口令认证方案的安全性改进及其相应的数字签名方案

本文首先利用离散对数和分子因解问题提出了许多口令认证方案。其次建立并分析了三个新型数字签名方案。     

加强广义El Gamal型签名方案的安全性

本文提出了一种称作隐式ＥｌＧａｍａｌ型签名方案的新方案。在这种签名方案中，真实签名被隐蔽起来，签名者仅将隐式签名送签名收方。我们在广义ＥｌＧａｍａｌ型签名方案上构造了许多隐式签名方案。分析表明，隐式ＥｌＧａｍａｌ型签名方案不但较源ＥｌＧａｍａｌ型签名方案更安全，而且可以被用来封闭阈下信道以及同时签发两个不同的消息。     

面向ABR业务的公平排队策略

在基于ＡＴＭ－ＴＣＰ技术实现ＡＢＲ中,一个信元的丢失会导致该信元所属分组破坏,致命该信元所属分组的网络中传输都变得无效,重传机制来确保传输正确性,分组多次重传浪费大量带宽,并进一步加剧网络拥塞状况。ＡＴＭ－ＴＣＰ只保证每个信元对网络访问的公平性,而忽略了ＴＣ究组的公平性。本文提出了一种与分组长度无关的公平排队策略,提出以抛弃信元的代价为权值,来决定要抛弃的信元。它不仅能保证分组的公平性,而且能使网     

Pereormance analysis of slotted ALOHA for land mobile satellite networks

The ALOHA protocol has been proposed for accessing reservation channels in demand-assigned channel access protocols for land mobile satellite communications networks. This paper provides a rigorous performance analysis of both the slotted ALOHA protocol and two-packet replication ALOHA protocol taking into account the effects of the fading multipath communications environment. Throughput, delay and stability of these two protocols are determined using a Gilbert channel error model with memory. Comparison of slotted ALOHA and two-packet replication ALOHA shows that a smaller average delay can be achieved by replication. Moreover average throughput is improved in some cases. However replication reduces stability.     

A distributed media access protocol for packet radio networks and performance analysis. Part 1: Network capacity

A distributed time-slot assignment protocol is developed for a mobile multi-hop broadcast packet radio network, using time division multiple access channel access and virtual circuit switching. The protocol eliminates the single point failure mode of centralized network management and the delays of centralized processing. It is applicable to the user-to-user communications functions of such systems as the U. S. Army's enhanced position location and reporting system (EPLRS). The important functions of the distributed protocol, including time-slot assignment, virtual circuit set-up, and network synthesis, are identified, and implementing algorithms are presented and verified. The performance analysis of the protocol is divided into two parts. In this paper, Part 1 of the performance analysis, the capacity of a network using this protocol is studied and a tool is developed to design the network capacity by trading off among the network area, the transmission range, and the number of packet radio units. Since these results are not in closed form, numerical results provide insight into these parameters. In Part 2 the network set-up time and network data rate are analysed and a hierarchical architecture for the distributed protocol is proposed and analysed.     

蜂房移动通信系统分组预约多址（PRMA）协议的性能

本文首先给出了分组预约多址（ＰＲＭＡ）协议的基本性能，接着给出了ＰＲＭＡ的动态性能和多载波ＰＲＭＡ的性能，最后给出了ＰＲＭＡ的改进方法。     

基于软硬件协同的机群数据通信机制的研究与实现

针对各种机群互连网络中，由于软硬件协议之间缺乏紧密的配合，而导致网络提供给最终用户的通信效率较低这一问题。提出了基于硬件描述符机制的网卡设计方法和软硬件协同的思想，设计相应的机群通信协议。实现了高性能的机群互连网络，有效提高了机群用户的通信效率及机群互连网络的通信性能     

一种新的无散列函数单/多密钥交换协议

文章提出一种新的基于离散对数的单/多密钥交换协议.本协议具有身份认证功能,可以避免DiffieHellman协议中存在的漏洞--中间人攻击,而且它不使用散列函数,即可进行单密钥交换又可进行多密钥交换.与基于离散对数签名方案的变体的那一类密钥交换协议[7,8]相比,本协议具有一定程度的隐私性.     

并行组合扩频通信的数据调制映射法和安全通信协议方式＊

并行组合扩频通信是一种高效率的新型扩频通信方式.本文提出了并行组合扩频通信的数据调制映射法,并以此为基础,给出了一种安全通信协议方式,既可作身份认证又有好的保密能力。     

基于CAN总线的网络监控系统

CAN(Controller Area Network)总线属于现场总线(field Bus)的范畴。介绍一种基于CAN总线的网络监控系统方案。该系统由上位机(PC机)、下位机(单片机F040)组成，采用CAN卡和单片机本身集成的CAN模块作为上、下位机通讯接口。上位机与CAN卡的接口采用VB编写，本文还给出了单片机中CAN模块通信的数据处理方法。