基于IC协议的分块加密方案及其应用

快递面单泄密问题在给个人带来安全隐患的同时,也制约着快递企业的快速发展。针对快递面单隐私保护进行了研究。将基于身份的加密体制（BF-IBE）、权限设计思想及二维码技术相结合,设计了一种分块加密方案,采用一种新的用户私钥分发协议（IC协议）来解决密钥管理问题。将分块加密方案应用于快递隐私保护领域,设计了新型隐私面单与快递业务流程。结果分析表明,分块加密方案所采用的IC协议无须求逆运算,双线性对运算有效降低,便于密钥管理。在加解密效率上分块加密方案与BF-IBE相当,安全性基于椭圆曲线上的离散对数问题,应用于快递领域能有效保护用户隐私,可推广至其他有分块加密需求的领域。     

移动云计算中基于身份的轻量级加密方案

针对移动云计算中数据安全和移动用户的隐私保护问题,结合在线离线和外包解密技术,对基于身份加密机制（IBE）中加密和解密算法进行扩展,提出了一种可外包解密的基于身份在线离线加密方案,并证明其安全性,构造出适合于移动云计算环境中轻量级设备保护隐私数据的方案。为了减少移动终端运行IBE的加密和解密开销,利用在线离线技术将IBE的加密分解为离线和在线两个阶段,使得移动设备仅需执行少量简单计算即可生成密文;在此基础上,利用外包解密技术,修改IBE的密钥生成算法和解密算法,增加一个密文转化算法,将解密的大部分复杂计算外包给云服务器,移动设备仅计算一个幂乘运算即可获得明文。与现有IBE方案的性能相比,该方案具有较少的加解密开销,适合于轻量级移动设备。     

基于签名加密算法的短信息加密方案

结合椭圆曲线上的Tate配对和混合加密体制,提出了一种新的签名加密算法,它集密钥交换、数字签名和数据加、解密功能于一体;针对短信息系统自身的特点,基于该算法提出了一种适用于短信息系统的加密方案,能完全抵抗生日攻击,既安全又实用。     

TinyIBE：面向无线传感器网络的身份公钥加密系统

由于无线传感器网络节点的资源受限,大部分公钥加密算法被认为无法适用.最近的研究则显示椭圆曲线加密算法ECC(Elliptic Curve Cryptography)在无线传感器节点上运算可行,基于身份的公钥密码体制IBE也因此成为研究热点,但尚无出现完整的解决方案.在分析面向TinyOS的公钥算法相关研究工作基础上,设计实现了一套基于Tate对的身份公钥加密系统TinylBE.首先给出椭圆曲线选择及Tate对参数优化过程,再设计在线和离线PKG两种应用方案,最后在MICA2节点上给出测试结果.     

基于IBE的XML加密数据安全交换研究

当前XML加密普遍采用对称算法和非对称算法组合的二次加密方式,并且密钥交换依赖传统PKI体制,存在加/解密过程复杂等缺陷。通过对XML加密规范和IBE体制以及双线性映射算法的研究,提出采用IBE密钥机制和双线性映射算法实现XML加密的数据安全交换方案,对相应的XML数据交换过程和XML加密文件结构进行了设计,对该方式的XML加密关键环节实现方式做了具体阐述。作为一种新型XML加密方案,在保证数据安全交换的同时,简化了XML加密过程,并克服了传统PKI的缺陷。     

一种基于属性的固定密文长度广播加密方案*

针对目前基于属性的广播加密方案存在密文较长、加解密时计算花销较大等问题,提出了一种高效的密文策略的基于属性的广播加密方案。该方案基于椭圆曲线加密算法,采用动态门限访问结构,加密方可根据需要动态调整门限值。该方案仅当用户的身份信息包含在广播的授权用户集合中并且用户的属性包含在访问结构中时,解密方方可通过双线性配对运算进行密文解密。方案的密文长度及加解密双线性对运算次数固定,计算效率高并且通信开销小。仿真结果验证了方案的有效性。方案安全性是建立在q-BDHE假设之上,在标准模型下可证CPA安全。     

超椭圆曲线上的Ate对变种及其计算的研究

对超椭圆曲线上一类非退化的Ate对变种进行研究,使得计算双线性对的Miller算法的循环次数显著减少。通过对此类双线性对与改进Tate对及Ate对的关系的一系列证明,验证了此类双线性对的非退化性;基于广义的Ate对和Vercauteren在椭圆曲线上定义的Ate对,给出了两种超椭圆曲线上的此类双线性对的构造方法;针对此类变种的Miller函数,设计了计算此类变种的Miller算法并对其上的计算进行了详细的研究。     

基于计算机网络的椭圆曲线加密系统的硬件设计与实现

文章根据作者的实际开发过程,提出了一种切实可行的基于计算机网络的椭圆曲线加密系统。内容包括椭圆密码体制的选择、有效算法的设计和快速加、解密的硬件实现。并且详细阐述了利用多片数字信号处理器TMS320C50在微机上实现并行椭圆曲线加、解密系统的方法。     

基于FPGA椭圆曲线密码体制的研究

对基于FPGA椭圆曲线密码体制的实现进行全面研究,在Xilinx的FPGA上实现了二元有限域和椭圆曲线点运算的所有算法。将模乘算法、模逆算法、曲线点加算法、曲线点减算法、点乘算法、ECElgamal加密/解密方案、总线命令控制等在FPGA上完成仿真、综合和板级验证,并设计出具有PCI局部总线传输功能的加密/解密适配卡。研究中提出了新的基于正规基和正则基的比特串行模乘算法实现方案。     

基于FPGA椭圆曲线密码体制的研究

对基于FPGA椭圆曲线密码体制的实现进行全面研究,在Xilinx的FPGA上实现了二元有限域和椭圆曲线点运算的所有算法。将模乘算法、模逆算法、曲线点加算法、曲线点减算法、点乘算法、EC-Elgamal加密／解密方案、总线命令控制等在FPGA上完成仿真、综合和板级验证,并设计出具有PCI局部总线传输功能的加密／解密适配卡。研究中提出了新的基于正规基和正则基的比特串行模乘算法实现方案。     

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。     

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。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).