Abstract: The wide use of Internet makes it an urgent problem to solute the network security.At the same time, the technology of Modem develops quickly, but Modem is poor in security.TO solve network security on the base of Modem, this paper brings safe measure into transfer protocols, provides a file transfer protocol--Modem -C, then explains its work procedure with an example.

摘要： 互联网的广泛应用．使得网络安全成为必须解决的迫切问题。同时，Modem技术发展很快，但Modem本身安全功能很弱。针对Modem基础上的网络安全，在通信协议上引入安全措施，提出具有加解密功能的Modem-C文件传输协议，并举例说明协议的工作过程。

关键词: 调制解调器, 文件传输协议, 网络安全

CLC Number: 

• TN915.05