一种基于摘要口令加密私钥的数字签名模式

PKI基础设施采用证书管理公钥,通过第三方的可信任机构-认证中心CA,把用户的公钥和用户的其他标识信息捆绑在一起,在Internet网上实现漫游证书的应用。用户的私钥存储存在一些安全性问题,私钥一旦泄露,或被破坏,就无法安全地实现信息的加密和数字签名。通过摘要口令将私钥加密存储在远程服务器,即可保证私钥的安全性。     

高效的基于身份的认证密钥协商协议

王圣宝等(王圣宝,曹珍富,董晓蕾.标准模型下可证安全的身份基认证密钥协商协议.计算机学报,2007,30(10):1842-1854)提出的标准模型下可证明安全的基于身份的认证密钥协商协议不具有私钥产生中心(PKG)前向安全性。针对该安全缺陷,提出了一种新的基于身份的认证密钥协商协议,协议中给出了一种利用用户私钥和临时秘密信息联合计算共享秘密的方法,并在标准模型下证明了协议的安全性。与已有协议相比,新协议具有较高的执行效率。同时提出了一种PKG与用户共同协商私钥的方法,即用户的私钥由用户产生的部分秘密信息以及PKG的系统主密钥共同生成,从而有效解决了基于身份的认证密钥协商协议的PKG前向安全性问题。     

基于指纹加密保护的USB Key安全方案

USB Key目前在网络身份认证中应用十分广泛,它采用PIN码来保护内部的证书和私钥,然而PIN码容易遗忘,也容易被窃取,是USB Key安全系统中最薄弱的环节;本文通过指纹加密技术,用指纹来控制用户对USB Key的访问,用户访问USB Key时不再需要记忆PIN码,提高了易用性;同时也可以抵御口令猜测攻击,提高了USB KEY的安全性.     

可信移动平台身份管理框架*

针对网络用户身份管理难题及现有的身份管理方案存在的不足,基于可信移动平台完整性校验、保护存储、域隔离和访问控制以及远程平台校验等安全特性,提出了可信移动平台身份管理方案和协议;构建了对应于口令、证书、指纹等认证方式的身份矩阵;实现了多种方式的身份认证、身份认证审计记录,主密钥、审计密钥、平台AIK私钥的加密存储,以及移动平台的可信验证、加密身份的还原和服务提供者身份标志的查找定位,并实现了身份信息和认证数据的加密传输;进行了安全性分析,结果表明该方案在保护用户身份信息安全的前提下,大大减轻了用户身份管理的     

基于秘密共享的多因素区块链私钥保护方案

针对区块链缺少恢复机制导致用户私钥一旦丢失就难以找回的问题，提出了一种基于口令、秘密问题和指纹的多因素区块链私钥保护方案。该方案无需用户存储额外信息且可以完全在线上实施，并采用了抗遗忘的因素访问策略。在注册阶段，用户需要提供所有因素信息(包括口令、秘密问题和指纹)以及区块链私钥，并使用秘密共享方案为一组服务器分配秘密份额。在恢复阶段，用户仅需要提供部分因素并向多个服务器发送恢复申请，即可获得其秘密份额的信息并以此重构出区块链私钥。实验结果和启发式安全分析表明，该方案中客户端和服务端的计算开销都在毫秒级，可以抵抗已知攻击且通过支持多因素提供了更好的安全性。     

异构网络光传感通信跨域口令认证方式优化

为了解决异构网络通信跨域口令认证效率低、安全性差的问题,提出了改进传统C2C-PAKE认证协议安全性能,改善切换切入阶段时延的跨域口令认证方式优化方法.改近传统C2C-PAKE认证协议,建立分立式子层,形成多层扩展子层认证系统,引入私钥机制及随机序列数解密用户信息,生成跨域通信用户特有的认证口令,用自身私钥加密语义信息和认证协议,重复用户验证步骤,排除其它恶意攻击者,提高认证安全指数;在预切换和接人认证传输安全口令阶段,应用增加算法得到口令认证域间信任列表,提高认证效率,建立异构网络跨域通信实验环境,仿真对比结果表明,在安全性能和认证效率两方面,所提方法遭遇的认证威胁与认证开销均优于其它方法,具有广阔的应用空间.     

基于PPTP协议和混沌理论认证的VPN的实现

PPTP协议可以较好地保证VPN中的数据在传输过程中的安全性,但是传统的静态密码在身份认证时依然存在不少安全隐患.针时VPN的安全需求,提出了基于混沌理论的一次一密动态密码,构造了基于混沌理论的用户身份"指纹"的认证算法以及身份认证双方的混沌同步算法,把演化、发展的混沌序列作为用户的身份"指纹",实现了身份"指纹"的无约定动态变化,增强了VPN的安全性.     

基于加同态公钥密码体制的匿名数字指纹方案

提出了一种基于加同态公钥密码算法的匿名数字指纹方案,并给出了具有匿名功能的公钥和私钥对的具体构造方法,从而使该匿名指纹方案在发现盗版的情况下,销售商不需要第三方的帮助就能鉴别出数字多媒体作品的非法分发者,解决版权纠纷时也不需要购买者参与并提供相关的秘密信息,从而达到实现两方审判的目的.分析结果表明,该方案具有用户匿名及不可关联、销售商的可保证安全性和用户的可保证安全性等特点.     

可证明安全的基于身份的认证密钥协商协议

提出了一种具有私钥产生中心(private key generator,PKG)前向安全性的基于身份的认证密钥协商协议,协议中给出了一种利用用户双方的长期私钥和临时私钥联合计算共享密钥的方法.在标准模型下证明了协议的安全性,并且分析得出,即使攻击者能够同时获得双方的临时私钥或同时获得双方的长期私钥,共享密钥仍然是安全的.性能分析表明,该协议较好地平衡了计算复杂度和安全性这两个协议评价指标.     

Secure-OSCAR中基于PKI的生物身份认证的设计

个体的生物特征的唯一性和“不可伪造性”使得它很适合于身份认证。生物信息本来是不保密的,所以不能象使用口令一样来使用它,否则将不能提高反而会降低系统的安全性。公钥机制(PKI)也被广泛应用于用户身份认证中,但它是基于私钥的安全性的,不可避免地存在冒用私钥的威胁。论文提出一个结合生物技术与PKI技术的认证方式的设计,具体描述了它在Secure-OSCAR中的实现。     

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。     

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.