[GunniH]

I use the YubiKey for SSH auth on several servers but didn't go the GPG route. I opted for the challenge SSH mode using PAM.

  Using username "gunni".
  Using keyboard-interactive authentication.
  YubiKey for `gunni':
  Using keyboard-interactive authentication.
  Password:
  Last login: Tue Jan  14 14:07:02 2018 from X
  [gunni@box ~]#

Works like a charm but I might look into the PGP variation if one of you can hard sell it to me.