基于Hash函数的轻量级RFID双向认证协议

通过对轻量级RFID系统中基于Hash函数认证协议安全性及计算成本等因素进行研究,分析了目前该类协议存在的安全缺陷和计算成本。通过对协议的改进,提出了一种轻量级RFID双向认证协议,在满足同等安全性能的条件下,减轻了标签的计算成本,提高了标签的计算性能,并通过BAN逻辑形式化证明了协议的安全认证过程。通过51单片机与天线模块仿制电子标签进行实验,从安全性、隐私性、协议性能等因素与其他基于Hash函数的协议比较。实验表明,本协议认证过程时间更短,并当数据库标签数量越多,改进协议的计算成本优越性较其他协议越突出,具有一定的实用价值。     

一种改进的RFID系统的双向安全认证协议

针对现有RFID认证协议存在的安全性问题,设计一种基于Hash函数的改进的RFID双向安全认证协议,并对该协议的安全性进行BAN逻辑分析和非形式化分析,然后对该协议的时间性能、空间性能进行计算.通过分析和计算表明,新设计协议能够在标签和读写器之间双向认证,有效解决现有协议的所有安全性问题.并且对标签造成的计算量、存储量不大,是一种综合性能较好的安全认证协议.     

基于Hash函数与状态锁定的RFID认证协议研究

针对射频识别(RFID)系统中存在的标签数据机密、安全等问题,研究Hash函数相关协议与对称密钥机制的优缺点,提出一种基于Hash函数与状态锁定的安全认证协议.该协议采用单向Hash函数与对称加密方法,结合后台数据库与标签状态的锁定设置,并在认证结束后及时更新ID和密钥值,有效处理RFID认证阶段的安全风险问题.通过安全性分析表明,该协议既保证了标签的匿名性、完整性、机密性,又抵御了攻击者假冒、重传、去同步攻击,能较好地完成RFID系统中阅读器与标签的相互认证.     

EPoWs云存储认证算法

采用副本消除技术的云存储系统在认证过程中面临Hash泄露的威胁;基于PoWs(prove of owner-ships)的云存储认证算法有效解决了Hash泄露的问题,但是无法对抗重放攻击和Hash树还原攻击.针对这些问题,在分析PoWs算法的基础上提出一种改进的PoWs认证方案,在不增加密钥协商机制的基础上对部分认证信息进行加密,使得中间人无法还原Hash树.同时在加密过程中引入时间戳机制,对抗重放攻击,降低了PoWs认证过程中云端的负载.     

通用可组合的自更新Hash链认证模型

利用通用可组合安全的框架定义了自更新Hash链认证理想函数,设计了基于一次签名理想函数的真实协议,并证明了在安全伪随机函数和单向无碰撞Hash函数的前提下,该协议能够实现所提理想函数。     

一种基于Hash的RFID双向认证的安全协议

对RFID技术所面临的安全问题进行分析,结合当前RFID认证协议的优缺点,提出了一种基于Hash函数的RFID双向认证的协议.协议采用随机数与动态ID结合的双向动态认证,通信认证过程加密.与同类型协议对比分析表明,该协议可以有效抵御非法读取、位置跟踪和重放等安全问题,同时能够满足标签低成本的需求,并且有着更优的执行性能.     

基于Hash函数的抵御失去同步RFID安全认证协议

针对无线射频识别(RFID)技术存在的同步安全隐患,提出一种新的基于单向Hash函数的安全认证协议,以解决存在于RFID系统中的各种安全问题,并对提出的协议进行基于GNY逻辑的形式化证明和对比分析.结果表明,该协议可有效解决窃听、重放攻击、失去同步等安全问题,在能耗、安全与性能方面优于当前其他主流协议.     

基于混沌理论的身份认证方案

基于混沌理论和一次性口令认证技术, 提出一种可以抵御常见攻击的身份认证方案. 解决了常规一次性口令认证方案不能抵御小数攻击、 明文传送迭代次数不安全以及传统Hash函数存在易于找到碰撞安全漏洞的问题, 该方案用混乱和散布性质好、 抗碰撞能力强的混沌Hash函数代替传统的Hash函数, 用混沌置乱排序算法产生的迭代次数代替网上明文传输的迭代次数, 具有较高的安全性.     

传感器网络中一种轻量级的安全重编程方法

针对无线传感器网络中无率码重编程协议现有安全方案开销过大的问题,提出一种分层Hash树(HHT)的认证方法,该方法由两层Merkle树组成,底层基于代码映像页构建多个小Hash树,并把这些树的树根聚合成根指纹以减小通信开销,然后以根指纹为叶子节点构造顶层Hash树以减小认证开销.对HHT方法的安全性进行证明,并应用该方法实现SReluge协议的页认证.实验结果表明:与Merkle树相比,HHT的认证开销有明显下降,同时降低了通信开销、构建开销和分发完成时间.     

射频识别LMAP协议改进研究

安全问题是射频识别技术领域的重要问题,轻量级安全协议成为该技术领域研究的主流.针对轻量级相互认证协议易受克隆攻击、去同步攻击等安全隐患问题,在对原有协议分析的基础上提出了系列改进措施,即通过对原有协议增加时间戳机制、物理不可克隆函数(physical unclonable function,PUF)电路以及改进密钥的生成方式来提高协议的安全性,并利用BAN逻辑对改进协议的安全性进行形式化证明.从安全性、计算量和存储量等方面将改进协议与其他协议进行比较,结果表明,协议安全性高,计算量小,也适合标签的存储量,在射频识别领域安全方面具有一定的应用价值.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.