用椭圆曲线加密密钥的三维CA流加密算法初探

在对现有加密法进行研究的基础上,提出了一种新的三维CA随机位流的产生方法,并用椭圆曲线加密算法对其密钥进行二级加密,形成新的加密算法——用椭圆曲线加密密钥的三维CA流加密算法(ECT-CA),该算法具有较大密钥空间和较好安全性,为非对称密钥算法.     

基于AES算法和改进ECC算法的混合加密方案

高级加密标准(AES)和椭圆曲线密码算法(ECC)是对称加密技术和非对称加密技术中的重要算法.首先对AES算法和ECC算法进行了讨论,在对影响ECC算法效率的因素模逆操作进行了改进,提出基于AES算法和改进ECC算法的混合加密方案.该方案具有运算速度快,安全性能高的优点,具有很好的实用性.     

基于DES和RSA的混合加密机制

密码是一种可以防止信息泄漏的技术.就体制而言，一般分为两类：对称密码体制和非对称密码体制.对称密码体制这类算法用同一把钥匙进行加密解密，适合对大批量数据的加密.常见的算法有DES、IDES、FEAL等.非对称密码算法是发信人和接信人之间需要进行密钥交换，目前常用的公钥密码系统基于由RSA Data Security获得专利的算法.非对称密码体制使用公钥（Public key）和私钥（private key）进行认证，签名，加密等，公钥和私钥是同时生成的，成为一对钥.用你的公钥加密的数据只有用你的私钥才能解密。     

椭圆曲线密码体制在无线网络环境中的应用

椭圆曲线密码体制是一种高比特强度的公钥密码体制，它具有对时间和空间资源要求不高的优点，适合将该算法应用于无线网络环境中，讨论了应用椭圆曲线密码体制实现数据加密、解密、数字签名的过程。     

基于Arnold cat映射与ECC的图像加密方法

提出了一种基于Arnold cat映射以及椭圆曲线密码体制的图像加密算法.首先对图像用Arnold cat变换进行置乱,用Logistic混沌系统产生的整数序列替换Arnold cat变换的参数空间,从而抵制图像置乱部分的周期迭代攻击.再对图像像素依次用椭圆曲线加密体制进行加密,将置乱图像划分为大小相同的图像块,为每一图像块分配相同的密钥,在保证了安全性能的同时也大大提高了算法效率.理论分析和实验结果表明,该算法安全性能高,加密效果理想,是一种可靠的加密方法.     

基于椭圆曲线算法的数字签名技术研究

椭圆曲线密码体制是一种高安全性、高效率的公钥密码体制,它已逐渐取代RSA加密算法,成为下一代公钥加密的标准。本文介绍了基于椭圆曲线算法的数字签名技术的基本原理及其安全性,展望了公钥密码体制未来的发展方向。     

基于Logistic映射的分组密码算法研究及其应用

针对传统分组加密算法仅仅依赖于算法设计 ,初始密钥始终不变的不足 ,提出利用Logistic映射改进分组密码算法的思想 .实现了基于混沌序列的DES算法 ,先用Logistic映射定时迭代产生的伪随机序列 ,然后经过变换后作为DES算法的密钥 ,使其分组加密算法得密钥也处于不断的变化之中 ,从而提高加密强度 .并给出了改进算法加密图像数据的应用实例 ,分析比较了改进后的算法和传统分组密码算法在安全性和抗破译性方面的性能 .     

椭圆曲线公钥密码加密方法的C语言实现

随着计算机网络与通信技术的迅速发展,信息安全问题日益突出。解决此问题的一种有效方法是数据加密与解密技术。本文从实现的角度,对椭圆曲线公钥密码加密方法进行了研究。论述了椭圆曲线运算的数学背景,以及椭圆曲线加密算法的原理,我的主要工作是用C语言编程实现了该方法。     

基于签名加密算法的手机支付系统的研究与实现

通过分析椭网曲线密码体制和对称加密体制,提出了一种新的签名加密算法,它集密钥交换、数字签名和数据加密解密功能于一体.针对手机自身的特点,设计了一种基于该算法的手机支付系统,并进行了安全性和有效性分析.     

基于Logistic映射的分组密码算法研究及其应用

针对传统分组加密算法仅仅依赖于算法设计，初始密钥始终不变的不足，提出利用Logistic映射改进分组密码算法的思想．实现了基于混沌序列的DES算法，先用Logistic映射定时迭代产生的伪随机序列，然后经过变换后作为DES算法的密钥，使其分组加密算法得密钥也处于不断的变化之中，从而提高加密强度．并给出了改进算法加密图像数据的应用实例，分析比较了改进后的算法和传统分组密码算法在安全性和抗破译性方面的性能．     

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.     

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.     

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。     

A computer generator for randomly layered structures

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

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.     

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.     

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。     

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

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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     

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