产生安全椭圆曲线的一种有效方法

本文在寻找安全椭圆曲线的CM方法的基础上,实现了一种更具适用性的产生安全椭圆曲线的有效方法。通常,为了抵抗诸如MOV等算法可能的攻击,以域GF（q)上的椭圆曲线为基础的公钥密码系统,对该椭圆曲线必须要求满足以下条件：m阶曲线具有一个形式为2p 1的大素数因子,这是p是一个素数且q^2≠1modm。这个条件在不损害安全性的情况下对形式为2p 1的大素因子可以放宽到包括形式为2ip 1的素数（i是一个小整数）。因此,适用于公钥密码系统的安全椭圆曲线的数目显著增加。本文对这一方法进行了实现,它表明用该方法来产生适用于公钥密码系统的椭圆曲线比原来的方案快很多。     

基于椭圆曲线的数字签名的盲签名

椭圆曲线数字签名实际上是基于乘法群的离散对数的数字签名的椭圆曲线上的模拟,本文描述了由ANS（1999）颁布的椭贺曲线数字签名算法（ECDSA）标准,提出了三个新的基于椭圆曲线的数字签名方案和两个盲签名方案。     

一种基于构造椭圆曲线方程的数字签名方案

椭圆曲线密码体制是通用公钥密码体制签名中安全性很好的公钥密码体制。描述了非超奇异椭圆曲线方程的构造方法,提出了一种基于椭圆曲线构造方程的数字签名方案,并进行了安全性分析。     

基于椭圆曲线的代理数字签名

现有的代理数字签名方案都是基于离散对数问题和大数因子分解问题的方案.本文我们将代理签名的思想应用于椭圆曲线数字签名,提出了一种新的基于椭圆曲线离散对数问题的代理签名方案,并对方案的复杂性和安全性进行了分析.在对方案的安全性分析中,我们还提出了两类椭圆曲线上的困难问题.新方案不仅推广和丰富了代理签名的研究成果,而且也扩展了椭圆曲线密码的密码功能,为信息安全问题的解决提供了新的密码学方法.     

A Secure Digital Signature Algorithm Based on Elliptic Curve and Chaotic Mappings

A digital signature algorithm (DSA) based on elliptic curve and chaotic mappings is proposed to strengthen the security of an elliptic curve digital signature algorithm (ECDSA). To construct this algorithm, a one-way hash function (OWHF) based on two-dimensional (2D) hyperchaotic mappings and an improved elliptic curve public-key cryptography (IECPKC) are proposed, and two key exchange algorithms are introduced. Security analysis shows that this has better capability of resisting per-message secrets attack, repeated use of per-message secrets attack, and duplicate-signature key selection attack than an ECDSA. The proposed scheme is well suited for practical implementation.     

基于椭圆曲线的XML数字签名研究与实现

在分析基于椭圆曲线的XML数字签名流程及其安全性的基础上，改进影响椭圆曲线签名算法（ECDSA）实现效率的关键模块，提高其整体运算效率，实现了基于椭圆曲线的XML签名服务。在统一平台上对三种公钥密码服务实现XML数字签名的性能进行比较，实验结果表明，在XML签名中使用ECDSA，能够实现网络环境中高安全性、高效率的数字签名处理。     

基于椭圆曲线的盲签名与离线电子现金协议

将基于乘法群的离散对数的数字签名映射到椭圆曲线上，提出了一个基于椭圆曲线的盲签名方案，并在其基础上利用Brands的受限盲签名技术构建了一个高效的离线电子现金协议。     

一种有效的椭圆曲线代理签名方案

现有的代理数字签名方案大多是基于离散对数问题和大数因子分解问题的方案.本文将代理签名的思想用于椭圆曲线数字签名,提出了基于椭圆曲线的代理签名方案,除了满足代理签名的七条基本性质外,还对目前已有的代理签名方案中尚未很好解决的问题--代理权的滥用进行了有效的控制.在本方案中,签名人不能生成代理签名,也不能给多于一个的人以代理权,真正做到了对签名代理权的控制.本方案基于椭圆曲线,且整个过程参与方少,具有安全性高、密钥量小、便于实现等优点.     

The Half-Wave Stepped Digital Elliptic Filter

A design procedure for narrow-band bandpass TEM-line elliptic-function filters is presented. The proposed realization is in the form of a stepped-impedance digital n-wire line which is one-half of a wavelength long at midband and short circuited to ground at both ends, where the digital line is stepped in impedance along any arbitrary prescribed plane in the filter. Due to its physical form and mode of electrical operation, the filter has been termed the half-wave stepped digital elliptic filter. A detailed design procedure for the construction of the two characteristic admittance matrices which describe the digital n-wire line from the low-pass prototype element values is presented. It is also shown that the normalized impedance values of the elements in the filter are all of the order of unity and independent of the actual bandwidth of the falter except for the input and output transformer elements. A numerical example and experimental results on a seventh-degree 1-percent bandwidth filter with a center frequency at 3.7 GHz are given, demonstrating the significant improvements which may be obtained from the half-wave stepped digital elliptic filter over most other known form of microwave TEM-line narrow-band bandpass filter.     

基于DDS的低通滤波器的设计与实现

基于DOS技术的基本原理,以设计低通滤波器为目的,采用EDA软件Multisim2001进行仿真,研究了低通滤波器的设计方法,确定了低通滤波器的结构、阶数,并设计相关参数,得出了截至频率为120MHz的7阶的低通滤波器,其幅频特性好,具有快速的衰减性。     

Current-mode elliptic filter design based on symmetrical current switching

This paper describes a current-mode elliptic filter structure based on dual-output OTAs and grounded capacitors. The filter is capable of producing both lowpass and highpass notch responses without changing the filter structure. This is achieved using a symmetrical current switching technique based on two switches controlled with a 2-bit digital word. The proposed filter structure forms a basic second-order building block in the design of high-order elliptic filters with tuneable frequency response. To confirm the theoretical analysis, simulated and measured results of fourth-order elliptic lowpass and highpass filters with tuneable bandwidth in the range of 0.65MHz to 1.3MHz are included. Finally, detailed analysis of the OTAs non-ideal parameters on the filter performance is presented and an example is given.     

倾斜放置二维数字阵列雷达天线参数优化

介绍了二维相控阵或二维数字阵列天线锥形扫描与俯仰、方位扫描时的坐标变换,重点阐述了倾斜放置二维相控阵或二维数字阵列天线按俯仰、方位扫描时的坐标变换关系,基于该坐标变换,得出倾斜放置二维平面相控阵或二维平面数字阵列天线扫描区域边界在变换域上呈椭圆形的结论。基于这样的结论,可以实现对阵面倾斜角度、几何参数的优化。     

Design of multiplierless elliptic IIR filters with a smallquantization error

We present a new technique for the design of multiplierless IIR elliptic filters. The multiplierless filter has all multiplication constants implemented with a small number of shifters and adders. The proposed technique is based on sensitivity analysis. An analytical expression for amplitude response sensitivity is derived for the filter structures consisting of two allpass subfilters in parallel. It is shown that the amplitude response sensitivity to some constant x can be expressed as a product of the filter reflectance function and the phase sensitivity of the allpass section that implements the constant. The closed-form expressions for the phase sensitivities of the first- and second-order allpass sections are also developed. It is shown in the paper that the (n+1)/2 most sensitive constants can be directly controlled by the transfer function parameters if the transfer function is derived by the bilinear transformation from an elliptic minimal Q-factors (EMQF) analog prototype. This way, (n+1)/2 multiplication constants can be implemented without quantization, leaving the filter characteristic strictly elliptic. This is achieved for a class of low-noise allpass sections and for the wave lattice digital filter as well. The quantization of the remaining (n-1)/2 less-sensitive constants is performed using the phase-tolerance scheme and phase-sensitivity functions. The proposed design technique is straight-forward and, consequently, very fast. The application is demonstrated on the examples of narrowband, wideband, and halfband filters     

The Digital Elliptic Filter--A Compact Sharp-Cutoff Design for Wide Bandstop or Bandpass Requirements

Detailed design procedures are presented for a practical elliptic-function filter form capable of achieving high selectivity in a very compact configuration. This filter form, called the digital elliptic because of its digital construction and elliptic function response, can provide either bandpass or bandstop characteristics. Examples are given to illustrate typical design procedures for both bandpass and bandstop applications. Experimental results are presented for an octave bandstop design.     

基于椭圆曲线密码数字签名的研究与实现

设计了一个基于椭圆曲线密码体制的数字签名方案,实现了该数字签名系统.     

一种基于椭圆曲线的前向安全数字签名方案的分析与改进

针对已提出的一种基于椭圆曲线的前向安全数字签名方案进行安全性分析,发现该方案存在安全隐患,不具备前向安全性.利用椭圆曲线上Weil配对的双线性性质对原方案进行改进,构造了一种新的基于椭圆曲线的前向安全数字签名方案,方案的安全性建立在目前还没有有效攻击方法的有限域上的非超奇异椭圆曲线离散对数问题之上.新方案具有前向安全性、抗伪造性等性质,有一定的理论和实用价值.     

Generators by the quadratic exponential method

Based on the quadratic exponential method, this paper constructs two types of generators over finite field Fq, the digital quadratic exponential generator and quadratic exponential pseudorandom vector generator. We investigate the distribution of the sequence generated by the generators, and present results about their one dimensional discrepancy. The proofs are based on the estimate of certain character sum over Fq. Ift is the least period of the sequence and t≥q^1/2＋2c, then the bound of the discrepancy is O（t^-1/4q^1/8＋τ logq） for any ε 〉 0. It shows that the sequence is asymptotically uniformly distributed.     

基于椭圆曲线的若干密码方案

由椭圆曲线上的点构成的代数系统可以为密码学提供多种应用方案。本文描述了基于椭圆曲线的数据加密体制、密钥交换方案和数字签名方案。上述方案的安全性建立在离散对数问题上,目前已知的攻击椭圆曲线对数问题的算法仍然是指数时间。本文还分析了安全椭圆曲线应满足的条件,给出了安全椭圆曲线密码系统的构造方法。     

数字签名算法及其比较

随着信息技术的发展,数字签名是电子商务、电子政务等应用的关键技术之一。文章介绍了数字签名的功能和基本原理,讨论了三类数字签名算法,并对比分析了它们在安全性能、计算速度、空间占用和通信带宽等方面的优劣。由于椭圆曲线数字签名各方面的优势,因而其具有很好的应用前景。     

Integrated high bandwidth wave elliptic lowpass switched-current filter in digital CMOS technology

The design and fabrication of a high bandwidth third-order analogue elliptic lowpass wave filter is described. The filter was realised using switched-current techniques and implemented on a standard digital 0.6 /spl mu/m CMOS process. The filter exhibits an elliptic response and achieves a bandwidth of 250 kHz, which is significantly higher than a previously reported fabricated switched-current wave filter.