高效的基于口令多服务器认证方案

随着计算机网络的快速发展,传统的单服务器认证方案存在明显的不足。如果一个远程用户想要从不同的服务器获得网络服务,则必须分别向这些服务器提交注册信息。为解决这个问题,研究者提出了多服务器认证方案。然而,大部分多服务器认证方案不能抵抗某些密码攻击或者计算复杂度太高。本文提出一种高效、安全的多服务器认证与密钥协商协议。由于智能卡和读卡器使得实现这类方案的成本较高,新方案没有使用智能卡。与相关的多服务器认证方案相比,新方案同时具有高效性和安全性,因而更适合在实际环境中应用。     

基于二次剩余的多服务器环境下的身份认证协议

多服务器环境下的身份认证协议实现了用户只需要一次注册即可跟多个服务器实现交互认证,基于二次剩余构造了一个注册中心在线的多服务器环境下身份认证协议。该协议中,注册中心参与实现对用户的认证并协助用户和服务器建立后继通信的会话密钥,并且服务器之间是可以相互区分的。协议能够抵抗字典攻击、口令泄露模仿攻击常见攻击,同时能够实现相互认证,以及前向安全、已知会话密钥安全和无密钥控制等会话密钥的安全属性。     

多服务器环境下可实现访问控制的身份认证方案

相比单服务,多服务器环境的认证方案具有不需要用户重复注册和记忆多个密码等优点,近年来受到学界关注。2015年,屈娟等人提出一个多服务器环境下基于切比雪夫多项式的三因素身份认证方案。相比目前其他多服务器环境的身份认证方案,该方案具有一定新意。但通过分析可以发现该方案仍然存在如下缺陷：容易受到重复注册攻击;生物特征处理不恰当;认证过程严重依赖注册中心,容易遭受拒绝服务器攻击以及系统整体健壮性不高;协议部分设计存在不合理之处。为了解决上述问题,提出基于安全概略和切比雪夫多项式的三因素身份认证方案。通过分析可知该方案虽然计算量有所提升但是能较好解决屈娟等人所提方案存在的安全威胁,同时该方案也能实现访问控制。     

基于双线性映射的三因子远程身份认证协议研究

为了提高多服务器环境身份认证的安全性,降低计算复杂度,提出一种基于双线性映射的三因子认证协议,这些因子包括生物信息、智能卡和双线性映射密码。该协议包括系统设置、服务器注册、用户注册、登录、认证和密钥协商,以及密码更新六个阶段,其中,生物因子和智能卡作为核心因子涉及注册、登录、认证和更改阶段。Oracle形式化证明验证了该协议的安全性,攻击者无法得到标志、密码、生物特征信息等,可以实现密钥协商和双向身份认证。与其他相关协议相比,该协议在安全特征、智能卡存储成本、通信成本等方面具有一定优势。     

移动边缘计算环境下多服务器身份认证技术研究

移动边缘计算环境下多服务器认证(MSA)允许用户在注册中心的单个注册中获取多种服务器的多个服务,以前的单服务器认证需要用户注册所有的服务器才能使用各自功能.由于注册中心需要在每个认证环节都参与认证,因此造成了不必要的通信开销.针对移动边缘计算环境下移动边缘设备的低存储和低计算能力,提出一种基于切比雪夫混沌映射技术的单次...     

基于RSA的多Web系统智能认证代理模型

随着Web服务的不断深入研究,针对基于多Web服务器环境下的统一认证方法的研究日益重要。论文根据不同Web服务器的认证方式的特点,提出了多Web站点的智能认证代理模型实现统一认证。该模型利用Cookies、监听网络信息、RSA对称密钥体制等关键技术实现单个Web服务器的认证,并采用映射机制建立多Web服务器间的协作。该模型在某高校校园网内得以应用,用户只需登录一次即可完成一个复杂业务,对用户实现了透明认证。     

多服务器间基于动态身份的身份认证和密钥共识方案

多数的身份认证方案是依赖于单个的认证服务器与用户之间的相互认证,如果一个用户想要使用不同的网络服务,就必须向每一个服务器进行注册。然而要使得用户记住不同的身份和口令是非常困难的。最近,Li et al.分析了Sood et al.提出的多服务器间基于动态身份的认证方案,指出了其中存在的问题并且提出了一个改进的方案。Li et al.声称他们的方案可以保证用户的匿名性,提供了相互认证和共享密钥,并且可以抵抗一些常见的攻击。然而,通过仔细分析之后,我们发现Li et al.的方案容易受到假冒攻击。因此,本文提出了一种高效安全的多服务器间基于动态身份的相互认证和密钥共识方案并给出了安全性分析。     

基于混沌映射的用户匿名三方口令认证密钥协商协议

在基于混沌的三方口令认证密钥协商协议中,用户通过低熵的口令实现相互认证和共享会话密钥,以避免在身份认证过程中公钥基础设施或存储用户长期密钥的安全威胁。通过分析Lee提出的基于混沌映射的口令认证密钥协商协议,发现其协议不能进行口令变更,而且仅适用于用户和服务器之间的两方通信。为了改进此方案,提出两个基于切比雪夫混沌映射的用户匿名三方口令认证密钥协商协议,包括基于时钟同步的密钥协商方案和基于随机数的密钥协商方案。其中基于时钟同步的用户匿名三方口令认证密钥协商协议通信量少,基于随机数的用户匿名三方口令认证密钥协商协议更容易实现。两个方案的优点是用户仅选择一个简单的口令进行相互认证和密钥协商,服务器不需要再保护用户口令表,避免了口令相关的攻击,而且在相互认证过程中用户使用临时身份和哈希函数,实现用户匿名性,在增强协议安全性的同时,减少了通信过程中消息的数量,提高了协议的执行效率,具有完美前向安全,并用BAN逻辑证明了其安全性。     

基于扩展混沌映射的远程医疗信息系统认证方案

针对远程医疗信息系统（TMIS）的实时应用场景,提出了一种安全高效的基于扩展混沌映射的切比雪夫多服务器认证协议。该方案使用随机数和注册中心的私钥为用户/应用服务器的身份加密,有效地支持用户和应用服务器的撤销和重新注册。同时,还利用“模糊验证因子”技术避免离线密码猜测攻击,利用“honeywords”技术有效避免在线密码猜测攻击。该方案在公共信道上传输的与用户身份相关的信息均使用随机数或随机数的计算结果进行加密,因此可以为用户提供强匿名性。通过BAN逻辑证明该协议可以实现用户和服务器的安全相互认证;同时,使用非正式安全证明该协议可以抵抗多种已知攻击。     

在多服务器环境下的双因素动态身份鉴别方案

针对Li等人基于智能卡的多服务器身份认证方案,分析指出了其中存在的安全性问题,提出了一个改进的双因素动态身份鉴别方案.该方案为用户提供了一种关于身份注册信息的自我更新机制,用户可以在不与远程服务器通信的状态下,动态更新身份标志、口令和秘密参数等相关信息.另外,自验证的时间戳技术的借鉴利用,不仅避免了时钟同步问题,而且节约了产生随机数的开销.该方案还实现了用户的动态登录和对用户登录操作的可追踪性.新方案不仅继承了Li方案计算量低、存储量小的优点,而且还提高了认证方案的安全性和实用性,可以适用于实际的网络环境和应用.     

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     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

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。