基于时间核查和代码混乱的移动代理安全方案

移动代理是一种可以在计算机网络中进行自主异步传输的程序,具有很好的应用前景;但移动代理安全性问题的存在,严重阻碍了它在实际中的应用。保护代理免受恶意主机的攻击是移动代理系统独有的安全问题。由于代理必须在主机环境中运行,有效解决该问题比较困难。提出一种基于代码控制流混乱和时间核查技术的移动代理保护方案,该方案在实际网络管理系统中进行了验证,能够有效识别恶意主机,移动代理的保护率达95％以上。     

基于接入层的网络安全防御技术研究

针对病毒和恶意攻击导致网络中断甚至瘫痪的现象,通过对接入层交换机的恶意病毒攻击的安全防御过滤技术,使交换机智能识别网络中携带恶意病毒的主机,并自动中断网络连接,把对网络的攻击源主机终结在接入层,提高网络对病毒和恶意攻击的抵抗力,保证网络安全,在某高校的网络环境中测试,取得了显著效果．     

计算机网络安全维护探讨

网络安全是指保护网络系统中的软件、硬件及信息资源,使之免受偶然或恶意的破坏、篡改和泄露,保证网络系统的正常运行、网络服务不中断.为使其不致因偶然的或者恶意的攻击遭到破坏,必须加强网络安全保障     

一种保护代理的移动目标防御方法

DDo S攻击对关键基础设施和互联网服务构成重大威胁.在客户和应用服务器之间引入代理作为中间层的防御架构,恶意客户端能在发起DDo S攻击之前收集大量代理信息.为阻止系统受到来自内部人员发起的DDo S攻击、防止代理信息泄露,提出一种保护代理的移动目标防御架构PPMTD:提出代理隐藏算法,通过在身份验证服务器与应用服务器之间构造虚拟代理地址,实现对真实代理地址的隐藏;给出代理动态演化过程;将代理保护方案与代理地址转换算法结合,可有效减轻整个系统被攻击的概率、达到主动防御的目的.仿真实验验证了提出的隐藏算法可有效的降低代理被发现、系统被攻击的概率.     

基于电子货币技术的移动代理系统安全保护机制的研究

移动代理系统提供了一个新的计算方式,程序以软件代理的形式出现,它能在一台主机上停止它的执行,通过移动到另一台主机上恢复执行。随着移动软件混合性的增加,也伴随着对安全的威胁。尤其是对拒绝服务攻击这类消耗系统资源的攻击,目前还没有什么好的方法。提出了将电子货币引入系统来抵御这类攻击,并给出了一个应用模型。     

网络中移动代理安全保障机制的研究与实现

移动代理的安全性成为了移动代理系统在Internet及其它现代网络技术中推广应用的瓶颈。详细分析了移动代理系统中在数据传递和通信链接、服务器系统资源、移动代理运行环境以及移动代理自身安全等方面存在的种种安全威胁和隐患。然后分别对传输中的移动代理、服务器资源、执行环境中移动代理的保护方案进行了系统的研究,创造性地将JavaCard技术用于构建安全的移动代理执行环境。并在此研究成果基础之上设计并开发出SMMA2002移动代理安全模型系统。     

服务器的安全防护

服务器作为IT系统中的核心设备,因此,服务器的安全是每个用户都必须重视的问题.本文从服务器漏洞的修补、HIPS--主机入侵防护系统的应用、对"拒绝服务攻击"的防范、从系统内核入手的保护四个方面进行论述,旨在保护服务器,使其免受来自网络的威胁.     

保护移动Agent的电子交易安全方案

根据对移动Agent在恶意主机上安全问题的分析 ,给出了一个安全的电子交易方案 .该方案改进了强代理签名安全机制 ,使用不可拆分数字签名技术、公钥加密算法和时间戳 ,可以保证客户身份不可仿冒且要求不可拆分、商家身份不可仿冒且开价不可拆分、商家的身份和开价信息对其他商家保密 ,同时还可以抵抗客户或商家通过重放攻击来迫使对方进行额外的交易 .     

在使用代理时因浏览器缺陷引起的几种攻击的介绍

在不使用中间人攻击的情况下(伪造证书),HTTPS是比较安全的(sslv3防范了中间人攻击).但是,即使恶意代理无法直接读到HTTPS加密过后的明文,但是攻击者还是可以使用一些攻击的技巧来达到目的.这就是PBP-因浏览器的缺陷引起的代理攻击.本文说明了目前使用的代理机制上存在的威胁并阐述了这些威胁实现攻击的几种方法,并对于一些没有对浏览器及时更新或对没有好好管理所在局域网的代理的用户提出了警告,提醒在校学生在使用代理(所谓的加速器)上网时有可能存在的安全隐患.     

服务器的安全防护

随着计算机网络技术的发展,各个政府单位、学校、公司的计算机得到了互联,但同时增加了计算机的各种不安全因素。本文中所论述的服务器安全,是指如何保护服务器,主要从服务器漏洞的修补、HIPS-主机入侵防护系统的应用、对“拒绝服务攻击”的防范、从系统内核入手的保护四个方面进行论述,旨在保护服务器,使其免受来自计算机网络的威胁。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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