采矿CAD图元集的构造及多边形图元和标注图元的表述

本文对采矿CAD系统中基本图元集的构造及其表述方法进行了研究。提出了一个7元素采矿CAD基本图元集构造方案；讨论了曲线图元和尺寸标注图元的表述方法，提出用“多边形图元”代替“曲线图元”。该图元集构造方案对基于线框构图技的采矿CAD软件开发有一定的指导意义。     

Digital Document Signing: Vulnerabilities and Solutions

ABSTRACT

Digital signature is the key issue in a number of innovative processes, such as dematerialization, e-government, e-commerce, and e-banking. Digital signature ensures both the identity of the user and the integrity of the digital document the user signs. However, despite the robustness of the underlying cryptographic primitives, a number of vulnerabilities derive from the radical difference between handwritten signature on papers and signature on digital documents. Indeed, digital documents are not directly observable because humans need a tool to interpret the bits of the document and to represent the corresponding information. The aim of this paper is to focus on the vulnerabilities of digital signature deriving from the “unobservability” of electronic documents. Possible mechanisms to contrast such vulnerabilities are also proposed, highlighting their positive and negative points under a perspective that does not ignore both practical and regulatory aspects.     

Performance of the most common non‐cryptographic hash functions

Non‐cryptographic hash functions (NCHFs) have an immense number of applications, ranging from compilers and databases to videogames and computer networks. Some of the most important NCHF have been used by major corporations in commercial products. This practical success demonstrates the ability of hashing systems to provide extremely efficient searches over unsorted sets. However, very little research has been devoted to the experimental evaluation of these functions. Therefore, we evaluated the most widely used NCHF using four criteria as follows: collision resistance, distribution of outputs, avalanche effect, and speed. We identified their strengths and weaknesses and found significant flaws in some cases. We also discuss our conclusions regarding general hashing considerations such as selection of the compression map. Our results should assist practitioners and engineers in making more informed choices regarding which function to use for a particular problem. Copyright © 2013 John Wiley & Sons, Ltd.     

基于RFID技术的分布式密钥安全保护机制

文章主要基于RFID技术，实现分布式密钥安全保护机制。文章将密钥拆分成不同的子密钥存储到不同的标签上，通过扫描多个分布式便携电子标签，来获取密钥，在保证密钥安全的同时实现了个性化的终端解锁方式。由于标签具有便携性，所以终端用户可以将其随身携带。由于该机制不改变硬件结构和协议内容，实现方便，成本低廉，有十分光明的应用前景，未来可扩展到其他物联网应用场景下。     

基于分数阶Hilbert变换的多路加密

基于分数阶Hilbert变换的单边带通信可以同时将分数阶旋转角度作为加密密钥,从而保证通信安全。但基于分数阶Hilbert变换的单边带通信加密技术只能让信号使用一个加密密钥。为了达到增大密钥空间以更有效地保证信息安全的目的,采用多通道滤波器组分路处理的方法,在减少了系统计算复杂度的基础上增大了密钥空间。     

AHB总线在密码SoC中的设计与应用

为了提高密码SoC的接口的规范性能和系统的整体性能,提出了一个基于AMBA总线规范高性能总线AHB的多密码算法IP核的集成方案。首先对AHB高性能总线进行了FPGA实现,并在此基础上实现了多个密码算法IP核与AHB总线的挂接,完成了基于AHB总线的片上系统集成。最后对AHB总线和密码算法集成进行了仿真和FPGA测试,并验证了实现的正确性。     

针对RSA-CRT数字签名的光故障攻击研究

通过研究密码芯片SRAM存储单元构造,利用激光改变进行运算的SRAM存储单元的逻辑状态,分析光注入对SRAM存储单元的影响。以Montgomery乘的 RSA－CRT数字签名算法为攻击对象,分析其算法的实现过程和故障注入机理。针对密码芯片实现的8位RSA－CRT签名算法,使用半导体激光作为注入光源,搭建光注入实验平台,在计算Sq时刻进行故障注入,从而得到故障签名,通过分析故障签名与N的关系,成功的获得了大素数q,验证了光故障攻击的有效性。     

Meaning of words and the use of axiomatics in psychological theory.

Two problems are discussed: Can and should psychological concepts be defined, and can and should they be organized in an axiomatic system? I point out that definitions in terms of physiological or behavioral measures are strictly impossible because any particular measure can mean anything, whereas phenomenological definitions always point to antecedents and consequents. I then point out that definitions of antecedents and consequents can be given either in terms of causes or in terms of reasons, and that causes and reasons belong to two incompatible languages. Causes exist independently of persons and reasons exist only for persons. Only the latter belong to psychology, as I see it. The working of the system of psycho-logic is illustrated by an analysis of the conditions of trust. I conclude that psychological terms should be defined by means of semantic primitives, and that one should try to organize them in an axiomatic system. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

手写运动的协作基元合成分析方法

研究一种生物运动神经控制机理与数据合成分析相结合的手写运动分析方法.特别地,将运动协作基元的概念用于手写运动数据分析,研究手写运动的协作基元合成分析方法,建立符合生物运动神经控制规律的手写运动数据理解模式.提出的协作基元合成分析过程由2个交替迭代的优化算法组成:其一,基于非负矩阵因子分解模式估计协作基元及调制幅度;其二,采用相似性最大化准则估计协作基元的激活时间.针对笔画切分的实验研究表明,采用协作基元合成分析方法获得的笔画切分结果,能够很好揭示相邻笔画之间的重叠连接模式,证实了所提方法的有效性.     

基于分块字典的可视密码改进方法

针对目前可视密码术引起的像素膨张、与原密图相比,叠合图像的亮度、对比度降低问题,提出一种新的基于分块字典的可视密码改进方法。该方法首先根据确定大小的像素分块,列举每个子图各子块像素分布情况后建立相应的分块字典,并对分块字典条目进行编号;然后对原密图置乱后,将原密图分成两个子密图;再分别两个子密图进行均匀分割,将其分成若干子块,所有密图子块对应一个字典编号并进行一维化,则得出由两个子图所有子块编号组成的序列。由此,密图就由这个分块字典编号序列所确定,经过传输后,提取并组成字典编号序列,二维还原后与相应的分块字典条目对应,装配得出两个子图叠合后还原成原密图。与以前的可视密码算法,如（k,n）门限方案等相比,采用子图交错叠合、基于分块字典的可视密码改进方法,可减少算法复杂度,编码的比特序列长度是对原密图直接编码后的比特序列长度的两倍,从而减少像素膨胀,也不会引起叠合图像的亮度、对比度降低的问题。从而更具实用性。