SSH with the gpg-agent and Yubikey
Store your authentication keys securily on your Yubikey. Use gpg-agent to ssh to your servers.
GPG
Transfer your GPG keys to your security key
Configuring multiple keys
Restore your GPG keys backup
You have lost your GPG keys and you need to restore your backups. I list the ways to do this.
Backup your GPG keys
You GPG keys are precious, this posts shows how you can back them up securely.
Create a GPG key
GnuPG is a complete and free implementation of the OpenPGP standard which lets you send and receive encrypted emails, amongst other things.