PAM two factors authentication

[André Rodier <andre@rodier.me>]

Hello all,

I can use various second factors authentications on Debian:

- google authenticator
- u2f key
- yubikey

I would like to configure pam sessions to have 1) password 
authentication, and then 2) one of the second factor described above.

How this can be achieved, please ?

Thanks for your answers.

André Rodier.