一种基于混沌系统的密钥生成方法

根据类Hénon混沌系统对初始条件和参数的敏感性以及迭代过程的伪随机性,提出了一种基于类Hénon混沌系统的密钥序列生成算法.该算法将参数和初值带入混沌映射,经过迭代产生任意长度的混沌序列,并将其进行量化,量化后得到的密钥序列具有良好的统计特性.另外,还通过计算机实验,对所生成的混沌序列进行了分析.结果表明,这种算法生成的混沌序列具有随机性好,分布均匀的特点,且有较大的密钥空间,可以有效地保障明文的安全.     

Hénon映射的Hopf分岔分析及PSpice电路模拟

以3阶Hénon映射作为研究对象,应用一类分岔临界准则和投影法分别分析了Hénon映射的Hopf分岔临界值和分岔解的稳定性.并以此数学模型为依据,设计了Hénon电路,基于OrCAD/PSpice建立了相关仿真模块,成功地对Hénon映射的Hopf分岔现象进行了电路模拟.模拟结果表明:该方法可以作为研究非线性动力学现象的一种有效手段,可以有效而直观地对非线性动力学进行研究和分析.     

基于二维混沌系统的Hash函数构造算法

在分析带有正弦因子的类Hénon混沌系统基础上,提出了一种混沌Hash函数的构造算法.该算法在二维Hénon混沌系统中引入正弦因子进行迭代,产生混沌序列,然后通过混沌调制方式将明文信息注入均匀分布的混沌轨迹中,以轨迹的量化结果作为明文的Hash值.这种混沌Hash函数不仅具有不可逆性、很好的单向性,而且Hash结果的每一比特都与明文和初始条件有着敏感而复杂的非线性关系.仿真实验与结果分析表明,该Hash函数满足一定的安全性要求,构造算法简单易于实现.     

基于广义Arnold混沌映射和Hénon混沌映射的小波水印算法

为提高水印信息的隐秘性和抗攻击性,将混沌映射运用于数字水印过程中,提出了一种基于广义Ar- nold混沌映射和Hénon混沌映射的小波水印算法。首先用Arnold混沌映射将二值水印图像置乱,作为第一层加密,再利用Hénon混沌序列对水印图像数据进行置换,作为第二层加密,并将加密后的水印图像嵌入到原始图像的DWT域系数中,得到嵌入了水印的图像。混沌映射的伪随机性和初值敏感性保证了水印信息的安全性。实验结果表明,此方法对噪声、压缩、裁切等操作具有很好的鲁棒性。     

迭代混沌映射的S盒构造方法

置换盒又称为S盒,是分组密码中常采用的重要部件.首先对评价S盒性能的指标进行了分析,以非线性度、完全雪崩准则、输出比特间独立性、差分均匀性和双射作为主要的评价指标.然后利用混沌系统在相空间的高度非线性,提出了一种迭代混沌映射的S盒构造方法.仿真检测表明,利用该算法产生的S盒具有很好的密码学特性,为开发新的分组密码算法和动态S盒加密方法奠定了很好的基础.     

基于环面自同构的混沌公钥密码算法分析

混沌映射因其自身特性已经在私钥密码系统中得到了广泛的应用,但在公钥系统中的研究还很少. 本文介绍了一种基于典型的混沌映射环面自同构的类RSA混沌公钥密码算法, 并对其进行了抗攻击分析,经过分析可以看出该算法在某些抗攻击方面性能要优于传统的RSA算法.     

一种混沌双变换图像加密算法的分析与改进

对一种基于位置和灰度双重变换的混沌图像密码算法进行了密码分析,找出了一种基于选择明文攻击的密码破解方法,进而提出了一种改进的混沌双变换型图像加密算法,并对改进算法进行了安全性分析和仿真实验．理论分析和实验结果表明,改进算法能抵御选择明文攻击,且其多项其它密码学性能也有明显的改善．     

基于动态复合混沌系统的S盒设计

S盒是分组密码中重要的非线性部件之一.基于多混沌系统及复合思想,并引入Arnold映射置乱算法,提出了一种混沌S盒的产生方法.首先,提出了几种混沌方程,并对方程的自相关性和互相关性进行了分析,证明它们具有很好的伪随机性.接着,引入了动态复合混沌系统,形成了一种新的混沌系统.运用线性同余发生器可以延长混沌周期的思想,结合动态复合混沌系统,形成了一种新的伪随机序列的产生方法.将所形成的伪随机序列构造成临时的S盒,再利用Arnold映射将临时S盒置乱形成新的S盒.最后,对所产生的S盒做了严格的性能测试,并将本文S盒特性与前人提出的S盒进行了对比,对比分析显示本文所提出的算法产生的S盒具有良好的密码学性能,在空间网络安全及轻量级密码中具有很好的应用前景.     

迭代混沌映射的S盒构造方法

置换盒又称为S盒,是分组密码中常采用的重要部件。首先对评价S盒性能的指标进行了分析,以非线性度、完全雪崩准则、输出比特间独立性、差分均匀性和双射作为主要的评价指标。然后利用混沌系统在相空间的高度非线性,提出了一种迭代混沌映射的S盒构造方法。仿真检测表明,利用该算法产生的S盒具有很好的密码学特性,为开发新的分组密码算法和动态S盒加密方法奠定了很好的基础。     

基于组合进化算法的混沌系统控制与同步

混沌系统控制与同步可通过优化方法设计控制律引导混沌系统轨道来实现.构造适当的适应度函数,将混沌系统的控制与同步问题转化为一个多维的数值优化问题,然后提出一种新的组合进化算法来求解该优化问题.该算法利用佳点集方法初始化种群个体以保证其均匀分布在搜索空间中.在迭代过程中,组合不同进化算子以产生若干个新的子代个体以保持种群的多样性.以典型的Hénon混沌系统为例进行仿真实验,结果表明了该方法是解决混沌系统控制与同步的一种有效方法.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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     

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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