Public/private key pair
From VPS Wiki
An SSH public/private key pair is a convenient method for establishing SSH connections to multiple servers without having to remember different passwords for each server access.
[edit] Plesk
If you wish to use your personal SSH key pair for login, you need to place it on your server. Use the following commands from the secure shell:
mkdir ~/.ssh/
touch ~/.ssh/authorized_keys2
pico -w ~/.ssh/authorized_keys2
Then copy the entire block of text displayed in the public key field into the file authorized_keys2 and save the file. When you establish an SSH connection to your server the next time, you will be able to log in as root with the password of your personal SSH key pair.
