信息安全是自古以来就存在的概念，比如以前为了保证传递书信的保密性，使用腊封或其它方式将书信封装在信封内；还有使用暗号口令确认接受信息的人的身份等等方法。需要注意的是，信息安全技术是跟信息的载体形式和传送媒介密切相关的，信息载体的变化和信息传送媒介的变化必然会导致信息安全技术的变化发展。-Information security is the concept existed since ancient times, such as the previous pass in order to ensure the confidentiality of correspondence, the use of wax to seal letters or otherwise encapsulated in an envelope　also use the password confirmation signal the identity of the person receiving the information, etc. methods. Note that, information security technology is the carrier with the form and send the information closely related to the media, information carriers and information transmission medium changes will inevitably lead to changes in information security technology change and development.