的综合算法，用C语言编程．找到了产生该序列的非线性移位寄存器。借助EDA技术，以FPGA为硬件基础，经过设计优化构成定长序列和给定周期序列的伪随机序列发生器，并进行了仿真实验，用硬件实验证实了设计的合理性。     

Delayed versions of maximal-length linear binary sequences

Any delayed version of a linear binary sequence can be obtained from a suitable linear combination of the outputs of the feedback shift register which generates the sequence. A simple method is given for calculating the linear combination required to give a specified delayed version. The method involves polynomial long division, and is not restricted to short sequences.     

Minimal linear equivalent analysis of a variable-memory binarysequence generator

Starting from a memory-based nonlinear generator due to P.R. Geffe (1973), a binary sequence generator (MEM-BSG), consisting of three linear feedback shift registers and a variable memory, is defined and analyzed. The MEM-BSG is shown to be convenient for generating fast binary sequences of large period and linear complexity, which may be useful in spread-spectrum and cryptographic applications     

Mutually clock-controlled cipher keystream generators

Two keystream generators are described that use mutual clock control between a number of sequence generators. One is the T52e cipher, and the other uses three linear feedback shift registers. In the latter the register periods can lock together, giving an anomalously short period. Methods for avoiding this are described     

线性伪随机序列的综合与产生

研究了线性移位寄存器的综合问题，对于给定的二元周期序列，可以采用梅西算法实现序列的综合，用C语言编程，找到了产生该序列的最短线性移位寄存器。借助EDA技术，以EPLD为硬件基础，经过设计优化，构成了起始状态可预置、序列周期可改变的伪随机序列发生器，并进行了仿真实验，硬件实验证实了设计的合理性。     

Probability distribution of pseudorandom waveforms obtained from msequences

The letter discusses the probability distribution of pseudorandom waveforms obtained from m sequences by summing the digits stored in the feedback shift register which generates the sequence. A recurrence relation is given, valid for both the binary and nonbinary cases, which enables the probability distribution to be determined easily.     

二进神经网络非线性移位寄存器的综合

本文利用二进神经网络及其学习算法特点和对布尔函数的映射能力,设计了一个精巧的非线性移位寄存器的综合算法,同时得到序列非线性复杂度的移位寄存器的反馈布尔函数.此综合算法简单可靠,所需存储运算量小.     

Results on the nonlinear span of binary sequences

The problem of finding the length of a shortest feedback shift register that generates a given finite-length sequence is considered. An efficient algorithm for the determination of the span is proposed, that takes advantage of the special block structure of the associated system of linear equations. The span distribution of finite-length binary sequences is also studied.     

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.     

Information sources using chaotic dynamics

A sequence of binary random variables has found significant applications in modem digital communication systems. For such sequences, several kinds of linear feedback shift register sequences have been proposed. It is, however, well known in probability theory that the Bernoulli shift is a fundamental theoretic model of a sequence of independent identically distributed (i.i.d.) binary random variables. In this paper after reviewing fundamental subjects of chaotic dynamics, in particular a close relationship between information sources and Markov chains, we give the generation method of sequences of i.i.d. binary random variables using chaotic dynamics. Such a generation method is given as a sufficient condition composed of simple symmetric properties for some class of ergodic maps. Furthermore, we give the applications of such sequences: (1) to running-key sequences for stream cipher systems and (2) to a color image communication system through code-division multiple access channels and its extended version, a digital watermarking system. In addition, the performance of spread spectrum codes generated by a Markov chain is theoretically evaluated in asynchronous direct-sequence/code-division multiple access systems     

Design Algorithm of All-Optical Linear Feedback Shift Registers

We demonstrate an algorithm for the design and implementation of an all-optical linear feedback shift register (LFSR), based on optically controlled XOR gate and optical shift registers. The algorithm tackles the huge length of optical shift registers to produce controllable pseudorandom binary sequences (PRBS).     

一种更长周期m序列的实现方法

m序列即最长线性反馈移位寄存器序列,其随机特性与白噪声特性最为接近,是一种常用的信号形式,在信号分析和信号处理中具有重要的价值。为了产生随机性能良好的伪随机序列,进而生成较为理想的白噪声信号,满足一般通信系统的测试要求,文中从m序列的原理和构造方法出发,应用周期性变更线性反馈移位寄存器的反馈连接和初始状态的方法,提出了一种基于VHDL生成的具有更长周期m序列的新方案。给出了原理分析、系统设计及算法的仿真结果。     

Fast Correlation Attacks on the Summation Generator

The linear sequential circuit approximation method for combiners with memory is used to find mutually correlated linear transforms of the input and output sequences in the well-known summation generator with any number of inputs. It is shown that the determined correlation coefficient is large enough for applying a fast correlation attack to the output sequence to reconstruct the initial states of the input linear feedback shift registers. The proposed attack is based on iterative probabilistic decoding and appropriately generated low-weight parity-checks. The required output sequence length and the computational complexity are both derived. Successful experimental results for the summation generators with three and five inputs are obtained. Received 13 December 1996 and revised 7 October 1998     

Triple correlation analysis of m-sequences

It is demonstrated that the period of an m-sequence and the feedback function of the linear feedback shift register which generates it can be determined by the use of a triple correlation analysis technique.<>     

σ-LFSR序列极小多项式性质研究

σ-线性反馈移位寄存器(σ-LFSR)是基于字设计的,在安全性和效率上达到较好折衷的一种反馈移位寄存器。σ-LFSR输出序列的特征多项式为有限域上的矩阵多项式。该文利用有限域上矩阵多项式环的代数结构,给出了σ-LFSR输出序列极小多项式唯一的充分必要条件。     

Irreducible Polynomials Which Divide Trinomials Over GF (2)

The simplest linear shift registers to generate binary sequences involve only two taps, which corresponds to a trinomial over GF(2). It is therefore of interest to know which irreducible polynomials f(x) divide trinomials over GF(2), since the output sequences corresponding to f(x) can be obtained from a two-tap linear feedback shift register (with a suitable initial state) if and only if f(x) divides some trinomial t(x)=x^m+x^a+1 over GF(2). In this paper, we develop the theory of which irreducible polynomials do, or do not, divide trinomials over GF(2). Then some related problems such as Artin's conjecture about primitive roots, and the conjectures of Blake, Gao, and Lambert, as well as of Tromp, Zhang, and Zhao are discussed