三值m序列及其发生器的综合

本文描述了三值序列和三值m序列,提出了三值序列发生器和三值m序列发生器的设计方法。基于三值D触发器,设计了三值m序列发生器。对其所产生的序列验证表明,符合三值m序列的三条伪随机性质[9]。     

一种新型的交流电源信号发生器的设计

介绍了交流电源信号发生器的基本原理,阐述了国内外有关交流电源信号发生器设计的基本方法,基于可编程逻辑器件（CPLD）设计实现了交流电源信号发生器,并给出了仿真及实验波形。     

混沌跳频序列发生器的FPGA实现

本文根据单峰映射产生混沌序列极易被攻击的特点,采用高维的混沌系统来设计混沌跳频序列发生器.针对n维非线性数字滤波器产生序列的周期和分布特性,我们在系统结构上作了相应的设计,并最终应用FPGA(现场可编程门阵列)技术实现混沌跳频序列发生器.跳频序列发生器产生序列的测试结果表明,序列具有均匀分布,大的线性复杂度,汉明相关服从均值为L/q的高斯分布,因此混沌跳频序列发生器的设计是成功的.     

基于ispLSI器件的线阵CCD时序发生器设计

本文介绍了线阵CCD的时序逻辑，分析了时序发生器的组成原理及工作过程，并详细论述了基于ispLSI1016、利用Synario对CCD时序发生器进行的设计、编译，且进行了功能仿真。     

多机协同攻击逻辑的蚁群算法研究

针对协同空战中多目标的攻击逻辑问题,首先以攻击优势和目标战役价值为准则建立攻击逻辑决簸模型,然后结合蚁群算法的思想,分析了蚁群算法的状态转移、局部调整和全局调整规则,给出攻击逻辑的求解算法,最后以具体仿真算例,证明文中给出的算法能有效地完成多机协同攻击逻辑决策任务。     

CPLD在图像采集卡中的应用

文章用VerilogHDL语言在Altera公司的MAXPLUS-II集成软件环境下设计了一种基于CPLD(复杂可编程逻辑器件)的图像采集卡中的地址发生器和总线切换逻辑,实现了CPLD芯片EPM9320RC208地址发生器和总线切换的功能。     

流密码典型分析方法及实例

流密码的设计与分析在现代密码学中占有重要地位。简要介绍了流密码分析的基本原理和模型,主要包括：折中攻击、猜测和决定攻击、相关攻击、最佳仿射攻击、代数攻击和边信道攻击。然后基于Mathematica平台,使用简易密钥流发生器为测试对象,对其中的折中攻击、猜测和决定攻击及相关攻击进行了仿真实现。通过实验,揭示了流密码算法的一个重要设计原则：避免内部状态演变的线性性以及输出序列统计性质的偏向性。最后对流密码分析方法给予了总结和展望。     

NSPK协议的Spin模型检测

NSPK协议是一个经典的认证密码协议.通过建立该协议的Promela模型,采用线性时序逻辑描述模型性质,并用模型检测工具Spin进行验证,进而生成入侵者的攻击序列.     

基于亚稳态的QDI逻辑随机路径切换方法研究

 基于QDI异步逻辑与四相双轨协议相结合时数据路径平衡的特性,能够实现双轨编码输入点的随机切换,从而达到各数据路径的平均功耗平衡,消除数据与功耗之间关联的目的.然而,现有的利用多路复用器实现数据路径随机切换的方法存在抗攻击弱点,削弱了系统的抗能量分析攻击能力.为此,我们提出了基于亚稳态的QDI随机路径切换方法:采用两级切换结构,利用亚稳态发生器和亚稳态滤波器,实现数据路径组和数据路径的随机切换.仿真结果表明,基于亚稳态的QDI随机路径切换方法具有良好的功耗平衡特性,能够很好的抵消由于寄生电容和负载电容差异造成的旁路信息泄露,从而极大地提高系统的安全性.     

高频虚拟仪器的FPGA实现

论述基于FPGA技术兼有数字信号发生器和逻辑分析仪功能的虚拟仪器的设计方案及具体实现方法。FPGA集成了串口通信、分频、RAM读写、数据采集、信号发生器等功能模块,具有成本低,频率高,修改扩充方便、抗干扰性好等特点。利用VBWindows编程技术实现友好的虚拟仪器面板。     

The constructions of almost binary sequence pairs with three-level correlation based on cyclotomy

In this paper, a new class of almost binary sequence pair with a single zero element is presented. The almost binary sequence pairs with three-level correlation are constructed based on cyclotomic numbers of order 2, 4, and 6. Most of them have good correlation and balance property, whose maximum nontrivial correlation magnitudes are 2 and the difference between the numbers of occurrence of +1’s and ′-1’s are 0 or 1. In addition, the corresponding binary sequence pairs are investigated as well and we can also get some kinds of binary sequence pairs with optimum balance and good correlation.     

An analysis of the structure and complexity of nonlinear binary sequence generators

A method of analysis is presented for the class of binary sequence generators employing linear feedback shift registers with nonlinear feed-forward operations. This class is of special interest because the generators are capable of producing very long "unpredictable" sequences. The period of the sequence is determined by the linear feedback connections, and the portion of the total period needed to predict the remainder is determined by the nonlinear feed-forward operations. The linear feedback shift registers are represented in terms of the roots of their characteristic equations in a finite field, and it is shown that nonlinear operations inject additional roots into the representation. The number of roots required to represent a generator is a measure of its complexity, and is equal to the length (number of stages) of the shortest linear feedback shift register that produces the same sequence. The analysis procedure can be applied to any arbitrary combination of binary shift register generators, and is also applicable to the synthesis of complex generators having desired properties. Although the discussion in this paper is limited to binary sequences, the analysis is easily extended to similar devices that generate sequences with members in any finite field.     

最佳屏蔽二进序列偶在低/零相关区中的应用研究

将最佳屏蔽二进序列偶应用于低/零相关区中,提出最佳屏蔽低/零相关序列偶集的概念,给出了3种构造低/零相关序列偶集的方法,即奇数长最佳屏蔽二进序列偶与Hadamard矩阵相结合组成ZCZ(零相关区)序列集,偶数长最佳屏蔽二进序列偶与改造后的Hadamard矩阵组成LCZ(低相关区)序列集,以及任意长度最佳屏蔽二进序列偶与正交矩阵构成ZCZ序列集。利用这些构造方法,扩展了原有低/零低相关区存在的长度范围,扩大了序列集的容量,可以更好地满足工程应用的需要。     

复制生成序列的自相关函数研究

介绍了以二进制码为复制信息,用平移复制生成序列的方法。讨论了复制生成序列的性质和复制生成序列的自相关函数的性质。依据序列的复制特性,给出了一个复制生成序列自相关函数的计算公式,并给出了自相关函数值为零的一个充要条件,及相应的数学证明。最后讨论了Paley顺序的离散Walsh函数的自相关函数。     

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     

可分差集偶与几乎最佳二元序列偶的研究

在雷达、声纳等工程领域中具有良好相关性的序列得到广泛应用.几乎最佳二元序列偶具有良好的自相关性,它的异相自相关函数只有一点不为零.为了进一步研究几乎最佳二元序列偶,提出了一类新的区组设计——可分差集偶,研究了可分差集偶的性质,给出了可分差集偶与几乎最佳二元序列偶的对应关系,应用可分差集偶的性质得到了几乎最佳二元序列偶存在的必要条件.为应用可分差集偶这种区组设计的方法研究几乎最佳二元序列偶提供了理论依据.     

Linear models for a time-variant permutation generator

A keystream generator, known as RC4, consisting of a permutation table that slowly varies in time under the control of itself, is analyzed by the linear model approach. The objective is to find linear relations among the keystream bits that hold with probability different from one half by using the linear sequential circuit approximation method. To estimate the corresponding correlation coefficients, some interesting correlation properties of random Boolean functions are derived. It is thus shown that the second binary derivative of the least significant hit output sequence is correlated to 1 with the correlation coefficient close to 15·2^-3n where n is the variable word size of RC4. The output sequence length required for the linear statistical weakness detection is then around 64ⁿ/225. The result can be used to distinguish RC4 from other keystream generators and to determine the unknown parameter n, as well as for the plaintext uncertainty reduction if n is small     

组合生成器的多线性相关攻击

本文对组合生成器提出了一种相关攻击方法,这种方法同时利用组合生成器输入与输出之间多个线性关系的信息来恢复密钥,我们从理论上证明了该方法可有效的减少攻击所需的数据量.特别地,我们将这种方法用于攻击"蓝牙组合生成器",使攻击复杂度得到显著降低.     

Bent-function sequences

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 parameternwithn=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.     

蓝牙组合生成器相关系数的计算方法

蓝牙组合生成器是蓝牙协议中使用的密钥流生成算法,它是一个带4 bit记忆的非线性组合生成器,其输入和输出之间相关系数的表示和计算是一个困难的问题,而这是对这种生成器进行相关性分析和相关攻击的基础.该文对一般的带记忆组合生成器给出了相关系数和条件相关系数的计算公式,该公式易于实现快速计算.基于此公式计算了蓝牙组合生成器的各种相关系数,并列出了部分结果.