I have been using a Yubico Yubikey NEO security token to store my GnuPG private keys for about a year now. The Yubikey is a powerful security token and I wanted to make use of it to manage my SSH keys as well. I also recently transitioned to the newer GnuPG ‘Modern’ 2.1.x release and there are significant changes to how you would go about using your GPG keys for SSH. Since I ran into a few issues, and the existing documentation on the web is somewhat lacking, I thought I would write up some notes documenting how I did it, and how I solved at least one issue I was having with the interaction between the the Yubikey and the
gpg-agenton OS X.