两种基于身份的广播加密方案的安全性分析

针对孙瑾等提出的两种基于身份的广播加密方案进行了安全性分析,指出这两种方案存在安全缺陷.在第一种广播加密方案中,任何拥有合法私钥的用户都能冒充PKG给其他用户发布私钥.第二种广播加密方案的解密过程需要公开随机因子s,而s一旦公开,任何人都可以解密密文.因此,这两种广播加密方案都是不安全的.     

基于以太坊的格上属性基可搜索加密方案

提出了一种基于以太坊的安全、灵活、高效的格上属性基可搜索加密方案.方案基于格密码体制提出,解决了传统基于双线性配对技术的属性基可搜索加密方案存在的不可抗量子攻击安全问题.方案使用基于以太坊技术的分散存储方法解决了传统云存储系统中单点故障问题,并且方案中数据拥有者代替私钥生成器为用户生成私钥,这避免传统方案由于密钥托管问题造成的密钥滥用以及隐私泄露.采用以太坊的智能合约解决了以往属性基可搜索加密方案中云服务提供商不可信情况下关键字搜索结果的可靠性问题.与传统属性基可搜索加密方案相比,方案不仅可实现对加密关键字的细粒度检索,并且可抵抗量子攻击,增强了方案的安全性.在容错学习问题(learning with errors,LWE)假设下,证明了方案的安全性.     

格上抗合谋攻击安全的代理重加密方案

格上基于身份单向代理重加密方案并不能达到抗合谋攻击安全,通过简单的线性运算则完全可以恢复出被代理者私钥,针对这一问题提出了改进方案.通过密钥生成过程中添加适当的扰动,在确保正确解密的前提下,使代理者和代理合谋后获得的信息中含有丰富的噪声,从而隐藏了被代理者的真实私钥,达到了抗合谋攻击安全.在随机预言模型下,将新方案的安全性严格地规约为判定性带错误学习(LWE)困难假设,证明了其满足已知身份选择明文攻击下密文不可区分性(IND-PrID-CPA)安全.     

云环境下基于非线性映射的保序加密方案

针对传统保序加密方法安全性和效率不能兼顾的缺点,提出一种基于非线性映射的保序加密方案.该保序加密算法使用非线性映射和非线性分割的方法来隐藏数据分布和数据频率.介绍了云环境下保序加密的系统模型(含问题模型和敌手模型);对于问题模型提出了保序加密方案并且验证其正确性;进一步分析该方案在敌手模型2种攻击下的安全性,并与其他保序加密方案做对比.结果表明,所提出的保序加密方案可达到抗统计攻击和IND-DNCPA安全,有着良好的安全性;每十万个加密数平均加密执行时间大约30 ms,有着较高的效率;该方案可以用任何可编程语言部署和实现,有着良好的可编程性.     

基于门限的广播加密算法改进

为解决数字媒体上的版权问题.对广播加密方案以及能够有效剔除泄密者的泄密者追踪方案做出了深入的研究.采用基于身份的广播加密方案中加入基于门限的泄密者追踪机制的理论分析和实验方法,引入多个密码学哈希函数,并对私钥进行分组处理,实现了基于门限的广播加密及泄密者追踪方案算法的改进.研究结果表明:该算法降低了密文头的大小,压缩了公钥大小,减少了服务器开销,实现了优化叛徒追踪机制,能够推动广播加密技术在实际生活中的使用.     

一个新的带仲裁人无证书签名方案

无证书公钥密码系统克服了基于证书公钥密码系统的证书管理问题和基于身份公钥密码系统的密钥托管问题, 并保留了他们所有的优点.为了使公钥能够快速更新, 在2001年, Boneh等引入在基于RSA密码体制中获得公钥快速更新的有效方法, 提出带仲裁人密码学的概念.在 PKC 2004, Sherman等提出了安全仲裁人无证书公钥密码学的正式定义, 并给出了安全仲裁人无证书加密方案的一般构造方法, 构造了一个具体的加密方案, 还给出了相应的安全模型, 但并没有给出签名方案.本文给出了一个新的基于双线性对的带裁人无证书签名方案.     

前向安全门限签名方案

提出了一个新的前向安全门限签名方案,方案采用乘法共享的方法,实现十分简单,使用的密钥长度也很短,在参与成员n=t＋1时,可抵御收买t个成员的窃听敌手．假设因式分解是难解的,证明了方案在随机预言模型中是前向安全的．最后,给出了抵御恶意敌手的方法．     

安全加密的环签名混淆器

构造了一个安全的混淆器来实现对特殊的加密的环签名功能的混淆。这个特殊的加密的环签名功能是由waters的环签名方案和线性加密方案组合实现的。在标准模型下,构造的混淆器满足有关联预言的平均情况虚拟黑盒性质(ACVBP w.r.t.dependent oracles)。有了这个性质,即使敌手在获得混淆后的具有加密的环签名功能程序,环签名依然是匿名的和不可伪造的。     

Boneh-Franklin加密系统的两个扩展方案

基于Boneh-Franklin加密系统,本文给出了两个安全扩展方案,使之能应用于开放式环境中.与原方案相比,其优点:1.没有降低其安全性要求;2.用户的私钥具有保密性;3.用户的ID的数目和密文的长度没有增加.     

标准模型下基于身份代理签名方案的密码学分析

通过对标准模型下基于身份的代理签名方案的安全性分析,指出了该方案主要存在3个不安全因素:不诚实的原始签名人可以伪造任何用户的代理签名;不诚实的代理签名人可以伪造以任何用户为原始签名人的代理签名;外部敌手可以伪造任何原始签名人和代理签名人对任意消息的代理签名.运用密码学分析方法证明了该方案安全性不高,不符合强不可伪造性要求.     

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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