SSL协议的概述 TCPP协议栈中的安全 Http FTP SMTP S/MIME PGP SET HttpftPsmTp SSL or tls Kerberos SMTP Http TCP UDP TCP IP/IPSec IP (a)Network Level b)Transport Level (c)Application Level Figure 14.1 Relative Location of Security Facilities in the TCP/lP Protocol Stack2 TCP/IP协议栈中的安全 一、SSL协议的概述