基于RSA的数字签名算法及其快速实现

在基于RSA的数字签名算法中,直接决定实现效率的是大数模幂运算。对基于二进制的Montgomery算法进行了改进,并将其应用于大数的模幂运算中。改进后的算法在保证算法快速实现的同时,又节省了算法运算空间。     

基于RSA的数字签名算法及其快速实现

在基于RSA的数字签名算法中,直接决定实现效率的是大数模幂运算。对基于二进制的Montgomery算法进行了改进,并将其应用于大数的模幂运算中。改进后的算法在保证算法快速实现的同时,又节省了算法运算空间。     

一种RSA算法之数字签名系统的快速实现方案

不同于常规的二进制幂模算法,该文采用一种更快速有效的滑动窗口法来实现幂模运算,同时结合Montgomery算法和中国剩余定理相结合来实现RSA签名,并给出了签名和验证的流程图。实验结果表明,以1024bit签名为例,采用滑动窗口算法比采用二进制算法要快22．3％;而综合采用滑动窗口和montgomery算法结合中国剩余定理,一次1024bit签名仅需28ms。     

公钥加密算法RSA的一种快速实现方法

RSA算法是基于数论的公开密钥密码体制。RSA算法的实现难度大,运算时间长。而影响其运算速度的主要因素是大数模幂算法和私钥算法。本文提出了改进大数模幂算法和快速计算私钥算法,并加以实现,该算法可以提高RSA算法的运算速度。     

一种有效的Batch RSA改进算法

Batch RSA算法的解密性能与指数计算阶段的大数模幂运算的实现效率有着直接的关系.针对提升Batch RSA算法的解密性能,提出一种Batch RSA算法的改进方案.提升通过将Batch RSA算法指数计算阶段的一些运算量转移到加密方,并且运用多素数技术使得解密时大数模幂运算的模数位数和指数位数减小.理论分析和实验结果表明该方案不仅提升了批处理RSA算法的解密性能,且该方案易于并行实现,可使得基于多核平台的RSA密码算法的性能得到进一步提升.     

大数模幂乘动态匹配快速算法及其应用

针对 RSA、Elgamal、DSA等算法在进行数据加密或数字签名时都要进行复杂的大数模幂乘运算 ,本文分析了目前常用的几种大数模幂乘算法 ,并在此基础上提出了一种动态匹配快速算法 .实验表明 ,将该算法用于实现 RSA算法 ,其实现速度较其他算法有明显提高 .     

模幂与点乘m_ary算法中窗口大小的最优化估计

提出一种新大数模幂与点乘m_ary算法中窗口大小的最优化估计方法.该方法不同于传统的暴力搜寻方法,也不同于在窗口的取值范围内通过逐一测试程序来获得最优窗口大小的方法.其基于以下理论分析:模幂 m_ary算法的基本运算为大数乘法,其中包括大数平方算法和一般大数乘法;椭圆曲线加密算法中点乘的m_ary算法步骤与模幂的m_ary算法相同,后者的基本运算为倍乘和加法.根据m_ary算法的基本运算的调用次数,推算出了最优窗口大小的估计公式.通过实验对m_ary算法进行实现,并测试分析了根据估计公式计算出窗口大小的算法实现时间效率与理论分析基本吻合.     

基于CRT的低成本RSA芯片设计

提出了一种基于改进的Montgomery算法和中国剩余定理(CRT)的RSA签名芯片的VLSI实现.由于采用了新颖的调度算法,实现了用576b的模乘单元来完成1152b的RSA模幂运算,从而大大降低了芯片面积;此外,CRT的引入使得整个系统的数据吞吐率与传统的1024bRSA系统相当.实验结果显示:芯片完成一次1024b的模幂运算需要约1.2M个时钟周期,而芯片规模在54K个等效门以下;如果系统时钟频率选取40MHz,系统签名速率可以达到30Kbps.     

模幂与点乘m_ary算法中窗口大小的最优化估计*

提出一种新大数模幂与点乘m_ary算法中窗口大小的最优化估计方法。该方法不同于传统的暴力搜寻方法,也不同于在窗口的取值范围内通过逐一测试程序来获得最优窗口大小的方法。其基于以下理论分析：模幂 m_ary算法的基本运算为大数乘法,其中包括大数平方算法和一般大数乘法;椭圆曲线加密算法中点乘的m_ary算法步骤与模幂的m_ary算法相同,后者的基本运算为倍乘和加法。根据m_ary算法的基本运算的调用次数,推算出了最优窗口大小的估计公式。通过实验对m_ary算法进行实现,并测试分析了根据估计公式计算出窗口大小的算     

RSA算法的一种高效软件实现方法

分析了RSA算法的软件实现难点为大数的幂模运算,提出了将大数的幂模运算转换为小数幂模运算乘积的高效方法,并实现了RSA算法,该方法在理论分析和试验方面都具有较好的效果。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。