Some remarks on the TKIP key mixing function of IEEE 802.11i

Temporal key integrity protocol (TKIP) is a sub-protocol of IEEE 802.11i. TKIP remedies some security flaws in wired equivalent privacy (WEP) protocol. TKIP adds four new algorithms to WEP: a message integrity code (MIC) called Michael, an initialization vector (IV) sequencing discipline, a key mixing function and a re-keying mechanism. The key mixing function, also called temporal key hash, de-correlates the IVs from weak keys. Some cryptographic properties of the substitution box (S-box) used in the key mixing function are investigated in this paper, such as regularity, avalanche effect, differ uniform and linear structure. Moen et al pointed out that there existed a temporal key recovery attack in TKIP key mixing function. In this paper a method is proposed to defend against the attack, and the resulting effect on performance is discussed.     

Filling the gap between voters and cryptography in e-voting

Cryptography is an important tool in the design and implementation of e-voting schemes since it can provide verifiability, which is not provided in the traditional voting. But in the real life, most voters can neither understand the profound theory of cryptography nor perform the complicated cryptographic computation. An e-voting system is presented in this paper to leverage the use of cryptography. It combines the advantages of voting scheme of Moran-Naor and voting scheme based on homomorphic encryption. It makes use of the cryptographic technique, but it hides the details of cryptographic computation from voters. Compared with voting scheme of Moran-Naor, the new system has three advantages: the ballots can be recovered when the voting machine breaks down, the costly cut-and-choose zero-knowledge proofs for shuffling votes made by the voting machine are avoided and the partial tally result in each voting machine can be kept secret. Foundation item: the National Natural Science Foundation of China (No. 60673076) and the National High Technology Research and Development Program (863) of China (No. 2008AA01Z403)     

预防公交车自燃的措施

预防公交车自燃的关键是把握着自燃的原因机理,提前做好预防措施。1.公交车自燃原因(1)车辆漏油。车辆漏油可以说是引发汽车自燃的重要原因之一,一旦漏油(特别是燃油泄露),混合气达到一定的浓度,加之有明火出现,自燃事故就难以避免。     

强风中高速列车空气动力学性能

基于三雏定常不可压缩Navier-Stokes方程、k-ε两方程湍流模型,采用有限体积法对速度为200 km·h-1的CRH-2动车组在强风环境下运行的空气动力学行为进行了数值模拟,分析了偏航角对列车整车及其各部分的流场结构和气动力的影响,研究了气动力的组成.研究发现:列车的流场结构非常复杂,侧风情况下列车的背风面区域和尾部区域都会产生漩涡,漩涡的产生与从列车表面的脱离的位置随偏航角的变化而变化;整车、头车、中间车和尾车的气动力大小以及组成均不相同;压力场与侧力、升力沿列车纵向的变化情况基本相同,且都比较复杂.分析结果表明:压力主要对侧力和升力影响较大,由于采用了流线型设计,阻力主要来自空气的粘性力,即摩擦力;侧风情况下头车的侧力和倾覆力矩要明显大于其他部分,此时头车的安全性降低.     

基于GIS公交查询系统的设计与实现

本文充分考虑了乘客出行心理后,设计了以换乘次数最少和出行耗时最少作为约束目标的公交出行最优路径算法。利用动态分段技术建立了公交信息数据库,采用Visualc#．NET＋MapX5．0集成开发的方式开发了公交信息查询系统,实现了输入查询或直接对地图操作来获得出行最优路线和换乘方案。系统以济南市公交网络为基础进行了测试,测试结果良好,为居民的出行提供了一个方便、快捷的公交路线查询平台。     

人民路越江隧道工程浦东风塔基坑对黄浦江防汛墙的影响分析

人民路越江隧道工程浦东风塔基坑距离黄浦江防汛墙近,挖深大,基坑工程必然影响到黄浦江防汛墙的安全。该文采用有限元分析软件,分析论证了浦东风塔基坑施工对黄浦江防汛墙安全的影响。     

浅谈城市沥青道路路面维修的施工体会

城市道路路段软土路基较多,经过多年的运营沉降,部分路段出现病害。该文对路面出现的龟裂、坑洞、唧泥、车辙、开裂等病害进行了分析,并提出处理办法,同时提出了病害处治后沥青混凝土路面的加铺方案。     

大体积混凝土承台施工过程中的温控措施

该文指出大体积混凝土温度控制是施工中的一个难点,通水冷却是大体积混凝土的重要温控措施之一。     

成都市中心城污水处理厂规划布局调整研究

随着成都市城市化进程的快速发展,水污染问题日趋严重,建设污水处理厂,解决水污染问题已迫在眉睫。该文首先论述了成都原污水处理厂规划布局相对集中,污水收集、处理设施的建设难度都较大的向题。对比,又论述了:为进一步落实"污水处理集中与分散相结合"的环保政策,加快中心城污水设施建设步伐,改善水环境污染状况,对污水处理厂规划布局进行深入分析研究,并进行适当的调整,为下一步建设实施提供有益的帮助和参考。     

WindowsNT环境下网卡冗余热备的研究与设计

在网卡冗余方面提出一种新方案,即：结合Windows NT操作系统的网络组件,使用NDIS函数库创建中间层驱动程序实现双网卡冗余热备．文中对实现技术给出了较为详细的描述,测试结果表明完全适合高实时性的要求．