Keystrokes :.

Well, here’s the story: you can connect via ssh to other hosts without entering your password as long as you can prove that you are authorized to login with that identity. This is achieved by placing a public key on the host you want to connect to, so that when you try to login an authentication handshake is prompted to your machine that is then supposed to own the corresponding private key and thus to be able to complete the handshake.

This is what happend behind, you won’t see anything of this during your ssh login. But in order to make this mechanism work, you have to place that public key on the host you want to connect to. Probably for this purpose you may want to use your public RSA key generated to use ssh, that you can find in ~/.ssh/id_rsa.pub where ‘~’ is your home folder ( please be careful not mismatching this with ~/.ssh/id_rsa that is your private key: instead take care of this file by setting proper permissions and/or encryption because this file represent your identity and if leaked, anyone can access any machine where your public key is placed to consider you an “authorized” user ).

The place where ssh daemon looks for authorized keys when someone try to connect to the system as the given user is, with very small imagination, the ~user/.ssh/authorized_keys file, where ~user is the home of the user you are trying to login as e.g. with ssh user@whaterver-host.com. So basically what you have to do is append your own ~/.ssh/id_rsa.pub to the remote ~user/.ssh/authorized_keys. Here is a command you can use ( you will have to prompt the password two last times ).

ssh user@whaterver-host.com 'if [ ! -d ~/.ssh ];then mkdir ~/.ssh; fi'; 
cat ~/.ssh/id_rsa.pub | \
  ssh user@whaterver-host.com 'cat >> ~/.ssh/authorized_keys'

Now you will be able to login to whaterver-host.com just with ‘ ssh user@whaterver-host.com ‘ without being prompted for any password, even from many machines if you keep your id_rsa pair with you across them.( But remember, keep it safe! )
Cheers!