This is follow-up to my previous post, Converting OpenSSH public keys. OpenSSH allows one to use an agent that acts as a proxy to your private key. When using an agent – particularly with agent forwarding enabled – this allows you to authenticate to a remote host without having to (a) repeatedly type in your password or (b) expose an unencrypted private key to remote systems. If one is temtped to use SSH keys as authentication credentials outside of ssh, one would ideally be able to take advantage of the ssh agent for these same reasons.