Using SSH public key anthentication makes the SSH login process securer and easier, that you don’t need to remember the password.
First make sure you have the local SSH “private/public keypair” ready. If not, run “ssh-keygen” to create.
Then you just need to run the following command:
# "x.x.x.x" is the target host, "username" is the login account on the host.
# After you input your password and login, it's all set. From now on you
# don't need to input password when running "ssh email@example.com".