Great SSH Agent for OS X

There is a wonderful SSH key management system for OS X called SSHKeychain. It loads your SSH keys, allowing you to log into an SSH server via public key authentication without needing you to type your password each time (i.e. without sending your password to the remote host, which may have been compromised). It is the OS X equivalent of the PuTTY suite for Windows.

Tip: Get passwordless authentication working before installing SSHKeychain (by creating a private/public key pair using ssh-keygen -t rsa, saving to the default location), then copying the contents of the .pub key file into the ˜/.ssh/authorized_keys file on the host you want to SSH to. Ensure that ssh-agent is running on your local machine. Then try to SSH into the remote host—you should be asked to enter the passphrase for the RSA key you just generated (this is not sent to the remote machine).

Now install SSHKeychain (read the README file, and remember to logout and back in again), and add the private key you just generated to its list of keys. When you next try to SSH into the remote host, SSHKeychain should ask you for the passphrase for the key, which it will then keep in memory for subsequent SSH logins to that remote host (i.e. you only enter the key’s passphrase the first time you SSH into the host per local login session).

Here is a good tutorial on all this.