identity.pub is the public keyfile for SSH version 1. It is more perforated than an average honeycomb. I would suggest disabling it on the server side ( /etc/ssh/sshd_config ) for starters.
Now, we're left with ssh version 2. You can either generate RSA keys (~/.ssh/id_rsa and ~/.ssh/id_rsa.pub ) or DSA keys( in similarly named files ). Use ssh-keygen -trsa ( or -tdsa ) respectively on the ssh client side.
append your public key files to ~/.ssh/authorized_keys on the SERVER side. You should be good to go.