面向多网关的无线传感器网络多因素认证协议

无线传感器网络作为物联网的重要组成部分,广泛应用于环境监测、医疗健康、智能家居等领域.身份认证为用户安全地访问传感器节点中的实时数据提供了基本安全保障,是保障无线传感器网络安全的第一道防线;前向安全性属于系统安全的最后一道防线,能够极大程度地降低系统被攻破后的损失,因此一直被学术及工业界视为重要的安全属性.设计面向多网关的可实现前向安全性的无线传感器网络多因素身份认证协议是近年来安全协议领域的研究热点.由于多网关无线传感器网络身份认证协议往往应用于高安全需求场景,一方面需要面临强大的攻击者,另一方面传感器节点的计算和存储资源却十分有限,这给如何设计一个安全的多网关无线传感器网络身份认证协议带来了挑战.近年来,大量的多网关身份认证协议被提出,但大部分都随后被指出存在各种安全问题.2018年,Ali等人提出了一个适用于农业监测的多因素认证协议,该协议通过一个可信的中心(基站)来实现用户与外部的传感器节点的认证;Srinivas等人提出了一个通用的面向多网关的多因素身份认证协议,该协议不需要一个可信的中心,而是通过在网关之间存储共享秘密参数来完成用户与外部传感器节点的认证.这两个协议是多网关无线传感器网络身份认证协议的典型代表,分别代表了两类实现不同网关间认证的方式:1)基于可信基站,2)基于共享秘密参数.分析指出这两个协议对离线字典猜测攻击、内部攻击是脆弱的,且无法实现匿名性和前向安全性.鉴于此,本文提出一个安全增强的可实现前向安全性的面向多网关的无线传感器网络多因素认证协议.该协议采用Srinivas等协议的认证方式,即通过网关之间的共享秘密参数完成用户与外部传感器节点的认证,包含两种典型的认证场景.对新协议进行了BAN逻辑分析及启发式分析,分析结果表明该协议实现了双向认证,且能够安全地协商会话密钥以及抵抗各类已知的攻击.与相关协议的对比结果显示,新协议在提高安全性的同时,保持了较高的效率,适于资源受限的无线传感器网络环境.     

WSN中基于ECC的轻量级认证密钥协商协议

为解决无线传感器网络密钥管理与认证协议设计中由于节点频繁移动所带来的计算量、存储量等资源消耗过大问题,提出了一种基于ECC的轻量级认证密钥协商协议。该协议主要用于网络中任意用户节点之间,以及用户节点与网络之间的双向认证和会话密钥的协商。方案采用ECC进行会话密钥协商,结合AES对称密钥加密技术保证信息传输过程的保密性。与传统的密钥协商协议相比,能够在更小的密钥量下提供更大的安全性,并减少了对节点计算量和存储量的需求。该协议在ID-BJM安全模型下证明了其安全性。分析结果表明,该协议满足前后向安全性和PKG前向安全性。     

WSN中的无证书认证和密钥协商协议

由于无线传感器网络节点在能量、计算能力和存储能力等方面的局限性,传统的网络认证密钥协商协议难以直接应用到无线传感器网络中。为此,基于无证书的公钥密码体制,提出一种适用于无线传感器网络的认证和密钥协商协议,克服传统公钥认证的证书管理问题和基于身份认证的密钥托管问题。通过分析证明该协议满足认证协议各方面的安全属性要求,与已有的认证密钥协商协议相比,系统开销更少。     

无线传感器网络节点间认证及密钥协商协议

无线传感器网络的特性使它面临着比传统无线网络更大的安全挑战,其安全解决方案必须兼顾安全性和系统性能等因素。节点间认证及密钥协商是构建安全网络最基本的协议,是密钥管理协议和安全路由协议等的实现基础。很明显,包括传统Adhoc在内的各种无线网络领域中的安全认证及密钥协商机制都无法适用于无线传感器网络。为此,在充分考虑无线网络攻击方法和无线传感器网络自身特点的基础上,结合基于ID的公钥密码技术,提出了椭圆曲线双线性对上的无线传感器网络节点安全认证及密钥协商协议。分析发现,该协议不仅满足安全性要求,同时,能够适合无线传感器网络的特殊应用要求。     

新的适用于WSN网络的双方认证密钥协商协议

在无线传感器网络（Wireless Sensor Network,WSN）中,如何消耗较小的计算量建立传感器之间的身份认证和会话密钥一直是学界研究的热点。基于椭圆曲线密码体制设计了一种新的认证密钥协商协议。之后对新协议进行了安全性分析和性能分析。分析结果表明,新方案在确保自身安全的前提下,以较小的计算代价实现了WSN网络节点之间的安全密钥协商目标。     

一种车载mesh网络漫游匿名接入认证协议

无线mesh网络的特性使它面临着比传统无线网络更大的安全挑战。其安全解决方案必须兼顾安全性和应用环境等因素。用户节点的接入认证与密钥协商是节点漫游时最基本的安全协议,是安全路由等协议的实现基础。在多跳车载mesh网络用户节点接入认证中,用户身份信息的保护非常重要,然而有关车载mesh网络用户节点漫游时的匿名认证的研究较少,为此,在充分考虑无线mesh网络自身特点的基础上,结合基于Hash和Diffie-Hellman算法,提出一种高效的用户节点匿名接入认证与密钥协商协议。分析发现,该协议不仅可以满足安全性需求,在现实应用中也是可行的。     

基于TePA的无线传感器网络安全方案

针对无线传感器网络的安全需求, 结合TePA技术提出了一种基于TePA的无线传感器网络安全方案。该方案简化了TePA技术的身份认证分组和分组字段, 解决了无线传感器网络在传感器节点接入和密钥协商的问题。采用改进的BSW逻辑验证了协议, 并从协议安全性和网络性能方面分析了方案, 结果表明方案能抵抗中间人攻击和重放攻击, 并适合无线传感器网络。     

对两个无线传感器网络中匿名身份认证协议的安全性分析

针对设计安全高效的无线传感器网络环境下匿名认证协议的问题,基于广泛接受的攻击者能力假设,采用基于场景的攻击技术,对新近提出的两个无线传感器网络环境下的双因子匿名身份认证协议进行了安全性分析。指出刘聪等提出的协议(刘聪,高峰修,马传贵,等.无线传感器网络中具有匿名性的用户认证协议.计算机工程,2012,38(22):99-103)无法实现所声称的抗离线口令猜测攻击,且在协议可用性方面存在根本性设计缺陷;指出闫丽丽等提出的协议(闫丽丽,张仕斌,昌燕.一种传感器网络用户认证与密钥协商协议.小型微型计算机系统,2013,34(10):2342-2344)不能抵抗用户仿冒攻击和离线口令猜测攻击,且无法实现用户不可追踪性。结果表明,这两个匿名身份认证协议都存在严重安全缺陷,不适于在实际无线传感器网络环境中应用。     

面向天地一体化网络的认证与密钥协商协议

天地一体化网络具有通信模式复杂和动态性、开放性、资源受限等特点,本文针对现有认证与密钥协商协议需要多因子参与认证、计算与通信开销大等问题,分析天地一体化网络安全需求与性能需求,提出一种面向天地一体化网络的认证与密钥协商协议.为适应天地一体化网络的多层级架构,协议采用树状结构,共包括相邻节点认证与密钥协商和跨节点认证与密钥协商两个阶段.在相邻节点认证与密钥协商过程中完成各节点的组网认证,形成认证表格,为后续通信提供认证数据;采用透明传输的思想,基于切比雪夫混沌映射技术实现跨节点认证与密钥协商,保证会话密钥协商的安全性.针对节点高度动态变化的特点,设计认证预测机制,预测节点的运动轨迹,提前完成节点认证数据的迁移,实现不同通信模式无缝切换,提高通信效率.安全性分析和性能分析表明,与同类型的协议相比,本文协议在安全性上具有明显优势,并且降低了通信与计算开销,满足天地一体化网络的轻量级需求.     

一个新的基于身份的无线传感器网络密钥协商方案

无线信道具有开放性,节点间建立配对密钥是无线传感器网络安全通信的基础。在大部分基于身份加密(Identity-Based Encryption, IBE)的传感器网络密钥协商方案中,使用双线对运算建立配对密钥,能耗高且耗时长。基于BNN-IBS身份签名提出了一个新的无线传感器网络密钥协商方案,节点通过Diffie-Hellman协议建立配对密钥,所需的密钥参数通过广播获得。与基于IBE的传感器网络密钥协商方案(IBE-based Key Agreement Scheme, IBEKAS)进行量化比较,结果表明本方案不仅提供了与IBEKAS同层次的安全性与可扩展性,且在能耗与时耗方面具有较明显的优势。     

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).