ssh is an extremely useful tool to work remotely and securely on *nix systems.
But the usual password protected access strategy is not the safest way to go; anyone can try to guess your password, use a keylogger attack, etc.
One (big) safety step above is the pubkey (identity) authentication. This uses a pair key-passphrase for remote access.
You can make your system way safer with just 3 simple steps.