近年来,计算机网络技术不断发展,网络应用逐渐普及。网络已成为一个无处不在、无所不用的工具。越来越多的计算机用户足不出户则可访问到全球网络系统丰富的信息资源,经济、文化、军事和社会活动也强烈依赖于网络,一个网络化的社会已呈现在我们面前。然而,随着网络应用的不断增多,网络安全问题也越来越突出,由于计算机网络联接形式的多样性、终端分布的不均匀性、网络的开放性和网络资源的共享性等因素,致使计算机网络容易遭受病毒、黑客、 In recent years, the continuous development of computer network technology, network applications are gradually popular. The web has become a ubiquitous, omnipresent tool. More and more computer users can access the abundant information resources of the global network system without leaving home, and the economic, cultural, military and social activities are also strongly dependent on the network. A networked society has been presented to us. However, with the continuous increase of network applications, the problem of network security is also becoming more and more prominent. Due to the diversity of forms of computer network connections, the uneven distribution of terminals, the openness of the network and the sharing of network resources, the computer Network vulnerable to viruses, hackers,