计算机系统及通信线路的脆弱性致使网络的安全难以保证。数据及系统的安全性、保密性、完整性等受到严重的威胁。所以网上信息的安全和保密是一个至关重要的问题。网络安全问题日益引起社会的重视和关注。因此,网络的安全措施应是能全方位地针对各种不同的威胁和脆弱性,以保证网络系统的安全正常运行。 The fragility of computer systems and communication lines makes it difficult to guarantee the security of the network. Data and system security, confidentiality, integrity and other serious threats. Therefore, the security and confidentiality of online information is a crucial issue. The issue of cybersecurity has drawn increasing attention and concern from the community. Therefore, the network security measures should be able to comprehensively address a variety of different threats and vulnerabilities in order to ensure the safe operation of the network system.