具有不可链接性的无线通信匿名认证

客户端-服务器认证协议的匿名性指服务器能够认证客户端的真实性,但无法获知客户端的身份。针对认证协议提出了新的安全性需求—不可链接性,该性质是对匿名性的有益补充。对已有文献中的认证协议进行修正,使其在不降低认证效率的前提下满足不可链接性。修正后的方案同时提供身份保护性、不可链接性、双向认证、密钥协商、密钥更新、会话密钥的后向保密性以及客户端的口令修改功能。     

基于移位矩阵优化的LDPC码构造

环的存在对准循环LDPC（Low Density Parity Code）码的译码效率造成很大影响,拥有尽可能好的girth分布的校验矩阵对于码的性能改善有着重要的意义。首先对准循环LDPC码校验矩阵的girth分布进行分析,然后在母矩阵和移位矩阵之间设定一个合理的约束关系,使得构造后的校验矩阵最小环长及平均最小环长追求最大化,最后提出了一种易于实现的具有高girth的QC-LDPC（Quasi cyclic-Low Density Parity Code）码构造方法。仿真结果表明,该方法尽量减少码中的短循环,能构造实用化的好码。     

机密过程模型：一种量化机密泄漏的方法

In this paper, we propose a theoretical-in-formation Confidential Procedure Model (CPM) to quantify confidentiality ( or information leakage ). The advantages of the CPM model include the fol-lowing: 1) confidentiality loss is formalized as a dy-namic procedure, instead of a static function, and described via the “waterfall” diagram; 2) confiden-tiality loss is quantified in a relative manner, i. e., taken as a quantitative metric, the ratio of the condi-tional entropy being reserved after observing the entropy of the original full confidential information; 3) the optimal attacks including exhaustive attacks as well as all possible attacks that have (or have not even) been discovered, are taken into account when defining the novel concept of the confidential de-gree. To elucidate the proposed model, we analyze the information leakage in side-channel attacks and the anonymity of DC-net in a quantitative manner.     

兼顾个别化学习的网络教学模式—也评“高等数学”教学设计

随着计算机网络技术的发展，网络教学在我国各种层次的学校中已蓬勃展开，它为现代教育带来了新观念，新方法和新技术，本结合“高等数学”课件设计，对课件的制作，内容选取，表现方式等方面逐一分析，希望人们能在此基础上对网络教学的内涵有进一步的理解和认识。     

基于广义切比雪夫多项式的身份基加密体制安全性分析

Chebyshev polynomials are used as a reservoir for generating intricate classes of symmetrical and chaotic patterns, and have been used in a vast amount of applications. Using extended Chebyshev polynomial over finite field Zp , Algehawi and Samsudin presented recently an Identity Based Encryption (IBE) scheme. In this paper, we showed their proposal is not as secure as they claimed. More specifically, we presented a concrete attack on the scheme of Algehawi and Samsudin, which indicated the scheme cannot be consolidated as a real alternative of IBE schemes since one can exploit the semi group property (bilinearity) of extended Chebyshev polynomials over Zp to implement the attack without any difficulty.     

基于初等数论的圈长8规则准循环LDPC码

This paper is concerned with (3, n ) and (4, n ) regular quasi-cyclic Low Density Parity Check (LDPC) code constructions from elementary number theory. Given the column weight, we determine the shift values of the circulant permutation matrices via arithmetic analysis. The proposed constructions of quasi-cyclic LDPC codes achieve the following main advantages simultaneously: 1) our methods are constructive in the sense that we avoid any searching process; 2) our methods ensure no four or six cycles in the bipartite graphs corresponding to the LDPC codes; 3) our methods are direct constructions of quasi-cyclic LDPC codes which do not use any other quasi-cyclic LDPC codes of small length like component codes or any other algorithms/cyclic codes like building block; 4)the computations of the parameters involved are based on elementary number theory, thus very simple and fast. Simulation results show that the constructed regular codes of high rates perform almost 1.25 dB above Shannon limit and have no error floor down to the bit-error rate of 10-6 .     

面向灾备的高性能可信存储系统设计

针对当前灾备存储系统数据冗余度高的不足,文中提出了将纠删码技术与P2P技术相结合的可信存储系统架构。并设计了与纠删码技术相匹配的分布式散列表,使得系统更快速有效的定位和获取资源;实现了比传统P2P存储系统更完善的管理机制,克服了其存在废弃数据的缺点,能够彻底的删除废弃文件,有效利用存储资源。文中还提供了有效的数据恢复机制,即使灾难来,临,部分存储服务器损坏,系统也能恢复丢失的数据。     

兼顾个别化学习的网络教学模式——也评“高等数学”教学设计

随着计算机网络技术的发展 ,网络教学在我国各种层次的学校中已蓬勃展开 .它为现代教育带来了新观念、新方法和新技术 .本文结合“高等数学”课件设计 ,对课件的制作、内容选取、表现方式等方面逐一分析 ,希望人们能在此基础上对网络教学的内涵有进一步的理解和认识 .     

基于Hadoop的高效分布式取证:原理与方法

随着信息技术的发展以及各种智能设备的普及,设备的平台多样化使得现有电子数据勘查取证分析装备已不能满足网络和存储技术所需要的高速数据镜像存储和海量数据相关性分析等要求,并表现出操作复杂、效率低等缺陷。设计并实现了一种高效的基于Hadoop的分布式取证系统,它能够支持多介质并行取证的工作场景,并通过调度控制服务将不同的证据介质中的数据存储到不同的分布式数据存储服务器上,每个取证任务运行时都可以独占一个取证介质,从而实现多介质的并行取证分析。实验数据显示,搜索一个2~4 GB的文本数据的响应时间可以达到仅0.1 s。