Generación de claves

boo:~$ test -d $HOME/sshids || mkdir $HOME/sshids
boo:~$ ssh-keygen -t rsa -f $HOME/sshids/idrsa-1

Instalación en un servidor

boo:~$ scp $HOME/sshids/idrsa-1.pub user@server:

boo:~$ scp $HOME/sshids/idrsa-1.pub user@server:
user@server's password:
******
id_rsa-1.pub 100% |*****************************| 217 00:00
user@server:~$ test -d $HOME/.ssh || mkdir $HOME/.ssh
user@server:~$ cat $HOME/idrsa-1.pub >> $HOME/.ssh/authorized_keys
user@server:~$ rm $HOME/idrsa-1.pub

Cambiando permisos de keys

user@server:~$ chmod 0700 $HOME/.ssh/
user@server:~$ chmod 0600 $HOME/.ssh/authorized_keys
user@server:~$ exit

Probando conexion

boo:~$ ssh user@server -i $HOME/sshids/idrsa-1
user@server:~$ hostname
server
user@server:~$ exit