无对运算的无证书签名方案的攻击与改进

无证书密码体制解决了基于身份公钥密码体制中的密钥托管问题和基于传统公钥证书密码体制中的证书管理问题,基于此无证书密码体制已成为密码学研究的热点之一.最近,樊爱苑等人提出了一个无双线性对运算的无证书签名方案,通过对其进行安全性分析,发现该方案不能抵抗A-I类伪造攻击,并给出了一种具体的攻击方法.针对该方案的安全缺陷,提出了改进方案,并对改进方案进行了正确性、安全性以及效率分析,分析结论表明改进方案在保持原方案高效性的同时,能抵抗A-I类和A-II类伪造攻击,提高了安全性.     

一种改进的针对滑动窗口模幂运算实现的密码数据Cache计时攻击

RSA,DSA等公钥密码大都基于“滑动窗口”算法实现模幂运算,其运算过程中进行的Cache访问会产生旁 路信息泄漏并用于密钥破解,基于Cache访问泄漏的幂指数分析算法是提高攻击效率的关键。通过分析现有攻击的 不足,进一步分析了预计算乘法因子到Cache的映射规律,提出了一种基于窗口值判定的幂指数分析改进算法;以基 本模幂运算为例,通过实际攻击实验验证改进算法的效率,结果表明改进算法可恢复出60%的幂指数位,优于前人最 好工作的4700;最后以RSA和DSA为例,给出了改进算法对密钥分析的影响。     

大整数模幂的固定基窗口组合算法

模幂乘运算是实现公钥密码体制的一个很重要的运算,其运算速度从整体上决定了公钥密码体制的实现效率。通过采用预处理技术,将椭圆曲线的定点标量乘的固定基窗口方法应用在模幂运算中,与SMM算法进行组合得到一种新的求模幂乘算法——固定基窗口方法。对算法的原理与效率进行了分析,实验结果表明,算法的运算速度得到了有效提高。     

基于无证书公钥密码的终端安全移动支付协议

移动支付协议允许两方或多方通过公开网络安全交换电子现金和数字内容.在实现安全支付过程中,传统公钥密码学的证书管理问题和基于身份密码学的私钥托管问题均给支付协议带来弊端.因此,使用无证书密码学来解决此类问题.针对高效的移动支付协议的设计问题展开研究,提出了一个基于无对的无证书密码学的移动支付协议.协议引入了口令等信息实现终端安全,还应用了密钥协商协议生成对称加密密钥,并且该过程伴随着支付过程,以此降低协议的计算和通信代价.此外,协议还可以实现公平交换等支付安全属性.     

可证安全的无对运算的无证书签密方案

无证书签密体制继承了基于身份签密体制无须使用公钥证书的特点,又对其密钥托管问题进行了改进,具有一定优越性。针对已有的无证书签密方案计算效率低、安全性差等缺点,基于一种安全的签名方案,提出一类新的无对运算的无证书签密方案。采用将哈希函数与用户身份绑定以及公钥与私钥相结合生成新密钥的方法进行构造。在随机预言模型下基于计算椭圆曲线上的离散对数困难问题证明了方案的机密性和不可伪造性。并与已往方案进行对比,在保证安全性的同时,该方案不使用双线性对和指数运算,效率较高。     

RSA公钥密码计时攻击研究及仿真

密码设备在执行加解密运算时泄露的时间信息能够被攻击者捕获,进而推算出密钥,破解密码系统。该文研究了RSA公钥密码算法和计时攻击的原理,分析了RSA加解密的模幂运算过程,阐述了基于模幂运算的RSA计时攻击原理,同时进行了仿真实现。仿真结果证明了RSA密码算法在计时攻击中存在安全缺陷,也说明了计时攻击与其他传统攻击相比更能准确快速地获得密钥。针对RSA公钥密码算法在计时攻击中存在的缺陷以及面临的安全威胁,讨论了抵御计时攻击的措施。     

一个高效的基于证书数字签名方案

基于证书公钥密码学是Gentry在Eurocrypt 2003上首次提出的,它克服了传统公钥系统中存在的证书管理问题和基于身份公钥系统中存在的密钥托管问题。基于计算性Diffie-Hellman假设,构造一个Shnorr型的高效的基于证书数字签名方案,并在随机预言机模型(Random Oracle Model)下证明其安全性。该方案在签名算法中不需要任何双线性对运算,在签名验证算法中只需要一个双线性对运算,在效率上优于已有的基于证书数字签名方案。     

改进的RSA算法在无线传感器网络中的应用

针对公钥密码体制在无线传感器网络密钥管理中存在计算速度慢、能量消耗大等问题,提出将一种改进的公钥算法应用其中。新算法利用蒙哥马利算法把大数的幂模运算转换成模幂运算,并使用中国剩余定理把模幂运算转换成求解同余方程组。算法安全性分析与实验结果表明,新算法能减少55%的运算开销,减少67%的存储空间占用,并增加21%的节点生命周期。新算法在保证密钥安全性的同时减少了运算量和存储空间,更加适合节点运算能力较低且能量有限的无线传感器网络。     

完美前向安全的基于身份认证密钥协商方案

现有的基于身份的一轮认证密钥协商方案没能实现强的完美前向性.采用强不可伪造的签名算法对临时公钥进行签名,提出一种改进的基于身份认证密钥协商方案.首先,对Boneh和Boyen提出的强不可伪造的短签名方案进行改造,提出一种强不可伪造的基于身份签名方案;然后,将新签名方案与Ni等人提出的eCK安全的基于身份一轮认证密钥协商方案相结合,提出新的密钥协商方案.进一步,为了实现新方案的可证明安全性,在对比分析eCK-PFS模型和eCK模型的基础上,融合现有安全模型,定义了基于身份认证密钥协商方案分析的强安全模型ID-eCK-PFS.在ID-eCK-PFS模型下,通过安全性规约,证明了新提出的基于身份认证密钥协商方案实现了强安全性,包括抗密钥泄露伪装、抗临时秘密泄露和完美前向安全性等.     

同余方程加密方案的研究

目前基于公钥的加密和会话密钥交换方案容易受到中间人攻击且效率不高。为此，提出了一种基于同余方程的加密和会话密钥交换方案，该算法可以安全高效地实现会话密钥的协商和加密消息的传输，并且还能防止中间人攻击。该方案在一定程度上防止第三者对传输消息的篡改，其安全性是建立在大数因子分解的困难性基础上的。     

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.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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