QR code login through GDM?

[Alan Cox]

> Right now I'm designing an ID card for ambassadors (but hopefully not
> only for them), what we could use not just for nameplate. I really
> would like to have to add somekind of open authentication possibility
> with the ID card - and use it up as extra info if I would like to
> provide my personal business ecard to the user phone. But however, if
> that's possible - not only with that feature. I thought that QR code
> can be used for identification, but yeah, high risk with precious data
> content.
> If anybody has a good idea to this card - don't hesitate to share it.

Sounds like what you actually want is a smartcard and reader, although
you can certainly use QR code for non-secret data (eg username) and PAM
will happily do that too