Currently, when I ssh into my linode box, I just type "ssh <my ip>" and then type in my regular linux account password. I have another account (not linode, somewhere else), however, that doesn't let me do this. Instead I had to create a public/private key pair, give the public one to the remote machine and keep the private one on my home machine. And then, when I log in to their machine, I don't use my password, but rather a passphrase I created with those keys.

What are the security trade-offs of these approaches? As I understand it, when I type "ssh <my ip>", without the key pair setup, ssh, on-the-fly, does a public key followed by symmetric key transaction.

Thanks for any help.