(1. SSH service overview 21.1. Public key encryption system structure 21.2. SSH service introduction 21.3. SSH version 22. SSH service installation 23. SSH service configuration 34. Start and stop SSH service 35. Use of SSH client 45.1. Windows Mode 45.2. Linux Mode 66. Using Public Key Authentication 76.1. Principles of Public Key Authentication 76.2. Enabling Public Key Authentication in Server 76.3. Using Public Key Authentication in PuTTY Program 76.4. Using Public Key Authentication in openssh-clients Program 11)