摘要： VPN是在开放的互联网上实现安全通信的基础，该文对VPN的相关的密码技术和安全协议等进行了讨论。

关键词: VPN, 密码学, IPSec, SSL, PKI

Abstract: VPN(vrtual private networks) is the base of secure communication in the open Internet. In this article some key techniques in VPN such as the cryptography and security protocols are discussed.

中图分类号: 

• TP393.03