网络系统所面临的安全风险和潜在的安全威胁是与网络应用模式密切相关的。对于不同网络应用环境所面临的安全风险,应当采取适当的安全措施来增强网络系统的安全性。目前,人们提出了各种网络信息安全技术,根据应用模式和技术方法,这些网络信息安全技术大致上可以分成信息交换安 The security risks and potential security threats that the network system faces are closely related to the network application mode. For the security risks faced by different network application environments, appropriate security measures should be taken to enhance the security of the network system. At present, people put forward various kinds of network information security technologies. According to the application modes and technical methods, these network information security technologies can roughly be divided into information exchange security