The PHI (Private Handahake Information) Protocol put forth in this paper is the control proto- col particularly designed for SSL VPN, by whih the safety protection of SSL VPN is strengthened and a more credi- bly transparent safety tunnel is built.

• 本文提出的PHI(Private Handshake Information)协议是专门为SSL VPN设计的控制协议,通过该协议可以增加SSL VPN的安全保护,建立更为可靠的透明安全隧道。