SSH also supports public key authentication, in addition to traditional passwords, which is more secure. While the encryption that SSH employs using protocol 2 is strong, the greatest encryption in the world won't save you if your password is leaked or brute-forced. This is especially catastrophic on a mission-critical server.

Utilizing public key authentication allows you to connect to a host using a private and public key relationship, instead of using a password. By default, SSH will allow a user to log in via either the username/password combination or a username / key pair combination. The first method is only as secure as the password. By utilizing public key authentication, you can bypass the need for a password completely, and connect to a server without being prompted. But if a server still accepts your password as a means of authentication, then public key authentication is not at its strongest point.

On the server end of the SSH connection, it is possible...