The smartcard needs to support openpgp smart cards. You then create an RSA gpg key with three subkeys - signing, encryption, and authentication. You'll have to enable the advanced key-creation mode for the last one. That authentication subkey then becomes your ssh key.

There are plenty of tutorials online, but none are particularly good. I've been meaning to regenerate my keys, so maybe I'll take notes and try to write up a good one.

Here are a few links:

http://wiki.debian.org/Smartcards/OpenPGP http://www.gnupg.org/howtos/card-howto/en/smartcard-howto.ht... https://www.crypto-stick.com/

The last one is interesting - it's a smart card reader and integrated smart card built into a usb stick.