一、概述 随着计算机网络的飞速发展和普遍应用,网络安全问题已成为政府、企业及广大网络用户最关心的问题之一,如何在发展和推广网络应用的同时进一步提高网络的安全性就成了网络界所必须研究和解决的新课题。 计算机网络安全涉及许多方面,其中包括单机环境中的安全性问题,在此本文不作讨论。网络用户有合法使用一定资源的权利,表现为有权和某些结点建立连接,而非法用户企图建立连接时理所应当地予以拒绝,这就涉及到连接的安全性问题。网络站点之间通过传输媒体(如电话线、电缆、光纤、微波等)交换数据的这种信息传输方式是计算机网络提供的最基本功能。因此,数据传输的准确性、机密数据的保密性也 I. Overview With the rapid development and widespread application of computer networks, network security has become one of the most concerned issues for the government, enterprises and the vast majority of network users. How to further improve network security while developing and promoting network applications is becoming The network must study and solve new issues. Computer network security involves many aspects, including security issues in a stand-alone environment, which are not discussed here. Internet users have the right to use certain resources legally, which means that they have the right to establish connection with some nodes, and illegitimate users should deny them when trying to establish a connection. This involves the security of connection. This kind of information transmission between network sites through the transmission media (such as telephone lines, cables, optical fibers, microwaves, etc.) is the most basic function provided by a computer network. Therefore, the accuracy of data transmission, confidentiality of confidential data also