Characterization of modules of finite projective dimension over complete intersections

Let be a finitely generated module over a local complete intersection of characteristic . The property that has finite projective dimension can be characterized by the vanishing of for some and for some .

     

匿名网络Tor设计原理与实现分析

文章讨论了匿名网络Tor的基本组成、特点、工作原理,并使用python计算机语言实现了一个连接到Tor网络后自行选择退出Tor节点的程序。     

终端匿名器数据过滤模块的分析与实现

在Linux系统下开发了一个基于Tor匿名系统的集成化匿名通信软件--终端匿名器,重点对匿名器的数据过滤模块进行介绍.由于Socks代理具有安全性高、控制灵活等优势,文中选择该技术作为数据过滤模块,实现了Http(S)代理与Socks代理问的相互转化.测试结果表明匿名器实现了用户身份信息的隐藏.     

多样化的可控匿名通信系统

随着网络通信技术的发展,Tor匿名通信系统在得到广泛应用的同时暴露出匿名性较弱等不安全因素,针对上述问题,基于节点的区域管理策略提出一种多样化的可控匿名通信系统(DC-ACS),DC-ACS中多样化匿名链路建立机制根据用户需求选择相应区域的节点完成匿名通信链路的建立,同时基于行为信任的监控机制实现对用户恶意匿名行为的控制,并且保证了发送者和接收者对匿名链路入口节点和出口节点的匿名性。通过与Tor匿名通信系统的比较,DC-ACS在具有匿名性的同时,具有更高的安全性和抗攻击的能力,解决了Tor匿名通信系统所存在的安全隐患。     

基于Tor路由算法改进的安全性提高方法

当今社会,互联网的大规模应用使得匿名通信越来越受到关注。对于目前比较流行的匿名通信网络Tor,文章介绍了其基本原理和构架,分析了存在的匿名漏洞与风险,并针对通信链路建立过程中的弱点提出了改进型的路由算法。最后通过构建小型模拟实验网络,对该算法进行了实验模拟,实验的数据结果有效地验证了理论分析。该改进路由算法对Tor网络及其他匿名网络的改进与发展具有现实意义。     

On modules of finite projective dimension over complete intersections

Recently Avramov and Miller proved that over a local complete intersection ring in characteristic 0$">, a finitely generated module has finite projective dimension if for some 0$"> and for some 0$">, Tor}^{R}_{i}(M,f^{n}_{R})=0-f^{n}$"> being the frobenius map repeated times. They used the notion of ``complexity' and several related theorems. Here we offer a very simple proof of the above theorem without using ``complexity' at all.

     

A Traffic Splitting Algorithm for Load Balancing in Tor

As the most popular anonymous communication system, Tor provides anonymous protection for users by sending their messages through a series of relays. Due to the use of the bandwidth-weighted path selection algorithm, many more users choose routers with high bandwidth as relays. This will cause the utilization of high bandwidth routers to be much higher than that of low bandwidth routers, which will bring congestion risk. The Quality of Service (QoS) is difficult to guarantee for users who need delay-sensitive services such as web browsing and instant messaging. To reduce the average load of routers and improve the network throughput, we propose a circuit construction method with multiple parallel middle relays and conduct a dynamic load allocation method. The experiment demonstrates that our proposed method can provide better load balancing. Compared with other multipath anonymous communication networks, our proposed method can provide better anonymity.     

Tor匿名通信网络节点家族的测量与分析

重点关注Tor匿名通信系统的家族(family)设计,从连续两年的Tor网络真实数据中提取了数千个Tor节点家族,揭示了Tor节点家族的规模、带宽、地理分布等规律,同时也研究了超级家族背后的运营者身份。基于测量结果的分析验证了Tor的家族设计在保障其匿名性方面所发挥的不可替代的重要作用。相应的安全性分析说明了恶意Tor节点家族对Tor网络可用性带来的挑战,也揭露了Tor网络中隐藏家族现象的普遍性及其对Tor网络匿名性所造成的威胁。     

The General Structure of Inverse Polynomial Modules

In this paper we compute injective, projective and flat dimensions of inverse polynomial modules as -modules. We also generalize Hom and Ext functors of inverse polynomial modules to any submonoid but we show Tor functor of inverse polynomial modules can be generalized only for a symmetric submonoid.